1
CONFIDENTIAL TREATMENT REQUESTED UNDER 17 C.F.R. SECTIONS 200.8(b), 200.83 AND
230.406 * INDICATES OMITTED MATERIAL THAT IS THE SUBJECT OF A CONFIDENTIAL
TREATMENT REQUEST THAT IS FILED SEPARATELY WITH THE COMMISSION


                                                                    EXHIBIT 10.4


LICENSE AGREEMENT

              MEMORANDUM OF AGREEMENT made and entered into as of the 16th day
              of July, 1996 ("Effective Date").

BY AND BETWEEN: NORTHERN TELECOM LIMITED, a corporation duly incorporated under
the laws of Canada, having an office at 2920 Matheson Boulevard East,
Mississauga, Ontario, Canada UW 4M7, on behalf of itself and its Subsidiaries
and Affiliates

(hereinafter called "Northern Telecom")

         AND:   APPLIED DIGITAL ACCESS, INC.
                a corporation duly incorporated under the laws of California and
                having an office at
                9855 Scranton Road, San Diego, California,
                U.S.A. 92121
                (hereinafter called the "Licensee")

WHEREAS Northern Telecom designs, produces and markets telecommunications
systems and is in possession of certain proprietary rights in the technology
related to such systems;

WHEREAS Licensee wishes to design, produce and market certain products or
software programs based upon certain technology of Northern Telecom; and

WHEREAS each Party is prepared to grant such licenses and enter into such
obligations, as hereinafter set forth.

NOW THEREFORE THIS AGREEMENT WITNESSETH THAT, IN CONSIDERATION OF THE MUTUAL
PROMISES HEREINAFTER SET FORTH, THE PARTIES AGREE AS FOLLOWS:


   2
ARTICLE 1
DEFINITIONS

As used herein, unless otherwise defined:

         (a) "Affiliate" shall mean a corporation or company which a Party
hereto effectively controls, directly or indirectly, other than a Subsidiary,
through the ownership or control of shares in the corporation or company;

         (b) "Authorized Products" shall mean all products which are developed
by Licensee pursuant to the licenses granted in this Agreement within the
"performance and fault management" domains as defined by the International
Telecommunications Union Telecommunication Management Network Standards Series
X.700;

         (c) "Copyrights" shall mean all copyrights owned or controlled by
Northern Telecom or its Subsidiaries or Affiliates in existence at any time in
any or all countries of the world and first existing prior to or during the term
of this Agreement;

         (d) "Enhancements" shall mean any minor extensions of the features
and/or capabilities which are contained in the Licensed Information as it exists
as of the Effective Date of this Agreement;

         (e) "Gross Sales" shall mean the proceeds paid to Licensee upon the
sublicensing of Authorized Products or of Licensed Information, as well as
engineering and installation related thereto, whether comprising a lump sum
and/or periodic payments; provided that Gross Sales shall not include (i)
separately itemized taxes, support service or maintenance fees, insurance,
interest charges on financing provided by Licensee to its customers and
transportation costs, actually paid by Licensee's customers; or (ii) any refunds
for returns.

         (f) "Intellectual Property" shall mean the aggregate of Patents,
Copyrights and Maskworks, trade secrets and know-how which relates in any way to
Licensed Information and Authorized Products;

         (g) "Joint Venture" shall mean a joint venture company which is a
cooperative business enterprise formed between Northern Telecom and other
autonomous entities to address more effectively certain mutual business
interests and opportunities.

         (h) "Licensed Information" shall mean those items of information set
forth in Schedule "A" attached hereto and forming part hereof and all source
code, object code, design documentation, Northern Telecom's customer product
documentation (including training and operations), installation and maintenance
documentation marketing materials developed for general use, test
specifications, Northern Telecom proprietary utilities and tools, command files
for software development and testing, and everything currently used by Northern
Telecom at the Effective Date to develop, modify and enhance the Licensed
Information to the extent available in accordance with Article 3 hereof.
   3
         (i) "Manufacturing Licensee" shall mean a third party entity which has
entered into an agreement with Northern Telecom to manufacture, in modified or
unmodified form, Northern Telecom products and directly or indirectly through
distributors, to sublicense and distribute Northern Telecom products under
Northern Telecom or the Manufacturing Licensee's own brand name.

         (j) "Maskworks" shall mean all rights in semiconductor topology owned
or controlled by Northern Telecom or its Subsidiaries or Affiliates similar to
those defined in the Semiconductor Chip Protection Act of 1984 (U.S.A.) in
existence at any time in any or all countries of the world and first existing
prior to or during the term of this Agreement;

         (k) "Modifications" shall mean any minor changes such as, but not
limited to, bug fixes, to the features and/or capabilities of the Licensed
Information as it exists as of the Effective Date of this Agreement;

         (1) "Patents" shall mean all patents (including utility models but
excluding design registration and design patents) owned or controlled by
Northern Telecom or its Subsidiaries or Affiliates issued at any time in any or
all countries of the world on applications having effective filing dates prior
to the expiration or termination of this Agreement, including all continuations,
continuations-in party, divisionals, reissues, additions, reexaminations and
extensions with respect to any of the foregoing;

         (m) "Subsidiary" shall mean a corporation or company in which a party
hereto effectively owns or controls, and continues to own or control directly or
indirectly, more than fifty percent (50%) of the voting stock or shares;

         (n) "Test Plan" shall mean the plan for testing set forth in the
documentation designated as such in Schedule "A" hereof.
   4
ARTICLE 2
GRANT OF RIGHTS

Northern Telecom, to the extent of its legal right so to do, hereby grants to
Licensee and its Subsidiaries and Affiliates, subject to the terms and
conditions of this Agreement, a perpetual, personal, non-transferable, exclusive
(except as set forth in this Article 2), non-assignable, indivisible, world-wide
right:

         (a) to use and modify and have modified the Licensed Information, and
any Enhancements and Modifications thereto licensed hereunder, to develop
Authorized Products;

         (b) to sublicense Authorized Products, except as expressly set forth
herein, pursuant to a valid sublicense agreement containing substantially the
terms set forth in Schedule "B";

         (c) to grant sublicenses to the Licensed Information, in object code
version only, pursuant to a valid sublicense agreement containing substantially
the terms set forth in Schedule "B";

         (d) to grant to sublicensees the right pursuant to an escrow agreement,
if the Licensee,

(i) becomes insolvent or files an assignment in bankruptcy or fails to have
dismissed any petition seeking to have it declared bankrupt within 30 days
after the filing thereof, or

(ii) after using its best efforts to support Authorized Products, ceases all
support of Authorized Products, to have access to and to use the source code
version of the Licensed Information solely for Internal use to support the
Authorized Products; and

(e) under Intellectual Property, but only to the extent necessary to enable the
exercise of the rights granted in the immediately preceding sub-paragraphs.

The aforesaid rights shall include the right to communicate to customers
purchasing the Authorized Products permitted hereunder such portions of the
Licensed Information as are reasonably needed by such customers for the use of
the Authorized Products; provided, however, that, to the extent that proprietary
information is being communicated, the recipients of the Licensed Information be
advised by Licensee in writing at the time, or before such communication, that
proprietary information is being communicated and that such information is to be
kept confidential and not used except as expressly permitted in writing and
provided that such recipients undertake such obligations of confidentiality and
restricted use in writing.

For greater certainty, Licensee shall have no right to use the Licensed
Information other than to develop Authorized Products and as set forth in the
immediately preceding paragraph. Nothing herein shall limit Northern Telecom's
right to grant licenses in the Licensed Information for activities other than
those for which the Licensee is granted an exclusive license hereunder.

For greater certainty, the exclusive rights granted hereunder shall not
prejudice Northern Telecom's patent cross-licensees or any others granted rights
in Intellectual Property which licenses do not include rights in the Licensed
Information.

Licensee shall comply with all applicable governmental legislation or
regulations imposing restrictions on the export of products.
   5
Notwithstanding anything in this Article 2, the grant of rights contained in
this Article shall be non-exclusive with respect to:

         (a) any Manufacturing Licensee or Joint Venture existing as at the date
of this Agreement;
         (b) Telrad Telecommunications & Electronic Industries Ltd. and its
existing and future sublicensees only with respect to Israel and India;
         (c) any existing or future Subsidiary of Northern Telecom;
         (d) any end user customer of Licensed Information, which may be granted
certain rights in the event that Northern Telecom fails to support products
licensed to such licensee;
         (e) BC Tel and AGT Limited, which retain rights for their own use; and
         (f) any existing sublicensee of Northern Telecom or its Subsidiaries,
Affiliates, Manufacturing

Licensees or Joint Ventures for Internal use only.

Northern Telecom agrees that it shall not grant to any party, other than the
parties described in the immediately foregoing items (a) to (f), the right to
sublicense Modifications or Enhancements to any Authorized Products.

Licensee grants to Northern Telecom and its Subsidiaries, Manufacturing
Licensees and Joint Ventures a personal, non-transferable, non-assignable,
(except as provided in this Agreement) indivisible, world-wide right to use all
Enhancements and Modifications which Licensee may develop or have developed
during the term of this Agreement in connection with the use of the Licensed
Information. Northern Telecom grants to Licensee and its Subsidiaries and
Affiliates a personal, non-transferable, non-assignable, (except as provided in
this Agreement) indivisible, world-wide right to use all Enhancements and
Modifications which Northern Telecom may develop or have developed during the
term of this Agreement in connection with the use of the Licensed Information.

Within Thirty (30) days of the end of each calendar quarter, each party shall
provide the other with a copy of all Enhancements and Modifications developed
during such preceding quarter together with all applicable documentation, or, if
applicable, written notice that no new Enhancements or Modifications have been
developed during such preceding quarter.
   6
ARTICLE 3
FURNISHING OF LICENSED INFORMATION

Northern Telecom shall, to the extent of its legal right so to do, promptly
furnish to Licensee the Licensed Information listed in Schedule "A" hereof.

Northern Telecom shall only be obliged to provide Licensed Information available
to it or its Subsidiaries, and shall not be obligated to develop or produce,
except as expressly set forth herein, any new or unavailable Licensed
Information.

Northern Telecom shall supply the Licensed Information as soon as reasonably
possible after execution of this Agreement and receipt from Licensee of the
payment set forth in the first paragraph of Article 6 and substantially complete
such supply within ninety days therefrom.

Licensed Information provided hereunder shall be deemed delivered upon delivery
to the common carrier chosen by Northern Telecom, at the relevant facility of
Northern Telecom or upon sending by Northern Telecom if such Licensed
Information is delivered by electronic means.

That portion of the Licensed Information provided by Northern Telecom to
Licensee pursuant to a prior confidentiality or non-disclosure agreement shall
be considered provided pursuant solely to this Agreement and subject only to the
terms and conditions hereof.
   7
ARTICLE 4
REVIEW OF AUTHORIZED PRODUCTS BY NORTHERN TELECOM

Licensee shall advise Northern Telecom, in writing, of each new release of
Authorized Products developed during the term of this Agreement and, at Northern
Telecom's request, provide suitable prototype and commercial versions of such
Authorized Products for a period not to exceed three (3) business days solely to
allow Northern Telecom to test such products. Authorized Products shall be
resumed to Licensee. Northern Telecom shall, test the Authorized Products on
Northern Telecom's premises and at Northern Telecom's expense in accordance with
the Test Plan.

Licensee shall provide, free of charge, such reasonable assistance of its
qualified technical personnel as may be requested by Northern Telecom to assist
in carrying out such testing.

Northern Telecom shall provide to Licensee the results of such testing, and
may, in its sole discretion, provide to Licensee comments and advice thereon.

ARTICLE 5
TECHNICAL ASSISTANCE

During the term of this Agreement, Northern Telecom shall make available to
Licensee, to the extent contemplated in the immediately following paragraphs,
upon the latter's request, technical assistance to facilitate the use of the
Licensed Information provided hereunder for the exercise of the rights granted
herein.

Technical assistance provided hereunder by Northern Telecom shall be provided as
reasonably required, under Northern Telecom's standard terms and conditions,
including Northern Telecom's then-current per diem rates therefor plus expenses.

Technical assistance provided hereunder shall be limited to that which is
reasonable under the circumstances and shall be scheduled by Northern Telecom to
serve the needs of Licensee, but not so as to inconvenience, or place excessive
demands upon, the operations of Northern Telecom, or its Subsidiaries or
Affiliates. Technical assistance shall include both consulting technical
services of Northern Telecom and visits of Northern Telecom's personnel to
Licensee's facilities.

Technical assistance provided by Northern Telecom prior to the commencement of
this Agreement and related to the subject matter hereof shall be considered
provided pursuant to this Agreement and subject only to the terms and conditions
hereof.

ARTICLE 6
PAYMENT

In consideration of the rights granted hereunder, the Licensee shall pay to
Northern Telecom the following amounts:

         (a) ** lump sum of ** upon execution of this Agreement;

         (b) a royalty ** of the Authorized Products for the period, and in
the manner, hereinafter set forth (which royalty is herein called the "Royalty")



                       * CONFIDENTIAL TREATMENT REQUESTED



   8
The Royalty shall be payable a set forth in Article 7 for a period of ** 
commencing on the Effective Date of this Agreement. Notwithstanding anything
in this Article 6, the Royalty shall not exceed an aggregate of **. The Royalty
shall accrue on the sublicensing of the Authorized Products and shall become
payable in accordance with the provisions hereof.

If the amount that a third party shall pay to Licensee for the Authorized
Products and associated engineering and installation cannot be determined at the
time that Licensee grants a license to such third party because such amount is
not separately identified, Licensee shall pay to Northern Telecom an amount
determined as set out below:

         (i)   Licensee shall establish a list price for the Authorized Product
for the particular third party customer; and

         (ii)  Licensee shall then determine a discount percentage to be applied
against such price based upon current market practice and the average discount
percentage applied to the previous five licenses granted to the Authorized
Product for which the licensee most closely approximates such license with
respect to the size and functionality of the system being licensed; provided
however, that such average shall include all prior licenses of the Authorized
Product, if five (5) or fewer of such prior licenses have been granted at that
time.

Northern Telecom shall not be under any obligation to transmit to Licensee any
Licensed Information or render any technical assistance whatsoever hereunder
until the payment of the lump sum provided in subparagraph (a) of this Article 6
has been made or to continue to provide Licensed Information or to provide
technical assistance unless payments of the Royalty or other amounts due related
to the Authorized Products are not overdue, unless such overdue payments relate
to a good faith payment dispute which has been continuing for not more than
thirty (30) days.

ARTICLE 7
RECORDS AND REMITTANCES

Licensee shall keep clear and accurate records with respect to the Authorized
Product and the Licensed Information. Northern Telecom shall have the right,
through its Internal auditing experts, to examine and audit, during normal
hours, annually (or at less frequent intervals) all such records and such other
records and accounts as may under recognized accounting practices contain
information bearing upon the amount of Royalties payable to it under this
Agreement. Prompt adjustment shall be made by the proper party to compensate for
any errors or omissions disclosed by such examination or audit. Neither such
right to examine and audit, nor the right to receive such adjustments, shall be
affected by statements to the contrary appearing on cheques or otherwise, unless
any such right is expressly waived by the party having such right. Licensee
shall furnish whatever additional information Northern Telecom may reasonably
prescribe from time to time to enable Northern Telecom to ascertain whether the
Authorized Product or Licensed Information sublicensed is subject to the payment
of Royalties hereunder and the amount payable thereon.

Within sixty (45) days following the end of each quarterly period ending on
March 31, June 30, September 30 or December 31, commencing with the quarterly
period which ends on September 30,1996 and continuing thereafter until all
Royalties payable hereunder shall have been reported and paid, Licensee shall
furnish to Northern Telecom a statement, in a form acceptable to Northern
Telecom, certified by an authorized official of Licensee, recording all
Authorized Products or Licensed Information sublicensed during such quarterly
period, the ** and the amount of Royalties payable thereon. If no Authorized
Products or Licensed Information have been sublicensed, that fact shall be
shown on such statement.



                       * CONFIDENTIAL TREATMENT REQUESTED
   9
On the last day of each quarterly period, Licensee shall pay to Northern Telecom
the Royalty applicable to all amounts received in such quarter.

All payments to be made by Licensee to Northern Telecom shall be made in United
States Dollars at Northern Telecom's address as shown in Article 13 hereof, or
at such other address as Northern Telecom shall have specified by written
notice.

Licensee shall pay all taxes imposed as a result of the existence or operation
of this Agreement including, but not restricted to, registration fees,
remittance fees, stamp taxes, sales, value added or use imposed with respect to
the granting or transfer of rights hereunder or the payment or receipt of fees
hereunder and any tax which Licensee shall be required to withhold or deduct
from fees or other payments to Northern Telecom except any tax on income imposed
on Northern Telecom.

Payments when provided for in this Agreement shall, when overdue, bear interest
at a monthly rate of one and one-half percent (1.5%) or an annual rate of
eighteen percent (18%).

ARTICLE 8
CONFIDENTIAL INFORMATION

Any information or materials (including "Licensed Information") provided by
Northern Telecom hereunder ("Confidential Information") shall remain the
property of Northern Telecom, and the Licensee shall be authorized to use such
information or materials only within the scope of the rights and licenses herein
granted.

Except as hereinafter provided, for a period of three (3) years following the
date of termination of this Agreement, Licensee shall protect Confidential
Information provided to it by use of the same care and discretion to avoid
disclosure, publication, or dissemination of such Confidential Information, as
the case may be, beyond those employees of Licensee with a need to know such
information for the purposes of this Agreement, as the Licensee employs with
similar information of its own which it does not desire to disclose, publish or
disseminate.

Information which would otherwise be classified as Confidential Information
hereunder shall not be treated as confidential, or otherwise subject to the
restrictions and obligations set forth in this Article 8, if such information:

         (a) is already in the possession of Licensee without obligation of
confidence and is so documented;
         (b)      is independently developed by Licensee and is so documented;
         (c) is or becomes publicly available without breach of this Agreement,
including Licensed Information which is made public;
         (d) is rightfully received by Licensee from a third party without
obligation of confidence; or
         (e) is released for disclosure by Northern Telecom with its written
consent.
   10
ARTICLE 9
LIABILITY



 Northern Telecom makes no representations in respect to and does not warrant
any Licensed Information furnished pursuant hereto, but shall furnish such in
good faith to the best of its knowledge and ability. Without restricting the
generality of the foregoing, Northern Telecom makes no representations or
warranties as to merchantability or fitness for a particular purpose, or as to
whether or not the use of the Licensed Information supplied hereunder may
infringe any patent or other rights of any other person.

Licensee shall indemnify and save Northern Telecom harmless from any and all
claims and liabilities for damages, losses, expenses or costs (including counsel
fees and expenses) arising out of any infringement or alleged infringement by
any modification to the Licensed Information made by or on behalf of Licensee as
well as any and all claims and liabilities arising out of any modification to
the Licensed Information made by or for Licensee.

Northern Telecom represents that to the best of its knowledge there is no
conflicting claim related to the rights granted hereunder. In the event of any
suit against Licensee or its customers for any alleged infringement of any
intellectual property right or any other right of any third party arising from
the sale or sublicense of Authorized Products by Licensee, Northern Telecom's
sole and only obligation and liability shall be to assist Licensee in defending
or otherwise dealing with such suit, at Licensee's expense, without incurring
any liability with respect to any such assistance.

In the event that either party becomes aware of any actual or suspected acts of
a third party that do or might infringe Intellectual Property rights through use
of the Licensed Technology, which infringement does or might affect any
Authorized Product (an "Infringement"), such party shall notify the other of the
Infringement and Northern Telecom may choose, but shall have no obligation, to
institute and prosecute any action or proceeding with respect to the
Infringement at the cost of Northern Telecom, and Northern Telecom shall be
entitled to any and all proceeds recovered from third parties as a result of
such enforcement. Northern Telecom agrees not to take any action inconsistent
with this Agreement in the settlement of any action.

If Northern Telecom elects not to prosecute any Infringement suit, Licensee may
do so at Licensee's own expense after notice to Licensee of that intention and
Licensee shall be entitled to any and all proceeds as a result of such
enforcement to the extent that such proceeds relate to infringement against
Authorized Products.

Licensee shall indemnify and save Northern Telecom harmless from any and all
claims and liabilities for damages, losses, expenses or costs (including counsel
fees and expenses) arising out of the furnishing or receipt of any technical
assistance pursuant hereto and hereby waives any claims that it might have or
might pretend to have against Northern Telecom, its employees and agents, as
well as those of its Subsidiaries and Affiliates, for or arising from the
provision of such assistance or information.

Notwithstanding anything else in this Article 9, Northern Telecom agrees that it
shall indemnify and save the Licensee and its Affiliates and Sublicensees
harmless with respect to any suit based on a claim that the use of the Licensed
Information or the sublicensing of the same infringes any intellectual property
right of any third party; provided that such obligation of Northern Telecom
shall apply only to the extent that Northern Telecom is indemnified by MPR
Teltech Ltd. ("MPR") pursuant to the master agreement (the "Development
Agreement") made as of December 11,1992 between MPR and Northern Telecom (as
assignee of Prism Systems Inc.) and subject to the restrictions and releases set
forth in the Development Agreement and in the DSS II development assignment
agreement made as of July 15, 1996 among MPR,
   11
ADA Canada, Inc., Northern Telecom and BC Telecom Inc. For greater certainty,
nothing in this paragraph shall render


Northern Telecom liable to Licensee in respect of a claim of infringement for
any amount in excess of the amount received by Northern Telecom from MPR in
respect of such claim of infringement.

ARTICLE 10
FORCE MAJEURE

Neither Party shall be in default or liable for any loss or damage resulting
from delays in performance or from failure to perform or comply with terms of
this Agreement due to any causes beyond its reasonable control during the
continuation of such causes, which causes include but are not limited to Acts of
God or the public enemy; riots and insurrections, war, accidents, fire, strikes
and other labour difficulties (whether or not the Party is in a position to
concede to such demands), embargoes, judicial action; lack of or inability to
obtain export permits or approvals, necessary labour, materials, energy,
components or machinery; acts of civil or military authorities.


ARTICLE 11
DURATION

This Agreement shall commence on the above mentioned Effective Date and
terminate (save with the exception of the survivorship provisions set forth in
the final paragraph of Article 12) upon completion of a period of three (3)
years following such date.

Following the expiry of this Agreement by the passage of time, Licensee may
continue to exercise the licenses granted pursuant to Article 2 as though this
Agreement had continued.


ARTICLE 12
TERMINATION

In the event either Party shall be in breach of this Agreement or fail to
perform one or more of its material obligations under this Agreement, the other
Party may, by written notice to the Party in default, require the remedy of the
breach or the performance of the obligation and, if the Party so notified fails
to remedy or perform within sixty (60) days of the forwarding of a notice so to
do, the other Party may, by written notice, terminate this Agreement.

In the event of an enforceable decision or directive declaring invalid an
essential part of this Agreement, without which this Agreement would not have
been entered into, this Agreement may, at the option of either Party, be
terminated upon the giving of notice to the other Party. Save as before set
forth, in the event that any term, clause, provision or condition of this
Agreement shall be similarly adjudged invalid for any reason whatsoever, such
invalidity shall not affect the validity or operation of any other term, clause,
provision or condition and such invalid term, clause, provision or condition
shall be deemed to have been deleted from this Agreement.

In the event that Licensee becomes majority owned or controlled by an entity
which is a direct competitor or Northern Telecom, Licensee shall forthwith
provide written notification to Northern Telecom of such change in majority
ownership or control. Within thirty (30) days of receipt of such change in
ownership or control, Northern Telecom may, in its sole discretion, elect to
terminate this Agreement and the licenses granted hereunder provided that the
acquiring entity is reasonably determined to be a direct competitor of Northern
Telecom.
   12
In the event either Party becomes involved or is the object of bankruptcy or
insolvency proceedings, or makes an assignment for the benefit of its creditors,
or is placed in receivership or liquidation, or fails to satisfy any final
judgment rendered against it within the period so permitted, then, the other
Party may, without any delay, by written notice, terminate this Agreement.

In the event of termination of this Agreement prior to the expiry of its term,
Licensee shall discontinue the exercise of the rights granted hereunder and the
use of the Licensed Information and shall pay to Northern Telecom all amounts
due hereunder.

Notwithstanding any termination hereunder, the provisions of Articles 2 and 8
related to confidentiality and non-use, and the provisions of Article 9 related
to liability shall survive the termination of this Agreement.

ARTICLE 13
NOTICES

Any and all notices or other information to be given by one of the Parties to
the other shall be deemed sufficiently given when forwarded by prepaid,
registered or certified first class air mail or by facsimile, telegram, telex or
hand delivery to the other Party at the following address:

         If to Northern Telecom:    Northern Telecom Limited
                  2920 Matheson Boulevard East
                  Mississauga, Ontario
                  Canada UW 4M7
                  Attention: Corporate Secretary


         If to Licensee:   Applied Digital Access, Inc.
                  9855 Scranton Road
                  San Diego, California
                  U.S.A. 92121
                  Attention: President

and such notices shall be deemed to have been received fifteen (15) business
days after mailing if forwarded by mail, and the following business day if
forwarded by facsimile, telegram, telex or hand.

The aforementioned address of either Party may be changed to any time by giving
fifteen (15) business days prior notice to the other Party in accordance with
the foregoing.

In the event of a generally-prevailing labour dispute or other situation which
will delay or impede the giving of notice by any such means, in either the
country of origin or of destination, the notice shall be given by such specified
mode as will be most reliable and expeditious and least affected by such dispute
or situation.
   13
ARTICLE 14
GENERAL PROVISIONS

Neither party may assign all or any portion of this Agreement without the other
party's prior written consent, such consent not to be unreasonably withheld.
Notwithstanding the foregoing, a party may assign and transfer this Agreement
and its rights and obligations hereunder to its parents, Affiliates or
Subsidiaries. In no event shall either party create any contractual relation
between any third party and the other.

The Parties recognize that the transfer of Licensed Information to or for a
country other than Canada or the United States of America may be subject to the
specific approval of the governments of such countries or various agencies
thereof.

Nothing in this Agreement shall be construed as requiring Northern Telecom to
disclose technical information, or to grant rights under licenses, or to render
any technical assistance, which would violate any confidentiality undertakings
which it has towards third persons or which would violate any present or future
law or decrees of any government or governmental office or agency, and nothing
contained herein shall require the disclosure of technical information which
would increase or impose any obligations on Northern Telecom with respect to
third parties.

Nothing contained in this Agreement shall be construed as:

         (a) requiring Northern Telecom to file any patent application, to
secure any patent or to maintain any patent in force;

         (b) constituting a warranty or representation by Northern Telecom as to
the validity or scope of any patent licensed hereunder;

         (c) constituting a warranty or representation by Northern Telecom that
any use, lease, sale or sublicense by Licensee hereunder will be free from
infringement of patents, copyrights and other intellectual property rights other
than those under which, and to the extent to which, licenses are granted
hereunder;

         (d) constituting an agreement to bring or prosecute actions or suits
against third parties for infringements;

         (e) conferring any right to use, in advertising, publicity or
otherwise, any name, trade-name or trademark, or any contraction, abbreviation
or simulation thereof;

         (f) conferring by implication, estoppel or otherwise upon Licensee any
license or other right under any patent, except the licenses and rights
expressly granted hereunder.

Except as explicitly set forth herein, nothing contained in this Agreement shall
limit, in any manner, either Party's right to discontinue or change the design
or characteristics of any of its products (including Licensed Information) at
any time without notice and without liability.
   14
The failure of either Party to give notice to the other Party of the breach or
non-fulfillment of any term, clause, provision or condition of this Agreement
shall not constitute a waiver thereof, nor shall the waiver of any breach or
non-fulfillment of any term, clause, provision or condition of this Agreement
constitute a waiver of any other breach or non-fulfillment of that or any other
term, clause, provision or condition of this Agreement.

All technical and other information provided or made available to Licensee prior
to the execution of this Agreement which would have been covered by the
definitions of Licensed Information or Confidential Information had it been
delivered pursuant to this Agreement shall be deemed to be Licensed Information
or Confidential Information, as the case may be, and to be subject to the
provisions of this Agreement.

This Agreement sets forth the entire agreement and understanding between the
Parties with respect to the subject matter addressed herein and supersedes and
cancels all previous negotiations, agreements, commitments, and writings in
respect to the subject matter hereof, and neither Party hereto shall be bound by
any term, clause, provision or condition save as expressly provided in this
Agreement or as duly set forth on or subsequent to the date hereof in writing,
signed by duly authorized officers of the Parties.

Nothing in this Agreement shall be construed as establishing or implying any
partnership between the Parties hereto, and nothing in this Agreement shall be
deemed to constitute either of the Parties hereto as the agent of the other
Party or authorize either Party to incur any expenses on behalf of the other
Party or to commit the other Party in any way whatsoever, without obtaining the
other Party's prior written consent.

The specific terms and conditions of this Agreement shall be held in confidence
by both Parties and only disclosed as may be agreed by both Parties, which
agreement shall not be unreasonably withheld by either Party. Notwithstanding
the foregoing, or paragraph (e) above, either Party may make public statements,
issue publicity or media releases, or make other disclosures, revealing the
existence of this Agreement, and the general relationship of the Parties
hereunder, without the prior approval of the other Party.

This Agreement shall be construed in accordance with and governed by the laws of
the Province of Ontario, Canada.

IN WITNESS WHEREOF, the Parties hereto have executed this Agreement on the date
first above mentioned.

         NORTHERN TELECOM LIMITED           APPLIED DIGITAL ACCESS, INC.
         Per: ___________________           Per: ________________________

         Per: ___________________           Per: ________________________
         Date:___________________           Date: _______________________


   15
                                  SCHEDULE "A"

                              LICENSED INFORMATION
   16
                                  SCHEDULE "B"

                               SUBLICENSING TERMS

sublicense agreements shall include terms and conditions substantially similar
to the following:

1.      restrict use of the Authorized Products or Licensed Information to
        object code form only;

2.      prohibit causing or permitting the reverse engineering, disassembly or
        decompilation of the Authorized Products or Licensed Information except
        to the extent permitted by law or required to obtain interoperability
        with other independently created software programs;

3.      prohibit title to the Authorized Products or Licensed Information from
        passing to the end user;

6.      disclaim Northern Telecom's liability for any damages, whether direct,
        indirect, incidental or consequential arising from the use of the
        Authorized Products or Licensed Information; and

7.      require the end user, at the termination of the sublicense, to
        discontinue use and destroy or return to Licensor the Authorized
        Products or Licensed Information, associated documentation and all
        archival or other copies of the Authorized Products or Licensed
        Information.

8.      in any sublicense to United States Government end users, include the
        following on all copies of Authorized Products distributed to United
        States Government end users;

        This software is provided with RESTRICTED RIGHTS. Use, Duplication, or
        Disclosure by the U.S. Government is subject to restrictions as set
        forth in subparagraph (c) (1) (ii) of The Rights in Technical Data and
        Computer Software clause at DFARS 252.227-7013 or subparagraphs (c) (1)
        and (2) of the Commercial Computer Software-Restricted Rights at 48 CFR
        52.227-19, or successor legislation, as applicable. Contractor/
        Manufacturer is Northern Telecom Limited, 2920 Matheson Boulevard East
        Mississauga, Ontario Canada L4W 4M7.

9.      End user shall comply with all applicable governmental legislation or
        regulations imposing restrictions on the export of products.