Technology License and Reseller Agreement - 3Com Corp. and Com21 Inc.


                    TECHNOLOGY LICENSE AND RESELLER AGREEMENT


        This Technology License and Reseller Agreement is entered into by and
between 3Com Corporation, a California corporation with a principal place of
business at 5400 Bayfront Plaza, Santa Clara, California 95052 ('3Com'), and
Com21, Inc., a Delaware corporation with a principal place of business at 1991
Landings Drive, Mountain View, California 94043 ('Com2l'). The effective date of
this Agreement shall be the date last executed below ('Effective Date').


                                    RECITALS

        A. Com2l and 3Com intend to enable and drive deployment of broadband
services over Hybrid Fiber Coax (HFC) networks. The companies believe that
combining the parties' respective core competencies will enable the faster
introduction of HFC communications products to the market. Com2l's HFC
experience coupled with 3Com networking experience and broad product offering
will result in a more robust solution.

        B. Com2l or its suppliers are the owners of certain subscriber equipment
technology related to broadband services over Hybrid Fiber Coax (HFC) networks,
as more particularly described in Exhibit A (Com2l Technology).

        C. 3Com wishes to obtain a non-exclusive license for such technology in
order to develop, manufacture and market cable modems based on the Com2l
Technology. Com2l is willing to grant 3Com a technology license upon the terms
and conditions set forth below.

        D. Com2l intends to develop a data over cable headend distribution
system with assistance from 3Com. The first generation of such headend will
comply with the Specifications (as defined below) attached to this Agreement as
Exhibit B (Specifications). Com2l will permit 3Com to resell such headend on the
terms and conditions set forth herein.

        E. The parties also envision that 3Com will make an equity investment in
Com2l, under terms and conditions to be negotiated and documented in agreements
separate from this Agreement.

                                    AGREEMENT

        NOW, THEREFORE, the parties agree as follows:

1.      DEFINITIONS

        1.1 'Com2l Technology' means the Com2l first generation cable modem
technology (known as 'P3' and to be defined in the Design Package) (excluding
use of the expansion bus for optional plug-in modules) including, without
limitation, system design, behavioral code,

                                        1





ASICs and firmware, know-how, trade secrets rights, copyright rights, mask work
rights and, if any, rights under Com21 Patents owned, acquired, developed by or
licensed to Com21 and embodied in a cable modem product meeting the
Specifications. Com21 Technology also includes the technology necessary to
interface the 3Com Products to the Com21 Headend, and such other technology as
described on Exhibit A (Com21 Technology).

        1.2 'Com21 Headend' means the headend controller unit to be developed by
Com21, and all enhancements, upgrades and new versions thereof. The first
generation Com21 Headend shall implement the Specifications as they exist as of
the Effective Date together with such changes to the Specifications as the
parties mutually agree in writing.

        1.3 'Specifications' means the document entitled 'The Com21 Community
Protocol for HFC Networks, Revision 1.04 Branch 01 (V1.04.01), attached hereto
as Exhibit B (Specifications) and to be included in the Design Package. Updates
and revisions to the Specifications will be identified by a new branch index.
3Com shall be provided reasonable notice of and be permitted to attend Com21's
meetings regarding updates and/or revisions to the Specifications.

        1.4 'Com21 Mongoose Product' means Com21's modem ASIC (currently known
as Mongoose) implementing the media access control and other modem functions,
but excluding use of the expansion bus for optional plug-in modules, (i) as
described in the Com21 modem design specification attached as Exhibit C (Com21
Mongoose Product Specification), which specification may be changed from time to
time by Com21, in its sole discretion, with written notice to 3Com and (ii)
meeting certain criteria to determine the acceptability of the Com21 Mongoose
Product to be agreed to by the parties, which criteria shall be set forth in a
description attached to this Agreement as Exhibit D (Com21 Mongoose Product
Acceptance Criteria). The Com21 Mongoose Product Specification shall be provided
by Com21 within sixty (60) days of the Effective Date. The Com21 Mongoose
Product Acceptance Criteria shall be mutually agreed to by the parties within
sixty (60) days of the Effective Date.

        1.5 'Com21 P4 Product' means Com21's second generation modem ASIC
(currently known as P4) implementing the media access control and other modem
functions to be developed with AMD pursuant to a strategic partner relationship.

        1.6 'Com21 Patents' means all U.S. patents (and any foreign
counterparts), pending patent applications and any reissues, continuations,
divisions or extensions of such patents or applications, as to which Com21 is
the patentee or as to which Com21 has the right to grant the license herein and
which are necessary to practice the rights to the Com21 Technology, Com21
Mongoose Product and Com21 Headend interfaces which are granted herein.

        1.7 'Confidential Information' means that information of either party
('Disclosing Party') which is disclosed to the other party ('Receiving Party')
pursuant to this Agreement,

                                        2





in written form and marked 'Confidential' or if disclosed orally, the Disclosing
Party shall indicate that such information is confidential at the time of
disclosure and send a written summary of such information to the Receiving Party
within thirty (30) days of disclosure and mark such summary 'Confidential.'
Confidential Information shall include, but not be limited to, trade secrets,
know-how, inventions, techniques, processes, algorithms, software programs,
schematics, designs, contracts, customer lists, financial information, sales and
marketing plans and business information. References to 3Com as a Receiving
Party or a Disclosing Party shall also include all present and future subsidiary
and parent companies of 3Com.

        1.8 'Design Package' means the information and materials necessary to
develop cable modem products compatible with the Com21 Headend and the
Specifications. As set forth in detail in Section 5 (Design Package), the
description of the Design Package shall be attached to this Agreement as Exhibit
E (Design Package) when it is completed.

        1.9 '3Com Patents' means all U.S. patents (and any foreign
counterparts), pending patent applications and any reissues, continuations,
divisions or extensions of such patents or applications, as to which 3Com is the
patentee or as to which 3Com has the right to grant the license herein and which
are necessary to practice the rights to the 3Com Technology which are granted
herein.

        1.10 '3Com Product' means the cable modem products developed by 3Com
under the terms of this Agreement. 'First Generation 3Com Product' means the
first version of the commercially available low-cost data over cable 3Com
Product developed by 3Com as described in Section 2.3(a)(iii), 'Derivative 3Com
Products' means all 3Com Products other than the First Generation 3Com Product.

        1.11 '3Com Technology' shall mean the technology, including know-how,
trade secrets, copyrights and, if any, 3Com Patents, owned, acquired or
developed by or licensed to 3Com and embodied in the First Generation 3Com
Product.

2.      LICENSES

        2.1 Development and Manufacturing License. Subject to the terms and
conditions of this Agreement, Com21 hereby grants to 3Com a non-exclusive,
non-transferable, worldwide, royalty bearing license under the Com21 Technology
and Com21 Mongoose Product to (a) design, develop, make or have made, use,
market, sell, modify, lease and support 3Com Products, (b) design, develop, make
or have made, use, market, sell, modify, lease and support derivative cable
modem products based upon the 3Com Products, (c) sublicense its rights in the
Com21 Technology embodied in the Com21 Mongoose Product only granted in (a)
above, subject to the restrictions set forth in Section 2.3 (3Com Restrictions)
below and (d) reproduce and translate the materials in the Design Package
pursuant to the terms hereof as necessary for the exercise of the rights granted
in clauses (a) and (b) of this Section 2.1 (Development and Manufacturing
License).




*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.


                                        3





        2.2 Trademark License. Com21 hereby grants to 3Com a worldwide,
nonexclusive, limited license to use the Com21 trademarks, and the respective
stylistic marks, listed on Exhibit F (Com21 Trademarks) and such other mutually
agreeable Com21 marks (collectively, the 'Com21 Trademarks') in conjunction with
the distribution of the 3Com Products and in 3Com advertising, promotional and
printed materials for the 3Com Products. 3Com has provided to Com21 a copy of
the 3Com Trademark Guidelines. 3Com shall use the Com21 Trademarks in the manner
specified in the 3Com Trademark Guidelines for proper usage of 3Com trademarks.
The 3Com Trademark Guidelines may be modified from time to time by 3Com, in its
sole discretion, with written notice of such modification to Com21. in the event
Com21 implements its own trademark guidelines or policies, 3Com agrees to comply
with such guidelines or policies. If compliance with a Com21 policy or guideline
is not reasonably feasible, 3Com shall notify Com21 in writing and propose an
alternative procedure for Com21's approval, which will not be unreasonably
denied. Upon Com21's request, 3Com shall provide Com21 with free samples of the
3Com advertising and promotional materials and reasonable numbers of the 3Com
Product manufactured and distributed by 3Com on which such trademarks are used
to ensure that Com21's quality standards are maintained.

        2.3    3Com Restrictions.

               (a) Notwithstanding the foregoing licenses granted to 3Com in
this Section 2 (Licenses), (i) 3Com shall not have the right to sublicense to
any third party (except to 3Com present and future subsidiaries) the Com21
Technology licensed from Com21 before the second anniversary of the Effective
Date or until the Com21 P4 Product is available, provided, however, Com21 agrees
to support 3Com's discussions with third party manufacturers or vendors of
physical layer semiconductors regarding the inclusion of the Com21 Technology,
or any portion thereof, into such third party's products, (ii) until the third
anniversary of the Effective Date, 3Com shall not sell or make available for
sale as stand-alone products (i.e., not integrated into a card or system level
product) semiconductor chips designed by or on behalf of 3Com based on the Com21
Technology and (iii) 3Com will constrain the development and design of the First
Generation 3Com Product to low-cost, data over cable modems based on the Com21
Technology using RF technology compatible with the Com21 Headend.

               (b) As of the Effective Date, 3Com currently does not intend to
enter the market for Headend Controller Units for the future foreseeable (no
more than two years from the Effective Date). 3Com agrees to notify Com21 in
writing within a reasonable time in the event 3Com decides (which decision shall
be in 3Com's sole discretion) to begin development of a Headend Controller Unit.

        For purposes of this Section 2.3(b) only, 'Headend Controller Unit'
shall mean that piece of equipment that physically connects the cable modem to
the Headend via a hybrid fiber/coax or all coax network and is comprised of the
following: Upstream and downstream physical layer connections, Media Access
Controller (MAC), management interface that manages the MAC and physical layers
and provides application management and traffic scheduling and interface to
other equipment in the Headend.


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

                                        4





        For purposes of this Section 2.3(b) only, a 'Headend' shall mean the
office/wiring equipment that is directly connected to the cable modem via a
hybrid fiber/coax or all coax network. A Headend that is capable of offering
data services can be comprised of the following equipment: Headend Controller
Unit, switches, routers, network management, servers and other equipment that
may be necessary or desirable to offer data services (such as hubs, adapters,
and CSU/DSUs). The equipment outlined above may be in the form of separate
systems connected together via standard or proprietary interfaces. Alternatively
the functions may be contained in a single system or chassis comprised of cards
or plug-in-modules.

        2.4 Com21 Restriction. Com21 currently intends for 3Com to be its
primary cable modem Partner. As of the Effective Date, Com21 currently does not
intend to enter into an agreement containing technology rights similar to the
Com21 Technology rights granted in this Agreement with any other company for the
future foreseeable (no more than two years from the Effective Date). Com21
agrees to notify 3Com in writing within a reasonable time in the event 3Com
decides (which decision shall be in Com21's sole discretion) to enter into such
an agreement.

        2.5 3Com License to Com21. If Com21 desires, 3Com will grant to Com21 a
non-exclusive, non-transferable, worldwide, royalty-bearing license under the
3Com Technology to (a) make or have made, use, market, sell, modify, lease and
support the First Generation 3Com Products and (b) design, develop, make or have
made use, market, sell, modify, lease and support derivative cable modem
products based upon the First Generation 3Com Products. Com21 shall pay to 3Com
a reasonable royalty to be negotiated, and Sections 3.4 (Reports) and 4 (Payment
Terms) shall apply to Com21 on a reciprocal basis. If Com21 desires, 3Com agrees
to negotiate in good faith terms and conditions favorable to Com21 for Com21 to
OEM the First Generation 3Com Product. Upon Com21's election of the license
granted under this Section 2.5 (3Com License to Com21) and finalization of the
terms of such license, 3Com shall provide to Com21 a design package comprising
the information and materials necessary to develop the First Generation 3Com
Product (the '3Com Design Package') and the parties shall work together in good
faith to develop criteria to determine if such materials and information shall
be deemed acceptable.

        2.6 No Other Licenses. Except as specifically and unambiguously set
forth in this Agreement, no other licenses are granted by Com21 or 3Com to the
other party.

3.      LICENSE FEES, ROYALTIES AND REPORTS

        3.1 License Fee and Royalties. 3Com shall pay to Com21 the license fees
and royalties as set forth in this Section 3.1 (License Fee and Royalties).

               (a) Provided Com21 delivers to 3Com the existing portions of the
Design Package pursuant to Section 5.2 (Delivery) below, within thirty (30) days
of the Effective Date, 3Com shall pay to Com21 a one-time license fee of One
Million Dollars ($1,000,000).


*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.

                                        5


               (b) Concurrent with the payment described in Section 3.1(a), 3Com
shall also pay to Com21 a pre-paid, non-refundable (except in the event of a
refund pursuant to Section 5.4 (Remedies for Rejection and Termination) below)
royalty of One Million Dollars ($1,000,000) for the first 100,000 units of the
3Com Products to be sold by 3Com.

               (c) Until the earlier to occur of (i) the public availability of
the Com21 P4 Product in production quantities or (ii) December 31, 1998, 3Com
shall pay to Com21 a per unit royalty of [*] for units of 3Com Products for
which royalties are due in excess of one hundred thousand (100,000) sold by
3Com. Thereafter, no further royalties on 3Com Products shall be owed by 3Com to
Com21.

               (d) Notwithstanding clauses (b) and (c) above, no royalty shall
be due with respect to units of the 3Com Products for 3Com internal use, alpha
or beta units, demonstration units, consigned units, repair or replacement of
any 3Com Products, or the sale of spare parts on the performance of warranty
work for any 3Com Products.

        3.2 Mongoose Availability. If, on or before August 31, 1996, the Com21
Mongoose Product meeting the criteria to be agreed to by the parties and
described in Exhibit C (Com21 Mongoose Product Specification) and Exhibit D
(Com21 Mongoose Product Acceptance Criteria) is delivered by Com21 and which
meets or is later found to meet the Com21 Mongoose Product Acceptance Criteria
described in Exhibit D (Com21 Mongoose Product Acceptance Criteria), 3Com shall
pay to Com21 within thirty (30) days of acceptance by 3Com an additional
extended license fee of One Million Dollars ($1,000,000). If, after August 31,
1996 but on or before December 31, 1996, the Com21 Mongoose Product meeting the
criteria to be agreed to by the parties and described in Exhibit C (Com21
Mongoose Product Specification) and Exhibit D (Com21 Mongoose Product Acceptance
Criteria) is delivered by Com21 and which meets or is later found to meet the
Com21 Mongoose Product Acceptance Criteria described in Exhibit D (Com21
Mongoose Product Acceptance Criteria), said license fee shall be Five Hundred
Thousand Dollars ($500,000). If said Com21 Mongoose Product meeting said
criteria is not delivered by Com21 until January 1, 1997 or later, 3Com shall
not be obligated to make any license fee pursuant to this Section 3.2 (Mongoose
Availability); however, Com21 shall remain obligated to provide the Com21
Mongoose Product as provided this Agreement. Com21 shall provide 3Com a
reasonable number of samples of the Com21 Mongoose Product (including but not
limited to behavioral code) as it exists as of August 31, 1996 (regardless of
whether the Com21 Mongoose Product meets said criteria) and as it exists as of
the other dates set forth in this Section 3.2 (Mongoose Availability) until it
meets said criteria. 3Com agrees that COM 21 shall have no obligation to make
any modification or enhancement to the Com21 Mongoose Product to accommodate any
change in the 3Com Product.

        3.3 Most Favored Customer. Com21 represents and warrants that at the
date of this Agreement the license fees set forth herein do not exceed those
charged to any other customer of Com21 licensing the Com21 Technology or
technology similar or equivalent thereto. If at any time, Com21 offers lower
prices to any other customer for such similar or equivalent technology on
similar terms or on terms less favorable to Com21, taken as whole, Com21 shall
immediately





*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









notify 3Com and offer such more favorable license fees to 3Com effective as of
the date such prices were offered to such other customer.

        3.4 Reports. 3Com shall keep adequate records to verify all reports and
payments to be made to Com21 pursuant to this Agreement for a period of three
(3) years following the date of such reports and payments. Com21 shall have the
right to select an independent certified public accountant mutually agreeable to
the parties, whose fees are not contingent on the results of the inspection and
who agrees in writing to maintain the confidentiality of the information
provided to it, to inspect no more frequently than annually the records of 3Com
on reasonable notice and during regular business hours to verify the reports and
payments required hereunder. If such inspection should disclose any
underpayment, 3Com shall promptly pay Com21 such amount. The entire cost of such
inspection shall be borne by Com21; provided, however, that if 3Com is
determined by such audit to have underpaid royalties by five percent (5%) or
more, then the reasonable cost of such audit shall be home by 3Com.

4.      PAYMENT TERMS

        4.1 Payment. Per-unit royalties under Section 3.1(c) above shall accrue
upon shipment to a customer of 3Com Products by 3Com and shall be payable
quarterly, within thirty (30) days after the first day of the month following
the 3Com fiscal quarter in which royalties accrued. Each royalty payment shall
be accompanied by a statement of all units shipped during the relevant period
for which a royalty is due. Payments and statements shall be sent to Com21 at
the address set forth at the beginning of this Agreement or such other address
as Com21 may designate in writing.

        4.2 Taxes. In addition to any other payments due under this Agreement,
3Com agrees to pay, indemnify and hold Com21 harmless from any sales, use,
excise, import or export, value added or similar tax or duty, any other tax not
based on Com21's net income, and all governmental permit fees, license fees,
customs fees and similar fees which Com21 may incur in respect of this
Agreement.

5.      DESIGN PACKAGE

        5.1 Definition of Design Package. Promptly following the Effective Date,
the parties shall work together to determine and describe the materials and
information necessary to develop cable modem products compatible with the Com21
Headend and the Specifications, and the criteria to determine if such materials
and information shall be deemed acceptable. The description of the Design
Package shall be attached to this Agreement as Exhibit E (Design Package) when
it is completed. Com21 shall provide 3Com with updated versions of the Design
Package as it evolves during the course of design reviews by the parties.

        5.2 Delivery. On the Effective Date, Com21 shall deliver to 3Com all
then existing portions of the Design Package. In addition, Com21 shall use
commercially reasonable efforts to provide 3Com with the deliverables described
in the Design Package in accordance with the

                                        7





milestone schedule set forth therein. Because Com21's performance is dependent
in part on 3Com's performance, any dates or time periods relevant to performance
by Com21 hereunder shall be appropriately and equitably extended to account for
any delays due to 3Com.

        5.3 Acceptance. 3Com shall have twenty (20) days after receipt of each
deliverable in the Design Package (the 'Acceptance Period') to examine such
deliverable to determine that it substantially conforms with the Specifications
in Exhibit B (Specifications) and as described in Exhibit A (Com21 Technology).
3Com may reject a deliverable only if the deliverable fails in some material
respect to meet the Specifications in Exhibit B (Specifications) and as
described in Exhibit A (Com21 Technology). 3Com shall promptly notify Com21 if
it rejects such deliverable with a written summary of the reason for rejection.
If no written rejection is received by Com21 within the Acceptance Period, such
deliverable shall be deemed accepted. Should the delivery of the deliverable be
rejected by 3Com, Com21 shall use commercially reasonable efforts to correct the
deliverable to conform with the associated specifications and redeliver such
corrected deliverable to 3Com within twenty (20) days of receipt of rejection.
3Com will have twenty (20) days after receipt of the redelivered deliverable to
accept the deliverable. The foregoing acceptance/rejection/correction provisions
shall apply to a redelivered deliverable, provided, however, that upon the third
or any subsequent rejection, either party may terminate this Agreement by thirty
(30) days notice unless the deliverable is accepted during the notice period.
Com21 shall not be obligated to correct any failure caused by something other
than the deliverable.

        5.4 Remedies for Rejection and Termination. If this Agreement is
terminated pursuant to Section 5.3 (Acceptance) above, the parties agree to
negotiate in good faith the effect of such termination with respect to the
refund by Com21 of any amounts already paid by 3Com under Section 3 (License
Fees, Royalties and Reports) above, the portions of the Design Package, if any,
to be retained by 3Com and 3Com's right, if any, in such Design Package portions
and license fees in connection therewith. If the parties fail to agree on such
terms within thirty (30) days of the effective date of termination, Com21 shall
refund all amounts already paid by 3Com under Section 3 (License Fees, Royalties
and Reports) and 3Com shall have no rights in the Com21 Technology, the Com21
Mongoose Product or the Design Package.

6.      SUPPORT

        6.1 Design Support. Com21 will provide 3Com with a reasonable number of
man-hours of Com21 R&D, manufacturing and quality assurance engineers for
support by telephone, fax or if requested by 3Com, at 3Com Santa Clara site,
provided Com21's current timetable for commercialization is not adversely
impacted. Com21 and 3Com shall designate representatives to serve as contacts
for such support. If additional support is requested by 3Com, Com21 shall
provide, at Com21's sole discretion, such service at reasonable times and places
and at a rate equal to Com21's then current standard fee therefor (currently
[$150]/hour at Com21 facilities). Com21 shall provide 3Com with reasonable
advance notice of Com21 design reviews relating to Com21 cable modem products
and permit a 3Com representative to attend.





*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.



                                        8
                                   
                                           






        6.2 Customer Support. The parties agree to work together to develop and
facilitate the call handling processes to provide seamless customer support and
technical service to end users and service providers. Each party shall be solely
responsible for support of its products.

        6.3 3Com Support.

        3Com shall provide Com21 with a reasonable number of man-hours of the
following types of assistance:

                      (a)    Chip design expertise;

                      (b)    DVT facilities;

                      (c)    Physical layer certification assistance;

                      (d)    ATM switching technology;

                      (e)    Network management;

                      (f)    Low-cost volume manufacturing expertise; and

                      (g)    Other consulting advice.

Com21 shall provide to 3Com all the necessary technology to interface the 3Com
Products to the Com21 Headend.

7.      MARKETING

3Com and Com21 intend to jointly develop a marketing campaign to successfully
promote communication over HFC and remove adoption barriers for both MSOs and
end users. 3Com and Com21 shall jointly promote the Specifications to drive
industry standards. The parties envision that they initially would both market
the 3Com Product. The parties will work together to leverage their respective
relationships with MSOs to establish the superiority of the system solution they
jointly develop. The parties will work together to include each other products,
as appropriate and applicable, in their respective advertising, public relations
activities, tradeshows, product literature and manuals, and World Wide Web
sites.

8.      STANDARDS

The parties acknowledge and agree that it is in their mutual interests to
promote the 'The UPSTREAMS Protocol for HFC Networks' proposal, based on IEEE
802 contribution IEEE P802.14/95-152R1 (the 'Proposal') including subsequent
revisions, generated as required to promote acceptance in the standards bodies,
and ATM Forum contribution ATMF/95-1435R1, for acceptance in industry standards
with relevant standards bodies. The parties shall use

                                        9
                                   
                                           





reasonable efforts to collaborate on such promotion.

The parties further agree that other companies or consortia may participate in
efforts to promote the Proposal, as needed to build consensus within the
relevant standards bodies, and that additional contributors shall not be
precluded from being added to The Proposal in the future.

The Proposal shall be made freely available, but intellectual property rights
(including, without limitation, patent rights) included or referenced in the
Proposal shall be released or licensed in accordance with the policies of the
relevant standards body. Each shall retain all ownership of and title to
intellectual property rights in contributions it makes to the Proposal.

9.      COM21 HEADEND DEVELOPMENT AND RESALE BY 3COM

        9.1 Development. Com21 shall use commercially reasonable efforts to
design and develop the first generation Com21 Headend in accordance with a
mutually agreeable schedule. The parties agree to meet to discuss the status and
direction of Com21's design and development of the Com21 Headend and to assess
how 3Com could assist to accelerate and enhance such design and development.

        9.2 Resale by 3Com. The parties agree that 3Com shall be permitted to
resell the Com21 Headend pursuant to the terms and conditions of a reseller
agreement, entitled 'Headend Distribution Agreement', to be agreed upon and
entered into by the parties. Com21 shall escrow the designs for the Com21
Headend for release to enable 3Com to manufacture the Com21 Headend under
certain conditions as more specifically set forth in the Technology Escrow and
Manufacturing License, attached hereto as Exhibit G, (Technology Escrow and
Manufacturing License), to be incorporated into and made a part of the Headend
Distribution Agreement.

        9.3 Com21 Headend Integration within 3Com Platform. The parties agree to
work together to develop by December 31, 1996 a mutually agreeable plan (a) to
make the Com21 Headend compatible for integration within a 3Com platform such as
the Trinity or ONcore architectures (which architecture shall be designated by
3Com) or (b) to provide the necessary technology and specifications for such
integration. The parties agree that they shall perform such plan.

10.0    3COM NIC TECHNOLOGY

        3Com shall develop certain network interface card (NIC) technology and
make products incorporating such technology available to Com21 on mutually
agreeable terms as follows:

        10.1 Low-Cost NICS. 3Com shall provide a low cost network interface card
(NIC) to be independently resold by Com21 and 3Com. This NIC would enable PC
users to connect a cable modem to their PCs. 3Com intends to develop the needed
software to make the installation relatively easy and user friendly.

                                       10
                                   
                                           




        10.2 NIC Drivers. 3Com shall develop NIC PC drivers to enable high
performance and efficient communication between the 3Com Products and the PC.
This could utilize 3Com technology such as the PACE technology.

        10.3 Management Software. 3Com shall develop software to enable remote
configuration and management of PC parameters over the HFC infrastructure such
as AMP and DRMON.

11.     PROPRIETARY RIGHTS

        11.1 Title. Com21 shall be the sole and exclusive owner of the Design
Package, Com21 Technology, Com21 Headend, Com21 Mongoose Product, all
modifications and derivative works (produced by Com21) thereof, the Com21
Trademarks and all proprietary and intellectual property rights therein
throughout the world. Except for the Design Package, Com21 Technology, Com21
Headend and Com21 Mongoose Product, modifications and derivative works (produced
by Com21) thereof and the Com21 Trademarks embodied in the First Generation 3Com
Product, 3Com shall be the sole and exclusive owner of the 3Com Technology and
other technology embodied in the 3Com Products. 3Com agrees to sell to Com21 for
resale as a Com21 branded product any 3Com Product embodying a modification or
derivative work (produced by 3Com) of the Design Package, Com21 Technology or
Com21 Mongoose Product at prices that are not higher than those 3Com charges any
other customer of such product or product containing similar or equivalent
technology at similar volumes. Technology that is made, conceived of or reduced
to practice by the parties jointly in the course of development under this
Agreement shall be jointly owned, without accounting to each other, both parties
having the right to design, develop, make or have made, use, market, sell,
modify, sublicense, lease and support products using the technology arising out
of or obtained with respect to such joint development. To the extent necessary
to bring about the joint ownership of the jointly developed technology, each
party hereby assigns to the other party an undivided ownership interest in their
respective technology in the jointly developed technology. Each party shall use
reasonable efforts to enable the other to use third party technology
incorporated into the Com21 Technology and/or the Com21 Mongoose Product (in the
case of Com21) or the 3Com Technology (in the case of 3Com) under terms and
conditions similar to the terms and conditions such party has received from said
third parties, whether by means of a sublicense or directly from the third
party.

        11.2 Patents. Except as otherwise provided below, 3Com agrees at its
election and own expense (i) to file in the United States Patent and Trademark
Office (the 'PTO') applications ('Applications') for Letters Patents covering
the jointly developed technology, (ii) to diligently prosecute the Applications
and (iii) to maintain in force any patents issuing therefrom. 3Com agrees to
promptly supply Com21 with a complete copy of each Application and all
communications received from, or sent to, the PTO concerning the Applications.
3Com agrees to submit to Com21 for consideration and advice all responses to PTO
communications before filing them, and to give due consideration to Com21's
advice with respect to such responses. The filing and prosecution of foreign
patent applications shall be subject to mutual agreement of the

                                       11






parties. If, 3Com elects not to seek patent protection for any invention of the
jointly developed technology, 3Com shall so notify Com21 in writing and Com21
may, in its sole discretion and at its sole expense, file an Application for
Letters Patent covering such invention and Com21 agrees to diligently prosecute
all such Applications it elects to file. If, at any time, 3Com intends to allow
any Application or any patent lapse, become abandoned or forfeited without
having first filed a substitute, 3Com shall (a) notify Com21 in writing of its
intention at least sixty (60) days before the date on which the application or
patent is due to lapse or become abandoned or forfeited and (b) if requested by
Com21, promptly assign the entire right, title and interest in and to that
application or patent to Com21. Com21 shall be under no obligation to prosecute
or maintain in force any application or patent assigned to it, provided Com21
shall notify 3Com in writing of its intention not to prosecute or maintain any
such application or patent at least sixty (60) days before the date on which the
application or patent is due to lapse or become abandoned or forfeited.

        11.3 Notices. Each party agrees that it will cause to appear on the
container or label for each unit of the products manufactured hereunder
appropriate patent and copyright notices and proprietary data legends as
contained in the Design Package or Com21 Technology delivered by Com21 or First
Generation 3Com Product or 3Com Technology delivered by 3Com, as the case may
be, pursuant to this Agreement or as otherwise reasonably required by the other
party.

12.     WARRANTY

        12.1 Com21 Warrant. Com21 warrants to 3Com that for a period of ninety
(90) days after receipt by 3Com of the Design Package (the 'Warranty Period')
the media on which Com21 delivers the Design Package to 3Com shall be free of
defects in material and workmanship. Com21 shall replace any such defective
media promptly following receipt of written notice from 3Com of such defects
during the Warranty Period. Com21 further represents and warrants to 3Com that
the Com21 Technology and materials contained in the Design Package provided to
3Com will be sufficient to permit 3Com (assuming 3Com has R&D and manufacturing
skill and know-how typical of manufacturers of computer products similar to
cable modem products) to develop the 3Com Product to be compatible with the
Com21 Headend and to conform in all material respects to the Specifications.
EXCEPT FOR THE FOREGOING LIMITED WARRANTIES AND AS SET FORTH IN SECTION 13
(INDEMNIFICATION), COM21 MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS
TO ANY MATTER WHATSOEVER. IN PARTICULAR, ANY AND ALL WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.

        12.2 3Com Warranty to Com21. 3Com warrants to Com21 that for a period of
ninety (90)days after receipt by Com21 of the 3Com Design Package (the '3Com
Warranty Period') the media on which 3Com delivers the 3Com Design Package to
Com21 shall be free from defects in material and workmanship. 3Com shall replace
any such defective media promptly following receipt of written notice from Com21
of such defects during the 3Com Warranty Period. 3Com further represents and
warrants to Com21 that the 3Com Technology and materials contained in

                                       12
                                   
                                           





the 3Com Design Package provided to Com21 will be sufficient to permit Com21
(assuming Com21 has R&D and manufacturing skill and know-how typical of
manufacturers of computer products similar to cable modem products) to develop
the First Generation 3Com Product. EXCEPT FOR THE FOREGOING LIMITED WARRANTIES
AND AS SET FORTH IN SECTION 13 (INDEMNIFICATION), 3COM MAKES NO WARRANTIES,
EXPRESS, IMPLIED OR STATUTORY, TO COM21 AS TO ANY MATTER WHATSOEVER. IN
PARTICULAR, ANY AND ALL WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.

        12.3 Customer Warranty . Each party shall be solely responsible for
customer warranty of any and all products manufactured by such party pursuant to
this Agreement.

13.     INDEMNIFICATION

        13.1 Com21 Indemnification of 3Com. Com21 shall indemnify and hold
harmless 3Com, its officers, directors, employees and agents against any claims,
actions or demands alleging that the Com21 Technology, Com21 Mongoose Product or
Design Package, including all updates thereto (if any) provided to 3Com by
Com21, infringe on any U.S. copyrights, U.S. patents, trade secrets or other
proprietary rights of any third parties.

               (a) This obligation is contingent upon (i) 3Com giving prompt
        written notice to Com21 of any such claim, action or demand, (ii) 3Com
        allowing Com21 to control the defense and related settlement
        negotiations and (iii) 3Com fully assisting, at Com21 expense, in the
        defense.

               (b) Com21 shall have no obligation hereunder for any such claims,
        actions or demands to the extent such claims, actions or demands result
        from:

               (1) The 3Com Product, or portions or components thereof, made in
        accordance with 3Com's specifications; or

               (2) Com21 Technology, Com21 Mongoose Product or Design Package
combined with processes, materials or products not supplied, created, developed
licensed by Com21; or

               (3) The modification or attempted modification of the Com21
Technology, Com21 Mongoose Product or Design Package by parties other than Com21
or the use or distribution of such modified Com21 Technology, Com21 Mongoose
Product or Design Package or

               (4) 3Com's continued alleged infringing activity after being
notified thereof or after being informed of modifications that would have
avoided the infringement.

THE FOREGOING STATES 3COMS SOLE AND EXCLUSIVE REMEDY WITH

                                       13
                                   
                                           





RESPECT TO CLAIMS OF INFRINGEMENT OF PROPRIETARY RIGHTS OF ANY KIND.

        13.2 3Com Indemnification of Com21. 3Com shall indemnify and hold
harmless Com21, its officers, directors, employees and agents against any
claims, actions or demands alleging that the First Generation 3Com Products or
3Com Technology infringe on any U.S. copyrights, U.S. patents, trade secrets or
other proprietary rights of any third parties.

               (a) This obligation is contingent upon (i) Com21 giving prompt
written notice to 3Com of any such claim, action or demand, (ii) Com21 allowing
3Com to control the defense and related settlement negotiations and (iii) Com21
fully assisting, at 3Com expense, in the defense.

               (b) 3Com shall have no obligation hereunder for any such claims,
actions or demands to the extent such claims, actions or demands result from:

                      (1) The Com21 Technology, Com21 Mongoose Product or Design
        Package, unless (i) the 3Com Product, or portion or component thereof,
        is made in whole or in part in accordance with 3Com's specifications or
        (ii) Com21 technology, Com21 Mongoose Product or Design Package is
        combined with materials, processes or products not supplied, created,
        developed or licensed by Com21;

or

                        (2) The modification or attempted modification of the
               First Generation 3Com Product or 3Com Technology by parties other
               than 3Com or the use or distribution of such modified First
               Generation 3Com Product or 3Com Technology
or

                      (3) Com21's continued alleged infringing activity after
               being notified thereof or after being informed of modifications
               that would have avoided the infringement.

THE FOREGOING STATES COM21'S SOLE AND EXCLUSIVE REMEDY WITH RESPECT TO CLAIMS OF
INFRINGEMENT OF PROPRIETARY RIGHTS OF ANY KIND.

14.     CONFIDENTIALITY

        14.1 Confidential Information. Each party acknowledges that in the
course of the performance of this Agreement, it may obtain the Confidential
Information of the other party. The Receiving Party (as defined in Section 1.7
(Confidential Information)) shall, at all times, both during the term of this
Agreement and thereafter for a period of [*], keep in confidence and trust all
of the Disclosing Party's (as defined in Section 1.7 (Confidential Information))
Confidential Information received by it. The Receiving Party shall not use the

                                       14
                                   
                                           

*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.






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 failing 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 effect the intent of 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
agrees to assist the Disclosing Party to remedy such unauthorized use or
disclosure of its Confidential Information.

        14.2 Exceptions to Confidential Information. The obligations set forth
in Section 14.1 (Confidential Information) shall not apply to the extent that
Confidential Information includes information which (a) is already known to the
Receiving Party at the time of disclosure, which knowledge the Receiving Party
shall have the burden of proving; (b) is, or, through no act or failure to act
of the Receiving Party, becomes publicly known; (c) is received by the Receiving
Party from a third party without restriction on disclosure; (d) is independently
developed by the Receiving Party without reference to the Confidential
Information of the Disclosing Party, which independent development the Receiving
Party will have the burden of proving; (e) is approved for release by written
authorization of the Disclosing Party; or (f) is required to be disclosed by a
government agency to further the objectives of this Agreement or by a proper
order of a court of competent jurisdiction; provided, however that the Receiving
Party will use its reasonable efforts to minimize such disclosure and will
consult with and assist the Disclosing Party in obtaining a protective order
prior to such disclosure.

        14.3 Remedies. Each party acknowledges and agrees that any breach of
this Section 14 (Confidentiality) by a party's unauthorized use or disclosure of
the Com21 Technology, the 3Com Technology or the Design Package, as the case may
be, would cause irreparable injury to the other party for which monetary damages
are not an adequate remedy. Accordingly, in addition to other available
remedies, the non-breaching party will be entitled to obtain appropriate
injunctive relief and other equitable remedies in the event of such breach.

15.     LIMITATION OF LIABILITY

        EXCEPT FOR A BREACH OF SECTION 14 (CONFIDENTIALITY), NEITHER PARTY SHALL
HAVE ANY LIABILITY FOR INCIDENTAL, CONSEQUENTIAL, INDIRECT, SPECIAL OR PUNITIVE
DAMAGES OR LIABILITIES OF ANY KIND OR FOR LOSS OF REVENUE, LOSS OF BUSINESS OR
OTHER FINANCIAL LOSS OR FOR ANY COST OF PROCUREMENT OF SUBSTITUTE GOODS,
SERVICES OR TECHNOLOGY ARISING OUT OF OR IN CONNECTION WITH THIS AGREEMENT,
INCLUDING WITHOUT LIMITATION IN CONNECTION WITH THE MANUFACTURE, SALE,
INSTALLATION, USE, PERFORMANCE, FAILURE OR

                                       15
                                   
                                           





INTERRUPTION OF THE PRODUCT(S) LICENSED HEREUNDER, REGARDLESS OF THE FORM OF THE
ACTION, WHETHER IN CONTRACT, TORT (INCLUDING NEGLIGENCE) STRICT PRODUCT
LIABILITY OR OTHERWISE, EVEN IF ANY REPRESENTATIVE OF A PARTY HERETO HAS BEEN
ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

16.     EXPORT CONTROLS

        Each party agrees that it will not knowingly, without prior
authorization, if required, of the Office of Export Administration, U.S.
Department of Commerce 14th and Constitution Ave., N.W., Washington, D.C. 20230,
export or reexport (as defined in Section 779.1(b)-(c) of the Export
Administration Regulations - 'Regulations' - and any amendments thereto) the
technical data relating to the Com21 Mongoose Product, Com21 Headend, 3Com
Product, Com21 Technology or 3Com Technology or the direct products of such
technical data to Afghanistan, the People's Republic of China or to any Group Q,
S, W, Y or Z country specified in Supplement No. 1 to Section 770 of the
Regulations as amended from time to time.

17.     TERM AND TERMINATION

        17.1 Term. This Agreement shall be effective from the Effective Date for
a period of five (5) years, unless earlier terminated in accordance with its
terms. Thereafter, this Agreement shall automatically be renewed on its
anniversary dates for successive one (1) year terms subject to a party providing
written notice to the other party no later than sixty (60) days prior to any
such anniversary date of such party's intent not to renew in which event this
Agreement shall terminate at the end of the then current term; provided that, in
the event of Com21's failure to renew, the Licenses granted to 3Com under
Section 2 (Licenses) above shall continue in full force in perpetuity.

        17.2 Termination Due to Bankruptcy, etc. In the event a party (i)
becomes insolvent; (ii) voluntarily files a petition under applicable bankruptcy
or insolvency laws which such party fails to have released within thirty (30)
days after filing, (iii) has filed against it a petition under applicable
bankruptcy or insolvency laws which such party fails to have released within
ninety (90) days (thirty (30) days if such party fails to contest the petition
in good faith) after filing; (iv) proposes any dissolution, composition or
financial reorganization with creditors or if a receiver, trustee, custodian or
similar agent is appointed or takes possession with respect to all or
substantially all property or business of such party; or (v) such party makes a
general assignment for the benefit of creditors, the other party may terminate
this Agreement by giving a termination notice, which termination shall become
effective ten (10) days after mailing.

        17.3 Right to Terminate. Either party shall have the right to terminate
this Agreement if the other party is in material breach of any term or condition
of this Agreement and fails to remedy such breach within thirty (30) days
(twenty (20) days in the case of a

                                       16
                                   
                                           





breach of a payment obligation) after receipt of written notice of such breach
given by the non-breaching party; provided, however, that a breach of the
obligations set forth in Section 14 (Confidentiality) shall be grounds for
immediate termination by the non-breaching party of this Agreement.

        17.4 Obligations Upon Termination caused by 3Com Breach. Upon the
termination of this Agreement caused by 3Com's material breach of this
Agreement:

               (a) 3Com's obligations to pay all sums due hereunder shall be
accelerated and all such sums shall be due and payable on the date of
termination or expiration;

               (b) The licenses granted to 3Com hereunder shall terminate and
3Com shall discontinue the use, manufacture, reproduction, distribution and
sublicensing (as applicable of the Com21 Technology, Com21 Mongoose Product and
Design Package licensed from Com21;

               (c) 3Com may keep one (1) copy of the Com21 Technology, Com21
Mongoose Product and Design Package to be used solely for support of its
installed base of 3Com Products and 3Com shall have a limited license to the
extent necessary for 3Com to support the installed base of 3Com Products.

        17.5 Obligations Upon Termination caused by Com21 Breach. Upon the
termination of this Agreement caused by Com21's material breach of this
Agreement:

               (a) Com21's obligations to pay all sums due hereunder shall be
accelerated and all such sums shall be due and payable on the date of
termination or expiration;

               (b) The licenses granted to Com21 hereunder shall terminate and
Com21 shall discontinue the use, manufacture, reproduction, distribution and
sublicensing (as applicable) of the 3Com Technology and First Generation 3Com
Product licensed from 3Com;

               (c) Com21 may keep one (1) copy of the 3Com Technology and First
Generation 3Com Product to be used solely for support of its installed base of
First Generation 3Com Products and Com21 shall have a limited license to the
extent necessary for Com21 to support the installed base of First Generation
3Com Products.

        17.6 Other Obligations Upon Termination. Except as otherwise provided in
Sections 17.4(c) and 17.5(c) above, upon the expiration or earlier termination
of the Agreement, the Receiving Party shall, within fifteen (15) days of any
termination or expiration of this Agreement, return to the Disclosing Party or
destroy all full or partial copies, in whatever media, of any and all materials
in the Receiving Party's possession which had been furnished to the Receiving
Party by the Disclosing Party pursuant to this Agreement, and the Receiving
Party shall warrant in writing to the Disclosing Party within thirty (30) days
after termination or expiration that all such materials have been returned to
the Disclosing Party or destroyed.

                                       17
                                   
                                           






        17.7 Survival. Neither the termination or expiration of this Agreement
shall relieve either party from its obligations to pay the other any sums
accrued hereunder. The parties agree that their respective rights, obligations
and duties under Sections 2 (Licenses) (except as otherwise set forth in this
Section 17 (Term and Termination)), II (Proprietary Rights), 13
(Indemnification), 14 (Confidentiality), 15 (Limitation of Liability), and 17
(Term and Termination), 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 and remain in effect for a period of five
(5) years thereafter or the period specified in this Agreement, if longer.

18.     MISCELLANEOUS

        18.1 Notices. Any notice provided for or permitted under this Agreement
will be treated as having been given when (a) delivered personally, (b) sent by
confirmed telex or telecopy, (c) sent by commercial overnight courier with
written verification of receipt, or (d) mailed postage prepaid by certified or
registered mail, return receipt requested, to the party to be notified, at the
address set forth below, or at such other place of which the other party has
been notified in accordance with the provisions of this Section 18.1 (Notices).

               If to 3Com:   3Com Corporation
                             5400 Bayfront Plaza
                             Santa Clara, CA 95052
                             Telecopy:  (408) 764-8955
                             Attention: PCOps Purchasing Manager

        with a copy to the attention of 3Com's General Counsel at the address
        above, and a telecopy number of (408) 764-6434.

               If to Com21:  Com21, Inc.
                             1991 Landings Drive
                             Mountain View, CA 94043
                             Telecopy:  (415) 254-5883
                             Attention: President

                and copy to: Brobeck, Phleger & Harrison LLP
                             Two Embarcadero Place
                             2200 Geng Road
                             Palo Alto, CA 94303
                             Telecopy:  (415) 496-2885
                             Attention: Edward M. Leonard, Esq.

Such notice will be treated as having been received upon the earlier of actual
receipt or five (5) days after posting.


                                       18
                                   
                                           





        18.2 Amendment: Waiver. This Agreement may be amended or supplemented
only by a writing that is signed by duly authorized representatives of both
parties. No term or provision hereof will be considered waived by either party,
and no breach excused by either party, unless such waiver or consent is in
writing signed on behalf of the party against whom the waiver is asserted. No
consent by either party to, or waiver of, a breach by either party, whether
express or implied, will constitute a consent to, waiver of, or excuse of any
other, different, or subsequent breach by either party.

        18.3 Severability. If any provision of this Agreement is held invalid or
unenforceable for any reason, the remainder of the provision shall be amended to
achieve as closely as possible the economic effect of the original term and all
other provision shall continue in full force and effect.

        18.4 Governing Law. This Agreement shall be governed by and construed
under the laws of the United States and the State of California as applied to
agreements entered into and to be performed entirely within California between
California residents. The parties agree that the United Nations Convention on
Contracts for the International Sale of Goods is specifically excluded from
application to this Agreement.

        18.5 Choice of Forum. The parties hereby submit to the jurisdiction of,
and waive any venue objections against, the United States District Court for the
Northern District of California, San Jose Branch and the Superior and Municipal
Courts of the State of California, Santa Clara County, in any litigation arising
out of the Agreement.

        18.6 Injunctive Relief. It is expressly agreed that a material breach of
this Agreement (except Section 14 (Confidentiality)) by a party could 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 in the event of any threatened or actual
violation of any or all of the provisions hereof.

        18.7 Attorneys' Fees. In any action to enforce this Agreement, the
prevailing party shall be awarded all court costs and reasonable attorneys' fees
incurred, including such costs and attorneys' fees incurred in enforcing and
collecting any judgment.

        18.8 Force Majeure. Except for the payment of money, neither party will
be liable for any failure or delay in performance beyond its control under this
Agreement due to fire, explosion, earthquake, storm, flood or other weather,
unavailability of necessary utilities or raw materials, war, insurrection, riot,
act of God or the public enemy, law, act, order, export control regulation,
proclamation, decree, regulation, ordinance, or instructions of Government or
other public authorities, strikes, lockouts or other labor disputes or shortages
or inability to obtain material or equipment, compliance with laws or regulation
(including, without limitation, those related to infringement) or judgment or
decree of a court of competent jurisdiction (not arising out of breach by such
party of this Agreement). In the event of the happening of such a cause,

                                       19
                                   
                                           





the party whose performance is so affected will give prompt, written notice to
the other party, stating the period of time the same is expected to continue and
will use its best efforts to mitigate the effect of the event giving rise to the
failure or delay in performance.

        18.9 Assignment. 3Com may assign this Agreement to any person to whom it
transfers all or substantially all of its proprietary rights in the 3Com Product
and 3Com Technology. Otherwise, neither party may assign, voluntarily, by
operation of law, or otherwise, any rights or delegate any duties under this
Agreement (other than the right to receive payments) without the other party
prior written consent and any attempt to do so without such consent will be void
except that an assignment to an acquiror of all or substantially all of a
party's stock, assets or business shall not require prior written consent of the
other party. This Agreement will bind and inure to the benefit of the parties
and their respective successors and permitted assigns.

        18.10 Relationship of the Parties. The parties to this Agreement are
independent contractors. There is no relationship of agency, partnership, joint
venture, employment, or franchise between the parties. Neither party has the
authority to bind the other or to incur any obligation on its behalf.

        18.11 Allocation of Risk. The sections on limitation of liability,
warranties and disclaimer of warranties allocate the risks in the Agreement
between the parties. This allocation is an essential element of the basis of the
bargain between the parties.

        18.12 Publicity. Neither party shall disclose the terms of this
Agreement without the prior approval of the other party, except that a party may
disclose the terms of this Agreement where required by law, provided that such
party makes every reasonable effort to obtain confidential treatment or similar
protection to the fullest extent available to avoid public disclosure of the
terms of this Agreement. A party required by law to make disclosure of the terms
of this Agreement will promptly notify the other party and permit the other
party to review and participate in the application process seeking confidential
treatment.

        18.13 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. The titles and headings herein are
for reference purposes only and shall not in any manner limit the construction
of this Agreement, which shall be considered as a whole.

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

        18.15 Entire Agreement. This Agreement, including all Exhibits to this
Agreement, constitutes the entire agreement between the parties relating to this
subject matter and supersedes all prior or simultaneous representations,
discussions, negotiations, and agreements, whether

                                       20






written or oral.

        IN WITNESS WHEREOF, the parties hereto have executed this Agreement on
the dates set forth below effective as of the Effective Date.

    3COM CORPORATION                       COM21, INC.

    By:                                      By:
       -------------------------------          -------------------------------

    Name:                                    Name:
         -----------------------------            -----------------------------

    Title:                                   Title:
          ----------------------------             ----------------------------

    Date: March 22, 1996                     Date: March 22, 1996
         -----------------------------            -----------------------------

List of Exhibits:

A - Com21 Technology
B - Specifications
C - Com21 Mongoose Product Specification
D - Com21 Mongoose Product Acceptance Criteria
E - Design Package
F - Com21 Trademarks
G - Technology Escrow and Manufacturing License



                                       21
                                   
                                           





                                    EXHIBIT A

                                 COM21TECHNOLOGY
           [to be prepared and delivered consistent with Section 5.2]




Cable modem CATV MAC and PHY interface specifications

Cable modem management message protocol

Cable modem system design

Cable modem circuit design

Cable modem printed circuit board design

Cable modem diagnostic firmware

Cable modem operational firmware

Cable modem ASIC source code (RTL)

Cable modem specifications and test criteria

Cable modem mechanical design







                                       22
                                   
                                           





                                    EXHIBIT B

                                 SPECIFICATIONS
                    [to be attached at the time of execution]










                                       23
                                   
                                           





                                    EXHIBIT C

                      COM21 MONGOOSE PRODUCT SPECIFICATION
         [Product Specification to be attached at the time of execution]










                                       24
                                   
                                           





                                    EXHIBIT D

                   COM21 MONGOOSE PRODUCT ACCEPTANCE CRITERIA

                       [Acceptance criteria to be prepared
                  and attached within 60 days after execution]


                   COM21 Mongoose Product Acceptance Criteria
                               Contract Exhibit D

Revision 1.0, 6/07/96
Ed Boyd
John Griesing

The following will be used to determine the acceptance of the Mongoose product.
All of the items listed in the document will be required to accept the Mongoose
product at meeting the Acceptance Criteria.


1.      Design Package

        The following is the design package that 3Com expects to receive
        relative to the Mongoose product. It is expected that this package will
        be available in it's entirety at the time of fabrication of the final
        Mongoose product.

-       RTL Verilog Code that compiles without errors and with all warnings
        messages investigated.

-       Verilog simulation environment with self checking test cases. A self
        checking test case will report an error when the feature to be tested
        fails.

-       Behavioral, minimum delay netlist, typical delay netlist, and maximum
        delay netlist simulations passing in Verilog simulation environment.

-       Set of test vectors with 90% or greater test coverage.

-       Simulate vectors using minimum, typical, and maximum delays.

-       Simulate vectors using dynamic timing analyzer (i.e. Epilog) (optional).

-       Synopsys scripts for synthesis and complete set of timing constraints
        for synopsys.

-       Synopsys static timing analysis completed without violations.


2.      Environmental Conditions

        The following conditions will be tested on the device.

-       Temperature testing over operating range (0C-70C)

-       Voltage margining (4.75 - 5.25 V)

-       Timing Verification (per specification)


                                       25
                                   
                                           





-       29K Bus

-       Modulator/Demodulator

-       SRAM

-       MACE

-       Mongoose BER (Bit Error Rate) Less than IOE-9

3.      Mongoose Scenarios to be verified with final silicon.

-       Ethernet Packet Bridging.

        -       Send packets to learn source addresses. Verify bridging based on
                learned addresses. Verify aging of old addresses and replacement
                of oldest entries.

        -       Send broadcast packets. Verify bridging based on ethertype table
                and broadcast rate count.

        -       Send packets directed to processor. Verify bridging based on
                local MAC enable switch, MAC address table, and multicast
                address table.

        -       Send multicast packets. Verify bridging based on multicast
                address table.

-       MACE Interface.

        -       Transmit packets with MACE underruns, max collisions, and late
                collisions. Verify detection and recovery.

        -       Receive packets that had late collisions, CRC errors, alignment
                errors, and overruns. Verify detection and recovery. 

-       Determine cell and frame boundaries.

        -       Verify Cell delination detection.

        -       Verify Frame delination detection.

        -       Generate T7EI errors. Verify detection and recovery.

        -       Corrupt/change both frame and cell boundaries. Verify detection
                of loss, reestablishment or connection, and graceful termination
                to upstream transmission.

-       Decryption of packet.

        -       Decrypt OAM, AAL5 and raw ATM cells using all 10 keys based on
                the VPI. Verify cell contents.

-       Downstream packet routing.

        -       Send OAM's packet and verify reception into queue 0.

        -       Send good and bad CRC-10 in OAM packets. Verify mongoose
                detection.

        -       Send Raw ATM cells to queues I and 2. Verify cell contents.

        -       Send AAL5 cells to queues 3, 4, & 5. Verify cells contents.

        -       Send good and bad CRC-32's with AAL5 packets. Verify mongoose
                detection.

-       Downstream grant queuing.

        -       Send Acquisition grants. Verify detection, queuing, and random
                backoff.

        -       Send Contention grants. Verify detection, queuing and random
                backoff. Verify transition for Acquisition to Active state.

        -       Verify transition from Active to Idle state.

        -       Send Directed grants. Verify state changes and proper queuing.

        -       Overflow grant queue. Verify recovery.

                                       26
                                   
                                           





        -       Send grants with bad CRC-10's. Verify removal from queue.

-       Encryption of packet.

        -       Encrypt OAM, AAL5 and raw ATM cells using all 4 keys. Verify
                cell contents.

        -       Encrypt packet with decryption occurring on downstream channel.

-       FEC Generation.

        -       Verify FEC on upstream data. Generate bit errors and verify
                reception at head end.

-       Upstream Queues.

        -       Upload multiple packets into all queues. Verify priority
                ordering and packet boundaries.

-       Upstream Cell Generation.

        -       Send AAL5 Packets upstream. Verify header information, HEC,
                CRC-32, and reassembled packet at head end.

        -       Send OAM packets. Verify header information, HEC, CRC-10, and
                payload data.

        -       Send raw ATM cells. Verify data.

-       Upstream traffic.

        -       Verify IDLE cell Generation.

        -       Verify start of frame delay.

-       Ability to gracefully reset queues, MACE, and cable modem interface.

-       Generate and acknowledge all interrupts.

-       Read and write all processor accessible registers.

4.      Test Equipment

The above testing requires the following equipment from Com21

-       Latest version HCX and associated SW








                                       27
                                   
                                           





                                    EXHIBIT E

                                 DESIGN PACKAGE

     [description of materials to be delivered consistent with Section 5.2]










                                       28
                                   
                                           





                                    EXHIBIT F

                                COM21 TRADEMARKS

                               [to be determined]










                                       29
                                   
                                           





                                    EXHIBIT G

                   TECHNOLOGY ESCROW AND MANUFACTURING LICENSE

Definitions

        'Products' means the Com21 Headend products to be sold by Com21 to 3Com
under the Headend Distribution Agreement, and shall include all enhancements,
fixes, Updates, Upgrades and modifications to the Products made by or for Com21.
'Update' shall mean a replacement of all or a portion of a Product that is
primarily intended to Fix an error or deficiency in the Product. 'Upgrade' shall
mean a replacement of all or a portion of a Product that is primarily intended
to add functionality or performance to the Product and for which a separate or
additional charge is made to the end user.

'Technology Documentation' means all designs, drawings, specifications, test
information, vendor lists, source and object code versions of the software
incorporated into or used by Com21 to design, manufacture or maintain the
Products and all other data and information owned by Com21 or to which Com21 has
the right to grant sublicenses with respect to the design, manufacture and use
of the Products. The Technology Documentation will include a list of third party
technology, if any, in the Products to which Com21 cannot sublicense the rights
envisioned by the manufacturing license below, and persons at such third parties
to contact regarding obtaining licenses. The Technology Documentation will
further include a list of consultants, if any, whom Com21 reasonably believes
could provide technical support to 3Com in connection with 3Com's exercising of
the rights under the manufacturing license below. Prior to the date of first
shipment of the Product by Com21 to 3Com, the parties will attach an exhibit to
the Headend Distribution Agreement that sets forth a complete list of the
Technology Documentation that exists as of such date. Com21 shall update such
Technology Documentation if it updates its own archival copy of the Technology
Documentation.

Technology Escrow and Manufacturing License

        Within ten (10) days after the first shipment of Products from Com21 to
3Com, Com21 shall place the Technology Documentation for all versions of the
Products initially agreed to be sold by Com21 to 3Com under the Headend
Distribution Agreement in a mutually agreed upon escrow account pursuant to the
form of escrow agreement previously provided by 3Com to Com21. Thereafter,
within ten (10) days after the execution of any amendments to the Headend
Distribution Agreement to add additional updates or versions of the Products or
to add new Products, Com21 shall place the Technology Documentation for such
Products into such escrow account. 3Com shall pay any and all annual fees,
deposit fees, reporting fees and costs associated with such escrow, however,
Com21 will bear its own cost of creating the deposit and all updates thereto.
Com21 hereby grants to 3Com a worldwide, nonexclusive, fully-paid, royalty-free,
perpetual, irrevocable license to manufacture, have manufactured, sell, repair,
use, develop, modify, reproduce, and distribute the Products under all
registered and unregistered copyrights, patents, trade secrets, mask works,
designs,

                                       G-1
                                   
                                           




drawings, specifications, vendor lists and all other data and other information
owned by Com21 or to which Com21 has the right to grant sublicenses with respect
to the design, manufacture, maintenance and use of the Products and any other
intellectual property rights associated therewith, and to prepare and have
prepared derivative works based thereon, and to use source code for the software
contained in or associated with the Products to make and have made, use,
develop, modify, reproduce, distribute and sell the Products and prepare and
have prepared derivative works based on the Products, and to grant sublicenses
to third parties as to any or all of the rights granted to 3Com under this
license, only in the event Com21 becomes insolvent, generally fails to pay or
admits in writing its inability to pay its debts as they become due, (ii)
applies for or consents to the appointment of a trustee, receiver or other
custodian or makes a general assignment for the benefit of its creditors, (iii)
any bankruptcy, reorganization, debt arrangement or other case or proceeding
under any bankruptcy or insolvency law or other dissolutions or liquidation
proceedings are commenced by or against Com21 and, if such case is not commenced
by Com21, it is acquiesced in or remains undismissed for ninety (90) days, (iv)
Com21 takes any corporate or other action to authorize, or in furtherance of,
any of the foregoing, (v) any event occurs which would permit 3Com to terminate
the Headend Distribution Agreement or the Technology License and Reseller
Agreement to which this exhibit is attached as Exhibit G (Technology Escrow and
Manufacturing License) (except as described in Section 5.3 (Acceptance) or if
3Com elects not to renew in accordance with Section 17.1 (Term) of the
Technology License and Reseller Agreement), (vi) Com21 ceases, or gives notice
that it intends to cease, manufacturing and distributing the Products or (vii)
Com21 is unable to meet the reasonable supply requirements of 3Com's customers.
The occurrence of any of the foregoing shall constitute an 'Event of Escrow
Release' for purposes of the Headend Distribution Agreement.


                                       G-2