APPENDIX A

                AGREEMENT AND PLAN OF REORGANIZATION AND MERGER


                
 
         On August 22, 1996,  Castelle  ("Castelle"),  Ibex  Technologies,  Inc.
("Ibex") and certain  shareholders  of Ibex  executed an  Agreement  and Plan of
Merger,  dated as of August 22, 1996, pursuant to which Ibex will be merged with
and into  Castelle  (the  "Acquisition").  Upon the  Acquisition,  approximately
790,000  shares  of  Castelle   Common  Stock  will  be  issued  to  the  former
shareholders  of Ibex and  approximately  60,000 shares of Castelle Common Stock
will be reserved  for  issuance  upon the  exercise of Ibex  options  assumed by
Castelle.  The  transaction  is intended to be tax-free under Section 368 of the
Internal  Revenue  Code  of  1986,  as  amended,  and to be  accounted  for as a
pooling-of-interests.  The  transaction  remains  subject to  Castelle  and Ibex
shareholder approval and other closing conditions.

Item 7. Financial Statements, Pro Forma Financial Information and Exhibits.

     (c) The following  exhibits are furnished in accordance with the provisions
of Item 601 of Regulation S-K:

     Exhibit Number        Exhibit

        2.1                Agreement  and Plan of  Merger,  dated as of  August
                           22,  1996,  among Castelle,  Ibex  Technologies, Inc.
                           and Certain  Shareholders  of Ibex Technologies, Inc.

        20.1               Press Release issued August 23, 1996


                                       2







                                    SIGNATURE

        Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned, thereunto duly authorized.


                                    CASTELLE



Dated:  August 30, 1996                       By: /s/ Randall I. Bambrough
                                                  ------------------------
                                                  Randall I. Bambrough
                                                  Vice President of Finance
                                                  and Chief Financial Officer


                                       3




                                INDEX TO EXHIBITS



                                                               Page number in
                                                               sequentially
Exhibit No.    Description                                     numbered version

  2.1          Agreement  and  Plan  of  Reorganization                5
               dated as of August 22, 1996 among Castelle,
               Ibex Technologies, Inc. and Certain
               Shareholders of Ibex Technologies, Inc.
               (incorporated herein by reference to Exhibit
               2.01 to the Registrant's Registration 
               Statement on Form S-4, File No. 33-85840).

  20.1         Press Release dated August 23, 1996                    139

                                       4
                                     

                      AGREEMENT AND PLAN OF REORGANIZATION


                                     among:


                                    CASTELLE,
                            a California corporation;


                            IBEX TECHNOLOGIES, INC.,
                            a California corporation;


                                       and


                 CERTAIN SHAREHOLDERS OF IBEX TECHNOLOGIES, INC.





                           ---------------------------

                           Dated as of August 22, 1996
                           ---------------------------





                                       5





                                                                                                    

                                TABLE OF CONTENTS
                                   
                                                                                                                


 
                                                                                              

                                                                                                            
SECTION 1.        DESCRIPTION OF TRANSACTION.................................................................... 11
         1.1      Merger of Ibex into Castelle.................................................................. 11
         1.2      Effect of the Merger.......................................................................... 12
         1.3      Closing; Effective Time....................................................................... 12
         1.4      Articles of Incorporation and Bylaws; Directors and Officers.................................. 12
         1.5      Conversion of Shares.......................................................................... 12
         1.6      Employee Stock Options........................................................................ 13
         1.7      Closing of Ibex's Transfer Books.............................................................. 14
         1.8      Exchange of Certificates...................................................................... 14
         1.9      Dissenting Shares............................................................................. 15
         1.10     Tax Consequences.............................................................................. 16
         1.11     Accounting Treatment.......................................................................... 16
         1.12     Further Action................................................................................ 16

SECTION 2.        REPRESENTATIONS AND WARRANTIES OF IBEX AND THE DESIGNATED SHAREHOLDERS........................ 16
         2.1      Due Organization; No Subsidiaries; Etc........................................................ 16
         2.2      Articles of Incorporation and Bylaws; Records................................................. 17
         2.3      Capitalization, Etc........................................................................... 17
         2.4      Financial Statements.......................................................................... 18
         2.5      Absence of Changes............................................................................ 19
         2.6      Title to Assets............................................................................... 20
         2.7      Bank Accounts; Receivables.................................................................... 21
         2.8      Equipment; Leasehold.......................................................................... 21
         2.9      Proprietary Assets............................................................................ 21
         2.10     Contracts..................................................................................... 23
         2.11     Liabilities................................................................................... 25
         2.12     Compliance with Legal Requirements............................................................ 26
         2.13     Governmental Authorizations................................................................... 26
         2.14     Tax Matters................................................................................... 26
         2.15     Employee and Labor Matters; Benefit Plans..................................................... 27
         2.16     Environmental Matters......................................................................... 30
         2.17     Insurance..................................................................................... 30
         2.18     Related Party Transactions.................................................................... 31
         2.19     Legal Proceedings; Orders..................................................................... 31
         2.20     Authority; Binding Nature of Agreement........................................................ 32
         2.21     Non-Contravention; Consents................................................................... 32
         2.22     Full Disclosure............................................................................... 33

SECTION 3.        REPRESENTATIONS AND WARRANTIES OF CASTELLE.................................................... 33
         3.1      Due Organization; No Subsidiaries; Etc........................................................ 34

                                       6






                                TABLE OF CONTENTS
                                  (continued)

                                                                                                           
         3.2      SEC Filings; Financial Statements............................................................. 34
         3.3      Capitalization, Etc........................................................................... 35
         3.4      Authority; Binding Nature of Agreement........................................................ 36
         3.5      Absence of Changes............................................................................ 36
         3.6      Title to Assets............................................................................... 38
         3.7      Proprietary Assets............................................................................ 38
         3.8      Liabilities................................................................................... 39
         3.9      Compliance with Legal Requirements............................................................ 39
         3.10     Governmental Authorizations................................................................... 40
         3.11     Tax Matters................................................................................... 40
         3.12     Employee and Labor Matters; Benefit Plans..................................................... 41
         3.13     Environmental Matters......................................................................... 41
         3.14     Legal Proceedings; Orders..................................................................... 41
         3.15     Non-Contravention; Consents................................................................... 42
         3.16     Full Disclosure............................................................................... 43
         3.17     Valid Issuance................................................................................ 43

SECTION 4.        CERTAIN COVENANTS OF IBEX AND THE DESIGNATED SHAREHOLDERS..................................... 44
         4.1      Access and Investigation...................................................................... 44
         4.2      Operation of Ibex's Business.................................................................. 44
         4.3      Notification; Updates to Disclosure Schedule.................................................. 46

SECTION 5.        ADDITIONAL COVENANTS OF THE PARTIES........................................................... 47
         5.1      Filings and Consents.......................................................................... 47
         5.2      California Permit; Fairness Hearing........................................................... 47
         5.3      Ibex Shareholders' Meeting.................................................................... 47
         5.4      Public Announcements.......................................................................... 47
         5.5      Pooling of Interests.......................................................................... 48
         5.6      Affiliate Agreements.......................................................................... 48
         5.7      Best Efforts.................................................................................. 48
         5.8      Tax Matters................................................................................... 48
         5.9      Employment and Noncompetition Agreements...................................................... 48
         5.10     FIRPTA Matters................................................................................ 48

SECTION 6.        CONDITIONS PRECEDENT TO OBLIGATIONS OF CASTELLE............................................... 49
         6.1      Satisfactory Completion of Pre-Acquisition Review............................................. 49
         6.2      Accuracy of Representations................................................................... 50
         6.3      Performance of Covenants...................................................................... 50
         6.4      Shareholder Approval.......................................................................... 50


                                       7




                               TABLE OF CONTENTS
                                  (continued)


                                                                                                           
         6.5      Consents...................................................................................... 50
         6.6      Agreements and Documents...................................................................... 50
         6.7      FIRPTA Compliance............................................................................. 51
         6.8      Securities Compliance......................................................................... 51
         6.9      No Restraints................................................................................. 52
         6.10     Comfort Letter................................................................................ 52
         6.11     No Legal Proceedings.......................................................................... 52
         6.12     Amendment of Fourth Amended and Restated Registration......................................... 52


SECTION 7.        CONDITIONS PRECEDENT TO OBLIGATIONS OF IBEX................................................... 52
         7.1      Accuracy of Representations................................................................... 52
         7.2      Performance of Covenants...................................................................... 53
         7.3      Documents..................................................................................... 53
         7.4      Shareholder Approval.......................................................................... 53
         7.5      No Restraints................................................................................. 53
         7.6      Consents...................................................................................... 53
         7.7      Securities Compliance......................................................................... 53
         7.8      No Legal Proceedings.......................................................................... 54

SECTION 8.        TERMINATION................................................................................... 54
         8.1      Termination Events............................................................................ 54
         8.2      Termination Procedures........................................................................ 55
         8.3      Effect of Termination......................................................................... 55

SECTION 9.        INDEMNIFICATION, ETC.......................................................................... 55
         9.1      Survival of Representations, Etc.............................................................. 55
         9.2      Indemnification by Designated Shareholders.................................................... 56
         9.3      Threshold; Ceiling............................................................................ 56
         9.4      Escrow Fund................................................................................... 56
         9.5      No Contribution............................................................................... 57
         9.6      Interest...................................................................................... 57
         9.7      Defense of Third Party Claims................................................................. 57
         9.8      Exercise of Remedies by Indemnitees Other Than Castelle....................................... 58
         9.9      Claims Against Consideration.................................................................. 58
         9.10     Objections to Claims.......................................................................... 58
         9.11     Resolution of Conflicts; Arbitration.......................................................... 58

SECTION 10.       MISCELLANEOUS PROVISIONS...................................................................... 61

                                       8






                               TABLE OF CONTENTS
                                  (continued)

                                                                                                           
         10.1     Designated Shareholders' Agent................................................................ 61
         10.2     Further Assurances............................................................................ 62
         10.3     Fees and Expenses............................................................................. 62
         10.4     Attorneys' Fees............................................................................... 62
         10.5     Notices....................................................................................... 62
         10.6     Confidentiality............................................................................... 64
         10.7     Time of the Essence........................................................................... 64
         10.8     Headings...................................................................................... 64
         10.9     Counterparts.................................................................................. 64
         10.10    Governing Law................................................................................. 64
         10.11    Successors and Assigns........................................................................ 64
         10.12    Remedies Cumulative; Specific Performance..................................................... 64
         10.13    Waiver........................................................................................ 65
         10.14    Amendments.................................................................................... 65
         10.15    Severability.................................................................................. 65
         10.16    Parties in Interest............................................................................65
         10.17    Entire Agreement.............................................................................. 65
         10.18    Construction.................................................................................. 65

                                       9








 
                           
                                    EXHIBITS

Exhibit A-1  -  Designated Shareholders

Exhibit A-2  -  Signing Shareholders

Exhibit B    -  Certain Definitions

Exhibit C-1  -  Form of Affiliate Agreement

Exhibit C-2  -  Persons to Execute Affiliate Agreements

Exhibit D    -  Forms of Tax Representation Letters

Exhibit E    -  Form of Continuity of Interest Certificate

Exhibit F    -  Persons to Sign Employment and Noncompetition Agreements

Exhibit G    -  Forms of Employment Agreements

Exhibit H    -  Forms of Noncompetition Agreements

Exhibit I    -  Form of Legal Opinion of Graham & James LLP

Exhibit J    -  Form of Legal Opinion of Cooley Godward Castro Huddleson & Tatum

Exhibit K    -  Not Used

Exhibit L    -  Escrow Agreement

Exhibit M    -  Form of Irrevocable Proxy

                                       10
                                     






  
                              
                                  AGREEMENT AND
                             PLAN OF REORGANIZATION


        THIS  AGREEMENT  AND PLAN OF  REORGANIZATION  ("Agreement")  is made and
entered  into as of August  22,  1996,  by and  among:  CASTELLE,  a  California
corporation ("Castelle"); IBEX TECHNOLOGIES, INC., a California corporation (the
"Ibex");  the parties identified on Exhibit A-1 (which are referred to herein as
the  "Designated  Shareholders")  and the  parties  identified  on  Exhibit  A-2
(collectively,  the  parties  identified  on Exhibit  A-1 and on Exhibit A-2 are
referred to herein as the "Signing  Shareholders").  Certain  other  capitalized
terms used in this Agreement are defined in Exhibit B.


                                    RECITALS

     A.  Castelle  and Ibex  intend to effect a merger of Ibex into  Castelle in
accordance  with this  Agreement  and the  California  General  Corporation  Law
("CGCL") (the "Merger").

     B. It is  intended  that the Merger  qualify  as a tax-free  reorganization
within the meaning of Section  368(a) of the Internal  Revenue Code of 1986,  as
amended (the "Code"). For accounting purposes, it is intended that the Merger be
treated as a "pooling of interests."

     C. This Agreement has been approved by the  respective  boards of directors
of Castelle and Ibex.

     D. The Designated  Shareholders  own a total of 96,000 shares of the Common
Stock  (with no par  value)  of Ibex  ("Ibex  Common  Stock");  and the  Signing
Shareholders  own a total of 96,000  shares of Ibex Common  Stock and a total of
48,035  shares of the Series A  Convertible  Preferred  Stock of Ibex ("Series A
Preferred Stock"),  constituting all of the outstanding preferred stock of Ibex.
Contemporaneously  with the  execution  and  delivery  of this  Agreement,  each
Signing Shareholder is executing and delivering to Castelle a Proxy of even date
herewith.


                                    AGREEMENT

        The parties to this Agreement agree as follows:

SECTION 1. DESCRIPTION OF TRANSACTION

     1.1  Merger  of Ibex into  Castelle.  Upon the  terms  and  subject  to the
conditions  set forth in this  Agreement,  at the Effective  Time (as defined in
Section  1.3),  Ibex shall be merged with and into  Castelle,  and the  separate
existence  of  Ibex  shall  cease.  Castelle  will  continue  as  the  surviving
corporation in the Merger (the "Surviving Corporation").

                                       11


     1.2 Effect of the  Merger.  The Merger  shall have the effects set forth in
this  Agreement  and in the  applicable  provisions  of the  California  General
Corporation Law.

     1.3  Closing;   Effective  Time.  The   consummation  of  the  transactions
contemplated by this Agreement (the  "Closing")  shall take place at the offices
of Cooley Godward Castro  Huddleson & Tatum,  One Maritime Plaza, San Francisco,
California  94111 at 10:00 a.m. on September __, 1996, or at such other time and
date  during the period  from  August 15,  1996  through  December  30,  1996 as
Castelle may  designate  upon not less than five days' prior notice to Ibex (the
"Scheduled  Closing Time").  (The date on which the Closing actually takes place
is referred to in this Agreement as the "Closing Date.")  Contemporaneously with
or as promptly as practicable after the Closing,  a properly executed  agreement
of merger conforming to the requirements of Chapter 11 of the California General
Corporation  Law  shall be filed  with the  Secretary  of State of the  State of
California.  The Merger  shall become  effective  at the time such  agreement of
merger is filed  with and  accepted  by the  Secretary  of State of the State of
California (the "Effective Time").

     1.4 Articles of Incorporation  and Bylaws;  Directors and Officers.  Unless
otherwise determined by Castelle prior to the Effective Time:

     (a) the Articles of  Incorporation  of the Surviving  Corporation  shall be
     those of Castelle;

     (b) the Bylaws of the Surviving Corporation shall be those of Castelle; and

     (c) the  directors and officers of the  Surviving  Corporation  immediately
     after the  Effective  Time shall be those of Castelle  with the addition of
     Ney Grant as President of the Ibex Division of Castelle.

     1.5 Conversion of Shares.

     (a) Subject to Sections 1.8(c) and 1.9, at the Effective Time, by virtue of
     the Merger and without any further action on the part of Castelle,  Ibex or
     any shareholder of Ibex:

          (i) If the closing market price of a share of the common stock (no par
          value per share) of Castelle ("Castelle Common Stock") on the business
          day immediately prior to the Closing (the "Preference Price") is $9.42
          or greater, each share of Ibex Common Stock and each share of Series A
          Preferred Stock  outstanding  immediately  prior to the Effective Time
          shall be  converted  into the right to receive  4.171124044  shares of
          Castelle Common Stock.

          (ii) If the  Preference  Price is less than $9.42,  (i) the  aggregate
          shares of Series A Preferred Stock  outstanding  immediately  prior to
          the  Effective  Time  shall be  converted  into a number  of shares of
          Castelle  Common  Stock  equal to $180,000  divided by the  Preference
          Price  (the  "Preferred  Bonus  Shares"),  and (ii) each share of Ibex
          Common  Stock and each share of Series A Preferred  Stock  outstanding
          immediately  prior to the  Effective  Time shall be  converted  into a
          number of shares of Castelle  Common  Stock equal to (x) 850,000  less

                                       12


          the number of  Preferred  Bonus  Shares  divided by (y) the  aggregate
          number of shares of Ibex  Common  Stock and Series A  Preferred  Stock
          outstanding,  on a  fully  diluted  basis,  immediately  prior  to the
          Effective Time.

     (b) If any shares of Ibex Common Stock outstanding immediately prior to the
     Effective Time are unvested or are subject to a repurchase option,  risk of
     forfeiture  or  other  condition  under  any  applicable  restricted  stock
     purchase  agreement  or other  agreement  with  Ibex,  then the  shares  of
     Castelle  Common  Stock  issued in exchange  for such shares of Ibex Common
     Stock will also be unvested and subject to the same repurchase option, risk
     of forfeiture or other condition,  and the certificates  representing  such
     shares of Castelle Common Stock may accordingly be marked with  appropriate
     legends.

     1.6 Employee Stock Options.  At the Effective  Time, each stock option that
is then  outstanding  under  Ibex's 1992 Stock Option  Plan,  whether  vested or
unvested (a "Ibex Option"),  shall be assumed by Castelle in accordance with the
terms (as in  effect as of the date of this  Agreement)  of  Ibex's  1992  Stock
Option  Plan and the  stock  option  agreement  by which  such  Ibex  Option  is
evidenced.  All rights with respect to Ibex Common Stock under  outstanding Ibex
Options shall thereupon be converted into rights with respect to Castelle Common
Stock.  Accordingly,  from and after the  Effective  Time,  (a) each Ibex Option
assumed by Castelle may be exercised solely for shares of Castelle Common Stock,
(b) the number of shares of Castelle  Common Stock  subject to each such assumed
Ibex  Option  shall be equal to the number of shares of Ibex  Common  Stock that
were  subject  to such  Ibex  Option  immediately  prior to the  Effective  Time
multiplied by the Applicable Fraction (as hereinafter defined),  rounded down to
the nearest whole number of shares of Castelle  Common Stock,  (c) the per share
exercise price for the Castelle Common Stock issuable upon exercise of each such
assumed Ibex Option shall be determined by dividing the exercise price per share
of Ibex Common Stock subject to such Ibex Option, as in effect immediately prior
to the Effective Time, by the Applicable Fraction (as hereinafter defined),  and
rounding the resulting  exercise price up to the nearest whole cent, and (d) all
restrictions  on the exercise of each such assumed Ibex Option shall continue in
full force and effect, and the term, exercisability,  vesting schedule and other
provisions  of such Ibex Option  shall  otherwise  remain  unchanged;  provided,
however, that each such assumed Ibex Option shall, in accordance with its terms,
be subject to further  adjustment  as  appropriate  to reflect any stock  split,
reverse  stock  split,  stock  dividend,   recapitalization   or  other  similar
transaction  effected by Castelle  after the Effective  Time.  Ibex and Castelle
shall take all action that may be necessary (under Ibex's 1992 Stock Option Plan
and otherwise) to effectuate  the provisions of this Section 1.6.  Following the
Closing,  Castelle  will send to each holder of an assumed Ibex Option a written
notice  setting forth (i) the number of shares of Castelle  Common Stock subject
to such assumed Ibex Option,  and (ii) the exercise  price per share of Castelle
Common Stock issuable upon exercise of such assumed Ibex Option. For purposes of
this Section  1.6,  the  "Applicable  Fraction"  shall mean the  exchange  ratio
identified in Section 1.5 which is utilized to convert each share of Ibex Common
Stock outstanding immediately prior to the Merger into Castelle Common Stock.

                                       13


     1.7 Closing of Ibex's Transfer  Books.  At the Effective  Time,  holders of
certificates  representing  shares of Ibex's capital stock that were outstanding
immediately  prior to the  Effective  Time  shall  cease to have any  rights  as
shareholders  of Ibex, and the stock transfer books of Ibex shall be closed with
respect to all shares of such capital stock outstanding immediately prior to the
Effective  Time. No further  transfer of any such shares of Ibex's capital stock
shall be made on such stock transfer  books after the Effective  Time. If, after
the Effective  Time, a valid  certificate  previously  representing  any of such
shares of Ibex's capital stock (a "Ibex Stock  Certificate") is presented to the
Surviving  Corporation,  such Ibex Stock Certificate shall be canceled and shall
be exchanged as provided in Section 1.8.

     1.8 Exchange of  Certificates. 

     (a) At or as soon as practicable  after the Effective  Time,  Castelle will
     send to the holders of Ibex Stock  Certificates (i) a letter of transmittal
     in customary form and containing such provisions as Castelle may reasonably
     specify,  and (ii)  instructions for use in effecting the surrender of Ibex
     Stock  Certificates  in exchange  for  certificates  representing  Castelle
     Common Stock.  Upon  surrender of a Ibex Stock  Certificate to Castelle for
     exchange,  together with a duly  executed  letter of  transmittal  and such
     other  documents as may be reasonably  required by Castelle,  the holder of
     such Ibex Stock  Certificate  shall be  entitled  to  receive  in  exchange
     therefor a certificate  representing the number of whole shares of Castelle
     Common  Stock that such  holder has the right to  receive  pursuant  to the
     provisions  of this Section 1, and Ibex Stock  Certificate  so  surrendered
     shall be canceled.  Until  surrendered as contemplated by this Section 1.8,
     each Ibex Stock Certificate  shall be deemed,  from and after the Effective
     Time,  to  represent  only the  right to  receive  upon  such  surrender  a
     certificate  representing shares of Castelle Common Stock (and cash in lieu
     of any fractional  share of Castelle  Common Stock) as contemplated by this
     Section 1.8. If any Ibex Stock  Certificate shall have been lost, stolen or
     destroyed,  Castelle may, in its discretion and as a condition precedent to
     the issuance of any certificate representing Castelle Common Stock, require
     the owner of such  lost,  stolen or  destroyed  Ibex Stock  Certificate  to
     provide  an  appropriate  affidavit  and to  deliver a bond (in such sum as
     Castelle may reasonably  direct) as indemnity against any claim that may be
     made  against the  Surviving  Corporation  with  respect to such Ibex Stock
     Certificate.

     (b) No  dividends or other  distributions  declared or made with respect to
     Castelle  Common Stock with a record date after the Effective Time shall be
     paid to the holder of any unsurrendered Ibex Stock Certificate with respect
     to the shares of Castelle  Common Stock  represented  thereby,  and no cash
     payment in lieu of any  fractional  share shall be paid to any such holder,
     until such holder surrenders such Ibex Stock Certificate in accordance with
     this  Section 1.8 (at which time such  holder  shall be entitled to receive
     all such dividends and distributions and such cash payment).

     (c) No  fractional  shares  of  Castelle  Common  Stock  shall be issued in
     connection  with the Merger,  and no  certificates  for any such fractional
     shares shall be issued.  In lieu of such fractional  shares,  any holder of
     capital stock of Ibex who would otherwise be entitled to receive a fraction
     of a share of Castelle  Common  Stock  (after  aggregating  all  fractional
     shares of Castelle  Common  Stock  issuable  to such  holder)  shall,  upon

                                       14



     surrender of such holder's Ibex Stock  Certificate(s),  be paid in cash the
     dollar  amount  (rounded  to the nearest  whole  cent),  without  interest,
     determined by multiplying  such fraction by the  Designated  Castelle Stock
     Price.  For purposes of this  paragraph,  the  "Designated  Castelle  Stock
     Price" shall be eight dollars ($8.00) per share of Castelle Common Stock.

     (d) The Surviving Corporation shall be entitled to deduct and withhold from
     any consideration  payable or otherwise deliverable to any holder or former
     holder of capital stock of Ibex pursuant to this  Agreement such amounts as
     the Surviving  Corporation may be required to deduct or withhold  therefrom
     under the Code or under any  provision of state,  local or foreign tax law.
     To the extent such amounts are so deducted or withheld,  such amounts shall
     be treated for all purposes under this Agreement as having been paid to the
     Person to whom such amounts would otherwise have been paid.

     (e) The Surviving  Corporation  shall not be liable to any holder or former
     holder of capital stock of Ibex for any shares of Castelle Common Stock (or
     dividends or distributions with respect thereto),  or for any cash amounts,
     delivered  to any public  official  pursuant  to any  applicable  abandoned
     property, escheat or similar law.

     1.9 Dissenting Shares.

     (a)  Notwithstanding  anything to the contrary contained in this Agreement,
     any shares of capital stock of Ibex that, as of the Effective  Time, are or
     may become "dissenting shares" within the meaning of Section 1300(b) of the
     California  Corporations  Code shall not be converted into or represent the
     right to receive  Castelle  Common Stock in accordance with Section 1.5 (or
     cash in lieu of fractional  shares in accordance with Section 1.8(c)),  and
     the holder or holders of such shares shall be entitled  only to such rights
     as may be granted to such holder or holders in Chapter 13 of the California
     General Corporation Law; provided,  however, that if the status of any such
     shares as "dissenting shares" shall not be perfected, or if any such shares
     shall lose their status as  "dissenting  shares,"  then, as of the later of
     the Effective Time or the time of the failure to perfect such status or the
     loss of such status,  such shares shall automatically be converted into and
     shall  represent  only the  right to  receive  (upon the  surrender  of the
     certificate or certificates representing such shares) Castelle Common Stock
     in accordance  with Section 1.5 (and cash in lieu of  fractional  shares in
     accordance with Section 1.8(c)).

     (b) Ibex  shall  give  Castelle  (i) prompt  notice of any  written  demand
     received by Ibex prior to the  Effective  Time to require  Ibex to purchase
     shares of capital  stock of Ibex  pursuant to Chapter 13 of the  California
     General  Corporation  Law and of any other  demand,  notice  or  instrument
     delivered to Ibex prior to the Effective  Time  pursuant to the  California
     General  Corporation  Law, and (ii) the  opportunity  to participate in all
     negotiations  and  proceedings  with respect to any such demand,  notice or
     instrument.  Ibex shall not make any payment or  settlement  offer prior to
     the Effective  Time with respect to any such demand unless  Castelle  shall
     have consented in writing to such payment or settlement offer.

                                       15




     1.10 Tax  Consequences.  For  federal  income tax  purposes,  the Merger is
intended to constitute a reorganization within the meaning of Section 368 of the
Code.  The parties to this  Agreement  hereby adopt this Agreement as a "plan of
reorganization"  within the meaning of Sections 1.368-2(g) and 1.368-3(a) of the
United States Treasury Regulations.

     1.11 Accounting Treatment.  For accounting purposes, the Merger is intended
to be treated as a "pooling of interests."

     1.12 Further Action.  If, at any time after the Effective Time, any further
action is  determined  by Castelle to be necessary or desirable to carry out the
purposes of this Agreement or to vest the Surviving Corporation with full right,
title and possession of and to all rights and property of Ibex, the officers and
directors of the Surviving Corporation shall be fully authorized (in the name of
Ibex and otherwise) to take such action.

SECTION  2.   REPRESENTATIONS   AND   WARRANTIES  OF  IBEX  AND  THE  DESIGNATED
SHAREHOLDERS

     Ibex and the Designated  Shareholders  severally  represent and warrant, to
and for the benefit of the Indemnitees, as follows:

     2.1 Due Organization; No Subsidiaries; Etc.

     (a) Ibex is a  corporation  duly  organized,  validly  existing and in good
     standing  under the laws of the State of  California  and has all necessary
     power and authority: (i) to conduct its business in the manner in which its
     business is currently  being  conducted;  (ii) to own and use its assets in
     the manner in which its assets are currently  owned and used;  and (iii) to
     perform its obligations under all Ibex Contracts.

     (b) Except as set forth in Part 2.1 of the  Disclosure  Schedule,  Ibex has
     not conducted any business  under or otherwise  used, for any purpose or in
     any  jurisdiction,  any fictitious name,  assumed name, trade name or other
     name, other than the name "Ibex Technologies, Inc."

     (c)  Ibex is not and has not been  required  to be  qualified,  authorized,
     registered  or  licensed to do  business  as a foreign  corporation  in any
     jurisdiction  other than the  jurisdictions  identified  in Part 2.1 of the
     Disclosure  Schedule,   except  where  the  failure  to  be  so  qualified,
     authorized, registered or licensed has not had and will not have a Material
     Adverse Effect on Ibex.  Ibex is in good standing as a foreign  corporation
     in each of the  jurisdictions  identified  in  Part  2.1 of the  Disclosure
     Schedule.

     (d) Part 2.1 of the Disclosure Schedule accurately sets forth (i) the names
     of the members of Ibex's board of directors,  (ii) the names of the members
     of each  committee  of Ibex's board of  directors,  and (iii) the names and
     titles of Ibex's officers.

                                       16



     (e) Ibex does not own any  controlling  interest in any Entity and,  except
     for the equity interests identified in Part 2.1 of the Disclosure Schedule,
     Ibex has  never  owned,  beneficially  or  otherwise,  any  shares or other
     securities  of, or any direct or indirect  equity  interest in, any Entity.
     Ibex has not agreed and is not  obligated to make any future  investment in
     or capital  contribution to any Entity.  Ibex has not guaranteed and is not
     responsible or liable for any obligation of any of the Entities in which it
     owns or has owned any equity interest.

     2.2 Articles of Incorporation  and Bylaws;  Records.  Ibex has delivered to
Castelle  accurate and complete copies of: (1) Ibex's articles of  incorporation
and bylaws, including all amendments thereto; (2) the stock records of Ibex; and
(3) except as set forth in Part 2.2 of the Disclosure Schedule,  the minutes and
other records of the meetings and other proceedings (including any actions taken
by written consent or otherwise  without a meeting) of the shareholders of Ibex,
the board of directors of Ibex and all  committees  of the board of directors of
Ibex.  There  have  been  no  formal  meetings  or  other   proceedings  of  the
shareholders  of Ibex,  the board of directors  of Ibex or any  committee of the
board of directors of Ibex that are not fully reflected in such minutes or other
records.  There has not been any  violation of any of the  provisions  of Ibex's
articles of incorporation  or bylaws,  and Ibex has not taken any action that is
inconsistent  in any  material  respect  with any  resolution  adopted by Ibex's
shareholders,  Ibex's  board of  directors  or any  committee of Ibex's board of
directors.  The books of account, stock records,  minute books and other records
of Ibex are accurate, up-to-date and complete in all material respects, and have
been maintained in accordance with prudent business practices.

     2.3 Capitalization, Etc.

     (a) The  authorized  capital  stock of Ibex  consists  of: (i) ten  million
     (10,000,000)  shares  of Common  Stock  (with no par  value),  of which one
     hundred  forty-one  thousand sixteen  (141,016) shares have been issued and
     are  outstanding  as of the date of this  Agreement;  and (ii) five million
     (5,000,000)  shares of  Preferred  Stock (with no par  value),  forty-eight
     thousand  thirty-five  (48,035)  of which  have been  designated  "Series A
     Preferred  Stock,"  of which all of such  shares  have been  issued and are
     outstanding as of the date of this  Agreement.  Each  outstanding  share of
     Series A  Preferred  Stock is  convertible  into one  share of Ibex  Common
     Stock.  All of the  outstanding  shares of Ibex  Common  Stock and Series A
     Preferred Stock have been duly authorized and validly issued, and are fully
     paid and  non-assessable.  Part 2.3 of the Disclosure  Schedule provides an
     accurate and complete  description of the terms of each  repurchase  option
     which is held by Ibex and to which any of such shares is subject.

     (b) Ibex has reserved 20,000 shares of Ibex Common Stock for issuance under
     its 1992 Stock Option Plan, of which options to purchase  14,731 shares are
     outstanding  as of the date of this  Agreement.  Part 2.3 of the Disclosure
     Schedule  accurately  sets forth,  with respect to each Ibex Option that is
     outstanding as of the date of this Agreement: (i) the name of the holder of
     such Ibex Option; (ii) the total number of shares of Ibex Common Stock that
     are  subject to such Ibex  Option  and the number of shares of Ibex  Common
     Stock with  respect to which such Ibex Option is  immediately  exercisable;
     (iii) the date on which such Ibex  Option was  granted and the term of such
     Ibex  Option;  (iv) the  vesting  schedule  for such Ibex  Option;  (v) the

                                       17



     exercise price per share of Ibex Common Stock  purchasable  under such Ibex
     Option; and (vi) whether such Ibex Option has been designated an "incentive
     stock option" as defined in Section 422 of the Code. Except as set forth in
     Part  2.3  of  the  Disclosure  Schedule,  there  is  no:  (i)  outstanding
     subscription,  option,  call,  warrant or right  (whether or not  currently
     exercisable) to acquire any shares of the capital stock or other securities
     of Ibex; (ii) outstanding security, instrument or obligation that is or may
     become convertible into or exchangeable for any shares of the capital stock
     or other  securities  of Ibex;  (iii)  Contract  under which Ibex is or may
     become obligated to sell or otherwise issue any shares of its capital stock
     or any other  securities;  or (iv) to the best of the knowledge of Ibex and
     the Designated  Shareholders,  condition or circumstance that may give rise
     to or  provide a basis for the  assertion  of a claim by any  Person to the
     effect  that such  Person is  entitled  to acquire or receive any shares of
     capital stock or other securities of Ibex.

     (c) All  outstanding  shares of Ibex  Common  Stock and Series A  Preferred
     Stock,  and all outstanding  Ibex Options,  have been issued and granted in
     compliance  with (i) all applicable  securities  laws and other  applicable
     Legal  Requirements,  and (ii) all  requirements  set  forth in  applicable
     Contracts.

     (d) Except as set forth in Part 2.3 of the  Disclosure  Schedule,  Ibex has
     never repurchased,  redeemed or otherwise  reacquired any shares of capital
     stock or other  securities  of Ibex.  All  securities so reacquired by Ibex
     were  reacquired in compliance  with (i) the  applicable  provisions of the
     California   General   Corporation  Law  and  all  other  applicable  Legal
     Requirements,  and (ii) all requirements set forth in applicable restricted
     stock purchase agreements and other applicable Contracts.

     2.4 Financial Statements.

     (a) Ibex has delivered to Castelle the following  financial  statements and
     notes (collectively, the "Ibex Financial Statements"):

          (i) The audited  balance  sheets of Ibex as of  December  31, 1995 and
          1994,  and  the  related  audited  income  statements,  statements  of
          shareholders'  equity  and  statements  of cash  flows of Ibex for the
          years then ended,  together with the notes thereto and the unqualified
          report and opinion of Coopers & Lybrand LLP relating thereto; and

          (ii) the  unaudited  balance  sheet of Ibex as of June 30,  1996  (the
          "Unaudited  Interim Balance Sheet"),  and the related unaudited income
          statement of Ibex for the six months then ended.

     (b) Ibex  Financial  Statements  are  accurate and complete in all material
     respects  and  present  fairly  the  financial  position  of Ibex as of the
     respective  dates thereof and the results of operations and (in the case of
     the financial  statements  referred to in Section  2.4(a)(i)) cash flows of
     Ibex for the periods covered thereby.  Ibex Financial  Statements have been
     prepared  in  accordance  with  generally  accepted  accounting  principles
     applied on a consistent  basis  throughout the periods covered (except that

                                       18



     the financial  statements  referred to in Section 2.4(a)(ii) do not contain
     footnotes  and  are  subject  to  normal  and  recurring   year-end   audit
     adjustments,  which will not, individually or in the aggregate, be material
     in magnitude).

     2.5 Absence of Changes.  Except as set forth in Part 2.5 of the  Disclosure
Schedule, since June 30, 1996:

     (a)  there has not been any  material  adverse  change in Ibex's  business,
     condition,  assets,  liabilities,   operations,  financial  performance  or
     prospects,  and, to the best of the  knowledge  of Ibex and the  Designated
     Shareholders,  no event has  occurred  that will,  or could  reasonably  be
     expected to, have a Material Adverse Effect on Ibex;

     (b) there has not been any material loss,  damage or destruction to, or any
     material  interruption  in the use of, any of Ibex's assets (whether or not
     covered by insurance);

     (c) Ibex has not declared,  accrued, set aside or paid any dividend or made
     any other  distribution in respect of any shares of capital stock,  and has
     not  repurchased,  redeemed or otherwise  reacquired  any shares of capital
     stock or other securities;

     (d) Ibex has not sold, issued or authorized the issuance of (i) any capital
     stock or other  security  (except  for Ibex  Common  Stock  issued upon the
     exercise of outstanding Ibex Options),  (ii) any option or right to acquire
     any capital stock or any other security (except for Ibex Options  described
     in  Part  2.3  of  the  Disclosure  Schedule),   or  (iii)  any  instrument
     convertible into or exchangeable for any capital stock or other security;

     (e) Ibex has not amended or waived any of its rights  under,  or  permitted
     the  acceleration  of vesting  under,  (i) any  provision of its 1992 Stock
     Option Plan, (ii) any provision of any agreement evidencing any outstanding
     Ibex Option, or (iii) any restricted stock purchase agreement;

     (f) there has been no  amendment  to Ibex's  articles of  incorporation  or
     bylaws,  and  Ibex  has not  effected  or been a party  to any  Acquisition
     Transaction,  recapitalization,  reclassification  of shares,  stock split,
     reverse stock split or similar transaction;

     (g) Ibex has not formed any  subsidiary or acquired any equity  interest or
     other interest in any other Entity;

     (h) Ibex has not made any  capital  expenditure  which,  when  added to all
     other  capital  expenditures  made on behalf of Ibex since  June 30,  1996,
     exceeds $10,000;

     (i) Ibex has not (i) entered into or  permitted  any of the assets owned or
     used by it to become  bound by any Contract  that is or would  constitute a
     Material  Contract  (as  defined in Section  2.10(a)),  or (ii)  amended or
     prematurely  terminated,  or waived any material right or remedy under, any
     such Contract;

                                       19




     (j) Ibex has not (i) acquired,  leased or licensed any right or other asset
     from any other  Person,  (ii) sold or  otherwise  disposed of, or leased or
     licensed,  any right or other asset to any other Person, or (iii) waived or
     relinquished  any right,  except for immaterial  rights or other immaterial
     assets acquired,  leased, licensed or disposed of in the ordinary course of
     business and consistent with Ibex's past practices;

     (k)  Ibex  has  not  written  off  as  uncollectible,  or  established  any
     extraordinary  reserve  with  respect to, any account  receivable  or other
     indebtedness;

     (l)  Ibex  has not  made  any  pledge  of any of its  assets  or  otherwise
     permitted any of its assets to become  subject to any  Encumbrance,  except
     for pledges of  immaterial  assets made in the ordinary  course of business
     and consistent with Ibex's past practices;

     (m) Ibex has not (i) lent  money to any  Person  (other  than  pursuant  to
     routine  travel  advances  made to  employees  in the  ordinary  course  of
     business),  or (ii) incurred or guaranteed  any  indebtedness  for borrowed
     money;

     (n) Ibex has not (i) established or adopted any Employee Benefit Plan, (ii)
     paid  any  bonus or made any  profit-sharing  or  similar  payment  to,  or
     increased the amount of the wages, salary, commissions,  fringe benefits or
     other  compensation  or  remuneration  payable  to,  any of its  directors,
     officers or employees, or (iii) hired any new employee;

     (o) Ibex has not  changed any of its methods of  accounting  or  accounting
     practices in any respect;

     (p) Ibex has not made any Tax election;

     (q) Ibex has not commenced or settled any Legal Proceeding;

     (r) Ibex has not entered into any material  transaction  or taken any other
     material  action  outside the ordinary  course of business or  inconsistent
     with its past practices; and

     (s) Ibex has not agreed or committed to take any of the actions referred to
     in clauses "(c)" through "(r)" above.

     2.6 Title to Assets.

     (a) Ibex  owns,  and has good,  valid and  marketable  title to, all assets
     purported  to be owned by it,  including:  (i) all assets  reflected on the
     Unaudited  Interim Balance Sheet; (ii) all assets referred to in Parts 2.1,
     2.7, 2.8 and 2.9 of the Disclosure  Schedule and all of Ibex's rights under
     the Contracts identified in Part 2.10 of the Disclosure Schedule; and (iii)
     all other  assets  reflected  in Ibex's books and records as being owned by
     Ibex.  Except as set forth in Part 2.6 of the Disclosure  Schedule,  all of
     said  assets  are  owned  by Ibex  free  and  clear  of any  liens or other

                                       20



     Encumbrances,  except  for (x) any lien for  current  taxes not yet due and
     payable,  and (y) minor  liens that have arisen in the  ordinary  course of
     business  and  that  do not (in any  case or in the  aggregate)  materially
     detract from the value of the assets subject  thereto or materially  impair
     the operations of Ibex.

     (b) Part 2.6 of the  Disclosure  Schedule  identifies  all assets  that are
     material to the  business of Ibex and that are being  leased or licensed to
     Ibex.

     2.7 Bank Accounts; Receivables.

     (a) Part 2.7(a) of the Disclosure  Schedule provides  accurate  information
     with  respect to each account  maintained  by or for the benefit of Ibex at
     any bank or other financial institution.

     (b) Part  2.7(b)  of the  Disclosure  Schedule  provides  an  accurate  and
     complete breakdown and aging of all accounts  receivable,  notes receivable
     and other  receivables of Ibex as of June 30, 1996.  Except as set forth in
     Part 2.7(b) of the Disclosure Schedule, all existing accounts receivable of
     Ibex  (including  those  accounts  receivable  reflected  on the  Unaudited
     Interim  Balance Sheet that have not yet been  collected and those accounts
     receivable  that  have  arisen  since  June 30,  1996 and have not yet been
     collected)  (i) represent  valid  obligations  of customers of Ibex arising
     from  bona  fide  transactions  entered  into  in the  ordinary  course  of
     business, (ii) are current and to the best of the knowledge of Ibex and the
     Designated  Shareholders  will be collected  in full when due,  without any
     counterclaim  or set off (net of an allowance for doubtful  accounts as set
     forth in the Ibex Financial Statements).

     2.8 Equipment; Leasehold.

     (a) All material items of equipment and other  tangible  assets owned by or
     leased to Ibex are  adequate  for the uses to which they are being put, are
     in good  condition  and repair  (ordinary  wear and tear  excepted) and are
     adequate  for the  conduct of Ibex's  business  in the manner in which such
     business is currently being conducted.

     (b) Ibex does not own any real  property or any interest in real  property,
     except for the leasehold  created under the real property lease  identified
     in Part 2.10 of the Disclosure Schedule.

     2.9 Proprietary Assets.

     (a) Part 2.9(a)(i) of the Disclosure  Schedule sets forth,  with respect to
     each Ibex Proprietary  Asset  registered with any Governmental  Body or for
     which an application has been filed with any Governmental Body, (i) a brief
     description  of  such  Proprietary   Asset,  and  (ii)  the  names  of  the
     jurisdictions covered by the applicable  registration or application.  Part
     2.9(a)(ii)  of the  Disclosure  Schedule  identifies  and  provides a brief
     description  of all  other  Ibex  Proprietary  Assets  owned by Ibex.  Part
     2.9(a)(iii)  of the  Disclosure  Schedule  identifies  and provides a brief
     description  of each  Proprietary  Asset  licensed  to  Ibex by any  Person

                                       21


     (except for any Proprietary  Asset that is licensed to Ibex under any third
     party software license generally  available to the public at a cost of less
     than  $10,000),  and  identifies  the  license  agreement  under which such
     Proprietary  Asset is being  licensed to Ibex.  Except as set forth in Part
     2.9(a)(iv) of the Disclosure Schedule,  Ibex has good, valid and marketable
     title to all of Ibex Proprietary  Assets  identified in Parts 2.9(a)(i) and
     2.9(a)(ii)  of the  Disclosure  Schedule,  free and  clear of all liens and
     other  Encumbrances,  and has a valid right to use all  Proprietary  Assets
     identified in Part  2.9(a)(iii) of the Disclosure  Schedule.  Except as set
     forth in Part 2.9(a)(v) of the Disclosure  Schedule,  Ibex is not obligated
     to make any  payment  to any  Person  for the use of any  Ibex  Proprietary
     Asset.  Except as set forth in Part 2.9(a)(vi) of the Disclosure  Schedule,
     Ibex has not developed  jointly with any other Person any Ibex  Proprietary
     Asset with respect to which such other Person has any rights.

     (b) Ibex has taken all  reasonable  measures and  precautions  necessary to
     protect  and  maintain  the   confidentiality   and  secrecy  of  all  Ibex
     Proprietary  Assets  (except Ibex  Proprietary  Assets whose value would be
     unimpaired by public  disclosure) and otherwise to maintain and protect the
     value of all Ibex Proprietary Assets. Except as set forth in Part 2.9(b) of
     the  Disclosure  Schedule,  to the  best of the  knowledge  of Ibex and the
     Designated  Shareholders  after inquiry of Ibex's  officers,  directors and
     advisors,   Ibex  has  not  (other  than  pursuant  to  license  agreements
     identified in Part 2.10 of the Disclosure  Schedule) disclosed or delivered
     to any Person,  or permitted  the  disclosure or delivery to any Person of,
     (i) the source code,  or any portion or aspect of the source  code,  of any
     Ibex  Proprietary  Asset, or (ii) the object code, or any portion or aspect
     of the object code, of any Ibex Proprietary Asset.

     (c) To the best of the  knowledge of Ibex and the  Designated  Shareholders
     after inquiry of Ibex's  officers,  directors  and  advisors,  none of Ibex
     Proprietary  Assets infringes or conflicts with any Proprietary Asset owned
     or used by any other  Person.  To the best of the knowledge of Ibex and the
     Designated  Shareholders  after inquiry of Ibex's  officers,  directors and
     advisors,  Ibex is not infringing,  misappropriating or making any unlawful
     use of, and Ibex has not at any time infringed, misappropriated or made any
     unlawful use of, or received any notice or other  communication (in writing
     or otherwise) of any actual,  alleged,  possible or potential infringement,
     misappropriation or unlawful use of, any Proprietary Asset owned or used by
     any other Person.  To the best of the knowledge of Ibex and the  Designated
     Shareholders, no other Person is infringing, misappropriating or making any
     unlawful use of, and no Proprietary Asset owned or used by any other Person
     infringes or conflicts with, any Ibex Proprietary Asset.

     (d) Except as set forth in Part 2.9(d) of the Disclosure Schedule: (i) each
     Ibex  Proprietary   Asset  conforms  in  all  material  respects  with  any
     specification,   documentation,  performance  standard,  representation  or
     statement  made or provided  with respect  thereto by or on behalf of Ibex;
     and (ii)  there  has not been any  claim by any  customer  or other  Person
     alleging that any Ibex  Proprietary  Asset  (including each version thereof
     that has ever been  licensed or  otherwise  made  available  by Ibex to any
     Person) does not conform in all material  respects with any  specification,
     documentation,  performance  standard,  representation or statement made or
     provided by or on behalf of Ibex, and, to the best of the knowledge of Ibex
     and the Designated Shareholders, there is no basis for any such claim. Ibex
     has established adequate reserves on the Unaudited Interim Balance Sheet to

                                       22


     cover all costs  associated  with any  obligations  that Ibex may have with
     respect to the correction or repair of programming  errors or other defects
     in Ibex Proprietary Assets.

     (e) Ibex Proprietary Assets constitute all the Proprietary Assets necessary
     to enable Ibex to conduct its business in the manner in which such business
     has been and is being conducted.  Except as set forth in Part 2.9(e) of the
     Disclosure  Schedule,  (i) Ibex has not  licensed  any of Ibex  Proprietary
     Assets to any Person on an exclusive  basis,  and (ii) Ibex has not entered
     into any  covenant  not to  compete or  Contract  limiting  its  ability to
     exploit fully any of its Proprietary  Assets or to transact business in any
     market or geographical area or with any Person.

     (f) Except as set forth in Part 2.9(f) of the Disclosure Schedule,  (i) all
     current and former employees of Ibex have executed and delivered to Ibex an
     agreement  (containing no exceptions to or exclusions from the scope of its
     coverage)  that is  substantially  identical  to the  form of  Confidential
     Information  and Invention  Assignment  Agreement  previously  delivered to
     Castelle,  and (ii) all  current  and former  consultants  and  independent
     contractors  to Ibex  have  executed  and  delivered  to Ibex an  agreement
     (containing no exceptions to or exclusions  from the scope of its coverage)
     that is substantially  identical to the standard form of proprietary rights
     agreement previously delivered to Castelle.

     2.10 Contracts.

     (a) Part 2.10 of the Disclosure Schedule identifies:

          (i)  each  Ibex  Contract  relating  to  the  employment  of,  or  the
          performance  of services by, any employee,  consultant or  independent
          contractor;

          (ii) each Ibex Contract  relating to the acquisition,  transfer,  use,
          development,  sharing or license of any technology or any  Proprietary
          Asset;

          (iii) each Ibex Contract  imposing any  restriction on Ibex's right or
          ability  (A) to compete  with any other  Person,  (B) to  acquire  any
          product or other asset or any services from any other Person,  to sell
          any product or other asset to or perform  any  services  for any other
          Person or to transact  business  or deal in any other  manner with any
          other Person, or (C) develop or distribute any technology;

          (iv) each Ibex Contract creating or involving any agency relationship,
          distribution arrangement or franchise relationship;

          (v) each  Ibex  Contract  relating  to the  acquisition,  issuance  or
          transfer of any securities;

          (vi) each Ibex  Contract  relating to the creation of any  Encumbrance
          with respect to any asset of Ibex;

                                       23



          (vii) each Ibex Contract involving or incorporating any guaranty,  any
          pledge,  any  performance  or  completion  bond,  any indemnity or any
          surety arrangement;

          (viii) each Ibex Contract  creating or relating to any  partnership or
          joint venture or any sharing of revenues,  profits,  losses,  costs or
          liabilities;

          (ix)  each  Ibex  Contract  relating  to the  purchase  or sale of any
          product or other asset by or to, or the performance of any services by
          or for, any Related Party (as defined in Section 2.18);

          (x) each  Ibex  Contract  constituting  or  relating  to a  Government
          Contract or Government Bid;

          (xi) any  other  Ibex  Contract  that was  entered  into  outside  the
          ordinary  course of  business  or was  inconsistent  with  Ibex's past
          practices;

          (xii) any other Ibex Contract that has a term of more than 60 days and
          that may not be terminated by Ibex  (without  penalty)  within 60 days
          after the delivery of a termination notice by Ibex; and

          (xiii) any other Ibex Contract that  contemplates  or involves (A) the
          payment or  delivery  of cash or other  consideration  in an amount or
          having a value in  excess  of  $10,000  in the  aggregate,  or (B) the
          performance  of  services  having a value in excess of  $10,000 in the
          aggregate.

(Contracts  in the  respective  categories  described in clauses  "(i)"  through
"(xiii)" above are referred to in this Agreement as "Material Contracts.")

     (b) Ibex has  delivered to Castelle  accurate  and  complete  copies of all
     written  Contracts  identified  in Part  2.10 of the  Disclosure  Schedule,
     including all  amendments  thereto.  Part 2.10 of the  Disclosure  Schedule
     provides an accurate description of the terms of each Ibex Contract that is
     not  in  written  form.  Each  Contract  identified  in  Part  2.10  of the
     Disclosure Schedule is valid and in full force and effect, and, to the best
     of the knowledge of Ibex and the Designated Shareholders, is enforceable by
     Ibex  in  accordance  with  its  terms,  subject  to (i)  laws  of  general
     application  relating to bankruptcy,  insolvency and the relief of debtors,
     and (ii) rules of law governing specific performance, injunctive relief and
     other equitable remedies.

     (c) Except as set forth in Part 2.10 of the Disclosure Schedule:

          (i) Ibex has not violated or breached, or committed any default under,
          any Ibex  Contract,  and, to the best of the knowledge of Ibex and the
          Designated Shareholders,  no other Person has violated or breached, or
          committed any default under, any Ibex Contract;

                                       24



          (ii)  to  the  best  of the  knowledge  of  Ibex  and  the  Designated
          Shareholders,  no event has occurred, and no circumstance or condition
          exists,  that (with or without notice or lapse of time) will, or could
          reasonably  be expected to, (A) result in a violation or breach of any
          of the provisions of any Ibex Contract,  (B) give any Person the right
          to declare a default or exercise any remedy  under any Ibex  Contract,
          (C)  give  any  Person  the  right  to  accelerate   the  maturity  or
          performance of any Ibex Contract,  or (D) give any Person the right to
          cancel, terminate or modify any Ibex Contract;

          (iii) since  December  31,  1992,  Ibex has not received any notice or
          other  communication  regarding  any actual or possible  violation  or
          breach of, or default under, any Ibex Contract; and

          (iv) Ibex has not waived any of its material rights under any Material
          Contract.

     (d) No Person is renegotiating, or has a right pursuant to the terms of any
     Ibex Contract to renegotiate,  any amount paid or payable to Ibex under any
     Material  Contract or any other  material term or provision of any Material
     Contract.

     (e) The  Contracts  identified  in Part  2.10  of the  Disclosure  Schedule
     collectively  constitute  all of the Contracts  necessary to enable Ibex to
     conduct its business in the manner in which its business is currently being
     conducted.

     (f) Part 2.10 of the  Disclosure  Schedule  identifies and provides a brief
     description of each proposed  Contract as to which any bid,  offer,  award,
     written  proposal,  term sheet or similar  document  has been  submitted or
     received by Ibex since January 1, 1996.

     (g) Part 2.10 of the Disclosure  Schedule provides an accurate  description
     and breakdown of Ibex's backlog under Ibex Contracts.

     (h) Except as set forth in Part 2.10(h) of the  Disclosure  Schedule,  Ibex
     has not entered  into and is not  negotiating  any  Government  Contract or
     Government Bid, and Ibex is not and will not be required to make any filing
     with or give any notice to, or to obtain any Consent from, any Governmental
     Body under or in connection with any Government  Contract or Government Bid
     as a result of or by virtue of (A) the  execution,  delivery of performance
     of  this  Agreement  or any of the  other  agreements  referred  to in this
     Agreement,  or (B)  the  consummation  of the  Merger  or any of the  other
     transactions contemplated by this Agreement.

     2.11 Liabilities.  Ibex has no accrued,  contingent or other liabilities of
any nature, either matured or unmatured (whether or not required to be reflected
in  financial  statements  in  accordance  with  generally  accepted  accounting
principles,  and whether due or to become  due),  except  for:  (a)  liabilities
identified as such in the "liabilities"  column of the Unaudited Interim Balance
Sheet;  (b) accounts payable or accrued salaries that have been incurred by Ibex
since June 30, 1996 in the  ordinary  course of  business  and  consistent  with
Ibex's past practices;  (c) liabilities under Ibex Contracts  identified in Part

                                       25



2.10 of the Disclosure Schedule,  to the extent the nature and magnitude of such
liabilities  can be  specifically  ascertained  by reference to the text of such
Ibex  Contracts;  and  (d)  the  liabilities  identified  in  Part  2.11  of the
Disclosure Schedule.

     2.12  Compliance with Legal  Requirements.  To the best of the knowledge of
Ibex and the  Designated  Shareholders,  Ibex  is,  and has at all  times  since
December 31, 1992 been, in compliance  with all applicable  Legal  Requirements,
except where the failure to comply with such Legal  Requirements has not had and
will not have a  Material  Adverse  Effect on Ibex.  Except as set forth in Part
2.12 of the Disclosure Schedule,  since December 31, 1992, Ibex has not received
any notice or other  communication  from any  Governmental  Body  regarding  any
actual  or  possible  violation  of,  or  failure  to  comply  with,  any  Legal
Requirement.

     2.13  Governmental  Authorizations.  Part 2.13 of the  Disclosure  Schedule
identifies each material  Governmental  Authorization held by Ibex, and Ibex has
delivered  to  Castelle   accurate  and  complete  copies  of  all  Governmental
Authorizations   identified  in  Part  2.13  of  the  Disclosure  Schedule.  The
Governmental  Authorizations  identified in Part 2.13 of the Disclosure Schedule
are  valid  and in full  force  and  effect,  and  collectively  constitute  all
Governmental  Authorizations necessary to enable Ibex to conduct its business in
the manner in which its business is currently being  conducted.  Ibex is, and at
all times since December 31, 1992 has been, in substantial  compliance  with the
material terms and  requirements of the respective  Governmental  Authorizations
identified in Part 2.13 of the  Disclosure  Schedule.  Since  December 31, 1992,
Ibex has not received any notice or other  communication  from any  Governmental
Body regarding (a) any actual or possible violation of or failure to comply with
any term or requirement of any Governmental Authorization,  or (b) any actual or
possible  revocation,  withdrawal,  suspension,  cancellation,   termination  or
modification of any Governmental Authorization.

     2.14 Tax Matters.

     (a) All Tax  Returns  required to be filed by or on behalf of Ibex with any
     Governmental  Body with respect to any taxable  period  ending on or before
     the Closing Date (the "Ibex  Returns") (i) have been or will be filed on or
     before the applicable due date (including any extensions of such due date),
     and (ii)  have  been,  or will be when  filed,  accurately  and  completely
     prepared in all material  respects in compliance with all applicable  Legal
     Requirements.  All amounts shown on Ibex Returns to be due on or before the
     Closing Date have been or will be paid on or before the Closing Date.  Ibex
     has delivered to Castelle  accurate and complete copies of all Ibex Returns
     filed since December 31, 1992 which have been requested by Castelle.

     (b) Ibex  Financial  Statements  fully  accrue all  actual  and  contingent
     liabilities for Taxes with respect to all periods through the dates thereof
     in accordance  with generally  accepted  accounting  principles.  Ibex will
     establish,  in the ordinary course of business and consistent with its past
     practices,  reserves  adequate  for the payment of all Taxes for the period
     from June 30, 1996  through the Closing  Date,  and Ibex will  disclose the
     dollar amount of such reserves to Castelle on or prior to the Closing Date.

                                       26



     (c) No Ibex  Return  relating  to income  Taxes has ever been  examined  or
     audited by any Governmental  Body.  Except as set forth in Part 2.14 of the
     Disclosure Schedule,  there have been no examinations or audits of any Ibex
     Return.  Ibex has delivered to Castelle accurate and complete copies of all
     audit reports and similar  documents (to which Ibex has access) relating to
     Ibex Returns.  Except as set forth in Part 2.14 of the Disclosure Schedule,
     no extension or waiver of the limitation  period  applicable to any of Ibex
     Returns  has  been  granted  (by  Ibex or any  other  Person),  and no such
     extension or waiver has been requested from Ibex.

     (d) Except as set forth in Part 2.14 of the Disclosure  Schedule,  no claim
     or Proceeding is pending or has been threatened  against or with respect to
     Ibex in respect of any Tax. There are no unsatisfied  liabilities for Taxes
     (including liabilities for interest, additions to tax and penalties thereon
     and related  expenses)  with respect to any notice of deficiency or similar
     document  received by Ibex with respect to any Tax (other than  liabilities
     for Taxes asserted under any such notice of deficiency or similar  document
     which are being  contested  in good faith by Ibex and with respect to which
     adequate  reserves for payment have been  established).  There are no liens
     for Taxes upon any of the assets of Ibex except liens for current Taxes not
     yet due and  payable.  Ibex has not  entered  into or  become  bound by any
     agreement or consent  pursuant to Section 341(f) of the Code.  Ibex has not
     been,  and Ibex will not be,  required to include any adjustment in taxable
     income for any tax period (or portion  thereof)  pursuant to Section 481 or
     263A of the Code or any  comparable  provision  under  state or foreign Tax
     laws as a result of transactions or events occurring, or accounting methods
     employed, prior to the Closing.

     (e) There is no agreement, plan, arrangement or other Contract covering any
     employee  or  independent  contractor  or former  employee  or  independent
     contractor of Ibex that, considered individually or considered collectively
     with any other such  Contracts,  will, or could  reasonably be expected to,
     give rise  directly or  indirectly  to the payment of any amount that would
     not be deductible pursuant to Section 280G or Section 162 of the Code. Ibex
     is not,  and has  never  been,  a party to or  bound  by any tax  indemnity
     agreement,  tax sharing  agreement,  tax  allocation  agreement  or similar
     Contract.

     2.15 Employee and Labor Matters; Benefit Plans.

     (a) Part 2.15(a) of the Disclosure Schedule identifies each salary,  bonus,
     deferred  compensation,   incentive  compensation,  stock  purchase,  stock
     option, severance pay, termination pay,  hospitalization,  medical, life or
     other  insurance,   supplemental  unemployment  benefits,   profit-sharing,
     pension  or  retirement  plan,  program  or  agreement  (collectively,  the
     "Plans")   sponsored,   maintained,   contributed  to  or  required  to  be
     contributed   to  by  Ibex  for  the  benefit  of  any   employee  of  Ibex
     ("Employee"),  except  for  Plans  which  would  not  require  Ibex to make
     payments  or  provide  benefits  having a value in excess of $10,000 in the
     aggregate.

     (b) Except as set forth in Part 2.15(a) of the  Disclosure  Schedule,  Ibex
     does not  maintain,  sponsor  or  contribute  to,  and,  to the best of the
     knowledge of Ibex and the Designated  Shareholders,  has not at any time in

                                       27


     the past  maintained,  sponsored or  contributed  to, any employee  pension
     benefit plan (as defined in Section 3(2) of the Employee  Retirement Income
     Security Act of 1974,  as amended  ("ERISA"),  whether or not excluded from
     coverage  under  specific  Titles or  Merger  Subtitles  of ERISA)  for the
     benefit of Employees or former Employees (a "Pension Plan").

     (c) Ibex maintains,  sponsors or contributes only to those employee welfare
     benefit plans (as defined in Section 3(1) of ERISA, whether or not excluded
     from coverage under specific  Titles or Merger  Subtitles of ERISA) for the
     benefit  of  Employees  or former  Employees  which are  described  in Part
     2.15(c) of the Disclosure Schedule (the "Welfare Plans"),  none of which is
     a multiemployer plan (within the meaning of Section 3(37) of ERISA).

     (d) With respect to each Plan, Ibex has delivered to Castelle:

          (i) an  accurate  and  complete  copy  of  such  Plan  (including  all
          amendments thereto);

          (ii) an accurate and complete copy of the annual  report,  if required
          under ERISA, with respect to such Plan for the last two years;

          (iii) an accurate  and complete  copy of the most recent  summary plan
          description,  together with each Summary of Material Modifications, if
          required  under  ERISA,  with  respect to such Plan,  and all material
          employee communications relating to such Plan;

          (iv) if such Plan is funded through a trust or any third party funding
          vehicle,  an accurate and complete  copy of the trust or other funding
          agreement (including all amendments thereto) and accurate and complete
          copies the most recent financial statements thereof;

          (v)  accurate and complete  copies of all  Contracts  relating to such
          Plan,  including  service provider  agreements,  insurance  contracts,
          minimum premium contracts, stop-loss agreements, investment management
          agreements,    subscription   and    participation    agreements   and
          recordkeeping agreements; and

          (vi) an accurate  and complete  copy of the most recent  determination
          letter received from the Internal Revenue Service with respect to such
          Plan (if such Plan is intended to be qualified under Section 401(a) of
          the Code).

     (e) Ibex is not  required to be, and, to the best of the  knowledge of Ibex
     and the Designated Shareholders,  has never been required to be, treated as
     a single  employer with any other Person under Section  4001(b)(1) of ERISA
     or  Section  414(b),  (c),  (m) or (o) of the Code.  Ibex has never  been a
     member of an  "affiliated  service  group"  within  the  meaning of Section
     414(m) of the Code. To the best of the knowledge of Ibex and the Designated
     Shareholders,  Ibex has never made a complete or partial  withdrawal from a
     multiemployer  plan,  as such term is defined  in  Section  3(37) of ERISA,

                                       28


     resulting  in  "withdrawal  liability,"  as such term is defined in Section
     4201 of ERISA  (without  regard to  subsequent  reduction or waiver of such
     liability under either Section 4207 or 4208 of ERISA).

     (f) Ibex  does not have any plan or  commitment  to create  any  additional
     Welfare  Plan or any  Pension  Plan,  or to modify or change  any  existing
     Welfare Plan or Pension Plan (other than to comply with  applicable law) in
     a manner that would affect any Employee.

     (g) Except as set forth in Part  2.15(g)  of the  Disclosure  Schedule,  no
     Welfare Plan provides  death,  medical or health  benefits  (whether or not
     insured)  with  respect to any  current or former  Employee  after any such
     Employee's termination of service (other than (i) benefit coverage mandated
     by applicable law, including coverage provided pursuant to Section 4980B of
     the Code, (ii) deferred compensation benefits accrued as liabilities on the
     Unaudited  Interim Balance Sheet, and (iii) benefits the full cost of which
     are   borne  by   current   or   former   Employees   (or  the   Employees'
     beneficiaries)).

     (h) With respect to each of the Welfare Plans  constituting  a group health
     plan within the meaning of Section  4980B(g)(2) of the Code, the provisions
     of  Section  4980B of the Code  ("COBRA")  have been  complied  with in all
     material respects.

     (i) Each of the Plans has been  operated and  administered  in all material
     respects in accordance with applicable  Legal  Requirements,  including but
     not limited to ERISA and the Code.

     (j) Each of the Plans intended to be qualified  under Section 401(a) of the
     Code has  received a  favorable  determination  from the  Internal  Revenue
     Service,  and neither Ibex nor any of the Designated  Shareholders is aware
     of any reason why any such determination letter should be revoked.

     (k) Except as set forth in Part 2.15(k) of the Disclosure Schedule, neither
     the  execution,   delivery  or  performance  of  this  Agreement,  nor  the
     consummation of the Merger or any of the other transactions contemplated by
     this  Agreement,  will result in any payment  (including any bonus,  golden
     parachute  or  severance  payment)  to any  current or former  Employee  or
     director of Ibex (whether or not under any Plan),  or  materially  increase
     the benefits  payable under any Plan, or result in any  acceleration of the
     time of payment or vesting of any such benefits.

     (l) Part 2.15(l) of the Disclosure Schedule contains a list of all salaried
     employees of Ibex as of the date of this Agreement, and correctly reflects,
     in all material respects, their salaries, any other compensation payable to
     them  (including   compensation   payable   pursuant  to  bonus,   deferred
     compensation  or commission  arrangements),  their dates of employment  and
     their positions.  Ibex is not a party to any collective bargaining contract
     or other Contract with a labor union involving any of its Employees. All of
     Ibex's employees are "at will" employees.

                                       29



     (m) Part 2.15(m) of the Disclosure Schedule identifies each Employee who is
     not fully  available to perform work because of  disability  or other leave
     and sets forth the basis of such leave and the  anticipated  date of return
     to full service.

     (n) Ibex is in  compliance  in all material  respects  with all  applicable
     Legal  Requirements  and  Contracts  relating  to  employment,   employment
     practices, wages, bonuses and terms and conditions of employment, including
     employee compensation matters.

     (o) Except as set forth in Part 2.15(o) of the  Disclosure  Schedule,  Ibex
     has good labor relations,  and none of the Designated  Shareholders has any
     reason to  believe  that (i) the  consummation  of the Merger or any of the
     other  transactions  contemplated  by this  Agreement  will have a material
     adverse effect on Ibex's labor  relations,  or (ii) any of Ibex's employees
     intends to terminate his or her employment with Ibex.

     2.16 Environmental  Matters. Ibex is in compliance in all material respects
with all applicable Environmental Laws, which compliance includes the possession
by Ibex of all  permits and other  Governmental  Authorizations  required  under
applicable  Environmental  Laws,  and  compliance  with the terms and conditions
thereof.  Ibex has not received any notice or other communication (in writing or
otherwise),  whether  from a  Governmental  Body,  citizens  group,  employee or
otherwise,  that alleges that Ibex is not in compliance  with any  Environmental
Law,  and, to the best of the  knowledge  of Ibex and  Designated  Shareholders,
there are no circumstances  that may prevent or interfere with Ibex's compliance
with any  Environmental  Law in the future. To the best of the knowledge of Ibex
and the  Designated  Shareholders,  no  current or prior  owner of any  property
leased or controlled by Ibex has received any notice or other  communication (in
writing or otherwise),  whether from a Government Body, citizens group, employee
or  otherwise,  that  alleges that such current or prior owner or Ibex is not in
compliance with any Environmental Law. All Governmental Authorizations currently
held by Ibex pursuant to  Environmental  Laws are identified in Part 2.16 of the
Disclosure Schedule. (For purposes of this Section 2.16: (i) "Environmental Law"
means any  federal,  state,  local or  foreign  Legal  Requirement  relating  to
pollution or protection of human health or the  environment  (including  ambient
air, surface water, ground water, land surface or subsurface strata),  including
any law or regulation relating to emissions,  discharges, releases or threatened
releases of Materials of  Environmental  Concern,  or otherwise  relating to the
manufacture,   processing,  distribution,  use,  treatment,  storage,  disposal,
transport or handling of Materials of Environmental Concern; and (ii) "Materials
of Environmental Concern" include chemicals, pollutants,  contaminants,  wastes,
toxic substances,  petroleum and petroleum products and any other substance that
is now  regulated  by any  Environmental  Law or that is  otherwise  a danger to
health, reproduction or the environment.)

     2.17  Insurance.  Part  2.17  of the  Disclosure  Schedule  identifies  all
insurance  policies  maintained by, at the expense of or for the benefit of Ibex
and identifies any material  claims made  thereunder,  and Ibex has delivered to
Castelle  accurate and complete copies of the insurance  policies  identified on
Part 2.17 of the Disclosure Schedule.  Each of the insurance policies identified
in Part 2.17 of the  Disclosure  Schedule  is in full  force and  effect.  Since

                                       30



December  31,  1992,  Ibex has not  received  any notice or other  communication
regarding  any  actual or  possible  (a)  cancellation  or  invalidation  of any
insurance  policy,  (b) refusal of any  coverage or rejection of any claim under
any insurance policy,  or (c) material  adjustment in the amount of the premiums
payable with respect to any insurance policy.

     2.18 Related  Party  Transactions.  Except as set forth in Part 2.18 of the
Disclosure  Schedule:  (a) no Related Party has, and no Related Party has at any
time since  December  31,  1992 had,  any  direct or  indirect  interest  in any
material  asset used in or otherwise  relating to the  business of Ibex;  (b) no
Related Party is, or has at any time since  December 31, 1992 been,  indebted to
Ibex; (c) since December 31, 1992, no Related Party has entered into, or has had
any direct or indirect financial interest in, any material Contract, transaction
or business dealing involving Ibex; (d) no Related Party is competing, or has at
any time since  December 31, 1992 competed,  directly or indirectly,  with Ibex;
and (e) no Related  Party has any claim or right against Ibex (other than rights
under company Options and rights to receive  compensation for services performed
as an employee of Ibex). (For purposes of the Section 2.18 each of the following
shall  be  deemed  to  be  a  "Related  Party":   (i)  each  of  the  Designated
Shareholders; (ii) each individual who is, or who has at any time since December
31, 1992 been, an officer of Ibex;  (iii) each member of the immediate family of
each of the individuals  referred to in clauses "(i)" and "(ii)" above; and (iv)
any trust or other Entity (other than Ibex) in which any one of the  individuals
referred to in clauses  "(i)",  "(ii)" and "(iii)" above holds (or in which more
than one of such individuals  collectively hold),  beneficially or otherwise,  a
material voting, proprietary or equity interest.)

     2.19 Legal Proceedings; Orders.

     (a) Except as set forth in Part 2.19 of the Disclosure  Schedule,  there is
     no pending Legal Proceeding,  and (to the best of the knowledge of Ibex and
     the Designated Shareholders) no Person has threatened to commence any Legal
     Proceeding:  (i) that  involves  Ibex or any of the assets owned or used by
     Ibex or any  Person  whose  liability  Ibex  has or may  have  retained  or
     assumed,  either  contractually  or by  operation  of  law;  or  (ii)  that
     challenges,  or that may have the effect of  preventing,  delaying,  making
     illegal  or  otherwise  interfering  with,  the  Merger or any of the other
     transactions  contemplated by this Agreement.  To the best of the knowledge
     of Ibex and the Designated  Shareholders,  except as set forth in Part 2.19
     of the Disclosure Schedule, no event has occurred, and no claim, dispute or
     other condition or circumstance exists, that will, or that could reasonably
     be expected  to, give rise to or serve as a basis for the  commencement  of
     any such Legal Proceeding.

     (b) Except as set forth in Part 2.19 of the Disclosure  Schedule,  no Legal
     Proceeding  has ever been  commenced  by or has ever been  pending  against
     Ibex.

     (c) There is no order, writ, injunction,  judgment or decree to which Ibex,
     or any of the  assets  owned  or  used by  Ibex,  is  subject.  None of the
     Designated Shareholders is subject to any order, writ, injunction, judgment
     or decree that relates to Ibex's  business or to any of the assets owned or
     used by Ibex.  To the  best of the  knowledge  of Ibex  and the  Designated
     Shareholders, no officer or other employee of Ibex is subject to any order,

                                       31


     writ,  injunction,  judgment or decree that prohibits such officer or other
     employee from engaging in or continuing  any conduct,  activity or practice
     relating to Ibex's business.

     2.20 Authority;  Binding Nature of Agreement. Ibex has the right, power and
authority to enter into and to perform its obligations under this Agreement; and
the execution, delivery and performance by Ibex of this Agreement have been duly
authorized  by all  necessary  action  on the  part of Ibex  and  its  board  of
directors. This Agreement constitutes the legal, valid and binding obligation of
Ibex, enforceable against Ibex in accordance with its terms, subject to (i) laws
of general  application  relating to  bankruptcy,  insolvency  and the relief of
debtors, and (ii) rules of law governing specific performance, injunctive relief
and other equitable remedies.

     2.21 Non-Contravention;  Consents.  Except as set forth in Part 2.21 of the
Disclosure Schedule, neither (1) the execution,  delivery or performance of this
Agreement or any of the other agreements referred to in this Agreement,  nor (2)
the consummation of the Merger or any of the other transactions  contemplated by
this Agreement,  will directly or indirectly (with or without notice or lapse of
time):

     (a)  contravene,  conflict  with or result in a violation of (i) any of the
     provisions  of Ibex's  articles  of  incorporation  or bylaws,  or (ii) any
     resolution adopted by Ibex's shareholders, Ibex's board of directors or any
     committee of Ibex's board of directors;

     (b)  contravene,  conflict  with or result in a  violation  of, or give any
     Governmental  Body or  other  Person  the  right  to  challenge  any of the
     transactions  contemplated  by this  Agreement or to exercise any remedy or
     obtain  any  relief  under,  any  Legal  Requirement  or any  order,  writ,
     injunction, judgment or decree to which Ibex, or any of the assets owned or
     used by Ibex, is subject;

     (c) contravene,  conflict with or result in a violation of any of the terms
     or  requirements  of, or give any  Governmental  Body the right to  revoke,
     withdraw,   suspend,   cancel,   terminate  or  modify,   any  Governmental
     Authorization  that is held by Ibex or that  otherwise  relates  to  Ibex's
     business or to any of the assets owned or used by Ibex;

     (d)  contravene,  conflict  with or result in a violation  or breach of, or
     result in a material default under, any provision of any Ibex Contract that
     is or would constitute a Material Contract, or give any Person the right to
     (i) declare a default or exercise any remedy under any such Ibex  Contract,
     (ii)  accelerate the maturity or performance of any such Ibex Contract,  or
     (iii) cancel, terminate or modify any such Ibex Contract; or

     (e) result in the  imposition or creation of any lien or other  Encumbrance
     upon or with  respect to any asset owned or used by Ibex  (except for minor
     liens that will not, in any case or in the  aggregate,  materially  detract
     from the value of the  assets  subject  thereto  or  materially  impair the
     operations of Ibex).

                                       32



Except  as set forth in Part 2.21 of the  Disclosure  Schedule,  Ibex is not and
will not be required to make any filing with or give any notice to, or to obtain
any Consent from, any Person in connection  with (x) the execution,  delivery or
performance of this Agreement or any of the other agreements referred to in this
Agreement,  or  (y)  the  consummation  of  the  Merger  or  any  of  the  other
transactions contemplated by this Agreement.

     2.22 Full Disclosure.

     (a) This Agreement  (including  the Disclosure  Schedule) does not, and the
     Designated  Shareholders'  Closing  Certificate  will not,  (i) contain any
     representation,  warranty or information  that is false or misleading  with
     respect  to any  material  fact,  or (ii) omit to state any  material  fact
     necessary in order to make the representations,  warranties and information
     contained  and to be  contained  herein  and  therein  (in the light of the
     circumstances under which such representations,  warranties and information
     were or will be made or provided) not false or misleading.

     (b) Should Castelle elect to file a permit  application under Section 25121
     of the California Corporations Code, including an Information Statement (as
     defined in Section 5.2), the information  supplied by Ibex for inclusion in
     the  Information  Statement  will  not,  as of the date of the  Information
     Statement or as of the date of the Ibex  Shareholders'  Meeting (as defined
     in Section 5.3), (i) contain any statement that is inaccurate or misleading
     with respect to any material  fact, or (ii) omit to state any material fact
     necessary  in  order  to  make  such  information  (in  the  light  of  the
     circumstances under which it is provided) not false or misleading.

     (c) Should  Castelle elect to prepare and file a registration  statement on
     Form  S-4 to be filed  with  the SEC by  Castelle  in  connection  with the
     issuance of the Castelle Common Stock in the Merger (the "S-4  Registration
     Statement"), none of the information supplied or to be supplied by Ibex for
     inclusion or incorporation  by reference in the S-4 Registration  Statement
     will, at the time the S-4  Registration  Statement is filed with the SEC or
     at the time the S-4  Registration  Statement  becomes  effective  under the
     Securities Act,  contain any untrue statement of a material fact or omit to
     state any material fact required to be stated therein or necessary in order
     to make the statements  therein,  in light of the circumstances under which
     they are made, not misleading.  None of the  information  supplied or to be
     supplied  by Ibex  for  inclusion  or  incorporation  by  reference  in the
     Prospectus/Proxy  Statement  filed  as  a  part  of  the  S-4  Registration
     Statement (the "Prospectus/Proxy  Statement"),  will, at the time mailed to
     the  shareholders  of  Castelle  and Ibex,  and as of the  Effective  Time,
     contain  any  untrue  statement  of a  material  fact or omit to state  any
     material fact  required to be stated  therein or necessary in order to make
     the statements  therein, in light of the circumstances under which they are
     made, not misleading.

SECTION 3. REPRESENTATIONS AND WARRANTIES OF CASTELLE

     Castelle represents and warrants to Ibex and the Designated Shareholders as
follows:

                                       33


     3.1 Due Organization; No Subsidiaries; Etc.

     (a) Castelle is a corporation duly organized,  validly existing and in good
     standing  under the laws of the State of  California  and has all necessary
     power and authority: (i) to conduct its business in the manner in which its
     business is currently  being  conducted;  (ii) to own and use its assets in
     the manner in which its assets are currently  owned and used;  and (iii) to
     perform its obligations under all Castelle Contracts.

     (b) Except as set forth in Part 3.1 of the  Castelle  Disclosure  Schedule,
     Castelle has not conducted any business  under or otherwise  used,  for any
     purpose or in any  jurisdiction,  any fictitious name,  assumed name, trade
     name or other name, other than the name "Castelle."

     (c) Castelle is not and has not been required to be qualified,  authorized,
     registered  or  licensed to do  business  as a foreign  corporation  in any
     jurisdiction where the failure to be so qualified,  authorized,  registered
     or  licensed  has not had and will not have a  Material  Adverse  Effect on
     Castelle.

     (d)  Castelle's   Form  10-KSB  filed  with  the  Securities  and  Exchange
     Commission  (the "SEC") on April 1, 1996 and its Form  10-KSB/A  filed with
     the SEC on April  29,  1996  accurately  sets  forth  (i) the  names of the
     members of Castelle's board of directors,  (ii) the names of the members of
     each  committee of Castelle's  board of directors,  and (iii) the names and
     titles of Castelle's officers.

     (e)  Castelle  does not own any  controlling  interest  in any Entity  and,
     except  for the equity  interests  identified  in Part 3.1 of the  Castelle
     Disclosure Schedule,  Castelle has never owned,  beneficially or otherwise,
     any  shares or other  securities  of,  or any  direct  or  indirect  equity
     interest in, any Entity.  Castelle  has not agreed and is not  obligated to
     make any  future  investment  in or  capital  contribution  to any  Entity.
     Castelle  has not  guaranteed  and is not  responsible  or  liable  for any
     obligation  of any of the Entities in which it owns or has owned any equity
     interest.

     3.2 SEC Filings; Financial Statements.

     (a) Castelle has delivered to Ibex accurate and complete copies  (excluding
     copies of exhibits) of each report, registration statement (on a form other
     than Form S-8) and definitive  proxy  statement  filed by Castelle with the
     SEC between November 16, 1995 and the date of this Agreement (the "Castelle
     SEC  Documents").  As of the time it was filed with the SEC (or, if amended
     or superseded by a filing prior to the date of this Agreement,  then on the
     date of such filing):  (i) each of the Castelle SEC  Documents  complied in
     all material  respects with the applicable  requirements  of the Securities
     Act or the Exchange Act (as the case may be); and (ii) none of the Castelle
     SEC Documents  contained any untrue statement of a material fact or omitted
     to state a material  fact  required to be stated  therein or  necessary  in
     order to make the  statements  therein,  in the light of the  circumstances
     under which they were made, not misleading.

                                       34


     (b) The  consolidated  financial  statements  contained in the Castelle SEC
     Documents:  (i)  complied  as to form in all  material  respects  with  the
     published  rules and regulations of the SEC applicable  thereto;  (ii) were
     prepared  in  accordance  with  generally  accepted  accounting  principles
     applied on a consistent basis throughout the periods covered, except as may
     be indicated in the notes to such financial  statements and (in the case of
     unaudited  statements)  as  permitted by Form 10-QSB of the SEC, and except
     that  unaudited  financial  statements  may not contain  footnotes  and are
     subject  to  year-end  audit  adjustments;  and (iii)  fairly  present  the
     consolidated  financial position of Castelle and its subsidiaries as of the
     respective  dates  thereof and the  consolidated  results of  operations of
     Castelle and its subsidiaries for the periods covered thereby.

     3.3 Capitalization, Etc.

     (a) The authorized  capital stock of Castelle  consists of: (i) twenty-five
     million  (25,000,000)  shares of Common Stock (with no par value), of which
     three  million  six  hundred  twenty  thousand  eight  hundred   forty-four
     (3,620,844)  shares  have been issued and are  outstanding  as of August 7,
     1996; and (ii) two million  (2,000,000)  shares of Preferred Stock (with no
     par  value),  none of which such  shares have been issued as of the date of
     this Agreement. All of the outstanding shares of Castelle Common Stock have
     been  duly  authorized  and  validly   issued,   and  are  fully  paid  and
     non-assessable.

     (b) Castelle has reserved  nine hundred  forty-five  thousand  five hundred
     eighty-three  (945,583)  shares of Castelle Common Stock for issuance under
     its 1988  Incentive  Stock Plan, of which options to purchase three hundred
     sixty thousand four hundred twelve  (360,412)  shares are outstanding as of
     August 13, 1996. In addition,  the Company has reserved one hundred  twenty
     thousand  (120,000)  shares of Common  Stock  for  issuance  under the 1995
     Outside  Directors'  Stock  Option Plan,  of which  options to purchase ten
     thousand  (10,000) shares are outstanding as of the date of this Agreement.
     The Company also has  outstanding  warrants for the purchase of two hundred
     forty-eight  thousand  three  hundred  thirty-two  (248,332)  shares of the
     Company's  Common  Stock.  Except as set forth in Part 3.3 of the  Castelle
     Disclosure  Schedule,  there is no: (i) outstanding  subscription,  option,
     call,  warrant or right (whether or not currently  exercisable)  to acquire
     any shares of the  capital  stock or other  securities  of  Castelle;  (ii)
     outstanding  security,  instrument  or  obligation  that  is or may  become
     convertible  into or  exchangeable  for any shares of the capital  stock or
     other securities of Castelle; (iii) Contract under which Castelle is or may
     become obligated to sell or otherwise issue any shares of its capital stock
     or any other securities;  or (iv) to the best of the knowledge of Castelle,
     condition or circumstance  that may give rise to or provide a basis for the
     assertion  of a claim by any  Person  to the  effect  that  such  Person is
     entitled  to  acquire  or  receive  any  shares of  capital  stock or other
     securities of Castelle.

     (c) All outstanding  shares of Castelle  Common Stock,  and all outstanding
     Castelle  Options,  have been issued and granted in compliance with (i) all
     applicable  securities laws and other  applicable Legal  Requirements,  and
     (ii) all requirements set forth in applicable Contracts.

                                       35


     3.4 Authority;  Binding Nature of Agreement.  Castelle has the absolute and
unrestricted  right, power and authority to perform their obligations under this
Agreement;  and the  execution,  delivery  and  performance  by Castelle of this
Agreement  (including the contemplated  issuance of Castelle Common Stock in the
Merger in  accordance  with this  Agreement)  have been duly  authorized  by all
necessary action on the part of Castelle and its respective boards of directors.
This Agreement  constitutes the legal, valid and binding obligation of Castelle,
enforceable  against it in  accordance  with its  terms,  subject to (i) laws of
general  application  relating  to  bankruptcy,  insolvency  and the  relief  of
debtors, and (ii) rules of law governing specific performance, injunctive relief
and other  equitable  remedies.  

     3.5  Absence of  Changes.  Except as set forth in Part 3.5 of the  Castelle
Disclosure Schedule, since June 28, 1996:

     (a) there has not been any material adverse change in Castelle's  business,
     condition,  assets,  liabilities,   operations,  financial  performance  or
     prospects,  and, to the best of the  knowledge  of  Castelle,  no event has
     occurred  that will,  or could  reasonably  be expected to, have a Material
     Adverse Effect on Castelle;

     (b) there has not been any material loss,  damage or destruction to, or any
     material  interruption in the use of, any of Castelle's  assets (whether or
     not covered by insurance);

     (c) Castelle has not declared,  accrued,  set aside or paid any dividend or
     made any other  distribution in respect of any shares of capital stock, and
     has not repurchased, redeemed or otherwise reacquired any shares of capital
     stock or other securities;

     (d) Castelle  has not sold,  issued or  authorized  the issuance of (i) any
     capital stock or other  security  (except for Castelle  Common Stock issued
     upon the  exercise of  outstanding  Castelle  Options),  (ii) any option or
     right to  acquire  any  capital  stock or any other  security  (except  for
     Castelle Options identified in Section 3.3 of the Agreement),  or (iii) any
     instrument  convertible into or exchangeable for any capital stock or other
     security;

     (e)  Castelle  has not  amended  or  waived  any of its  rights  under,  or
     permitted the  acceleration of vesting under, (i) any provision of its 1988
     Incentive Stock Plan or 1995 Outside Directors' Stock Option Plan, (ii) any
     provision of any agreement  evidencing any outstanding  Castelle Option, or
     (iii) any restricted stock purchase agreement;

     (f) there has been no amendment to Castelle's  articles of incorporation or
     bylaws,  and Castelle  has not effected or been a party to any  Acquisition
     Transaction,  recapitalization,  reclassification  of shares,  stock split,
     reverse stock split or similar transaction;

     (g) Castelle has not formed any subsidiary or acquired any equity  interest
     or other interest in any other Entity;

                                       36


     (h) Castelle has not made any capital  expenditure which, when added to all
     other capital  expenditures made on behalf of Castelle since June 30, 1996,
     exceeds $50,000;

     (i) Castelle has not (i) entered into or permitted  any of the assets owned
     or used by it to become bound by any Contract that is or would constitute a
     Material  Contract  (as  defined in Section  2.10(a)),  or (ii)  amended or
     prematurely  terminated,  or waived any material right or remedy under, any
     such Contract;

     (j)  Castelle has not (i)  acquired,  leased or licensed any right or other
     asset from any other Person,  (ii) sold or otherwise disposed of, or leased
     or licensed,  any right or other asset to any other Person, or (iii) waived
     or relinquished any right, except for immaterial rights or other immaterial
     assets acquired,  leased, licensed or disposed of in the ordinary course of
     business and consistent with Castelle's past practices;

     (k)  Castelle  has not written off as  uncollectible,  or  established  any
     extraordinary  reserve  with  respect to, any account  receivable  or other
     indebtedness;

     (l)  Castelle  has not made any  pledge of any of its  assets or  otherwise
     permitted any of its assets to become  subject to any  Encumbrance,  except
     for pledges of  immaterial  assets made in the ordinary  course of business
     and consistent with Castelle's past practices;

     (m) Castelle has not (i) lent money to any Person  (other than  pursuant to
     routine  travel  advances  made to  employees  in the  ordinary  course  of
     business),  or (ii) incurred or guaranteed  any  indebtedness  for borrowed
     money;

     (n) Castelle has not (i) established or adopted any Employee  Benefit Plan,
     (ii) paid any bonus or made any  profit-sharing  or similar  payment to, or
     increased the amount of the wages, salary, commissions,  fringe benefits or
     other  compensation  or  remuneration  payable  to,  any of its  directors,
     officers or employees, or (iii) hired any new employee;

     (o) Castelle has not changed any of its methods of accounting or accounting
     practices in any respect;

     (p) Castelle has not made any Tax election;

     (q) Castelle has not commenced or settled any Legal Proceeding;

     (r) Castelle has not entered  into any  material  transaction  or taken any
     other  material   action  outside  the  ordinary   course  of  business  or
     inconsistent with its past practices; and

     (s)  Castelle  has not  agreed  or  committed  to take  any of the  actions
     referred to in clauses "(c)" through "(r)" above.

                                       37


     3.6 Title to Assets.  Castelle  owns,  and has good,  valid and  marketable
title to,  all assets  purported  to be owned by it,  including:  (i) all assets
reflected in the financial  statements  included in the Castelle SEC  Documents;
(ii) all assets  referred to in Sections 3.1 and 3.7 of the Castelle  Disclosure
Schedule;  and (iii) all other assets  reflected in Castelle's books and records
as being  owned by  Castelle.  Except as set  forth in Part 3.6 of the  Castelle
Disclosure Schedule,  all of said assets are owned by Castelle free and clear of
any liens or other  Encumbrances,  except for (x) any lien for current taxes not
yet due and payable, and (y) minor liens that have arisen in the ordinary course
of business and that do not (in any case or in the aggregate) materially detract
from the value of the assets subject thereto or materially impair the operations
of Castelle.

     3.7 Proprietary Assets.

     (a) Except as set forth in Part 3.7(a) of the Castelle Disclosure Schedule,
     Castelle  has  good,   valid  and  marketable  title  to  all  of  Castelle
     Proprietary Assets, free and clear of all liens and other Encumbrances, and
     has a valid right to use all such Proprietary  Assets.  Except as set forth
     in  Part  3.7(a)  of the  Castelle  Disclosure  Schedule,  Castelle  is not
     obligated  to make any  payment to any  Person for the use of any  Castelle
     Proprietary  Asset.  Except  as set forth in Part  3.7(a)  of the  Castelle
     Disclosure  Schedule,  Castelle  has not  developed  jointly with any other
     Person any  Castelle  Proprietary  Asset  with  respect to which such other
     Person has any rights.

     (b) Castelle has taken all reasonable measures and precautions necessary to
     protect  and  maintain  the  confidentiality  and  secrecy of all  Castelle
     Proprietary Assets (except Castelle Proprietary Assets whose value would be
     unimpaired by public  disclosure) and otherwise to maintain and protect the
     value of all  Castelle  Proprietary  Assets.  Except  as set  forth in Part
     3.7(b) of the Castelle Disclosure Schedule, to the best of the knowledge of
     Castelle  after  due  inquiry  of its  officers,  directors  and  advisors,
     Castelle has not (other than pursuant to license  agreements)  disclosed or
     delivered to any Person,  or permitted  the  disclosure  or delivery to any
     Person  of,  (i) the source  code,  or any  portion or aspect of the source
     code, of any Castelle  Proprietary  Asset,  or (ii) the object code, or any
     portion or aspect of the object code, of any Castelle Proprietary Asset.

     (c) To the best of the  knowledge  of  Castelle  after due  inquiry  of its
     officers,  directors and advisors,  none of the Castelle Proprietary Assets
     infringes  or  conflicts  with any  Proprietary  Asset owned or used by any
     other Person. To the best of the knowledge of Castelle after due inquiry of
     its  officers,   directors  and  advisors,   Castelle  is  not  infringing,
     misappropriating or making any unlawful use of, and Castelle has not at any
     time  infringed,  misappropriated  or made any unlawful use of, or received
     any notice or other  communication (in writing or otherwise) of any actual,
     alleged,  possible or potential infringement,  misappropriation or unlawful
     use of, any  Proprietary  Asset owned or used by any other  Person.  To the
     best  of  the  knowledge  of  Castelle,  no  other  Person  is  infringing,
     misappropriating  or making any unlawful use of, and no  Proprietary  Asset
     owned or used by any other Person infringes or conflicts with, any Castelle
     Proprietary Asset.

                                       38


     (d) Except as set forth in Part 3.7(d) of the Castelle Disclosure Schedule:
     (i) each Castelle  Proprietary Asset conforms in all material respects with
     any specification,  documentation,  performance standard, representation or
     statement  made  or  provided  with  respect  thereto  by or on  behalf  of
     Castelle;  and (ii) there has not been any claim by any  customer  or other
     Person alleging that any Castelle Proprietary Asset (including each version
     thereof that has ever been licensed or otherwise made available by Castelle
     to  any  Person)  does  not  conform  in all  material  respects  with  any
     specification,   documentation,  performance  standard,  representation  or
     statement made or provided by or on behalf of Castelle, and, to the best of
     the knowledge of Castelle,  there is no basis for any such claim.  Castelle
     has established adequate reserves on its consolidated  financial statements
     contained in the Castelle SEC Documents to cover all costs  associated with
     any  obligations  that Castelle may have with respect to the  correction or
     repair of  programming  errors or other  defects  in  Castelle  Proprietary
     Assets.

     (e) Castelle  Proprietary  Assets  constitute  all the  Proprietary  Assets
     necessary to enable Castelle to conduct its business in the manner in which
     such business has been and is being conducted.  Except as set forth in Part
     3.7(e) of the Castelle Disclosure  Schedule,  (i) Castelle has not licensed
     any of Castelle Proprietary Assets to any Person on an exclusive basis, and
     (ii)  Castelle has not entered into any covenant not to compete or Contract
     limiting its ability to exploit fully any of its  Proprietary  Assets or to
     transact business in any market or geographical area or with any Person.

     (f) Except as set forth in Part 3.7(f) of the Castelle Disclosure Schedule,
     (i) all  current  and  former  employees  of  Castelle  have  executed  and
     delivered  to  Castelle  an  agreement  (containing  no  exceptions  to  or
     exclusions from the scope of its coverage) that is substantially  identical
     to the form of Castelle Employee  Agreement  Concerning  Inventions,  Trade
     Secrets and Confidential Information previously delivered to Ibex, and (ii)
     all current and former consultants and independent  contractors to Castelle
     have  executed  and  delivered  to Castelle  an  agreement  (containing  no
     exceptions  to or  exclusions  from  the  scope  of its  coverage)  that is
     substantially identical to the form of Consultant Confidential  Information
     and Invention Assignment Agreements previously delivered to Ibex.

     3.8 Liabilities.  Castelle has no accrued,  contingent or other liabilities
of any  nature,  either  matured or  unmatured  (whether  or not  required to be
reflected  in  financial   statements  in  accordance  with  generally  accepted
accounting  principles,  and whether  due or to become  due),  except  for:  (a)
liabilities  identified as such in the "liabilities"  column of the consolidated
financial  statements  contained  in the Castelle  SEC  Documents;  (b) accounts
payable or accrued  salaries that have been incurred by Castelle  since June 30,
1996 in the ordinary  course of business and  consistent  with  Castelle's  past
practices;  and (c) the  liabilities  identified  in  Part  3.8 of the  Castelle
Disclosure Schedule.

     3.9  Compliance  with  Legal  Requirements.   To  the  best  of  Castelle's
knowledge,  Castelle is, and has at all times since  December 31, 1992 been,  in
compliance with all applicable Legal  Requirements,  except where the failure to
comply  with such  Legal  Requirements  has not had and will not have a Material
Adverse  Effect on  Castelle.  Except  as set forth in Part 3.9 of the  Castelle
Disclosure  Schedule,  since  December 31,  1992,  Castelle has not received any

                                       39


notice or other communication from any Governmental Body regarding any actual or
possible violation of, or failure to comply with, any Legal Requirement.

     3.10   Governmental   Authorizations.   Castelle  holds  all   Governmental
Authorizations  necessary  to enable  Castelle  to conduct  its  business in the
manner in which its business is currently being  conducted.  Castelle is, and at
all times since December 31, 1992 has been, in substantial  compliance  with the
material terms and  requirements of the respective  Governmental  Authorizations
necessary for its business.  Since December 31, 1992,  Castelle has not received
any notice or other  communication  from any Governmental Body regarding (a) any
actual  or  possible  violation  of or  failure  to  comply  with  any  term  or
requirement of any Governmental Authorization necessary for its business, or (b)
any  actual  or  possible  revocation,  withdrawal,  suspension,   cancellation,
termination or modification of any Governmental  Authorization necessary for its
business.

     3.11 Tax Matters.

     (a) All Tax Returns  required to be filed by or on behalf of Castelle  with
     any  Governmental  Body with  respect to any  taxable  period  ending on or
     before the Closing Date (the  "Castelle  Returns") (i) have been or will be
     filed on or before the  applicable  due date  (including  any extensions of
     such due date),  and (ii) have been, or will be when filed,  accurately and
     completely  prepared  in all  material  respects  in  compliance  with  all
     applicable Legal Requirements.  All amounts shown on Castelle Returns to be
     due on or before  the  Closing  Date have been or will be paid on or before
     the Closing Date.

     (b) Castelle  Financial  Statements  fully accrue all actual and contingent
     liabilities for Taxes with respect to all periods through the dates thereof
     in accordance with generally accepted accounting principles.  Castelle will
     establish,  in the ordinary course of business and consistent with its past
     practices,  reserves  adequate  for the payment of all Taxes for the period
     from June 30, 1996 through the Closing Date.

     (c) No Castelle  Return  relating to income Taxes has ever been examined or
     audited by any Governmental  Body.  Except as set forth in Part 3.11 of the
     Castelle Disclosure Schedule,  there have been no examinations or audits of
     any Castelle Return.

     (d) Except as set forth in Part 3.11 of the Castelle  Disclosure  Schedule,
     no claim or  Proceeding is pending or has been  threatened  against or with
     respect  to  Castelle  in  respect  of any Tax.  There  are no  unsatisfied
     liabilities for Taxes (including liabilities for interest, additions to tax
     and penalties  thereon and related  expenses) with respect to any notice of
     deficiency or similar document received by Castelle with respect to any Tax
     (other  than  liabilities  for  Taxes  asserted  under  any such  notice of
     deficiency or similar  document which are being  contested in good faith by
     Castelle and with respect to which adequate  reserves for payment have been
     established).  There  are no liens  for  Taxes  upon any of the  assets  of
     Castelle  except liens for current Taxes not yet due and payable.  Castelle
     has not entered into or become bound by any  agreement or consent  pursuant
     to Section 341(f) of the Code. Castelle has not been, and Castelle will not

                                       40


     be, required to include any adjustment in taxable income for any tax period
     (or  portion  thereof)  pursuant  to Section 481 or 263A of the Code or any
     comparable  provision  under  state or  foreign  Tax  laws as a  result  of
     transactions or events occurring, or accounting methods employed,  prior to
     the Closing.

     (e) There is no agreement, plan, arrangement or other Contract covering any
     employee  or  independent  contractor  or former  employee  or  independent
     contractor  of  Castelle  that,   considered   individually  or  considered
     collectively  with any other such Contracts,  will, or could  reasonably be
     expected to, give rise  directly or indirectly to the payment of any amount
     that would not be deductible pursuant to Section 280G or Section 162 of the
     Code.  Castelle is not,  and has never been, a party to or bound by any tax
     indemnity  agreement,  tax sharing agreement,  tax allocation  agreement or
     similar Contract.

     3.12 Employee and Labor Matters;  Benefit Plans.  Each of Castelle's  Plans
has been operated and  administered in all material  respects in accordance with
applicable Legal Requirements, including but not limited to ERISA and the Code.

     3.13  Environmental  Matters.  Castelle is in  compliance  in all  material
respects with all applicable  Environmental  Laws, which compliance includes the
possession  by Castelle of all  permits  and other  Governmental  Authorizations
required under applicable  Environmental Laws, and compliance with the terms and
conditions thereof.  Castelle has not received any notice or other communication
(in writing or otherwise),  whether from a Governmental  Body,  citizens  group,
employee or otherwise,  that alleges that Castelle is not in compliance with any
Environmental  Law, and, to the best of the knowledge of Castelle,  there are no
circumstances that may prevent or interfere with Castelle's  compliance with any
Environmental  Law in the future.  To the best of the knowledge of Castelle,  no
current or prior owner of any  property  leased or  controlled  by Castelle  has
received any notice or other  communication  (in writing or otherwise),  whether
from a Government Body, citizens group, employee or otherwise, that alleges that
such  current  or  prior  owner  or  Castelle  is not  in  compliance  with  any
Environmental Law. (For purposes of this Section 3.13: (i)  "Environmental  Law"
means any  federal,  state,  local or  foreign  Legal  Requirement  relating  to
pollution or protection of human health or the  environment  (including  ambient
air, surface water, ground water, land surface or subsurface strata),  including
any law or regulation relating to emissions,  discharges, releases or threatened
releases of Materials of  Environmental  Concern,  or otherwise  relating to the
manufacture,   processing,  distribution,  use,  treatment,  storage,  disposal,
transport or handling of Materials of Environmental Concern; and (ii) "Materials
of Environmental Concern" include chemicals, pollutants,  contaminants,  wastes,
toxic substances,  petroleum and petroleum products and any other substance that
is now  regulated  by any  Environmental  Law or that is  otherwise  a danger to
health, reproduction or the environment.)

     3.14 Legal Proceedings; Orders.

     (a) Except as set forth in Part 3.14 of the Castelle  Disclosure  Schedule,
     there is no pending Legal Proceeding,  and (to the best of the knowledge of
     Castelle) no Person has  threatened to commence any Legal  Proceeding:  (i)
     that  involves  Castelle or any of the assets  owned or used by Castelle or

                                       41


     any Person whose  liability  Castelle has or may have  retained or assumed,
     either  contractually or by operation of law; or (ii) that  challenges,  or
     that may  have the  effect  of  preventing,  delaying,  making  illegal  or
     otherwise  interfering  with,  the Merger or any of the other  transactions
     contemplated by this  Agreement.  To the best of the knowledge of Castelle,
     except as set forth in Part 3.14 of the Castelle  Disclosure  Schedule,  no
     event  has  occurred,   and  no  claim,   dispute  or  other  condition  or
     circumstance  exists,  that will, or that could  reasonably be expected to,
     give rise to or serve as a basis  for the  commencement  of any such  Legal
     Proceeding.

     (b)  There is no  order,  writ,  injunction,  judgment  or  decree to which
     Castelle,  or any of the assets owned or used by Castelle,  is subject.  To
     the best of the  knowledge  of  Castelle,  no officer or other  employee of
     Castelle is subject to any order, writ, injunction, judgment or decree that
     prohibits such officer or other employee from engaging in or continuing any
     conduct, activity or practice relating to Castelle's business.

     3.15 Non-Contravention;  Consents.  Except as set forth in Part 3.15 of the
Castelle Disclosure Schedule, neither (1) the execution, delivery or performance
of this Agreement or any of the other agreements  referred to in this Agreement,
nor  (2)  the  consummation  of the  Merger  or any  of the  other  transactions
contemplated  by this  Agreement,  will directly or indirectly  (with or without
notice or lapse of time):

     (a)  contravene,  conflict  with or result in a violation of (i) any of the
     provisions of Castelle's  articles of incorporation or bylaws,  or (ii) any
     resolution  adopted  by  Castelle's   shareholders,   Castelle's  board  of
     directors or any committee of Castelle's board of directors;

     (b)  contravene,  conflict  with or result in a  violation  of, or give any
     Governmental  Body or  other  Person  the  right  to  challenge  any of the
     transactions  contemplated  by this  Agreement or to exercise any remedy or
     obtain  any  relief  under,  any  Legal  Requirement  or any  order,  writ,
     injunction,  judgment  or decree to which  Castelle,  or any of the  assets
     owned or used by Castelle, is subject;

     (c) contravene,  conflict with or result in a violation of any of the terms
     or  requirements  of, or give any  Governmental  Body the right to  revoke,
     withdraw,   suspend,   cancel,   terminate  or  modify,   any  Governmental
     Authorization  that is held  by  Castelle  or  that  otherwise  relates  to
     Castelle's business or to any of the assets owned or used by Castelle;

     (d)  contravene,  conflict  with or result in a violation  or breach of, or
     result in a material default under, any provision of any Castelle  Contract
     that is or would  constitute  a Material  Contract,  or give any Person the
     right to (i)  declare a  default  or  exercise  any  remedy  under any such
     Castelle Contract,  (ii) accelerate the maturity or performance of any such
     Castelle Contract,  or (iii) cancel,  terminate or modify any such Castelle
     Contract; or

     (e) result in the  imposition or creation of any lien or other  Encumbrance
     upon or with  respect to any asset  owned or used by  Castelle  (except for
     minor  liens  that will not,  in any case or in the  aggregate,  materially
     detract from the value of the assets subject  thereto or materially  impair
     the operations of Castelle).

                                       42


Except as set forth in Part 3.15 of the Castelle  Disclosure  Schedule or as may
be required by the Exchange Act,  Securities  Act, state  securities or blue sky
laws,  the CGCL and the NASD  Bylaws  (as they  relate  to the S-4  Registration
Statement and the  Prospectus/Proxy  Statement,  or the Information  Statement),
Castelle  is not and will not be  required  to make any filing  with or give any
notice to, or to obtain any Consent from, any Person in connection  with (x) the
execution,  delivery  or  performance  of  this  Agreement  or any of the  other
agreements referred to in this Agreement,  or (y) the consummation of the Merger
or any of the other transactions contemplated by this Agreement.

     3.16 Full Disclosure.

     (a) This Agreement  (including the Castelle  Disclosure  Schedule) does not
     (i) contain any  representation,  warranty or information  that is false or
     misleading  with  respect to any material  fact,  or (ii) omit to state any
     material fact  necessary in order to make the  representations,  warranties
     and  information  contained and to be contained  herein and therein (in the
     light of the circumstances under which such representations, warranties and
     information were or will be made or provided) not false or misleading.

     (b) Should Castelle elect to file a permit  application under Section 25121
     of the California Corporations Code, including an Information Statement (as
     defined in Section 5.2), the information supplied by Castelle for inclusion
     in the  Information  Statement  (as defined in Section 5.2) will not, as of
     the  date  of  the  Information  Statement  or  as  of  the  date  of  Ibex
     Shareholders'  Meeting  (as  defined  in  Section  5.3),  (i)  contain  any
     statement  that is inaccurate  or  misleading  with respect to any material
     fact,  or (ii) omit to state any material  fact  necessary in order to make
     such  information  (in the  light of the  circumstances  under  which it is
     provided) not false or misleading.

     (c)  Should  Castelle  elect  to  prepare  and  file  an  S-4  Registration
     Statement,  none of the information  supplied or to be supplied by Castelle
     for  inclusion  or  incorporation  by  reference  in the  S-4  Registration
     Statement  will, at the time the S-4  Registration  Statement is filed with
     the SEC or at the time the S-4  Registration  Statement  becomes  effective
     under the Securities Act,  contain any untrue  statement of a material fact
     or omit to state  any  material  fact  required  to be  stated  therein  or
     necessary  in  order  to make  the  statements  therein,  in  light  of the
     circumstances  under  which  they are  made,  not  misleading.  None of the
     information  supplied  or to be  supplied  by  Castelle  for  inclusion  or
     incorporation by reference in the  Prospectus/Proxy  Statement will, at the
     dates  mailed to the  shareholders  of  Castelle  and  Ibex,  and as of the
     Effective Time,  contain any untrue statement of a material fact or omit to
     state any material fact required to be stated therein or necessary in order
     to make the statements  therein,  in light of the circumstances under which
     they are made, not misleading.

     3.17 Valid Issuance.  Subject to Section 1.5(b),  the Castelle Common Stock
to be issued in the Merger will,  when issued in accordance  with the provisions
of this Agreement, be validly issued, fully paid and nonassessable.

                                       43


SECTION 4. CERTAIN COVENANTS OF IBEX AND THE DESIGNATED SHAREHOLDERS

     4.1 Access  and  Investigation.  During  the  period  from the date of this
Agreement through the Effective Time (the "Pre-Closing Period"), Ibex shall, and
shall  cause  its  Representatives  to:  (a)  provide  Castelle  and  Castelle's
Representatives with reasonable access to Ibex's Representatives,  personnel and
assets and to all existing books,  records,  Tax Returns,  work papers and other
documents  and  information  relating  to Ibex;  and (b)  provide  Castelle  and
Castelle's  Representatives  with copies of such existing  books,  records,  Tax
Returns,  work papers and other documents and information  relating to Ibex, and
with  such  additional  financial,  operating  and  other  data and  information
regarding Ibex, as Castelle may reasonably request.

     4.2 Operation of Ibex's Business. During the Pre-Closing Period:

     (a) Ibex shall conduct its business and  operations in the ordinary  course
     and in  substantially  the same manner as such business and operations have
     been conducted prior to the date of this Agreement;

     (b) Ibex shall use  reasonable  efforts  to  preserve  intact  its  current
     business organization,  keep available the services of its current officers
     and employees and maintain its relations and good will with all  suppliers,
     customers,   landlords,  creditors,  employees  and  other  Persons  having
     business relationships with Ibex;

     (c) Ibex shall keep in full force all insurance policies identified in Part
     2.17 of the Disclosure Schedule;

     (d) Ibex shall cause its officers to report regularly (but in no event less
     frequently  than  weekly)  to  Castelle  concerning  the  status  of Ibex's
     business;

     (e) Ibex shall not declare,  accrue,  set aside or pay any dividend or make
     any other distribution in respect of any shares of capital stock, and shall
     not repurchase,  redeem or otherwise  reacquire any shares of capital stock
     or other securities (except that Ibex may repurchase Ibex Common Stock from
     former  employees  pursuant  to the  terms  of  existing  restricted  stock
     purchase agreements);

     (f) Ibex shall not sell, issue or authorize the issuance of (i) any capital
     stock or other  security,  (ii) any option or right to acquire  any capital
     stock or  other  security,  or (iii)  any  instrument  convertible  into or
     exchangeable  for any capital  stock or other  security  (except  that Ibex
     shall be  permitted,  (x) to issue Ibex Common Stock to employees  upon the
     exercise  of  outstanding  Ibex  Options,  and (y) to issue  shares of Ibex
     Common Stock upon the conversion of shares of Series A Preferred Stock);

     (g) Ibex  shall not amend or waive any of its rights  under,  or permit the
     acceleration  of vesting under,  (i) any provision of its 1992 Stock Option
     Plan, (ii) any provision of any agreement  evidencing any outstanding  Ibex
     Option, or (iii) any provision of any restricted stock purchase agreement;

                                       44


     (h)  neither  Ibex nor any of the  Designated  Shareholders  shall amend or
     permit the adoption of any amendment to Ibex's articles of incorporation or
     bylaws,  or  effect or  permit  Ibex to  become a party to any  Acquisition
     Transaction,  recapitalization,  reclassification  of shares,  stock split,
     reverse  stock  split or similar  transaction  (except  that Ibex may issue
     shares  of Ibex  Common  Stock  upon the  conversion  of shares of Series A
     Preferred Stock);

     (i) Ibex shall not form any  subsidiary  or acquire any equity  interest or
     other interest in any other Entity;

     (j) Ibex  shall  not make  any  capital  expenditure,  except  for  capital
     expenditures  that,  when added to all other capital  expenditures  made on
     behalf of Ibex  during the  Pre-Closing  Period,  do not exceed  $5,000 per
     month;

     (k) Ibex shall not (i) enter  into,  or permit  any of the assets  owned or
     used by it to become bound by, any Contract  that is or would  constitute a
     Material  Contract,  or (ii) amend or prematurely  terminate,  or waive any
     material right or remedy under, any such Contract;

     (l) Ibex shall not (i)  acquire,  lease or license any right or other asset
     from any other  Person,  (ii)  sell or  otherwise  dispose  of, or lease or
     license,  any right or other asset to any other  Person,  or (iii) waive or
     relinquish  any right,  except for assets  acquired,  leased,  licensed  or
     disposed of by Ibex pursuant to Contracts that are not Material Contracts;

     (m) Ibex shall not (i) lend money to any Person  (except that Ibex may make
     routine travel advances to employees in the ordinary course of business and
     may,  consistent with its past  practices,  allow employees to acquire Ibex
     Common  Stock in  exchange  for  promissory  notes  upon  exercise  of Ibex
     Options), or (ii) incur or guarantee any indebtedness for borrowed money;

     (n) Ibex shall not (i) establish, adopt or amend any Employee Benefit Plan,
     (ii) pay any  bonus  or make any  profit-sharing  payment,  cash  incentive
     payment or similar payment to, or increase the amount of the wages, salary,
     commissions,  fringe benefits or other compensation or remuneration payable
     to, any of its  directors,  officers  or  employees,  or (iii) hire any new
     employee;

     (o) Ibex shall not change any of its methods of  accounting  or  accounting
     practices in any material respect;

     (p) Ibex shall not make any Tax election;

     (q) Ibex shall not commence or settle any material Legal Proceeding;

     (r) Ibex shall not agree or commit to take any of the actions  described in
     clauses "(e)" through "(q)" above.

                                       45


Notwithstanding  the  foregoing,  Ibex may take any action  described in clauses
"(e)"  through "(r)" above if Castelle  gives its prior  written  consent to the
taking of such action by Ibex,  which consent will not be unreasonably  withheld
(it being  understood that Castelle's  withholding of consent to any action will
not be deemed  unreasonable if Castelle determines in good faith that the taking
of such action would not be in the best interests of Castelle or would not be in
the best interests of Ibex).

     4.3 Notification; Updates to Disclosure Schedule.

     (a) During the Pre-Closing  Period,  Ibex shall promptly notify Castelle in
     writing of:

          (i)  the  discovery  by  Ibex  of  any  event,   condition,   fact  or
          circumstance  that occurred or existed on or prior to the date of this
          Agreement and that caused or  constitutes a material  inaccuracy in or
          breach of any  representation  or warranty  made by Ibex or any of the
          Designated Shareholders in this Agreement;

          (ii) any event, condition, fact or circumstance that occurs, arises or
          exists  after  the  date of this  Agreement  and that  would  cause or
          constitute a material inaccuracy in or breach of any representation or
          warranty made by Ibex or any of the  Designated  Shareholders  in this
          Agreement if (A) such  representation  or warranty had been made as of
          the time of the  occurrence,  existence  or  discovery  of such event,
          condition, fact or circumstance, or (B) such event, condition, fact or
          circumstance  had occurred,  arisen or existed on or prior to the date
          of this Agreement;

          (iii) any breach of any covenant or  obligation  of Ibex or any of the
          Designated Shareholders; and

          (iv) any event,  condition,  fact or circumstance  that would make the
          timely satisfaction of any of the conditions set forth in Section 6 or
          Section 7 impossible or unlikely.

     (b) If any event,  condition,  fact or circumstance  that is required to be
     disclosed  pursuant to Section 4.3(a) requires any change in the Disclosure
     Schedule,  or if any such  event,  condition,  fact or  circumstance  would
     require such a change assuming the Disclosure Schedule were dated as of the
     date of the  occurrence,  existence or discovery of such event,  condition,
     fact or  circumstance,  then Ibex shall  promptly  deliver to  Castelle  an
     update to the Disclosure  Schedule  specifying such change.  No such update
     shall be deemed to  supplement  or amend the  Disclosure  Schedule  for the
     purpose of determining whether any of the conditions set forth in Section 6
     has been satisfied.

                                       46


SECTION 5. ADDITIONAL COVENANTS OF THE PARTIES

     5.1 Filings and Consents. As promptly as practicable after the execution of
this Agreement, each party to this Agreement (a) shall make all filings (if any)
and give all  notices  (if any)  required  to be made and given by such party in
connection  with the  Merger  and the other  transactions  contemplated  by this
Agreement,  and (b) shall use all commercially  reasonable efforts to obtain all
Consents  (if any)  required to be obtained  (pursuant to any  applicable  Legal
Requirement  or Contract,  or otherwise)  by such party in  connection  with the
Merger and the other  transactions  contemplated by this  Agreement.  Ibex shall
(upon  request)  promptly  deliver to Castelle a copy of each such filing  made,
each such  notice  given and each  such  Consent  obtained  by Ibex  during  the
Pre-Closing Period.

     5.2 California  Permit;  Fairness Hearing.  Promptly after the execution of
this  Agreement,  Ibex and Castelle shall prepare and cause to be filed with the
California Commissioner of Corporations (the "California Commissioner") a permit
application  under  Section 25121 of the  California  Corporations  Code,  and a
related  information  statement or other disclosure  document (the  "Information
Statement"),  and  shall  request  a hearing  on the  fairness  of the terms and
conditions  of  the  Merger   pursuant  to  Section  25142  of  the   California
Corporations  Code.  The parties to this  Agreement  shall use all  commercially
reasonable efforts to cause the California  Commissioner to approve the fairness
of the terms and conditions of the Merger at such a hearing; provided,  however,
that Castelle  shall not be required to modify any of the terms of the Merger in
order to cause the California Commissioner to approve the fairness of such terms
and conditions. Ibex shall provide and include in the Information Statement such
information  relating  to Ibex as may be  required  pursuant to the rules of the
California   Commissioner.   The   Information   Statement   shall  include  the
recommendation of the board of directors of Ibex in favor of the Merger.

     5.3 Ibex Shareholders' Meeting. Ibex shall, in accordance with its articles
of  incorporation  and bylaws and the applicable  requirements of the CGCL, call
and hold a special  meeting of its  shareholders  as promptly as practicable for
the  purpose of  permitting  them to  consider  and to vote upon and approve the
Merger  and  this  Agreement  (the  "Ibex  Shareholders'  Meeting").  As soon as
permissible  under  the  rules  of the  California  Commissioner  or the SEC (as
applicable),  Ibex  shall  cause  a copy  of the  Information  Statement  or the
Prospectus/Proxy  Statement (as applicable) to be delivered to each  shareholder
of Ibex who is entitled to vote at the Ibex Shareholders'  Meeting. Each Signing
Shareholder  shall cause all shares of the capital stock of Ibex that are owned,
beneficially  or of record,  by such Signing  Shareholder on the record date for
Ibex Shareholders' Meeting to be voted in favor of the Merger and this Agreement
at such meeting.

     5.4 Public  Announcements.  During the Pre-Closing Period, (a) neither Ibex
nor any of the Designated  Shareholders  shall (and Ibex shall not permit any of
its  Representatives  to) issue any press  release or make any public  statement
regarding  this  Agreement  or  the  Merger,  or  regarding  any  of  the  other
transactions  contemplated by this Agreement,  without  Castelle's prior written
consent, and (b) Castelle will use reasonable efforts to consult with Ibex prior
to  issuing  any press  release or making any  public  statement  regarding  the
Merger.

                                       47


     5.5 Pooling of Interests.  During the Pre-Closing  Period, no party to this
Agreement  shall take any action  that could  reasonably  be expected to have an
adverse  effect on the  ability  of  Castelle  to  account  for the  Merger as a
"pooling of interests."

     5.6  Affiliate  Agreements.  Each  Signing  Shareholder  shall  execute and
deliver to Castelle,  and Ibex shall use all commercially  reasonable efforts to
cause each other  Person  identified  on Exhibit C-2 (and any other  Person that
could  reasonably  be deemed to be an  "affiliate"  of Ibex for  purposes of the
Securities Act), to execute and deliver to Castelle,  as promptly as practicable
after the  execution of this  Agreement,  an Affiliate  Agreement in the form of
Exhibit C-1 and a Proxy in the form of Exhibit M.

     5.7  Best  Efforts.  During  the  Pre-Closing  Period,  (a)  Ibex  and  the
Designated Shareholders shall use their best efforts to cause the conditions set
forth in Section 6 to be satisfied on a timely basis, and (b) Castelle shall use
its best efforts to cause the  conditions set forth in Section 7 to be satisfied
on a timely basis.

     5.8 Tax Matters.  Prior to the Closing, (a) Castelle and Ibex shall execute
and deliver,  to Cooley Godward  Castro  Huddleson & Tatum and to Graham & James
LLP, tax  representation  letters in substantially  the form of Exhibit D (which
will be used in  connection  with the legal  opinions  contemplated  by Sections
6.6(j) and 7.3(b),  and (b)  shareholders of Ibex  receiving:  (i) fifty percent
(50%) or more of the Castelle Common Stock issued in the Merger, and (ii) shares
of Castelle Common Stock with a fair market value greater than or equal to fifty
percent (50%) of the aggregate cash payments due under the Employment Agreements
and the Noncompetition  Agreements executed by the persons identified on Exhibit
F (the  "Continuity  of  Interest  Shareholders")  shall  execute and deliver to
Cooley  Godward Castro  Huddleson & Tatum and Graham & James LLP,  Continuity of
Interest  Certificates in the form of Exhibit E with respect to such shares. For
purposes of this Section,  the fair market value of Castelle  Common Stock shall
be the  closing  price  on the  Nasdaq  National  System  on  the  business  day
immediately preceding the Closing Date.

     5.9 Employment and Noncompetition  Agreements.  At or prior to the Closing,
each of the  persons  identified  on  Exhibit F shall  execute  and  deliver  to
Castelle  an  Employment  Agreement  in the form of  Exhibit  G (an  "Employment
Agreement")  and (if indicated on Exhibit F) a  Noncompetition  Agreement in the
form of Exhibit H (a "Noncompetition Agreement").

     5.10 FIRPTA Matters.  At the Closing,  (a) Ibex shall deliver to Castelle a
statement (in such form as may be  reasonably  requested by counsel to Castelle)
conforming  to the  requirements  of Section  1.897 -  2(h)(1)(i)  of the United
States Treasure Regulations,  and (b) Ibex shall deliver to the Internal Revenue
Service the  notification  required  under Section  1.897-2(h)(2)  of the United
States Treasury Regulations.

     5.11 Acquisition  Proposals.  From the date hereof until the earlier of the
termination of this Agreement or the  consummation  of the Merger,  Castelle and
Ibex will not, and will cause their respective officers,  directors,  employees,
agents and representatives not to, directly or indirectly,  encourage,  solicit,

                                       48


accept,  initiate  or conduct  discussions  or  negotiations  with,  provide any
information to, or enter into any agreement with, any corporation,  partnership,
limited  liability  company,  person  or other  entity or group  concerning  the
acquisition  of all or a  substantial  part of the  assets,  business or capital
stock of Castelle or Ibex,  whether  through  purchase,  merger,  consolidation,
exchange  or  any  other  business  combination  (each  of  the  foregoing,   an
"Acquisition  Proposal").  Notwithstanding  anything  to  the  contrary  in  the
preceding  sentence,  nothing  herein  shall  prevent  Castelle  or Ibex and its
officers and directors,  from  responding to and  considering  unsolicited  firm
offers for any such transaction from other persons if and to the extent that, in
the written opinion of Castelle or Ibex outside counsel,  respectively,  failure
to do so would be reasonably  likely to constitute a violation of applicable law
or a  breach  of  the  fiduciary  duties  of  that  company's  directors  to its
shareholders. Each company shall immediately provide written notice to the other
company  of the terms and  other  details  of any such  unsolicited  inquiry  or
proposal relating to an Acquisition Proposal. In the event that Castelle or Ibex
or any of their  officers  or  directors  enters into any such  negotiations  or
discussions  for any reason  which  thereby  constitute a breach of this Section
5.11,  such  company  shall  immediately  reimburse  the other  company  for all
expenses and costs incurred by that company in connection with the  transactions
contemplated by this Agreement.  In the event that Castelle or Ibex any of their
officers or directors  shall enter into any letter of intent,  understanding  or
other  agreement  with another  party  relating to the  acquisition  of all or a
substantial  part of the assets,  business or capital stock of Castelle or Ibex,
as, applicable, whether through purchase, merger, consolidation, exchange or any
other  business  combination,  either in violation of the no-shop  agreement set
forth in this  Section  or within  nine (9)  months  after  termination  of this
Agreement  for any reason,  then  immediately  upon entering into such letter of
intent,  understanding or other agreement, such company shall pay to Castelle or
Ibex,  as  applicable,  a  termination  fee  in  the  amount  of  $250,000  (the
"Termination Fee");  provided,  however,  that such Termination Fee shall not be
payable  if,  prior to the entry by such  company  into such  letter of  intent,
understanding  or  other   agreement,   Castelle  or  Ibex,  as  applicable  has
unilaterally  declined to close the Merger.  The parties  acknowledge  and agree
that the expense reimbursement  obligation and Termination Fee described in this
Section shall not be the exclusive remedy to the injured party in the event of a
breach of this  Agreement,  and, in any such event,  the injured  party shall be
entitled,  in  addition to  receiving  such  payments,  to  equitable  remedies,
including, without limitation, specific performance and enjoining of any actions
determined to be in breach of this Agreement.

SECTION 6. CONDITIONS PRECEDENT TO OBLIGATIONS OF CASTELLE

     The  obligations of Castelle to effect the Merger and otherwise  consummate
the transactions contemplated by this Agreement are subject to the satisfaction,
at or prior to the Closing, of each of the following conditions:

     6.1 Satisfactory  Completion of Pre-Acquisition Review. Castelle shall have
satisfactorily  completed its pre-acquisition  investigation and review of Ibex'
business, condition, assets, liabilities, operations, financial performance, net
income  and  prospects  and  shall  be  satisfied   with  the  results  of  that
investigation and review.

                                       49


     6.2 Accuracy of Representations. Each of the representations and warranties
made by Ibex and the  Designated  Shareholders  in this Agreement and in each of
the other  agreements and  instruments  delivered to Castelle in connection with
the transactions  contemplated by this Agreement shall have been accurate in all
material respects as of the date of this Agreement, and shall be accurate in all
material  respects as of the Scheduled  Closing Time as if made at the Scheduled
Closing Time (without giving effect to any update to the Disclosure Schedule).

     6.3  Performance of Covenants.  All of the covenants and  obligations  that
Ibex and the Designated  Shareholders  are required to comply with or to perform
at or prior to the Closing  shall have been  complied  with and performed in all
respects.

     6.4 Shareholder Approval. The principal terms of the Merger shall have been
duly approved by the affirmative  vote of at least (a) 98% of the shares of Ibex
Common  Stock  entitled to vote with respect  thereto,  (b) all of the shares of
Series A Preferred Stock entitled to vote with respect  thereto,  and 51% of the
shares of Castelle Common Stock entitled to vote with respect thereto.

     6.5 Consents.  All Consents  required to be obtained in connection with the
Merger and the other transactions  contemplated by this Agreement (including the
Consents  identified in Part 2.21 of the  Disclosure  Schedule)  shall have been
obtained and shall be in full force and effect.

     6.6 Agreements  and  Documents.  Castelle shall have received the following
agreements and documents (referred to herein as the "Transactional  Documents"),
each of which shall be in full force and effect:

     (a) Affiliate Agreements in the form of Exhibit C-1 and Proxies in the form
     of Exhibit M, executed by the Persons  identified on Exhibit C-2 and by any
     other Person who could  reasonably be deemed to be an  "affiliate"  of Ibex
     for purposes of the Securities Act;

     (b)  Employment  Agreements  in the  form of  Exhibit  G,  executed  by the
     individuals identified on Exhibit F;

     (c)  Noncompetition  Agreements  in the form of Exhibit H,  executed by the
     individuals identified on Exhibit F;

     (d)   confidential   invention  and   assignment   agreements,   reasonably
     satisfactory  in form and  content to  Castelle,  executed  by all  current
     employees  of  Ibex  and  by  all  current   consultants   and  independent
     contractors to Ibex who have not already signed such agreements  (including
     the current employees,  consultants and independent  contractors identified
     in Part 2.9(f) of the Disclosure Schedule);

     (e) the statement referred to in Section 5.10(a), executed by Ibex;

                                       50


     (f) Continuity of Interest  Certificates in the form of Exhibit E, executed
     by the Continuity of Interest Shareholders;

     (g) an  estoppel  certificate,  dated as of a date not more  than five days
     prior to the Closing Date and satisfactory in form and content to Castelle,
     executed  by Cameron &  Associates,  629 J Street,  Sacramento,  California
     95812 and Shelter Bay Company, 655 Redwood Highway, Suite 177, Mill Valley,
     California 94941.

     (h) a legal opinion of Graham & James LLP, dated as of the Closing Date, in
     the form of Exhibit I;

     (i) a legal opinion of Cooley Godward Castro Huddleson & Tatum, dated as of
     the Closing Date, in the form of Exhibit J;

     (j) a legal opinion of Cooley Godward Castro Huddleson & Tatum, dated as of
     the Closing Date and reasonably  satisfactory  to Ibex and its counsel,  to
     the effect  that the Merger will  constitute  a  reorganization  within the
     meaning of Section 368 of the Code (it being  understood that, in rendering
     such  opinion,  such counsel may rely upon the tax  representation  letters
     referred to in Section 5.8(a) and the  Continuity of Interest  Certificates
     referred to in Section 5.8(b));

     (k) a letter from  Coopers & Lybrand  LLP,  dated as of the  Closing  Date,
     confirming  that (a)  Castelle  may account for the Merger as a "pooling of
     interests" in accordance  with generally  accepted  accounting  principles,
     Accounting  Principles  Board  Opinion  No.  16 and  all  published  rules,
     regulations and policies of the SEC, and (b) confirming that no transaction
     entered into by Ibex, and no other fact or  circumstance  relating to Ibex,
     will  prevent  Castelle  from  accounting  for the Merger as a "pooling  of
     interests" in accordance  with generally  accepted  principles,  Accounting
     Principles  Board Opinion No. 16 and all published  rules,  regulations and
     policies of the SEC; and

     (l) a certificate  executed by the Designated  Shareholders  and containing
     the representation and warranty of each Designated Shareholder that each of
     the  representations  and  warranties set forth in Section 2 is accurate in
     all respects as of the Closing Date as if made on the Closing Date and that
     the  conditions  set forth in Sections 6.2, 6.3, 6.4 and 6.5 have been duly
     satisfied (the "Designated Shareholders' Closing Certificate").

     6.7 FIRPTA  Compliance.  Ibex shall  have filed with the  Internal  Revenue
Service the notification referred to in Section 5.10(b).

     6.8 Securities Compliance. Either:

     (a) the  California  Commissioner  shall have issued a permit under Section
     25121 of the  California  Corporations  Code  (following a hearing upon the
     fairness of the terms and conditions of the Merger,  conducted  pursuant to

                                       51


     Section 25142 of the California  Corporations Code) for the issuance of the
     Castelle  Common  Stock to be  issued  in the  Merger,  and all  applicable
     requirements  of Section  3(a)(10)  of the  Securities  Act shall have been
     satisfied, or

     (b) a registration statement on Form S-4 covering the Castelle Common Stock
     to be issued in the Merger shall have been declared effective in accordance
     with the  provisions  of the  Securities  Act, and no stop order shall have
     been issued by the SEC with respect to the S-4 Registration Statement.

     6.9 No Restraints. No temporary restraining order, preliminary or permanent
injunction or other order  preventing the  consummation of the Merger shall have
been issued by any court of  competent  jurisdiction  and remain in effect,  and
there shall not be any Legal  Requirement  enacted or deemed  applicable  to the
Merger that makes consummation of the Merger illegal.

     6.10 Comfort  Letter.  Should  Castelle  elect to file an S-4  Registration
Statement,  Castelle  shall have  received a letter from  Coopers & Lybrand LLP,
dated  no  more  than  two  business  days  before  the  date on  which  the S-4
Registration Statement became effective (and reasonably satisfactory in form and
substance to  Castelle),  that is customary in scope and  substance  for letters
delivered by  independent  public  accountants in connection  with  registration
statements similar to the S-4 Registration Statement.

     6.11 No Legal Proceedings.  No Person shall have commenced or threatened to
commence any Legal Proceeding  challenging or seeking the recovery of a material
amount of damages in connection  with the Merger or seeking to prohibit or limit
the exercise by Castelle of any material right  pertaining to its acquisition of
Ibex.

     6.12  Amendment  of  Fourth  Amended  and  Restated   Registration   Rights
Agreement.  Amendment  of the Fourth  Amended and Restated  Registration  Rights
Agreement to include the  registration  rights granted the Signing  Shareholders
shall have been approved by Silicon Valley Bank and the holders of a majority of
the shares necessary to cause such amendment.

SECTION 7. CONDITIONS PRECEDENT TO OBLIGATIONS OF IBEX

     The  obligations of Ibex to effect the Merger and otherwise  consummate the
transactions contemplated by this Agreement are subject to the satisfaction,  at
or prior to the Closing, of the following conditions:

     7.1 Accuracy of Representations. Each of the representations and warranties
made by  Castelle in this  Agreement  shall have been  accurate in all  material
respects  as of the  date  of  this  Agreement  (without  giving  effect  to any
materiality  or similar  qualifications  contained in such  representations  and
warranties),  and shall be accurate in all material respects as of the Scheduled
Closing Time as if made at the Scheduled  Closing Time (without giving effect to
any materiality or similar qualifications  contained in such representations and
warranties).

                                       52


     7.2  Performance of Covenants.  All of the covenants and  obligations  that
Castelle  is  required  to comply  with or to perform at or prior to the Closing
shall have been complied with and performed in all respects.

     7.3 Documents. Ibex shall have received:

     (a) a legal opinion of Cooley Godward Castro Huddleson & Tatum, dated as of
     the Closing Date, in the form of Exhibit J;

     (b) a legal opinion of Graham & James LLC, dated as of the Closing Date and
     reasonably satisfactory to Castelle and its counsel, to the effect that the
     Merger will constitute a  reorganization  within the meaning of Section 368
     of the Code (it being  understood  that, in rendering  such  opinion,  such
     counsel may rely upon the tax representation letters referred to in Section
     5.8(a) and the Continuity of Interest  Certificates  referred to in Section
     5.8(b);

     (c) Continuity of Interest  Certificates in the form of Exhibit E, executed
     by the Continuity of Interest Shareholders.

     7.4 Shareholder Approval. The principal terms of the Merger shall have been
duly approved by the affirmative  vote of at least (a) 98% of the shares of Ibex
Common  Stock  entitled to vote with respect  thereto,  (b) all of the shares of
Series A Preferred Stock entitled to vote with respect  thereto,  and 51% of the
shares of Castelle Common Stock entitled to vote with respect thereto.

     7.5 No Restraints. No temporary restraining order, preliminary or permanent
injunction or other order  preventing the  consummation of the Merger shall have
been issued by any court of  competent  jurisdiction  and remain in effect,  and
there shall not be any Legal  Requirement  enacted or deemed  applicable  to the
Merger that makes consummation of the Merger illegal.

     7.6 Consents.  All Consents  required to be obtained in connection with the
Merger and the other transactions  contemplated by this Agreement (including the
Consents  identified in Part 3.15 of the  Disclosure  Schedule)  shall have been
obtained and shall be in full force and effect.

     7.7 Securities Compliance. Either:

     (a) the  California  Commissioner  shall have issued a permit under Section
     25121 of the  California  Corporations  Code  (following a hearing upon the
     fairness of the terms and conditions of the Merger,  conducted  pursuant to
     Section 25142 of the California  Corporations Code) for the issuance of the
     Castelle  Common  Stock to be  issued  in the  Merger,  and all  applicable
     requirements of Section 3(a)(10) of the Securities Act have been satisfied,
     or

                                       53


     (b) a registration statement on Form S-4 covering the Castelle Common Stock
     to be issued in the Merger shall have been declared effective in accordance
     with the  provisions  of the  Securities  Act, and no stop order shall have
     been issued by the SEC with respect to the S-4 Registration Statement.

     7.8 No Legal  Proceedings.  No Person shall have commenced or threatened to
commence any Legal Proceeding  challenging or seeking the recovery of a material
amount of damages in connection  with the Merger or seeking to prohibit or limit
the exercise by Castelle of any material right  pertaining to its acquisition of
Ibex.

SECTION 8. TERMINATION

     8.1  Termination  Events.  This  Agreement may be  terminated  prior to the
Closing:

     (a)  by  Castelle  if  Castelle  reasonably   determines  that  the  timely
     satisfaction of any condition set forth in Section 6 has become  impossible
     (other  than as a result of any  failure on the part of  Castelle to comply
     with or perform any  covenant or  obligation  of Castelle set forth in this
     Agreement);

     (b) by Ibex if Ibex reasonably  determines that the timely  satisfaction of
     any condition set forth in Section 7 has become impossible (other than as a
     result  of any  failure  on  the  part  of  Ibex  or any of the  Designated
     Shareholders to comply with or perform any covenant or obligation set forth
     in this  Agreement  or in any other  agreement or  instrument  delivered to
     Castelle);

     (c) by Castelle at or after the Scheduled Closing Time if any condition set
     forth in Section 6 has not been satisfied by the Scheduled Closing Time;

     (d) by Ibex at or after the  Scheduled  Closing Time if any  condition  set
     forth in Section 7 has not been satisfied by the Scheduled Closing Time;

     (e) by Castelle  if the  Closing has not taken place on or before  December
     30,  1996 (other than as a result of any failure on the part of Castelle to
     comply with or perform any covenant or  obligation of Castelle set forth in
     this Agreement);

     (f) by Ibex if the Closing has not taken  place on or before  December  30,
     1996  (other  than as a result of the failure on the part of Ibex or any of
     the  Designated  Shareholders  to comply  with or perform  any  covenant or
     obligation  set  forth  in this  Agreement  or in any  other  agreement  or
     instrument delivered to Castelle); or

     (g) by the mutual consent of Castelle and Ibex.

                                       54


     8.2 Termination Procedures.  If Castelle wishes to terminate this Agreement
pursuant to Section  8.1(a),  Section 8.1(c) or Section  8.1(e),  Castelle shall
deliver to Ibex a written  notice  stating  that  Castelle is  terminating  this
Agreement and setting forth a brief  description  of the basis on which Castelle
is  terminating  this  Agreement.  If Ibex wishes to  terminate  this  Agreement
pursuant to Section 8.1(b), Section 8.1(d) or Section 8.1(f), Ibex shall deliver
to Castelle a written notice stating that Ibex is terminating this Agreement and
setting forth a brief description of the basis on which Ibex is terminating this
Agreement.

     8.3 Effect of  Termination.  If this  Agreement is  terminated  pursuant to
Section 8.1, all further  obligations of the parties under this Agreement  shall
terminate;  provided,  however,  that:  (a) neither Ibex nor  Castelle  shall be
relieved of any  obligation  or liability  arising from any prior breach by such
party of any provision of this Agreement;  (b) the parties shall, in all events,
remain  bound by and  continue  to be  subject  to the  provisions  set forth in
Sections  5.11 and 10; and (c)  Castelle and Ibex shall,  in all events,  remain
bound by and continue to be subject to Section 5.4.

SECTION 9. INDEMNIFICATION, ETC.

     9.1 Survival of Representations, Etc.

     (a) The representations and warranties made by the Designated  Shareholders
     (including  the  representations  and warranties set forth in Section 2 and
     the   representations   and   warranties   set  forth  in  the   Designated
     Shareholders'  Closing  Certificate)  shall  survive  the Closing and shall
     expire on the first  anniversary  of the Closing Date;  provided,  however,
     that the  representations  and  warranties  as to all items  expected to be
     encountered in the audit process shall  terminate  when Castelle  publishes
     its audited  financial  statements  for its fiscal year which  includes the
     Closing Date, and further provided,  however, that if, at any time prior to
     the termination of a specific  representation  or warranty,  any Indemnitee
     (acting in good faith) delivers to Designated Shareholders a written notice
     alleging  the   existence  of  an   inaccuracy  in  or  a  breach  of  such
     representation or warranty made by the Designated Shareholders (and setting
     forth in reasonable detail the basis for such Indemnitee's belief that such
     an inaccuracy or breach may exist) and asserting a claim for recovery under
     Section  9.2 based on such  alleged  inaccuracy  or breach,  then the claim
     asserted in such notice  shall  survive the  termination  of such  specific
     representation  or  warranty  until  such  time as such  claim is fully and
     finally resolved. All representations and warranties made by Castelle shall
     terminate  and  expire  as of the  Effective  Time,  and any  liability  of
     Castelle  with  respect  to  such   representations  and  warranties  shall
     thereupon cease.

     (b) The representations,  warranties, covenants and obligations of Ibex and
     the  Designated  Shareholders,  and the  rights  and  remedies  that may be
     exercised by the Indemnitees, shall not be limited or otherwise affected by
     or as a result of any information  furnished to, or any investigation  made
     by or knowledge of, any of the Indemnitees or any of their Representatives.

                                       55


     (c) For  purposes  of this  Agreement,  each  statement  or  other  item of
     information  set forth in the  Disclosure  Schedule or in any update to the
     Disclosure  Schedule  shall be deemed to be a  representation  and warranty
     made by Ibex and the Designated Shareholders in this Agreement.

     9.2  Indemnification  by  Designated  Shareholders.   From  and  after  the
Effective Time (but subject to Section  9.1(a)),  the  Designated  Shareholders,
severally,  to the extent of each such  shareholder's  pro rata  interest in the
Escrowed Shares,  shall hold harmless and indemnify each of the Indemnitees from
and against, and shall compensate and reimburse each of the Indemnitees for, any
Damages  which are  directly  or  indirectly  suffered or incurred by any of the
Indemnitees  or to which any of the  Indemnitees  may otherwise  become  subject
(regardless of whether or not such Damages relate to any third-party  claim) and
which  arise from or as a result of, or are  directly  or  indirectly  connected
with:  (i) any  inaccuracy  in or breach of any  representation  or warranty set
forth  in  Section  2 or in the  Designated  Shareholders'  Closing  Certificate
(without  giving effect to any "Material  Adverse  Effect" or other  materiality
qualification or any similar qualification contained or incorporated directly or
indirectly in such  representation or warranty,  but giving effect to any update
to the Disclosure  Schedule delivered by Ibex to Castelle prior to the Closing);
(ii) any breach of any covenant or obligation  of Ibex or any of the  Designated
Shareholders  (including  the covenants set forth in Sections 4 and 5); or (iii)
any Legal  Proceeding  relating to any inaccuracy or breach of the type referred
to in clause "(i)" or "(ii)" above (including any Legal Proceeding  commenced by
any Indemnitee for the purpose of enforcing any of its rights under this Section
9).

     9.3 Threshold;  Ceiling. The Designated  Shareholders shall not be required
to  make  any  indemnification  payment  pursuant  to  Section  9.2(a)  for  any
inaccuracy in or breach of any of their representations and warranties set forth
in Section 2 until such time as the total amount of all Damages  (including  the
Damages  arising from such  inaccuracy or breach and all other  Damages  arising
from any other inaccuracies in or breaches of any representations or warranties)
that have been directly or indirectly suffered or incurred by any one or more of
the  Indemnitees,  or to which  any one or more of the  Indemnitees  has or have
otherwise become subject, exceeds $25,000 in the aggregate. (If the total amount
of such Damages exceeds  $25,000,  then the Indemnitees  shall be entitled to be
indemnified  against and compensated and reimbursed for the aggregate  amount of
Damages, including the initial $25,000.)

     9.4 Escrow  Fund.  Notwithstanding  Section  1.9 of this  Agreement  and in
accordance  with the  provisions  of the  Escrow  Agreement  attached  hereto as
Exhibit L (the "Escrow  Agreement),  the Designated  Shareholders  shall deposit
Castelle  Common  Stock  equal to ten  percent  (10%) of the shares of  Castelle
Common  Stock  to be  received  by the  Ibex  shareholders  as a  result  of the
transactions  contemplated  by the Agreement  (the  "Escrowed  Shares") with the
Escrow  Agent to be held  pursuant  to the terms of the Escrow  Agreement  for a
period of one year from the date of the Closing.  Upon compliance with the terms

                                       56


of Section 9 of this Agreement and the Escrow Agreement,  and subject to Section
9.3 above, the Indemnitees shall be entitled to obtain indemnity from the Escrow
Fund for Damages covered by Section 9.

     9.5 No Contribution.  Each Designated  Shareholder waives, and acknowledges
and agrees  that he shall not have and shall not  exercise or assert (or attempt
to exercise or assert),  any right of contribution,  right of indemnity or other
right or  remedy  against  the  Surviving  Corporation  in  connection  with any
indemnification obligation or any other liability to which he may become subject
under or in  connection  with this  Agreement  or the  Designated  Shareholders'
Closing Certificate.

     9.6 Interest.  Any Designated Shareholder who is required to hold harmless,
indemnify,  compensate  or reimburse any  Indemnitee  pursuant to this Section 9
with respect to any Damages shall also be liable to such Indemnitee for interest
on the amount of such Damages (for the period commencing as of the date on which
such  Designated  Shareholder  first received  notice of a claim for recovery by
such Indemnitee and ending on the date on which the liability of such Designated
Shareholder  to  such   Indemnitee  is  fully   satisfied  by  such   Designated
Shareholder) at a floating rate equal to the rate of interest publicly announced
by Bank of  America,  N.T.  & S.A.  from  time  to  time as its  prime,  base or
reference rate.

     9.7  Defense  of Third  Party  Claims.  In the  event of the  assertion  or
commencement  by any Person of any claim or Legal  Proceeding  (whether  against
Castelle  or  against  any  other  Person)  with  respect  to  which  any of the
Designated  Shareholders  may  become  obligated  to hold  harmless,  indemnify,
compensate  or reimburse  any  Indemnitee  pursuant to this Section 9,  Castelle
shall have the right, at its election, to proceed with the defense of such claim
or Legal  Proceeding on its own. If Castelle so proceeds with the defense of any
such claim or Legal Proceeding:

     (a) all reasonable  expenses relating to the defense of such claim or Legal
     Proceeding   shall  be  borne  and  paid   exclusively  by  the  Designated
     Shareholders;

     (b) each  Designated  Shareholder  shall make  available  to  Castelle  any
     documents and materials in his  possession or control that may be necessary
     to the defense of such claim or Legal Proceeding; and

     (c)  Castelle  shall have the right to settle,  adjust or  compromise  such
     claim or Legal Proceeding with the consent of the Designated  Shareholders'
     Agent (as defined in Section 10.1);  provided,  however,  that such consent
     shall not be unreasonably withheld.

Castelle  shall give the  Designated  Shareholders'  Agent prompt  notice of the
commencement of any such Legal Proceeding against Castelle;  provided,  however,
that  any  failure  on  the  part  of  Castelle  to  so  notify  the  Designated
Shareholders'  Agent  shall  not limit any of the  obligations  of the  Designed
Shareholders  under this Section 9 (except to the extent such failure materially
prejudices the defense of such Legal Proceeding).

                                       57


     9.8 Exercise of Remedies by Indemnitees Other Than Castelle.  No Indemnitee
(other  than  Castelle  or any  successor  thereto or assign  thereof)  shall be
permitted to assert any indemnification claim or exercise any other remedy under
this  Agreement  unless  Castelle (or any successor  thereto or assign  thereof)
shall have  consented  to the  assertion  of such  indemnification  claim or the
exercise of such other remedy. Such consent shall be evidenced by the submission
by Castelle of such claim to the Designated Shareholders' Representative.

     9.9  Claims  Against   Consideration.   Upon  delivery  to  the  Designated
Shareholders' Agent (with a copy to Escrow Agent, as such term is defined in the
form of Escrow Agreement  attached hereto as Exhibit L) of a certificate  signed
by any officer of Castelle (an "Officer's Certificate"):

     (a) stating that an Indemnitee  has paid or properly  accrued or reasonably
     anticipates  that it will have to pay or  accrue  Damages  in an  aggregate
     stated amount to which an  Indemnitee is entitled to indemnity  pursuant to
     this Agreement (the "Claim Amount"); and

     (b)  specifying  in  reasonable  detail  the  individual  items of  Damages
     included  in the  amount  so  stated,  the date  each such item was paid or
     properly  accrued,  or the basis for such  anticipated  liability,  and the
     nature of the  misrepresentation,  breach of warranty,  legal proceeding or
     claim to which such item is related,  the  Indemnitee  shall be entitled to
     indemnification for such Damages.

     (c) Castelle and the  Indemnitees  shall use reasonable  efforts to provide
     such Officer's  Certificate  within a reasonable time following the date of
     payment,  accrual or reasonable  anticipation of liability, as the case may
     be.

     9.10 Objections to Claims.  For a period of twenty (20) business days after
delivery of any Officer's Certificate to the Designated Shareholders' Agent, the
Indemnitees  shall not take further actions to seek  indemnification.  After the
expiration of such twenty (20 business day period,  the Indemnitees shall become
irrevocably entitled to seek indemnification  under the terms of this Agreement,
if the Designated  Shareholders' Agent shall not have objected in writing to the
claim  made in the  Officer's  Certificate,  and shall not have  delivered  such
written objection to Castelle prior to the expiration of such ten day period.

     9.11 Resolution of Conflicts; Arbitration

     (a) In case the Designated Shareholders' Agent so objects in writing to the
     indemnity of the  Indemnitees in respect of any claim or claims made in any
     Officer's   Certificate,   the  Designated   Shareholders'  Agent  and  the
     Indemnitees  shall  attempt  in good  faith to agree upon the rights of the
     respective  parties with respect to each of such claims.  If the Designated
     Shareholders'  Agent and the  Indemnitees  so agree,  a memorandum  setting
     forth such agreement  shall be prepared and signed by the  Indemnitees  and
     the Designated  Shareholders'  Agent,  which agreement shall be binding and
     conclusive on the Indemnitees and the Designated  Shareholders (a "Response
     Notice").

                                       58


     (b) If no such  agreement  can be reached  after  good  faith  negotiation,
     either the  Indemnitees  or the Designated  Shareholders'  Agent may demand
     arbitration  of the matter by serving a written  demand for  arbitration on
     the other (the "Demand for Arbitration");  provided,  however,  that if the
     amount of the Damages is at issue in pending litigation with a third party,
     arbitration shall not be commenced until such amount is ascertained or both
     parties agree to arbitration. The decision of the arbitrator so selected as
     to the validity and amount of any claim in such Officer's Certificate shall
     be  binding  and  conclusive   upon  the  Indemnitees  and  the  Designated
     Shareholders.

     (c) Any such arbitration shall be held in San Francisco,  California before
     the single arbitrator under the commercial arbitration rules then in effect
     of the American Arbitration Association ("AAA"), except as modified herein.

          (i) Selection. The single arbitrator shall have at least five years of
          experience in commercial dispute  resolution.  The arbitrator shall be
          selected  by  mutual   agreement   between  the  Indemnitees  and  the
          Designated  Shareholders'  Agent,  but if they  cannot  agree upon the
          selection  within ten days after Demand for Arbitration is given,  the
          selection shall occur as follows: (a) the party initiating arbitration
          shall obtain a list of seven arbitrators,  each of whom shall have the
          requisite experience described above, from the San Francisco office of
          the AAA and simultaneously give a copy thereof to the other party; (b)
          each party  alternately  shall strike three names from the list,  with
          the other party striking first; and (c) the last remaining  arbitrator
          shall be deemed selected by the parties as a single  arbitrator.  If a
          party  refuses for ten or more days to complete  this  selection,  the
          other party shall select a name from the list to be the  arbitrator at
          the end of such ten day period.

          (ii)  Procedure.  Arbitration  shall  be  conducted  in the  following
          manner:

               (a) If the  responding  party  desires to file a response  and/or
               counterclaim to the Demand for Arbitration,  it must do so within
               ten calendar  days after  service of the Demand for  Arbitration.
               Any response to a  counterclaim  shall be filed and served within
               ten calendar days after service of the counterclaim,  but no such
               response shall be required.  A failure to file a counterclaim  or
               response will not operate to delay the arbitration proceedings.

               (b)  After  the  filing  of  the  Demand  for  Arbitration,   any
               counterclaim  and any  responses  thereto,  no further  claims or
               counterclaims  may be made except by order of the arbitrator made
               on a duly noticed motion to the arbitrator.

               (c) The arbitration  shall commence as soon as possible but in no
               event earlier than ten days after selection of the arbitrator and
               in no event later than 30 days  following  the filing of the last
               response  under (b)  above,  or if there is none,  following  the
               Demand for Arbitration.

                                       59


               (d)   the   Indemnitees   and   the   Designated    Shareholders'
               Representative  (acting on behalf of the Designated  Shareholders
               and being  entitled to  reimbursement  under  Section 10.1) shall
               each pay an equal  share of the fees and  expenses  of any person
               serving  as  an  arbitrator.   The  arbitrator,  in  his  or  her
               discretion,  shall be authorized to determine  whether a party is
               the prevailing  party,  and if so, to award that prevailing party
               reimbursement  for  its  share  of  the  costs  and  fees  of the
               arbitrator, and reimbursement for its reasonable attorneys' fees,
               disbursements and costs incurred in such arbitration.

               (e) The arbitrator,  upon application of any party,  shall hold a
               pre-hearing  conference  with  the  parties  for the  purpose  of
               narrowing  the  issues,   establishing   a  discovery   schedule,
               arranging  an  acceptable   procedure  for  any  law  and  motion
               proceedings   and  in  all  respects   arranging   for  the  most
               expeditious  hearing  possible of the  matters in  dispute.  Such
               conference shall be held as soon as possible following  selection
               of the arbitrator,  any counterclaim  thereto and any response to
               such  counterclaim  (if any),  but in no event later than 20 days
               following the filing of the last response under (b) above,  or if
               there is none, following the Demand for Arbitration.

               (f) Discovery shall be conducted in accordance with Part 3, Title
               9,  Chapter  3 of the  California  Code of  Civil  Procedure,  as
               amended from time to time.

               (g) Except as  expressly  provided in this  Section  9.11.3,  the
               arbitration   hearing   shall  be  conducted   according  to  the
               discretion  of the  arbitrator.  Judicial  rules  relating to the
               order of proof,  the conduct of the hearing and the  presentation
               and admissibility of evidence need not be followed.  Any relevant
               information, including hearsay, may be admitted by the arbitrator
               regardless  of its  admissibility  as evidence in court,  but the
               arbitrator  also shall be  authorized  to exclude  evidence.  The
               parties shall have the power to subpoena  witnesses to attend the
               arbitration   hearing   pursuant  to  California  Code  of  Civil
               Procedure Section 1282.6. The arbitrator shall have full power to
               give such  directions  and to make such  orders in the conduct of
               the arbitration, including setting pre-arbitration procedures and
               scheduling any motions to correct or amend the arbitration award,
               as he or she deems just and appropriate,  including  specifically
               the  right  to make  such  reasonable  extensions  of time as the
               arbitrator  determines  are necessary to  accommodate  discovery,
               prearbitration procedures,  motions, settlement discussions,  and
               other such matters, but not in any event to exceed 30 days in the
               aggregate,  from the date the arbitration was otherwise scheduled
               to commence as provided above.

               (h) The arbitrator  shall,  within five days after the conclusion
               of the arbitration hearing,  issue a written decision and a brief
               written  statement  of  decision  describing  the reasons for the
               decision,  including the calculation of any compensatory  damages
               awarded.

               (i) Absent the filing of an  application to correct or vacate the
               arbitration  award as provided  in section (j) below,  each party
               shall fully  perform  and  satisfy  the terms of the  arbitration
               decision within 15 days of the service of the decision.

                                       60


               (j) The  decision  of the  arbitrator  shall be final and binding
               upon the parties  without appeal or review except as permitted by
               California law; provided,  however, that either party may, within
               ten days of the service of the decision,  file an  application to
               correct or vacate the arbitration  award or an application for de
               novo  review on all  questions  of law based on the  arbitrator's
               finding  of  fact  (which  are  deemed  for  such  purpose  to be
               stipulated by the parties),  in either case under California Code
               of Civil  Procedure  Section  1285 et seq. Any party may apply to
               any court of competent jurisdiction for confirmation and entry of
               judgment based on said award.  In connection with any application
               to review  questions of law or to confirm,  correct or vacate the
               arbitration  award, any appeal of any order rendered  pursuant to
               any such application, or any other action required to enforce the
               arbitration  award,  the  prevailing  party  shall be entitled to
               recover its reasonable  attorneys' fees,  disbursements and costs
               incurred in such post-award activities.

     (d) The arbitrator  shall not have the power to vary the provisions of this
     Agreement.  The parties hereby  irrevocably waive, and the arbitrator shall
     have no power to award,  any  damages  for pain and  suffering  or punitive
     damages.

     (e) By signing  below,  each party  acknowledges  that (a) the  arbitration
     provisions  of this  Agreement  require the party to give up rights to have
     the dispute  litigated  in a court or jury trial,  and to give up rights to
     discovery  and most grounds for appeal,  and (b) the party may be compelled
     to arbitrate if the party refuses to do so.

SECTION 10. MISCELLANEOUS PROVISIONS

     10.1 Designated  Shareholders'  Agent. The Designated  Shareholders  hereby
irrevocably  appoint  Ney Grant as their  agent for  purposes  of Section 9 (the
"Designated  Shareholders' Agent"), and Ney Grant hereby accepts his appointment
as the  Designated  Shareholders'  Agent.  Castelle  shall be  entitled  to deal
exclusively with the Designated  Shareholders'  Agent on all matters relating to
Section 9, and shall be entitled to rely conclusively  (without further evidence
of any kind whatsoever) on any document  executed or purported to be executed on
behalf of any Designated Shareholder by the Designated  Shareholders' Agent, and
on any other action  taken or purported to be taken on behalf of any  Designated
Shareholder by the Designated  Shareholders'  Agent,  as fully binding upon such
Designated Shareholder.  If the Designated Shareholders' Agent shall die, become
disabled or otherwise be unable to fulfill his  responsibilities as agent of the
Designated Shareholders, then the Designated Shareholders shall, within ten days
after  such  death or  disability,  appoint  a  successor  agent  and,  promptly
thereafter,  shall notify Castelle of the identity of such  successor.  Any such
successor  shall  become the  "Designated  Shareholders'  Agent" for purposes of
Section 9 and this  Section  10.1.  The  Designated  Shareholders'  Agent  shall
receive  no  compensation  for his  services,  but shall be  reimbursed  for his
reasonable  out-of-pocket expenses by the Designated  Shareholders in proportion
to the  number of shares  of  Castelle  Common  Stock  received  by each of them
pursuant  to  this  Agreement.   If  for  any  reason  there  is  no  Designated
Shareholders'  Agent  at any  time,  all  references  herein  to the  Designated
Shareholders' Agent shall be deemed to refer to the Designated Shareholders.

                                       61


     10.2 Further  Assurances.  Each party hereto shall  execute and cause to be
delivered to each other party hereto such instruments and other  documents,  and
shall take such other actions, as such other party may reasonably request (prior
to, at or after the Closing) for the purpose of carrying out or  evidencing  any
of the transactions contemplated by this Agreement.

     10.3 Fees and Expenses. Each party to this Agreement shall bear and pay all
fees,  costs and expenses  (including  legal fees and accounting fees) that have
been  incurred  or that  are  incurred  by such  party  in  connection  with the
transactions  contemplated  by this  Agreement,  including  all fees,  costs and
expenses  incurred  by such  party in  connection  with or by  virtue of (a) the
investigation  and review  conducted  by Castelle and its  Representatives  with
respect to Ibex's  business (and the  furnishing of  information to Castelle and
its  Representatives in connection with such investigation and review),  (b) the
negotiation,  preparation and review of this Agreement (including the Disclosure
Schedule) and all agreements,  certificates,  opinions and other instruments and
documents  delivered  or to be  delivered in  connection  with the  transactions
contemplated by this Agreement, (c) the preparation and submission of any filing
or  notice  required  to be  made  or  given  in  connection  with  any  of  the
transactions  contemplated by this  Agreement,  and the obtaining of any Consent
required to be obtained in connection with any of such transactions, and (d) the
consummation  of the Merger;  provided,  however,  that Castelle shall reimburse
Ibex for the first $25,000 of audit fees, costs and expenses invoiced by Coopers
& Lybrand  LLP and  incurred  by Ibex in the audit by  Coopers & Lybrand  LLP of
Ibex's fiscal years ended December 31, 1995 and 1994, as well as one-half of any
additional audit fees, costs and expenses invoiced by Coopers & Lybrand LLP.

     10.4  Attorneys'  Fees.  If any  action  or  proceeding  relating  to  this
Agreement  or the  enforcement  of any  provision  of this  Agreement is brought
against  any party  hereto,  the  prevailing  party shall be entitled to recover
reasonable  attorneys' fees, costs and  disbursements  (in addition to any other
relief to which the prevailing party may be entitled).

     10.5 Notices. Any notice or other communication required or permitted to be
delivered  to any party  under this  Agreement  shall be in writing and shall be
deemed  properly  delivered,  given and received  when  delivered  (by hand,  by
registered  mail, by courier or express delivery service or by facsimile) to the
address or facsimile  telephone  number set forth beneath the name of such party
below (or to such other  address  or  facsimile  telephone  number as such party
shall have specified in a written notice given to the other parties hereto):

               if to Castelle:

                      Attention:  President
                      Castelle
                      3255-3 Scott Boulevard
                      Santa Clara, California  95054
                      Facsimile #:  (408) 654-4699

                                       62


               with a copy to:

                      Samuel M. Livermore
                      Cooley Godward Castro Huddleson & Tatum
                      One Maritime Plaza, Suite 2000
                      San Francisco, California 94111
                      Facsimile #:  (415) 951-3698

               if to Ibex:

                      Attention:  President
                      Ibex Technologies, Inc.
                      4921 R.J. Mathews Pkwy.
                      El Dorado Hills, California 95762
                      Facsimile #:  (916) 939-8899

               with a copy to:

                      Gilles S. Attia
                      Graham & James LLP
                      400 Capitol Mall, 24th Floor
                      Sacramento, California  95814
                      Facsimile #:  (916) 441-6700

               if to any of the Designated Shareholders:

                      Ney Grant
                      2725 Romer Boulevard
                      Pollock Pines, California  95726
                      Facsimile #:  (916) 647-2055

               if to Teodoro Gimenez, Tucha Limited, or Newark Holding S.A.:

                      Teodoro Ramos Gimenez
                      Tecom Sistemas
                      Rua Jeronimo de Lemos, 162
                      Rio de Janeiro, RJ
                      20560-090 Brazil
                      Facsimile #:  011-55-21-577-1125

                                       63


               with a copy to:

                      Peter N. Barnes-Brown
                      Morse, Barnes-Brown & Pendleton, P.C.
                      Reservoir Place
                      1601 Trapelo Road
                      Waltham, Massachusetts  02154
                      Facsimile #:  (617) 622-5933

     10.6 Confidentiality. Without limiting the generality of anything contained
in Section  5.4,  on and at all times after the Closing  Date,  each  Designated
Shareholder shall keep confidential,  and shall not use or disclose to any other
Person,  any  non-public  document  or  other  non-public  information  in  such
Designated  Shareholder's  possession  that  relates to the  business of Ibex or
Castelle.

     10.7 Time of the Essence. Time is of the essence of this Agreement.

     10.8 Headings.  The underlined headings contained in this Agreement are for
convenience  of  reference  only,  shall  not be  deemed  to be a part  of  this
Agreement and shall not be referred to in connection  with the  construction  or
interpretation of this Agreement.

     10.9 Counterparts.  This Agreement may be executed in several counterparts,
each of  which  shall  constitute  an  original  and all of  which,  when  taken
together, shall constitute one agreement.

     10.10 Governing Law. This Agreement shall be construed in accordance  with,
and governed in all respects  by, the internal  laws of the State of  California
(without giving effect to principles of conflicts of laws).

     10.11  Successors and Assigns.  This Agreement  shall be binding upon: Ibex
and its successors and assigns (if any); the Designated  Shareholders  and their
respective personal representatives,  executors, administrators, estates, heirs,
successors and assigns (if any); and Castelle and its successors and assigns (if
any).  This Agreement shall inure to the benefit of: Ibex;  Ibex's  shareholders
(to the extent set forth in Section  1.5);  the holders of assumed  Ibex Options
(to the  extent  set forth in  Section  1.6);  Castelle;  the other  Indemnitees
(subject to Section 9.8); and the respective  successors and assigns (if any) of
the foregoing. Subsequent to the Closing Date, Castelle may freely assign any or
all of its rights under this  Agreement  (including its  indemnification  rights
under Section 9), in whole or in part, to any other Person without obtaining the
consent or approval of any other party hereto or of any other Person.

     10.12 Remedies Cumulative; Specific Performance. The rights and remedies of
the parties  hereto shall be cumulative  (and not  alternative).  The parties to
this  Agreement  agree that, in the event of any breach or threatened  breach by
any party to this Agreement of any covenant,  obligation or other  provision set
forth in this  Agreement  for the benefit of any other party to this  Agreement,

                                       64


such other party shall be entitled  (in addition to any other remedy that may be
available to it) to (a) a decree or order of specific performance or mandamus to
enforce the  observance and  performance  of such covenant,  obligation or other
provision, and (b) an injunction restraining such breach or threatened breach.

     10.13 Waiver.

     (a) No  failure  on the part of any Person to  exercise  any power,  right,
     privilege or remedy under this  Agreement,  and no delay on the part of any
     Person in  exercising  any power,  right,  privilege  or remedy  under this
     Agreement,  shall  operate as a waiver of such power,  right,  privilege or
     remedy;  and no  single  or  partial  exercise  of any such  power,  right,
     privilege or remedy shall preclude any other or further exercise thereof or
     of any other power, right, privilege or remedy.

     (b) No Person shall be deemed to have waived any claim  arising out of this
     Agreement,  or any power, right,  privilege or remedy under this Agreement,
     unless the  waiver of such  claim,  power,  right,  privilege  or remedy is
     expressly set forth in a written  instrument duly executed and delivered on
     behalf of such Person;  and any such waiver shall not be applicable or have
     any effect except in the specific instance in which it is given.

     10.14 Amendments.  This Agreement may not be amended,  modified, altered or
supplemented  other  than by means of a written  instrument  duly  executed  and
delivered on behalf of all of the parties hereto.

     10.15 Severability.  In the event that any provision of this Agreement,  or
the  application  of any such  provision to any Person or set of  circumstances,
shall be  determined  to be  invalid,  unlawful,  void or  unenforceable  to any
extent,  the remainder of this Agreement,  and the application of such provision
to Persons or circumstances  other than those as to which it is determined to be
invalid,  unlawful,  void or  unenforceable,  shall not be impaired or otherwise
affected and shall  continue to be valid and  enforceable  to the fullest extent
permitted by law.

     10.16 Parties in Interest.  Except for the  provisions of Sections 1.5, 1.6
and 9, none of the  provisions  of this  Agreement  is  intended  to provide any
rights or  remedies  to any  Person  other  than the  parties  hereto  and their
respective successors and assigns (if any).

     10.17 Entire Agreement. This Agreement and the other agreements referred to
herein set forth the entire  understanding of the parties hereto relating to the
subject  matter  hereof and  thereof  and  supersede  all prior  agreements  and
understandings  among or between  any of the  parties  relating  to the  subject
matter hereof and thereof.

     10.18 Construction.

     (a) For  purposes of this  Agreement,  whenever the context  requires:  the
     singular  number shall  include the plural,  and vice versa;  the masculine
     gender shall include the feminine and neuter  genders;  the feminine gender
     shall include the masculine and neuter genders; and the neuter gender shall
     include the masculine and feminine genders.

                                       65


     (b) The parties  hereto agree that any rule of  construction  to the effect
     that ambiguities are to be resolved against the drafting party shall not be
     applied in the construction or interpretation of this Agreement.

     (c) As used in this  Agreement,  the words "include" and  "including,"  and
     variations  thereof,  shall not be deemed  to be terms of  limitation,  but
     rather shall be deemed to be followed by the words "without limitation."

     (d) Except as otherwise  indicated,  all  references  in this  Agreement to
     "Sections"  and  "Exhibits"  are  intended  to  refer to  Sections  of this
     Agreement and Exhibits to this Agreement.


                                       66



     The parties  hereto have caused this Agreement to be executed and delivered
as of August 22, 1996.

                            CASTELLE,
                            a California corporation



                            By: /s/ Arthur H. Bruno







                            IBEX TECHNOLOGIES, INC.,
                            a California corporation



                            By: /s/ Ney Grant



                               /s/ Betsy Grey-Grant



                               /s/ Clovis Mattos



                               /s/ Curtis Powell



                               /s/ Teodoro Ramos Giminez



                               /s/ on behalf of Newark Holdings S.A.



                               /s/ on behalf of Tucha Limited


                                       67



                                   EXHIBIT A-1

                             DESIGNATED SHAREHOLDERS





Name
Ney Grant and Betsy Gray-Grant
Clovis Mattos
Curtis Powell



                                       68




                                   EXHIBIT A-2

                              SIGNING SHAREHOLDERS



Tucha Limited

Newark Holding S.A.

Teodoro Ramos Gimenez
















     Includes  those persons  identified as Designated  Shareholders  on Exhibit
A-1.

                                       69




                                    EXHIBIT B

                               CERTAIN DEFINITIONS



     For purposes of the Agreement (including this Exhibit B):

     Acquisition   Transaction.   "Acquisition   Transaction"   shall  mean  any
transaction involving:

     (a) the sale,  license,  disposition  or  acquisition  of all or a material
     portion of Ibex's business or assets;

     (b) the issuance,  disposition  or  acquisition of (i) any capital stock or
     other equity  security of Ibex (other than common stock issued to employees
     of  Ibex,   upon  exercise  of  Ibex  Options  or  otherwise,   in  routine
     transactions  in accordance with Ibex's past  practices),  (ii) any option,
     call, warrant or right (whether or not immediately  exercisable) to acquire
     any  capital  stock or other  equity  security  of Ibex  (other  than stock
     options granted to employees of Ibex in routine  transactions in accordance
     with  Ibex's  past  practices),  or  (iii)  any  security,   instrument  or
     obligation that is or may become  convertible  into or exchangeable for any
     capital stock or other equity security of Ibex; or

     (c) any merger,  consolidation,  business  combination,  reorganization  or
     similar transaction involving Ibex.

     Agreement.  "Agreement"  shall  mean the  Agreement  and Plan of Merger and
Reorganization  to which this Exhibit B is attached  (including  the  Disclosure
Schedule), as it may be amended from time to time.

     Ibex Contract.  "Ibex Contract" shall mean any Contract:  (a) to which Ibex
is a party;  (b) by which Ibex or any of its  assets is or may  become  bound or
under which Ibex has, or may become  subject  to, any  obligation;  or (c) under
which Ibex has or may acquire any right or interest.

     Ibex Proprietary Asset. "Ibex Proprietary Asset" shall mean any Proprietary
Asset owned by or licensed to Ibex or otherwise used by Ibex.

     Consent.  "Consent"  shall  mean  any  approval,   consent,   ratification,
permission, waiver or authorization (including any Governmental Authorization).

     Contract.  "Contract"  shall  mean any  written,  oral or other  agreement,
contract,  subcontract,   lease,  understanding,   instrument,  note,  warranty,
insurance policy,  benefit plan or legally binding  commitment or undertaking of
any nature.

                                       70


     Damages.  "Damages"  shall  include any loss,  damage,  injury,  decline in
value, lost opportunity,  liability, claim, demand, settlement, judgment, award,
fine, penalty,  Tax, fee (including  reasonable  attorneys' fees),  charge, cost
(including costs of investigation) or expense of any nature.

     Disclosure Schedule.  "Disclosure  Schedule" shall mean the schedule (dated
as of the date of the Agreement) delivered to Castelle on behalf of Ibex and the
Designated Shareholders.

     Encumbrance.  "Encumbrance"  shall  mean any lien,  pledge,  hypothecation,
charge,  mortgage,   security  interest,   encumbrance,   claim,   infringement,
interference,  option,  right  of first  refusal,  preemptive  right,  community
property interest or restriction of any nature (including any restriction on the
voting of any security, any restriction on the transfer of any security or other
asset,  any restriction on the receipt of any income derived from any asset, any
restriction  on the use of any  asset  and any  restriction  on the  possession,
exercise or transfer of any other attribute of ownership of any asset).

     Entity.  "Entity"  shall mean any  corporation  (including  any  non-profit
corporation),   general  partnership,  limited  partnership,  limited  liability
partnership,  joint  venture,  estate,  trust,  company  (including  any limited
liability   company  or  joint  stock  company),   firm  or  other   enterprise,
association, organization or entity.

     Exchange  Act.  "Exchange  Act" shall mean the  Securities  Exchange Act of
1934, as amended.

     Government Bid. "Government Bid" shall mean any quotation,  bid or proposal
submitted  to  any  Governmental  Body  or  any  proposed  prime  contractor  or
higher-tier subcontractor of any Governmental Body.

     Government Contract.  "Government  Contract" shall mean any prime contract,
subcontract,  letter  contract,  purchase  order or delivery  order  executed or
submitted to or on behalf of any  Governmental  Body or any prime  contractor or
higher-tier  subcontractor,  or under  which any  Governmental  Body or any such
prime  contractor  or  subcontractor  otherwise  has or may acquire any right or
interest.

     Governmental  Authorization.  "Governmental  Authorization" shall mean any:
(a)   permit,   license,   certificate,    franchise,   permission,   clearance,
registration, qualification or authorization issued, granted, given or otherwise
made available by or under the authority of any Governmental Body or pursuant to
any Legal  Requirement;  or (b) right under any Contract  with any  Governmental
Body.

     Governmental Body.  "Governmental Body" shall mean any: (a) nation,  state,
commonwealth,  province,  territory,  county,  municipality,  district  or other
jurisdiction of any nature; (b) federal,  state,  local,  municipal,  foreign or
other  government;  or (c) governmental or  quasi-governmental  authority of any

                                       71


nature (including any governmental  division,  department,  agency,  commission,
instrumentality,  official,  organization, unit, body or Entity and any court or
other tribunal).

     Indemnitees.  "Indemnitees" shall mean the following Persons: (a) Castelle;
(b) Castelle's current and future affiliates; (c) the respective Representatives
of the  Persons  referred  to in  clauses  "(a)"  and "(b)"  above;  and (d) the
respective  successors and assigns of the Persons  referred to in clauses "(a)",
"(b)" and "(c)" above; provided, however, that the Designated Shareholders shall
not be deemed to be "Indemnitees."

     Legal  Proceeding.   "Legal  Proceeding"  shall  mean  any  action,   suit,
litigation,    arbitration,   proceeding   (including   any   civil,   criminal,
administrative, investigative or appellate proceeding), hearing, inquiry, audit,
examination  or  investigation  commenced,  brought,  conducted  or  heard by or
before,  or otherwise  involving,  any court or other  Governmental  Body or any
arbitrator or arbitration panel.

     Legal  Requirement.  "Legal  Requirement"  shall mean any  federal,  state,
local,  municipal,  foreign or other law,  statute,  constitution,  principle of
common law, resolution, ordinance, code, edict, decree, rule, regulation, ruling
or requirement issued, enacted, adopted,  promulgated,  implemented or otherwise
put into effect by or under the authority of any Governmental Body.

     Material Adverse Effect. A violation or other matter will be deemed to have
a  "Material  Adverse  Effect"  on  Ibex  if  such  violation  or  other  matter
(considered together with all other matters that would constitute  exceptions to
the  representations  and  warranties  set  forth  in  the  Agreement  or in the
Designated  Shareholders'  Closing Certificate but for the presence of "Material
Adverse   Effect"  or  other   materiality   qualifications,   or  any   similar
qualifications,  in such  representations  and warranties) would have a material
adverse effect on Ibex's business,  condition, assets, liabilities,  operations,
financial performance or prospects.

     Person. "Person" shall mean any individual, Entity or Governmental Body.

     Proprietary Asset.  "Proprietary Asset" shall mean any: (a) patent,  patent
application,   trademark   (whether   registered  or  unregistered),   trademark
application,  trade  name,  fictitious  business  name,  service  mark  (whether
registered  or  unregistered),  service  mark  application,  copyright  (whether
registered  or  unregistered),   copyright   application,   maskwork,   maskwork
application,  trade secret, know-how, customer list, franchise, system, computer
software, computer program, invention,  design, blueprint,  engineering drawing,
proprietary  product,  technology,   proprietary  right  or  other  intellectual
property  right or intangible  asset;  or (b) right to use or exploit any of the
foregoing.

     Representatives.   "Representatives"   shall  mean   officers,   directors,
employees, agents, attorneys, accountants, advisors and representatives.

     SEC. "SEC" shall mean the United States Securities and Exchange Commission.

                                       72


     Securities Act.  "Securities Act" shall mean the Securities Act of 1933, as
amended.

     Tax.  "Tax" shall mean any tax  (including  any income tax,  franchise tax,
capital gains tax, gross receipts tax,  value-added tax, surtax,  excise tax, ad
valorem tax, transfer tax, stamp tax, sales tax, use tax, property tax, business
tax, withholding tax or payroll tax), levy, assessment,  tariff, duty (including
any  customs  duty),  deficiency  or  fee,  and any  related  charge  or  amount
(including any fine, penalty or interest),  imposed, assessed or collected by or
under the authority of any Governmental Body.

     Tax Return.  "Tax Return" shall mean any return  (including any information
return),   report,   statement,   declaration,   estimate,   schedule,   notice,
notification, form, election, certificate or other document or information filed
with or  submitted  to,  or  required  to be filed  with or  submitted  to,  any
Governmental Body in connection with the determination,  assessment,  collection
or payment of any Tax or in connection with the  administration,  implementation
or enforcement of or compliance with any Legal Requirement relating to any Tax.

                                       73




                                   EXHIBIT C-1

                           FORM OF AFFILIATE AGREEMENT

                                       74




                               AFFILIATE AGREEMENT



     THIS AFFILIATE  AGREEMENT  ("Agreement") is being executed and delivered as
of August __, 1996, by the parties identified on Exhibit A (each, an "Affiliate"
and  collectively,  the  "Affiliates")  and CASTELLE,  a California  corporation
("Castelle").

                                    RECITALS

     A. The Affiliates are shareholders of IBEX TECHNOLOGIES, INC., a California
corporation (the "Company").

     B. Castelle,  the Company, the Affiliates and certain other shareholders of
the Company have entered into an Agreement and Plan of  Reorganization  dated as
of August 22, 1996 (the "Reorganization  Agreement") providing for the merger of
the Company with and into Castelle (the "Merger").  The Reorganization Agreement
contemplates  that, upon consummation of the Merger,  all outstanding  shares of
capital stock of the Company will be converted  into the right to receive shares
of  common  stock of  Castelle  ("Castelle  Common  Stock").  It is  accordingly
contemplated that the Affiliates will receive shares of Castelle Common Stock in
the Merger.

     C. Each  Affiliate  may be deemed to be an  "affiliate"  of the Company for
purposes of (i) the  restrictions  on resale imposed by  interpretations  of the
staff of the  Securities  and Exchange  Commission  (the "SEC") in  transactions
exempted from  registration  under the  Securities  Act of 1933, as amended (the
"Securities  Act"), and (ii) determining  Castelle's  eligibility to account for
the Merger as a "pooling of interests" under Accounting  Series Releases 130 and
135, as amended, of the SEC.

                                    AGREEMENT

     1.  Representations and Warranties.  The Affiliates severally represent and
warrant to Castelle as follows:

     (a) Each  Affiliate  is the  holder and  beneficial  owner of the number of
     shares of the Company's capital stock set forth under Affiliate's signature
     below (the "Shares"), and Affiliate has good and valid title to the Shares,
     free and clear of any liens, pledges,  security interests,  adverse claims,
     equities,  options, proxies,  charges,  encumbrances or restrictions of any
     nature.

     (b) Each  Affiliate has carefully  read this  Agreement,  and has discussed
     with counsel to the extent Affiliate felt necessary the limitations imposed
     on  Affiliate's  ability  to sell,  transfer  or  otherwise  dispose of the
     Shares, the shares of Castelle Common Stock that Affiliate is to receive in
     the Merger (the "Castelle Shares") and other shares of the capital stock of
     the Company or Castelle.  Affiliate fully  understands the limitations this

                                       75


     Agreement  places upon Affiliate's  ability to sell,  transfer or otherwise
     dispose of the Shares,  and the Castelle Shares and other shares of capital
     stock of the Company or Castelle.

     (c) Each Affiliate  understands  that the  representations,  warranties and
     covenants  set forth herein will be relied upon by Castelle and its counsel
     and  accountants  for purposes of  determining  Castelle's  eligibility  to
     account  for the  Merger as a  "pooling  of  interests,"  for  purposes  of
     determining whether to proceed with the Merger and for other purposes.

     2. Prohibition Against Transfer. Each Affiliate agrees that:

     (a) until such time as the  Reorganization  Agreement is validly terminated
     in accordance with its terms,  such Affiliate  shall not sell,  transfer or
     otherwise  dispose of, or reduce  Affiliate's  interest in or risk relating
     to, (i) any  capital  stock of the  Company  (including  the Shares and any
     additional  shares of capital  stock of the Company  acquired by Affiliate,
     whether upon exercise of a stock option or  otherwise),  or (ii) any option
     to purchase any capital stock of the Company,  except  pursuant to and upon
     consummation of the Merger;

     (b)  during the  period  from the date on which the  Merger is  consummated
     through the date on which  financial  results  covering at least 30 days of
     post-Merger  combined  operations  of Castelle  and the  Company  have been
     published  by Castelle  (within the meaning of the  applicable  "pooling of
     interests" accounting requirements),  Affiliate shall not sell, transfer or
     otherwise  dispose of, or reduce  Affiliate's  interest in or risk relating
     to, (i) any shares of Castelle Common Stock (including the Castelle Shares)
     and any additional  shares of Castelle  Common Stock acquired by Affiliate,
     whether upon exercise of a stock option or otherwise, or (ii) any option to
     purchase shares of Castelle Common Stock; and

     (c) without  limiting the  generality  of the  foregoing,  or the effect of
     clause (b) of this Section 2, Affiliate shall not effect any sale, transfer
     or other disposition of the Castelle Shares unless:

          (i) such sale,  transfer or other  disposition  is made in  conformity
          with the  volume  and  other  requirements  of Rule  145(d)  under the
          Securities Act, as evidenced by a broker's letter and a representation
          letter executed by Affiliate, each stating that such requirements have
          been met;

          (ii) counsel  reasonably  satisfactory  to Castelle shall have advised
          Castelle in a written opinion letter upon which Castelle may rely that
          such  sale,   transfer  or  other  disposition  will  be  exempt  from
          registration under the Securities Act;

          (iii) such sale,  transfer or other  disposition  has been  registered
          under the Securities Act; or

          (iv) an  authorized  representative  of the SEC  shall  have  rendered
          written  advice to  Affiliate to the effect that the SEC would take no

                                       76


          action,  or that the staff of the SEC would not recommend that the SEC
          take action,  with respect to such  proposed  sale,  transfer or other
          disposition,  and a copy of such written  advice and all other related
          communications with the SEC shall have been delivered to Castelle.

     For  purposes  of Section  2(c)(ii),  counsel  reasonably  satisfactory  to
Castelle shall include, in the case of sales, transfers or other dispositions by
Tucha Limited,  Newark  Holding S.A. and Teodoro Ramos Gimenez,  the law firm of
Morse, Barnes-Brown & Pendleton, P.C., presently in Waltham, Massachusetts.

     3. Stop Transfer Instructions.

     (a) Each Affiliate  acknowledges and agrees that stop transfer instructions
     will be given to  Castelle's  transfer  agent with  respect to the Castelle
     Shares and with respect to any shares of Castelle  Common Stock acquired by
     Affiliate  upon any  exercise of any option to purchase  shares of Castelle
     Common  Stock,   and  that  there  will  be  placed  on  the   certificates
     representing  such shares of  Castelle  Common  Stock or any  substitutions
     thereof a legend, stating in substance:

        THE SHARES REPRESENTED BY THIS CERTIFICATE ARE RESTRICTED AND MAY
        ONLY BE TRANSFERRED IN ACCORDANCE WITH THE TERMS OF AN AGREEMENT
        DATED AS OF AUGUST __, 1996, BETWEEN THE REGISTERED HOLDER HEREOF
            AND CASTELLE, A COPY OF WHICH AGREEMENT IS ON FILE AT THE
                         PRINCIPAL OFFICES OF CASTELLE."

     (b) Castelle agrees that such stop transfer  instructions  and legends will
     be removed with respect to shares of Castelle  Common Stock at such time as
     Castelle is reasonably satisfied that the restrictions on resale imposed by
     interpretations  of the staff of the Commission are no longer applicable to
     such shares.

     4. Specific  Performance.  Affiliate agrees that irreparable  damages would
occur  in the  event  that  any of the  provisions  of this  Agreement  were not
performed in accordance with their specific  terms, or were otherwise  breached.
It is, accordingly,  agreed that Castelle shall be entitled to injunctive relief
to  prevent  breaches  of the  provisions  of  this  Agreement,  and to  enforce
specifically the terms and provisions hereof, in addition to any other remedy to
which Castelle may be entitled at law or in equity.

     5. Notices.  Any notice or other communication  required or permitted to be
delivered to Castelle or Affiliate  under this Agreement shall be in writing and
shall be deemed properly delivered,  given and received when delivered (by hand,
by registered  mail, by courier or express  delivery service or by facsimile) to
the address or  facsimile  telephone  number set forth  beneath the name of such
party  below (or to such other  address or  facsimile  telephone  number as such
party shall have specified in a written notice given to the other party):

                                       77



               if to Castelle:             CASTELLE

                                           3255-3 Scott Boulevard
                                           Santa Clara, California 95054
                                           Attn:  President
                                           Facsimile: (408) 654-4699

               if to Affiliate:            ______________________________

                                           ------------------------------

                                           ------------------------------

                                           ------------------------------

     6. Severability.  In the event that any provision of this Agreement, or the
application of any such provision to any person, entity or set of circumstances,
shall be  determined  to be  invalid,  unlawful,  void or  unenforceable  to any
extent,  the remainder of this Agreement,  and the application of such provision
to  persons,  entities  or  circumstances  other  than  those  as to which it is
determined to be invalid, unlawful, void or unenforceable, shall not be impaired
or otherwise  affected  and shall  continue to be valid and  enforceable  to the
fullest extent permitted by law.

     7. Governing Law. This Agreement shall be construed in accordance with, and
governed in all respects by, the laws of the State of California (without giving
effect to principles of conflicts of laws).

     8.  Waiver.  No failure on the part of Castelle or an Affiliate to exercise
any power, right, privilege or remedy under this Agreement,  and no delay on the
part of Castelle in exercising any power, right,  privilege or remedy under this
Agreement,  shall operate as a waiver of such power, right, privilege or remedy;
and no single or partial exercise of any such power, right,  privilege or remedy
shall  preclude  any other or further  exercise  thereof or of any other  power,
right, privilege or remedy. Neither Castelle nor an Affiliate shall be deemed to
have  waived any claim  arising  out of this  Agreement,  or any  power,  right,
privilege  or remedy  under this  Agreement,  unless  the waiver of such  claim,
power, right, privilege or remedy is expressly set forth in a written instrument
duly executed and delivered on behalf of Castelle; and any such waiver shall not
be applicable or have any effect except in the specific  instance in which it is
given.

     9. Captions.  The captions  contained in this Agreement are for convenience
of reference only,  shall not be deemed to be a part of this Agreement and shall
not be referred to in connection with the construction or interpretation of this
Agreement.

     10.  Further  Assurances.  Affiliate  shall  execute  and/or  cause  to  be
delivered to Castelle such  instruments  and other documents and shall take such
other actions as Castelle may  reasonably  request to effectuate  the intent and
purposes of this Agreement.

                                       78


     11. Entire Agreement.  This Agreement, the Reorganization Agreement and the
other  agreements  referred  to in the  Reorganization  Agreement  set forth the
entire  understanding  of Affiliate and Castelle  relating to the subject matter
hereof and thereof and supersede all prior agreements and understandings between
Affiliate and Castelle relating to the subject matter hereof and thereof.

     12. Amendments.  This Agreement may not be amended,  modified,  altered, or
supplemented  other  than by means of a written  instrument  duly  executed  and
delivered on behalf of Castelle and Affiliate.

     13.  Binding  Nature.  This  Agreement  will be binding upon  Affiliate and
Affiliate's   representatives,   executors,   administrators,   estate,   heirs,
successors  and  assigns,  and  shall  inure  to the  benefit  of  Castelle  and
Affiliates and their successors and assigns.

     14.  Attorneys'  Fees and  Expenses.  If any legal  action  or other  legal
proceeding  relating to the  enforcement  of any provision of this  Agreement is
brought against either Castelle or an Affiliate,  the prevailing  party shall be
entitled to recover  reasonable  attorneys'  fees, costs and  disbursements  (in
addition to any other relief to which the prevailing party may be entitled).

     15.  Termination.  This  Agreement  shall  terminate  and be of no force or
effect if the Reorganization  Agreement is validly terminated in accordance with
its terms without the Merger having occurred.  The representations,  warranties,
covenants and other  provisions  contained in this  Agreement  shall survive the
Merger.



CASTELLE:                                 AFFILIATE:




______________________________            _____________________________
        (Signature)                                   [name]



                                          Stock Beneficially Owned by Affiliate:
______________________________
        (Print Name)                      _____ shares of Common Stock

                                          _____ shares of Preferred Stock
______________________________
        (Print Title)

                                       79



                                    EXHIBIT A

                                   AFFILIATES



Tucha Limited

Newark Holding S.A.

Teodoro Ramos Gimenez

Ney Grant and Betsy Gray-Grant

Clovis Mattos

Curtis Powell

                                       80




                                   EXHIBIT C-2

                     PERSONS TO EXECUTE AFFILIATE AGREEMENTS


Ney Grant and Betsy Gray-Grant

Clovis Mattos

Teodoro Ramos Gimenez

Curtis Powell

Newark Holdings S.A.

Tucha Limited

                                       81




                                    EXHIBIT D

                       FORM OF TAX REPRESENTATION LETTERS

                                       82








____________, 1996





Cooley Godward Castro Huddleson & Tatum           Graham & James LLP
One Maritime Plaza, 20th Floor                    400 Capitol Mall, 24th Floor
San Francisco, California 94111                   Sacramento, California  95814


Re: Merger pursuant to that certain  Agreement and Plan of  Reorganization  (the
"Agreement")  dated  August 22, 1996 by and among  Castelle  ("Castelle"),  Ibex
Technology, Inc. ("Ibex") and the Signing Shareholders

Ladies and Gentlemen:

This letter is supplied to you in  connection  with your  rendering  of opinions
regarding  certain United States federal income tax  consequences of the Merger.
Unless  otherwise  indicated,  capitalized  terms not  defined  herein  have the
meanings set forth in the Agreement.

Representations

The  undersigned  officer of Ibex,  a California  corporation,  on behalf of the
management of Ibex, after  consulting with legal counsel and financial  auditors
regarding the meaning of and factual support for the following  representations,
hereby represents,  in connection with the proposed merger of Ibex, a California
corporation,  with  and into  Castelle  in a  statutory  merger  (the  "Merger")
pursuant to the Agreement and Exhibits thereto  including but not limited to the
Agreement of Merger, that as of the time this letter is executed,  the following
facts are true and will continue to be true as of the Effective Time and Closing
of the Merger and thereafter where relevant:



     1. Ibex's principal  reasons for  participating in the Merger are bona fide
business reasons.

     2. The total fair market  value of all  consideration  other than  Castelle
voting  common stock  received by Ibex  shareholders  in exchange for their Ibex
common and preferred stock in the Merger (including,  without  limitation,  cash
paid to Ibex shareholders perfecting dissenters' rights and cash paid in lieu of
fractional  shares) will be less than ten percent  (10%) of the  aggregate  fair
market value of Ibex common and preferred stock outstanding immediately prior to
the Merger.

     3. The liabilities of Ibex assumed by Castelle and the liabilities to which
the transferred assets of Ibex are subject were incurred by Ibex in the ordinary
course of its business.

                                       83


     4. The fair market value of Ibex's assets on the  Effective  Date which are
transferred  to Castelle will exceed the aggregate  liabilities of Ibex plus the
amount of liabilities,  if any, to which such assets are subject,  and the total
adjusted  basis of the  assets of Ibex  transferred  to  Castelle  will equal or
exceed  the sum of the  liabilities  assumed  by  Castelle,  plus the  amount of
liabilities, if any, to which the transferred assets are subject.

     5.  Ibex is not  and  will  not be on the  Effective  Date  an  "investment
company" within the meaning of ss.  368(a)(2)(F) of the Internal Revenue Code of
1986, as amended, (the "Code").

     6. Ibex has no  knowledge  of any plan or intention on the part of any Ibex
shareholder (a "Plan") to engage in a sale,  exchange,  transfer,  distribution,
pledge,  disposition or any other  transaction which would result in a direct or
indirect  disposition (a "Sale") of shares of Castelle voting common stock to be
issued to Ibex shareholders in the Merger,  which shares would have an aggregate
fair  market  value,  as of the  Effective  Date of the  Merger,  in  excess  of
fifty-percent (50%) of the aggregate fair market value, immediately prior to the
Merger,  of all  outstanding  shares of Ibex  common and  preferred  stock.  For
purposes of this  representation,  shares of Ibex common and preferred stock (or
the  portion  thereof)  (i) with  respect to which a Ibex  shareholder  receives
consideration in the Merger other than Castelle voting common stock  (including,
without limitation, cash received pursuant to the exercise of dissenters' rights
or paid in lieu of issuing  fractional shares) and/or (ii) with respect to which
a sale  occurs  during the  Pre-Merger  Period,  shall be  considered  shares of
outstanding Ibex common and preferred stock exchanged for Castelle voting common
stock in the Merger and then disposed of pursuant to a Plan.

     7. The  payment of cash by Castelle in lieu  issuing  fractional  shares of
Castelle  voting  common stock is solely for the purpose of avoiding the expense
and  inconvenience  to  Castelle  of  issuing  fractional  shares  and  does not
represent separately bargained for consideration.  The Castelle fractional share
interests to which each Ibex  shareholder  may be entitled in the Merger will be
aggregated  so that no Ibex  shareholder  will  receive  cash in an amount which
would  equal or  exceed,  in the  aggregate,  the  value of one  whole  share of
Castelle voting common stock.

     8.  Except  with  respect  to (1)  payments  of cash  to Ibex  shareholders
perfecting  dissenters'  rights,  and (2) payments of cash in lieu of fractional
shares of Castelle voting common and preferred stock, one hundred percent (100%)
of the Ibex common and  preferred  stock  outstanding  immediately  prior to the

                                       84


Merger will be exchanged solely for Castelle voting common stock.  Thus,  except
as set forth in the preceding  sentence,  Ibex intends that no  consideration be
paid or received (directly or indirectly,  actually or constructively)  for Ibex
common and preferred stock other than Castelle voting common stock.

     9. During the Pre-Merger  Period,  no indebtedness  or other  obligation of
Ibex has been or will be guaranteed by any shareholder of Ibex (or any person or
entity related to a shareholder of Ibex).

     10. On the  Effective  Date of the  Merger,  the fair  market  value of the
Castelle  voting  common  stock and other  consideration  received  by each Ibex
shareholder  will be  approximately  equal to the aggregate fair market value of
the Ibex common and preferred stock surrendered in exchange therefor.

     11. Ibex and the shareholders of Ibex will each pay separately its or their
own expenses in connection  with the Merger as  contemplated  by the  Agreement;
provided,  however,  that to the extent any expenses  relating to the Merger (or
the "plan of  reorganization"  within the meaning of Treas.  Reg. ss. 1.368-1(c)
with respect to the Merger) are funded  directly or  indirectly by a party other
than  the  incurring  party,   such  expenses  will  be  within  the  guidelines
established in Rev. Rul. 73-54, 1973-1 C.B. 187.

     12. There is no intercorporate  indebtedness  existing between Castelle and
Ibex that was issued,  acquired,  or will be settled at a  discount,  and to the
best knowledge of the management of Ibex, Castelle will assume no liabilities of
any Ibex shareholder in connection with the Merger.

     13.  The terms of the  Agreement  and all  other  agreements  entered  into
pursuant thereto are the product of arm's length negotiations.

     14. None of the compensation  payments  received by any shareholder of Ibex
will be separate consideration for, or allocable to, any of their shares of Ibex
common or preferred  stock.  None of the shares of Castelle  voting common stock
received  by any  shareholder  of Ibex will be  separate  consideration  for, or
allocable to, any employment agreement,  consulting agreement, any covenants not
to compete or otherwise for the  performance of services;  and the  compensation
paid to any shareholder of Ibex will be for services  actually rendered and will
be  commensurate  with amounts paid to third parties  bargaining at arm's length
for similar services.

     15. Ibex is authorized to make all of the representations set forth herein.

                                       85








                                     GENERAL

                       YOUR RELIANCE IN RENDERING OPINIONS
                          LIMITATIONS ON YOUR OPINIONS


     1. The undersigned recognize that (i) your opinions will be based on, among
other things,  the  representations  and  statements  set forth  herein,  in the
Agreement  (including  exhibits attached thereto),  and in the documents related
thereto,  and  (ii)  your  opinions  will be  subject  to  certain  limitations,
qualifications  and  assumptions  including  that the opinions may not be relied
upon if any such  representations or statements are not accurate in all material
respects.

     2. The  undersigned  recognize  that your opinions will not address any tax
consequences of the Merger or any action taken in connection therewith except as
expressly set forth in such opinions.

                                Very truly yours,

                                                  IBEX TECHNOLOGY, INC.
                                                  a California Corporation


                                                  By:

                                                  Title:

                                       86







                              ______________, 1996





Cooley Godward Castro Huddleson & Tatum         Graham & James LLP
One Maritime Plaza                              400 Capitol Mall, 24th Floor
20th Floor                                      Sacramento, California  95814
San Francisco, CA  94111


Re:      Merger  Transaction (the "Merger")  Pursuant to that certain  Agreement
         and Plan of Reorganization  (the "Agreement")  Dated  August 22,   1996
         by and among Castelle  ("Castelle"),  Ibex Technologies,  Inc. ("Ibex")
         and the Signing Shareholders

Ladies and Gentlemen:

     This letter is  supplied to you in  connection  with your  rendering  of an
opinion  regarding  certain United States federal income tax consequences of the
Merger.  Unless otherwise  indicated,  capitalized terms not defined herein have
the meanings set forth in the Agreement.

Representations

     The undersigned officer of Castelle, a California corporation, on behalf of
the management of Castelle,  after  consulting  with legal counsel and financial
auditors  regarding  the  meaning of and the factual  support for the  following
representations,  hereby  represents,  in connection with the proposed merger of
Ibex, a California  corporation,  with and into  Castelle in a statutory  merger
(the "Merger")  pursuant to the Agreement and Exhibits thereto including but not
limited to the Agreement of Merger,  with Castelle surviving the Merger, that as
of the time  this  letter is  executed,  the  following  facts are true and will
continue  to be true as of the  Effective  Time and  Closing  of the  Merger and
thereafter where relevant:

     1. Castelle's  principal  reasons for  participating in the Merger are bona
fide business reasons.

     2.  Castelle has no plan or intention to reacquire  any of its stock issued
in the Merger.

     3. Castelle has no plan or intention to sell or otherwise dispose of any of
the assets of Ibex acquired in the Merger,  except for dispositions  made in the

                                       87


ordinary  course of business or transfers  described in section  368(a)(2)(C) of
the Internal Revenue Code of 1986, as amended (the "Code").

     4. Following the Merger,  Castelle will continue  Ibex's  historic trade or
business  or use a  significant  portion of its  historic  business  assets in a
business.

     5. Castelle is not, and will not be on the Effective  Date, an  "investment
company" within the meaning of section 368(a)(2)(F) of the Code.

     6. No  shareholder  of Ibex is acting as agent for  Castelle in  connection
with the Merger or approval  thereof,  and Castelle  will not reimburse any Ibex
shareholder for Ibex common stock or preferred  stock such  shareholder may have
purchased or for other obligations such shareholder may have incurred.

     7. The payment of cash by Castelle in lieu of issuing  fractional shares of
Castelle  voting  common stock is solely for the purpose of avoiding the expense
and  inconvenience  to  Castelle  of  issuing  fractional  shares  and  does not
represent separately bargained for consideration.  The Castelle fractional share
interests to which each Ibex  shareholder  may be entitled in the Merger will be
aggregated  so that no Ibex  shareholder  will  receive  cash in an amount which
would  equal or  exceed,  in the  aggregate,  the  value of one  whole  share of
Castelle voting common stock.

     8.  Except  with  respect  to (1)  payments  of cash  to Ibex  shareholders
perfecting  dissenters' or appraisal  rights and (2) payments of cash in lieu of
fractional  shares of Castelle  voting  common  stock or  preferred  stock,  one
hundred percent (100%) of the Ibex common stock and preferred stock  outstanding
immediately  prior to the Merger will be exchanged  solely for  Castelle  voting
common  stock.  Thus,  except as set forth in the preceding  sentence,  Castelle
intends  that no  consideration  be paid or received  (directly  or  indirectly,
actually or constructively)  for Ibex common stock or preferred stock other than
Castelle voting common stock.

     9. The total fair market  value of all  consideration  other than  Castelle
voting  common stock  received by Ibex  shareholders  in exchange for their Ibex
common stock or preferred stock in the Merger  (including,  without  limitation,
cash paid to Ibex  shareholders  perfecting  dissenters' or appraisal rights and
cash paid in lieu of  fractional  shares) will be less than ten percent (10%) of
the  aggregate  fair  market  value of Ibex  common  stock and  preferred  stock
outstanding  immediately  prior to the  Merger.  In  addition,  the  total  cash

                                       88


consideration  that will be paid in the Merger to Ibex  shareholders  in lieu of
fractional  shares of Castelle  voting  common stock will not exceed one percent
(1%) of the total  consideration  that will be issued in the  Merger to the Ibex
shareholders  in exchange for their  shares of Ibex common  stock and  preferred
stock.

     10. On the  Effective  Date of the  Merger,  the fair  market  value of the
Castelle  voting  common  stock and other  consideration  received  by each Ibex
shareholder  will be  approximately  equal to the aggregate fair market value of
the Ibex common stock and preferred stock surrendered in exchange therefor.

     11.  Castelle will pay separately  its own expenses in connection  with the
Merger as contemplated by the Agreement;  provided,  however, that to the extent
any expenses relating to the Merger (or the "plan of reorganization"  within the
meaning of Treas.  Reg.  ss.  1.368-1(c)  with respect to the Merger) are funded
directly or indirectly by a party other than the incurring party,  such expenses
will be within the guidelines established in Rev. Rul. 73-54, 1973-1 C.B. 187.

     12. There is no intercorporate  indebtedness  existing between Castelle and
Ibex that was issued,  acquired, or will be settled at a discount,  and Castelle
will not assume any  liabilities of Ibex's  shareholders  in connection with the
Merger.

     13.  The terms of the  Agreement  and all  other  agreements  entered  into
pursuant thereto are the product of arm's-length negotiations.

     14.  None of the  compensation  payments  which  might be  received  by any
shareholder of Ibex will be separate  consideration for, or allocable to, any of
their  shares of Ibex common  stock or  preferred  stock;  none of the shares of
Castelle  voting common stock to be received by any  shareholder of Ibex will be
separate   consideration  for,  or  allocable  to,  any  employment   agreement,
consulting  agreement,  any  covenants  not to  compete  or  otherwise  for  the
performance  of  services;  and  the  compensation  which  might  be paid to any
shareholder  of  Ibex  will  be for  services  actually  rendered  and  will  be
commensurate  with amounts paid to third parties  bargaining at arm's length for
similar services.

     15.  Castelle  is  authorized  to make all the  representations  set  forth
herein.

                                     GENERAL

        Your Reliance In Rendering Opinions; Limitations On Your Opinions

     1. The  undersigned  recognizes  that (i) your  opinions  will be based on,
among other things, the  representations and statements set forth herein, in the
Agreement  (including  exhibits attached thereto),  and in the documents related

                                       89


thereto,  and  (ii)  your  opinions  will be  subject  to  certain  limitations,
qualification and assumptions including that the opinions may not be relied upon
if any such  representations  or  statements  are not  accurate in all  material
respects.

     2. The  undersigned  recognizes that your opinions will not address any tax
consequences of the Merger or any action taken in connection therewith except as
expressly set forth in such opinions.

                                Very truly yours,

                                                  CASTELLE,
                                                  a California corporation

                                                  By:

                                                  Title:


                                       90







                                    EXHIBIT E

                   FORM OF CONTINUITY OF INTEREST CERTIFICATE

                                       91




                       CONTINUITY OF INTEREST CERTIFICATE



     The  undersigned  is  aware  that  pursuant  to an  Agreement  and  Plan of
Reorganization,  dated as of August 22, 1996 (the  "Reorganization  Agreement"),
made  and  entered  into  by  and  among  CASTELLE,  a  California   corporation
("Castelle") and IBEX TECHNOLOGIES, INC., a California corporation ("Ibex"), and
certain  shareholders of Ibex, it is contemplated  that Ibex will merge with and
into  Castelle in a  transaction  (the  "Merger")  in which shares of the common
stock of Ibex ("Ibex Common Stock") and preferred  stock of Ibex ("Ibex Prefered
Stock") will be exchanged for shares of the common stock of Castelle  ("Castelle
Common Stock")

     1. The undersigned represents, warrants and certifies as follows:

     (a) The  undersigned  currently  is the owner of that  number  and class of
     shares of Ibex Common Stock and Ibex  Preferred  Stock set forth below (the
     "Shares")  and did not  acquire any of the Shares in  contemplation  of the
     Merger;

     (b) The  undersigned  has not engaged in a Sale (as  defined  below) of any
     shares of Ibex Common Stock or Ibex Preferred Stock in contemplation of the
     Merger;

     (c) The undersigned has, and will as of the Effective Date have, no plan or
     intention (a "Plan") to engage in a sale, exchange, transfer,  distribution
     (including  a  distribution  by a  partnership  to  its  partners  or  by a
     corporation to its stockholders), redemption or reduction in any way of the
     undersigned's  risk of  ownership  (by short sale or  otherwise),  or other
     disposition,  directly  or  indirectly  (such  actions  being  collectively
     referred to herein as a "Sale") of the shares of Castelle  Common  Stock to
     be received by the undersigned in the Merger. For purposes of the preceding
     sentence, shares of Ibex Common Stock or shares of Ibex Preferred Stock (or
     the portion thereof) (i) with respect to which the undersigned will receive
     consideration  in the Merger  other than  shares of Castelle  Common  Stock
     (including  cash to be  received in lieu of  fractional  shares of Castelle
     Common  Stock)  and/or  (ii) with  respect to which a Sale (A)  occurred in
     contemplation of the Merger or (B) will occur prior to the Merger, shall be
     considered  shares of Ibex Common Stock or shares of Ibex  Preferred  Stock
     exchanged  for  shares of  Castelle  Common  Stock in the  Merger  and then
     disposed of pursuant to a Plan;

     (d)  The  undersigned  has  no  Plan  to  exercise  dissenters'  rights  in
     connection with the Merger;

     (e) The undersigned is not aware of, or  participating  in, any Plan on the
     part of the  holders  of  shares  of Ibex  Common  Stock or  shares of Ibex
     Preferred  Stock to  engage in a Sale or Sales of the  shares  of  Castelle
     Common  Stock to be  received in the Merger  such that the  aggregate  fair
     market value,  as of the Effective  Time (as defined in the  Reorganization
     Agreement),  of shares  subject to such Sales would  exceed  fifty  percent
     (50%) of the aggregate fair market value of all shares of outstanding  Ibex
     Common Stock and Ibex Preferred Stock immediately prior to the Merger.  For
     purposes of the  preceding  sentence,  shares of Ibex Common  Stock (or the

                                       92


     portion  thereof) (i) with respect to which a shareholder  of Ibex receives
     consideration  in the Merger  other than  shares of Castelle  Common  Stock
     (including,  without limitation,  cash received pursuant to the exercise of
     dissenters'  rights or in lieu of a  fractional  share of  Castelle  Common
     Stock)  or (ii)  with  respect  to  which  a Sale  occurs  prior  to and in
     contemplation of the Merger, shall be considered shares of outstanding Ibex
     Common  Stock or Ibex  Preferred  Stock  exchanged  for shares of  Castelle
     Common Stock in the Merger and then disposed of pursuant to a Plan;

     (f) The  undersigned  waives  any and all  rights to seek  damages or other
     relief from Castelle or Ibex as a result of any losses incurred as a result
     of the  inaccuracy  of any or all of the  representations  set forth in the
     certificate  dated  August  __,  1996 from Ibex to  Cooley  Godward  Castro
     Huddleson  & Tatum and Graham & James  LLP,  provided  pursuant  to Section
     5.8(b) of the Reorganization Agreement.

     (g) Except to the extent written  notification  to the contrary is received
     by Ibex from the undersigned prior to the Merger, the  representations  and
     warranties and certifications contained herein shall be true and correct at
     all times from the date hereof through the date on which the Merger occurs.

     2. The undersigned  has consulted with such legal and financial  counsel as
the undersigned has deemed  appropriate in connection with the execution of this
Certificate.

     3. The undersigned  understands  that Castelle,  Ibex, and their respective
shareholders,  as well as legal counsel to Castelle and Ibex (in connection with
rendering of their  opinions that the Merger will be a  "reorganization"  within
the meaning of Section 368(a) of the Internal  Revenue Code of 1986, as amended)
will be relying on (a) the truth and accuracy of the  representations  contained
herein  and (b) the  undersigned's  performance  of the  obligations  set  forth
herein.

     IN WITNESS  WHEREOF,  the  undersigned  has executed  this  Certificate  on
_____________________, 1996.

                                   Signature:

                                   Name:

                                   Address:





Number of Shares of Ibex Common Stock Beneficially Owned:

Number of Shares of Ibex Preferred Stock Beneficially Owned:

                                       93




                                    EXHIBIT F

                                 PERSONS TO SIGN
                    EMPLOYMENT AND NONCOMPETITION AGREEMENTS


Ney Grant

Curtis Powell

Clovis Mattos

Bryan Roe (no noncompetition agreement)

Fabio Matsui (no noncompetition agreement)

                                       94




                                    EXHIBIT G

                          FORM OF EMPLOYMENT AGREEMENT

                                       95




                              EMPLOYMENT AGREEMENT



        THIS  EMPLOYMENT  AGREEMENT  ("Agreement")  is being  entered into as of
August __, 1996 (the  "Closing  Date") by and  between  CASTELLE,  a  California
corporation (the "Corporation"), and ____________________ ("Employee").

                                    RECITALS

     A. Pursuant to an Agreement and Plan of Merger and Reorganization, dated as
of August 22, 1996, by and among the  Corporation,  Ibex  Technologies,  Inc., a
California  corporation  ("Ibex"),  and certain shareholders of Ibex, as amended
(the  "Reorganization  Agreement"),  Ibex is merging into the Corporation on the
Closing Date (the "Merger").  As a result of the Merger,  Ibex  shareholders are
receiving shares of Common Stock of the Corporation in exchange for their shares
of stock of Ibex.

     B.  Employee was a  shareholder  of Ibex prior to the Merger,  and has been
serving as an employee of Ibex.

     C. The  Corporation  has  required,  as a  condition  to  consummating  the
transactions contemplated by the Reorganization Agreement, that Employee execute
and deliver this Agreement.

     D.  Contemporaneously  with the execution  and delivery of this  Agreement,
Employee  is  executing  and  delivering  to the  Corporation  a  Noncompetition
Agreement   of  even  date   herewith.   The   Reorganization   Agreement,   the
Noncompetition  Agreement and the Proprietary  Information  Agreement previously
executed  by  Employee in favor of Ibex are  referred  to  collectively  in this
Agreement as the "Other Agreements."

                                    AGREEMENT

     In  order  to  induce  the  Corporation  to  consummate  the   transactions
contemplated by the Reorganization  Agreement,  and in further  consideration of
the mutual  covenants  and  agreements  contained  herein,  the parties agree as
follows:

1. EMPLOYMENT

     1.1 Term; Duties.

     (a) Term.  Subject to Section  1.7  below,  Employee  agrees to serve as an
     employee of the  Corporation  during the period  commencing  on the Closing
     Date  and  ending  on the  date  two  years  from  the  Closing  Date  (the
     "Employment Term").

                                       96


     (b)  Duties.  During the  Employment  Term,  Employee  shall  serve in such
     capacity as the  Corporation's  Chairman may specify from time to time, and
     shall  have  such  responsibilities  as  may  be  assigned  to  him  by the
     Corporation's Chairman. Employee agrees to serve the Corporation faithfully
     and to the best of his  ability,  and to  devote  substantially  all of his
     working  time,  attention  and efforts  during the  Employment  Term to the
     business and affairs of the Corporation.  Employee  represents and warrants
     to the Corporation that he is under no contractual commitments inconsistent
     with his obligations set forth in this Agreement.

     1.2 Salary.  In consideration of all services to be rendered by Employee to
the  Corporation  during  the  Employment  Term,  the  Corporation  shall pay to
Employee  a salary of  $__________  per  annum,  payable  at such times as other
salaried  employees of the  Corporation  receive their regular salary  payments.
Employee's  salary may be  increased  by the  Corporation  as a result of salary
reviews to be conducted by Castelle's Chief Executive Officer periodically.  The
Corporation  shall be entitled to withhold  from the salary  payments  otherwise
required to be made to Employee such amounts as the  Corporation may be required
to withhold under applicable tax laws and other applicable legal requirements.

     1.3 Stay-On Bonus  Payments.  Subject to Section  1.7(b),  the  Corporation
shall pay to Employee, as a stay-on bonus,  $__________ per month on each of the
first 12 monthly anniversaries of the Closing Date.

     1.4 Other Benefits.  The Corporation shall provide to Employee,  during the
Employment  Term,  the  same  benefits  that  the  Corporation  makes  generally
available to all of its other employees during the Employment  Term,  subject to
Employee's  satisfaction  of the respective  eligibility  requirements  for such
benefits.

     1.5 Other Compensation  Matters.  Employee  acknowledges and agrees that he
shall not be entitled to receive from the  Corporation,  or from Castelle or any
other affiliate of the Corporation,  any salary,  bonus or other compensation or
benefit of any nature (whether  relating to any period prior to the Closing Date
or relating to any period after the Closing  Date) except as expressly  provided
in the  Other  Agreements  or in  Sections  1.2,  1.3  and 1.4  above.  Employee
represents and warrants to the Corporation that he is not aware of any claims or
rights  against the  Corporation  arising  directly or indirectly  from his past
employment with the Corporation, and Employee hereby releases and discharges the
Corporation  and its  affiliates  from all  claims,  rights,  causes of  action,
demands and obligations  relating to or arising  directly or indirectly from his
past employment with the Corporation.

     1.6  Expenses.  Employee  shall  be  entitled  to  reimbursement  from  the
Corporation for reasonable  out-of-pocket  business expenses reasonably incurred
by Employee during the Employment  Term in the performance of Employee's  duties
under this  Agreement;  provided,  however,  that the  Corporation  shall not be
required to  reimburse  Employee  for any such  expenses  unless:  (a)  Employee
presents  vouchers and receipts  indicating in reasonable  detail the amount and
business purpose of each of such expenses;  and (b) Employee  otherwise complies
with the Corporation's  reimbursement policies established from time to time and
in effect during the Employment Term.

                                       97


     1.7 Termination.

     (a)  Either  the  Corporation  or the  Employee  shall  have  the  right to
     terminate this Agreement,  with or without Cause (as defined in Section 1.8
     below), at any time during the Employment Term by delivering written notice
     of termination to the other.  Upon the termination of this Agreement during
     the Employment  Term,  Employee's  employment  with the  Corporation  shall
     terminate and, except as provided in Section 1.7(b) below,  the Corporation
     shall have no further monetary obligation or other obligation of any nature
     to Employee  under this  Agreement or with respect to his employment or the
     termination of his employment.

     (b) If (i) the  Corporation  terminates  this  Agreement  without Cause (as
     defined in Section 1.8 below)  during the  Employment  Term,  (ii) Employee
     satisfies  all of  his  obligations  relating  to  the  termination  of his
     employment  under this Agreement  (including his obligations  under Section
     3.2 below),  and (iii) Employee  executes and delivers to the Corporation a
     general  release of liability  (satisfactory  in form and  substance to the
     Corporation) in favor of the Corporation, then so long as Employee does not
     breach  Section  2 below or any of the  material  provisions  of the  Other
     Agreements,  Employee  shall be  entitled to continue to receive the salary
     specified in Section 1.2 above for the remainder of the Employment Term and
     the stay-on bonus payments specified in Section 1.3.

     (c) The  termination  of this  Agreement  pursuant  to this  Section 1.7 or
     otherwise shall not limit or otherwise affect any of Employee's obligations
     under Section 2 or Section 3.2 below or under any of the Other  Agreements,
     all of which shall remain in full force and effect.

     1.8 Definition of "Cause." Employee's employment with the Corporation shall
be deemed to have been  terminated for "Cause" if such  employment is terminated
following:  (a) any  intentional  misconduct,  fraud or bad faith on the part of
Employee in the performance of his duties as an employee of the Corporation; (b)
the  conviction  of Employee of, or the entry by Employee of a plea of guilty or
no contest to, any felony;  (c) the breach by Employee of any material provision
in any of the Other Agreements; (d) the continued failure of Employee to perform
any  reasonable  duties  assigned to him, if such breach or failure is not fully
cured by  Employee  within ten days  after he  receives  written  notice of such
failure;  or (e) the inability of Employee to perform any of his material duties
as a result of illness or injury,  if Employee  remains  unable to perform  such
duties for a total of ten consecutive weeks.

2. CONFIDENTIAL INFORMATION

     2.1 Proprietary Information Agreement.  Employee acknowledges that Employee
has previously executed a Proprietary Information Agreement in favor of Ibex and
agrees to continue to abide by the  provisions of such agreement both during and
after the Employment Term as provided therein.

                                       98


     2.2  Obligation  to  Keep   Confidential.   Employee  agrees  to  keep  all
Confidential  Information  (as  defined  in  Section  2.3  below)  strictly  and
permanently confidential and, accordingly,  agrees that he shall not at any time
(whether during or after the Employment Term) directly or indirectly use for any
purpose,  or disclose  or permit to be  disclosed  to any person or entity,  any
Confidential   Information.   Employee   acknowledges   that  the   Confidential
Information  constitutes  unique and valuable assets of Ibex and the Corporation
acquired  at great time and  expense by Ibex and the  Corporation,  and that any
disclosure  or other use of such  Confidential  Information,  other than for the
sole  benefit of Ibex and the  Corporation,  would be  wrongful  and would cause
irreparable harm to the Corporation.

     2.3  Definition  of  "Confidential  Information."  The  term  "Confidential
Information"  means any non-public  information  (whether or not in written form
and whether or not expressly  designated as confidential)  relating  directly or
indirectly  to the  Corporation,  Ibex  or any of  the  Corporation's  or  Ibex'
subsidiaries  or other  affiliates  or  relating  to the  business,  operations,
financial affairs,  performance,  assets,  investments,  technology,  processes,
products, contracts, customers, licensees,  sublicensees,  suppliers, personnel,
plans or prospects of the  Corporation  or Ibex or any of the  Corporation's  or
Ibex subsidiaries or other affiliates, including any such information consisting
of or otherwise  relating  directly or  indirectly to trade  secrets,  know-how,
technology,  designs, drawings,  processes,  license or sublicense arrangements,
formulae,  proposals,  customer lists or  preferences,  pricing lists,  referral
sources,  marketing or sales techniques or plans,  operations  manuals,  service
manuals, financial information,  projections, lists of suppliers or distributors
or sources of supply; provided,  however, that "Confidential  Information" shall
not be deemed to include information which, at the time of initial disclosure to
Employee,  is part  of,  or  without  violation  of this  Agreement  or fault of
Employee becomes part of, the public knowledge or literature.

3. MISCELLANEOUS PROVISIONS

     3.1 Other  Agreements.  Nothing in this Agreement shall limit Employee's or
the  Corporation's  obligations  or the rights and  remedies  of Employee or the
Corporation  under  the  Other  Agreements,  and  nothing  in any  of the  Other
Agreements shall limit Employee's or the Corporation's obligations or the rights
and remedies of the Employee or the Corporation under this Agreement.

     3.2 Surrender of Records and  Property.  At such time as Employee no longer
serves as an employee of the Corporation, Employee shall deliver promptly to the
Corporation (a) all records,  manuals, books, blank forms,  documents,  letters,
memoranda,  notes,  notebooks,  reports,  data,  tables,  calculations or copies
thereof in his  possession  or under his control  which are the  property of the
Corporation,  and (b) all other  property and  Confidential  Information  of the
Corporation  or Castelle in his  possession or under his control,  including all
documents  which contain any  Confidential  Information  of the  Corporation  or
Castelle.

                                       99


     3.3 Notices. Any notice or other communication  required or permitted to be
delivered to either party under this Agreement  shall be in writing and shall be
deemed  properly  delivered,  given and received  when  delivered  (by hand,  by
registered  mail, by courier or express delivery service or by facsimile) to the
address or facsimile  telephone  number set forth beneath the name of such party
below (or to such other  address  or  facsimile  telephone  number as such party
shall have specified in a written notice given to the other party hereto):

               If to the Corporation:             CASTELLE

                                                  3255-3 Scott Boulevard
                                                  Santa Clara, CA  95054
                                                  Attention:    President
                                                  Facsimile:    (408) 654-4699

               If to Employee:





     3.4 Severability. In the event that any provision of this Agreement, or the
application of any such provision to any person, entity or set of circumstances,
shall be  determined  to be  invalid,  unlawful,  void or  unenforceable  to any
extent,  the remainder of this Agreement,  and the application of such provision
to  persons,  entities  or  circumstances  other  than  those  as to which it is
determined to be invalid, unlawful, void or unenforceable, shall not be impaired
or otherwise  affected  and shall  continue to be valid and  enforceable  to the
fullest extent permitted by law.

     3.5 Governing  Law. This Agreement  shall be construed in accordance  with,
and governed in all respects  by, the laws of the State of  California  (without
giving effect to principles of conflicts of laws).

     3.6 Waiver.  No failure on the part of either  party to exercise any power,
right,  privilege  or remedy under this  Agreement,  and no delay on the part of
either  party in  exercising  any power,  right,  privilege or remedy under this
Agreement,  shall operate as a waiver of such power, right, privilege or remedy;
and no single or partial exercise of any such power, right,  privilege or remedy
shall  preclude  any other or further  exercise  thereof or of any other  power,
right,  privilege  or remedy.  Neither  party shall be deemed to have waived any
claim arising out of this Agreement,  or any power,  right,  privilege or remedy
under this Agreement,  unless the waiver of such claim, power, right,  privilege
or remedy is  expressly  set forth in a written  instrument  duly  executed  and
delivered on behalf of such party;  and any such waiver shall not be  applicable
or have any effect except in the specific instance in which it is given.

     3.7 Captions.  The captions contained in this Agreement are for convenience
of reference only,  shall not be deemed to be a part of this Agreement and shall
not be referred to in connection with the construction or interpretation of this
Agreement.

                                      100


     3.8 Counterparts.  This Agreement may be executed in several  counterparts,
each of  which  shall  constitute  an  original  and all of  which,  when  taken
together, shall constitute one agreement.

     3.9 Further Assurances.  Each party hereto shall execute and/or cause to be
delivered to the other party hereto such  instruments  and other  documents  and
shall take such other  actions as such  other  party may  reasonably  request to
effectuate the intent and purposes of this Agreement.

     3.10 Entire  Agreement.  This Agreement and the Other  Agreements set forth
the entire  understanding  of the parties  relating to the subject matter hereof
and thereof and supersede all prior  agreements and  understandings  between the
parties relating to the subject matter hereof and thereof.

     3.11 Amendments.  This Agreement may not be amended,  modified,  altered or
supplemented  other  than by means of a written  instrument  duly  executed  and
delivered on behalf of the Corporation and Employee.

     3.12 Assignment.  This Agreement and all rights and obligations of Employee
hereunder  are  personal to Employee and may not be  transferred  or assigned by
Employee at any time.  The  Corporation  may, with  Employee's  written  consent
(which consent shall not be unreasonably withheld), assign its rights under this
Agreement to any entity that assumes the Corporation's  obligations hereunder in
connection  with any sale or  transfer  of all or a  substantial  portion of the
Corporation's assets to such entity.

     3.13 Binding Nature.  Subject to Section 3.12 above, this Agreement will be
binding upon and inure to the benefit of the  Corporation and its successors and
assigns and Employee and his representatives, executors, administrators, estate,
heirs, successors and assigns.

     3.14  Attorneys'  Fees and  Expenses.  If any legal  action or other  legal
proceeding  relating to the  enforcement  of any provision of this  Agreement is
brought against either party hereto,  the prevailing  party shall be entitled to
recover reasonable  attorneys' fees, costs and disbursements (in addition to any
other relief to which the prevailing party may be entitled).

                                      101




     IN WITNESS  WHEREOF,  the parties  hereto have caused this  Agreement to be
executed and delivered as of the date first above written.

                                  CASTELLE

                                  By:

                                  Its:




                                      102





                                    EXHIBIT H

                        FORM OF NONCOMPETITION AGREEMENT
                            NONCOMPETITION AGREEMENT

                                      103



                            NONCOMPETITION AGREEMENT


     THIS NONCOMPETITION AGREEMENT ("Agreement") is being executed and delivered
as of August __, 1996 (the "Closing Date"), by _____________  ("Shareholder") in
favor of and for the benefit of CASTELLE, a California corporation ("Company").

                                    RECITALS

     A. As an employee  and major  shareholder  of Ibex  Technologies,  Inc.,  a
California corporation ("Ibex"), Shareholder has obtained extensive and valuable
knowledge  and   information   concerning   the  business  of  Ibex   (including
confidential information relating to Ibex and its operations, assets, contracts,
customers, personnel, plans and prospects).

     B. Pursuant to an Agreement and Plan of Merger and Reorganization  dated as
of August 22, 1996,  by and among the  Company,  Ibex,  Shareholder  and certain
other  shareholders  of the Company (the  "Reorganization  Agreement"),  Ibex is
merging into the Company on the Closing Date (the "Merger").  In connection with
the Merger,  Shareholder and the Company's other shareholders are exchanging all
of their shares of stock of Ibex for shares of Common Stock of the Company.

     C.  Concurrently  with this  Agreement,  Shareholder  has  entered  into an
Employment  Agreement  with  Company  with a term of two years (the  "Employment
Agreement").

     D. In connection with the Merger (and as a condition to the consummation of
the  Merger),  and to more fully  secure unto the  Company  the  benefits of the
Merger,  the Company has required that Shareholder enter into this Agreement and
Shareholder  is entering  into this  Agreement in order to induce the Company to
consummate the Merger.

     E. The Company has conducted and is conducting  its business on a worldwide
basis.

                                    AGREEMENT

     In order to induce the Company to consummate the transactions  contemplated
by the  Reorganization  Agreement,  and in  consideration  of the  issuance  and
delivery to Shareholder of shares of Common Stock of the Company pursuant to the
Reorganization Agreement, Shareholder agrees as follows:

     1.  Acknowledgments  by  Shareholder.  Shareholder  acknowledges  that  the
promises  and  restrictive  covenants  he is  providing  in this  Agreement  are
reasonable  and  necessary  for  the  Company's  protection  of  its  legitimate
interests in its acquisition of Ibex pursuant to the  Reorganization  Agreement,
including  but not limited to Ibex's  goodwill.  Shareholder  acknowledges  that
Shareholder  is  exchanging  all of  Shareholder's  shares  of stock of Ibex for
shares of Common Stock of the Company in the Merger.

                                      104


     2.  Noncompetition.  During the period  commencing  on the Closing Date and
continuing  until  the date  __________  (__)  years  after the  termination  of
Employee's  employment with the Company (the "Noncompete  Period"),  Shareholder
shall  not,  directly  or  indirectly,  provide  any  service  (as an  employee,
consultant or otherwise),  support  (including  financial  support),  product or
technology  to any  person or  entity,  if such  service,  support,  product  or
technology involves or relates to, in any material respect, (A) the provision of
"information  on  demand"  products,  including  but  not  limited  to  products
delivering  information via facsimile,  voice, video or any Internet mechanisms,
(B)  "electronic  commerce," (C) the use of the Internet for effecting  economic
transactions,  (D) the provision of  information  or products over the Internet,
(E) the design,  development,  coding or  creation  of software  for use with or
otherwise  involving  the  Internet  including,  but not limited to, the design,
development  or coding of software for the purpose of  gathering,  collecting or
analyzing  market  data,  customer  data or web  site  visits  (hits)  over  the
Internet, or (F) the design,  development or coding of management software tools
utilized with  "information on demand" products or to enhance the  functionality
of  network  facsimile  products  (each,  a  "Restricted  Business");  provided,
however, that nothing in this Section 2 shall prevent Shareholder from providing
services, support, products or technology to any person or entity while employed
by the Company,  so long as Shareholder  is providing  such  services,  support,
products and technology  solely in Shareholder's  capacity as, and solely in the
course of discharging  Shareholder's duties and responsibilities as, an employee
of the Company.

     3.  Nonsolicitation.  Shareholder further agrees that during the Noncompete
Period, Shareholder will not:

     (a)  directly  or  indirectly,  personally  or through  others,  encourage,
     induce,  attempt to induce, solicit or attempt to solicit (on Shareholder's
     own behalf or on behalf of any other  person or entity) any employee of the
     Company,  or  any  of  the  Company's  subsidiaries  to  leave  his  or her
     employment with the Company, or any or of the Company's subsidiaries;

     (b)  employ,  or permit any entity  over which  Shareholder  exercises  any
     control,  to employ such employee who has  terminated his or her employment
     with the Company or any of the Company's subsidiaries during the Noncompete
     Period; or

     (c)  directly  or  indirectly,  personally  or  through  others,  approach,
     contact,  solicit,  advise  or do (or  attempt  to do)  business  with,  or
     otherwise  interfere  with the  relationship  of the  Company or any of the
     Company's  subsidiaries  with,  any  person  or  entity  who is,  was or is
     reasonably anticipated to become a customer or client of the Company or any
     of the Company's subsidiaries with respect to any Restricted Business.

     4. Consideration.  As consideration for this Noncompetition  Agreement, the
     Company shall pay  Shareholder  $_______.  Such  payments  shall be made to

                                      105


     Shareholder in three (3) $____  installments with the first installment due
     on the date of this Agreement and the second and third  installments due on
     the first and second monthly anniversaries of the date of this Agreement.

     5.  Termination.  Shareholder's  obligations  under  Sections  2 and 3, and
     Company's  obligations  under  Section 4 shall  terminate if  Shareholder's
     employment with Company pursuant to the Employment  Agreement is terminated
     without Cause (as such term is defined in the Employment Agreement).

     6.  Independence of Obligations.  The covenants of Shareholder set forth in
     this Agreement  shall be construed as independent of any other agreement or
     arrangement  between  Shareholder,  on the one hand, and the Company on the
     other. The existence of any claim or cause of action by Shareholder against
     the  Company  shall not  constitute  a defense to the  enforcement  of such
     covenants against Shareholder.

     7. Specific Performance. Shareholder agrees that in the event of any breach
     or threatened  breach by Shareholder  of any covenant,  obligation or other
     provision  contained in this  Agreement,  the Company shall be entitled (in
     addition to any other remedy that may be available to them) to (a) a decree
     or order of specific  performance or mandamus to enforce the observance and
     performance of such  covenant,  obligation or other  provision,  and (b) an
     injunction restraining such breach or threatened breach.

     8.  Non-Exclusivity.  The rights and remedies of the Company  hereunder are
     not  exclusive  of or limited  by any other  rights or  remedies  which the
     Company may have, whether at law, in equity, by contract or otherwise,  all
     of which shall be cumulative (and not  alternative).  Without  limiting the
     generality  of the  foregoing,  the  rights  and  remedies  of the  Company
     hereunder,  and the obligations  and liabilities of Shareholder  hereunder,
     are in addition  to their  respective  rights,  remedies,  obligations  and
     liabilities under the law of unfair competition,  misappropriation of trade
     secrets and the like. This Agreement does not limit, and is not limited by,
     the terms of the Employment  Agreement or the terms of any other  agreement
     between Shareholder and the Company or any affiliate of the Company.

     9. Notices.  Any notice or other communication  required or permitted to be
     delivered to Shareholder  or the Company under this  Agreement  shall be in
     writing and shall be deemed  properly  delivered,  given and received  when
     delivered  (by hand, by  registered  mail,  by courier or express  delivery
     service or by facsimile) to the address or facsimile  telephone  number set
     forth  beneath  the name of such party  below (or to such other  address or
     facsimile  telephone number as such party shall have specified in a written
     notice given to the other party hereto):

               If to the Company:   CASTELLE

                                    3255-3 Scott Boulevard
                                    Santa Clara, CA  95054
                                    Attention:    President
                                    Facsimile:    (408) 654-4699

                                      106


               If to Shareholder:





     10.  Severability.  If any  provision of this  Agreement or any part of any
such provision is held under any circumstances to be invalid or unenforceable in
any jurisdiction, then (a) such provision or part thereof shall, with respect to
such  circumstances  and in such  jurisdiction,  be deemed amended to conform to
applicable  laws so as to be  valid  and  enforceable  to the  fullest  possible
extent, (b) the invalidity or unenforceability of such provision or part thereof
under such  circumstances and in such jurisdiction shall not affect the validity
or   enforceability   of  such   provision  or  part  thereof  under  any  other
circumstances  or  in  any  other  jurisdiction,  and  (c)  such  invalidity  of
enforceability  of such  provision or part thereof shall not affect the validity
or  enforceability  of the  remainder  of  such  provision  or the  validity  or
enforceability of any other provision of this Agreement.  Each provision of this
Agreement is separable from every other  provision of this  Agreement,  and each
part of each  provision of this  Agreement is separable from every other part of
such provision.

     11.  Governing Law. This Agreement  shall be construed in accordance  with,
and governed in all respects  by, the laws of the State of  California  (without
giving effect to principles of conflicts of laws).

     12.  Waiver.  No failure on the part of the Company to exercise  any power,
right, privilege or remedy under this Agreement, and no delay on the part of the
Company  in  exercising  any  power,  right,  privilege  or  remedy  under  this
Agreement,  shall operate as a waiver of such power, right, privilege or remedy;
and no single or partial exercise of any such power, right,  privilege or remedy
shall  preclude  any other or further  exercise  thereof or of any other  power,
right,  privilege or remedy.  The Company shall not be deemed to have waived any
claim arising out of this Agreement,  or any power,  right,  privilege or remedy
under this Agreement,  unless the waiver of such claim, power, right,  privilege
or remedy is  expressly  set forth in a written  instrument  duly  executed  and
delivered on behalf of such party;  and any such waiver shall not be  applicable
or have any effect except in the specific instance in which it is given.

     13. Captions.  The captions contained in this Agreement are for convenience
of reference only,  shall not be deemed to be a part of this Agreement and shall
not be referred to in connection with the construction or interpretation of this
Agreement.

     14.  Further  Assurances.  Shareholder  shall  execute  and/or  cause to be
delivered to the Company such  instruments  and other  documents  and shall take
such other actions as Company may  reasonably  request to effectuate  the intent
and purposes of this Agreement.

                                      107


     15. Entire Agreement.  This Agreement and the Employment Agreement (and the
other agreements  referred to in the Employment  Agreement) set forth the entire
understanding  of  Shareholder  and the Company  relating to the subject  matter
hereof and thereof and supersede all prior agreements and understandings between
any of such parties relating to the subject matter hereof and thereof.

     16. Amendments.  This Agreement may not be amended,  modified,  altered, or
supplemented  other  than by means of a written  instrument  duly  executed  and
delivered on behalf of the Company and Shareholder.

     17. Assignment.  This Agreement and all obligations  hereunder are personal
to  Shareholder  and may not be  transferred  or assigned by  Shareholder at any
time. The Company may, with  Shareholder's  written consent (which consent shall
not be  unreasonably  withheld),  assign its rights under this  Agreement to any
entity in connection  with any sale or transfer of all or a substantial  portion
of the Company's assets to such entity.

     18. Binding  Nature.  Subject to Section 17, this Agreement will be binding
upon Shareholder and Shareholder's representatives,  executors,  administrators,
estate,  heirs,  successors  and  assigns,  and will inure to the benefit of the
Company and its respective successors and assigns.

     19.  Attorneys'  Fees and  Expenses.  If any legal  action  or other  legal
proceeding  relating to the  enforcement  of any provision of this  Agreement is
brought against  Shareholder,  the prevailing party shall be entitled to recover
reasonable  attorneys' fees, costs and  disbursements  (in addition to any other
relief to which the prevailing party may be entitled).

                                      108




     IN WITNESS  WHEREOF,  the undersigned has executed this Agreement as of the
date first above written.


                                      109




                                    EXHIBIT I

                   FORM OF LEGAL OPINION OF GRAHAM & JAMES LLP

                                      110




                       [GRAHAM & JAMES LLP OPINION LETTER]

                       
Castelle
3255-3 Scott Boulevard
Santa Clara, CA  95054

Ladies and Gentlemen:

We have  acted as  legal  counsel  for Ibex  Technologies,  Inc.,  a  California
corporation (the  "Company"),  in connection with the merger of the Company with
and  into  Castelle,  a  California  corporation  ("Castelle")  pursuant  to  an
Agreement  and  Plan  of  Reorganization  dated  as  of  August  22,  1996  (the
"Reorganization  Agreement") by and among the Company,  Castelle and the Signing
Shareholders listed on Exhibits A-1 and A-2 of the Agreement (the "Merger").  We
are rendering this opinion  pursuant to Section 6.6(i) of the Agreement.  Except
as otherwise defined herein,  capitalized terms used but not defined herein have
the respective meanings given to them in the Agreement.

In  rendering  this  opinions  expressed  below,  we  have  examined  originals,
certified  copies or copies  otherwise  identified to us as being true copies of
the originals of the following documents:

     (a) The Agreement.

     (b) The Merger Agreement.

Items (a) and (b) are hereafter collectively referred to as the "Agreements".

We  have  also  considered  such  questions  of  law  and  examined  such  other
instruments, records, certificates, opinions, memoranda and documents as we have
deemed  necessary or advisable for the purpose of preparing this opinion letter.
As to questions of fact material to this opinion letter, we have relied upon the
certificates  of  officers  of  the  Company.  We  have  undertaken  no  further
investigation  in  connection  with this  opinion  letter  except  for only such
factual inquiries as we deemed  appropriate with respect to the facts underlying
such certificates and the Agreements.

                                      111




Castelle
______________, 1996
 



In rendering this opinion, we have assumed the following:

     (i) The  representations  and  warranties in the  Agreements  and any other
     certificates,  instruments  or agreements  executed in connection  with the
     Agreements or delivered to us are true, correct and not misleading;

     (ii) The  signatures on all original  documents  examined by us are genuine
     and all copies of such documents submitted to us are genuine;

     (iii) The due authorization, execution and delivery of all documents (other
     than  the  Company  where  authorization,  execution  and  delivery  are  a
     prerequisite to the effectiveness thereof);

     (iv) All  individuals  executing  and  delivering  documents  had the legal
     capacity to so execute and deliver;

     (v) Each party to the Agreements, other than the Company is duly organized,
     validly   existing  and  in  good  standing  under  its   jurisdiction   of
     organization and is in good standing as a foreign  corporation in each such
     jurisdiction  in which the  conduct of its  business  or its  ownership  or
     leasing  of  property  currently  requires  that it  qualify  as a  foreign
     corporation,  with the corporate or other  organizational  power to perform
     its  obligations  under the  Agreements  to which it is a party,  each such
     party has complied with any applicable  requirement to file tax returns and
     pay taxes in each  jurisdiction in which it is required to do so, each such
     party has validly authorized, executed and delivered each of the Agreements
     to which it is a party and the Agreements  constitute the valid and binding
     obligations  of each such  party,  enforceable  against  each such party in
     accordance with their terms;

     (vi) The  factual  matters set forth in the  Agreements  are  accurate  and
     complete  in all  material  respects  and all  certificates  and all  other
     written  representations  as to factual matters  delivered or made to us by
     officers  of the  Company or the  Signing  Shareholders  are  accurate  and
     complete in all material respects;

     (vii) There are no agreements, written or oral, among any of the parties to
     any of the Agreements that modify,  waive, amend or affect the terms of any
     of the Agreements;

     (viii) Neither the execution of the Agreements nor the  consummation of the
     transactions  provided for therein  contravenes  any  applicable law of any
     jurisdiction, other than California law or federal law.


                                       112




Castelle
______________, 1996
 


     The opinions hereinafter  expressed are subject to the following additional
qualifications:

     (a) The  attorneys in our firm who have  prepared this opinion are admitted
     to practice law only in the States of California, and we express no opinion
     herein  concerning  any law other than the law of the States of  California
     and the federal law of the United States.

     (b) To the  extent any  opinion  is  rendered  herein  with  respect to the
     enforceability of any agreement: (1) we express no opinion as to the effect
     on  such   enforceability  of  applicable   federal  or  state  bankruptcy,
     insolvency,  reorganization,  moratorium  or other  similar laws  generally
     affecting  relief of debtors or the enforcement of the rights of creditors;
     (2) we express no opinion as to the effect on such  enforceability  of laws
     governing specific performance,  injunctive relief, fraudulent sales and/or
     conveyances,   preferences   or   other   equitable   remedies;   (3)   the
     enforceability  of  obligations  in the  Agreements  is  subject to general
     principles  of  equity   regardless  of  whether  such   enforceability  is
     considered  in a  proceeding  in equity or law, and a court  applying  such
     principles  may  refuse to  enforce,  or may limit  the  application  of, a
     contract or any clause  thereof;  and (4)  enforcement  of  indemnification
     provisions contained in the Agreements may be limited by applicable law.

     (c) We express no opinion  herein as to compliance or  non-compliance  with
     federal  or state  securities  laws,  including  but not  limited  to,  the
     antifraud  provisions  of any  state or  federal  securities  law,  rule or
     regulation.

     (d) We have acted as counsel to the Company  and the  Signing  Shareholders
     only with respect to certain  corporate  matters,  the  negotiation  of the
     Agreements  and the rendering of these  opinions.  Accordingly,  we may not
     have knowledge of all matters of fact or law relating to the Company or the
     Signing  Shareholders  that may be relevant in connection with the opinions
     herein.  Any  alteration of those facts may adversely  affect our opinions.
     Whenever a statement  herein is qualified by "known to us," "to our current
     actual  knowledge,"  or similar  phrase,  it is intended  to indicate  that
     during the course of our representation of the Company, no information that
     would give us current actual  knowledge of the inaccuracy of such statement
     has come to the attention of those attorneys in this firm who have rendered
     legal  services to the  Company.  However,  except as  otherwise  expressly
     indicated,  we  have  not  undertaken  any  independent   investigation  to
     determine  the  accuracy  of  any  such   statement   (including,   without
     limitation, any search of litigation filings in any court), and any limited
     inquiry  undertaken by us during the  preparation of this letter should not
     be regarded as such an investigation. No inference as to our current actual
     knowledge  of any matters  bearing on the  accuracy  of any such  statement
     should be drawn from the fact of our representation of the Company.

                                      113




Castelle
______________, 1996
 



     (e) With regard to our opinion in paragraph 4 below,  we have  examined and
     relied upon a  certificate  executed by an officer of the  Company,  to the
     effect that the consideration  for all outstanding  shares of capital stock
     of the  Company  was  received  by  the  Company  in  accordance  with  the
     provisions of the applicable Board of Directors resolutions and any plan or
     agreement  relating to the issuance of such shares,  and we have undertaken
     no independent verification with respect thereto.

     (f) With  regard to our  opinion  in  paragraph  5 below  with  respect  to
     material defaults under any material  agreement known to us, we have relied
     solely upon (i) inquiries of officers of the Company,  (ii) a list supplied
     to us by the Company,  a copy of which has been  supplied to your  counsel,
     Cooley Godward Castro  Huddleson & Tatum,  of material  agreements to which
     the Company is a party,  or by which it is bound,  and (iii) an examination
     of  the  items  on  the  aforementioned  list;  we  have  made  no  further
     investigation.

On the  basis of the  foregoing,  in  reliance  thereon  and with the  foregoing
qualifications, we are of the opinion that:

     1. The  Company  has  been  duly  incorporated  and is a  validly  existing
     corporation in good standing under the laws of the State of California.

     2. The  Company  has the  requisite  corporate  power  to own or lease  its
     property and assets and to conduct its  business as it is  currently  being
     conducted  and, to the best of our  knowledge,  is  qualified  as a foreign
     corporation to do business and is in good standing in each  jurisdiction in
     the United  States in which the ownership of its property or the conduct of
     its business  requires such  qualification and where any statutory fines or
     penalties or any  corporate  disability  imposed for the failure to qualify
     would  materially and adversely affect the Company,  its assets,  financial
     condition or operations.

     3. The  Agreements  have been duly and  validly  authorized,  executed  and
     delivered by the Company and constitute valid and binding agreements of the
     Company and the Signing  Shareholders  enforceable  against the Company and
     the respective Signing Shareholders in accordance with their terms.

     4. The  Company's  authorized  capital  stock  consists  of (a) ten million
     (10,000,000)  shares of  Common  Stock,  without  par  value,  of which one
     hundred  forty-one   thousand  sixteen  (141,016)  shares  are  issued  and
     outstanding,  and (b) five million  (5,000,000)  shares of Preferred Stock,
     without  par value,  of which  forty-eight  thousand  thirty-five  (48,035)
     shares have been designated Series A Preferred Stock, without par value, of
     which all such shares are issued and outstanding. The outstanding shares of
     Common Stock and of Preferred Stock have been authorized and validly issued

                                       114




Castelle
______________, 1996
 


     and  are  fully  paid  and  nonassessable.   The  rights,  preferences  and
     privileges of the Series A Preferred Stock are as stated in the Certificate
     of Determination of Preferences of Series A Preferred Stock. To the best of
     our  knowledge,  there are no  options,  warrants,  conversion  privileges,
     preemptive rights or other rights presently  outstanding to purchase any of
     the  authorized but unissued  capital stock of the Company,  other than the
     conversion  privileges of the Series A Preferred  Stock,  rights created in
     connection with the transactions  contemplated by the Agreements and twenty
     thousand  (20,000)  shares  reserved for issuance  under the Company's 1992
     Stock Option Plan, of which  fourteen  thousand  seven  hundred  thirty-one
     (14,731) shares are subject to outstanding options.

     5. The  execution  and  delivery  of the  Agreements  by the Company do not
     violate any provision of the Company's Articles of Incorporation or Bylaws,
     and do not  constitute  a  material  default  under the  provisions  of any
     material  agreement known to us to which the Company is a party or by which
     it is bound, and do not violate or contravene (a) any governmental statute,
     rule or  regulation  applicable  to the  Company  or (b) any  order,  writ,
     judgment, injunction, decree, determination or award which has been entered
     against  the  Company  and  of  which  we  are  aware,   the  violation  or
     contravention  of which would  materially and adversely affect the Company,
     its assets, financial condition or operations.

     6.  To the  best  of our  knowledge,  there  is no  action,  proceeding  or
     investigation  pending or overtly threatened against the Company before any
     court  or  administrative   agency  that  questions  the  validity  of  the
     Agreements or might result, either individually or in the aggregate, in any
     material adverse change in the assets,  financial condition,  or operations
     of the Company.

     7. All  consents,  approvals,  authorizations,  or orders of, and  filings,
     registrations,   and  qualifications  with  any  regulatory   authority  or
     governmental body in the United States required for the consummation by the
     Company  and,  to  our  knowledge,   the  Signing   Shareholders,   of  the
     transactions contemplated by the Agreements, have been made or obtained.


                                      115
 




Castelle
______________, 1996
 

This opinion is intended solely for your use in connection with the transactions
contemplated by the Agreements and is not to be made available to or relied upon
by other persons or entities without our prior written  consent.  Our opinion is
expressly  limited  to the  matters  set forth  above and we render no  opinion,
whether by  implication  or otherwise,  as to any other matters  relating to the
Company or the  Signing  Shareholders.  Our  opinion is  rendered as of the date
hereof,  and we assume no  obligation  to  advise  you of facts,  circumstances,
events or developments which hereafter may be brought to our attention and which
may alter, affect or modify the opinions expressed herein.

Very truly yours,

Graham & James LLP

                                      116




                                  EXHIBIT J

                            FORM OF LEGAL OPINION OF
                     COOLEY GODWARD CASTRO HUDDLESON & TATUM


                                      117





                         [COOLEY GODWARD OPINION LETTER]



____________, 1996

To the Ibex Shareholders
listed on Schedule A hereto

Dear Sir or Madam:

We have acted as counsel for Castelle, a California corporation (the "Company"),
in connection with the merger of Ibex Technologies,  Inc. ("Ibex") with and into
the Company  pursuant to an  Agreement  and Plan of  Reorganization  dated as of
August 22, 1996 (the "Reorganization  Agreement") by and among the Company, Ibex
and the Signing Shareholders listed on Exhibit A-1 and A-2 of the Reorganization
Agreement  (the  "Merger)  and the  issuance  and sale of [eight  hundred  fifty
thousand (850,000)] shares of Castelle Common Stock (the "Shares") in connection
with the Merger. We are rendering this opinion pursuant to Section 6.6(i) of the
Reorganization Agreement.  Except as otherwise defined herein, capitalized terms
used but not defined  herein have the  respective  meanings given to them in the
Reorganization Agreement.

In  connection  with  this  opinion,  we  have  examined  and  relied  upon  the
representations  and  warranties  as to factual  matters  contained  in and made
pursuant to the Reorganization Agreement by the various parties and originals or
copies certified to our satisfaction, of such records, documents,  certificates,
opinions,  memoranda and other  instruments  as in our judgment are necessary or
appropriate to enable us to render the opinion expressed below.  Where we render
an opinion "to the best of our knowledge" or concerning an item "known to us" or
our opinion  otherwise  refers to our knowledge,  it is based solely upon (i) an
inquiry  of  attorneys  within  this firm who  perform  legal  services  for the
Company,  (ii)  receipt of a  certificate  executed by an officer of the Company
covering  such  matters,  and (iii) such other  investigation,  if any,  that we
specifically set forth herein.

In rendering this opinion, we have assumed:  the genuineness and authenticity of
all  signatures  on  original  documents;  the  authenticity  of  all  documents
submitted to us as  originals;  the  conformity  to  originals of all  documents
submitted  to us as copies;  the  accuracy,  completeness  and  authenticity  of
certificates  of public  officials;  and the due  authorization,  execution  and
delivery of all documents (except the due authorization,  execution and delivery
by the  Company  of the  Reorganization  Agreement  and  the  exhibits  thereto,
including the Merger Agreement and the Disclosure  Schedule,  (collectively  the
"Agreements"), where authorization,  execution and delivery are prerequisites to
the effectiveness of such documents.  We have also assumed: that all individuals
executing  and  delivering  documents  had the legal  capacity to so execute and
deliver;  that you have  received all  documents  you were to receive  under the
Agreements;  that the Agreements are obligations  binding upon you; if you are a
corporation  or other  entity,  that  you have  filed  any  required  California

                                      118


franchise or income tax returns and have paid any required California  franchise
or income taxes;  and that there are no extrinsic  agreements or  understandings
among the parties to the Agreements  that would modify or interpret the terms of
the  Agreements  or  the  respective   rights  or  obligations  of  the  parties
thereunder.

Our opinion is  expressed  only with  respect to the federal  laws of the United
States of America and the laws of the State of California. We express no opinion
as to whether the laws of any particular  jurisdiction  apply, and no opinion to
the extent that the laws of any  jurisdiction  other than those identified above
are applicable to the subject matter hereof. We are not rendering any opinion as
to compliance with any antifraud law, rule or regulation.

With  regard to our  opinion  in  paragraph  4 below with  respect  to  material
defaults  under any material  agreement  known to us, we have relied solely upon
(i)  inquiries  of officers of the  Company,  (ii) a list  supplied to us by the
Company, a copy of which has been supplied to your counsel,  Graham & James LLP,
of material agreements to which the Company is a party, or by which it is bound,
and (iii) an examination of the items on the  aforementioned  list; we have made
no further investigation.

On the  basis of the  foregoing,  in  reliance  thereon  and with the  foregoing
qualifications, we are of the opinion that:

     1. The  Company  has  been  duly  incorporated  and is a  validly  existing
corporation in good standing under the laws of the State of California.

     2. The  Agreements  have been duly and  validly  authorized,  executed  and
delivered  by the Company and  constitute  valid and binding  agreements  of the
Company  enforceable  against the Company in accordance with their terms, except
as rights to indemnity  under section 9 of the  Reorganization  Agreement may be
limited  by  applicable  laws  and  except  as  enforcement  may be  limited  by
applicable bankruptcy, insolvency,  reorganization,  arrangement,  moratorium or
other similar laws affecting  creditors'  rights,  and subject to general equity
principles and to limitations on  availability  of equitable  relief,  including
specific performance.

     3.  The  Shares,   when  issued  in  accordance   with  the  terms  of  the
Reorganization  Agreement,  will be duly authorized,  validly issued, fully paid
and non-assessable.

     4. The  execution and delivery of the  Agreements  by the Company  pursuant
thereto do not violate  any  provision  of the  Company's  Amended and  Restated
Articles of  Incorporation  or Bylaws,  and do not constitute a material default
under the provisions of any material  agreement known to us to which the Company
is a party or by which it is bound,  and do not  violate or  contravene  (a) any

                                      119


governmental  statute,  rule or regulation  applicable to the Company or (b) any
order, writ, judgment, injunction, decree, determination or award which has been
entered  against  the  Company  and of  which we are  aware,  the  violation  or
contravention of which would  materially and adversely  affect the Company,  its
assets, financial condition or operations.

     5.  To the  best  of our  knowledge,  there  is no  action,  proceeding  or
investigation pending or overtly threatened against the Company before any court
or administrative  agency that questions the validity of the Agreements or might
result, either individually or in the aggregate,  in any material adverse change
in the assets, financial condition, or operations of the Company.

     All  consents,  approvals,  authorizations,  or  orders  of,  and  filings,
registrations,  and qualifications with any regulatory authority or governmental
body in the United States  required for the  consummation  by the Company of the
transactions contemplated by the Agreements, have been made or obtained.

     Registration  #33-__________ (the "Registration  Statement") filed pursuant
to the Securities  Act of 1933, as amended (the  "Securities  Act"),  has become
effective,  and,  to the best of our  knowledge,  no stop order  suspending  the
effectiveness  of  the  Registration  Statement  or  preventing  the  use of the
associated  Prospectus/Proxy  Statement has been issued and no  proceedings  for
that purpose have been instituted or are pending or threatened by the Securities
and Exchange Commission.

     The Registration  Statement and the Prospectus/Proxy  Statement (except for
the  financial  statements  and  schedules,   other  financial  information  and
statistical data which are included therein and information  concerning Ibex, as
to which we express no opinion) comply as to form in all material  respects with
the requirements of the Securities Act and the rules and regulations thereunder.

                                      120



This opinion is intended solely for your benefit and is not to be made available
to or be relied  upon by any other  person,  firm,  or entity  without our prior
written consent.



Very truly yours,

COOLEY GODWARD CASTRO
HUDDLESON & TATUM


By:  
        Samuel M. Livermore

                                      121







                                   Schedule A


Ney Grant and Betsy Gray-Grant

Clovis Mattos

Curtis Powell

Tucha Limited

Newark Holding S.A.

Teodoro Ramos Gimenez

                                      122








                                    EXHIBIT L

                                ESCROW AGREEMENT

                                      123



                                ESCROW AGREEMENT


     THIS ESCROW  AGREEMENT is entered into as of August __, 1996 (the  "Closing
Date"), by and among:  CASTELLE,  a California  corporation  ("Castelle");  IBEX
TECHNOLOGIES,  INC., a California corporation ("Ibex"); the Shareholders of Ibex
who are listed on Attachment A (the  "Shareholders");  NEY GRANT as agent of the
Shareholders  (the  "Shareholders'  Agent");  and  ___________________  ("Escrow
Agent").

                                    RECITALS

     A. Castelle,  Ibex, and the Shareholders are entering into an Agreement and
Plan of Reorganization of even date herewith (the  "Reorganization  Agreement"),
pursuant to which Ibex shall be merged into Castelle and Ibex shareholders shall
exchange their stock in Ibex for shares of Castelle.

     B. The Reorganization Agreement contemplates the establishment of an escrow
arrangement to secure the  indemnification and other obligations of Ibex and the
Shareholders under the Reorganization Agreement and various related agreements.

     C. Pursuant to Section 10.1 of the Reorganization Agreement, the Designated
Shareholders  have  appointed  the  Designated   Shareholders'  Agent  as  their
attorneys-in-fact for the purposes of this Agreement.

     D. The Designated  Shareholders have agreed to deposit ten percent (10%) of
the total number of shares of Common Stock of Castelle  received pursuant to the
Reorganization Agreement (the "Shares") with Escrow Agent in connection with the
Designated   Shareholders'   performance   of  their   obligations   under   the
Reorganization Agreement.

     E. The Designated Shareholders' Agent and Castelle desire that Escrow Agent
hold the Shares  pursuant to the terms hereof and to  distribute  such Shares in
accordance with the procedures specified herein.

                                    AGREEMENT

     The parties to this Escrow Agreement,  intending to be legally bound, agree
as follows:

SECTION 1. DEFINED TERMS

     Capitalized  terms used and not otherwise  defined in this Escrow Agreement
shall have the meanings assigned to them in the Reorganization Agreement.

                                      124


SECTION 2. ESCROW

     2.1 Shares and Stock  Powers to be Placed in Escrow.  On the Closing  Date,
(i)  Castelle  shall  issue  certificates  for the  Shares  in the  names of the
Designated  Shareholders  evidencing  the shares of Castelle Stock to be held in
escrow  in  accordance  with  this  Escrow  Agreement,  and (ii) the  Designated
Shareholders  shall  deliver to Escrow Agent three stock powers each endorsed by
the  Designated  Shareholders  in  blank  (the  "Stock  Powers").  Ibex  and the
Designated  Shareholders'  Agent shall ensure that all  signatures  on the Stock
Powers delivered to Escrow Agent in accordance with the preceding  sentence have
been  guaranteed by a national bank or New York Stock Exchange  member firm. The
shares and Stock Powers  referred to in this Section 2.1 shall be held by Escrow
Agent in escrow (the "Escrow") in accordance  with the provisions of this Escrow
Agreement.

     2.2 Voting of Shares.  The record  owner of the Shares shall be entitled to
exercise all voting rights with respect to such Shares.

     2.3 Dividends,  Etc. Any cash,  securities or other property  distributable
(whether  by way of  dividend,  stock  split or  otherwise)  in respect of or in
exchange  for any Shares  shall not be  distributed  to the record owner of such
Shares,  but rather shall be held by the Escrow Agent in the Escrow. At the time
any Shares are required to be released from the Escrow to any person pursuant to
this  Escrow  Agreement,  any  cash,  securities  or other  property  previously
distributed  in respect of or in exchange for such shares shall be released from
the Escrow to such person.

     2.4  Transferability.  The interests of the Designated  Shareholders' Agent
and the  Shareholders  in the Escrow and in the Shares held in the Escrow  shall
not be assignable or  transferable,  other than by operation of law. No transfer
of any of such interests by operation of law shall be recognized or given effect
until Castelle shall have received written notice of such transfer.

     2.5  Fractional  Shares.  No fractional  shares of Castelle  Stock shall be
retained in or released from the Escrow  pursuant to this Escrow  Agreement.  In
connection  with any release of shares from the  Escrow,  Castelle  shall make a
cash  payment to the owner of record for such  fractional  share  which  payment
shall be determined utilizing the Stipulated Value of such Share.

     2.6  Receipt  By Escrow  Agent.  Escrow  Agent  acknowledges  receipt  from
Castelle  of a  certificate  representing  the  Shares  and from the  Designated
Shareholders'  Agent  of  stock  powers  executed  in  blank  by the  Designated
Shareholders  with  respect to the  Shares.  Escrow  Agent  accepts  appointment
hereunder and agrees to hold and distribute the Shares in accordance herewith.

SECTION 3. CLAIM PROCEDURES

     Claim Procedures  shall be as set forth in Section 9 of the  Reorganization
Agreement and this Section.

                                      125


     3.1 Response Notice. Within twenty (20) business days after the delivery of
an Officer's  Certificate to the Designated  Shareholders' Agent (with a copy to
the Escrow Agent),  the Designated  Shareholders'  Agent shall deliver to Escrow
Agent and Castelle a written  notice (the  "Response  Notice")  containing:  (i)
instructions to the effect that Shares having a Stipulated  Value (as defined in
Section 5 of this Escrow  Agreement)  equal to the entire Claim Amount set forth
in such Claim  Notice are to be released  from the Escrow to  Castelle;  or (ii)
instructions  to the effect that  Shares  having a  Stipulated  Value equal to a
specified  portion (but not the entire  amount) of the Claim Amount set forth in
such Claim Notice are to be released from the Escrow to Castelle,  together with
a statement that the remaining  portion of such Claim Amount is being  disputed;
or (iii) a statement that the entire Claim Amount set forth in such Claim Notice
is being  disputed.  If no Response  Notice is received by Escrow Agent from the
Designated  Shareholders'  Agent  within  twenty  (20)  business  days after the
delivery of an Officer's Certificate to the Designated Shareholders' Agent, then
the  recipient of such Claim  Notice shall be deemed to have given  instructions
that Shares having a Stipulated Value equal to the entire Claim Amount set forth
in such Claim Notice are to be released to Castelle from the Escrow.

     3.2 Release of Shares to Castelle.

     (a) If the  Designated  Shareholders'  Agent  gives  (or is  deemed to have
     given) instructions that shares of Castelle Stock having a Stipulated Value
     equal to the entire Claim Amount set forth in an Officer's  Certificate are
     to be released  from the Escrow to  Castelle,  then  Escrow  Agent shall be
     authorized to use a Stock Power held in the Escrow to transfer to Castelle,
     from the  Escrow,  Shares  having a  Stipulated  Value  equal to such Claim
     Amount.

     (b) If a Response Notice delivered by the Designated Shareholders' Agent in
     response to an Officer's  Certificate  contains  instructions to the effect
     that Shares having a Stipulated Value equal to a specified portion (but not
     the  entire  amount)  of the  Claim  Amount  set  forth  in such  Officer's
     Certificate are to be released from the Escrow to Castelle, then (i) Escrow
     Agent  shall be  authorized  to use a Stock  Power  held in the  Escrow  to
     transfer to Castelle,  from the Escrow,  Shares  having a Stipulated  Value
     equal  to such  specified  portion  of such  Claim  Amount,  and  (ii)  the
     procedures  set forth in Section 3.2(c) of this Escrow  Agreement  shall be
     followed with respect to the remaining portion of such Claim Amount.

     (c) If a Response Notice delivered by the Designated Shareholders' Agent in
     response to a Claim  Notice  contains a statement  that all or a portion of
     the Claim  Amount set forth in such Claim  Notice is being  disputed  (such
     Claim  Amount or the  disputed  portion  thereof  being  referred to as the
     "Disputed Amount"),  then,  notwithstanding anything contained in Section 4
     of this Escrow Agreement, Escrow Agent shall continue to hold in the Escrow
     (in  addition to any other  Shares  permitted to be retained in the Escrow,
     whether in connection with any other dispute, or otherwise) Shares having a
     Stipulated  Value equal to 125% of the Disputed  Amount.  Such Shares shall
     continue to be held in the Escrow  until such time as (i)  Castelle and the
     Designated  Shareholders' Agent execute a settlement  agreement  containing
     instructions  regarding  the  release of such  Shares,  (ii)  Escrow  Agent
     receives a written decision from the arbitrator assigned to the dispute and
     an application to correct or vacate the arbitration  award can no longer be

                                      126


     filed  pursuant  to the  terms of the  Reorganization  Agreement,  or (iii)
     Escrow Agent receives a copy of a court order  containing  instructions  to
     Escrow  Agent  regarding  the release of such  Shares.  Escrow  Agent shall
     thereupon  release  such  Shares  from the  Escrow in  accordance  with the
     instructions set forth in such settlement  agreement,  arbitration decision
     or court order.  (The parties  acknowledge that it is appropriate to retain
     more than 100% of the Claim Amount in the Escrow in recognition of the fact
     that Castelle may have  underestimated  the aggregate  amount of the actual
     and potential Damages arising from a particular breach.)

SECTION 4. RELEASE OF SHARES TO DESIGNATED SHAREHOLDERS' AGENT

     4.1 Shares to be  Released.  On the date 365 days after the  Closing  Date,
Escrow Agent shall release to the Designated Shareholders' Agent from the Escrow
all  Shares  then  held in the  Escrow,  except  for any  Shares  subject  to an
Officer's Certificate which has been delivered or that are to be retained in the
Escrow in accordance with Section 3.2(c) of this Escrow Agreement.

     4.2  Procedures  for  Releasing  Shares.  Any  release  of  shares  to  the
Designated  Shareholders' Agent pursuant to Section 4.1 of this Escrow Agreement
may be  effected by  utilizing  a  nationally  recognized  overnight  courier to
deliver a stock certificate to the Designated Shareholders' Agent.

SECTION 5. VALUATION OF SHARES HELD IN ESCROW

     For purposes of this Escrow  Agreement,  the "Stipulated  Value" of each of
the Shares held in the Escrow shall be deemed to be equal to $8.00  (adjusted as
appropriate to reflect any stock split,  reverse stock split,  stock dividend or
similar transaction effected by Castelle after the Closing Date).

SECTION 6. FEES AND EXPENSES

     The Shareholders shall reimburse the Designated Shareholders' Agent for all
reasonable  expenses  (including  attorneys'  fees)  incurred by the  Designated
Shareholders'  Agent in connection with the performance of his duties hereunder.
In addition, the Designated  Shareholders' Agent shall be promptly reimbursed by
the Designated  Shareholders,  in proportion to the number of shares of Castelle
Common  Stock  received  by  each of them as a  result  of the  Merger,  for any
payments which the Designated Shareholders' Agent is obligated to make and which
are made to the Escrow Agent pursuant to the indemnification  provisions of this
Escrow Agreement.

                                      127


SECTION 7. PAYMENT OF ESCROW AGENT'S FEES AND EXPENSES

     All fees and expenses (including, without limitation, reasonable attorneys'
fees)  charged by Escrow  Agent for its  activities  pursuant to this  Agreement
shall be paid by Castelle pursuant to the attached fee schedule.

SECTION 8. RIGHTS AND OBLIGATIONS OF ESCROW AGENT

     8.1 Successor Escrow Agent.  Escrow Agent may resign as Escrow Agent at any
time  by  notice  to  the  Designated  Shareholders'  Agent  and  Castelle  (the
"Resignation  Notice").  Upon receipt of the Resignation  Notice, the Designated
Shareholders'  Agent and Castelle shall appoint a successor Escrow Agent,  which
shall be a banking corporation or trust company, organized under the laws of the
United  States or of the State of  California,  with a place of  business in San
Francisco.   Upon  receipt  of  notice  of   appointment   from  the  Designated
Shareholders' Agent and Castelle, Escrow Agent shall promptly deliver the Shares
to such successor. In the event the Designated  Shareholders' Agent and Castelle
do not agree upon a successor and deliver written notice thereof to Escrow Agent
within 60 days following delivery of the Resignation Notice, the Presiding Judge
of the Superior Court of the State of California, in and for the City and County
of  San   Francisco,   shall  appoint  a  successor  in   accordance   with  the
above-mentioned  guidelines,  and Escrow Agent shall promptly deliver the Shares
to such successor.

     8.2  Indemnification.  The  Designated  Shareholders'  Agent and  Castelle,
jointly and severally,  hereby agree to indemnify and hold Escrow Agent harmless
from and against any and all losses,  claims,  damages,  actions, suits or other
charges  incurred by or assessed  against Escrow Agent in the performance of its
duties  hereunder,  except to the extent  resulting  from its own  negligence or
misconduct.

     8.3 Limitation Of Liability.  Escrow Agent shall not incur any liability to
anyone for damages,  losses or expenses  with respect to (a) any action taken or
omitted in good faith upon advice of Escrow  Agent's  counsel given with respect
to  any  questions  relating  to  Escrow  Agent's  duties  and  responsibilities
hereunder,  or (b) any action taken or omitted in reliance  upon any  instrument
(including,  without  limitation,  any Officer's  Certificate or Response Notice
provided  for  herein)  which  Escrow  Agent  shall in good faith  believe to be
genuine,  to have been signed or presented by a proper  person or persons and to
conform with the provisions hereof. Furthermore, in the event Escrow Agent shall
be uncertain as to its rights or obligations  hereunder,  or in the event Escrow
Agent shall receive any communication from the Designated Shareholders' Agent or
Castelle with respect to the Shares which, in the opinion of Escrow Agent, is in
conflict  with any of the  provisions of this  Agreement,  Escrow Agent shall be
entitled to refrain from taking any action until it shall be directed  otherwise
in writing by the Designated  Shareholders'  Agent and Castelle or by order of a
court of competent jurisdiction.

                                      128


     8.4  Controversies.  If any controversy  arises between the parties to this
Agreement,  or with any  other  party,  concerning  the  subject  matter of this
Agreement,  its  terms or  conditions,  Escrow  Agent  will not be  required  to
determine the  controversy or to take any action  regarding it. Escrow Agent may
hold all documents and funds and may wait for settlement of any such controversy
pursuant  to Section  9.11 of the  Reorganization  Agreement  hereof or by final
appropriate legal  proceedings or other means as, in Escrow Agent's  discretion,
Escrow  Agent  may  require,  despite  what may be set forth  elsewhere  in this
Agreement.  In such  event,  Escrow  Agent  will not be liable for  interest  or
damage.

     8.5 No Interest. Notwithstanding any provision to the contrary contained in
any other  agreement  between or among any of the parties  hereto,  Escrow Agent
shall have no interest in the Shares.

     8.6 No  Implied  Obligations.  This  Agreement  sets  forth  the  exclusive
obligations  of Escrow  Agent  with  respect  to any and all  matters  pertinent
hereto,  and no implied duties or obligations of Escrow Agent shall be read into
this Agreement.


SECTION 9. GENERAL

     9.1 Confirmation of Appointment.  The Shareholders  confirm the appointment
and authority of the Designated Shareholders' Agent as set forth in Section 10.1
of Reorganization  Agreement with respect to all matters relating to this Escrow
Agreement.  Any successor to the Designated Shareholders' Agent who is appointed
in  accordance  with  the  provisions  of  Section  10.1  of the  Reorganization
Agreement  shall  be  deemed  to be the  "Designated  Shareholders'  Agent"  for
purposes of this Escrow Agreement.  Any document executed or action taken by the
Shareholders' Agent shall be binding upon all of the Shareholders.

     9.2 Other Agreements. Nothing in this Escrow Agreement is intended to limit
any of Castelle's  rights,  or any obligation of any Shareholder or Ibex,  under
the Reorganization Agreement.

     9.3 Notices. Any notice or other communication  required or permitted to be
delivered to any party under this Escrow Agreement shall be in writing and shall
be deemed  properly  delivered,  given and received when  delivered (by hand, by
registered  mail, by courier or express delivery service or by facsimile) to the
address or facsimile  telephone  number set forth beneath the name of such party
below (or to such other  address  or  facsimile  telephone  number as such party
shall have specified in a written notice given to the other parties hereto):

                                      129


if to the Designated Shareholders' Agent or any of the Shareholders:

                      NEY GRANT
                      2725 Romer Boulevard
                      Pollock Pines, CA  95726
                      Facsimile:  (916) 647-2055

               if to Castelle:

                      CASTELLE

                      3255-3 Scott Boulevard
                      Santa Clara, California 95054
                      Attn:  President
                      Facsimile:  (408) 654-4699

               if to Escrow Agent:

                      --------------------

                      --------------------

                      --------------------

     9.4  Counterparts.  This  Escrow  Agreement  may be executed in two or more
counterparts,  each of  which  shall be  deemed  an  original,  and all of which
together shall constitute one and the same instrument.

     9.5 Time of the Essence. Time is of the essence of this Escrow Agreement.

     9.6 Headings.  The underlined  headings  contained in this Escrow Agreement
are for convenience of reference only,  shall not be deemed to be a part of this
Escrow   Agreement  and  shall  not  be  referred  to  in  connection  with  the
construction or interpretation of this Escrow Agreement.

     9.7 Governing Law; Venue.

     (a) This Escrow  Agreement  shall be  construed  in  accordance  with,  and
     governed in all respects by, the internal  laws of the State of  California
     (without giving effect to principles of conflicts of laws).

     (b)  Subject  to  the  arbitration   provisions  of  Section  9.11  of  the
     Reorganization  Agreement,  any  legal  action  or other  legal  proceeding
     relating to this Escrow  Agreement or the  enforcement  of any provision of
     this Escrow Agreement may be brought or otherwise commenced in any state or
     federal court located in the State of California. Each party to this Escrow
     Agreement:

                                      130


          (i) expressly and irrevocably consents and submits to the jurisdiction
          of each state and  federal  court  located in the State of  California
          (and each  appellate  court  located  in the State of  California)  in
          connection with any such legal proceeding;

          (ii) agrees that each state and federal  court located in the State of
          California shall be deemed to be a convenient forum; and

          (iii)  agrees  not to  assert  (by  way of  motion,  as a  defense  or
          otherwise),  in any such legal  proceeding  commenced  in any state or
          federal court located in the State of California,  any claim that such
          party is not subject  personally  to the  jurisdiction  of such court,
          that such legal proceeding has been brought in an inconvenient  forum,
          that the venue of such  proceeding  is  improper  or that this  Escrow
          Agreement or the subject  matter of this Escrow  Agreement  may not be
          enforced in or by such court.

     (c) Unless  addressed in Section 9.7(b) of this Escrow  Agreement,  nothing
     contained  in this Escrow  Agreement  shall be deemed to limit or otherwise
     affect the right of any party  hereto to commence any legal  proceeding  or
     otherwise  proceed  against  any other  party  hereto in any other forum or
     jurisdiction.

     9.8 Successors and Assigns; Parties in Interest.

     (a)  Subject to  Sections  2.4 and 9.8(b) of this  Escrow  Agreement,  this
     Escrow Agreement shall be binding upon: Ibex and its successors and assigns
     (if any); the Designated Shareholders' Agent and the Shareholders and their
     respective  estates,  successors and assigns (if any); and Castelle and its
     successors and assigns (if any).  This Escrow  Agreement shall inure to the
     benefit  of:  Ibex;  the  Shareholders;  Castelle;  the  other  Indemnitees
     (subject  to  Section  9.8  of  the  Reorganization   Agreement);  and  the
     respective successors (if any) of the foregoing.

     (b) Castelle  may freely  assign any or all of its rights under this Escrow
     Agreement,  in whole or in part, to any other person without  obtaining the
     consent  or  approval  of any other  party  hereto or of any other  person.
     Castelle may not delegate its  obligations  under this Escrow  Agreement to
     any other person without the prior consent of the Designated  Shareholders'
     Agent. None of the Shareholders, the Designated Shareholders' Agent or Ibex
     shall be  permitted to assign any of his, her or its rights or delegate any
     of  his,  her  or its  obligations  under  this  Escrow  Agreement  without
     Castelle's prior reasonable written consent.

     9.9 Waiver.

     (a) No  failure  on the part of any person to  exercise  any power,  right,
     privilege or remedy under this Escrow  Agreement,  and no delay on the part
     of any person in  exercising  any power,  right,  privilege or remedy under
     this Escrow  Agreement,  shall  operate as a waiver of such  power,  right,
     privilege or remedy;  and no single or partial  exercise of any such power,
     right,  privilege  or remedy shall  preclude any other or further  exercise
     thereof or of any other power, right, privilege or remedy.

                                      131


     (b) No person shall be deemed to have waived any claim  arising out of this
     Escrow  Agreement,  or any power,  right,  privilege  or remedy  under this
     Escrow Agreement,  unless the waiver of such claim, power, right, privilege
     or remedy is expressly set forth in a written  instrument duly executed and
     delivered  on  behalf  of such  person;  and any such  waiver  shall not be
     applicable or have any effect  except in the specific  instance in which it
     is given.

     9.10  Amendments.  This  Escrow  Agreement  may not be  amended,  modified,
altered  or  supplemented  other  than by means  of a  written  instrument  duly
executed and  delivered on behalf of Castelle and the  Designated  Shareholders'
Agent.

     9.11  Severability.  In  the  event  that  any  provision  of  this  Escrow
Agreement,  or the  application  of any such  provision  to any person or set of
circumstances,   shall  be   determined  to  be  invalid,   unlawful,   void  or
unenforceable  to any extent,  the remainder of this Escrow  Agreement,  and the
application of such provision to persons or circumstances other than those as to
which it is determined to be invalid, unlawful, void or unenforceable, shall not
be impaired or otherwise affected and shall continue to be valid and enforceable
to the fullest extent permitted by law.

     9.12 Entire Agreement.  This Escrow Agreement, the Reorganization Agreement
and the  Exhibits  thereto  set forth the entire  understanding  of the  parties
relating  to the subject  matter  hereof and  thereof  and  supersede  all prior
agreements and  understandings  among or between any of the parties  relating to
the subject matter hereof and thereof.

     9.13 Construction.

     (a) For purposes of this Escrow  Agreement,  whenever the context requires:
     the singular number shall include the plural, and vice versa; the masculine
     gender shall include the feminine and neuter  genders;  the feminine gender
     shall include the masculine and neuter genders; and the neuter gender shall
     include the masculine and feminine genders.

     (b) The parties  hereto agree that any rule of  construction  to the effect
     that ambiguities are to be resolved against the drafting party shall not be
     applied in the construction or interpretation of this Escrow Agreement.

     (c) As used in this Escrow Agreement,  the words "include" and "including,"
     and variations thereof, shall not be deemed to be terms of limitation,  but
     rather shall be deemed to be followed by the words "without limitation."

     (d) Except as otherwise indicated,  all references in this Escrow Agreement
     to "Sections" are intended to refer to Sections of this Escrow Agreement.

                                      132




     IN WITNESS  WHEREOF,  the parties have executed this Escrow Agreement as of
the date first above written.

                              CASTELLE,

                              a California corporation







                              By:



                              IBEX TECHNOLOGIES, INC.,
                              a California corporation




                              By:
                              Ney Grant, President











                             
                              Shareholders' Agent



                              ESCROW AGENT

                                      133








                                  ATTACHMENT A

                                  SHAREHOLDERS





Ney Grant and Betsy Gray-Grant

Clovis Mattos

Curtis Powell

                                      134




                                  ATTACHMENT B

                            ESCROW AGENT FEE SCHEDULE

                                      135




                                    EXHIBIT M

                            FORM OF IRREVOCABLE PROXY


                                      136





                                IRREVOCABLE PROXY


     ____________________  ("Shareholder"),  a shareholder of Ibex Technologies,
Inc., a California  corporation (the  "Company"),  hereby  irrevocably  appoints
Castelle, a California  corporation,  the attorney and proxy of the undersigned,
with full  power of  substitution  and  resubstitution,  to vote the  __________
shares of voting common stock of the Company owned of record by Shareholder (the
"Shares") with respect to the following matters (the "Identified Matters"):

     (a) the Reorganization Agreement (as herein defined), the Merger (as herein
     defined),  and the other  transactions  contemplated by the  Reorganization
     Agreement;

     (b)  any  proposal  made  in  opposition  to or  in  competition  with  the
     consummation of the Merger;

     (c) any proposal  contemplating  any transaction  involving:  (i) the sale,
     license,  disposition or  acquisition  of all or a material  portion of the
     Company's  business  or  assets;  or  (ii)  the  issuance,  disposition  or
     acquisition  of (A) any  capital  stock or  other  equity  security  of the
     Company, (B) any option, call, warrant or right (whether or not immediately
     exercisable)  to acquire,  or otherwise  relating to, any capital  stock or
     other equity  security of the Company,  or (C) any security,  instrument or
     obligation that is or may become  convertible  into or exchangeable for any
     capital stock or other equity security of the Company; or

     (d)  any  merger,  consolidation,  business  combination,  share  exchange,
     reorganization or similar transaction involving the Company; and

     (e) any other  action or  agreement  that could  reasonably  be expected to
     result  in  (i) a  breach  of  any  representation,  warranty  covenant  or
     obligation  of  the  Company  or  Shareholder   under  the   Reorganization
     Agreement,  or under any other agreement  executed on behalf of the Company
     or  Shareholder,  or  (ii)  any  of the  conditions  to  the  Company's  or
     Castelle's  obligations  under  the  Reorganization   Agreement  not  being
     satisfied.

     This Proxy shall terminate at such time (if ever) as that certain Agreement
and Plan of  Reorganization  dated as of August  __,  1996 (the  "Reorganization
Agreement")  among  Castelle,   the  Company,   Shareholder  and  certain  other
shareholders  of the  Company,  providing  for the  merger of the  Company  into
Castelle  (the  "Merger"),  shall  have  been  validly  terminated  or closed in
accordance with its terms. Upon the execution hereof, all prior proxies given by
Shareholder  with respect to the Shares are hereby  revoked,  and no  subsequent
proxies will be given.  This Proxy is  irrevocable,  is coupled with an interest
and is granted in  consideration  of Castelle  entering into the  Reorganization
Agreement.  The attorneys and proxies  appointed  pursuant to this Proxy will be
empowered  (at  all  times  prior  to  the  termination  of  the  Reorganization
Agreement) to exercise (in their  discretion and in such manner as they may deem
appropriate)  all voting and other  rights of  Shareholder  with  respect to the
Shares (including,  without limitation, the power to execute and deliver written

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consents with respect to the Shares), with respect to the Identified Matters, at
every  meeting of the  shareholders  of the Company  (and every  adjournment  or
postponement  thereof)  or by  written  consent  in lieu of such a  meeting,  or
otherwise.

     This  Proxy  shall  be  binding  upon  the  Shareholder  and  his  personal
representatives,  executors,  administrators,  estates,  heirs,  successors  and
assigns (if any).  This Proxy  shall  inure to the  benefit of Castelle  and its
respective successors and assigns (if any).







Dated:  ______________, 1996                    _______________________________
                                                          Shareholder

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