EXHIBIT 10.12


                      HOME PHONELINE PROMOTER'S AGREEMENT
                      ----------------------------------- 


     This Agreement is effective as of June 1, 1998 by and between IBM
Corporation ("IBM"), Hewlett-Packard Company ("HP"), Compaq Computer Corporation
("Compaq"), Advanced Micro Devices, Inc. ("AMD"), Intel Corporation ("Intel"),
Tut Systems, Inc. ("Tut"), Epigram, Inc. ("Epigram"), AT&T Wireless Services
Inc. ("ATTWS"), 3Com Corporation ("3Com"), Rockwell Semiconductor Systems, Inc.
("Rockwell"), and Lucent Technologies Inc. ("Lucent") and the Affiliates of
these Corporations, collectively referred to as the "Promoters".

                                   BACKGROUND

     A.   The Promoters intend to define, establish and support a home
networking system specification which provides the basic networking capability
but is also compatible with other uses of the home telephone lines.  This
specification is referred to as Home Phoneline.

     B.   The Promoters also intend to develop a verification testing portion of
the specification to verify compliance with the Home Phoneline specification.

     C.   The Promoters wish to encourage broad and open industry adoption of
Home Phoneline and wish to facilitate the provision of necessary licenses to do
so.  The Promoters intend to provide the Home Phoneline specification to an
appropriate standards body.

     D.   The Promoters also desire to provide for the possibility of issuing
revisions and updates to the Home Phoneline specification.

                                   AGREEMENT

1.   DEFINITIONS.

     1.1  "Adopter" means any entity that has executed an identical copy of
Attachment A ("Adopter's Agreement") and has delivered it to the Promoters as
provided in Section 2.2 below and its Affiliates.

     1.2  "Affiliate" is an entity that directly or indirectly controls, is
controlled by, or is under common control with another entity, so long as such
control exists.  This definition of Affiliate is modified for ATTWS to mean only
directly or indirectly controls another entity, as long as such control exists.
ATTWS agrees to make commercially reasonable efforts to obtain the necessary
approvals to allow ATTWS to utilize the unmodified Affiliates definition.
"Control" means beneficial ownership of more than fifty percent of the voting
stock or equity in an entity.

     1.3  "Fellow Adopters" are the Promoters and all Adopters.

 
                      HOME PHONELINE PROMOTER'S AGREEMENT
                      -----------------------------------


     1.4  "Participant" means an entity that has executed a copy of the
Participant Agreement in the form attached hereto as Attachment B
("Participant's Agreement"), delivered it to any Promoter, had the Promoter
execute it and then had the fully executed agreement received by the Secretary.
No changes to the Participant's Agreement shall be made without the unanimous
approval of the Promoters, except for the change specified in paragraph 2.3(a)
below.  The Secretary shall keep a master Participants list that shall be made
available to the other Promoters at any time upon request.

     1.5  "Necessary Claims" shall mean those claims of all patents, other than
design patents and design registrations, throughout the world entitled to an
effective filing date prior to January 1, 2003, which a Promoter or Adopter, as
applicable, or its Affiliates has the right, at any time during the term of this
Agreement, to grant licenses of the scope granted herein without such grant or
the exercise of rights thereunder resulting in payment of royalties or other
consideration to third parties (except for payments to Affiliates or to
employees within the scope of their employment) and (i) which are necessarily
infringed by an implementation of a version of the Specification adopted by the
Promoters pursuant to Section 4.3 below, where such infringement could not have
been avoided by another commercially reasonable noninfringing implementation of
such Specification, or (ii) for which infringement is based on an implementation
of any example included in the body of the Specification.  Necessary Claims
shall not include, and no license shall apply to, implementation examples
included solely in any appendix, exhibit or other attachment to the actual
Specification.

     1.6  "Specification" means the document entitled Home Phoneline as finally
adopted by the Promoters pursuant to Section 4.3 below, authored and published
by the Promoters; any updates as finally adopted pursuant to Section 4.4; and
non-final versions until a first final version is adopted. The scope of the
Specification shall be restricted to that information descriptive (i) of the
electrical characteristics and protocols of physical interfaces, (ii) of a
standard set of transmitted signals and (iii) of such test procedures as
required to establish conformance of devices to items (i) and (ii).

     1.7  "Fully Compliant" means: (a) an implementation of the Specification
which supports or implements all of the portions of the Specification defined by
the Specification as being "Required" or (b) an implementation of all portions
of the Specification required for a specific type of product or component
thereof.

2.   COVENANTS.

     2.1  Grants of Licenses to Promoters and Adopters.  Upon agreement by the
          --------------------------------------------                        
Promoters as to the final version of the text of the Specification as set out in
Section 4.3, each Promoter (on behalf of itself and its Affiliates) hereby
covenants to grant to each of the other Promoters and to all Adopters under
reasonable terms and conditions that are demonstrably free of any unfair
discrimination, a nonexclusive, nontransferable, non-sublicenseable (except as
part of the transfer of an end user product), worldwide license under its
Necessary Claims to implement the Specification 

                                      -2-

 
                      HOME PHONELINE PROMOTER'S AGREEMENT
                      ----------------------------------- 

and to make, have made, use, import, offer to sell, lease, sell, promote and
otherwise distribute the resulting implementation (whether implemented in
hardware, software, or some combination of hardware and software); provided,
however, (i) the resulting implementation is Fully Compliant, (ii) such license
shall not extend to features of a product which are not required to comply with
the Specification or to other specifications and APIs (Application Programming
Interfaces), such as a Promoter's operating system API, and (iii) such license
shall be granted only to the extent that the resulting implementation is used
for the purposes of home or LAN networking over home or any single pair in-
premises telephone lines. To the extent a Promoter becomes aware of any
Necessary Claims which are or will be subject to the above license and to the
extent that a Promoter intends to seek a reasonable royalty for such Necessary
Claims pursuant to the above license, such Promoter shall promptly notify the
other Promoters (and the Adopters in a manner agreed to by the Promoters) of
such Necessary Claims. If such notification is not provided prior to adoption of
the version of the Specification where such Necessary Claims develop, the
Promoter shall not request an injunction for such Necessary Claims in connection
with the Specification as used by the Promoters and Adopters. Additionally, to
the extent a Promoter becomes aware of claims which would be Necessary Claims
but for the obligation to pay royalties or other consideration to third parties,
the Promoter shall promptly notify the other Promoters (and the Adopters in a
manner agreed to by the Promoters) of such claims.

     2.2  Licenses to Adopters.  Any Promoter may provide the Adopter's
          --------------------                                         
Agreement (Attachment A hereto) to any third party who wishes to be an Adopter.
Upon the execution of the Adopter's Agreement by such Promoter and such third
party, and receipt by the Secretary (as defined in Section 2.3 below) of a
properly executed copy of such Agreement, such Agreement shall be effective.  No
changes to the Adopter's Agreement shall be made without the unanimous approval
of the Promoters, except for the change specified in paragraph 2.3(a) below.
The Secretary shall keep a master Adopters list that shall be made available to
the other Promoters at any time upon request.

     2.3  Administration of the Specification.
          ----------------------------------- 

          (a) A Promoter shall be appointed as the secretary for the
Specification (the "Secretary").  The Secretary shall be responsible for keeping
a list of all Adopters and Participants and keeping copies of all Adopter's
Agreements and Participant's Agreements.  Compaq agrees to act as the Secretary
for the Home Phoneline Specification.  Should the acting Secretary desire to
cease acting as the Secretary, or should it withdraw as a Promoter from the
Specification or any proposed update thereto, the Promoters shall appoint
another Promoter as the new Secretary, and (i) the outgoing secretary shall
provide the new Secretary with its files of Adopters, Participants and their
agreements with the Promoters, and (ii) the Adopter's Agreement and
Participant's Agreements shall be amended so that newly executed Agreements
shall become effective upon receipt of the new Secretary.

                                      -3-

 
                      HOME PHONELINE PROMOTER'S AGREEMENT
                      ----------------------------------- 

          (b) Each of the Promoters shall promptly notify each other of any
violation, that may come to such Promoter's attention, of any Adopter's
Agreement by an Adopter or Participant's Agreement by an Adopter or Participant.
Each Promoter shall have the right to enforce compliance with the terms of such
Agreements by Adopters and Participants upon notice to the other Promoters. Any
Promoter may, at its option, bring suit against such Adopter or Participant to
enforce such Agreement.  The other Promoters shall, at their discretion, provide
reasonable assistance in the prosecution of such suit, at the expense of the
prosecuting party (except for the value of time of the assisting party's
employees); provided, however, that no Promoter shall be required to be named as
a party to such suit.  In the event a Promoter does not wish to participate in
the enforcement action and is nonetheless joined as a necessary party or the
like, the Promoter(s) initiating the enforcement action agree(s) to pay the
reasonable expenses incurred by the joined Promoter in such enforcement action
(except for the value of time of the assisting party's employees).  The
prosecuting party will retain any recovery in such suit.

     2.4  Copyright Notices.  Any publication of the Specification shall contain
          -----------------                                                     
an appropriate copyright notice in the names of all the Promoters.  Public
references to the Specification shall attribute authorship to the Promoters to
the extent practical.

     2.5  References to Specification.  The Promoters hereby agree not to assert
          ---------------------------                                           
against any Promoter or any Adopter any trademark or trade name rights they may
have now or hereafter in any name or logo unanimously adopted by the Promoters
for use in connection therewith or with this Agreement.  If the Promoters agree
to claim or assert trademark or trade name rights in such name or logo, they
agree to use commercially reasonable efforts, that represent the best interests
of all parties, to agree on the nature of ownership, licensing, guidelines for
usage, and registration of such name or logo.  Prior to adoption of a new name
or logo, the Promoters shall transmit a proposed name or logo to the
Participants and Adopters for comments regarding any claimed rights in such new
name or logo.  The Promoters will not use any name or logo unanimously adopted
by the Promoters except to refer to the Specification and to products which
fully comply with the Specification.

3.   COPYRIGHT OWNERSHIP/MODIFICATIONS TO SPECIFICATION.

     3.1  Title.  Each Promoter shall own, and is hereby conveyed, a non-
          -----                                                         
exclusive, undivided, and equal ownership in the copyrights in the
Specification.  Each Promoter may exercise any and all rights of copyright
ownership and sublicense such rights in the Specification as if such rights were
solely owned by such Promoter and without permission of the other Promoters and
without any duty to account.  Any Promoter may propose an enforcement action,
and the other Promoters shall have the right to participate at their own expense
and at their own discretion.  On request of any Promoter considering suit
against a third party, the other Promoters shall, at their discretion, provide
reasonable assistance in the prosecution of such suit, at the expense of the
prosecuting party (except for the value of time of the assisting party's
employees); provided, however, that no Promoter shall be required to be named as
a party to such suit.  In the event a Promoter does not wish to participate 

                                      -4-

 
                      HOME PHONELINE PROMOTER'S AGREEMENT
                      ----------------------------------- 

in the enforcement action and is nonetheless joined as a necessary party or the
like, the Promoter(s) initiating the enforcement action agree(s) to pay the
reasonable expenses incurred by the joined Promoter in such enforcement action
(except for the value of time of the assisting party's employees). The
prosecuting party will retain any recovery in such suit. If a Promoter wishes to
register the Specification with the Copyright Office, it may do so at its own
expense, and the other Promoters shall cooperate with such Promoter to the
extent reasonably required to file the application for copyright registration.
No further obligation will exist after the application is filed.

     3.2  Modifications.  Any modifications to or derivative works of the
          -------------                                                  
Specification shall be owned solely by the Promoter(s) creating them, subject to
the underlying copyright in the Specification, unless and until such
modification is adopted as an update.  However, except for excerpts or
quotations from a published Specification, no Promoter shall publish such a
modified or derivative work or translation into a foreign language without the
express written consent of the other Promoters.  This restriction on modified or
derivative works shall not apply to any Promoter once the Promoter withdraws.
The parties will cooperate from time to time with respect to responsibility for
translation of the Specifications into foreign languages, and shall equally
share the out-of-pocket costs therefor.

4.   SPECIFICATION COMPLETION.

     4.1  Specification Release to Participants and Adopters.  The Promoters
          --------------------------------------------------                
shall cooperate to finalize the Specification according to the following
procedure:

          (a) Any proposal for the Specification shall be authorized for release
to third parties (including Adopters and Participants) only by 2/3 majority
agreement of the Promoters.

          (b) The Promoters shall use reasonable efforts to expedite
edits/changes suggested to each revision of the Specification as quickly as
possible.

     4.2  Specification Development.  Non-final revisions of the Specification
          -------------------------                                           
may be designated unreleased or released and shall be maintained in confidence
and only disclosed pursuant to the terms herein.  Unreleased revisions shall
only be shared among the Promoters.  Agreement of a 2/3 majority of the
Promoters is required to designate an unreleased revision as a released
revision. Once a revision of the Specification has been authorized for release,
a Promoter may provide a copy of such revision to a Participant and solicit
suggestions for incorporation in the Specification from the Participant.

     4.3  Published Specification.  The Specification or any proposed update
          -----------------------                                           
thereof shall be deemed final and is adopted when the Promoters agree by a 2/3
majority, in writing, that such version of the Specification is final.  For
purposes of voting on the Specification or for any other voting under this
Agreement, the Affiliates shall not be entitled to vote and their approval is
not 

                                      -5-

 
                      HOME PHONELINE PROMOTER'S AGREEMENT
                      ----------------------------------- 

required in connection with any Vote. Such final Specification shall become
effective and be made publicly available after the thirty (30) day period
specified in Section 4.3(a).

          (a) Any Promoter that votes against the Specification may choose to
withdraw from this Agreement under Section 6 by written notice to all other
Promoters sent within thirty (30) days after the date on which the Secretary
receives the 2/3 majority necessary for adoption of the Specification.
Following such withdrawal, the Promoter will have only those rights and
obligations hereunder set forth under Section 6.2.  A Promoter shall be
considered to have adopted the Adopted Specifications, with all rights and
obligations with respect thereto under this Agreement, if such Promoter (i)
voted in favor of the proposed final Specifications or (ii) failed to vote or
voted against such proposed final Specifications and did not so withdraw.

     4.4    Updates to the Specification.  Once Promoters have agreed upon a
            ----------------------------                                    
final Specification under Section 4.3 above, any updates or alterations to the
finalized Specification shall be treated as a proposal to develop a new
Specification, and shall be subject to the same processes and procedures used
for development of the original specification as outlined above.  Each Promoter
may, in its sole discretion, cooperate with development of such new
Specification or withdraw with regard to such new Specification without
withdrawing from an earlier adopted Specification.   Adoption of such a new
Specification shall not terminate any right or obligation of any Promoter under
this Agreement, including the licenses granted, received or agreed to be made
available with respect to the earlier adopted Specification.

5.   CONFIDENTIALITY.

     5.1  Confidential Information.  Each Promoter will maintain the
          ------------------------                                  
confidential information of the other Promoters, the non-final versions of the
Specification and the contributions each other Promoter and each Participant
makes to the specification in confidence with at least the same degree of care
that it uses to protect its own confidential and proprietary information, but no
less than a reasonable degree of care under the circumstances and will neither
disclose nor copy the non-final versions of the Specification except as
necessary for its employees and contractors (under obligation of
confidentiality) with a need to know for the purpose of developing or updating
the Specification or implementing a product according to the Specification.  Any
information incorporated in a particular revision of the Specification,
including any exhibits or attachments thereto, shall be permitted to be released
upon agreement of the Promoters pursuant to Section 4 hereof.  Any copies which
are made will be marked "confidential," "proprietary" or with a similar legend.
Unless the parties agree otherwise, this obligation of confidentiality will
expire 3 years from the date of disclosure of such information hereunder.  A
party will not, however, be liable for the disclosure of any information which
is:

     a)   rightfully in the public domain other than by the recipient's breach
          of a duty;
     b)   rightfully received from a third party without any obligation of
          confidentiality; or

                                      -6-

 
                      HOME PHONELINE PROMOTER'S AGREEMENT
                      ----------------------------------- 


     c)   rightfully known to the recipient without any limitation on use or
          disclosure prior to its receipt from the disclosing party; or
     d)   independently developed by employees of the recipient without access
          to the disclosed information; or
     e)   rightfully disclosed as required by law; or
     f)   made public by unanimous agreement of the Promoters.

     5.2  Residuals.  This Agreement and the terms of confidentiality hereunder
          ---------                                                            
shall not be construed to limit any Promoter's right to independently develop or
acquire products or technology, including similar or competing products or
technology, without the use of another party's confidential information.  Any
party shall be free to use for any purpose the residuals resulting from access
to or work with the confidential information defined in Section 5.1, provided
that such party shall maintain the confidentiality of such confidential
information as provided herein.  The term "residuals" means information in non-
tangible form, which may be inadvertently retained by persons who have had
access to such confidential information, including ideas, concepts, know-how or
techniques contained therein.  No party shall have any obligation to limit or
restrict the assignment of such persons or to pay royalties for any work
resulting from the use of residuals.  However, the foregoing shall not be deemed
to grant to any party a license under the other party's copyrights or patents.

6.   WITHDRAWAL.

     6.1  Notice of Withdrawal.  A Promoter may, on written notice to the other
          --------------------                                                 
Promoters, withdraw from this Agreement.

     6.2  Effect of withdrawal.  Upon withdrawal by a Promoter:
          --------------------                                 

          (a) All covenants and licenses granted by and to such withdrawing
Promoter with respect to any final Specification adopted by the withdrawing
Promoter as of the date of such withdrawal shall continue in full force and
shall extend to and from entities who are or later become Adopters (and their
Affiliates as provided in the license), even after such withdrawal.  No covenant
or license shall be deemed granted or received or required to be granted by such
Promoter as to a new Specification or new revisions of the Specification adopted
after the date of such withdrawal, except as set forth in Section 6.2(c).  For
the avoidance of doubt, in the event any Promoter withdraws prior to the
publication of the first final version of the Specification, the covenants to
grant licenses are extinguished and of no effect.

          (b) A withdrawing Promoter must identify in its notice of withdrawal,
with reasonable specificity, any technical contribution it has made with regard
to any as yet unadopted revision or proposed update to the Specification being
considered at the time of withdrawal or to any Specification adopted within
thirty (30) days of such notice if such withdrawal is being done under 

                                      -7-

 
                      HOME PHONELINE PROMOTER'S AGREEMENT
                      ----------------------------------- 

Section 4.3(a). Any technical contribution not noticed will be licensed under
Sections 2.1 and 2.2. Additionally, the copyrights in any materials contributed
by such Promoter as of the time of withdrawal shall still be subject to the
provisions of Section 3.1 above.

          (c) The obligations of a withdrawn Promoter to license Necessary
Claims as set forth in Section 2 of this Agreement shall continue as to a new
Specification or revision if such new Specification or revision:  (i) defines a
network which is backwards compatible to a prior Specification for which the
Promoter is obligated to grant licenses, and (ii) uses a Necessary Claim in a
substantially similar manner and to a substantially similar extent as the
Necessary Claim was used in a prior Specification for which the Promoter is
obligated to grant licenses.  In no event is a withdrawn Promoter obligated to
license any additional Necessary Claims under this subsection.

7.   GENERAL.

     7.1  No Other Licenses.  Except for the rights expressly provided by this
          -----------------                                                   
Agreement, no Promoter grants or receives, by implication, or estoppel, or
otherwise, any rights under any patents or other intellectual property rights.

     7.2  Limited Effect.  This Agreement shall not be construed to waive any
          --------------                                                     
Promoter's rights under law or any other agreement except as expressly set out
here.

     7.3  No Warranty.  Promoter acknowledges that the Specification is provided
          -----------                                                           
"AS IS" WITH NO WARRANTIES WHATSOEVER, WHETHER EXPRESS, IMPLIED OR STATUTORY,
INCLUDING, BUT NOT LIMITED TO ANY WARRANTY OF MERCHANTABILITY, NONINFRINGEMENT,
FITNESS FOR ANY PARTICULAR PURPOSE, OR ANY WARRANTY OTHERWISE ARISING OUT OF ANY
PROPOSAL, SPECIFICATION, OR SAMPLE.

     Notwithstanding the above, each Promoter warrants that the Promoter has not
contributed any third party confidential information to the Specification and
that it has the authority to enter into this Agreement.

     7.4  Damages.  In no event will Promoters be liable to each other for any
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loss of profits, loss of use, incidental, consequential, indirect, or special
damages arising out of this Agreement or any Adopter or Participant agreements
related hereto, whether or not such party had advance notice of the possibility
of such damages.

     7.5  Notices.  Shall be sent to:
          -------                    

Compaq Computer Corporation
20555 SH 249

                                      -8-

 
                      HOME PHONELINE PROMOTER'S AGREEMENT
                      ----------------------------------- 

Houston, TX  77070
Attn:  General Counsel

IBM Corporation
Rt. 100
Somers, NY  10589
ATTN:  Peter Hortensius (801/291)
Director, Technology Development

Hewlett-Packard Company
Home Products Division
10500 Ridgeview Court
Cupertino, CA  95015-4010
ATTN:  R&D Manager

Advanced Micro Devices, Inc.
1160 Kern
Sunnyvale, CA  94086
Attn:  General Counsel

Intel Corporation
Post Contract Management MS JF3 - 149
2111 N.E. 25th Ave.
Hillsboro, Oregon  97124
Attn:     MDPO Counsel
    MS JF3-147

Tut Systems, Inc.
2495 Estand Way
Pleasant Hill, CA  94523
Attn:  Chief Financial Officer

Epigram, Inc.
870 W. Maude Ave.
Sunnyvale, CA  94086
ATTN:  Chief Financial Officer

AT&T Wireless Services Inc.
14520 N.E. 87th Street
Redmond, WA  98052
Attn:  Cynthia Hayward

                                      -9-

 
                      HOME PHONELINE PROMOTER'S AGREEMENT
                      ----------------------------------- 

V.P. - Chief Technology Counsel


3Com Corporation
5400 Bayfront Plaza
Santa Clara, California  95052
Attention:  General Counsel

Rockwell Semiconductor Systems, Inc.
4311 Jamboree Road
Newport Beach, CA 92660
Attn:  Kem McClelland
Dir. of Contracts & Technology Portfolio Management

Lucent Technologies Inc.
Microelectronics Group
Law Division
2 Oak Way
Berkeley Heights, NJ  07922
Attention:  John W. Fisher
Corporate Counsel

     7.6  Governing Law.  This Agreement shall be construed and controlled by
          -------------                                                      
the substantive laws of New York without reference to conflict of laws
principles.  Any litigation arising out of this Agreement shall take place in
New York, and all parties irrevocably consent to jurisdiction of the state and
Federal courts there.

     7.7  Not Partners.  The Promoters are independent companies and are not
          ------------                                                      
partners or joint venturers with each other.  While the Promoters may select an
entity to handle certain administrative tasks for them, no party is authorized
to make any commitment on behalf of all or any of them.

     7.8  Complete Agreement.  This Agreement sets forth the entire
          ------------------                                       
understanding of the parties and supersedes all prior agreements and
understandings relating hereto.  No modifications or additions to or deletions
from this Agreement shall be binding unless accepted in writing by an authorized
representative of all parties.

     7.9  Termination:  This agreement continues for each Promoter until
          -----------                                                   
terminated with respect to such Promoter upon events such as withdrawal or
default.

     7.10 Publicity:  No Promoter may make any statement on behalf of the Home
          ---------                                                           
PhoneLine alliance, without the prior approval of all of the Promoters.

                                      -10-

 
                      HOME PHONELINE PROMOTER'S AGREEMENT
                      ----------------------------------- 

     7.11 Execution in Counterparts.  This Agreement may be executed in any
          -------------------------                                        
number of counterparts, each of which when so executed and timely delivered
shall be deemed an original, and such counterparts together shall constitute one
instrument.

8.   COMPLIANCE WITH ANTITRUST LAWS.

     Each Promoter acknowledges that the Promoters are committed to fostering
competition in the development of new products and services based on the
Specification.  The Promoters further acknowledge that they may compete with one
another in various lines of business and that it is therefore imperative that
they and their representatives act in a manner which does not violate any
applicable antitrust laws and regulations.  Without limiting the generality of
the foregoing, the Promoters acknowledge that the Promoters will not discuss
issues relating to product costs, product pricing, methods or channels of
product distribution, any division of markets, or allocation of customers or any
other topic which should not be discussed among competitors.  Accordingly, each
Promoter hereby assumes responsibility to provide appropriate legal counsel to
its representatives acting under this Agreement regarding the importance of
limiting their discussions to subjects that relate to the purposes of the
Agreement, whether or not such discussions take place during formal meetings,
informal gatherings, or otherwise.

                                      -11-

 
                      HOME PHONELINE PROMOTER'S AGREEMENT
                      ----------------------------------- 

     IN WITNESS of their agreement, the Promoters have executed this Agreement
below:

Compaq Computer Corporation

By:________________________________     IBM Corporation                     
                                                                            
Name:______________________________     By:_______________________________
                                                                            
Title:_____________________________     Name:_____________________________  
                                                                            
Date:______________________________     Title:____________________________
                                                                            
Advanced Micro Devices, Inc.            Date:_____________________________  
                                                                            
By:________________________________     Lucent Technologies Inc.            
                                                                            
Name:______________________________     By:_______________________________
                                                                            
Title:_____________________________     Name:_____________________________
                                                                            
Date:______________________________     Title:____________________________
                                                                            
Tut Systems, Inc.                       Date:_____________________________
                                                                            
By:________________________________     Epigram, Inc.                       
                                                                            
Name:______________________________     By:_______________________________
                                                                            
Title:_____________________________     Name:_____________________________  
                                                                            
Date:______________________________     Title:____________________________  
                                                                            
3Com Corporation                        Date:_____________________________   
                                                                            
By:________________________________     Rockwell Semiconductor Systems, Inc.
                                                                            
Name:______________________________     By:_______________________________   
                                                                            
Title:_____________________________     Name:_____________________________  
                                                                            
Date:______________________________     Title:____________________________

                                      -12-

 
                      HOME PHONELINE PROMOTER'S AGREEMENT
                      ----------------------------------- 
                                                                            
Date:______________________________     Intel Corporation 
                                                          
                                        By:_______________________________
Hewlett-Packard Company                                   
                                        Name:_____________________________
By:________________________________                       
                                        Title:____________________________
Name:______________________________                       
                                        Date:_____________________________
Title:_____________________________

Date:______________________________

AT&T Wireless Services Inc.

By:________________________________

Name:______________________________

Title:_____________________________

Date:______________________________

                                      -13-

 
This is a patent license agreement among parties wishing to adopt the Home
Phoneline Specification

                                  ATTACHMENT A

                              ADOPTER'S AGREEMENT

AS USED IN THIS AGREEMENT:

 .    The "PROMOTERS" are IBM Corporation, Hewlett-Packard Company, Compaq
     Computer Corporation, Advanced Micro Devices, Inc., Intel Corporation, Tut
     Systems, Inc., Epigram, Inc., AT&T Wireless Services Inc., 3Com
     Corporation, Rockwell Semiconductor Systems, Inc. and Lucent Technologies
     Inc. and their Affiliates.

 .    "ADOPTER" is the entity named at the end of this Agreement.

 .    "FELLOW ADOPTERS" are the Adopters who have executed an identical
     counterpart of this Agreement and delivered it to the Promoters.

 .    "AFFILIATE" is an entity that directly or indirectly controls, is
     controlled by, or is under common control with another entity, so long as
     such control exists.  This definition of Affiliate is modified for AT&T
     Wireless Services Inc. to mean only directly or indirectly controls another
     entity, as long as such control exists.  "Control" means beneficial
     ownership of more than fifty percent of the voting stock or equity in an
     entity.

 .    "NECESSARY CLAIMS" shall mean those claims of all patents, other than
     design patents and design registrations, throughout the world entitled to
     an effective filing date prior to January 1, 2003, which a Promoter or
     Adopter, as applicable, or its Affiliates has the right, at any time during
     the term of this Agreement, to grant licenses of the scope granted herein
     without such grant or the exercise of rights thereunder resulting in
     payment of royalties or other consideration to third parties (except for
     payments to Affiliates or to employees within the scope of their
     employment) and (i) which are necessarily infringed by an implementation of
     a version of the Specification adopted by the Promoters, where such
     infringement could not have been avoided by another commercially reasonable
     noninfringing implementation of such Specification, or (ii) for which
     infringement is based on an implementation of any example included in the
     body of the Specification.  Necessary Claims shall not include, and no
     license shall apply to, implementation examples included solely in any
     appendix, exhibit or other attachment to the actual Specification.

 .    "SPECIFICATION" means the document entitled Home Phoneline authored and
     published by the Promoters and updates thereto.

 .    "FULLY COMPLIANT" means:  (a) an implementation of the Specification which
     supports or implements all of the portions of the Specification defined by
     the Specification as being 

 
     "Required" or (b) an implementation of all portions of the Specification
     required for a specific type of product or component thereof.

 .    "SECRETARY" shall mean the Promoter chosen to administrate the
     Specification as the Promoters may determine from time to time.  As of the
     effective date of this Agreement, the Secretary is Compaq.

LICENSES:

     Grants of Licenses.  The following license has been granted by the
     ------------------                                                
Promoters to all Adopters. Upon Adopter's execution of this Agreement, the
agreement to license is granted by Adopter to all Fellow Adopters (including the
Promoters), and the grants of all Fellow Adopters shall extend to Adopter.  In
each case, the party (Promoter, Adopter, or Fellow Adopter) and its Affiliates
granting the covenant is referred to as the "Licensor."

     Upon agreement by the Promoters as to the final version of the text of the
     Specification, Licensor hereby covenants to grant to each Promoter and its
     Affiliates and to each Fellow Adopter and its Affiliates under reasonable
     terms and conditions that are demonstrably free of any unfair
     discrimination, a nonexclusive, nontransferable, nonsublicenseable (except
     as part of the transfer of an end user product), worldwide license under
     its Necessary Claims to implement the Specification and to make, have made,
     use, import, offer to sell, lease, sell, promote and otherwise distribute
     the resulting implementation (whether implemented in hardware, software, or
     some combination of hardware and software); provided, however, (i) the
     resulting implementation is Fully Compliant, (ii) such license shall not
     extend to features of a product which are not required to comply with the
     Specification or to other specifications and APIs (Application Programming
     Interfaces), such as a Promoter's operating system API, and (iii) such
     license shall be granted only to the extent that the resulting
     implementation is used for the purposes of home or LAN networking over home
     or any single pair in-premises telephone lines.  To the extent an Adopter
     becomes aware of any Necessary Claims which are or will be subject to the
     above license and to the extent that an Adopter intends to seek a
     reasonable royalty for such Necessary Claims pursuant to the above license,
     such Adopter shall promptly notify the Secretary of such Necessary Claims.
     Additionally, to the extent an Adopter becomes aware of claims which would
     be Necessary Claims but for the obligation to pay royalties or other
     consideration to third parties, the Adopter shall promptly notify the
     Secretary of such claims.

 .    Acceptance of Licenses.  Adopter hereby accepts the agreement to make
     ----------------------                                               
     available Licenses granted by the Fellow Adopters.

 .    Withdrawal.  Adopter may withdraw at any time by providing written notice
     ----------                                                               
     to the Secretary. The effect of such withdrawal is that the withdrawing
     Adopter's existing licenses and agreement to grant licenses, with respect
     to a Specification published by the Promoters more than sixty (60) days
     prior to the date of withdrawal, shall continue in full force and shall
     extend to or be extended to entities who become Adopters and their
     Affiliates as provided in 

                                      -2-

 
     the license even after such withdrawal. Further, the licenses granted to
     such Adopter shall continue to apply with respect to the Specification and
     any Updates published by the Promoters more than sixty (60) days prior to
     the date of withdrawal. No license or agreement to license shall be deemed
     granted or received by such Adopter as to the Specification revision
     published less than sixty (60) days prior to or after the date of such
     withdrawal. The obligations of a withdrawn Adopter to license Necessary
     Claims as set forth in this Agreement shall continue as to a new
     Specification or revision if such new Specification or revision: (i)
     defines a network which is backwards compatible to a prior Specification
     for which the Adopter is obligated to grant licenses, and (ii) uses a
     Necessary Claim in a substantially similar manner and to a substantially
     similar extent as the Necessary Claim was used in a prior Specification for
     which the Adopter is obligated to grant licenses. In no event is a
     withdrawn Adopter obligated to license any additional Necessary Claims
     under this subsection.

 .    Trademarks.  The Adopter and its Affiliates hereby agree not to assert
     ----------                                                            
     against any Promoter or any Fellow Adopter any trademark or trade name
     rights they may have now or hereafter in any name or logo adopted by the
     Promoters for use in connection with such Specification. Prior to adoption
     of a new name or logo, the Promoters shall transmit a proposed name or logo
     to Adopter.  Adopter shall have 30 days to notify the Secretary if it
     possesses any rights to such name or logo.  Failure to respond within such
     30 days will waive any rights of Adopter to such proposed name or logo.
     The Adopter and its Affiliates will not use the name or logo adopted by the
     Promoters except to refer to the Specification and to products which fully
     comply with the Specification.

GENERAL:

 .    No Other Licenses.  Adopter neither grants nor receives any license to or
     -----------------                                                        
     right to use any trademark, tradename, copyright, or maskwork hereunder.
     Except for the rights expressly provided by this Agreement, Adopter neither
     grants nor receives, by implication, or estoppel, or otherwise, any rights
     under any patents or other intellectual property rights.

 .    No Warranty.  Adopter acknowledges that the Specification is provided "AS
     -----------                                                              
     IS" WITH NO WARRANTIES WHATSOEVER, WHETHER EXPRESS, IMPLIED OR STATUTORY,
     INCLUDING, BUT NOT LIMITED TO ANY WARRANTY OF MERCHANTABILITY,
     NONINFRINGEMENT, FITNESS FOR ANY PARTICULAR PURPOSE, OR ANY WARRANTY
     OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION, OR SAMPLE.

 .    Damages.  In no event will Promoters, Adopter or Fellow Adopters be liable
     -------                                                                   
     to the other for any loss of profits, loss of use, incidental,
     consequential, indirect, or special damages arising out of this Agreement,
     whether or not such party had advance notice of the possibility of such
     damages.

                                      -3-

 
 .    Governing Law.  This Agreement shall be construed and controlled by the
     -------------                                                          
     substantive laws of New York without reference to conflicts of laws
     principles.  Any litigation arising out of this Agreement shall take place
     in New York, and all parties irrevocably consent to jurisdiction of the
     state and Federal courts there.

 .    Not Partners.  Adopter understands that the Promoters are independent
     ------------                                                         
     companies and are not partners or joint venturers with each other.  While
     the Promoters may select an entity to handle certain administrative tasks
     for them, no party is authorized to make any commitment on behalf of all or
     any of them.

 .    Promoters as Beneficiaries.  While only a single Promoter has executed
     --------------------------                                            
     this Agreement with Adopter, Adopter understands that all of the Promoters
     are beneficiaries of this Agreement and any Promoter is entitled to enforce
     its terms against Adopter.

 .    Complete Agreement.  This Agreement sets forth the entire understanding of
     ------------------                                                        
     the agreement between the Adopters and the Promoters and supersedes all
     prior agreements and understandings relating hereto.  No modifications or
     additions to or deletions from this Agreement shall be binding unless
     accepted in writing by an authorized representative of all parties.

 .    Execution in Counterparts.  This Agreement may be executed in any number
     -------------------------                                               
     of counterparts, each of which when so executed and timely delivered shall
     be deemed an original, and such counterparts together shall constitute one
     instrument.

 .    Effective Date.  This Agreement shall be legally binding when:
     --------------                                                

     1)   the Promoter has signed the Agreement,
     2)   the Adopter has signed the Agreement, and
     3)   the Agreement has been received via overnight courier to the attention
          of the Secretary at

          Home Phoneline Adopter's Agreement Administration
          Compaq Computer Corporation
          20555 SH 249
          Houston, TX  77070

 .    Notices.  All notices under this Agreement shall be sent to:
     -------                                                     

     If to the Promoters:                     If to Adopter:
          Home Phoneline Adopter's                    __________________________
            Agreement Administration                  __________________________
          Compaq Computer Corporation                 __________________________
          20555 SH 249                                __________________________
          Houston, TX  77070                          __________________________

                                      -4-

 
     With a copy to:
          Compaq Computer Corporation
          20555 SH 249
          Houston, TX  77070
          Attn:  General Counsel


Adopter:                            Promoter:



By:__________________________         By:___________________________


Name:________________________         Name:_________________________


Title:_______________________         Title:________________________


Date:________________________          Date:________________________



                                      -5-

 
                                  ATTACHMENT B

                            PARTICIPANT'S AGREEMENT

     Certain Promoters are developing a specification (the "Specification")
defining a home networking system using telephone lines.  The Specification may
become appropriate for industry-wide adoption and the Promoters seek the
counsel, advice, and input of Participant.  In order to facilitate consultations
between the Promoters and Participant, this Agreement sets out the legal terms
that will govern those consultations.

     As used herein, "Promoters" means IBM Corporation, Hewlett-Packard Company,
Compaq Computer Corporation, Advanced Micro Devices, Inc., Intel Corporation,
Tut Systems, Inc., Epigram, Inc., AT&T Wireless Services Inc., 3Com Corporation,
Rockwell Semiconductor Systems, Inc., and Lucent Technologies Inc.
"Participant" refers to the industry participant named below and its Affiliates.
"Affiliate" is an entity that directly or indirectly controls, is controlled by,
or is under common control with another entity, so long as such control exists.
This definition of Affiliate is modified for AT&T Wireless Services Inc. to mean
only directly or indirectly controls another entity, as long as such control
exists.  "Control" means beneficial ownership of more than fifty percent of the
voting stock or equity in an entity.

     CONSULTATION.  Any Promoter and Participant may consult with each other on
the content, feasibility, and other aspects of one or more revisions of the
Specification.  The Promoters shall be free to incorporate the suggestions of
Participant into the Specification.

     IN CONFIDENCE.  Participant will maintain the non-final versions of the
Specification in confidence with at least the same degree of care that it uses
to protect its own confidential and proprietary information, but no less than a
reasonable degree of care under the circumstances and will neither disclose nor
copy the non-final versions of the Specification except as necessary for its
employees and contractors (under obligation of confidentiality) with a need to
know for the purposes of developing or updating the Specification.  Any copies
which are made will be marked "confidential," "proprietary" or with a similar
legend.  Unless the parties agree otherwise, this obligation of confidentiality
will expire 3 years from the date of disclosure to Participant.  Participant
will not, however, be liable for the disclosure of any information that is:

     a)   rightfully in the public domain other than by Participant's breach of
          a duty;
     b)   rightfully received from a third party without any obligation of
          confidentiality; or
     c)   rightfully known to the Participant without any limitation on use or
          disclosure prior to its receipt from the disclosing party; or
     d)   independently developed by employees of the Participant without access
          to the disclosed information; or
     e)   rightfully disclosed as required by law; or
     f)   inherently disclosed in the marketing or sale of a product or service.

 
     Any party shall be free to use for any purpose the residuals resulting from
access to or work with the confidential information defined above, provided that
such party shall maintain the confidentiality of such confidential information
as provided herein.  The term "residuals" means information in non-tangible
form, which may be inadvertently retained by persons who have had access to such
confidential information, including ideas, concepts, know-how or techniques
contained therein.  No party shall have any obligation to limit or restrict the
assignment of such persons or to pay royalties for any work resulting from the
use of residuals.  However, the foregoing shall not be deemed to grant to any
party a license under the other party's copyrights or patents.

     LICENSING.  The Promoters intend to license the right to implement the
final version of the Specification to all interested industry members on a
nondiscriminatory, reciprocal, reasonable basis. The Promoters have the right to
disclose the Specification in draft and in final form, including Participant's
suggestions to the Promoters.

     Upon agreement by the Promoters as to the final version of the text of the
Specification, with respect to any suggestion or improvement to the
Specification made by Participant and incorporated in the Specification,
Participant and its Affiliates hereby covenants to grant to each Promoter and
its Affiliates and to each Adopter and its Affiliates under reasonable terms and
conditions that are demonstrably free of any unfair discrimination, a
nonexclusive, nontransferable, nonsublicenseable (except as part of the transfer
of an end user product), worldwide license under its Necessary Claims to
implement the Specification and to make, have made, use, import, offer to sell,
lease, sell, promote and otherwise distribute the resulting implementation
(whether implemented in hardware, software, or some combination of hardware and
software); provided, however, (i) the resulting implementation is Fully
Compliant, (ii) such license shall not extend to features of a product which are
not required to comply with the Specification or to other specifications and
APIs (Application Programming Interfaces), such as a Promoter's operating system
API, and (iii) such license shall be granted only to the extent that the
resulting implementation is used for the purposes of home or LAN networking over
home or any single pair in-premises telephone lines.  To the extent a
Participant becomes aware of any Necessary Claims which are or will be subject
to the above license and to the extent that a Participant intends to seek a
reasonable royalty for such Necessary Claims pursuant to the above license, such
Participant shall promptly notify the Secretary of such Necessary Claims.  If
such notification is not provided prior to adoption of the version of the
Specification where such Necessary Claims develop, the Participant shall not
request an injunction for such Necessary Claims in connection with the
Specification as used by the Promoters and Adopters.  Additionally, to the
extent a Participant becomes aware of claims which would be Necessary Claims but
for the obligation to pay royalties or other consideration to third parties, the
Participant shall promptly notify the Secretary of such claims.

     Additionally, effective upon the Promoters' agreement as to any final
version of the Specification, Participant grants to the Promoters, under any
copyright, trade secret right or other non-patent intellectual property right in
or applying to such contribution, a non-exclusive, non-transferable, royalty-
free worldwide license, with rights to sublicense to all Promoters and Adopters
of the Specification, to make, have made, use, reproduce, prepare derivative
works of, perform, display, import, offer to sell and sell and otherwise
distribute products, whether hardware, software, 

                                      -2-

 
or some combination of hardware and software, which implement and comply with
the Specification so long as the product is Fully Compliant with such
Specification.

     "NECESSARY CLAIMS" shall mean those claims of all patents, other than
design patents and design registrations, throughout the world entitled to an
effective filing date prior to January 1, 2003, which a Participant, or its
Affiliates, has the right, at any time during the term of this Agreement, to
grant licenses of the scope granted herein without such grant or the exercise of
rights thereunder resulting in payment of royalties or other consideration to
third parties (except for payments to Affiliates or to employees within the
scope of their employment) and (i) which are necessarily infringed by an
implementation of a version of the Specification adopted by the Promoters, where
such infringement could not have been avoided by another commercially reasonable
noninfringing implementation of such Specification, or (ii) for which
infringement is based on an implementation of any example included in the body
of the Specification.  Necessary Claims shall not include, and no license shall
apply to, implementation examples included solely in any appendix, exhibit or
other attachment to the actual Specification.

     "FULLY COMPLIANT" means:  (a) an implementation of the Specification which
supports or implements all of the portions of the Specification defined by the
Specification as being "Required" or (b) an implementation of all portions of
the Specification required for a specific type of product or component thereof.

     FELLOW PARTICIPANTS.  The Promoters may invite additional parties to become
"Fellow Participants" by execution by those additional parties of a
Participant's Agreement identical to this agreement.  When a Promoter identifies
such a Fellow Participant, the Participant shall be free to exchange information
relating to the non-final versions of the Specification with such party, and
such information shall be treated as confidential as provided above.

     TRADEMARKS AND BRANDING.  The Participant hereby agrees not to assert
against any Promoter or any Fellow Adopter any trademark or trade name rights
they may have now or hereafter in any name or logo adopted by the Promoters for
use in or with such Specification.  Prior to adoption of a new name or logo, the
Promoters shall transmit a proposed name or logo to Participant. Participant
shall have 30 days to notify the Secretary if it believes it possesses any
rights to such name or logo.  Failure to respond within such 30 days will waive
any rights of Participant to such proposed name or logo.  The Participant will
not use the name or logo adopted by the Promoters except to refer to the
Specification and to products which fully comply with the Specification.

     EARLY TERMINATION.  A party may terminate this agreement as to itself at
any time without cause upon written notice to the other.  All obligations of
confidentiality, and the license granted above, will survive the termination of
this agreement.

     GENERAL.  This Agreement does not create a joint venture, partnership or
other form of business association between the parties, nor an obligation to buy
or sell products implementing the draft Specification or its final version.
This Agreement will be governed by the substantive laws of New York without
reference to conflict of laws principles.  Participant understands that all of
the 

                                      -3-

 
Promoters are intended third party beneficiaries of this Agreement and may
enforce the provisions thereof against Participant.  This Agreement may be
executed in any number of counterparts, each of which when so executed and
timely delivered shall be deemed an original, and such counterparts together
shall constitute one instrument.  Each Participant warrants that the Participant
has not contributed any third party confidential information to the
Specification and that it has the authority to enter into this Agreement.

EFFECTIVE DATE.  This Agreement shall be legally binding when:

     1)   the Promoter has signed the Agreement,
     2)   the Participant has signed the Agreement, and
     3)   the Agreement has been received via overnight courier to the attention
          of the Secretary at

          Home Phoneline Participant's Agreement Administration
          Compaq Computer Corporation
          20555 SH 249
          Houston, TX  77070

NOTICES.  All notices under this Agreement shall be sent to:

     If to the Promoters:                     If to Participant:
          Home Phoneline Participant's           ____________________________
            Agreement Administration             ____________________________
          Compaq Computer Corporation            ____________________________
          20555 SH 249                           ____________________________
          Houston, TX  77070                     ____________________________

     With a copy to:
          Compaq Computer Corporation
          20555 SH 249
          Houston, TX  77070
          Attn:  General Counsel


                                      -4-

 
AGREED:


PARTICIPANT                         PROMOTER


Corp Name:______________________        Corp Name:________________________


Signed:_________________________        Signed:___________________________


Name:___________________________        Name:_____________________________


Title:__________________________        Title:____________________________


Date:___________________________        Date:_____________________________


     With a copy to:
          Compaq Computer Corporation
          20555 SH 249
          Houston, TX  77070
          Attn:     Group Counsel,
                    Communication Products

          Intel Corporation
          2111 N.E. 25th Ave.
          Hillsboro, Oregon   97124
          Attn:     MDPO Counsel
                    MS JF3-147

          Microsoft Corporation
          One Microsoft Way
          Redmond, WA  98052
          Attn:  Assoc. Gen. Counsel (IP)


                                      -5-

 
ADOPTER:                            PROMOTER:


By:_________________________            By:___________________________


Name:_______________________            Name:_________________________


Title:______________________            Title:________________________


Date:_______________________            Date:_________________________




                                      -6-