Purchase and License Agreement - Siemens AG and Com21 Inc.


                                   SIEMENS AG
                         PURCHASE AND LICENSE AGREEMENT


            This Purchase and License Agreement (the "Agreement") is entered
into as of the Effective Date by and between COM21, Inc. ("COM21"), with offices
at 750 Tasman Drive, Milpitas, California 95035, USA and Siemens AG, Public
Communication Networks Group ("Siemens"), Munich, with offices at Hofmannstrasse
51 D-81359 Munchen, Germany.

            1.    INTRODUCTION

            1.1 COM21 has developed certain cable TV data interfaces with
associated firmware and software, all of which are collectively referred to in
this Agreement as "Products" and more particularly described in Exhibit A
hereto.

            1.2 Siemens wishes to purchase (or license, as applicable) the
Products from COM21 and sell, lease or otherwise dispose of the Products through
itself and its Subsidiary Companies throughout the world.

            1.3 COM21 shall supply Siemens with Products and associated
documentation and shall provide the services subject to the terms and conditions
of this Agreement.

            2.    LIST OF EXHIBITS

            The following Exhibits are attached to and incorporated into and
made a part of this Agreement

            a)    Description/Specification of Products..............Exhibit A

            b)    Prices and Discounts...............................Exhibit B

            c)    COM21 Support Terms and Conditions.................Exhibit C

            d)    COM21 Warranty and Service Policy..................Exhibit D

            3.    DEFINITIONS

            "Cable Modem Product" means, collectively, the COM21 subscriber-end
data over cable modem and enhancements, upgrades and new versions thereof
manufactured by or on behalf of COM21 (but not manufactured by Siemens).

            "COM21 Headend Product" means, collectively, the COM21 headend
controller unit and enhancements, upgrades and new versions thereof manufactured
by or on behalf of COM21 (but not manufactured by Siemens).



     2

            "Confidential Information" means information relating to the
business or anticipated business of either party including, but not limited to,
trade secrets, know-how, inventions (whether patentable or not), ideas,
improvements, works of authorship, derivative works, modifications, product
development plans, forecasts, strategies, names and expertise of employees and
consultants, techniques, processes, algorithms, software programs, schematics,
designs, contracts, customer lists, financial information, sales and marketing
plans and all other business and technical information. In particular, but
without limitation, the Software source code shall be the Confidential
Information of COM21.

            "Effective Date" means the last date on which a party has executed
this Agreement.

            "End-User" means a cable owner or operator, Multiple Systems
Operator, program provider or any holding company or Subsidiary Company thereof
or any other person or entity that provides or has plans to provide data or
cable services.

            "Epidemic Failure" means an identical fault of 10% of the Products
delivered to Siemens hereunder during a thirty-six (36) month period which
failed to comply with the warranty set forth in Section 14.1.

            "Products" means collectively the Cable Modem Product, COM21 Headend
Product and the Software, as more particularly described in Exhibit A.

            "Software" means, collectively, the COM21 network management
applications programs and other software for the COM21 Headend Product and COM21
modem image software and other software for the Cable Modem Product, in object
code form, as described in Exhibit A, and enhancements, upgrades and new
versions thereof.

            "Subsidiary Company" means any entity which is owned or controlled
directly or indirectly by a party hereto as to fifty percent (50%) or more of
the issued shares and/or voting rights entitled to vote for the election of
directors or other governing authority or otherwise having power to control such
entity's general activities, but only for so long as such ownership or control
shall continue.

            "Territory" means every country in the world, excluding the Republic
of South Korea and the Democratic Peoples' Republic of Korea (North Korea).

            "Update" means a change or addition to the Software ( including,
without limitation, modifications and revisions) that correct errors, problems
or defects or that provide corrections. An Update is denoted by the third digit
of release number. For example, version 2.1.1 would be an Update of version 2.l.

            4.    PRODUCTS



                                       2.
     3

            4.1 Subject to all the terms and conditions of this Agreement, COM21
hereby appoints Siemens for the term of this Agreement as a non-exclusive
distributor of the Products only within the Territory. Products may be
distributed by Siemens and, if so appointed by Siemens, by its Subsidiary
Companies and other third parties which may act as subdistributors of Siemens.
The appointment of third parties other than Subsidiary Companies of Siemens as
subdistributors shall require COM21's prior written consent. Notwithstanding the
foregoing any such Subsidiary Company and third party subdistributor shall be
bound in writing to all the restrictions on Siemens contained in this Agreement
and Siemens shall ensure in its written contracts with such Subsidiary Companies
and third party subdistributors compliance by the Subsidiary Company or third
party subdistributor, as the case may be, with such restrictions. In addition,
Siemens shall provide in its written contracts with all third party
subdistributors of the Products that COM21 is a third party beneficiary of such
contract for the purpose of enforcing such restrictions.

                  (i) Siemens shall indemnify and hold COM21 harmless from and
against all liabilities, damages, losses, costs and expenses caused by the
failure of any Subsidiary Company or third party subdistributor appointed by
Siemens to comply with restrictions on Siemens contained in this Agreement.
Siemens' obligation of indemnity pursuant to this subparagraph 4.1(i) arising
from a third party, subdistributor's failure to comply with such restrictions
shall subject to the liability limitations set forth in Section 27 below,
provided Siemens (i) promptly notifies COM21 of any such noncompliance of which
Siemens becomes aware and (ii) uses its best efforts to mitigate the effect of
such non-compliance exercising such rights as Siemens may have available at law
or in equity including, without limitation, termination of the third party
subdistributor's appointment and ceasing supply of Products to such
subdistributor. In the event that Siemens fails to take legal action against a
third party subdistributor within thirty (30) days after first becoming aware of
such subdistributor's non-compliance with applicable restrictions, COM21 shall
may elect, but shall have no obligation, to undertake its own action or
proceeding against such third party subdistributor and Siemens shall provide
COM21 with reasonable assistance and cooperation in connection with such action
or proceeding.

            4.2 Subject to all the terms and conditions of this Agreement, COM21
hereby grants to Siemens the following non-exclusive, sublicensable (to Siemens'
Subsidiary Companies and appointed third party subdistributors only) and
non-transferable licenses within the Territory:

                  (i) a license to use the Software solely for Siemens' and
Siemens' Subsidiary Companies' internal purposes in connection with the
installation, commissioning, testing and operation of the Products;

                  (ii) a license to distribute and sublicense the Software to
End-Users only for use with the Products; and


                                       3.
     4

                  (iii) a license to copy, or have copied, Software Updates
provided to Siemens by COM21 for incorporation into the hardware of the Products
marketed in accordance with Section 4.1 above.

            4.3 Siemens may distribute the Products only to persons and entities
located and taking delivery within the Territory. Siemens acknowledges and
understands that COM21 has granted Dacom International and Dacom, Inc. exclusive
rights to distribute the Products in the Republic of South Korea and, when
distribution becomes legally permissible, in the Democratic Peoples' Republic of
Korea (North Korea) (the "Excluded Territory"). Therefore, no distribution of
the Products shall be made by Siemens, any Subsidiary Company or other sales
outlet to any person or entity where Siemens, such Subsidiary Company or other
sales outlet knows or has reason to believe that the ultimate end user of such
Product is located within the Excluded Territory. COM21 will notify Siemens if
COM21 becomes aware of any distribution of the Products into the Excluded
Territory, directly or indirectly, by Siemens or any Subsidiary Company or other
sales outlet. Upon receipt of such notification from COM21, Siemens will use its
best efforts to retrieve, within thirty (30) days, all shipments of the
Products, and terminate all future distribution of the Products, in the Excluded
Territory. COM21 shall be entitled to terminate this agreement immediately if
Siemens fails to successfully retrieve all such Products.

                  (i) Siemens shall indemnify and hold COM21 harmless from all
liabilities, damages, losses, costs and expenses caused by distribution of the
Products in the Excluded Territory by a Subsidiary Company or other sales
outlet. Siemens' obligation of indemnity pursuant to this subparagraph 4.3(i)
arising from distribution of the Products in the Excluded Territory by a third
party subdistributor or other sales outlet shall be subject to the liability
limitations set forth in Section 27 below, provided Siemens uses its best
efforts to terminate such distribution of the Products by exercising such rights
as Siemens may have available at law or in equity including, without limitation,
termination of the third party subdistributor's appointment and ceasing supply
of Products to such subdistributor.

            4.4 In addition to the rights granted under Section 4.2 above,
Siemens, its Subsidiary Companies and appointed third party subdistributors
shall have the right to entitle End-Users of the Products to transfer the rights
under Software sublicenses, subject to Sections 4.6 and 4.8, with a transfer of
the Products, provided Siemens and such Subsidiary Companies use commercially
best efforts to ensure that such End-User does not retain any copies of the
Software that were not separately sublicensed by Siemens, its Subsidiary
Companies or appointed third party subdistributors.

            4.5 The Software contains valuable confidential and proprietary
information and trade secrets of COM21 and its licensees which have not been
published or otherwise placed in the public domain. Siemens shall not authorize
nor permit any of its Subsidiary Companies, other sales outlets, licensees or
any other third party to disassemble or reverse engineer or decompile the
Software or otherwise attempt to learn the source code or the internal
structure, sequence or 



                                       4.
     5

organization of the Software, algorithms or underlying ideas contained in the
Software, except as specifically authorized by applicable compulsory law.

            4.6 As between the parties, COM21 retains and shall exclusively own
all title to, and except as expressly and unambiguously licensed herein, all
rights (including all patent rights, copyright rights, mask work rights, trade
secret rights, contract rights and all other intellectual property and
proprietary rights anywhere in the world) and interest in the Software, any
other software or firmware contained in the Products and all modifications,
improvements and derivative works (by whomever produced) thereof and
Documentation (as defined in Section 11); provided, however, COM21 shall have no
rights hereunder to any software or computer code developed by or for Siemens
using the application programming interfaces contained in the Software.

            4.7 Siemens shall not, without prior written consent of COM21,
delete, alter, obscure, modify or fail to reproduce in and on any copy of the
Software, the name of such Software and any copyright or other proprietary
notices appearing in or on such Software provided by COM21. The same shall
apply, subject to Section 11, third paragraph, and Section 17.2 with respect to
Documentation and training materials provided by COM21.

            4.8 All sublicenses granted by Siemens shall provide adequate
protection for COM21's intellectual property rights in the Software. Siemens
shall distribute and sublicense, or permit a transfer of the rights regarding
Software under a sublicense, the Software licensed to Siemens hereunder to
End-Users under terms and conditions no less protective with regard to such
Software as Siemens licenses its own software to End-Users. All copies of the
Software are licensed according to Sections 4.2 and 4.4 and not sold.

            5.    TERM OF AGREEMENT

            The initial term of this Agreement shall commence on the Effective
Date and continue in effect for a period of (5) five years. This Agreement may
be renewed for successive one (1) year renewal terms upon prior written
agreement of the parties.

            6.    FORECASTS

            On the Effective Date, and at least every two (2) months thereafter,
Siemens shall provide COM21 with a twelve (12)-month forecast in writing of
orders for Products to be placed with COM21 for delivery during each of the
twelve (12) succeeding months (or such lesser number of months remaining during
the term of this Agreement). If any change in the forecast is known by Siemens,
Siemens will promptly update the forecast to reflect such change and provide the
updated forecasts to COM21. Each such forecast shall represent Siemens' best
estimate of its monthly requirements for Products during the period of the
forecast but shall be advisory only and shall not be binding on Siemens.



                                       5.
     6

            7.    ORDERING PROCEDURE

            7.1 Siemens shall order Products by issuing written orders
("Orders") to COM21 at the address for COM21 stated in Section 30 below.

            7.2 Orders shall be governed by the terms of this Agreement.
Different or additional terms contained in any Order shall be subject to written
acceptance by COM21.

            7.3 COM21 shall accept or reject Orders received from Siemens within
three (3) business days of receipt of such Order. COM21 shall have no liability
to Siemens with respect to any Order which is not accepted by COM21.

            COM21 may reject an Order only to the extent it exceeds the
forecasts as per Article 6 by more than thirty (30%), is otherwise not in
conformance with the terms and conditions this Agreement or otherwise imposes
unreasonable or likely unattainable commercial terms on COM21.

            Acceptance or rejection of an Order must be sent by fax followed by
letter to the Siemens department which issues the Order.

            7.4 Siemens shall not submit any Order in an amount less than TWO
THOUSAND DOLLARS (US$2,000); provided, however, Siemens shall use its best
commercially reasonable efforts to ensure that each Order submitted to COM21 is
in an amount of not less than TWENTY THOUSAND DOLLARS (US$20,000).

            8.    PRICES

            8.1 [*]

            Prices are EXW (ExWorks, Incoterms 1990). COM21's shipping dock and
include COM21's standard commercial packaging.

            The prices for spare parts shall reflect COM21's manufacturing
and/or acquisition costs of the respective parts plus reasonable margins.

[*] 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. 
                                       6.
     7

            8.2 COM21 shall have the right, in its sole discretion from time to
time, to change such prices within thirty (30) days' prior written notice. In
the event of a price decrease, new prices will apply to all shipments made after
such notice period. In the event of a price increase, new prices will apply to
all Orders accepted by COM21 after the notice period. New increased prices will
not apply to Orders placed before the date of the notice and to Orders resulting
from quotations made by Siemens or a Subsidiary Company within the one hundred
and eighty (180) day period preceding the date of the notice.


            9.    DELIVERY

            9.1 Delivery times ("Delivery Time") for the Products shall be:

            Complete units of Products:   8 weeks
            Spare parts:                  6 weeks

                  after acceptance by COM21 of an Order.

            Delivery Times for repaired or replaced parts of Products shall be
fifteen (15) days after receipt by COM21 of faulty parts returned by Siemens.

            9.2 Siemens shall be entitled to place emergency orders for minor
quantities one (1) Headend Product and ten (10) units of Cable Modem Product per
emergency order by giving notice by fax (with written confirmation sent by
mail). For purposes of this Section 9.2, an Emergency Order is an Order placed
by Siemens in response to an urgent End User request arising out of
extraordinary circumstances. COM21 will use commercially reasonable efforts to
ship Products pursuant to an Emergency Order, not to exceed two (2) Emergency
Orders per month or twelve (12) Emergency Orders in any consecutive twelve (12)
month period, within two (2) days of COM21's acceptance of the Emergency Order.

            9.3 Should circumstances arise that may result in a delayed delivery
by COM21, COM21 shall promptly notify Siemens of such circumstances.

            In the event of COM21's delay in delivery of Products beyond the
times, set forth above in 9.1, except by reason of Force Majeure, Siemens shall
be entitled to a payment in the amount of [*] of the purchase price of the
delayed Products for each business day the Products are delayed not to exceed
[*] of the total purchase price of such Products.

            In the event the delay exceeds two (2) months, Siemens shall, in
addition to the aforestated rights, be entitled to cancel the order wholly or in
part without incurring any liability. COM21 shall indemnify and hold harmless
Siemens against direct damages resulting from such cancellation, provided
Siemens has exercised its best efforts to minimize such direct damages and

[*] 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. 

                                       7.
     8

excluding consequential and incidental damages and damages resulting from
procurement of substitute goods or Siemens' negligence or wilful misconduct.

            9.4 Delivery shall be ExWorks (EXW, Incoterms 1990), COM21's
shipping dock. Title to the Products (other than Software) and risk of loss
shall pass to Siemens upon delivery to the carrier at such shipping dock.
Shipping charges shall be paid by Siemens. Insurance coverage on all shipments
is the sole responsibility of Siemens.


            10.   DEMONSTRATION COM21 PRODUCTS

            In order to accommodate the deployment of cable modems COM21 provide
equipment to Siemens for demonstration, testing and service purposes as follows:

            Munchen World-Wide Support:

            Upon Siemens' request, COM21 will provide demonstration equipment
for Siemens Munchen world-wide support as follows:

  
  
ITEMS                                 COST (TRANSFER PRICE) TO SIEMENS
-----                                 --------------------------------
                                                                             
10 ComPORTS                           COM21's fully burden manufacturing cost only
2 ComCONTROLLER                       COM21's fully burden manufacturing cost only
2 NMAPS                               No charge for license
  

            The above prices include upgrade fees to keep the software and
hardware at the current and newest technical level.

            Subsidiary Companies:

            Upon Siemens' request, COM21 will provide demonstration equipment
for Subsidiary Companies of Siemens as follows:

  
  
ITEMS                                  COST (TRANSFER PRICE) TO SIEMENS
-----                                  --------------------------------
                                                                     
10 ComPORTS                            COM21's current price list for demo
                                       equipment and current price list for extended
                                       hardware warrant contracts

ComCONTROLLER                          COM21's current price list for demo
                                       equipment and current price list for extended
                                       hardware warrant contracts
  

                                       8.
     9

  
                                                                     
NMAPS                                  No charge for license and upgrade fees
  

            If one year after purchasing the demonstration system, the
Subsidiary Company wins contracts for accumulated more than 2,000 cable modems,
COM21 will agree to provide the Subsidiary Company a credit equal to fifty
percent of the amount of the demonstration system purchased for the site
including software and hardware upgrade maintenance fees paid. Such refund will
be done only once per Subsidiary Company. In order to assist Siemens, Munchen
World-Wide Support and Siemens Subsidiary Companies in maintaining adequate
product support, sales and marketing capabilities for future versions of the
Products and new COM21 products, COM21 agrees that all terms and conditions set
forth above shall apply also to new Product versions and Product lines that
COM21 makes commercially available.

            11.   DOCUMENTATION AND ACCESSORY

            COM21 shall, upon execution of this Agreement, provide Siemens, free
of charge, one (1) set of the documentation associated with each of the Products
(the "Documentation"). Additional copies of the Documentation will be available
for purchase by Siemens.

            All Documentation for a Product shall comply with COM21's most
recent technical standards for such Product and shall be updated to include
Product modifications. COM21 shall provide Siemens without delay and free of
charge one (1) copy of all updates of the Documentation for each Product
supplied by COM21 hereunder when COM21 makes such updates generally available to
its other resellers. The foregoing obligation shall apply not only during the
term of this Agreement but also after its expiry for such time as such Products
are used by End-Users or its Subsidiary Companies. In addition, COM21 shall use
commercially reasonable efforts during the term of this Agreement to promptly
provide Siemens, before the next generally available update without delay and
free of charge, information about changes in the Documentation for Products
supplied by COM21 hereunder.

            Siemens shall be entitled to copy, modify (as long as the meaning of
the content is not changed), translate and use COM21's Documentation, subject to
the terms and conditions of this Agreement. Siemens may attach to such
Documentation its own copyright notices and supply any copied, modified or
translated Documentation to End-Users, Subsidiary Companies and other resellers.
Siemens shall make commercially reasonable efforts to promptly provide COM21,
free of charge, one (1) copy of any and all such modifications and translations
of the Documentation made by or on behalf of Siemens. Where Siemens is entitled
to allow sublicensing, it may sublicense the rights set forth in this paragraph
to its resellers and sublicensees.

            12.   TERMS OF PAYMENT

            12.1 Payment shall be effected in US dollars and shall be due thirty
(30) days after receipt of COM21's invoice.



                                       9.
     10

            Payment shall not constitute acceptance of the Products by Siemens.

            12.2 In the event that Siemens does not render undisputed payments
at the due dates thereof, COM21 shall be entitled to interest on such delayed
payments at an interest rate of one percent (1%) per month or, if lower, the
maximum rate permitted under applicable law.

            12.3 Siemens will pay all charges pursuant to ExWorks (EXW,
Incoterms 1990) including, without limitation, transportation charges and
insurance premiums, taxes not relating to Com21's income (subject to Section 13)
and all government permit fees, license fees, customs fees and similar fees,
duties and other governmental assessments in connection with this Agreement and
the performance of COM21's or Siemens' obligations hereunder.

            12.4 COM21 shall not invoice any value-added-tax to Siemens.

            13.  TAXES

            13.1 Except as otherwise provided in Sections 12.3 and 12.4 above
the principle shall apply that any party shall bear and pay the taxes, charges
and other duties imposed on it.
In particular the following shall apply:

                  (i) Any and all taxes, charges and/or other duties
(hereinafter "Taxes") imposed by the laws of the Federal Republic of Germany on
COM21 with respect to any payments to be made by Siemens to COM21 under or in
connection with this Agreement shall be borne and paid by COM21. If required by
the laws of the Federal Republic of Germany, Siemens shall deduct Taxes imposed
in Germany on payments to be made by Siemens under or in connection with this
Agreement. Taxes imposed by the Federal Republic of Germany on such payments and
shall pay over to the proper German tax authorities any and all amounts withheld
by Siemens from payments to COM21.

                  (ii) To the extent the Double Taxation Convention between the
Federal Republic of Germany and the United States of America allows COM21 to
credit Taxes imposed on and paid by COM21 according to the laws of the Federal
Republic of Germany against Taxes imposed on and to be paid by COM21 according
to the laws of the United States of America, Siemens shall provide to COM21
official tax receipts issued by the German tax authorities or other
documentation evidencing the payment by Siemens on behalf of COM21 of Taxes
imposed by the Federal Republic of Germany on payments made by Siemens to COM21
under or in connection with this Agreement, the sum total of Taxes reflected on
such official tax receipts or other documentation to equal the sum of all
amounts withheld by Siemens pursuant to this Section 13.

                  (iii) To the extent the Double Taxation Convention between the
Federal Republic of Germany and the United States of America entitles COM21 to
claim a reduction of or an exemption from Taxes imposed on and to be paid by
COM21 according to the laws of the Federal 



                                      10.
     11

Republic of Germany, Siemens shall use all reasonable efforts to support COM21
in obtaining a tax reduction/exemption certificate (or the like) from the German
tax authorities if so requested by COM21, to validate such a claim by COM21 for
tax reduction of or exemption from Taxes imposed on or to be paid by COM21
according to the laws of the Federal Republic of Germany. As long as Siemens has
not received a copy of such tax reduction/exemption certificate, Siemens shall
be entitled to deduct the full amount of Taxes from the payments to be made to
COM21 and to pay over to the proper German tax authorities the amount required
by the laws of the Federal Republic of Germany to be withheld absent any
entitlement to a reduction of or exemption from Taxes imposed by the Federal
Republic of Germany.


            14.   WARRANTY

            14.1 COM21 warrants only to Siemens that:

                  (i) on the date of delivery, COM21 holds title to the Products
free and clear of any security interest, lien or encumbrances and that the
hardware portions of the Cable Modem Product and COM21 Headend Product are newly
manufactured, contain new parts, comply with the requirements stated in Article
14 below;

                  (ii) for a period of fifteen (15) months from the date of
shipment to Siemens of each Modem Product and copy of the Software, and for a
period of eighteen (18) months from the date shipment to Siemens, each COM21
Headend Product (the "Warranty Period"), conforms with COM21's published
specifications for such Product (attached hereto in Exhibit A), and each Product
is free from material defects in design, material and workmanship;

                  (iii) the media provided by COM21 containing the Software is
free from physical defects; and

                  (iv) that the Software substantially conforms with COM21's
published specifications for the Software, as set forth in Exhibit A and, to the
best of COM21's knowledge as of the Effective Date, the Software delivered by
COM21 is free from viruses.

            14.2 Siemens may purchase an extended warranty for the Cable Modem
Product and the COM21 Headend Product and extended maintenance for the Software
as stated in Exhibit D.

            14.3 Siemens shall handle and be responsible for all warranty
returns of the Products from its direct and indirect customers. Siemens shall
notify COM21 within the Warranty Period of Products obtained from COM21 which do
not comply with the above warranty and shall obtain a Return Materials
Authorization ("RMA") number from COM21. At the time COM21 issues the RMA number
to Siemens, COM21 will notify Siemens of the freight forwarder to be used for
shipment back to Siemens of returned and repaired Products. Products returned
(by Siemens only) 



                                      11.
     12

to COM21 during the Warranty Period (as shown by appropriate documentation) will
be repaired or replaced, at COM21's option, and delivered as stated in Exhibit D
at no cost to Siemens. Alternatively, Siemens may, at the expense of COM21,
replace the Products having failed to conform to the warranty with Products in
stock and COM21 shall replenish such stock following COM21's receipt of the
defective Products. COM21 will bear the cost of freight and insurance of
returned and repaired Products, such freight forwarder to be selected by COM21.
All returned Products must be secured by sufficient packaging, which shall
conspicuously bear the RMA number Siemens obtains from COM21 prior to return.
The Warranty Period for a Product following repair or replacement of such
Product shall continue for the longer of ninety (90) days or remainder of the
Warranty Period beginning after return shipment of the replaced or repaired
Product.

            In the event the failure rate of any delivery lot exceeds ten
percent (10%) of the lot and subject to verification by COM21, COM21 shall
replace the entire lot free of charge on an Emergency Order Basis.

            If any Software including firmware supplied by COM21 hereunder fails
to conform to the warranty in clause (iv) above and such failure is
reproducible, COM21 shall correct the Software at no cost to Siemens in
accordance with the error correction procedure set out in Exhibit E hereto.

            14.4 After expiration of the Warranty Period, COM21 will repair
Products within fifteen (15) business days after COM21's receipt of the
defective Product, on a time and materials basis at prices and charges as set
forth in Exhibit C and such prices and charges shall not be higher than those
provided by COM21 to third parties. COM21 will warrant such out-of-warranty
repair of COM21 Products for a period of ninety (90) days from the date of
repair, pursuant to the terms of Section 14.5.

            14.5 The warranty set forth in Section 14.1 above does not extend to
any Product that (i) is modified or altered, (ii) is not maintained to COM21's
maintenance recommendations, (iii) is operated in a manner other than that
specified by COM21, (iv) has its serial number removed or altered or (iv) is
treated with abuse, negligence or other improper treatment including, without
limitation, use outside the recommended environment), Siemens' sole remedy with
respect to any warranty or defect is as stated in Section 14.3 above. Siemens is
fully responsible for satisfaction of its End-Users and will be responsible for
all claims, damages, settlements, expenses and attorneys' fees incurred by COM21
with respect to Siemens' End-Users or their claims beyond COM21's above warranty
obligation to Siemens, except for product liability claims arising from a design
or manufacturing defect in an unmodified Product for which COM21 shall be
responsible.

            14.6 COM21 warrants to Siemens that the Documentation provided to
Siemens hereunder is the current version of the Documentation and is complete,
technically accurate and that COM21 is entitled to grant the rights under
Documentation in accordance with the terms of this Agreement. If Documentation
supplied by COM21 hereunder materially fails to conform with this 



                                      12.
     13

warranty, COM21 will, as Siemens' sole remedy, correct such Documentation
pursuant to the terms set forth in Exhibit E hereto

            14.7 SUBJECT TO THE INDEMNIFICATION SET FORTH IN SECTIONS 18.1 AND
18.2 AND THE WARRANTIES IN THIS SECTION 14, COM21 MAKES NO OTHER WARRANTIES WITH
RESPECT TO THE PRODUCTS, THE DOCUMENTATION OR ANY SERVICES AND DISCLAIMS ALL
OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. FURTHER, COM21 DOES NOT
WARRANT, GUARANTEE OR MAKE ANY REPRESENTATIONS REGARDING THE USE, OR THE RESULTS
OF THE USE, OF THE PRODUCTS OR DOCUMENTATION IN TERMS OF CORRECTNESS, ACCURACY,
RELIABILITY OR OTHERWISE.

            14.8 Siemens' Representations and Warranties. Except as expressly
and unambiguously provided herein, Siemens represents, warrants and agrees not
to modify, create any derivative work of, or include in any other software or
make any copies of the Software or any software or firmware contained in the
COM21 Products or copies or any portion thereof.

            15.   TECHNICAL APPROVAL BY AUTHORITIES

            15.1 For the purposes of this Article 15 the "Approval Authorities"
shall mean the body or bodies having responsibility for approving the Products
for connection to communications networks in any country, except the Excluded
Territory.

            15.2 The Products delivered by COM21 shall substantially comply with
the requirements of the Approval Authorities in the following countries:

  
                                          
Europe                                   Austria, Belgium, Denmark, France,
                                         Germany, Italy, Netherlands, Portugal,
                                         Spain, Switzerland

Asia                                     Taiwan

North America                            Canada, USA

South America                            Brazil, Chile, Colombia, Venezuela
  

            On Siemens' request COM21 shall make commercially reasonable efforts
to modify the Products to become compliant also with the requirements of the
Approval Authorities in other countries identified by Siemens. The details of
such modifications (including, without limitation, costs, schedule for
completion and scope of the modifications) will be agreed to between the parties
on a case by case basis.



                                      13.
     14

            16.   CANCELLATION/POSTPONEMENT OF ORDERS

            16.1 Siemens shall be entitled to cancel Orders wholly or partially
at any time by giving written notice to COM21. Except where the cancellation is
caused by reasons attributable to COM21 or attributable to Force Majeure, COM21
shall be entitled to the following payments (excluding any further claims
whatsoever) in connection with any cancellation of a Purchase Order by Siemens:

                  a) where notice of cancellation is given up to thirty (30)
days before the scheduled Delivery Time, the payments will be equivalent to
twenty percent (20%) of the value of the part of the Order(s) canceled; and

                  b) where notice of cancellation is given more than thirty (30)
days, but less than sixty (60) days, before the scheduled Delivery Time, the
Payment will be equivalent to ten percent (10%) of the value of the part of the
Order(s) canceled.

            16.2 Siemens may postpone the agreed delivery dates up to ninety
(90) days, at no charge, provided COM21 shall be notified of the postponement in
writing more than thirty (30) days before the Schedule Delivery time. However,
if an Order is postponed more than ninety (90) days or if it is postponed twice,
it will be deemed canceled.

            17.   TECHNICAL TRAINING AND SUPPORT

            17.1 Upon Siemens' request COM21 shall train experts of Siemens, its
Subsidiary Companies or End-Users in the installation, testing, commissioning,
operation, repairs and maintenance of the Products. Such training will be given
for each Product. COM21's trainers shall provide Siemens' trainees with adequate
training materials (training documentation and additional used material like CBT
or video clips), such materials being part of the Documentation. The details of
such training, e.g., date, duration, location, number of trainees, etc. will be
agreed upon by the parties on a case by case basis reasonably in advance. In any
event the training shall commence not later than four (4) weeks after Siemens'
request.

            All reasonable travel, meal and lodging expenses incurred by COM21
in connection with the training shall be borne by Siemens for training that is
conducted at Siemens' facilities. Siemens shall pay the fees stated. in Exhibit
A for all training exceeding ten (10) Siemens' trainees for each course.

            17.2 COM21 shall provide to Siemens a set of reproducible training
materials, in either tangible or electronic form, including such materials as
usually utilized by COM21 when instructing its own End Users (e.g., video clips)
for a onetime set-up fee of FIVE THOUSAND DOLLARS ($5,000). Such training
materials shall be in English and, if available, also in German. Siemens shall
be entitled to copy, modify (as long as the meaning of the content is not
changed) and 



                                      14.
     15

translate such training materials and to affix Siemens' copyright
notices, in addition to COM21's copyright notices, to any copy of such
materials. Siemens, its Subsidiary Companies and other sales outlets may utilize
any copy of COM21's training materials for performing its own training courses
for their own End-Users. Siemens shall make commercially reasonable efforts to
provide COM21 with one (1) copy of any and all modifications and translations
produced by Siemens of the training materials.

            17.3 COM21 shall provide second level support to Siemens of the
Products pursuant to the terms and conditions set forth in the COM21 Support
Terms and Conditions in Exhibit C hereto. Such support shall be at no expense to
Siemens, except that Siemens shall reimburse COM21 for all travel, lodging and
meal expenses of COM21 personnel performing on-site support at an End-User's
facility.

            17.4 COM21 shall, at Siemens' reasonable request, provide reasonable
support for Siemens' and its Subsidiary Companies' sales effort by, for example
and not by way of limitation, making presentations to Customers, providing
technical information concerning Products, supplying references and giving tours
of plant. During the first six (6) months of the Initial term, this support will
be provided at no additional cost to Siemens. Thereafter the Parties will agree
upon the amount payable by Siemens before the sales support services are
provided by Seller.

            18.   PATENT, COPYRIGHTS AND TRADEMARKS

            18.1 Siemens shall inform COM21 in writing without delay if a third
party brings a claim regarding the infringement of its protective rights (e.g.,
patent, trademark, copyright, mask work, trade secret or other similar rights)
by any of the Products.

            Siemens shall not concede the validity of, or settle, such a claim
from any third party without the prior written consent of COM21. COM21 shall
defend, indemnify and hold Siemens and its officers, directors. employees and
agents harmless from liability resulting from infringement by the Product of any
United States, European Community or Japanese patent or design patent issued as
of the first date of delivery to Siemens of the applicable Product or any United
States, European Community or Japanese copyright or infringement of any United
States or European Community trademark resulting from Siemens' use of the Marks
(as defined in Section 21) as permitted hereunder, provided COM21 is promptly
notified of any and all threats, claims and proceedings related thereto, given
reasonable assistance in connection therewith and has sole control over the
defense and all negotiations for a settlement or compromise; COM21 will not be
responsible for any settlement it does not approve in writing. The foregoing
obligation of COM21 does not apply with respect to any Product or portions or
components thereof (i) not supplied by COM21, (ii) made in whole or in part in
accordance to Siemens' specifications and where the infringement relates to
these specifications, (iii) which is modified after shipment by COM21, (iv)
combined with other products, processes or materials not supplied by COM21,
where the infringement relates to such combination, (v) where Siemens continues
allegedly infringing activity after being 



                                      15.
     16

notified thereof or after being informed of modifications that would have
avoided the alleged infringement, or (vi) where Siemens' use of the Product is
incident to an infringement not resulting primarily from the Product or is not
strictly in accordance with the licenses granted hereunder. Siemens will
indemnify COM21 and its officers, directors, employees and agents from all
damages, settlements, attorneys' fees and expenses related to a claim of
infringement excluded from COM21's indemnity obligation by the foregoing
sentence.

            18.2 In the event a Product is finally determined by a court of
competent jurisdiction to infringe the rights of a third party, COM21 shall be
obligated. at its sole option and cost, either:

                  a) to acquire from the third party entitled to dispose of the
respective protective rights, the right of use required for the purposes of this
Agreement; or

                  b) to replace such infringing Products or parts thereof by
non-infringing ones complying with COM21's published specifications for such
Product, which Siemens shall accept as full and complete satisfaction (subject
to indemnification under Section 18.1) for any claims it might have against
COM21 arising from such infringement.

            18.3 COM21's obligation of indemnification under Sections 18.1 and
18.2 with respect to liability from infringement of any third party European
Community or Japanese patent, design patent, copyright or trademark shall not
exceed the amount in aggregate paid to COM21 by Siemens for sales of the
Products in the country in which the infringement occurred during the twelve
(12) month period prior to the date such liability arose. For purposes of this
Agreement, a European Community patent, trademark and/or copyright is any such
statutory right that is enforceable in the territory of the European Community
and/or member states of the European Patent Convention.

            18.4  THE FOREGOING IS IN LIEU OF ANY WARRANTIES OF
NONINFRINGEMENT, WHICH ARE HEREBY DISCLAIMED.

            19.   TERMINATION AND PROVISIONS AFTER TERMINATION

            19.1 This Agreement may by written notice be forthwith terminated by
either party having such right as herein provided - and save of any other rights
such party may have-upon the occurrence of either one or more of the following 
events stated below:

                  a) by either party in the event that the other party
voluntarily files a petition in bankruptcy or has such a petition involuntarily
filed against it (which petition is not discharged within ninety (90) days after
filing), or is placed in an insolvency proceeding, or if an order is issued
appointing a receiver or trustee or a levy or attachment is made against a
substantial 



                                      16.
     17

portion of its assets which order shall not be vacated, or set aside within
ninety (90) days from date of issuance, or if any assignment for the benefit of
its creditors is made;

                  b) by either party in the event that the other has failed in
the performance of any material contractual obligation herein contained,
provided that such default is not remedied within sixty (60) days after written
notice to such party specifying the nature of such default and requiring remedy
of the same (except in the event of a breach of Sections 4.5, 14.8 or 20 in
which case termination shall be effective immediately upon notice);

                  c) if the other ceases to do business, or otherwise terminates
business operations; provided, however, that the acquisition of all or
substantially all of a party's stock, assets or business shall not be grounds
for termination of this Agreement; or

                  d) If the other shall fail to promptly secure or renew any
license, registration, permit, authorization or approval for this Agreement or
the conduct of its business in the manner contemplated by this Agreement or if
any such license, registration, permit, authorization or approval is revoked or
suspended and not reinstated within sixty (60) days.

            19.2 This Agreement may be terminated by COM21 with respect to a
Siemens Subsidiary Company immediately by written notice to Siemens upon the
occurrence of any of the following events:

                  a) In the event that the Subsidiary Company voluntarily files
a petition in bankruptcy or has such petition involuntarily filed against it
(which petition is not discharged within ninety (90) days after filing), or is
placed in an insolvency proceeding, or if an order is issued appointing a
receiver or trustee or a levy or attachment is made against a substantial
portion of its assets which order shall not be vacated, or set aside within
ninety (90) days from date of issuance, or if any assignment for the benefit of
its predictors is made;

                  b) In the event that the Subsidiary Company has failed in the
performance of any material contractual obligation herein contained, provided
that such default is not remedied within sixty (60) days after written notice to
such party specifying the nature of such default and requiring remedy of the
same (except in the event of a breach of Sections 4.5, 14.8 or 20 in which case
termination shall be effective immediately upon notice);

                  c) If the Subsidiary Company ceases to do business, or
otherwise terminates its business operations; provided, however, that the
acquisition of all or substantially all of the Subsidiary Company's stock,
assets or business shall not be grounds for termination of this Agreement; or

                  d) If the Subsidiary Company shall fail to promptly secure or
renew any license, registration, permit, authorization or approval for this
Agreement or the conduct of its 



                                      17.
     18

business in the manner contemplated by this Agreement or if any such license,
registration, permit, authorization or approval is revoked or suspended and not
reinstated within sixty (60) days.

            19.3 Except in the event of a termination by COM21 pursuant to
Section 19.1 (a) or (b), COM21 shall continue for a period of six (6) months
following termination of this Agreement, to supply to Siemens Products according
to the terms of this Agreement to such extent as required by Siemens to fulfill
all commitments to End-Users involving the Products which Siemens has undertaken
prior to notice of termination of this Agreement, provided that Siemens promptly
notifies COM21 in writing of such commitments.

            19.4 For a period of five (5) years after termination of this
Agreement, except in the event of a termination by COM21 pursuant to Section
19.1(a) or (b), COM21 shall supply to Siemens, in accordance with the terms and
conditions in effect at the time of termination of the Agreement, Products
required by Siemens for the expansion of the existing End-User systems in which
Products are already used, provided Siemens identifies in writing all End-Users
for whom such Products are required. If COM21 wishes to discontinue the
manufacture of such Products before the end of said five-year period after
termination or expiration of this Agreement, COM21 shall notify Siemens thereof
and the parties will mutually agree upon the terms.

            19.5 After termination of this Agreement, except in the event of a
termination by COM21 pursuant to Section 19.1(a) or (b), COM21 shall be obliged
to supply spare parts to Siemens for a period of seven (7) years after the last
delivery by COM21 to Siemens of the Products for which such spare parts are
used. Such supply shall be in accordance with the terms and conditions in effect
at the time of termination of this Agreement. After such seven (7) year period,
the parties shall consult with each other whether or not to continue this
obligation, on the terms to be mutually agreed upon by the parties, in
consideration of the quantity of remaining Products installed with Siemens'
End-Users.

            19.6 Termination is not the sole remedy under this Agreement and,
whether or not termination is effected, all other remedies will remain
available.

            19.7 Except as otherwise provided in Sections 19.2, 19.3 or 19.4,
upon any termination of this Agreement by COM21.

                  (i) All licenses granted to Siemens and Siemens Subsidiary
Companies hereunder shall immediately terminate, and Siemens shall discontinue
all distribution of the Products and use of the Marks; and

                  (ii) Siemens may keep one (1) copy of the Software in object
code form to be used solely for support of its installed base of Products as of
the date of termination and Siemens shall have a limited license only to the
extent necessary for Siemens to support the installed base of Products.



                                      18.
     19

            Except as otherwise provided herein, upon termination of this
Agreement, each party shall, within fifteen (15) days of the effective date of
any termination, return to the other or destroy all manifestations of the other
party's Confidential Information and any and all other materials in such party's
possession which had been furnished to it by the other party pursuant to this
Agreement, and such party shall warrant in writing to the other within thirty
(30) days after termination or expiration that all such materials have been
returned or destroyed.

            19.8 Termination of this Agreement shall not relieve Siemens and
COM21 from their obligations to pay any sums accrued and payable hereunder. The
parties agree that their respective rights, obligations and duties under
Sections 4.5, 4.6, 12, 14.7, 19.6, 19.7, 19.8, 20, and 25 39 as well as any
rights, obligations and duties which by their nature extend beyond the
termination or expiration of this Agreement shall survive any termination or
expiration of this Agreement.

            19.9 Each party understands that the rights of termination hereunder
are absolute. Neither party shall incur any liability whatsoever for any damage,
loss or expenses of any kind suffered or incurred by the other (or for any
compensation to the other) arising from or incident to any termination of this
Agreement by such party which complies with the terms of this Agreement whether
or not such party is aware of any such damage, loss or expenses.

            20.   CONFIDENTIAL INFORMATION

            20.1 Each party (the "Receiving Party") shall, at all times, both
during the term of this Agreement and thereafter for a period of five (5) years,
keep in confidence as a fiduciary all of the other party's (the "Disclosing
Party") Confidential Information received by the Receiving Party irrespective of
the medium such information or data is embedded. Such Confidential Information
has to be - when disclosed in tangible form - marked as "Confidential" or
similar legend by the Disclosing Party before disclosing to the Receiving Party
or has to be - when disclosed orally or visually - summarized in writing by the
Disclosing Party and said summary will be given to the Receiving Party within
thirty (30) days of the subject oral or visual disclosure. In case of
disagreement, the Receiving Party must make any objections to the contents of
the summary in writing within thirty (80) days of receipt. The Receiving Party
shall not use the Confidential Information of the Disclosing Party other than as
expressly permitted under the terms of this Agreement or by a separate written
agreement. The Receiving Party shall take all reasonable steps to prevent
unauthorized disclosure or use of the Disclosing Party's Confidential
information and to prevent it from falling into the public domain or into the
possession of unauthorized persons. The Receiving Party shall not disclose
Confidential Information of the Disclosing Party to any person or entity other
than its officers, employees, consultants and subsidiaries who need access to
such Confidential Information in order to perform its obligations under this
Agreement and who have entered into written confidentiality agreements which
protect the Confidential Information of the Disclosing Party. The Receiving
Party shall immediately give notice to the Disclosing Party of any unauthorized
use or disclosure of Disclosing Party's Confidential Information. The Receiving
Party 



                                      19.
     20

agrees to assist the Disclosing Party to remedy such unauthorized use or
disclosure of its Confidential Information. With regard to the Software, the
five (5) year limitation shall not apply. The obligations of confidentiality
shall not apply to any information the Receiving Party can document:

                  (i) is or becomes available to the public or to the industry
without the fault or negligence of the Receiving Party;

                  (ii) was in the possession of the Receiving Party prior to
disclosure by the Disclosing Party;

                  (iii) is subsequently lawfully received from a third party
without restriction on further disclosure;

                  (iv) has been independently developed by the Receiving Party
without use of the Disclosing Party's Confidential Information by employees or
agents who have not had any access to such Confidential Information;

                  (v) is not in writing and marked with a legend indicating the
same is proprietary, private or confidential, or if disclosed in non-tangible
form, is not summarized in writing and marked "Confidential" or "Proprietary"
within thirty (30) days of the Disclosing Party's disclosures; or

                  (vi) is required to be disclosed by any law or regulation, or
by the decree of any competent tribunal; provided that the Disclosing Party
shall limit its disclosure to the information required to be disclosed and shall
use its best efforts to provide the maximum possible notice to the other party
prior to such disclosure and assist such party in seeking protection of the
information to be disclosed.

            Notwithstanding anything to the contrary, the Software source code
and any and all firmware contained in the Products shall be deemed to be COM21's
Confidential Information disclosed to Siemens subject to the confidentially
restrictions of this Section 20.1.

            20.2 Both parties agree to treat the terms of this Agreement as
confidential under paragraph 20.1.

            21.   TRADEMARKS AND TRADE NAMES

            21.1 Siemens recognizes that COM21 is the owner of the trademarks
and trade names connoting COM21 which may elect to use in the promotion and sale
of the Products and that Siemens has no property rights or interest in or to
such trademarks and trade names.



                                      20.
     21

            21.2 COM21 and Siemens agree not to use each other's trademarks,
brand name, or logo in any manner, unless otherwise authorized in writing by the
other.

            21.3 Depending on the requirements for marketing to a particular
customer End-User or in a particular market, Cable Modem Products shall be
badged with all or any of the following trademarks, as may be set forth in an
Order:

                  a) COM21; or

                  b) Siemens; or

                  c) Any other trademark or designation mutually agreed upon by
the parties.

            Siemens is entitled to use COM21's trademarks (hereinafter referred
to as the "Marks") in advertisements, price lists, commercial notices, business
correspondence, cartons, packing, sales literature, manuals, displays and signs
relating to the Products. In case Siemens uses the marks Siemens will use all
commercially reasonable efforts to use the then current Marks used by COM21 for
the Products. Siemens will undertake to identify COM21 in written material
(e.g., in form of a footnote) as the owner of the Marks and shall obtain COM21's
prior written approval of all materials bearing a Mark, which approval will not
be unreasonably withheld. COM21 will be deemed to have approved such use if
Siemens does not receive notice of disapproval within ten (10) days after
COM21's receipt of a request for approval.

            21.4 Siemens acknowledges that the ownership of the Marks is in
COM21 and agrees that it will do nothing inconsistent with such ownership by
COM21 (including, without limitation, registration of any of the Marks without
COM21's prior written consent) and that any use of the Marks by Siemens shall
inure to the benefit of COM21.

            21.5 Siemens agrees that this Agreement does not give Siemens any
further right, title or interest than stated above to use the Marks and Siemens
undertakes - as far as legally permissible - not to attack the validity or title
of COM21 to the Marks nor assist anyone from doing so.

            21.6 Siemens shall not use during the lifetime of this Agreement any
trademark, product name, logo or other designation colorably imitating or
confusingly similar to any of the Marks.

            21.7 Siemens agrees that it will call to the attention of COM21 any
use of designations by any third party which Siemens reasonably considers might
be an infringement of a Mark. However, COM21 shall have the sole right to decide
whether or not proceedings shall be brought against such third parties at
COM21's expense. COM21 shall be entitled to any and all amounts awarded in such
proceedings. In any event, Siemens agrees to cooperate fully with COM21 



                                      21.
     22

to whatever extent necessary to prosecute such action, including, without
limitation, submitting proof of use and providing formal declarations with
regard to use of the Marks.

            21.8 On the request of Siemens, COM21 and Siemens will mutually
discuss and agree upon the filing of any application for trademark protection of
the Marks and the responsibility of each party for the costs of such filing.
COM21 will furnish Siemens with a complete list of all applications and
registrations for the Marks in order to put Siemens into a position to decide
whether or not additional trademark protection is required.

            22.   CHANGES TO PRODUCTS AND NEW PRODUCTS

            22.1 COM21 reserves the right to change or modify any Product at any
time only to the extent it does not materially adversely affect compliance of
such Product with the requirements stated in Article 15 and does not materially
adversely affect the form, fitness, functions, safety, reliability, performance
and/or maintainability of such Product detailed in the specifications set forth
in Exhibit A of this Agreement. If COM21 for whatever reason intends to make
technical changes to a Product, COM21 shall use commercially reasonable efforts
to notify Siemens at least ninety (90) days in advance, stating in writing the
type of changes, the reasons for them and the effects and consequences resulting
therefrom.

            All changes in respect of the Product must be substantiated by
sufficiently complete documentation commensurate with the nature of the change,
e.g., by a field change bulletin relating to engineering, manufacturing or
retrofitting.

            22.2 If Siemens, for whatever reason, requests technical changes to
a Product, COM21 and Siemens shall negotiate in good faith an agreement to
implement such changes. Changes of Products due to End-User fault reports
showing Epidemic Failures shall be provided by COM21 free, of charge. In the
event of an Epidemic Failure of a Product, COM21 will, within thirty (30) days
following COM21's confirmation of the existence of the Epidemic Failure, correct
such Epidemic Failure or provide Siemens with a written action plan for
correction of such Epidemic Failure.

            22.3 Changes to Products which are necessary due to End-User
requirements shall be implemented by COM21 subject to terms and conditions to be
mutually agreed upon in writing.

            22.4 Changes to Products affecting their compliance with the
requirements stated in Article 15 or their form, fitness, functions, safety,
reliability, performance and/or maintainability detailed in the specifications
set forth in Exhibit A of this Agreement shall be implemented by COM21 subject
to terms and conditions to be mutually agreed upon in writing.

            22.5 Regarding changes as per this Article 22, COM21 shall at its
own expense, and upon Siemens' request, submit to Siemens, as a bailee, free of
charge a minimum of three (3) 



                                      22.
     23

samples of modified Products for testing purposes for a reasonable period of
time to be agreed upon by Siemens and COM21. All Products furnished by COM21 to
Siemens under this Section 22.5 ("Bailed Property") shall: (i) be clearly marked
or tagged as COM21's property; (ii) be and remain personal property and not
become a fixture to real property; (iii) be subject to inspection by COM21 at
any time; (iv) be used only for testing by Siemens; (v) be kept free of liens
and encumbrances; (vi) be kept separate from other materials, tools or property
of or held by Siemens; (vii) not be modified in any manner by Siemens; and
(viii) shall be stored in a safe place and environment. In the event Siemens
uses the Bailed Property for any purpose other than to conduct testing as
specified herein without COM21's prior written consent, Siemens agrees to
purchase such Bailed Property at COM21's list price for such Bailed Property.
COM21 shall retain all rights, title and interest in and to the Bailed Property,
and Siemens agrees to treat and maintain the Bailed Property with at least the
same degree of care as Siemens uses with respect to its own valuable equipment.
Siemens shall bear all risk of loss or damage to the Bailed Property until it is
returned to COM21. After such tests Siemens shall, in its sole discretion, buy
or return the Bailed Property to COM21 in good condition, normal wear and tear
excepted. The cost of the return shipment shall be borne by COM21 if the change
is within the scope of Article 22.1, otherwise the cost of the return shipment
shall be borne by Siemens. Siemens waives any illegal or equitable right it may
have to withhold the Bailed Property and Siemens agrees to execute all documents
or instruments evidencing COM21's ownership of the Bailed Property and as COM21
may from time to time request.

            22.6 If during the term of this Agreement, COM21 intends to
introduce a new Product replacing Products or designed or fit to supersede the
Products, COM21 shall inform Siemens thereof as soon as possible, but in any
event not less than ninety (90) days prior to such introduction, and shall
transmit to Siemens the specifications of such new Product. Upon Siemens request
COM21 shall provide test samples of new products in accordance with Article 22.5
above. Siemens may request and COM21 shall upon such request substitute the
Products with new products at mutually agreed upon prices.

            22.7 COM21 reserves the right to discontinue any Product at any
time, provided that COM21 uses its best efforts to provide Siemens twelve (12)
months prior notice of discontinuation. Notwithstanding the above, if a
compatible Product is not commercially available from COM21, then Siemens may,
at its option, (a) elect to manufacture the discontinued Product pursuant to a
separate written agreement executed by the parties granting Siemens the right to
manufacture the Products or (b) elect to place a final purchase order for any
quantity of the discontinued Product to be supplied by COM21 in one or more
deliveries.

            23.   SAFETY SPECIFICATIONS/CE-LABEL

            COM21 represents and warrants that the Products conform to
applicable EC directives in the current revision:

            89/336/EEC



                                      23.
     24

            73/23/EEC
            91/263/EEC
            93/68/EEC
            92/31/EEC

            COM21 guarantees that the statements in the EC Declaration of
Conformity are correct and is responsible to affix the CE Mark pursuant to said
directives.

            COM21 shall reimburse Siemens for all expenses approved by COM21 in
writing and for all direct damages incurred by Siemens in connection with
noncompliance by COM21 with said EC directives including, but not limited to,
resulting from mandatory recalls of the Products or other immediately remedial
action, provided COM21 is promptly notified in writing of any such
non-compliance, COM21 is permitted to assume sole control of correcting such
non-compliant Products and Siemens uses its best efforts to mitigate its damages
resulting from such noncompliance of the Products.

            COM21 will remain in compliance with the current versions of the
European Community directives applicable to the Products, provided Siemens gives
COM21 reasonable prior, written notice of any changes to such directives of
which Siemens becomes aware, and further provided that COM21 shall have a
reasonable amount of time to make modifications to the affected Products in
order to comply with any such new or amended directives.

            24.   CENTURY COMPLIANCE

            24.1 When used in this Agreement with initial capital letters., the
following terms have the respective meanings given below:

            "Procured System" means the computer software, computer firmware,
computer hardware (whether general or special purpose), documentation, data, and
other similar or related items of the automated, computerized and software
system, or any component part thereof, as originally provided by COM21 to
Siemens pursuant to this Agreement, unmodified by any party other than COM21
pursuant hereto.

            "Calendar Related" refers to date values based on the Gregorian
calendar as defined in Encyclopaedia Britannica, 15th edition, 1982, page 602,
and to all uses of those date values described in the Procured System
documentation.

            "Date Data" means any Calendar Related data in the inclusive range
January 1, 1900 through December 31, 2050 that the Procured System uses in any
manner.



                                      24.
     25

            "System Date" means any Calendar Related date value in the inclusive
range from January 1, 1985 through December 31, 2035 (including the transition
between such values) that the Procured System will be able to use as its current
date while operating.

            "Century Compliant" means that the Procured System satisfies the
requirements set forth in Sections 1.2, 1.3, and 1.4 below.

            "Century Non-Compliant" means any failure of the Procured System to
be Century Compliant.

            24.2 COM21 represents that Calendar Related processing by the
Procured System of the Date Data or of any System Date will not cause the
Procured System to cease to operate substantially in accordance with the
Procured System documentation.

            24.3 COM21 further represents that all data fields for the Date Data
contained in the Procured System are four digit fields capable of indicating
century and millennium.

            24.4 COM21 further represents that no change in the System Date
(including the change from the year 1999 to the year 2000) will cause the
Procured System to cease to operate substantially in accordance with the
Procured System documentation.

            24.5 Notwithstanding any provision to the contrary set forth in this
Agreement, COM21 makes no representation or warranty that the Procured System
shall be Century Compliant when operating in conjunction with any computer
software, computer firmware, computer hardware, or any combination of the
foregoing supplied by third parties.

            24.6 This Section 1 shall survive the expiration or earlier
termination of this Agreement.

            24.7 Century Noncompliance Remedy. In the event that the Procured
System is Century Non-Compliant in any material respect, COM21 shall use
commercially reasonable efforts to modify or replace the Procured System, or
applicable component thereof, to correct the Century Noncompliance. If COM21 is
unable, through the use of commercially reasonable efforts, to modify or replace
the Procured System to correct the Century Noncompliance, COM21 shall refund to
Siemens the license fee paid by Siemens to COM21 hereunder. The remedy set forth
in this Section 2.0 shall be Siemens' sole remedy for Century Noncompliance of
the Procured System.

            24.8 Noncompliance Notice. In the event COM21 (i) becomes aware of a
Century Noncompliance in the Procured System or (ii) begins any significant
effort to conform the Procured System to any international, governmental,
industrial, or other standard (proposed or adopted) regarding Calendar Related
data and/or processing, COM21 shall promptly inform Siemens of same. 



                                      25.
     26

COM21 shall respond promptly and in reasonable detail to reasonable inquiries by
Siemens with respect to (i) any Century Noncompliance in the Procured System or
(ii) such standards.

            25.   FORCE MAJEURE

            Neither Party to this Agreement shall be held responsible for the
performance of any obligations under this Agreement (except payment obligations
and obligations under Section 20) provided such performance is hindered or
prevented by any circumstances of Force Majeure which are deemed to include war,
riot, strike, lockout, flood, earthquake or other natural catastrophes or
national or local Government regulations and provided the party frustrated
notifies the other party without delay in writing at the beginning and end of
any such circumstances. The party frustrated shall use every endeavor to
minimize the hindrance or prevention of such fulfillment. Upon the ending of
such circumstance, the frustrated party shall without delay resume the
fulfillment of its obligations including any obligations, the performance of
which was interrupted thereby.

            26.   EXPORTS

            COM21 shall not be obliged to perform deliveries, orders and other
obligations under this Agreement if that performance is hindered by the
applicable export laws and regulations of the European Community, the United
States of America or other countries.

            With respect to those Products which include materials or technology
originating from the United States of America, which COM21 will identify in the
individual delivery documents, Siemens agrees that it will comply with all
restrictions, export laws and regulations of the United States of America, or
foreign agency or authority, and not to export, or allow the export or reexport
of any Product, Confidential information or any direct product thereof in
violation of any such restrictions, laws or regulations, or, without all
required licenses and authorizations, to Cuba, Libya, North Korea, Iran, Iraq or
Rwanda or to any Group D:l or E:2 country (or any national of such country)
specified in the then current Supplement No. 1 to Part 774 of the U.S. Export
Administration Regulations (or any successor supplement or regulations).

            27.   LIMITED LIABILITY

            EXCEPT AS OTHERWISE PROVIDED BELOW, AND EXCEPT THAT CLAUSES (1) AND
(11) WILL NOT LIMIT SIEMENS' OBLIGATIONS OF INDEMNITY UNDER SECTION 4.1 OR 4.3
(EXCEPT AS OTHERWISE PROVIDED IN SECTIONS 4.1, AND 4.3) OR EITHER PARTY'S
OBLIGATIONS UNDER SECTION 18.1 OR 32, AND NOTWITHSTANDING ANYTHING ELSE IN THIS
AGREEMENT OR OTHERWISE, NO PARTY HERETO WILL BE LIABLE WITH RESPECT TO ANY
SUBJECT MATTER OF THIS AGREEMENT UNDER ANY CONTRACT, NEGLIGENCE, STRICT
LIABILITY OR OTHER LEGAL OR EQUITABLE THEORY FOR (I) ANY AMOUNTS IN EXCESS OF IN
THE AGGREGATE OF THE AMOUNTS PAID TO IT (IN THE CASE OF COM21) OR (IN THE 



                                      26.
     27

CASE OF SIEMENS) PAID OR OWED BY IT HEREUNDER DURING THE TWELVE (12) MONTH
PERIOD PRIOR TO DATE THE CAUSE OF ACTION AROSE, OR (II) ANY INCIDENTAL OR
CONSEQUENTIAL DAMAGES, LOST PROFITS OR LOST DATA OR (III) COST OF PROCUREMENT OF
SUBSTITUTE GOODS, TECHNOLOGY OR SERVICES. EACH PARTY SHALL HAVE NO LIABILITY FOR
ANY FAILURE OR DELAY DUE TO MATTERS BEYOND ITS REASONABLE CONTROL. THE
LIMITATIONS OF THIS SECTION 27 SHALL NOT APPLY TO A PARTY'S (I) BREACH OF
SECTION 20 OR (II) WILFUL ACTIONS OF SIEMENS, ITS SUBSIDIARY COMPANIES OR THIRD
PARTY DISTRIBUTORS APPOINTED BY SIEMENS BEYOND THE SCOPE OF ANY OF THE LICENSE
GRANTS HEREUNDER OR TO SIEMENS' (III) BREACH OF SECTION 4.5 OR 14.8.

            28.   SUBSTANTIVE LAW

            This Agreement shall be governed by and construed under the laws of
the State of New York and the United States of America without regard to
conflicts of laws provisions thereof and provisions providing for awards of
punitive damages and without regard to the United Nations Convention on
Contracts for the International Sale of Goods.

            Except that the parties shall be entitled to seek injunctive or
other equitable relief from a court pending arbitration to prevent irreparable
harm, any dispute, controversy, or claim arising out of or in relation to this
Agreement or at law, or the breach, termination or invalidity thereof shall be
finally settled by binding arbitration in accordance with the International
Rules of the American Arbitration Association ("AAA"), by three arbitrators, one
of which shall be appointed by COM21, of which shall be appointed by Siemens,
and one of which shall be appointed by the AAA. The place of arbitration shall
be Toronto, Canada and the arbitration proceedings shall be conducted in the
English language. The award rendered shall be final and binding upon each party
to this Agreement. Judgment upon the award may be entered in any court having
jurisdiction, or application may be made to such court for judicial acceptance
of the award and/or an order of enforcement as the case may be.

            29.   SEVERABILITY

            If any provisions of this Agreement shall be held invalid, illegal
or unenforceable, the validity, legality or enforceability of the remaining
provisions shall not in any way be affected or impaired thereby. COM21 and
Siemens shall use reasonable efforts to replace any invalid, illegal or
unenforceable provision by a legal, valid and enforceable provision which comes
as close as possible to the original intent of the parties,

            30.   NOTICES

            All notices under this Agreement must be in writing and sent by
confirmed telex or telecopy with written verification of successful
transmission, delivered by a major commercial 



                                      27.
     28

international rapid delivery service with tracking capabilities and written
verification of receipt, mailed by certified or registered mail, postage
prepaid, return receipt requested to a party at the address set forth below, or
at such other place of which the other part(ies) has notified in accordance with
the provision of this Section 29. If not received sooner, notice by mail shall
be deemed received five (5) days after deposit in the U.S. or German mails.

            If to COM21: COM21, Inc.

                          750 Tasman Drive
                          Milpitas, CA 94043
                          U.S.A.
                          Telecopy:  (408) 953-9299
                          Attention: President

            If to Siemens: Siemens AG

                          ON AN X
                          Hofmannstra(beta)e 51
                          D-81359 Munchen
                          Telecopy:  +49 89 - 722 - 21534
                          Attention:  Lothar Schmid
                                      General Manager Coax Products Subdivision

            With respect to any notices to COM21 pursuant to Section 19 above,
Siemens shall send a copy of such notice to:

                          Brobeck, Phleger & Harrison LLP
                          Two Embarcadero Place
                          2200 Geng Road
                          Palo Alto, CA 94303
                          Telecopy:   (415) 496-2885
                          Attention:  Thomas Kellerman, Esq.


            31.   INJUNCTIVE RELIEF

            It is expressly agreed that a material breach of this Agreement (a
breach of Section 20 shall be deemed a material breach of this Agreement) by a
party would cause irreparable harm to the non-breaching party and that a remedy
at law would be inadequate. Therefore, in addition to any and all remedies
available at law, the non-breaching party shall be entitled to seek an
injunction or other equitable remedies in all legal proceedings without
requirement of posting of any bond in the event of any threatened or actual
violations of any or all of the provisions hereof.

            32.   RELATIONSHIP OF THE PARTIES



                                      28.
     29

            The parties hereto expressly understand and agree that they are
independent contractors in the performance of each and every part of this
Agreement, and except as otherwise provided in this Agreement, are solely
responsible for all of their employees and agents and their labor costs and
expenses arising in connection therewith and are responsible for and will
indemnify each other from any and all claims, liabilities, damages, debts,
settlements, costs, attorneys' fees, expenses and liabilities of any type
whatsoever that may arise on account of their activities, or those of their
employees or agents (including, without limitation, direct and indirect
subdistributors) including, without limitation, providing or breaching
representations or warranties towards End-Users or failure to protect COM21's
ownership interest in the Products). COM21 is in no manner associated with or
otherwise connected with the distribution of Products by Siemens under this
Agreement, nor with Siemens' employment of other persons or incurring of other
expenses. Except as expressly provided herein, COM21 shall have no right to
exercise any control whatsoever over the activities or operations of Siemens.

            33.   ASSIGNMENT

            This Agreement and the rights hereunder are not transferable or
assignable by Siemens without the prior written consent of COM21. Any attempted
assignment, delegation or other transfer, of this Agreement or of any rights or
obligations hereunder contrary to this Section 32 shall be a material breach of
this Agreement by Siemens, shall be void and shall be of no force or effect.

            34.   SUCCESSORS AND ASSIGNS

            This Agreement shall inure to the benefit of, and be binding upon,
the parties and their respective successors and assigns.

            35.   REMEDIES

            Except as otherwise expressly stated in this Agreement, the rights
and remedies of a party set forth herein with respect to failure of the other to
comply with the terms of this Agreement (including, without limitation, rights
of termination of this Agreement) are not exclusive, the exercise thereof shall
not constitute an election of remedies and the aggrieved party shall in all
events be entitled to seek whatever additional remedies may be available in law
or in equity.

            36.   COUNTERPARTS

            This Agreement may be executed in two or more counterparts, each of
which be deemed an original, but all of which together shall constitute one and
the same instrument. If this Agreement is executed in counterparts, no signatory
hereto snail be bound until all the parties named below have duly executed or
caused to be duly executed a counterpart of this Agreement.



                                      29.
     30

            37.   ENTIRE AGREEMENT; MODIFICATIONS

            This Agreement, including any Exhibits and Addenda hereto,
constitutes the entire Agreement of the parties and supersedes all prior
communications, representations, agreements or understandings, either verbal or
written, between the parties with respect to the subject matter hereof. This
Agreement may not be altered, modified, amended or otherwise changed except by
supplemental written agreement signed by duly authorized officers of both
parties. In the event of any conflict between the terms contained in this
Agreement and the terms contained in any exhibit hereto, the terms of this
Agreement shall prevail.

            38.   WAIVER

            A waiver by either party of any default by the other party shall not
be deemed to be a continuing waiver or a waiver of any other default or of any
other provision of this Agreement, but shall apply solely to the instance to
which the waiver is directed.

            39.   CONSTRUCTION OF AGREEMENT

            This Agreement has been negotiated by the respective parties hereto
and their attorneys and the language hereof shall not be construed for or
against any party.

            40.   HEADINGS

            The section headings contained herein are for convenience of
reference only and shall not be used in interpreting or construing this
Agreement.



                                      30.
     31

            IN WITNESS WHEREOF, the parties hereto have executed this Agreement
as of the Effective Date.

COM21, INC.                         SIEMENS AG

By:                                 By:
   -----------------------------       -----------------------------------
Name:                               Name:
     ---------------------------         ---------------------------------
Title:                              Title:
      --------------------------          --------------------------------
Date:                               Date:
     ---------------------------         ---------------------------------
                                    By:                                   
                                       -----------------------------------
                                    Name:                                 
                                         ---------------------------------
                                    Title:                     
                                          --------------------------------
                                    Date:                                 
                                         ---------------------------------
                                    


                                      31.
     32


                                   EXHIBIT A

                     DESCRIPTION/SPECIFICATION OF PRODUCTS



                                    A-1.


     33

                                    EXHIBIT B

                       PRICES AND DISCOUNTS AS OF 12/2/97

            This Exhibit will be updated every [*] based upon the [*] stated in
section 8.1 of the contract.

COMPORT cable modems transfer price including Siemens discount:

  
                                  
CP1000      [*]
CP1100      [*]
  

COMCONTROLLER AND SOFTWARE

            The following headend hardware and software products [*] their
respective list prices excluding the headend support/spares kit:

  
                                                      
CC2100      ComCONTROLLER Ch/Sw/DPS/Tx/Rx/CC/EM (USD)
CC2100A     ComCONTROLLER Ch/Sw/DPS/Tx/Rx/CC/EM (USD)
CC2110      ComCONTROLLER Ch/Sw/DPS/Tx/Rx/CC/EM (Int'l)
CC2110A     ComCONTROLLER Ch/Sw/DPS/Tx/Rx/CC/EM (Int'l)
CC2101      ComCONTROLLER Ch/Sw/DPS/Tx/Rx/CC/EM (USD)
CC2111      ComCONTROLLER Ch/Sw/DPS/Tx/Rx/CC/EM (Int'l)
CC2102      ComCONTROLLER Ch/Sw/DPS/Tx/CC/EM (USD)
CC2112      ComCONTROLLER Ch/Sw/DPS/Tx/CC/EM (Int'l)
CC2120      ComCONTROLLER Expansion Chassis (USD)
CC2121      ComCONTROLLER Expansion Chassis (Int'l)
CC0101      ComCONTROLLER Tx RF Module
CC0100      ComCONTROLLER Transmit Main (US Domestic)
CC0110      ComCONTROLLER Transmit Main (International)
CC0200      comCONTROLLER Receive Card (US Domestic)
CC0210      comCONTROLLER Receive Card (International)
CC0300      ComCONTROLLER CC Card
CC0400      ComCONTROLLER 10BT Card (4K Addresses)
CC0401      ComCONTROLLER 10BT Card (8K Addresses)
CC0500      ComCONTROLLER ATM Switch (spare)
CC0520      ATM switch upgrade for CC2100/CC2110
CC0521      ATM switch upgrade for CC2100A/CC2110A
CC0600      ComCONTROLLER 110V/220V Power Supply (spare)
CC0700      ComCONTROLLER Mini-Chassis Back plane (spare)
CC0800      ComCONTROLLER Mini-Chassis Cabling, Assembly
CC0801      ComCONTROLLER Interconnect Module


  

[*] 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.
     34

  
                                     
CC0802      ComCONTROLLER ATM switch extender
CC0810      ComCONTROLLER Fan Assembly

CC0811      ComCONTROLLER Face Plate
CC0900      ComCONTROLLER Main Interconnect Module (MIM)
CC0901      ComCONTROLLER Expansion Interconnect Module (EIM)

SOFTWARE

CS3100      NMAPS Software License (US)
CS3000      NMAPS Software License (Int'l)
CS0300      HCX System Software License (US)
CS0310      HCX System Software License (International) 
CS3101      NMAPS Lite Software (US) 
CS3001      NMAPS Lite Software (Int'l) 
CS0101      NMAPS Software License Key for NMAPS Lite 
CS0102      NMAPS Network Management Application for NMAPS Lite 
CS0103      NMAPS Remote Web Based Management Application 
CS0104      HP Openview Entry Level Network Node Manager

NOTE: THE FOLLOWING COM21 SERVICES [*]

TRAINING, SUPPORT, SET PRICES AND WARRANTY PRICES 

CX9010      Off Site Support 
CX9020      On Site Support 
CX9025      System Installation 
CX9030      Technical Training (5 days)
CX9031      Technical Training (5 days) for more than 6 people 
CX9032      Technical Training at Reseller or End User facility 
CX9603      ComCONTROLLER Headend Support/Spares Kit (USD) 
CX9604      ComCONTROLLER Headend Support/Spares Kit (Int'l)
CX9100      12 month 24 hours x7 days Service Contract for ComCONTROLLER 
CX9200      12 month Extended Maintenance Contract for NMAPS and System Software at
            time of purchase
CX9201      12 month Extended Maintenance Contract for NMAPS Lite and System Software
            at time of purchase
CX9202      12 month Extended Maintenance Contract for NMAPS and System Software
            after time of shipment but before 12 month standard warranty expires
CX9203      12 month Extended Maintenance Contract for NMAPS Lite and System
            Software after time of shipment but before 12 month standard
            warranty expires
CX9500      ComPORT 24 Month Extended Warranty at time of purchase 
CX9550      ComPORT 24 Month Extended Warranty after time of shipment but before
            standard warranty expires
  

[*] 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. 

                                    B-2.

     35

  
                                                        
CX9510      ComCONTROLLER 24 Month Extended Warranty at time of purchase
CX9560      ComCONTROLLER 24 Month Extended Warranty after time of shipment but
            before standard warranty expires


DOCUMENTATION AND LITERATURE

CD8100      Technical Publication Set (CD8110, CD8120 and CD8140)
CD8110      Technical Reference Manual
CD8120      Installation, Operation and Maintenance Manual
CD8140      NMAPS Command Reference Manual
CD8141      NMAPS Quick Reference Guide
CD8151      ComPORT Quick Reference Guide
CD8500      Product Overview Brochure
CD8510      ComPORT Data Sheet
CD8520      ComCONTROLLER Data Sheet
CD8530      NMAPS Data Sheet

  

                                    B-3.


     36

                                  EXHIBIT C

                       COM21 SOFTWARE SUPPORT SERVICES

                             TERMS AND CONDITIONS

            The following terms and conditions relate to and are incorporated
into the Agreement. Capitalized terms not defined in Section 1 below have the
same meaning as in the Agreement.

1.    DEFINITIONS

      Unless defined otherwise herein, capitalized terms used in these Support
      Services Terms and Conditions shall have the same meaning as set forth in
      the Agreement.

      "Critical Error" means the Software crashes or a significant number of
      End-Users or single-key end-users of the Cable Modem Product are unable to
      use the Software because of replicatable Errors in the Software, causing
      significant inconvenience or dissatisfaction to such End-Users or
      end-users as the case may be.

      "Error" means an error in the Software which significantly degrades the
      Software's performance or function.

      "Error Correction" means the use of commercially diligent efforts to
      correct Errors.

      "Fix" means the repair or replacement of object or executable code
      versions of the Software to remedy an Error.

      "Minor Error" means that a small number of End-Users are experiencing a
      replicatable Error in the Software that limits some functionality of the
      Software or that Siemens' technical support personnel, after using
      commercially diligent efforts to provide a solution, require COM21's
      assistance.

      "Moderate Error" means End-Users are able to use the Software but a small
      number of End-Users experience Errors in the Software causing significant
      inconvenience to those End-Users due to some loss of functionality of the
      Software.

      "Support Services" means COM21 support services as described in Section 3.

      "Telephone Support" means technical support telephone assistance provided
      by COM21 to the Technical Support Contact during COM21's normal business
      hours.


     37

      "Workaround" means a change in the procedures followed or data supplied by
      Company to avoid an Error without substantially impairing use of Software
      by End-Users.

2.    COVERAGE

            Subject to the terms hereof, COM21 will provide Support Services to
Siemens for the Software.

3.    SUPPORT SERVICES

            Support Services consist of Error Correction as specified in Section
6 hereof provided to the "Technical Support Contact" designated by Siemens as
responsible for communications between the parties regarding the Support
Services hereunder. Upon detection of any Error, Siemens agrees to provide COM21
a listing of output and any other data, that COM21 may reasonably request in
order to reproduce the operating conditions similar to those present when the
Error occurred.

4.    FEES AND PAYMENT

            For Support Services after the Initial Term, Siemens shall pay COM21
the applicable Support Services fee as listed in the then-current COM21 price
list, Support Services fees will be billed on an annual basis, payable in
advance. Siemens shall be responsible for all taxes associated with Support
Services other than U.S. taxes based on COM21's net income. Siemens' payment is
due within thirty (30) days of receipt of COM21's invoice. In the event Siemens
fails to pay COM21 on the due date, then to reinstate or renew Support Services
(if allowed by COM21), Siemens must first pay COM21 the annual Support Services
fee and the reinstatement charge listed in the then-current COM21 price list.

5.    ERROR CORRECTION

            COM21 shall exercise commercially diligent efforts to correct any
Error reported by Siemens in the Software in accordance with the priority level
reasonably assigned to such Error by Siemens.

            a) Critical Errors. In the event of a Critical Error, COM21 will
respond to Critical Errors by assigning a technician to investigate the Error
within four (4) hours from the time Siemens reports the Error to COM21. COM21
will provide Siemens information and a proposal for the correction of such Error
no later than twenty-four (24) hours from the time the Error was first reported
to COM21. COM21 shall use its commercially reasonable efforts to provide a
Workaround or a Fix that solves or reduces the severity of the Error within 48
hours from the time Siemens first reports the Error. In the case where COM21 is
to provide a Fix, COM21 will do so ninety percent 


                                      C-2

     38

(90%) of the time within thirty (30) days following COM21's identification and
replication of the Error.

            b) Moderate Errors. In the event of a Moderate Error, COM21 will
respond to all Moderate Errors by assigning a technician to investigate such
Error within four (4) hours from the time Siemens reports the Error to COM21.
COM21 will provide a Workaround within fourteen (14) days or will Fix the Error
ninety percent (90%) of the time within ninety (90) days following COM21's
identification and replication of the Error.

            c) Minor Errors. In the event of a Minor Error, COM21 will respond
to requests for information within eight (8) hours and, if appropriate, use
commercially diligent efforts to provide an upgrade of the Software providing a
Workaround or a Fix for the Error within one hundred eighty (180) days of
Siemens' reporting of such Error.

            If COM21 believes that a problem reported by Siemens may not be due
to an Error in the Software, COM21 will so notify Siemens. At that time, Siemens
may (1) instruct COM21 to proceed with problem determination at its possible
expense as set forth below or (2) instruct COM21 that Siemens does not wish the
problem pursued at its possible expense. If Siemens requests that COM21 proceed
with problem determination at its possible expense and COM21 determines that the
error was not due to an Error in the Software, Siemens shall pay COM21, at
COM21's then-current and standard consulting rates, for all work performed in
connection with such determination, plus reasonable related expenses incurred
therewith. Siemens shall not be liable for (i) problem determination or repair
to the extent problems are due to Errors in the Software or (ii) work performed
under this paragraph in excess of its instructions or (iii) work performed after
Siemens has notified COM21 that it no longer wishes work on the problem
determination to be continued at its possible expense (such notice shall be
deemed given when actually received by COM21). If Siemens instructs COM21 that
it does not wish the problem pursued at its possible expense or if such
determination requires effort in excess of Siemens' instructions, COM21 may, at
its sole discretion, elect not to investigate the error with no liability
therefor.

6.    EXCLUSIONS

            COM21 shall have no obligation to support:

            a) Software that has been altered, damaged or modified or Software
or any portion thereof has been incorporated with or into other software; or

            b) COM21 software that is not the then current release or any
release which has been replaced by the then current release of the same
Software; or

            c) Problems in the Software that are caused by Siemens' negligence,
abuse or misapplication, misuse or other causes beyond the control of COM21.

                                    C-3.


     39

            COM21 shall have no liability for any changes in hardware (other
than the COM21 Headend Product or the Cable Modem Product) which may be
necessary to use the Software due to a Workaround.

7.    LIMITATION OF LIABILITY

            COM21's liability for damages from any cause of action whatsoever
relating to COM21's agreement to provide Support Services shall be limited to
ONE HUNDRED THOUSAND DOLLARS (US$100,000).

8. THESE TERMS AND CONDITIONS CONSTITUTE A SERVICE CONTRACT AND NOT A WARRANTY
FOR THE SOFTWARE. THE SOFTWARE AND ALL MATERIALS RELATED TO THE SOFTWARE ARE
SUBJECT EXCLUSIVELY TO THE WARRANTIES SET FORTH IN THE AGREEMENT. THIS EXHIBIT
IS AN ADDITIONAL PART OF THE AGREEMENT AND DOES NOT CHANGE OR SUPERSEDE ANY TERM
OF THE AGREEMENT EXCEPT TO THE EXTENT UNAMBIGUOUSLY CONTRARY THERETO.


                                    C-4.


     40
                                    EXHIBIT D

                        COM21 WARRANTY AND SERVICE POLICY

PURPOSE

            This document summarizes the terms and conditions of COM21 Warranty
and Service offerings for COM21 hardware and software products supplied to
reseller.

HARDWARE WARRANTIES

      STANDARD HARDWARE WARRANTY POLICY

            COM21 warrants that the hardware portion of the ComCONTROLLER and
ComPORT products will materially conform to the specifications applicable to
such product and will be free from material defects in materials and workmanship
under normal and proper use for one (1) year from the date of COM21's shipment.
COM21's sole liability under this warranty is, at the option of COM21, to repair
or replace a COM21 hardware product that does not conform with the foregoing
warranty. This warranty shall not apply any damage or defect arising as a result
of neglect, improper installation, alteration, accident, or improper use of a
COM21 hardware product. This warranty is specifically in lieu of, and COM21
disclaims, all other warranties, express or implied, including, without
limitation, any warranty for merchantability, fitness for a particular purpose
and non-infringement. COM21 will not be liable for any incidental or
consequential damages or for the cost of substitute goods, services or
technology.

            OTHER POLICY TERMS:

      -     ComCONTROLLER and ComPORT products are covered for twelve (12)
            months from date of COM21's shipment at no charge.

      -     $50 no trouble found charge for units that are returned, but are
            determined by COM21 to conform with the warranty.

      -     reseller pays shipping charges to COM21; COM21 pays return shipping
            charges unless no trouble found, then reseller pays return shipping
            charges unless otherwise agreed to by COM21.

      -     COM21 sends the repaired or replaced hardware units to reseller
            within fifteen (15) working days after COM21's receipt of the
            defective products covered under warranty unless otherwise agreed
            to.



     41

      -     A COM21 Return Material Authorization number must be obtained from
            COM21 Technical Support for all warranty and non-warranty repairs
            prior to return of hardware products.

            POST-WARRANTY HARDWARE EQUIPMENT SUPPORT

            After expiration of the one (1)-year hardware warranty period, COM21
will repair COM21 hardware products on a time and materials basis on the terms
and at the prices shown in the "COM21 Services" Section. COM21 will warrant such
out-of-warranty repair of COM21 hardware products for a period of ninety (90)
days from the date of COM21's shipment to reseller unless otherwise agreed to.

COMPORT EXTENDED WARRANTY

            The ComPORT extended warranty extends standard hardware warranty for
ComPORT cable modems and power supply for an additional twenty-four (24) months.
The price is [*] modem at time of purchase or [*] purchased before the standard
hardware warranty expires. This extended warranty cannot be renewed or further
extended.

COMCONTROLLER EXTENDED WARRANTY

            ComCONTROLLER extended warranty can be purchased for any
ComCONTROLLER product or sub-system and it extends standard hardware warranty
for an additional twenty-four (24) months. The warranty price is [*] of the
COM21 list price of theComCONTROLLER product or sub-system, if the warranty is
purchased at time of purchase, and is [*] if the warranty is purchased within
the twelve (12) month standard hardware warranty period. This extended warranty
cannot be renewed or further extended.

ORDER NUMBER AND PRICE OF HARDWARE WARRANTIES:

  
  
     Order        Description                                         Price
-----------------------------------------------------------------------------------
                                                                    
CX9500            ComPORT Extended Warranty (Time of                [*]    
                  purchase). Not renewable. No discounts are        
                  available

CX9550            ComPORT Extended Warranty (Within 12              [*]
                  months). Not renewable. No discounts are          
                  available

CX9510            ComCONTROLLER Extended Warranty (Time             [*]
                  of purchase).  Not renewable.  No discounts are    
                  available.


  

[*] 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. 

                                    D-2.

     42

  
                                                                                  
CX9560            ComCONTROLLER Extended Warranty (Within            [*]
                  12 months).  Nonrenewable.  No discounts are       
                  available.
  


SOFTWARE WARRANTY, SUPPORT AND MAINTENANCE CONTRACTS

       COM21'S SOFTWARE WARRANTY

             The warranty period for software media is ninety (90) days. The
COM21 software products are provided "as is" without warranty of any kind,
including, without limitation, any warranty of merchantability, fitness for a
particular purpose and non-infringement. Further, COM21 does not warrant,
guarantee, or make any representations regarding the use, or the results of the
use, of the licensed COM21 software products in terms of correctness, accuracy,
reliability, or that the licensed products are or will be error free unless
otherwise agreed to by COM21.

       SOFTWARE SUPPORT POLICY

             COM21 will provide telephone technical support for the current
shipping version of the COM21 software and its immediate prior release. For
example, if COM21 is shipping NMAPS v2.3, then COM21 would provide telephone
support for NMAPS v2.3 and version 2.2. If a customer was still using NMAPS
v2.1, COM21 would not provide support except to instruct the customer that it
must upgrade to the current shipping version, which in this case would be v2.3,
and then COM21 could determine if the customer's problem was resolved by the
current shipping release or if error still exists. If the error is not resolved
by the current shipping release, then COM21 would then provide technical support
to resolve or mitigate the error.

             COM21 will respond to Critical Errors by assigning a technician to
investigate the error within four (4) hours from the time customer reports the
error to COM21. COM21 will provide customer information and a proposal for the
correction of such error no later than twenty-four (24) hours from the time the
error was first reported to COM21. COM21 will use commercially reasonable
efforts to provide a Workaround within forty-eight (48) hours from the time
customer first reports the Error.

             COM21 will use its commercially reasonable efforts to provide
Workaround for moderate or minor errors within forty-eight (48) hours from the
time customer first reports the error to COM21, patches, i.e., software which
corrects or removes a reproducible anomaly or "bug", will not be provided for
these types of Errors. COM21 will use commercially reasonable efforts to correct
and/or fix moderate or minor errors in the next update or upgrade of COM21
software.

[*] 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. 


                                      D-3.


     43

       SOFTWARE MAINTENANCE CONTRACTS AND UPGRADES*

             Maintenance contracts for COM21 software have a twelve (12)-month
term beginning on the date of shipment by Com21, renewable annually.

             COM21 encourages its resellers to purchase software maintenance for
the COM21 software. The benefits of annual software maintenance are no-charge
upgrades including all new product features to all major releases of the COM21
software and all maintenance releases during the twelve (12) month term of the
maintenance contract. If purchased separately, the combined cost of these
upgrades and maintenance release will be more than the annual price of software
maintenance.

             COM21 encourages its resellers to offer customers the extended
software maintenance program with all others of COM21 software. The two examples
below illustrate the difference in price for maintenance of the COM21 software
with and without the extended software maintenance program in place.

a)     If a customer purchases a software maintenance contract at time of
       purchase of COM21 software. the price will be [*] of the list price of
       NMAPS and [*] of the list price of the System software (per
       ComCONTROLLER). Once the customer has purchased maintenance, it must
       purchase maintenance for all subsequent purchases of software and
       comCONTROLLER units in order for such software and ComCONTROLLER units to
       be covered under the maintenance program. For example, if a customer
       purchases NMAPS, one ComCONTROLLER including the System software and
       maintenance on 9/l/97, the software is covered until 8/31/98. If the
       customer purchases a new ComCONTROLLER including System software on
       12/1/97, it must purchase the maintenance for the System software. As a
       result, the NMAPS and System software that was purchased on 9/1/97 will
       be covered by the maintenance contract until 8/31/98 and the System
       software purchased on 12/1/97 will be covered by the maintenance contract
       until 11/30/98. If software maintenance is purchased after the date of
       purchase of the COM21 software, but within ninety (90) days, then the
       price is [*] of the list price of the COM21 software for which
       maintenance is purchased.

b)     A customer that does not purchase maintenance will receive maintenance
       (bug-fix) releases but not any upgrade or new feature of any component of
       the COM21 ComUNITY Access 


-------

*Major Release: A comprehensive software release that has significant new
                features to provide additional functionality or performance.

                     MAINTENANCE RELEASE: Periodic revisions to major releases
                     which may include performance improvements, support for new
                     hardware, new software features, and/or bug fixes.

[*] 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.

                                    D-4.

     44
     system. For example, an upgrade would be NMAPS or the System software
     moving from 2.1 to 2.2 or from 2.2 to 2.3. An example of a maintenance
     release would be moving from version 2.1 to 2.1.1. Under this scenario, if
     a customer purchased a new upgrade, it would pay [*] of the list price of
     the upgrade. Although for one upgrade, this price is less than the annual
     fee for maintenance purchasing two or more upgrades separately per year
     will cost more than the annual maintenance fee. COM21 is currently planning
     to release at least upgrades annually, who has purchased NMAPS v2.1 and
     does not purchase the upgrade to v2.2 charged [*] for the upgrade from
     v2.1 to v2.3.

ORDER NUMBER AND PRICE FOR SOFTWARE MAINTENANCE PRODUCTS:

  
  
  Order Number    Description                                       Price
  ------------    -----------                                       -----
                                                                                 
     CX9200       ComUNITY Access Software Maintenance           [*]
                  contract; includes free maintenance            
                  upgrades for a year (Time of purchase, per     
                  NMAPS and System Software License).            
                  Renewable

     CX9201       ComUNITY Access Software Maintenance           [*]
                  contract; includes free maintenance            
                  upgrades for a year (Time of purchase, per     
                  NMAPS Lite and System Software                 
                  License). Renewable

     CX9202       ComUNITY Access Software Maintenance           [*]
                  contract; includes free maintenance            
                  upgrades for a year (Within 90 days, per       
                  NMAPS and System Software License).            
                  Renewable

     CX9203       ComUNITY Access Software Maintenance           [*]
                  contract; includes free maintenance            
                  upgrades for a year (Within 90 days, per       
                  NMAPS Lite and System Software                 
                  License). Renewable
  

SERVICE OFFERINGS

       Standard Service Policy

             At no charge, COM21 offers the following support to reseller.

              -      (M-F) 7AM to 7PM PST telephone support, after hours message
                     support.

              -      Next business day response.

[*]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.

                                      D-5.
     45

              -      On site support requires a customer PO, minimum charge for
                     a service call is [*]



1      Order number, and price for service and service packages

  
  
  Order
  Number        Description                                    Price
-----------------------------------------------------------------------------
                                                                 
CX9010          Remote site support; 5 x 12 M-F                 [*]
                Technical Telephone Support (after 12
                month warranty period)
X9020          On site support, [*]                             [*]
                                                                [*]
                                  
CS9025          System installation rate, [*]                   [*]
                                                                [*]
                                          
  

Training and Support

COM21 offers the following training and support for its customers:

  
  
Order Number      Description                                         Price
-----------------------------------------------------------------------------------
                                                                          
CX9010            Remote site support; 5 x 12 M-F Technical           [*]
                  Telephone Support (after 12 month warranty
                  period)

CX9020            On site support,[*]                                 [*]
                                                                      [*]
                                  

CX9025            System installation rate, [*]                       [*]
                                                                      [*]    
                            

CX9030            Technical training (5 day train the trainer at      [*]        
                  COM21 facility) up to six attendees.


CX9031            Technical training (5 day train the trainer at      [*] 
                  COM21 facility) for 7-10 attendees.

CX9032            Technical training at customer facility (plus       [*] 
                  travel and living expenses billed at cost).
  

1 Support Packages


[*] 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.


                                      D-6.

     46

  
  
Order Number      Description                                      Price
----------------------------------------------------------------------------------
                                                                      
CX9603            North American Headend Support Kit              [*]
                  which includes one TxRF Module, one Tx
                  Main Module (56 bit DES encryption), one
                  Rx Module (56 bit DES encryption), one
                  CC Module, one Ethernet Module, and one
                  Fan Tray Assembly.  It does not include
                  Power Supply Module, or the ATM switch
                  fabric.  For these products to be used as
                  spares, contact COM21 for pricing.

CX9604            International Headend Support Kit which         [*]
                  includes one TxRF Module, one Tx Main Module 
                  (40 bit DES encryption), one Rx Module (40 bit 
                  DES encryption), one CC Module, one Ethernet
                  Module, and one Fan Tray Assembly. It does not
                  include Power Supply Module, or the ATM switch 
                  fabric. For these products to be used as spares, 
                  contact COM21 for pricing.
  


Note, that the North American and International Headend support kit does not
include Power Supply Module, or the ATM switch fabric. If customer/resellers
want to purchase the Power Supply Module and/or the ATM switch fabric as spares,
they need to contact COM21 for pricing.



COM21 ENCOURAGES ITS SALES FORCE TO OFFER CUSTOMERS THE ATM SWITCH FABRIC,
AND/OR POWER SUPPLY WITH THE HEADEND SUPPORT KIT. THE DISCOUNT FOR THE ATM
SWITCH FABRIC AND/OR POWER SUPPLY IS [*] OFF THEIR RESPECTIVE LIST PRICES.


[*] 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.
       

                             D-7.