Exhibit 99.4

                            LINE OF CREDIT AGREEMENT

         This Line of Credit Agreement (this "Agreement") is dated as of March
28, 2003 by and between Digilog, Inc., a Pennsylvania corporation ("Debtor")
and Alethea Limited Partnership, a Delaware limited partnership ("Lender").

         WHEREAS, the Debtor seeks to establish a line of credit with the
Lender, and the Lender desires to extend funds to the Debtor through a line of
credit, on the terms and conditions set forth herein.

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows.

         Section 1.        The Line of Credit and the Note.

                  A.       Subject to the terms and conditions of this
Agreement, the Lender hereby offers, and the Debtor hereby accepts, a line of
credit for the Debtor (the "Line of Credit"), pursuant to which the Debtor may
borrow up to an aggregate of One Million Dollars ($1,000,000) (the "Credit
Limit") during the Term thereof (as defined below). Advances under the Line of
Credit shall be made by the Lender in accordance with the terms set forth in
this Agreement, and the repayment obligations incurred by such advances shall be
represented by the term promissory note, dated as of the date hereof, issued by
the Debtor to the Lender in the form of Exhibit A hereto in the original
principal amount of up to One Million Dollars ($1,000,000) (the "Note").

                  B.       Advances and Repayments.
                           ------------------------

                           (i)      ADVANCES. At any time commencing on the date
hereof and throughout the Term (as defined in Section 1(C) below), the Debtor
may request advances to be made to it under the Line of Credit by sending
written notice to the Lender at its address appearing in the "Notices" section
hereof, indicating the total amount of funds sought in such advance (each such
request, a "Draw"). The minimum amount in any Draw requested by the Debtor shall
be at least One Hundred Thousand Dollars ($100,000). Within three Business Days
of its receipt of such notice from the Debtor, the Lender shall advance to the
Debtor an amount equal to the requested Draw. Simultaneously with advancing such
funds to the Debtor, the Lender shall have the right to notate on the SCHEDULE A
attached to the Note, the amount of money advanced by it pursuant to such Draw,
together with the sum total of all advances made by the Lender under the Line of
Credit through such date. In the absence of manifest error, the Schedule
attached to the Note shall be deemed a conclusive accounting of the sums
advanced to the Debtor.



                                    (a)      For purposes of this Agreement, a
"Business Day" shall mean any day on which commercial banks located in Florida
are required or permitted by law to be open for the purpose of conducting
commercial banking business.

                           (ii)     Repayments. The Debtor shall have the right
at any time during the Term to repay any or all of the principal amounts
outstanding under the Line of Credit, provided that the minimum amount of any
repayment shall be at least One Hundred Thousand Dollars ($100,000) and that
such repayment is accompanied by all accrued and unpaid interest thereon and
other amounts (if any) incurred in connection therewith through the date of
repayment. There shall be no penalty or premium assessed with respect to any
repayment of principal prior to the Maturity Date (as defined below). The Debtor
shall give notice of any repayment to the Lender at least three Business Days in
advance of such repayment, indicating therein the total amount being repaid and
the anticipated repayment date. On such repayment date, the Debtor shall repay
to the account of the Lender the total amount being repaid. Upon its receipt of
a repayment, the Lender shall have the right to notate on the Schedule A
attached to the Note, the amount of money so repaid, together with the sum total
of all repayments made through such date. In the absence of manifest error, the
Schedule attached to the Note shall be deemed a conclusive accounting of the
sums repaid by the Debtor.

                  C.       The Term. The Debtor may request Draws under the Line
of Credit, in amounts up to the Credit Limit, at any time and from time to time
after the date hereof and through the first anniversary of the date hereof (the
"Maturity Date", and the period extending from date hereof through the Maturity
Date, the "Term" of the Line of Credit). Unless earlier accelerated in
accordance with Section 4(A)(i) hereof, on the Maturity Date, all outstanding
advances made hereunder, together with all interest accrued thereon and all
other amounts (if any) incurred in connection therewith, shall be due and
payable in full to the Lender.

                  D.       The Guarantee. The prompt payment and performance of
all of the obligations of the Debtor under the Line of Credit and the Note shall
be guaranteed by Numerex Corp., a Pennsylvania corporation and the parent
corporation of the Debtor ("Numerex") pursuant to the terms of a Guarantee in
the form of Exhibit B hereto (the "Guarantee"), to be executed and delivered
simultaneously herewith.

                  E.       Security for the Obligations. Simultaneously with the
execution and delivery hereof, the Debtor and Numerex shall execute and deliver
to the Lender a security and pledge agreement in the form of Exhibit C hereto
(the "Security and Pledge Agreement"). Pursuant to the Security and Pledge
Agreement, the Debtor and Numerex shall provide the collateral described therein
as security for the obligations to the Lender under the Line of Credit and the
Note.

         Section 2.        Other Terms and Conditions of the Line of Credit.

                  A.       Interest.



                           (i)      Interest Rate. Subject to subsection (iii)
below, from the date hereof through and including the Maturity Date, interest
shall accrue on all outstanding Draws advanced under the Line of Credit from
time to time at a fixed rate equal to ten percent (10%) per annum (the "Interest
Rate"). Interest shall be calculated on the basis of a year of 360 days and
shall be payable for the actual number of days elapsed.

                           (ii)     Monthly Interest. Interest accrued hereunder
shall be payable by the Debtor to the Lender in cash monthly in arrears, for
each month or portion thereof during which balances were outstanding hereunder.
Interest shall be due and payable on the first day of each month or, if such day
is not a Business Day, on the next succeeding Business Day (with interest
accrued through such date). The Lender shall have the right but not the
obligation, at its sole discretion, to waive receipt of its monthly interest
payment due hereunder by written notice thereof to the Debtor. In such an
occurrence, with no Event of Default hereunder, interest payable to the Lender
for that month shall be capitalized, and interest shall thereafter accrue
thereon at the Interest Rate through the Maturity Date, at which time such
deferred payment plus all accrued and unpaid interest thereon shall be due and
payable. Interest accruing on such deferred payment shall be combined with, and
payable on the same date as, all other monthly interest payable to the Lender
hereunder.

                           (iii)    Default Interest Rate. After the occurrence
and during the continuation of an Event of Default (as defined in Section 4
below), additional interest shall accrue on the outstanding principal balance
due under the Line of Credit at a rate equal to one and one-half percent (1.5%)
per month in excess of the Interest Rate. Interest accruing under this Section
2(A)(iii) shall be due and payable in cash upon demand by the Lender.

                           (iv)     Maximum Interest Rate. Notwithstanding
anything contained herein to the contrary, if a court of competent jurisdiction
determines in a final order that the rate of interest payable under the Line of
Credit exceeds the highest rate of interest permissible under law (the "Maximum
Lawful Rate"), then so long as the Maximum Lawful Rate would be so exceeded, the
rate of interest payable shall be equal to the Maximum Lawful Rate; provided,
however, that if at any time thereafter the rate of interest payable thereunder
is less than the Maximum Lawful Rate, the Debtor shall continue to pay interest
at the Maximum Lawful Rate until such time as the total interest received by the
Lender is equal to the total interest that would have been received had the
interest rate payable under the Line of Credit been (but for the operation of
this paragraph) the interest rate payable since the date hereof as otherwise
provided by the terms hereof. Thereafter, interest shall be paid at the rate(s)
of interest and in the manner provided in this Section 2(A) unless and until the
rate of interest again exceeds the Maximum Lawful Rate, and at that time this
paragraph shall again apply. In no event shall the total interest received by
the Lender pursuant to the terms hereof exceed the amount that it could lawfully
have received had the interest due under the Line of Credit been calculated for
the full term hereof at the Maximum Lawful Rate. If the Maximum Lawful Rate is
calculated pursuant to this paragraph, such interest shall be calculated at a
daily rate equal to the Maximum Lawful Rate divided by the number of days in the
year in which such calculation is made. If, notwithstanding the provisions of
this Section 2(A)(iv), a court of competent jurisdiction shall finally determine
that the Lender has received interest in excess of the Maximum Lawful Rate, the
Lender shall, to the extent permitted by applicable law, promptly apply such
excess to the outstanding principal



balance due under the Note and thereafter shall refund any excess to the Debtor
or as a court of competent jurisdiction may otherwise order.

                  B.       Fees. There shall be no commitment fee payable in
connection with this Line of Credit, nor shall there be any unused facility fee
payable in the event that less than all of the funds available under the Line of
Credit are drawn.

                  C.       Use of Proceeds. The Debtor shall apply all advances
received under the Line of Credit for general corporate purposes, and shall
specifically be permitted to use any proceeds hereunder to pay dividends or make
loans to its sole shareholder, at the Debtor's discretion. No proceeds shall be
used to purchase or carry, or to reduce or retire or refinance any credit
incurred to purchase or carry, any margin stock (within the meaning of
Regulations U and X of the Board of Governors of the Federal Reserve System) or
to extend credit to others for the purpose of purchasing or carrying any such
margin stock.

                  D.       General Payment Terms. All amounts advanced under the
Line of Credit, together with all accrued interest thereon and other amounts, if
any, incurred thereunder or in connection therewith, shall be due and payable on
the Maturity Date. All payments shall be made in lawful money of the United
States of America in immediately available funds to such bank account as the
Lender shall specify in writing to the Debtor. The Debtor shall make payments
under the Line of Credit not later than 1:00 p.m. (Eastern Standard Time) on the
Maturity Date or such earlier repayment date, as applicable. All amounts
received by the Lender shall be applied first, to any costs or expenses due to
it pursuant to the terms hereof or in enforcement of its rights in respect
hereof, second, to accrued interest, and third to unpaid principal. Failure to
pay any balances outstanding under the Line of Credit promptly when due shall
entitle the Lender to exercise any remedies specified herein, under the
Guarantee, the Security and Pledge Agreement, the UCC (as defined hereinafter),
or that may be otherwise available at law or in equity.

                           (i)      For purposes of this Agreement, "UCC" shall
mean the Uniform Commercial Code as in effect from time to time in the State of
Florida.

         Section 3.        Affirmative Covenants. From the date of this
Agreement and during the Term hereof or until such time as all amounts due
hereunder and under the Note shall be paid in full, each of the Debtor and
Numerex agrees that it shall, and Numerex shall cause its subsidiaries to:

                  A.       maintain their corporate existence and names;

                  B.       comply with all applicable laws, statutes, orders,
judgments, decrees, injunctions, rules, regulations, franchises, permits,
authorizations and other requirements, except where the failure to so comply
could not reasonably be expected to have a material adverse effect on the
assets, operations, business, condition (financial or otherwise), results of
operations or prospects of the Debtor, Numerex and Numerex's other subsidiaries,
considered as a whole, or on the Debtor's ability to perform its obligations
hereunder and under the Note (a "Material Adverse Effect");



                  C.       maintain their properties in reasonably good working
order;

                  D.       promptly pay all taxes, assessments, claims and other
governmental charges which, if unpaid, might cause a lien to be imposed on their
respective properties;

                  E.       maintain all insurance on their properties in
accordance with standard industry practices;

                  F.       keep books of account reflecting true and complete
entries of all their dealings and transactions; and

                  G.       provide written notice to the Lender of any event
which constitutes, or with the passage of time or giving of notice would
constitute, an Event of Default hereunder or could otherwise give rise to a
Material Adverse Effect.

         Section 4.        Events of Default.

                  A.       Each of the following shall constitute an Event of
Default hereunder, whatever the reason for such event and whether or not it
shall be voluntary or involuntary or be effected by operation of law or pursuant
to any judgment or order of any court or any order, rule or regulation of any
governmental or non-governmental body:

                           (i)      subject to the granting of a waiver under
Section 2(A)(ii) hereof, the failure of the Debtor to pay any principal,
interest or other amount incurred under the Line of Credit when due; or

                           (ii)     the Debtor shall violate or be in default
under any other provision of this Agreement, the Note, or the Security and
Pledge Agreement which violation or breach shall not be cured within thirty (30)
days after notice thereof is received by the Debtor from the Lender; or

                           (iii)    Numerex shall be in default under any
provision of the Guarantee or the Security and Pledge Agreement, which default
shall not be cured within thirty (30) days after notice thereof is received by
Numerex from the Lender; or

                           (iv)     the Debtor or Numerex shall fail to pay its
debts generally as they come due, shall make an assignment for the benefit of
creditors, or shall file any petition or action for relief under any bankruptcy,
reorganization, insolvency or moratorium law, or any other law or laws for the
relief of, or relating to, debtors; or

                           (v)      an involuntary petition shall be filed under
any bankruptcy statute against the Debtor or Numerex, or a custodian, receiver,
trustee, assignee for the benefit of creditors (or other similar official) shall
be appointed to take possession, custody, or control of any of the Debtor's or
Numerex's properties, unless such petition or appointment is set aside or
withdrawn or ceases to be in effect within sixty (60) days from the date of said
filing or appointment or an order for relief shall be entered in any such
involuntary action; or



                           (vi)     the Debtor or Numerex (a) shall fail to make
any payment when due (whether by scheduled maturity, required prepayment,
acceleration or otherwise) with respect to any other material indebtedness, or
(b) shall otherwise default under any agreement relating to its indebtedness,
and the effect of such default is (1) to cause such indebtedness to become due
prior to the stated maturity thereof, (2) the imposition of a lien on, or a
seizure of, a material portion of the Debtor's or Numerex's assets; or

                           (vii)    the Debtor or Numerex shall become subject
to a nonappealable judgment or judgments which, considered individually or in
the aggregate, could reasonably be expected to have a Material Adverse Effect;
or

                           (viii)   the Debtor shall at any time after the date
hereof issue or incur any indebtedness ranking senior to the Note, or the Debtor
shall repay, prior to the Maturity Date, any indebtedness subordinate to the
Note, in each case without the prior written consent of the Lender; or

                           (ix)     the Debtor or Numerex shall undergo a Change
of Control (as defined below), or the shareholders of the Debtor or Numerex
shall approve any transaction, the effect of which is to cause a Change of
Control of the Debtor or Numerex, respectively.

                                    (a)      For purposes of this Agreement,
"Change of Control" shall mean any of the following:

                                             (1)      any 'person' or 'group'
(within the meaning of Sections 13(d) and 14(d)(2) of the Securities Exchange
Act of 1934, as amended, and the applicable rules and regulations thereunder)
shall become the `beneficial owner(s)' (as defined in said Rule 13d-3) of shares
of stock of the Debtor or of Numerex, either directly or indirectly, that
entitle such holder to control more than fifty percent (50%) of the voting stock
of the Debtor or of Numerex;

                                             (2)      approval by the
stockholders of the Debtor or of Numerex, or the consummation of, any merger,
reorganization, consolidation, share exchange, recapitalization, restructuring
or other business combination in which the Debtor or Numerex, as applicable, is
not the surviving party;

                                             (3)      the sale, assignment,
lease or other disposition (whether in one transaction or a series of
transactions) of all or substantially all of the assets of the Debtor or of
Numerex; or

                                             (4)      a majority of the board of
directors of the Debtor or of Numerex incumbent as of the date hereof, or their
duly elected successors, shall cease to be directors of the Debtor or of
Numerex, respectively.

         Section 5.        Remedies on Default



                  A.       Declaration of Default. Except as set forth in
Sections 5(A)(i) below, an Event of Default shall exist under the Line of Credit
and the remedies hereunder shall be triggered at such time as the Lender shall
so declare in writing to the Debtor.

                           (i)      The Lender shall not be obligated to declare
the occurrence of an Event of Default hereunder with respect to the events
described in Sections 4(A)(iii) and (iv) hereof, upon the occurrence of which an
Event of Default shall exist hereunder immediately and automatically, without
further notice, demand or action of any kind on behalf of any party.

                  B.       Available Remedies. Upon the occurrence and during
the continuation of an Event of Default, the Lender may do any or all of the
following:

                           (i)      the Lender shall have the right to declare
all balances outstanding under the Note or arising hereunder, immediately due
and payable in full, except that upon the occurrence of an Event of Default as
described in Sections 4(A)(iii) and (iv), all such balances shall immediately
and automatically become due and payable, without notice, demand, presentment or
action of any kind by the Lender, all of which are hereby waived by the Debtor;

                           (ii)     the Lender shall have the right to seek
satisfaction from Numerex of any of the Debtor's outstanding obligations
pursuant to the terms of the Guarantee;

                           (iii)    the Lender shall have the right to exercise
any or all of the remedies specified under the Security and Pledge Agreement;
and

                           (iv)     the Lender may exercise any or all of its
rights and remedies under law (including, without limitation, all remedies
provided under the UCC) or in equity.

                  C.       Non-Exclusive Remedies. No remedy herein conferred or
reserved is intended to be exclusive of any other available remedy or remedies,
but each and every such remedy shall be cumulative and shall be in addition to
every other remedy now or hereafter existing at law or in equity or by statute.

                  D.       General. All of the Debtor's obligations hereunder
and under the Note are absolute and unconditional. No delay or omission to
exercise any right or power accruing upon any default, omission or failure of
performance hereunder shall impair any such right or power or shall be construed
to be a waiver thereof, but any such right or power may be exercised from time
to time and as often as may be deemed expedient. In order to exercise any remedy
reserved to the Lender, it shall not be necessary to give any notice, and the
Debtor hereby expressly waives presentment, demand, protest or notice of any
kind. To the fullest extent permitted by law, the Debtor will not plead, claim
or take any benefit or advantage of any statute, law, rule or regulation would
could prohibit, delay or forgive the Debtor from paying any or all amounts
arising hereunder or under the Note, or which may affect the enforceability of
any of the covenants and agreements set forth herein.



         Section 6.        Miscellaneous.

                  A.       Notices. All notices, requests and other
communications to any party hereunder shall be in writing and shall be effective
(i) if given by certified U.S. mail, upon the date so certified as delivered;
(ii) if given by overnight courier, on the next Business Day; (iii) if given by
hand-delivery, upon such delivery; (iv) if given by email, upon electronic
notification of delivery; or (iv) if given by facsimile, upon receipt of
successful transmission. Notices hereunder shall be mailed or faxed as follows:

         If to the Lender:          Alethea Limited Partnership
                                    4193 Las Palmas Way
                                    Sarasota, FL 34238
                                    Attention: Mr. Stratton Nicolaides
                                    Facsimile: (941) 925-9302

         If to the Debtor:          Digilog, Inc.
                                    1600 Parkwood Circle
                                    Atlanta, GA 30339
                                    Attention: President
                                    Facsimile: (770) 693-5951

         If to Numerex:             Numerex Corp.
                                    1600 Parkwood Circle
                                    Atlanta, GA 30339
                                    Attention: President
                                    Facsimile: (770) 693-5951

         with a copy to:            Andrew J. Ryan, Esq.
                                    Salisbury & Ryan
                                    1325 Avenue of the Americas
                                    New York, NY 10019
                                    Facsimile: (212) 977-4668

                  B.       No Waiver. No delay or failure on the part of the
Lender to exercise any right, power or privilege granted under this Agreement or
the Note or available at law or in equity, shall impair any such right, power or
privilege or be construed as a waiver of any Event of Default or any
acquiescence therein. No single or partial exercise of any such right, power or
privilege shall preclude the further exercise of such right, power or privilege.
No waiver shall be valid against the Lender unless made in writing and signed by
the Lender, and then only to the extent expressly specified therein.

                  C.       Expenses. Provided that the Lender is in compliance
with all of its obligations under this Line of Credit Agreement, the Debtor
agrees to pay all of the reasonable costs and expenses incurred by the Lender
(including but not limited to the fees and disbursements of its counsel) based
upon, arising out of or in any way related to the Lender's relationship with the
Debtor or any of the Debtor's affiliates, including but not limited to the
enforcement of the



Lender's rights under this Agreement, the Note, the Guarantee or the Security
and Pledge Agreement.

                  D.       Amendments. No provision of this Agreement or the
Note may be amended or waived unless in writing and consent to by the Lender.

                  E.       Successors and Assigns. The provisions of this
Agreement and the Note shall be binding upon and inure to the benefit of the
parties hereto and thereto and their respective permitted successors and
assigns. The Debtor may not assign or otherwise transfer any of its duties or
obligations hereunder or under the Note to any person or entity without the
prior written consent of the Lender. The Lender shall have the right to transfer
and assign any or all of its obligations and rights hereunder and under the Note
to any party without the consent of (but with notice to) the Debtor.

         F.       Governing Law. The provisions hereof shall be governed by and
construed in accordance with the laws of the State of Florida without regard to
the conflict of law principles thereof.

         G.       CONSENT TO JURISDICTION. THE DEBTOR EXPRESS AND IRREVOCABLY
CONSENTS THAT ANY LEGAL ACTION OR PROCEEDING AGAINST IT UNDER, ARISING OUT OF,
OR IN ANY MANNER RELATING TO THIS AGREEMENT OR THE NOTE REFERENCED HEREIN SHALL
BE BROUGHT IN THE STATE OR DISTRICT COURTS OF THE STATE OF FLORIDA AND THAT
SERVICE OF PROCESS MAY BE MADE UPON IT IN ANY SUCH SUIT OR ACTION BY SERVICE OF
PROCESS AS PROVIDED BY FLORIDA LAW. THE DEBTOR, BY ITS EXECUTION AND DELIVERY OF
THIS AGREEMENT AND THE NOTE, EXPRESSLY AND IRREVOCABLY CONSENTS AND SUBMITS TO
THE PERSONAL JURISDICTION OF ANY OF SUCH COURTS IN ANY SUCH ACTION OR PROCEEDING
AND HEREBY EXPRESSLY AND IRREVOCABLY WAIVES TO THE FULLEST EXTENT PERMITTED BY
LAW, ANY OBJECTION, CLAIM OR DEFENSE IN ANY SUCH ACTION OR PROCEEDING BASED ON
ANY ALLEGED LACK OF PERSONAL JURISDICTION, IMPROPER VENUE OR FORUM NON
CONVENIENS OR ANY SIMILAR BASIS. THE LENDER AND THE DEBTOR AGREE THAT FINAL
JUDGMENT IN ANY SUCH CIVIL SUIT OR ACTION SHALL BE CONCLUSIVE AND BINDING UPON
IT AND SHALL BE ENFORCEABLE AGAINST IT BY SUIT UPON SUCH JUDGMENT IN ANY COURT
OF COMPETENT JURISDICTION.

         H.       WAIVER OF JURY TRIAL. THE LENDER AND THE DEBTOR KNOWINGLY,
VOLUNTARILY, INTENTIONALLY, AND IRREVOCABLY WAIVE THE RIGHT EITHER OF THEM MAY
HAVE TO A TRIAL BY JURY IN RESPECT TO ANY LITIGATION, WHETHER IN CONTRACT OR
TORT, AT LAW OR EQUITY, BASED HEREON, OR ARISING OUT OF, UNDER OR IN CONNECTION
WITH THIS AGREEMENT, THE NOTE, THE GUARANTEE, THE SECURITY AND PLEDGE AGREEMENT
AND ANY OTHER DOCUMENT OR INSTRUMENT CONTEMPLATED TO BE EXECUTED IN CONJUNCTION
HEREWITH, OR ANY COURSE OF CONDUCT, COURSE OF DEALING, STATEMENTS (WHETHER
VERBAL OR WRITTEN) OR ACTIONS OF THE LENDER OR THE DEBTOR. THIS PROVISION IS A
MATERIAL



INDUCEMENT FOR THE LENDER AGREEING TO ENTER INTO THIS AGREEMENT AND ACQUIRE THE
NOTE. FURTHER, THE LENDER AND THE DEBTOR HEREBY CERTIFY THAT NO REPRESENTATIVE
OR AGENT OF EITHER OF THEM, NOR THE COUNSEL OF EITHER OF THEM, HAS REPRESENTED,
EXPRESSLY OR OTHERWISE, THAT IT WOULD NOT, IN THE EVENT OF SUCH LITIGATION, SEEK
TO ENFORCE THIS WAIVER OF RIGHT TO JURY TRIAL PROVISION.

                  I.       WAIVER OF DEMAND. THE DEBTOR HEREBY EXPRESSLY WAIVES
ANY PRESENTMENT, DEMAND, PROTEST OR NOTICE IN CONNECTION WITH THIS AGREEMENT OR
THE NOTE, AS ANY MAY BE NOW OR HEREAFTER REQUIRED BY APPLICABLE LAW.

                  J.       Further Assurances. The Debtor shall promptly cure
any defects in the creation, issuance and delivery of this Agreement and the
Note. The Debtor shall, at its expense, promptly execute and deliver to the
Lender upon request, all such other and further documents, agreements, and
instruments in compliance with or accomplishment of the covenants and agreements
of the parties hereunder, or to correct any omissions herein or in the Note, or
to state more fully the obligations and agreements arising hereunder, or to
obtain any consents, all as may be reasonably necessary or appropriate in
connection therewith.

                            [signature page follows]



         IN WITNESS WHEREOF, this Agreement has been duly executed and delivered
by the undersigned as of the date set forth above.

                                    DIGILOG, INC.

                                    By: /s/ Michael Marrett
                                        ----------------------------------------
                                    Name:  Michael Marrett
                                    Title: [Executive Vice President

                                    NUMEREX CORP.

                                    By: /s/ Michael Marrett
                                        ----------------------------------------
                                    Name: Michael Marrett
                                    Title: Executive Vice President

                                    ALETHEA LIMITED PARTNERSHIP

                                    By: Jovan, Inc., its General Partner

                                        By: /s/ Stratton J. Nicolaides
                                        ----------------------------------------
                                        Name:  Stratton Nicolaides
                                        Title: Chairman