International OEM Agreement - Advanced Telecommunication Modules Inc. and Advanced Telecommunicatons Modules Ltd. and Com21 Inc.


                       ADVANCED TELECOMMUNICATIONS MODULES

                           INTERNATIONAL OEM AGREEMENT

This International OEM Agreement (the "Agreement") is entered into as of March
7, 1996, ("Effective Date") between Advanced Telecommunications Modules, Inc.
("ATMI"), located at 1130 East Arques Ave., Sunnyvale, CA 94086
("Manufacturer"), its parent company, Advanced Telecommunications Modules,
Limited, and Com21, Inc. ("Com21"), located at 1991 Landings Dr., Mountain View,
CA 94043 ("Purchaser").

IN CONSIDERATION OF THE MUTUAL PROMISES CONTAINED HEREIN, THE
PARTIES AGREE AS FOLLOWS:

1.      DEFINITIONS

        1.1.   "STANDARD PRODUCTS" shall mean the most current version of the
               standard products manufactured by ATMI for general end-user
               availability listed in Exhibit A attached hereto.

        1.2.   "SPECIAL PRODUCTS" shall mean the most current version of the
               non-standard products manufactured by special use by Purchaser
               listed in Exhibit A attached hereto.

        1.3.   "TERRITORY" shall mean that geographic area identified in Exhibit
               G attached hereto.

        1.4.   "END-USER" shall mean any third party which obtains a Product
               solely in order to fulfill its own internal needs.

        1.5.   "END-USER LICENSE" shall at any time during the term of
               this Agreement, mean ATMI's then standard license
               agreement pursuant to which End-Users are granted the right to
               utilize software in or provided with ATMI products.

2.      PRODUCTS AND PURCHASE COMMITMENT

        2.1.   PRODUCTS. The products covered by this Agreement shall be those
               products listed in Exhibit A attached hereto ("Standard
               Products" and "Special Products"). Products may be changed,
               abandoned or added by Manufacturer, at its sole discretion,
               provided that Manufacturer gives ninety (90) days' prior written
               notice to Purchaser. Upon written notification of Manufacturer's
               intent to change or abandon Products, Purchaser shall be granted
               an option to place a one time "End of Life" Purchase Order in
               addition to orders provided herein. "End of Life" purchase
               orders will be accepted at any time within the ninety (90) day
               notification period. If the "End of Life" purchase order is not
               sufficient to satisfy Purchaser's ongoing requirements,
               Manufacturer and Purchaser will negotiate with a third party
               escrow company to place sufficient manufacturing specifications
               to allow Purchaser to continue manufacture of the Products at
               their expense. In all cases, uses of the Products will be
               limited to those set forward in this document. Manufacturer
               shall be under no obligation to continue the production of any
               Product, except as provided herein.

        2.2.   MINIMUM PURCHASE COMMITMENT. During the term of this Agreement,
               Purchaser shall purchase minimum lot quantities of Products as
               set forth in Exhibit A attached hereto ("Minimum Purchase
               Commitment").

3.      LIMITATIONS ON PURCHASER'S RIGHTS TO THE PRODUCTS

        3.1.   OEM CERTIFICATION. Purchaser certifies that each and every
               Product to be purchased under this Agreement will be purchased on
               its behalf as an original equipment manufacturer and that each
               and every Product will be incorporated by Purchaser or its
               customers into another system that Purchaser assembles, for sale
               or lease, in the regular course of Purchaser's business.
               Purchaser further certifies that the system into which each and
               every Product is incorporated will include the addition of
               hardware and/or software supplied by Purchaser which, by an
               objective examination of such






               factors as cost, product features, and pricing, represent a
               significant enhancement and transformation of the Products (with
               regard to both value and function) and result in a system
               substantially different from any of Manufacturer's systems.
               Purchaser agrees that Products intended for other purposes shall
               not be purchased under this Agreement. Upon Manufacturer's
               request, Purchaser shall furnish to Manufacturer evidence of
               compliance with the provisions of this Subsection 3.1. Purchaser
               acknowledges and agrees that its initial and continuing
               qualification under this Subsection 3.1. is within the sole
               discretion of Manufacturer.

        3.2.   PURCHASE OF PRODUCTS SUBJECT TO SOFTWARE LICENSE AND OTHER
               RESTRICTIONS. The sale of each Product to Purchaser and the
               transfer of title for each purchased Product to Purchaser shall
               not include a sale of any software, computer programs, source
               codes, object codes, listings or related materials in
               machine-readable or printed form (including, firmware and all
               types of media), or any updates and modifications thereto that
               are included (collectively, "Software") or a transfer of Software
               title to Purchaser. Instead, the sale of each Product shall
               include a fully paid license for Purchaser to transfer the
               Software to its customers upon execution of a Software license by
               Purchaser's customers in accordance with the terms of Subsection
               6.1. below. Manufacturer shall retain full title to the Software
               and all copies thereof and Purchaser and its customers may use
               the Software only in accordance with the provisions of their
               executed Software licenses. Neither Purchaser nor its customers
               shall have any access to or rights in the Software source codes.
               Neither Purchaser nor its customers shall have the right to copy,
               modify or remanufacture any Product or part thereof.

4.      TERMS IS OF PURCHASE OF PRODUCTS BY PURCHASER

        4.1.   TERMS AND CONDITIONS. All purchases of Products by Purchaser from
               Manufacturer during the term of this Agreement shall be subject
               to the terms and conditions of this Agreement.

        4.2.   PRICES. All prices are F.O.B. (as defined in Section 2319 of the
               California Uniform Commercial Code) Manufacturer's plant
               currently located at the address listed in Exhibit H or the point
               of arrival in the United States. Provided that Purchaser fulfills
               its Minimum Purchase Commitment in Exhibit A attached hereto, the
               purchase price to Purchaser for each of the Products ("Purchase
               Price") shall be a fixed percentage of Manufacturer's list price
               for that Product; the percentage for each Product is as set forth
               in Exhibit B attached hereto, and the current list prices for the
               Products are as set forth in Exhibit C attached hereto. The
               Purchase Price to Purchaser for repair parts for the Products
               shall be as set forth in Exhibit D attached hereto. Manufacturer
               has the right at any time to revise the prices in Exhibits C and
               D with thirty (30) days' advance written notice to Purchaser, but
               such prices shall not be greater than those sold to another
               customer in similar volumes. Such revisions shall only apply to
               all orders received after the effective date of revision. Price
               increases shall not affect unfulfilled purchase orders accepted
               by Manufacturer prior to the effective date of the price
               increase. Price decreases shall apply to pending purchase orders
               accepted by Manufacturer prior to the effective date of the
               decrease but not yet shipped.

        4.3.   BILLBACK PROVISIONS. Purchaser's Purchase Price for each Product
               is based on the Minimum Purchase Commitment set forth in Exhibit
               B attached hereto. If Purchaser fails to purchase at least the
               minimum number of Products specified in Exhibit B for a given
               time period, then Manufacturer shall invoice Purchaser for the
               difference between Purchaser's Purchase Price and Manufacturer's
               standard discounted price for the quantity of Products actually
               purchased, and the full amount shall be due and payable to
               Manufacturer within thirty (30) days after the invoice date. The
               adjusted Purchase Price shall continue in effect for a given
               Product until Purchaser fails in a given time period to purchase
               the number of Products necessary for the adjusted Purchase Price,
               at which time the Purchase Price shall be further adjusted in
               accordance with the foregoing, procedure or until Purchaser again
               purchases the minimum number of the Product specified in Exhibit
               B in which case the Purchase Price shall apply.

        4.4.   TAXES. Purchaser's Purchase Price does not include any federal,
               state or local taxes that may be applicable to the Products. When
               Manufacturer has the legal obligation to collect such taxes, the
               appropriate amount shall be added to Purchaser's invoice and paid
               by Purchaser unless Purchaser






               provides Manufacturer with a valid tax exemption certificate
               authorized by the appropriate taxing authority.

        4.5.   ORDER AND ACCEPTANCE. All orders for Products submitted by
               Purchaser shall be initiated by written purchase orders sent to
               Manufacturer and requesting a delivery date during the term of
               this Agreement; provided, however, that an order may initially be
               placed orally or by telex if a confirmational written purchase
               order is received by Manufacturer within five (5) days after said
               oral or telex order. To facilitate Manufacturer's production
               scheduling Purchaser shall submit non- binding forecasts to
               Manufacturer ninety (90) days prior to the requested month of
               delivery. Purchaser shall submit binding purchase orders to
               Manufacturer at least thirty (30) days prior to the first day of
               the requested month of delivery. No order shall be binding upon
               Manufacturer until accepted by Manufacturer in writing, and
               Manufacturer shall have no liability to Purchaser with respect to
               purchase orders that are not accepted. Manufacturer shall use its
               reasonable best efforts to notify Purchaser of the acceptance or
               rejection of an order and of the assigned delivery date for
               accepted orders within fifteen (15) days after receipt of the
               purchase order. No partial shipment of an order shall constitute
               the acceptance of the entire order. absent the written acceptance
               of such entire order. Manufacturer shall use its reasonable best
               efforts to deliver Products at the times specified either in its
               quotation or in its written acceptance of Purchaser's purchase
               orders.

        4.6.   TERMS OF PURCHASE ORDERS. Purchaser's purchase orders submitted
               to Manufacturer from time to time with respect to Products to be
               purchased hereunder shall be governed by the terms of this
               Agreement, and nothing contained in any such purchase order shall
               in any way modify such terms of purchase or add any additional
               terms or conditions.

        4.7.   INITIAL ORDER. Upon execution of this Agreement, Purchaser shall
               deliver to Manufacturer a written purchase order for the
               quantities of Products shown in Exhibit E attached hereto. The
               order shall be non-cancelable and shall be shipped to Purchaser
               based on Purchaser's delivery dates accepted by Manufacturer
               based on its production schedule and receipt of an export
               license.

        4.8.   CHANGE ORDERS. Purchaser may utilize written change orders
               without penalty for orders that have not vet been accepted by
               Manufacturer. For orders that have been accepted by Manufacturer
               but have not yet been shipped (excluding the initial order under
               Subsection 4.7. above), Purchaser may utilize written change
               orders subject to the following conditions:

               4.8.1.        Purchaser may delay delivery of any accepted order,
                             provided that the rescheduled delivery date occurs
                             during the term of this Agreement and provided
                             further that Purchaser shall pay a rescheduling fee
                             equal to [*] of the Purchase Price (net of freight,
                             taxes, and other charges) of the rescheduled
                             Products if Purchaser's change order is received by
                             Manufacturer less than thirty (30) days before the
                             assigned delivery date. Unless Manufacturer
                             otherwise agrees, no change order shall be
                             effective unless accompanied by the rescheduling
                             fee. if any, required by this Subsection 4.8.1.

               4.8.2.        Purchaser may cancel any order that has been
                             accepted by Manufacturer, provided that, if the
                             written change order is received by Manufacturer
                             less than thirty (30) days before the assigned
                             delivery date or if the written change order
                             cancels an order that has been previously
                             rescheduled under Subsection 4.8.1. above, then
                             Purchaser shall pay a cancellation charge equal to
                             fifteen percent (15%) of the net Purchase Price of
                             the canceled Products.




        NOTICE PRIOR TO DELIVERY DATE              RESCHEDULING CHARGE          CANCELLATION CHARGE
        -----------------------------              -------------------          -------------------
                                                                          
        Greater than 90 days                               [*]                         [*]
        31-90 days (forecasting period)                    [*]                         [*]
        0-30 days (confirmed orders)                       [*]                         [*]



        4.9.   PAYMENT. Manufacturer shall ship Products FOB from their
               manufacturing facility and shall


*Certain information on this page has been omitted and filed separately with the
 Commission. Confidential treatment has been requested with respect to the
 omitted portions.





               invoice upon shipment in U.S. dollars. Full payment of
               Purchaser's Purchase Price for the Products and spare parts
               (including any freight, taxes or other applicable costs initially
               paid by Manufacturer but to be home by Purchaser) shall be made
               by Purchaser to Manufacturer thirty (30) days from the date of
               the invoice. Payment shall be in U.S. dollars. All exchange,
               interest, banking, collection, and other charges shall be at
               Purchaser's expense. At such time as Manufacturer may grant a
               line of credit to Purchaser, payment terms shall be net thirty
               (30) days after date of invoice, and payment shall be made by
               wire transfer, check or other instrument approved by
               Manufacturer. Any invoiced amount not paid when due shall be
               subject to a service charge of one and one-half percent (1.5%)
               per month. Purchaser shall pay all of Manufacturer's costs and
               expenses (including reasonable attorneys' fees) to enforce and
               preserve Manufacturer's rights under this Subsection 4.9.

        4.10.  SHIPPING. All Products delivered pursuant to the terms of this
               Agreement shall be suitably packed depending on the method of
               freight shipment in Manufacturer's standard shipping cartons,
               marked for shipment at Purchaser's address set forth above, and
               delivered to Purchaser or its carrier agent F.O.B. Manufacturer's
               manufacturing plant, at which time (subject to Subsection 4.13.
               below) title to such Products and risk of loss shall pass to
               Purchaser. Unless otherwise instructed in writing by Purchaser,
               Manufacturer shall select the carrier. All freight, insurance,
               and other shipping expenses, as well as any special packing
               expense, shall be paid by Purchaser from the FOB point. Purchaser
               shall also bear all applicable taxes, duties, and similar charges
               that may be assessed against the Products after delivery to the
               carrier at Manufacturer's plant.

        4.11.  REJECTION OF PRODUCTS. Purchaser shall inspect all Products
               promptly upon receipt thereof and may reject any Product that
               fails in any material way to meet the specifications set forth in
               Manufacturer's current brochure and specifications for that
               Product. Any Product not properly rejected within thirty (30)
               days after receipt of that Product by Purchaser ("Rejection
               Period") shall be deemed accepted. If any unit of a Product is
               shipped by Purchaser to its customer prior to the expiration of
               the Rejection Period, then that unit shall be deemed accepted
               upon shipment by Purchaser. To reject a Product, Purchaser shall,
               within the Rejection Period, notify Manufacturer in writing or by
               telex of its rejection and request a Return Material
               Authorization ("RMA") number. Manufacturer shall use its best
               efforts to provide the RMA number in writing or by telex to
               Purchaser within three (3) business days after receipt of the
               request. Within ten (10) days after receipt of the RMA number,
               Purchaser shall return to Manufacturer the rejected Product,
               freight prepaid, in its original shipping carton with the RMA
               number displayed on the outside of the carton. Provided that
               Manufacturer has complied with its obligations in this Subsection
               4.11., Manufacturer reserves the right to refuse to accept any
               rejected Products that do not bear an RMA number on the outside
               of the carton. As promptly as possible but no later than thirty
               (30) working days after receipt by Manufacturer of properly
               rejected Products, Manufacturer shall, at its option and expense,
               either repair or replace the Products. Manufacturer shall pay the
               shipping charges back to Purchaser for properly rejected
               Products; otherwise, Purchaser shall be responsible for the
               shipping charges.

        4.12.  RETURN OF PRODUCTS AFTER REJECTION PERIOD. Unless a Product is
               returned in accordance with the provisions of Manufacturer's
               standard warranty for the Product described in Subsection 5.1.
               below, after the Rejection Period Purchaser may not return a
               Product to Manufacturer for any reason without Manufacturer's
               prior written consent. For any Product for which Manufacturer
               gives such consent, Manufacturer shall charge Purchaser a
               restocking fee equal to fifteen percent (15%) of Purchaser's
               Purchase Price for that Product and shall credit the balance of
               the Purchase Price to Purchaser's account. Purchaser shall be
               responsible for all shipping charges.

        5.     WARRANTY TO PURCHASER

        5.1.   STANDARD LIMITED WARRANTY. Manufacturer grants to Purchaser
               Manufacturer's standard limited warranty for the Products,
               including the limitations set forth in Subsections 5.2. and 5.3.
               below. Specifically, Manufacturer warrants that the Product
               hardware as delivered (except consumable items, such as fuses)
               conform to published specifications and are free from defects in
               materials and workmanship under normal use and service for the
               period set forth in the applicable Product






               documentation. All Product warranty periods are Product specific
               and may vary by Product. The End-User warranty specifically
               disclaims all other warranties relating to the Products,
               including all warranties with respect to the performance of the
               Products. This warranty is contingent upon proper use of a
               Product in the application for which it was intended and does not
               cover Products that were modified without Manufacturer's approval
               or that were subjected by the customer to unusual physical or
               electrical stress. The Manufacturer's Standard Limited Warranty
               including terms, conditions, and warranty periods in included in
               Exhibit I attached hereto.

        5.2.   NO OTHER WARRANTY. EXCEPT FOR THE EXPRESS WARRANTY SET FORTH
               ABOVE, MANUFACTURER GRANTS NO OTHER WARRANTIES, EXPRESS OR
               IMPLIED, BY STATUTE OR OTHERWISE, REGARDING THE PRODUCTS, THEIR
               FITNESS FOR ANY PURPOSE, THEIR QUALITY, THEIR MERCHANTABILITY, OR
               OTHERWISE. MANUFACTURER GRANTS NO WARRANTIES TO PURCHASER'S
               CUSTOMERS.

        5.3.   LIMITATION OF LIABILITY. MANUFACTURER'S LIABILITY UNDER THE
               WARRANTY SHALL BE LIMITED TO A REFUND OF PURCHASER'S PURCHASE
               PRICE. IN NO EVENT SHALL MANUFACTURER BE LIABLE FOR THE COST OF
               PROCUREMENT OF SUBSTITUTE GOODS BY PURCHASER OR PURCHASER'S
               CUSTOMER OR FOR ANY SPECIAL, CONSEQUENTIAL OR INCIDENTAL DAMAGES
               FOR BREACH OF WARRANTY.

        6.     SOFTWARE LICENSING AND SERVICES

        6.1.   LICENSE TO PURCHASER. Manufacturer hereby grants to Purchaser an
               exclusive (except for usage rights reserved to Manufacturer),
               royalty-free, fully paid license to use, distribute, demonstrate
               and sublicense the object code of the Software in the Territory
               specified in Exhibit H attached hereto in carrying out
               Purchaser's obligations under the provisions of this Agreement.
               The license shall terminate on the termination of this Agreement
               for any reason.

        6.2    SUBLICENSING. Purchaser shall require each of its customers to
               execute a software End-User License for each Product purchased,
               in the form attached hereto as Exhibit F, as a specific condition
               to the purchase of that Product. Purchaser shall maintain a file
               of these such license agreements for Manufacturer's review. The
               End-User License fee for each Product is included in Purchaser's
               Purchase Price for the Product.

        6.3.   SERVICES. To each licensee of the Software, Manufacturer shall
               provide the software maintenance services that are set forth in
               the License.

        7.     IMPORT AND EXPORT REQUIREMENTS

               Purchaser shall, at its own expense, pay all import and export
               licenses and permits, pay customs charges and duty fees, and take
               all other actions required to accomplish the export and import of
               the Products purchased by Purchaser from the point of delivery
               into the United States. Purchaser understands that Manufacturer
               is subject to regulation by agencies of the U.S. government,
               including the U.S., Department of Commerce, which prohibit export
               or diversion of certain technical products to certain countries.
               Purchaser warrants that it will comply in all respects with the
               export and reexport restrictions set forth in the export license
               for every Product shipped to Purchaser.

        8.     TERMS AND TERMINATION

        8.1.   TERM. This Agreement shall continue in force for a fixed term of
               five (5) years from the date hereof unless terminated earlier
               under the provisions of this Section 8. At the end of the fixed
               term, this Agreement shall terminate automatically without notice
               unless prior to that time the term of the Agreement is extended
               by mutual written consent of the parties.

        8.2.   TERMINATION FOR CONVENIENCE. This Agreement may be canceled by
               either party for any reason or no reason, whether or not extended
               beyond the initial term, by giving the other party written


*Certain information on this page has been omitted and filed separately with the
 Commission. Confidential treatment has been requested with respect to the
 omitted portions.





               notice one hundred eighty (180) in advance.

        8.3.   TERMINATION FOR CAUSE. Except as set forth in Subsection 8.4.
               below, if either party defaults in the performance of any
               provision of this Agreement, then the non-defaulting party may
               give written notice to the defaulting party that if the default
               is not cured within thirty (30) days the Agreement will be
               terminated. If the non-defaulting party gives such notice and the
               default is not cured during the thirty-day period, then the
               Agreement shall automatically terminate at the end of that
               period.

        8.4.   TERMINATION FOR FAILURE TO PURCHASE MINIMUM COMMITMENT. If
               Purchaser during the term of the agreement to purchase the
               minimum number of Products set forth in Subsection 2.2. above,
               then Manufacturer may terminate this Agreement effective upon
               delivery of a written notice to Purchaser, which is not cured in
               sixty (60) days.

        8.5.   TERMINATION FOR INSOLVENCY. This Agreement shall terminate,
               without notice, (i) upon the institution by or against Purchaser
               of insolvency, receivership or bankruptcy proceedings or any
               other proceedings for the settlement of Purchaser's debts, (ii)
               upon Purchaser's making an assignment for the benefit of
               creditors, or (iii) upon Purchaser's dissolution or ceasing to do
               business.

        8.6.   FULFILLMENT OF ORDERS UPON TERMINATION. Upon termination of this
               Agreement for other than Purchaser's breach, Manufacturer shall
               continue to fulfill, subject to the terms of Section 4 above, all
               orders accepted by Manufacturer prior to the date of termination.

        8.7.   LIMITATION ON LIABILITY. In the event of termination by either
               party in accordance with any of the provisions of this Agreement,
               neither party shall be liable to the other, because of such
               termination, for compensation, reimbursement or damages on
               account of the loss of prospective profits or anticipated sales
               or on account of expenditures, inventory, investments, leases or
               commitments in connection with the business or goodwill of
               Manufacturer or Purchaser. Termination shall not, however,
               relieve either party of obligations incurred prior to the
               termination.

        8.8.   SURVIVAL OF CERTAIN TERMS. The provisions of Sections 3.2., 4.3.,
               4.9., 4.13., 5, 7, 8, 9, 10, 11, 12, and 13 shall survive the
               termination of this Agreement for any reason. All Licenses
               executed under the provisions of Subsection 6.2. above prior to
               termination of this Agreement shall survive the termination of
               this Agreement for any reason. All other rights and obligations
               of the parties shall cease upon termination of this Agreement.

        9.     LIMITED LIABILITY TO PURCHASER AND OTHERS

               MANUFACTURER'S LIABILITY ARISING OUT OF THIS AGREEMENT AND/OR
               SALE OF THE PRODUCTS SHALL BE LIMITED TO THE AMOUNT PAID BY
               PURCHASER OR THE AMOUNT RECEIVED BY MANUFACTURER FOR THE
               PRODUCTS. IN NO EVENT SHALL MANUFACTURER BE LIABLE FOR COSTS OF
               PROCUREMENT OF SUBSTITUTE GOODS BY ANYONE. IN NO EVENT SHALL ANY
               PARTY BE LIABLE TO THE OTHER OR ANY OTHER ENTITY FOR ANY SPECIAL,
               CONSEQUENTIAL OR OTHER DAMAGES, HOWEVER CAUSED, WHETHER FOR
               BREACH OF CONTRACT, NEGLIGENCE OR OTHERWISE, AND WHETHER OR NOT
               SUCH PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

        10.    PROPERTY RIGHTS AND CONFIDENTIALITY

        10.1.  PROPERTY RIGHTS. Purchaser agrees that Manufacturer owns all
               right, title, and interest in the product lines that include the
               Products and in all of Manufacturer's patents, trademarks, trade
               names, inventions, copyrights, know-how, and trade secrets
               relating to the design, manufacture, operation or service of the
               Products.

        10.2.  SALE CONVEYS NO RIGHT TO MANUFACTURE OR COPY. The Products are
               offered for sale and are sold


*Certain information on this page has been omitted and filed separately with the
 Commission. Confidential treatment has been requested with respect to the
 omitted portions.





               by Manufacturer subject in every case to the condition that such
               sale does not convey any license. expressly or by implication, to
               manufacture, duplicate or otherwise copy or reproduce any of the
               Products except as provided by agreement between ATML and Com21
               regarding, a Hardware and Software Technology License. Purchaser
               shall take appropriate steps with its customers, as Manufacturer
               may request, to inform them of and assure compliance with the
               restrictions contained in this Subsection 10.2.

        10.3.  CONFIDENTIALITY. Purchaser acknowledges that by reason of its
               relationship to Manufacturer hereunder it may have access to
               certain information and materials concerning Manufacturer's
               business, plans, customers, technology, and products that are
               confidential and of substantial value to Manufacturer, which
               value would be impaired if such information were disclosed to
               third parties. Purchaser agrees that it will not use in any way
               for its own account or the account of any third party, nor
               disclose to any third party, any such confidential information
               revealed to it by Manufacturer. Purchaser shall take every
               reasonable precaution to protect the confidentiality of such
               information. Upon request by Purchaser, Manufacturer shall advise
               whether or not it considers any particular information or
               materials to be confidential. Purchaser shall not publish any
               technical description of the Products beyond the description
               published by Manufacturer. In the event of termination of this
               Agreement, there shall be no use or disclosure by Purchaser of
               any confidential information of Manufacturer, and Purchaser shall
               not manufacture or have manufactured any devices, components or
               assemblies utilizing any of Manufacturer's confidential
               information. Purchaser's obligations shall not apply to
               information that: (i) is generally known to the public, or (ii)
               was in Purchaser's possession or known by it prior to receipt
               from Manufacturer, or (iii) was rightfully disclosed to Purchaser
               by a third party without restriction, or (iv) was independently
               developed by Purchaser without use of any confidential
               information of Manufacturer.

        11.    TRADEMARKS AND TRADE NAMES

               11.1 USE. During the term of this Agreement, Purchaser shall have
               the right to indicate to the public that its systems contain
               Manufacturer's Products and to designate such Products under the
               trademarks, marks, and trade names that Manufacturer may adopt
               from time to time ("Manufacturer's Trademarks"). Purchaser shall
               not alter or remove any Manufacturer's Trademark applied to the
               Products at the factory. Except as set forth in this Section 11,
               nothing contained in this Agreement shall grant to Purchaser any
               right, title or interest in Manufacturer's Trademarks. At no time
               during or after the term of this Agreement shall Purchaser
               challenge or assist others to challenge Manufacturer's Trademarks
               or the registration thereof or attempt to register any
               trademarks, marks or trade names confusingly similar to those of
               Manufacturer.

        11.2.  APPROVAL OF REPRESENTATIONS. All representations of
               Manufacturer's Trademarks that Purchaser intends to use shall
               first be submitted to Manufacturer for approval (which shall not
               be unreasonably withheld) of design, color, and other details or
               shall be exact copies of those used by Manufacturer.

        12.    PATENT, COPYRIGHT, AND TRADEMARK INDEMNITY

        12.1.  INDEMNIFICATION. Purchaser agrees that Manufacturer has the right
               to defend, or at its option to settle, and Manufacturer agrees,
               at its own expense, to defend or at its option to settle, any
               claim, suit or proceeding brought against Purchaser or its
               customer on the issue of infringement of any United States
               patent, copyright or trademark by the Products sold hereunder or
               the use thereof, subject to the limitations hereinafter set
               forth. Manufacturer shall have sole control of any such action or
               settlement negotiations, and Manufacturer agrees to pay, subject
               to the limitations hereinafter set forth, any final judgment or
               settlement entered against Purchaser or its customer on such
               issue in any such suit or proceeding defended by Manufacturer.
               Purchaser agrees that Manufacturer at its sole option shall be
               relieved of the foregoing obligations unless Purchaser or its
               customer notifies Manufacturer promptly in writing of such claim,
               suit or proceeding and gives Manufacturer authority to proceed as
               contemplated herein, and, at Manufacturer's expense, gives
               Manufacturer proper and full information and assistance to settle
               and/or defend any such claim, suit or proceeding. If the
               Products, or any part thereof, are, or in the opinion of
               Manufacturer may






               become, the subject of any claim, suit or proceeding for
               infringement of any United States patent, copyright or trademark,
               or if it is adjudicatively determined that the Products, or any
               part thereof, infringe any United States patent, copyright or
               trademark, or if the sale or use of the Products, or any part
               thereof, is, as a result, enjoined, then Manufacturer may, at its
               option and expense either: (i) procure for Purchaser and its
               customers the right under Such patent, copyright or trademark to
               sell or use, as appropriate, the Products or such part thereof;
               or (ii) replace the Products, or part thereof, with other
               suitable Products or parts of equivalent performance or
               functionality; or (iii) suitably modify the Products, or part
               thereof while maintaining equivalent performance and
               functionality; or (iv) if the use of the Products, or part
               thereof, evented by injunction, remove the Products, or part
               thereof, and refund the aggregate payments paid therefor by
               Purchaser, less a reasonable sum for use and damage. Manufacturer
               shall not be liable for any costs or expenses incurred without
               its prior written authorization.

        12.2.  LIMITATION. Notwithstanding the provisions of Subsection 12.1.
               above, Manufacturer assumes no liability for (i) infringements
               covering completed equipment or any assembly, circuit,
               combination, method or process in which any of the Products may
               be used but not covering the Products when used alone; (ii)
               trademark infringements involving any marking or branding not
               applied by Manufacturer or involving any marking or branding
               applied at the request of Purchaser; or (iii) infringements
               involving the modification or servicing of the Products, or any
               part thereof, unless such modification or servicing was done by
               Manufacturer.

        12.3.  ENTIRE LIABILITY. The foregoing provisions of this Section 12
               state the entire liability and obligations of Manufacturer and
               the exclusive remedy of Purchaser and its customers, with respect
               to any alleged infringement of patents, copyrights, trademarks or
               other intellectual property rights by the Products or any part
               thereof.

        13.    GENERAL PROVISIONS

        13.1.  INDEPENDENT CONTRACTORS. The relationship of Manufacturer and
               Purchaser established by this Agreement is that of independent
               contractors and nothing contained in this Agreement shall be
               construed to (i) give either party the power to direct and
               control the day-to-day activities of the other, (ii) constitute
               the parties as partners, joint venturers, co-owners or otherwise
               as participants in a joint or common undertaking, or (iii) allow
               Purchaser to create or assume any obligation on behalf of
               Manufacturer for any purpose whatsoever. All financial
               obligations associated with Purchaser's business are the sole
               responsibility of the Purchaser. All sales and other agreements
               between Purchaser and its customers are Purchaser's exclusive
               responsibility and shall have no effect on Purchaser's
               obligations under this Agreement. Purchaser shall be solely
               responsible for, and shall indemnify and hold Manufacturer free
               and harmless from, any and all claims, damages or lawsuits
               (including, Manufacturer attorneys' fees) arising out of the acts
               of Purchaser, its employees or its agents.

        13.2.  GOVERNING LAW AND JURISDICTION. This Agreement shall be covered
               by and construed under the laws of the State of California,
               U.S.A., except that perfection of the title reserved by
               Manufacturer in Subsection 4.13. above shall be governed by the
               laws of Purchaser's jurisdiction. The federal and state courts
               within the State of California, U.S.A., shall have exclusive
               jurisdiction to adjudicate any dispute arising out of this
               Agreement. Purchaser hereby expressly consents to (1) the
               personal jurisdiction of the federal and state courts within
               California, (ii) service of process being effected upon it by
               registered mail sent to the address set forth at the beginning of
               this Agreement, and (iii) the uncontested enforcement of a final
               judgment from such court in any other jurisdiction wherein
               Purchaser or any of its assets are present.

        13.3.  ENTIRE AGREEMENT. This Agreement sets forth the entire agreement
               and understanding of the parties relating to the subject matter
               herein and merges all prior discussions between them. No
               modification of or amendment to this Agreement, nor any waiver of
               any rights under this Agreement, shall be effective unless in
               writing signed by the party to be charged.

        13.4.  NOTICES. Any notice required or permitted by this Agreement shall
               be in writing and shall be sent






               by prepaid registered or certified mail, return receipt
               requested, addressed to the other party at the address shown at
               the beginning of this Agreement or at such other address for
               which such party gives notice hereunder. Such notice shall be
               deemed to have been given three (3) days after deposit in the
               mail.

        13.5.  FORCE MAJEURE. Nonperformance of either party shall be excused to
               the extent that performance is rendered impossible by strike,
               fire, flood, governmental acts or orders or restrictions, failure
               of suppliers, or any other reason where failure to perform is
               beyond the reasonable control of and is not caused by the
               negligence of the nonperforming party.

        13.6.  NONASSIGNABILITY AND BINDING EFFECT. A mutually agreed
               consideration for Manufacturer's entering into this Agreement is
               the reputation, business standing, and goodwill already honored
               and enjoyed by Purchaser under its present ownership, and,
               accordingly, Purchaser agrees that its rights and obligations
               under this Agreement may not be transferred or assigned directly
               or indirectly without the prior written consent of Manufacturer
               provided that purchaser's assignment to an acquiror of all or
               substantially all of Purchaser's stock, assets or business shall
               not require Manufacturer's consent. Subject to the foregoing
               sentence, this Agreement shall be binding upon and inure to the
               benefit of the parties hereto and their successors and assigns.

        13.7.  LEGAL EXPENSES. The prevailing, party in any legal action brought
               by one party against the other and arising out of this Agreement
               shall be entitled, in addition to any other rights and remedies
               it may have, to reimbursement for its expenses, including court
               costs and reasonable attorneys' fees.

        13.8.  COUNTERPARTS. This 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 instrument.

Advanced Telecommunications Modules, Inc.          Com21, Inc.

By:                                                By:

Title:                                             Title:








                                    EXHIBIT A
               PRODUCT DESCRIPTION AND MINIMUM PURCHASE COMMITMENT


STANDARD PRODUCTS

PRODUCTION                   DESCRIPTION

VM1000                Virata Switch Base
VM2100                4XATM25 Switch Adapter
VM2200                2XATN155 UPT-5 Switch Adapter
VM3200                2XATMI55 MMF Switch Adapter
VM8100                Ethernet Switch Adapter

SPECIAL PRODUCTS

PRODUCT NO.           DESCRIPTION

VM1000SP              Virata Switch Base Motherboard






MINIMUM PURCHASE COMMITMENT

PRODUCT NO.           MINIMUM PURCHASE

VM1000                [*]
VM1000SP              [*]                                         
                                                               
VM2100                [*]                                         
VM2200                [*]                                         
VM3200                [*]                                         
VM8100                [*]                                         




*Certain information on this page has been omitted and filed separately with the
 Commission. Confidential treatment has been requested with respect to the
 omitted portions.





                                    EXHIBIT B
                             PRODUCT PURCHASE PRICE

STANDARD PRODUCTS



PRODUCT NO.           QUANTITY                               PURCHASER'S DISCOUNT OFF LIST PRICE
-----------           --------                               -----------------------------------
                      (OVER 360 DAY PERIOD)
                                                           
VM1000                [*]                                       [*]       
                                                                [*]       
VM2100                [*]                                       [*]       
                                                                [*]       
VM2200                [*]                                       [*]       
                                                                [*]       
VM3200                [*]                                       [*]       
                                                                [*]       
VM8100                [*]                                       [*]       
                                                                       


SPECIAL PRODUCTS



PRODUCT NO.     QUANTITY                      PURCHASER'S DISCOUNT
-----------     --------                      --------------------
                                        
VM1000SP        [*]                           [*]                                                                      
                                                                                          
                                                                                          
                                                                                          




*Certain information on this page has been omitted and filed separately with the
 Commission. Confidential treatment has been requested with respect to the
 omitted portions.




                                    EXHIBIT C
                       MANUFACTURER'S CURRENT LIST PRICES




PRODUCT NO.           DESCRIPTION                               LIST PRICE
-----------           -----------                               ----------
                                                                 
VL1000                Virata Link PC ISA, Adapter ATM25         $[*]
VL2000                Virata Link PC PCI Adapter, ATM 25        $[*]
VM1000                Virata Switch Base                        $[*]
VM2100                4XATM25 Switch Adapter                    $[*]
VM2200                2XATMI55 UPT-5 Switch Adapter             $[*]
VM3200                2XATM155 MMF Switch Adapter               $[*]
VM8100                Ethernet Switch Adapter                   $[*]
VS3200                Virata Store 8 GB 155mbs MNM Server       $[*]



*Certain information on this page has been omitted and filed separately with the
 Commission. Confidential treatment has been requested with respect to the
 omitted portions.




                                    EXHIBIT D
                       SPARE PARTS LIST AND PRICE SCHEDULE




DESCRIPTION               QUANTITY                         LIST PRICE
-----------               --------                         ----------
                                                          (PER DEVICE)
                                                    
Quark Chip            [*]                                     [*]
                      [*]                                     [*]
Gluon Chip            [*]                                     [*]
                      [*]                                     [*]



*Certain information on this page has been omitted and filed separately with the
 Commission. Confidential treatment has been requested with respect to the
 omitted portions.




                                    EXHIBIT E
                                  INITIAL ORDER

Upon execution of this Agreement, Purchaser shall deliver to Manufacturer a
written, noncancelable purchase order for the following quantities of Products:



Product                           Quantity
-------                           --------
                               
VM1000 - Virata Switch Base         [*]
Quark Chip                          [*]
Gluon Chip                          [*]




*Certain information on this page has been omitted and filed separately with the
 Commission. Confidential treatment has been requested with respect to the
 omitted portions.




                                    EXHIBIT F
                                SOFTWARE LICENSE

                   ADVANCED TELECOMMUNICATIONS MODULES LIMITED
                            END-USER SOFTWARE LICENSE
                                  REVISION 1.0

PLEASE READ THIS LICENSE CAREFULLY BEFORE OPENING THE PACKAGE OR USING THE
SOFTWARE. BY OPENING THE PACKAGE OR USING THE SOFTWARE, YOU ARE AGREEING TO BE
BOUND BY THE TERMS OF THIS LICENSE. IF YOU DO NOT AGREE TO THE TERMS OF THIS
LICENSE, PROMPTLY RETURN THE UNUSED SOFTWARE TO THE PLACE WHERE YOU OBTAINED IT
AND YOUR MONEY WILL BE REFUNDED. ADVANCED TELECOMMUNICATIONS MODULES LIMITED
(ATML) SOFTWARE IS LICENSED NOT SOLD.

FOR THE LIMITED WARRANTY PERTAINING TO THIS PRODUCT, PLEASE REFER TO THE
WARRANTY LEAFLET INCLUDED WITH THIS PACKAGE.

1. LICENSE. The application, demonstration, system and other software
accompanying this License, whether on disk, in read-only memory, or on any other
media (the "ATML Software"), and the related documentation are licensed to you
by Advanced Telecommunications Modules Limited (ATML). You own the medium on
which the ATML Software are recorded, but ATML and/or ATML's licensor(s) retain
title to the ATML Software and related documentation. The License allows you to
use the ATML Software on a single ATML product and only make one copy of the
ATML Software in machine-readable form only for backup purposes. You must
reproduce, on such copy, the ATML copyright notice and any other proprietary
legends that were on the original copy of the ATML Software. You may also
transfer all your license rights in the ATML Software, the backup copy of the
ATML Software, the related documentation, and a copy of this License to another
party, provided the other party reads and agrees to accept the terms and
conditions of this License.

2. RESTRICTIONS. The ATML Software contains copyrighted material, trade secrets,
and other proprietary material. In order to protect them, and except as
permitted by applicable legislation, you may not decompile, reverse engineer,
disassemble, or otherwise reduce the ATML Software to a human-perceivable form:
copy, modify, network, rent, lease, loan, or distribute the ATML Software: or
create derivative works based upon the ATML Software in whole or part. You may
not electronically transmit the ATML Software from one computer to another or
over a network.

3. TERMINATIONS. This License is effective until terminated. You may terminate
the License at any time by destroying the ATML Software, related documentation
and all copies thereof. This License will terminate immediately without notice
from ATML if you fail to comply with any provision of this License. Upon
termination you must destroy the ATML Software, exclusions in this License
Agreement and shall have no right to any refund of any amount paid for the ATML
Software. No termination shall release you from liability for any breach of this
License Agreement.

4. EXPORT LAW ASSURANCE. You agree and certify that neither the ATML Software
nor any other technical data received from ATML, nor the direct product thereof,
will be shipped, transferred, or exported, directly or indirectly, to any
country in violation of any applicable law, including the United States Export
Administration Act and the regulations thereunder.

5. CONTROLLING LAW AND SEVERABILITY. This License shall be governed by and
construed in accordance with the laws of England. If for any reason a court of
competent jurisdictions finds any provision of this License, or portion thereof,
to be unenforceable, that provision of the License shall be enforced to the
maximum extent permissible so as to effect the intent of the parties, and the
remainder of this License shall continue in full force and effect.

6. ACKNOWLEDGMENT. You acknowledge that you have read this License Agreement,
understand it, and agree to be bound by its terms and conditions. You also agree
that the License agreement is the complete and exclusive statement of agreement
between the parties and supersedes all proposals or prior agreements, oral or
written, and any






other communications between the parties relating to the subject matter of the
License Agreement. No amendment to or modification of this License will be
binding unless in writing and signed by a duly authorized representative of
ATML.



                                       2.





                                    EXHIBIT G
                                    TERRITORY


The World








                                    EXHIBIT H
                                  F.O.B. POINT


                              GSS/Array Technology
                                6835 Via Del Oro
                                   San Jose CA
                                   95119-1315

                               408-229-6100 Phone
                                408-362-3111 Fax








                                    EXHIBIT I
                 MANUFACTURER'S STANDARD PRODUCT WARRANTY PERIOD

        ATM Network Adapters                  [*]

        ATM Switches                          [*]

        Spare parts and spare kits            [*]




*Certain information on this page has been omitted and filed separately with the
 Commission. Confidential treatment has been requested with respect to the
 omitted portions.








                                    EXHIBIT J
                         ADVANCE NOTIFICATION AGREEMENT

Manufacturer agrees to notify Purchaser in writing, ninety (90) days in advance
of shipments to Purchaser, any form, fit, or functional changes to products
procured by Purchaser. In the event a critical situation occurs which forces a
change to occur within the ninety (90) day notification period, Purchaser will
also be provided with immediate notification.

Furthermore, Manufacturer agrees to provide Purchaser with the option to
evaluate potential changes which affect form, fit, or function, in advance of
forecasted or requested shipments to Purchaser. If the changes are deemed
unacceptable to Purchaser, upon written notification, Manufacturer will supply
Purchaser with up to six months of the forecasted requirements at the previous
configuration before making the proposed change. If the Manufacturer is not able
to provide the previous configuration, manufacturer will

i.      accommodate the requirements of the Purchaser in the changed
        configuration, or

ii.     collaborate with, and assist the Purchaser in making changes to
        Purchaser's product to accommodate changes, or

iii.    provide end of life products per agreement.

If Purchaser does not provide a written request to evaluate the potential
changes within ten (10) working days of notification by Manufacturer,
Manufacturer is not obligated to supply Purchaser with the previous
configuration.


                                       1.






                     ADVANCED TELECOMMUNICATIONS MODULES INC.
               (HEREIN ATMI) STANDARD TERMS AND CONDITIONS OF SALE


1       TERMS OF SALE THE TERMS OF SALE CONTAINED HEREIN APPLY TO ALL QUOTATIONS
        MADE AND PURCHASE ORDERS ENTERED INTO BY THE SELLER, WHETHER IN
        DOCUMENTARY FORM OR TRANSMITTED BY ELECTRONIC MEANS. SOME OF THE TERMS
        SET OUT HERE MAY DIFFER FROM THOSE IN BUYERS PURCHASE ORDER AND SOME MAY
        BE NEW. SELLERS ACCEPTANCE IS CONDITIONAL ON BUYERS ASSENT TO THE TERMS
        SET OUT HERE IN LIEU OF THOSE IN BUYER'S PURCHASE ORDER. SELLER'S
        FAILURE TO OBJECT TO PROVISIONS CONTAINED IN ANY COMMUNICATION FROM
        BUYER SHALL NOT BE DEEMED A WAIVER OF THE PROVISIONS OF THIS ACCEPTANCE.
        ANY CHANGES IN THE TERMS CONTAINED HEREIN MUST SPECIFICALLY BE AGREED TO
        IN WRITING BY AN OFFICER OR MANAGER OF THE SELLER BEFORE BECOMING
        BINDING ON EITHER THE SELLER OR THE BUYER. All orders or contracts must
        be approved and accepted by the seller at its home office. These terms
        shall be applicable whether or not they are attached to or enclosed with
        the product to be sold hereunder. No shipments will be made until a
        signed Purchase Order or other appropriate document is received by
        Seller. These terms do not apply to the licensing of software products
        offered by the Seller. Such products are made available only under the
        terms of Seller's standard software license terms.

2       TAXES Unless otherwise specifically provided herein, the amount of any
        present or future sales, revenue, excise or other tax to the product
        covered by this order or the manufacture or sale thereof, shall be added
        to the purchase price and shall be paid by the Buyer, or in lieu thereof
        the Buyer shall provide the Seller with a tax exemption certificate
        acceptance to the taxing authorities. In the event Seller is required to
        pay any such tax, fee or charge at the time of Sale or thereafter, the
        Buyer shall reimburse Seller therefor.

3       ORDERS Buyers shall supply Seller with a letter or purchase order on
        company letter head. Buyer's orders should state desired shipping date,
        but Seller is under no obligation to meet Buyer's expected delivery date
        Orders placed by Buyer and acknowledged by Seller will be subject to the
        terms listed below in the payment section. No purchase order shall be
        binding until accepted by Seller in writing

4       SHIPMENT Unless otherwise specified on the face hereof, shipments of
        goods within and outside the U.S. shall be delivered FOB Seller's dock,
        and title and liability for loss or damage thereto shall pass to Buyer
        upon Seller's tender of delivery of the goods to carrier for shipment to
        Buyer, and any loss or damage thereafter shall not retrieve Buyer of any
        obligation hereunder. Buyer shall reimburse Seller for taxes and any
        other expenses incurred for licenses for clearance required at port of
        entry and destination. Seller may deliver the good in installments.
        Unless otherwise agreed, all items shall be packed in accordance with
        Seller's normal practices. Buyer shall pay the per unit carriage and
        insurance amount attributable to each product, as specified in Seller's
        Price List in effect at the time of this Acknowledgment.

5       PAYMENT
        (a)    Unless otherwise agreed all invoices are due and payable thirty
               (30) days from date of invoice. No discounts are authorized.
               Shipments, deliveries and performance of work shall at all times
               be subject to the approval of the Seller's credit department and
               the Seller may at any time decline to make any shipments or
               deliveries or perform any work except upon receipt of payment or
               upon terms and conditions or security satisfactory to such
               department.

        (b)    If, in the judgment of the Seller, the financial condition of the
               Buyer at any time does not justify continuation of production or
               shipment on the terms of payment originally specified, the Seller
               may require full or partial payment, in advance, and, in the
               event of the bankruptcy or insolvency of the Buyer or in the
               event any proceeding is brought by or against the Buyer under the
               bankruptcy or insolvency laws, the Seller shall be entitled to
               cancel any order then outstanding and shall receive reimbursement
               for its cancellation charges.


                                       2.







        (c)    Each shipment shall be considered a separate and independent
               transaction, and payment therefor shall be made accordingly. If
               shipments are delayed by the Buyer, payment shall become due on
               the date when the Seller is prepared to make shipment. If the
               work covered by the purchase order is delayed by the Buyer,
               payments shall be made based on the purchase price and the
               percentage of completion. Products held for the Buyer shall be at
               the risk and expense of the Buyer.

        (d)    Customer grants and ATMI retains a purchase money security
               interest in each Product furnished hereunder and any proceeds
               thereof, until the full purchase thereof shall have been paid in
               full.

6 SHIPPING DATES All shipping dates are estimates only and are dependent upon
prompt receipt of the necessary information from Buyer. Shipments may be made in
installments. Seller shall be excused from performance and shall not be liable
for any delivery or for non delivery, in whole or in part, caused by the
occurrence of any contingency beyond the reasonable control of Seller, including
but not limited to war (whether an actual declaration thereof is made), sabotage
or other act or civil disobedience, judicial action, labor dispute, accident,
defaults of suppliers, fire, act of God, shortage of labor, fuel, raw materials
or machinery or technical or yield failure where Seller has exercised ordinary
care in the prevention thereof. Seller may at its sole discretion allocate
production and delivery among Seller's customers.

7       RESCHEDULING/CANCELLATION

        (a)    No delivery delay requested by Buyer on an order placed will be
               effective unless covered by an amendment to the order that
               provides for the payment of any agreed upon costs the delay
               imposes on Seller and that it is signed by a duly authorized
               representative of Seller.

        (b)    Products returned for convenience of Buyer if accepted by Seller
               shall be subject to a restocking fee.

        (c)    Buyer may not cancel or reschedule any order scheduled for
               delivery within thirty (30) days

        (d)    A cancellation charge shall be assessed to Buyer on order for
               standard ATMI products which are canceled within sixty (60) days
               of the scheduled delivery date. The amount of such charge shall
               be based on the quantity canceled and the time remaining.



                                       3.







ADVANCED                                 Advanced Telecommunications Modules Inc
TELECOMMUNICATIONS                                         1130 E. Arques Avenue
MODULES                                                      Sunnyvale, CA 94086
                                                                 Ph 408 523 1400
                                                                 Fx 408 523 1410

June 12, 1996

Com21, Inc
1991 Landings Drive
Mountain View, CA 94043

Dear Sir:

INTERNATIONAL OEM AGREEMENT


We refer to the above agreement entered into between us on 7th March 1996
("Agreement").

We have discussed certain provisions of the Agreement and agreed that certain
changes and additions, as set out in this letter will be made to the Agreement.
This letter sets out the terms of our agreement as follows:

1.      Defined terms in the Agreement shall have the same meaning in this
        letter.

2.      Clause 6.1 of the Agreement shall be amended by:

2.1     the deletion of the words "an exclusive" in the first line of that
        clause and the insertion, in the same place, of the words "a non
        exclusive"; and

2.2     the deletion of the words "Exhibit H" in the fourth line of that clause
        and the insertion in the same place, of the words "Exhibit G"

        such that Clause 6.1 shall, from the date of the letter be deemed to
        read:

        6.1     License to purchaser. Manufacturer hereby grants to Purchaser a
                non exclusive (except for the usage rights reserved to
                Manufacturer),royalty-free, fully paid license to use,
                distribute, demonstrate and sub-license the object code of the
                Software in the Territory specified in Exhibit G attached hereto
                in carrying out the Purchaser's obligations under the provisions
                of this Agreement. The license shall terminate on the
                termination of this Agreement for any reason.

3.      COM21 hereby unconditionally and irrevocably waives any claim that it
        has or which it may have as a result of any breach of Clause 6.1 which
        may have occurred prior to the date of this letter.

4.      ATM Inc. will not, for a period of two years from the date of this
        letter manufacture for sale cable modem head-end devices.

5.      ATM Inc. will not from the date of your acceptance of the terms of the
        letter, convey to any other party COM21 technology information or COM21
        product features that ATM Inc. learns during the course of doing
        business with COM21 unless such information is or falls into the public
        domain (other than in breach of the terms of this letter or any other
        confidentiality agreement between us).


*Certain information on this page has been omitted and filed separately with the
 Commission. Confidential treatment has been requested with respect to the
 omitted portions.

                                       4.







6.      The remaining terms in the Agreement, including for the avoidance of
        doubt Clause 10, shall remain in full force and effect and shall remain
        binding obligations of ATM Inc. and COM21 in accordance with their
        terms.

7.      This letter shall be covered by and construed under the laws of the
        State of California, USA. The federal and state courts within the State
        of California shall have exclusive jurisdiction to adjudicate any
        dispute arising out of this letter. COM21 expressly consents to (1) the
        personal jurisdiction of the federal and state courts within California,
        (ii) service of process being effected upon it by registered mail sent
        to the address set forth at the beginning of this letter, and (iii) the
        uncontested enforcement of a final judgement from such court in any
        other jurisdiction wherein COM21 or any of its assets are present.

We should be grateful if you could indicate your acceptance of the above terms
by signing and returning the enclosed copy letter to us.

Yours faithfully



---------------------------------------
for and on behalf
ATM Inc.


We hereby and agree to and accept the terms of this letter.

-----------------------------------
For and on behalf of COM21, Inc.


----------------------
Date



                                       5.