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                                                                   EXHIBIT 10.18

                        CONFIDENTIAL TREATMENT REQUESTED

                         MASTER HIGH SPEED DATA SERVICES
                                    AGREEMENT

       THIS MASTER HIGH SPEED DATA SERVICES AGREEMENT (this "Master Agreement")
is entered into as of the 22nd day of June 1999, by and between I(3)S, Inc., a
Texas corporation, with a place of business at 1440 Corporate Drive, Irving
Texas 75038 ("I3S"); and SEREN INNOVATIONS, INC., a Minnesota corporation with a
place of business at 15 South 5th Street, Suite 500, Minneapolis, MN 55402
("SEREN"). I3S and SEREN are hereinafter sometimes individually referred to as a
"party", and collectively as the "parties".

                                    RECITALS

       WHEREAS, SEREN is developing multiple franchise cable television systems
(collectively, "MSOs") in various markets throughout the United States;

       WHEREAS, I3S provides broadband Internet protocol network Services,
including, without limitation, those high speed data services, which are more
specifically described in the Exhibits attached hereto and incorporated herein
by reference (the "HSDS"), to multiple system franchise cable operators
nationwide; and

       WHEREAS, SEREN and I3S desire to exclusively provide HSDS to the Hybrid
Fiber Coaxial System (HFC) Networks owned or operated by SEREN, and listed in
Exhibit C, pursuant to the terms and provisions of this Agreement which, in
part, gives I3S an exclusive right of access to provide HSDS to such HFC
Networks.

       NOW, THEREFORE, the parties hereto hereby covenant and agree as follows:

                                    ARTICLE 1
                         REPRESENTATIONS AND WARRANTIES

       1.1    REPRESENTATIONS AND WARRANTIES OF SEREN.

       AUTHORITY.  This Agreement has been duly authorized, executed and
delivered by SEREN and constitutes a valid and legally binding Agreement of
SEREN, and neither the execution and delivery, nor the performance, of the
provisions of this Agreement shall conflict with or result in (a) a breach,
violation or default under the Certificate of Incorporation and Bylaws of SEREN,
if applicable; or any material agreement binding on SEREN that would affect its
obligations hereunder; or (b) the breach or violation of any law, order, rule,
ordinance, regulation, judgement or decree of an governmental authority having
jurisdiction.

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       SURVIVAL OF REPRESENTATIONS AND WARRANTIES.  All representations and
warranties made by or on behalf of SEREN shall survive the execution and
delivery of this Agreement, and any investigation at any time made by or on
behalf of I3S shall not diminish its rights to rely thereon.

       1.2    REPRESENTATIONS AND WARRANTIES OF I3S.

       AUTHORITY.  This Agreement has been duly authorized, executed and
delivered by I3S and constitutes a valid and legally binding Agreement of I3S,
and neither the execution and delivery, nor the performance, of the provisions
of this Agreement shall conflict with or result in (a) a breach, violation or
default under the Certificate of Incorporation and Bylaws of I3S, if applicable;
or any material agreement binding on I3S that would affect its obligations
hereunder; or (b) the breach or violation of any law, order, rule, ordinance,
regulation, judgement or decree of an governmental authority having
jurisdiction.

       PERMITS, LICENSES, ETC. I3S possesses all material permits, licenses,
franchises rights, trademarks, trademark rights, trade names, trade name rights
and copyrights which are required to conduct the business of HSDS.

       I3S LICENSES. I3S possesses all requisite licenses from third parties
necessary to provide the HSDS to the HFC Network.

       SURVIVAL OF REPRESENTATIONS AND WARRANTIES. All representations and
warranties made by or on behalf of I3S shall survive the execution and
delivery of this Agreement, and any investigation at any time made by or on
behalf of SEREN shall not diminish its rights to rely thereon.

                                    ARTICLE 2
                                      TERM

       2.1   TERM.  This Master Agreement shall have an initial term of ten
(10) years from the Effective Date; provided, however, that the initial term may
be automatically extended after the tenth anniversary of the Effective Date for
additional one (1) year terms unless one party provides the other party with
prior written notice, delivered no earlier than 180 days prior to the expiration
of initial term (or any renewal thereof) of this Master Agreement, of the
notifying party's intent to terminate this Master Agreement. Notwithstanding
anything contained in this Section 2.1 to the contrary, with respect to the HFC
Network pertaining to St. Cloud, Minnesota, the initial term of this HFC Network
Agreement shall be seven (7) years from the Effective Date. With respect to each
additional HFC Network that becomes subject to this Agreement, the initial term
of this Agreement pertaining thereto shall be either the later of (i) six (6)
years commencing on the date that the HSDS are first provided at said HFC
Network, or (ii) five (5) years commencing on the date that SEREN completes the
construction of the two-way hybrid fiber coaxial cable distribution plant past
100,000 prospective HSDS subscribers.

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                                    ARTICLE 3
                                   EXCLUSIVITY

       3.1    EXCLUSIVITY. During the term of this Agreement, neither party
shall provide, market or support, or cause to be provided, marketed or
supported, directly or indirectly, a competitive service to HSDS which is
deployed over the I3S national IP backbone to said HFC Network franchise service
area except in accordance with the terms and conditions hereof; provided,
however, that (i) for HFC Networks listed in Exhibit C at the date of signing
this Master Agreement, I3S shall not be precluded from providing HSDS under
other agreements with third parties that have been entered into prior to the
date of signing this Master Agreement; (ii) for future Seren HFC Networks not
listed in Exhibit C at the date of signing this Master Agreement, I3S shall not
be precluded from providing HSDS under other agreements with third parties that
have been entered into prior to the date that said HFC Network(s) is added by
amendment to Exhibit C; and (iii) SEREN shall not be precluded from receiving
long haul IP backbone services from Qwest and Means pursuant to the terms of the
respective agreements between SEREN and said third parties entered into prior to
the date of signing this Master Agreement.

       3.2    I3S RIGHT OF FIRST REFUSAL. I3S shall have a right of first
refusal to provide broadband data services not defined as HSDS hereunder in the
event that SEREN decides to offer such services at a HFC Network covered by this
Agreement. In the event that SEREN does not select I3S to provide any such
broadband data services, but either provides them itself or from a third party,
then SEREN and I3S shall agree, in good faith, to establish a mutually
acceptable means of compensation for I3S to the extent that any such broadband
data services require the use of assets owned by I3S hereunder. The decision to
accept or reject any such proposal from I3S or the timing thereof, is totally
within the discretion of Seren.

       3.3    SEREN'S RIGHT OF FIRST REFUSAL. SEREN shall have the right to
receive broadband data services not defined as HSDS hereunder from I3S in the
event that I3S decides to offer such services at a HFC Network covered by this
Agreement on terms and conditions mutually acceptable to the Parties.

                                    ARTICLE 4
                               SEREN'S OBLIGATIONS

       4.1    GENERAL OBLIGATIONS. In consideration of the mutual agreements of
the parties contained herein, SEREN expressly covenants and agrees to do and
perform, or cause to be done and performed, the following:

       (i)    SEREN grants I3S an exclusive right to provide HSDS as more
particularly set forth in Exhibit B attached hereto and incorporated herein by
reference to the HFC Network; and

       (ii)   SEREN shall, at its own expense, provide and maintain the
equivalent of at least four (4) video channels worth of bandwidth, or as
mutually agreed to by the Parties from time to

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time, on the cable antennae distribution facilities (the "System") at the HFC
Network headend to provide the HSDS; and

       (iii)  SEREN shall, at its own expense, operate and maintain the video or
telecommunications headend to the specifications described in Exhibit B (the
"Specifications") sufficient to ensure that the HSDS are properly delivered over
the local loop; and shall assume the operating and capital cost of the
following:

                   o  Monthly recurring local loop costs to the HFC Network
                      headend;
                   o  Monthly recurring property maintenance (Lce, Router);
                   o  Monthly recurring IP headend maintenance;
                   o  Customer Service Representative platform;
                   o  Internet browser platform user license;
                   o  HFC Network property IP equipment (Lce, Router);
                   o  Non-recurring local loop transport costs;
                   o  Customer billing and collections;
                   o  Subscriber premise equipment installation and maintenance;
                   o  Tier 1 customer care and support; and
                   o  Co-location facilities and HSDS CMTS or xDSLAM, and
                      related equipment, at each HFC Network headend or
                      telecommunications central office

       (iv)   after the initial training by I3S as provided for herein, SEREN
shall pay the cost for training its own personnel to maintain the System up to
the Specifications; and

       (v)    SEREN shall maintain commercial general liability insurance with
minimum limits of not less than $1,000,000 per occurrence for bodily injury (or
death) and property damage liability with limits of at least $1,000,000 per
occurrence [Personal Injury and $1,000,000 General Policy Aggregate (applicable
to Commercial General Liability Policies)] which names I3S as an additional
insured; and

       (vi)   on behalf of I3S, SEREN shall secure access to all properties of
SEREN as necessary to provide the HSDS; and

       (vii)  the employees, agents, or contractors of I3S shall have reasonable
access, at no charge, to the HFC Network and facilities of SEREN in connection
with and to perform any and all work reasonably necessary to provide the HSDS at
the HFC Network, including, but not limited to, installation, inspection,
maintenance, repair or removal of equipment, or to facilitate the provision of
the HSDS to customers; and

       (viii) each party's employees, contractors, or agents will, while on the
premises of any other party, comply with all applicable law and regulations and
any reasonable written rules or regulations of SEREN applicable to all tradesmen
or contractors on the premises; and

       (ix)   all revenue sharing or other payments to SEREN for discharging its
obligations hereunder shall be as set forth herein. I3S shall have no other
obligation to pay any revenue

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shares, commissions, or other consideration to SEREN in connection with the
provision of HSDS; and

       (x)    any and all maintenance or other problems with respect to I3S'
obligations set forth in Exhibit B (HSDS Service Level Agreement) hereunder will
be reported directly to I3S to the point of contact designated in writing by I3S
(the "Contact") for resolution by I3S; and

       (xi)   SEREN will provide a secure air-conditioned space, at no charge,
to I3S for the storage of all equipment reasonably necessary to provide the HSDS
at the HFC Network Headend; and

       (xii)  SEREN will provide electricity necessary to power I3S co-located
equipment; and

       4.2    MARKETING. SEREN and I3S will consult and develop a joint
marketing strategy designed to co-brand and promote the HSDS hereunder.

                                    ARTICLE 5
                          AFFIRMATIVE COVENANTS OF I3S

       5.1    GENERAL OBLIGATIONS. In consideration of the mutual agreements of
the parties contained herein, I3S covenants and agrees to do and perform, or
cause to be done and performed, the following:

       (i)    I3S possesses and shall maintain for the term of this Agreement
any and all property, right, title or interest necessary to lawfully provide the
HSDS as contemplated in this Agreement, and all such property, right, title and
interest shall remain free and clear of any adverse claims, interests and liens.

       (ii)    I3S possesses and shall maintain in full force and effect for the
term of this Agreement, all material permits, licenses, franchise rights,
trademarks, trademark rights, trade names, trade name rights and copyrights
which are required to provide the HSDS.

       (iii)  With respect to performance hereunder, I3S agrees to maintain, at
all times during the term of this Agreement, as a minimum, commercial general
liability insurance with minimum limits of $1,000,000 per occurrence for bodily
injury (or death) and property damage liability with limits of at least
$1,000,000 per occurrence [Personal Injury and $1,000,000 General Policy
Aggregate (applicable to Commercial General Liability Policies)] and any
additional insurance and/or bonds required by law. Upon request, I3S agrees to
furnish certificates or other acceptable proof of the foregoing insurance and
name SEREN as an additional insured and also name such Owners and Operators as
an additional insured who may request it. I3S warrants that it meets or exceeds
all insurance requirements stated herein and those that are required by the laws
in the State of Texas.

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       (iv)   As more specifically described in Exhibit A (description of HSDS
provided by I3S) attached hereto and incorporated herein by reference, I3S
shall assume and pay all operating and capital costs and expenses associated
with any and all:

                   Monthly recurring private Internet exchange points;
                   Monthly recurring switch maintenance;
                   Monthly recurring POP transport;
                   Monthly recurring Dallas network operations center costs
                   (including installation costs);
                   Customer support IP technicians and engineers (NOC
                   personnel);
                   I3S-specific training, to include HSDS system launch at the
                   HFC Network and integration support, customer premise
                   equipment installation, marketing and sales training for
                   residential and commercial services, Tier 1 customer care and
                   support training, and operational procedural training for the
                   Services;
                   Insurance on I3S capital equipment;
                   I3S-specific travel and entertainment;
                   Switch site equipment (including installation costs);
                   Peering point routers;
                   Private Internet exchange point
                   hardware (including installation costs);
                   I3S network infrastructure equipment;
                   Transport facilities to the HFC Network Headend;
                   Backbone transport facilities;
                   IP master headend equipment; and
                   Tier 2 and 3 customer care and IP engineering support
                   IP Addresses

       (v)    I3S shall activate a metropolitan Point of Presence within sixty
(60) days of receipt of written notification from SEREN that it is prepared to
commence the delivery of HSDS at a HFC Network.

       (vi)   Seren shall have operational responsibility for a DS-3 circuit
between I3S' metropolitan Point of Presence in Minneapolis, Minnesota and
SEREN's HFC Network CATV head end in St. Cloud, Minnesota; provided, however,
that I3S shall assume, and SEREN shall no longer pay, the monthly recurring cost
of said DS-3 circuit on the first (1st) day of the immediately succeeding month
that at least 2,500 subscribers are receiving HSDS at the HFC Network for St.
Cloud, Minnesota.

       (vii)  I3S understands and agrees that the Subscribers of the HSDS are
Seren's customers. I3S agrees that, except as described in Article 3.1, during
the term of this Agreement and for a period of six months during the transition
upon termination period set forth in Section 12.5 hereof, it shall not attempt
to solicit Seren's customers for HSDS or other similar services within the HFC
Network franchise service territory.

       (viii) Provide Seren with specific PC hardware and software subscriber
requirements.

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                                    ARTICLE 6
                            DESCRIPTION OF THE HSDS

       6.1    DESCRIPTION OF THE HSDS. During the term of this Agreement, I3S
shall provide, or cause to be provided, to HFC Networks, the HSDS, more
particularly described and set forth in Exhibit A attached hereto and
incorporated herein by reference.

                                    ARTICLE 7
                  DEFINITION OF HSDS SERVICE LEVEL STANDARDS

       7.1    DEFINITION OF SERVICE LEVEL STANDARDS. Subject to the conditions,
qualifications and limitations set forth herein, during the term of this
Agreement, I3S shall use its commercially reasonable efforts to offer, or cause
to be offered, the HSDS level standards pertaining to various aspects of the
HSDS, as more particularly described and set forth in Exhibit B attached hereto
and incorporated herein by reference.

                                    ARTICLE 8
          REVENUE ALLOCATION; CUSTOMER ACCESS PRICING; BRANDING

       8.1    REVENUE ALLOCATION. With respect to HSDS utilizing HFC cable modem
technology to serve Seren's customers, monthly recurring Internet access revenue
received from HSDS Subscribers at HFC Networks (the "Revenue") will be paid
directly by customers to SEREN; provided, however, that, by the twenty-fifth day
of each calendar month hereafter SEREN shall pay I3S a share of the Revenue in
an amount equal to **** of the Revenue; provided, however, that in no event
shall said share of the Revenue be less than ** per Subscriber per month; and
further provided, however, that in no event shall said share of the Revenue be
less than (i) ** per month upon achieving the first 1000 prospective HSDS
subscribers at an HFC Network, (ii) ** per month upon achieving at least **
prospective HSDS subscribers at said HFC Network, and (iii) ** per month upon
achieving at least ** prospective HSDS subscribers at said HFC Network, and at
all times thereafter, for each municipal cable television headend.

         With respect to HSDS utilizing technology other than HFC cable modem
technology to serve Seren customers, monthly recurring Internet access revenue
received from Subscribers (the "Revenue") will be paid directly to SEREN;
provided, however, that, by the twenty-fifth day of each calendar month
hereafter SEREN shall pay I3S a share of the Revenue in an amount equal to ****
** of the Revenue; provided, however, that in no event shall said share of the
Revenue be less than ** per Subscriber per month.

         In addition to its ability to terminate as provided for in Article 12,
in the event that I3S fails to meet the SLA standards of Exhibit B, for any
given month, Seren shall be relieved from paying the monthly revenue minimums
identified above.

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       8.2    CUSTOMER ACCESS PRICING. With the intent to increase HSDS
penetration at each HFC Network, SEREN, in consultation with I3S shall establish
the price at which access to the HSDS is made available to subscribers.

       8.3    BRANDING. With respect to the HSDS, and the promotion thereof, I3S
and SEREN shall mutually establish the brand names, logos, labels, trademarks,
HSDS marks and other such identifying promotional characteristics pertaining to
the same throughout the term of this Agreement.

       8.4    RE-EVALUATION OF ECONOMIC TERMS. Thirty-six (36) months after the
Effective Date, and upon the expiration of each twenty-four (24) month period
thereafter, or in the event of any final regulatory or judicial proceedings,
changes or decisions affecting the HSDS at the HFC Network, the parties agree to
renegotiate the Revenue Allocation in good faith in accordance with current
market standards, such that the Revenue Allocation shall be increased or
decreased if either party is economically disadvantaged hereunder, or receiving
an inordinate proportion of the revenue associated with HSDS in relation to its
investment or contribution to the relationship established hereby.

         In addition, I3S agrees to decrease its percentage share of Revenue
by * for every * HSDS Subscribers that Seren achieves on an aggregate basis for
all of its HFC Networks, excluding the St. Cloud HFC Network. However, except as
provided for in this Section 8.4 above, in no event shall I3S receive less than
* Revenue Share as provided for herein.

       8.5    COMPED SERVICE. I3S understands and agrees that, upon advance
written notice to I3S, Seren shall have the ability to provide comped (i.e.
free) Internet access services to employees, primary and secondary schools,
libraries and local governmental facilities. No Revenue will be due I3S as a
result of such services being offered by Seren.

                                    ARTICLE 9
                          SPECIFIC SOFTWARE WARRANTIES

       9.1    OWNERSHIP; AUTHORITY. I3S represents and warrants that the
software utilized hereunder (collectively, the "Products") are free and clear of
all liens and encumbrances, and that it has full power, license and authority to
utilize the rights granted to it with respect to such Products without the
consent of any other person or that such consent has been obtained, and that to
the knowledge of I3S the Products utilized hereunder will not infringe or
violate any copyright, trade secret, trademark, patent or other intellectual
property rights of any third party.

       9.2    SOFTWARE COMPATIBILITY. I3S will accommodate any subscriber
browser (e.g. Netscape, Explorer) or operating systems (Windows, NT, MAC, Unix).

       9.3    SEREN'S Y2K REQUIREMENTS. All computer systems and applications,
and all embedded computer components and devices maintain full functionality,
performance, and future maintainability, accurately process date/time data
(including but not limited to, calculating, comparing, sorting, and sequencing)
from, into, between, and throughout the twentieth and twenty-first centuries. In
addition to all other contract requirements, I3S agrees

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that the services and/or equipment provided to Seren under this agreement are
Year 2000 compliant. I3S agrees that its operations will be capable of
continuing an uninterrupted flow of goods and services into and through the year
2000. I3S agrees that the computing software and hardware, supplies, material,
or equipment ("Equipment") purchased, rented, leased or acquired for use by
Seren is compliant with Seren's "Year 2000 Requirements," (defined below) and
said Equipment shall not be accepted in part or whole by Seren unless
specifically disclosed and agreed to by Seren in writing.

                                   ARTICLE 10
                                 INDEMNIFICATION

       10.1   INTELLECTUAL PROPERTY RIGHTS INDEMNIFICATION. I3S shall defend,
indemnify and hold harmless SEREN, its directors, officers, shareholders,
employees and agents and its successors and assigns, from and against any and
all claims, demands, actions, liabilities, losses, damages and expenses,
including, without limitation, settlement costs and reasonable attorneys' fees,
arising out of or relating to any actual or alleged infringement of any third
party's trade secrets, trademark, HSDS mark, copyright, patent or other
intellectual property rights (the "Intellectual Property Rights") in connection
with the use of said Intellectual Property Rights hereunder. I3S's obligation
pursuant to the immediately preceding sentence is subject to the following
conditions: (i) SEREN shall give I3S prompt written notice of all actions,
claims or threats against SEREN of infringement or violation of Intellectual
Property Rights; (ii) SEREN shall permit I3S to elect to assume complete control
of such claims at its sole discretion and expense; and (iii) SEREN shall
cooperate fully with I3S in defending against claims, including making known or
available to the indemnifying party, upon reimbursement of all costs associated
with provision or reproduction of, all records and document pertaining to
claims.

       10.2.  INDEMNIFICATION. Each party shall indemnify the other against all
liability, loss, damage, and expense resulting from injury to or death of any
person (including injury to or death of their employees) or loss of or damage to
tangible real or tangible personal property (including damage to their property)
or the environment, but only to the extent that such liability, loss, damage or
expense was proximately caused by its breach of this Agreement or by any
negligent act or omission, willful misconduct or violation of law on the part of
the party from whom indemnity is sought ("the Indemnitor"), its agents,
employees, subcontractors or assignees. Indemnitor shall have the right to
assume defense of the claim with counsel reasonably acceptable to Indemnitee.
Indemnitee shall be entitled to participate in the defense of the claim with its
own counsel at its sole expense.

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                                   ARTICLE 11
                        PROTECTION OF PROPRIETARY RIGHTS

       11.1   CONFIDENTIAL INFORMATION. Information to be held in confidence
shall be clearly marked "Proprietary" or "Confidential." Information which is
conveyed orally shall be deemed confidential only if prior to disclosure it is
indicated as being confidential and written confirmation identifying the
confidential or proprietary information is provided to the receiving party
within ten (10) business days after it was discussed orally.

       11.2   RESTRICTIONS. Each party shall use its reasonable best efforts to
maintain the confidentiality of such Confidential Information and not show or
otherwise disclose such Confidential Information to any third parties,
including, but not limited to, independent contractors and consultants, without
the prior written consent of the disclosing party. Each party shall use the
Confidential Information solely for purpose of performing its obligations under
this Agreement. Unless approved in advance by the non-disclosing party, except
for the existence of this Agreement, the terms and provisions of this Agreement
shall remain strictly confidential and shall not be disclosed to any third party
other than a party's attorneys, accountants and other professional advisers.

       11.3   AUTHORIZED DISCLOSURES. Notwithstanding the obligations described
in Section 11.2 above, neither party shall have any obligation to maintain the
confidentiality of any Confidential Information which: (i) is or becomes
publicly available by other than unauthorized disclosure by the receiving party;
(ii) is independently developed by the receiving party; or (iii) is received
from a third party who has lawfully obtained such Confidential Information
without a confidentiality restriction. If required by any court of competent
jurisdiction or other governmental authority, the receiving party may disclose
to such authority, data, information or material involving or pertaining to
Confidential Information to the extent required by such order, provided that the
receiving party shall first have used its best efforts to obtain a protective
order reasonably satisfactory to the disclosing party sufficient to maintain the
confidentiality of such data, information or materials.

       11.4   LIMITED ACCESS. Each party shall limit the use and access of
Confidential Information to such party's bona-fide employees or agents who have
a need to know such information for purposes of conducting the receiving party's
business. Each party shall notify all employees and agents who have access to
Confidential Information or to whom disclosure is made that the Confidential
Information is the confidential, proprietary property of the disclosing party
and shall instruct such employees and agents to maintain the Confidential
Information in confidence.

       11.5   CONTINUING OBLIGATIONS. Each party's obligations under this
Article 11 shall survive the termination of this Agreement for two (2) years
thereafter.

       11.6   CONFIDENTIALITY OF TERMS. Unless approved in advance by the
non-disclosing party, except for the existence of this Agreement, the terms and
provisions of this Agreement shall remain strictly confidential and shall not be
disclosed to any third party other than a party's attorneys, accountants and
other professional advisers.

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       11.7   SEREN SUBSCRIBERS. Without the prior written consent of
Seren, I3S will not disclose information about Seren customers who are being
offered HSDS or who have subscribed to HSDS. In addition, I3S will not market
any other services to Seren customers without giving Seren prior notification.
I3S shall not reveal the name or addresses of Seren customers to any third party
except as necessary to fulfill its obligation to provide the HSDS. I3S shall not
permit any third party to use the Seren customer names for any purpose unrelated
to this Agreement.

                                   ARTICLE 12
                              DEFAULT; TERMINATION

       12.1   DEFAULT. Upon the occurrence of any of the following events, a
party shall be deemed to be in default under this Agreement:

  (a) Material breach of any warranty or misrepresentation by the defaulting
party;

  (b) Material failure to perform the defaulting party's obligations hereunder,
including with respect to I3S its failure to maintain the HSDS standards set
forth in Section 7.1 hereof;

  (c) The defaulting party's ceasing to conduct business in the normal course,
insolvency, the making of a general assignment for the benefit of its creditors,
suffering or permitting the appointment of a receiver or similar officer for
its business or assets or availing itself of, or becoming subject to, any
proceeding under the United States Federal Bankruptcy Laws or any federal or
state statute relating to solvency or the protection of the rights of creditors;
or

  (d) Making of any warranty, representation, statement or response in
connection with this Agreement which was untrue in any material respect on the
date it was made by the defaulting party.

       12.2   REMEDIES. In the event the defaulting party fails to cure any
default set forth hereunder within thirty (30) days, except for defaults
pursuant to Section 12.1(c) which shall have a cure period of ninety (90) days,
after written notice of such default by the non-defaulting party specifying the
acts or omissions constituting the default with reference to the sections of
this Agreement which have allegedly been breached, the non-defaulting party may
terminate this Agreement without further obligation on the part of the
non-defaulting party, and pursue any claims at law or in equity against the
defaulting party.

       12.3   FAILURE TO EXERCISE REMEDY. The remedies set forth above are
cumulative, but the non-defaulting party is under no obligation to exercise any
such remedy. The exercise of, or failure to exercise, any such remedies shall
not prevent any future exercise of the same or any other remedies or release the
defaulting party from its obligations under this Agreement.

       12.4   EFFECT OF TERMINATION. Termination of this Agreement shall not
impair either party's then accrued rights, obligations, liabilities or remedies
hereunder.

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       12.5   TRANSITION UPON TERMINATION. Notwithstanding the termination
of this Agreement, I3S shall maintain its facilities and continue to provide the
HSDS to the HFC Networks for a reasonable period of time (not to exceed six (6)
months from the date of termination) until SEREN has made arrangements with
another Internet service provider, and I3S shall cooperate with SEREN in an
orderly and efficient transition of the Subscribers to any other Internet
service provider designated by SEREN.

                                   ARTICLE 13
                           NOTICE; PUBLIC DISCLOSURES

       13.1   NOTICE. All notices pursuant to this Agreement shall be in writing
and may be personally delivered or sent by overnight courier or by Certified or
Registered mail. All notices personally delivered shall be deemed delivered at
the time of such delivery. All notices sent by Certified or Registered mail
shall be deemed delivered five (5) days after deposited in the US mail. All
notices sent by overnight courier shall be deemed made one (1) business day
after delivery to such courier HSDS. Any party may designate a change of address
upon ten (10) days written notice.

                                       If to I(3)S, to:
                                       I(3)S, Inc.
                                       1440 Corporate Drive
                                       Irving Texas 75038
                                       Attn: Mr. Jim Price, CEO

                   with a copy to:
                                       I(3)S, Inc.
                                       1440 Corporate Drive
                                       Irving Texas 75038
                                       Attn: Matt Hutchins, President

                                       If to SEREN, to:
                                       SEREN Innovations, Inc.
                                       15 South 5th Street, Suite 500
                                       Minneapolis, MN 55402
                                       Attn: President

       13.2   PUBLIC DISCLOSURES. All media releases, public announcements, and
public disclosures by either party of its employees, agents or representatives
relating to this Agreement or the subject matter hereof, excluding any
announcement beyond the control of this disclosing party, will be approved by
the non-disclosing party in writing prior to release.

                                   ARTICLE 14
                               DISPUTE RESOLUTION

         In the event a dispute arise between SEREN and I3S, or the successors
or assigns of either of them, regarding this Master Agreement or any particular
HFC Network Agreement, the

                                       12
<PAGE>   13

aggrieved party shall promptly notify the other Party of its intent to invoke
this dispute resolution procedure after such dispute arises. If the Parties
shall have failed to resolve the dispute within ten (10) days after delivery of
such notice, each Party shall, within five (5) days thereafter nominate a senior
officer of its management to meet at any mutually agreed location to resolve the
dispute. Should the Parties be unable to resolve the dispute to their mutual
satisfaction within ten (10) days after such nomination, such dispute shall be
settled by arbitration.

         The Party desiring arbitration shall give notice to the other Party in
writing specifying the question or questions to be settled and at the same time
naming an arbitrator. The Party receiving such notice shall within ten (10) days
thereafter give to the other Party a like written notice giving the name of an
arbitrator chosen by it and specifying any additional matter on which an award
is desired. If the Party receiving notice of arbitration fails to name an
arbitrator within ten (10) days, then the second arbitrator shall be appointed
by the American Arbitration Association. Only Parties qualified as specialists
in the matter in controversy will be appointed as arbitrators. The third
arbitrator shall, within ten (10) days of the appointment of the second
arbitrator, be selected by the two arbitrators theretofore appointed. If
arbitrators shall have been appointed by the respective parties and shall have
failed to select the third arbitrator, within the time provided herein, the
third arbitrator shall upon application of either of the parties to the
arbitration, be appointed by the American Arbitration Association within ten
(10) days after receipt of a Party's application to appoint a third arbitrator.
The arbitrators shall proceed immediately to hear and determine the matter in
controversy. Each Party shall be entitled to produce witnesses and appear in
person and by counsel before said arbitrators, but the number of witnesses to be
heard, the length of argument, the time consumed in such hearing, and the
general conduct of the proceedings shall conform to the rules promulgated by the
American Arbitration Association. The arbitrators shall be limited to accepting
the position contended for by either I3S or Seren, without modification, in
making their award. The arbitrators shall be instructed that their awards must
be made within forty-five (45) days of the appointment of the third arbitrator,
subject to any reasonable delay due to unforeseen circumstances. The award of
the arbitrators shall be drawn up in writing and signed by the arbitrators, or a
majority of them, and shall be final and binding on the Parties, and the Parties
shall abide by the award and perform the terms and conditions thereof. The award
of the arbitrators shall be made retroactive to the date the first Party
notified the other Party of its intent to invoke the dispute resolution
procedure. Unless otherwise determined by the arbitrators, the fees and expenses
of the arbitrator named by I3S shall be paid by I3S, the fees and expenses of
the arbitrator named by Seren shall be paid by Seren and the fees and expenses
of the third arbitrator shall be paid in equal proportions by the Seren and I3S.
Save as herein otherwise expressly provided, the rules of the American
Arbitration Association shall apply; provided, however, that wherever and
whenever there is conflict between the provisions of this Article and the
provisions of the said rules, the provisions of this Article shall apply.

         Notwithstanding any other remedies, and in the event that either Party
brings legal action upon the other Party for failing to perform any of its
obligations or failing to act in accordance with the provisions of this
Agreement, the Party which prevails in such legal action shall be entitled to
recover all reasonable legal fees incurred with regard to the legal action from
the other Party.

                                       13
<PAGE>   14

         I3S is obligated to continue providing HSDS as provided for herein
during the pendency of any dispute.

                                   ARTICLE 15
                                  MISCELLANEOUS

       15.1   ENTIRE AGREEMENT. This Master Agreement, together with the
schedules, attachments and exhibits attached hereto or referred to herein,
constitutes the entire Agreement and understanding among the parties hereto with
respect to the provision of the HSDS at the HFC Networks and is the final
expression of their Agreement on that subject and no evidence of oral or other
written promises shall be binding. All other prior agreements or understandings
related to the subject hereof among the parties, whether written or oral, shall
be null and void and of no further force and effect upon the execution of this
Agreement. This Agreement shall be binding upon and inure to the benefit of the
parties hereto and their respective successors and permitted assigns.

       15.2   INCORPORATION BY REFERENCE. The schedules, exhibits and
attachments referred to herein or attached hereto are hereby incorporated in and
to this Agreement and made a part hereof by this reference.

       15.3   AMENDMENT; MODIFICATION. This Agreement may not be supplemented,
amended, modified or otherwise altered except by written instrument executed by
all the parties hereto and no course of dealing or trade usage among or
between the parties shall be effective to supplement, amend, modify or alter
this Agreement.

       15.4   WAIVER. The failure to enforce or to require the performance at
any time of any of the provisions of this Agreement herein shall in no way be
construed to be a waiver of such provisions, and shall not affect either the
validity of this Agreement, any part hereof or the right of any party thereafter
to enforce each and every provision in accordance with the terms of this
Agreement.

       15.5   GOVERNING LAW. This Agreement, and any claims, counterclaims and
cross suits, shall be governed by and construed in accordance with the local
laws of the state in which the defendant or non-enforcing party resides, without
regard to conflicts of law principles. Each party hereby irrevocably submits to
the jurisdiction of the state or federal courts of the state in which the
defendant or non-enforcing party resides for the resolution of disputes
hereunder.

       15.6   CONTINUITY OF CONTRACT. If any severable provision of this
Agreement is deemed invalid or unenforceable by any judgment of a court of
competent jurisdiction, the remainder of this Agreement shall not be affected by
such judgment, and this Agreement shall be carried out as nearly as possible
according to its original terms and intent, unless to do so would substantially
impair the underlying purposes of this Agreement.

       15.7   CAPTIONS. The captions appearing in this Agreement are included
solely for convenience of reference and shall not be construed or interpreted to
affect the meaning or interpretation of this Agreement.

                                       14
<PAGE>   15

       15.8   FORCE MAJEURE. Neither party shall be responsible for any failure
to comply with or for any delay in performance of the terms of this Agreement,
including, but not limited to, delays in delivery, where such failure or delay
is directly or indirectly caused by or results from events of force majeure
beyond the control of either party. These events shall include, but not be
limited to, fire, flood, earthquake, accident, civil disturbance, war, acts of
God, or acts or government.

       15.9   HIRING PROHIBITED. During the term of this Agreement and for a
period of one (1) year thereafter, neither party shall solicit for hire or hire
any employee of the other party who has performed SERVICES under this Agreement.

       15.10  PERFORMANCE REVIEW. In the event of any dispute or controversy
between the parties of any kind or nature, except in circumstances where
equitable relief is deemed necessary by either party in its sole discretion,
upon the written request of either party, each of the parties will appoint a
designated officer whose task it will be to meet for the purpose of resolving
such dispute or controversy or to negotiate for an adjustment to any provision
of this Agreement needed to resolve such dispute or controversy. Such officers
will discuss the dispute or controversy and negotiate in good faith in an effort
to resolve the dispute or controversy or renegotiate the applicable section or
provision of this Agreement without the necessity of any formal proceeding
relating thereto. No formal proceedings for the judicial or arbitrational
resolution of such dispute or controversy may be commenced until either or both
of the designated officers conclude in good faith that an amicable resolution
through continued negotiation of the matter at issue is not likely to occur.

       15.11  BINDING NATURE; ASSIGNMENT. This Agreement will be binding on the
parties hereto, and their respective successors and assigns. Upon prior written
notice to the other party, either party may assign its rights and delegate its
duties under this Agreement; provided however, that the assignee party must
unconditionally assume in writing, and agree to be bound by, the right, duties
and obligations of the assignor party under this Agreement.

       15.12  RELATIONSHIP OF THE PARTIES. Notwithstanding anything to the
contrary in this Agreement, under no circumstances will either party be deemed
to be in any relationship with the other party carrying with it fiduciary or
trust responsibilities. The parties do not intend for this Agreement or the
relationship established thereby to be considered the formation of a joint
venture or partnership between the parties for any purpose. I3S has the sole
right to supervise, manage, contract, direct, procure, perform or cause to be
performed the day-to-day work to be performed by I3S under this Agreement unless
otherwise expressly provided herein or agreed to by the parties in writing.

       15.13  COUNTERPARTS. This Agreement may be signed in counterparts with
the same effect as if the signature on each counterpart were upon the same
instrument.

       15.14  SEVERABILITY. The Parties agree that multiple HFC Networks may
become subject to this Agreement. Any default or termination (whether voluntary
or involuntary) by any party with respect to a particular HFC Network shall
operate as a default or termination only

                                       15
<PAGE>   16

with respect to the parties' responsibilities and obligations as they relate to
the specific HFC Network or HFC Networks, as the case may be. Unless otherwise
agreed to by the parties with respect to the particular default, a default shall
be construed, where possible, to exclude unaffected HFC Networks.

       15.15  COMPLIANCE WITH APPLICABLE LAWS. I3S represents and warrants that
the provision of the HSDS pursuant to this Agreement shall be in compliance with
all applicable federal and state laws, rules and regulations.

       IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the date first above written.

I(3)S, INC.                        SEREN INNOVATIONS, INC.

By: /s/ MATTHEW HUTCHINS           By:   /s/ GLYNIS HIRSCHBERGER
   --------------------------         --------------------------------
   Matthew Hutchins                Printed Name: Glynis Hirschberger
   President                                    ----------------------
                                   Title: President and CEO
                                         -----------------------------

Date:  6/22/99                     Date:    6/21/99
     ------------------------           ------------------------------

                                       16
<PAGE>   17

                                LIST OF EXHIBITS

 EXHIBIT A: Description of the High Speed Data Services Provided by I3S

 EXHIBIT B: HSDS Service Level Agreement

 EXHIBIT C: HFC Network List

                                       17
<PAGE>   18

                                    EXHIBIT A

             DESCRIPTION OF HIGH SPEED DATA SERVICES PROVIDED BY I3S

The I3S HSDS is a data network that provides transport and peering functions of
Internet Protocol (IP) data traffic, including, without limitation:

o  Broadband access networks at the HFC Network composed of one or more
   broadband access technologies including but not limited to coaxial or hybrid
   fiber coaxial (HFC) cable television distribution systems, twisted-pair
   copper-wire-based telephone distribution systems, twisted-pair
   copper-wire-based local area network distribution systems and
   fiber-optic-based local area network distribution systems;

o  Local loop networks that connects the broadband access networks on each HFC
   Network to the I3S regional points-of-presence (POPs) in each metropolitan
   area served by I3S;

o  Regional point-of-presence networks that connects the POPs to the i3s.net
   national IP backbone;

o  A national IP backbone consisting of broadband communication facilities for
   the transport of data among I3S POPs and public and private Exchange Points
   where data and Internet routing information will be exchanged with other
   networks peered with i3s.net as part of the global Internet;

o  A national Network Operations Center (NOC).

o  Certain computer services that include:

      o         Membership system for user authentication and authorities;
      o         Personalization services for customizing content to user
                preferences;
      o         Internet mail (SMTP and POP3);
      o         Internet newsgroups (NNTP) composed of approximately 25,000 or
                more newsgroups;
      o         Internet World Wide Web (HTTP) services;
      o         Internet chat (IRC and MIRC);
      o         Conferencing and collaboration bridges;
      o         Streaming multimedia services such as Microsoft's NetShow and
                Progressive Network's RealMedia;
      o         A branded suite of client software that include:
      o         Web browser;
      o         Mail reader;
      o         News reader;
      o         Chat client;

                                       1
<PAGE>   19
      o         Chat client;

      o         Conferencing and collaboration client;

      o         Appropriate plug-ins and ActiveX controls.

o  Certain customer HSDS functions that include:

      o         A National Customer Care Center;

      o         A telephone and network-based customer help desk;

      o         A Trouble Reporting facility;

      o         A customer billing system.

o  Certain multimedia-rich content that showcases the capabilities of HSDS that
   includes:

      o         Original content created by I3S;

      o         Aggregated content created by others but licensed by I3S and
                improved for uses in a HSDS System;

      o         Aggregated content created by others but licensed by I3S and
                used unimproved.

                                       2
<PAGE>   20
                                  REQUIREMENTS
                      RELATED TO BROADBAND ACCESS NETWORKS
             UTILIZING MULTIPLE BROADBAND ACCESS TECHNOLOGIES (mBAT)

SEREN'S RESPONSIBILITIES

         Provide, or cause to be provided, as mutually agreed between the
         parties, suitable physical-layer coaxial-cable, twisted-pair
         copper-wire, or fiber-optic distribution plant on each SEREN property
         that will meet or exceed I3S specifications;

         Maintain, or cause to be maintained, physical layer distribution plants
         built and owned by SEREN that are used for I3S's HSDS;

         Install, maintain and operate data delivery equipment for each HSDS HFC
         Network. Installation and maintenance will meet or exceed
         manufacturer's specifications and the requirements set forth in the
         Agreement. Through itself or its agents, SEREN will assist I3S with
         pre-installation engineering planning and HFC Network site survey
         questionnaires;

         Assume the cost of the acquisition of all data communication equipment
         necessary to provide HSDS and to provide termination and delivery of
         HSDS between the Subscriber and the I3S POP in each Market;

I3S RESPONSIBILITIES:

         Provide technical specifications for suitable physical-layer
         distribution plants for I3S's HSDS;

         Inspect and accept or reject, according to the mutually agreed
         specifications, physical-layer distribution plants proposed by SEREN as
         suitable for 13S's HSDS;

         Integrate all data delivery equipment for each HFC Network into the I3S
         Element Management System portion of its Network Management Platform
         using SNMP and/or RMON. I3S will monitor all data delivery equipment
         twenty-four hours per day, seven day per week (24x7);

         Without limitation on the foregoing or the attached SLA, both parties
         acknowledge that the end to end performance of HSDS is probabilistic
         and subject to anomalous short lived usage patterns by Subscribers
         which will affect both the utilization of the local loop circuits and
         the i3s.net national backbone from time to time;

         Configure and operate all data delivery equipment to efficiently
         integrate with the rest of the i3s.net network;

         Provide HSDS transport through the POP to Headend, except as noted
         herein.

                                       3
<PAGE>   21

                             ADDITIONAL REQUIREMENTS
                      RELATED TO BROADBAND ACCESS NETWORKS
                 UTILIZING CABLE TELEVISION DISTRIBUTION SYSTEMS

SEREN'S RESPONSIBILITIES (THESE RESPONSIBILITIES SPECIFICALLY APPLY TO THE
EXTENT HSDS IS TO BE PROVIDED BY I3S BY MEANS OF AN INTERCONNECTION TO SEREN'S
CATV DISTRIBUTION PLANT AT EACH HFC NETWORK. SEREN SHALL USE ALL COMMERCIALLY
REASONABLE EFFORTS TO PERFORM THESE RESPONSIBILITIES.):

    Cause CATV infrastructure to comply with FCC requirements;

    Upgrade, or cause to be upgraded, property CATV infrastructure to provide
    bi-directional cable delivery to all subscribers;

    Cause the upgraded bi-directional CATV infrastructure to exceed the minimal
    operational requirements of the I3S cable modem system, which are:

<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------------
           MINIMUM CABLE TELEVISION NETWORK                                VALUE
             REQUIREMENTS FOR i3s.net HSDS
----------------------------------------------------------------------------------------------------
<S>                                                      <C>
Amplitude variations inband
  Forward channel                                        5 dB total
  Return channel                                         5 dB total
----------------------------------------------------------------------------------------------------
Group delay variation inband
  Forward channel                                         60 nsec/MHz, 240 nsec total
  Return channel                                         200 nsec/MHz, 800 nsec total
----------------------------------------------------------------------------------------------------
Maximum tap to tap variation                             27 dB
----------------------------------------------------------------------------------------------------
Dynamic range on receiver                                -15 dBmV to +15 dBmV
----------------------------------------------------------------------------------------------------
Maximum return/upstream loss                             49 dB
----------------------------------------------------------------------------------------------------
Minimum carrier to noise                                 22 dB
----------------------------------------------------------------------------------------------------
Minimum carrier to interference                          25 dB
----------------------------------------------------------------------------------------------------
</TABLE>

Provide, or cause to be provided, four (4) six MHz (or as mutually agreed to by
the Parties from time to time) video channels within the CATV infrastructure
bandwidth on Internet served properties; two (2) in the spectrum from 54 MHz to
750 MHz and two (2) in the

                                       4
<PAGE>   22

    5MHz to 50 MHz spectrum; and reserve additional video channels, in the same
    spectrums for future expansion as Subscriber penetration at the HFC Network
    increases; and

    Designate, or cause to be designated, an engineering point of contact for
    each cable company operating the cable television distribution system for
    I3S Network Operations Center (NOC) to report problems or failures related
    to the cable television distribution system twenty-four hours per day, seven
    days per week (24x7).

I3S RESPONSIBILITIES:

        Use the cable modem system, and certain network management features that
        it provides, to monitor the availability and quality of SEREN's property
        network (its CATV plant) and the Equipment;

        Within (15) fifteen minutes of notice, report to SEREN's designated
        engineering point of contact any problems observed by the I3S NOC in the
        course of operating the cable modem system network management features;
        and

        Within (15) fifteen minutes of notice, report to SEREN's designated
        engineering point of contact any problems determined by Subscriber
        contact in the course of operating the Subscriber Help Desk.

        I3S to provide NOC connections and services to monitor end to end
        network connections.

                                       5
<PAGE>   23

                           LOCAL LOOP CHARACTERISTICS

SEREN'S RESPONSIBILITIES

     Provide, or cause to be provided, proper space, security and power for
     Local Loop termination and transmission equipment necessary to provide
     Internet delivery and other data services at each HFC Network.

     Order, provision, install and maintain local loop communications links
     between each HFC Network and I3S POP in each Market with a bandwidth as
     mutually agreed to by the Parties.

I3S RESPONSIBILITIES:

     Install, maintain and operate local loop termination and transmission
     equipment necessary for each property offering HSDS. Installation and
     maintenance will meet or exceed manufacturer's specifications and the
     requirements set forth in the Agreement. Through itself or its agents,
     SEREN will assist I3S with pre-installation engineering planning and site
     survey questionnaires;

     Integrate all local loop termination and transmission equipment for each
     HFC Network into the I3S Element Management System portion of its Network
     Management Platform using SNMP and/or RMON. I3S will monitor all local loop
     termination and transmission equipment twenty-four hours per day, seven day
     per week (24x7);

     Assume the cost of the acquisition of all local loop termination and
     transmission equipment necessary to provide HSDS and to provide termination
     and delivery of HSDS between the Property and the I3S POP in each Market;

     Without limitation on the foregoing or the attached SLA, both parties
     acknowledge that the end to end performance of HSDS is probabilistic and
     subject to anomalous short lived usage patterns by Subscribers which will
     affect both the utilization of the local loop circuits and the i3s.net
     national backbone from time to time; and

     Configure and operate all local loop termination and transmission equipment
     to efficiently integrate with the rest of the I3S.net network.

                                       6
<PAGE>   24

                                POINT OF PRESENCE
                    FEATURES AND ESTABLISHMENT REQUIREMENTS

I3S RESPONSIBILITIES:

     Acquire, install and maintain data communication equipment at each POP for
     the termination and transmission of HSDS from properties to the i3s.net
     national network backbone;

     I3S will determine the location of its main presence in each Market to be
     consistent with its own operational practices (which currently include
     co-locating within its carrier's central offices in each Market);

     Acquire, install, maintain and operate Internet peering relationships at
     public and private Internet Exchange Points (EP) with other Tier 1 Internet
     backbone networks throughout the United States;

     Acquire, install, maintain and operate computers and software to provide
     Network Management and provide Internet SERVICES for Subscribers. To
     provide these functions, I3S will employ a combination of
     locally-distributed-to-the-POP servers as well as globally centralized
     servers consistent with its overall network design and operational
     practices; and

     Order, provision, install, maintain and operate data transport/carriage
     pathways from each POP, EP and/or NOC with a bandwidth not less than 45
     mb/s (DS-3) interconnection. In addition, as the number of Subscribers on
     Market increases, scale the bandwidth so that each simultaneously active
     user averages approximately 1 mb/s ninety eight percent (98%) of the time,
     provided however, I3S is not guaranteeing bandwidth throughput from its POP
     to subscribers.

                                       7
<PAGE>   25

                           I3S INFORMATION OPERATIONS
             CONTENT PRODUCTION; SEREN/BROADBAND NOW!(TM) LAUNCH PAGE

I3S operates, and shall operate for the term of this Agreement, an information
content operation for creating original content or aggregating content created
by others and licensed to I3S for inclusion in the I3S body of content. This
material will consist of but not limited to informational, educational,
recreational, entertainment and business content. This body of content will be
offered to Subscribers of the HSDS product.

Without limitation on paragraph 1 above, I3S will create content as creative
and/or business opportunities present themselves. The I3S content will be
updated as I3S, using its editorial judgment, sees fit, but in no event less
frequently than good industry practice.

Certain portions of this content will be offered to all Subscribers free of
charge (Basic Content). Other portions of the content may be offered to
Subscribers on an optional fee basis for unlimited access to a fixed package of
content (Premium Content). Another certain portion of the content may be offered
to Subscribers on an optional fee basis for access to a specific time-limited
event (Pay-Per-View Content).

In addition to the fees charged customers for content, I3S may solicit and sell
national advertising and other revenue-producing transaction opportunities that
will appear on certain portions of the content.

All fees for premium content, pay-per-view content, national advertising and
revenue-producing transactions shall be determined solely by I3S.

The potential revenue set forth here for content shall not be subject to other
provisions in the Agreement (including attachments) regarding revenue sharing,
fees and pricing.

I3S, or its content partners, will design, produce and update, as necessary, all
content and be responsible for all such costs.

I3S shall initially design, produce and update, as necessary, a customized
launch page (the "Launch Page") for Subscribers, which can be used to market and
promote the HSDS, and, on I3S's standard time and materials rates (or as
otherwise agreed by the parties), SEREN's other SERVICES. In addition, the
Launch Page will include hyperlinks to SEREN's corporate web sites as directed
by SEREN. The Launch Page shall meet the technical, functional and appearance
requirements specified by I3S. I3S shall from time to time update the Launch
Page throughout the Term in accordance with the terms of this Agreement. I3S may
offer Subscribers Launch Pages that are personalized (by property) and that, in
addition to the features described above, may promote the I3S content offerings
and provide direct hyperlinks to the I3S content.

In no event, at any time during the term of this Agreement, shall I3S knowingly
permit or use any (i) content in the SEREN/Broadband Now! web site or within its
information content operations which contains obscene material, sexually
explicit adult programming, or indecent material as defined in Section 47
C.F.R.76.701(g); (ii) material in the SEREN Broadband

                                       8
<PAGE>   26

Now! web site soliciting or promoting unlawful conduct; or (iii)
programming in the SEREN/Broadband Now! web site that may or could have been
subject to the Telecommunications Act of 1996, Section 641, relating to the
scrambling of sexually explicit adult video HSDS programming.

CONTENT PUBLISHING PLATFORM

       o  I(3)S will provide SEREN access to its automated publishing system for
          the purposes of SEREN publishing localized content in each of its
          geographic markets into the SEREN/BroadbandNOW! information service.
       o  SEREN's local content will be contained within the brand and Internet
          domain of BroadbandNOW!
       o  SEREN will provide the editorial and advertising content and be
          responsible for the costs of its creation.
       o  SEREN will sell advertising that may be associated with the local
          content it creates and keep any resulting revenue.
       o  I(3)S will provide a Web-based and/or email-based interface for
          SEREN's personnel to enter editorial content into the I3S publishing
          system.
       o  I(3)S will provide a workflow process for SEREN to manage and approve
          the publication of editorial content.
       o  I(3)S will provide the use of its standard publishing templates for
          publishing SEREN's local content in the BroadbandNOW! pages.
          Development of specialized or non-standard publishing templates
          requested by SEREN will be at SEREN's expense.

I(3)S CONTENT PHILOSOPHY

       o  Internet access is always an "open" experience.
       o  Customers spend time on our network only when it offers a high degree
          of value.
       o  They use our content and services because they want to, not because
          they have to.
       o  We develop content and services that take advantage of the unique
          value of the broadband experience rather than trying to rebuild or
          replace those services our customers already use and enjoy.

                          CONTENT DEVELOPMENT STRATEGY

       o  Bring the best content and services onto our network.
       o  Focus on a new class of services that are broadband specific or that
          are greatly enhanced by broadband.
       o  Develop original content and a new interface designed specifically for
          this medium and this audience, delivering a coherent whole.

STRATEGY: THE BEST OF THE NET

       There are some "basics" users expect:

              1. Search

                                       9
<PAGE>   27

              2. News

              3. Weather

              4. Stock Quotes, etc.

       Rather than rebuilding these functions, we enhance the experience of
using them.

                        STRATEGY: A NEW CLASS OF SERVICES

       o  There is an emerging new category of services that are broadband only
          or that are greatly enhanced by broadband.

       o  High-bandwidth content and services that were only theorized before
          can be delivered now.

       o  I(3)S is investing in the infrastructure to bring these services
          on-network and to integrate them highly with the rest of our offering.

 Strategy:  Built for Broadband

       o  I(3)S has developed an original platform and leading edge interface
          designed for broadband that brings it all together.

       o  And developed a new class of content, built from the ground up
          specifically for our broadband audience.

 Timeline:  Version 2.0 - March 1999

       o  Sections expanded from four to seven, establishing a platform for more
          original and aggregated content
       o  Greatly expanded localization
       o  Broadcast.com integration
       o  Backup service
       o  Portal partner
       o  Expanded help and customer account management and services

                          TIMELINE: VERSION 3.0 - Q3/Q4

       o  CD-ROM library online
       o  Other Targets/Goals:

              1. Online Gaming
              2. Expanded audio and video library
              3. Web-based email

       o  With greater depth comes a higher degree of personalization

                                       10
<PAGE>   28

                     LOCALIZATION: LEVEL 1 -- NATIONAL VIEW

       o   Smaller markets get a national view with access to most or all
           services not specifically tailored to their local market

       o   This is where the competition stops!

       Localization: Level 2 -- Localized View

       o   In larger markets, all services are customized to the local area:

                 1.   Local news, weather, sports, links, etc.
                 2.   Localized libraries of aggregated video, audio, multimedia
                      content

                  LOCALIZATION: LEVEL 3 -- ORIGINAL DEVELOPMENT

       o   Markets with large populations, or markets of strategic importance
           also get:

                 1.   Original, exclusive, local content developed specifically
                      for broadband and specifically for the local market
                      through two methods:

                 2.   Local I3S teams develop content

                 3.   Local partners develop content exclusively for I(3)S

       o   Seren shall be entitled to create, author, promote and otherwise
           engage in the business related to local content offerings. Within the
           Seren/BBnow Homepage, Seren shall be allocated the local area as
           mutually agreed to be the Parties. Seren shall be entitled to solicit
           and insert advertising and other revenue producing transactions on
           local content for its own account in such allocated local area of the
           homepage. I3S agrees to facilitate the ability of Seren to create,
           update and insert both the local content and advertising originated
           by Seren.

       o   Seren and I3S will form an Editorial Board to ensure continuity
           between the Local and National content pages.

                                       11
<PAGE>   29

                        CUSTOMER ADVOCACY CENTER FEATURES

I3S RESPONSIBILITIES

       Provide a toll free number for:

              Initial technical support inquires
              Technical support for all HSDS issues
              Technical support for Subscriber CPE issues related to HSDS

       Answer toll free line consistent with the SEREN/I3S HSDS co-brand.

       Operate 24x7 customer care call center operation.

       Maintain sufficient customer services staff and call center capacity to
       connect to Subscribers within 1 minutes of call entering processing
       operation.

       Develop and publish escalation procedure for Customer HSDS
       Representatives related to network issues.

       Resolve technical issues within 24 hours if a phone call is required 95%
       of time, on a monthly basis.

       Develop and publish escalation procedures for SEREN to contact regarding
       technical issues related to the network.

                                       12
<PAGE>   30

                 SUBSCRIBERS' HARDWARE AND SOFTWARE INSTALLATION
                  SPECIFICATIONS AND INSTALLATION REQUIREMENTS

SEREN SHALL:

       Verify that potential Subscribers' personal computers meet the
       I3S-established minimum requirements for the supplied software and the
       HSDS;

       Make an appointment with each new Subscriber to meet the installation
       personnel for the installation of the HSDS in the Subscriber's unit;

       Collect the Subscriber information required to install, provision and
       complete the set up of Subscribers' HSDS. Seren and I3S will develop an
       appropriate paper-form-based system or automated system to facilitate
       this process;

       Provide, or cause to be provided, coaxial connection to the Subscriber's
       specified location;

       Verify, or cause to be verified, that the coaxial connection completed to
       the Subscriber's specified location exceeds the minimum operational
       requirements for the Seren-supplied CPE and the I3S HSD;

       Verify, or cause to be verified, and if necessary, promptly (but not more
       than a reasonable time frame set by SEREN) perform repairs such that all
       access network services function properly (and to not less than the
       standards pre-existing I3S HSDS operations) after I3S completes
       installation and throughout the provision of HSDS;

       Maintain a sufficient inventory of CPE for each Market and develop
       procedures to restock CPE as used in Subscriber installations;

       Issue and install the required CPE for the HSDS requested by the
       Subscriber;

       Meet the Subscriber at the Subscribers location at the scheduled time
       within the tolerances and limits as defined in the I3S HSDS Service Level
       Agreement;

       Install the required cable modems(s) and have HSDS operational in the
       Subscriber's unit within the number of days of a Subscriber's request set
       forth in Section 6.4 of the Agreement;

       Install any required network interface cards (NICs), TCP/IP protocols and
       Internet software suite in the Subscriber's personal computer;

       Offer the Subscriber a brief introduction to the HSDS to be performed at
       the time of installation. This introduction will include how to launch
       the HSDS, how to find the training material on the I3S.net Web site, how
       to find the Subscriber Support Section on the I3S.net Web site and how to
       call for technical assistance or support;

                                       13
<PAGE>   31

       Obtain signatures required to verify that each Subscriber installation
       was executed properly and to the satisfaction of the Subscriber; and

       Provide a copy of the installation transaction documentation verifying
       that the completed installation is ready for billing. This documentation
       will include the CPE delivery receipt, the ISP contract and the completed
       work order.

                                       14
<PAGE>   32

                                    EXHIBIT B
                          HSDS SERVICE LEVEL AGREEMENT

This HSDS Level Agreement is attached and made a part of the Master High Speed
Data Services Right of Access and Marketing Agreement by and between I3S, Inc.
and Seren Innovations, Inc. (the "Agreement"). I3S shall use all commercially
reasonable efforts to perform these responsibilities.

INTRODUCTION

This Exhibit entitled "HSDS Level Agreement" ("SLA") sets out operation
specifications and requirements for HSDS provided by I3S for the residents or
customers of applicable SEREN HFC Networks. The SLA shall encompass data
SERVICES originating and terminating within the I3S internetwork ("i3s.net").

The HSDS provided by I3S shall meet the operations specification and
requirements stated herein, which are generally stated in terms of events or
outcomes, rather than terms of specific hardware, software or procedural
requirements. For the purposes of the SLA, i3s.net shall relate to that portion
of the global Internet operated by I3S, originating within end users' customer
premises and terminating within I3S computers or transported and peered at a
public or private Internet Exchange Point.

For the purposes of the SLA, a "Trouble" or "Trouble Report" shall relate to
i3s.net or I3S provided SERVICES (or resold SERVICES) and the Equipment and
I3S-maintained facilities, but shall exclude customer error, defects in Customer
Premises Equipment ("CPE"), defects in customers' computers, defects in property
cable or wiring plants, defects in fiber optic distribution systems, defects in
cable television distribution systems and network problems experienced by
destination networks at or beyond Internet Exchange Points.

The terms and conditions of this SLA do not limit I3S's obligations set forth
elsewhere in the Agreement, but if there is a conflict with respect to HSDS
obligations between this SLA and the Agreement, this SLA shall control.

PERFORMANCE REQUIREMENTS

PERCENT CUSTOMER HSDS ORDER BEGINNING COMMITMENT DATES TIMELY MET

       Except for self-installs, I3S will provide final Remote Provisioning of
Modem within one hour of notification by Seren.

PERCENT CUSTOMER HSDS ORDER COMPLETION COMMITMENT DATES TIMELY MET

       This parameter is generally indicative of the timely completion of work
       on orders from customers for new HSDS or orders to make changes in their
       existing HSDS and the timely completion of those HSDS orders.

                                       1
<PAGE>   33

       The timely completion parameter is calculated by dividing the total
       Customer HSDS Orders completed on or before the date and clock hour
       promised to the customer that the HSDS order would be completed by the
       total number of HSDS orders initiated in each calendar month and
       multiplying by 100.

       I3S shall exhibit greater than 90% Customer HSDS Order Completion
       Commitment Dates Timely Met per month.

PERCENT OF NETWORK AVAILABILITY

       This parameter is generally indicative of the availability of the network
       to transport and peer customer data at an Internet Exchange Point, or, in
       the event that the customer data is to be fulfilled by computers within
       i3s.net, generally indicative of the availability of to transport data to
       the I3S servers and the availability of the servers.

       This parameter is calculated by dividing the number of seconds that the
       network is available for each customer by the total number of
       customer-seconds in each calendar month and multiplying by 100.

       Specifically excluded from the Network Availability calculation shall be
       regularly scheduled maintenance windows upon 72 hours advance
       notification by I3S, or ad hoc maintenance windows scheduled and
       announced 24 hours in advance in the i3s.net Customer Support Web Site.

       Specifically excluded from the Network Availability calculation shall be
       periods of time where the access distribution plant (operated by SEREN or
       its designated third party operator) exceed the operational standards set
       by I3S for each type of Broadband access technology.

       I3S shall exhibit greater than 99.8% Network Availability per month.

       I3S to provide latency no greater than 120MS.

       Order, provision, install, maintain and operate data transport/carriage
       pathways from each POP, EP and/or NOC with a bandwidth not less than 45
       mb/s (DS-3) interconnection. In addition, as the number of Subscribers on
       Market increases, scale the bandwidth so that each simultaneously active
       user averages approximately 1 mb/s ninety eight percent (98%) of the
       time, provided however, I3S is not guaranteeing bandwidth throughput from
       its POP to subscribers.

PERCENT TIER 2 CUSTOMER CALLS ANSWERED WITHIN 45 SECONDS BY I3S PERSONNEL

       This parameter is based upon the number of customers calls answered
       within 15 seconds by a human operator or by an ACD queue greeting during
       the hours of operation of the I3S National Customer Care Center and
       thereafter to be answered by a human customer representative within 30
       seconds. At a minimum, the I3S National Customer Care Center

                                       2
<PAGE>   34

       shall operate from 8:00 a.m. to 5:00 p.m. Central Time, Monday through
       Friday exclusive of holidays.

       This parameter is calculated by dividing the number of calls answered
       with 45 seconds by the total number of Customer Care Center calls
       answered in each calendar month and multiplying by 100.

       I3S shall exhibit greater than 90% of Customer Calls Answered within 45
       Seconds per month.

PERCENT OF TROUBLE REPORTS RESOLVED TIMELY

       This parameter is related to the number of Trouble Reports resolved
       within the following windows:

       o     For Trouble Reports received by I3S at the I3S National Customer
       Care Center prior to 2:00 p.m. Central Time, Monday through Friday,
       excepting holidays, will be cleared by the end of the next business day.

       o     For Trouble Reports received by I3S at the I3S National Customer
       Care Center after 2:00 p.m. Central Time, Monday through Friday,
       excepting holidays, will be cleared by noon of the second business day
       thereafter.

       This parameter is calculated by dividing the total trouble reports
       cleared on or before the date and clock hour promised to the customer the
       total number of Trouble Tickets cleared in each calendar month and
       multiplying by 100.

       I3S shall exhibit greater than 90% Trouble Reports Cleared Timely per
       month, according to the terms of this section for trouble that can be
       resolved by I3S alone.

       I3S shall exhibit greater than 90% Customer Repair Commitment Met per
       month.

REPORTS

       I3S shall provide to SEREN reports within twenty (20) business days of
       the end of each calendar month, the reports listed below in this section,
       each of which may be provided separately or provided on a consolidated
       basis:

       A report depicting total subscribers, gross new customers and gross
       customers terminated separated by product tier and property.

       New HSDS orders, Trouble Reports opened and closed or cleared as
       appropriate separated by date and property.

                                       3
<PAGE>   35

       Aggregate I3S National Customer Care Center data depicting the
       distribution of call waiting time in general and the percent calls
       answered and calls abandoned respectively.

HOLIDAYS

       New Years Day
       Memorial Day
       Independence Day
       Labor Day
       Thanksgiving
       Day after Thanksgiving
       Christmas

                                       4
<PAGE>   36

                                    EXHIBIT C

                               HFC NETWORK LISTING

1.     Seren's HFC Network serving St. Cloud, Minnesota and related service
       areas.

2.     Seren's HFC Network serving Contra Costa County, California.

                                       1<PAGE>   1

                                                                   EXHIBIT 10.19

                        CONFIDENTIAL TREATMENT REQUESTED

                               PURCHASE AGREEMENT

THIS AGREEMENT is made as of July 23, 1999 by and between ADAPTIVE BROADBAND
CORPORATION ("Adaptive Broadband"), a Delaware corporation with a principal
office at 1143 Borregas Avenue, Sunnyvale, CA 94089, and I(3)S, INC. ("Buyer"),
a Texas corporation with a principal office at 1440 Corporate Drive, Irving, TX
75038.

                                    RECITALS:

A.   Adaptive Broadband is a developer, manufacturer and supplier of wireless
     telecommunications equipment.

B.   Buyer desires to provide wireless communications network services in
     the U.S. ("Territory") for residential non-commercial multiple dwelling
     unit ("MDU") markets ("Markets").

C.   Adaptive Broadband and Buyer each desire for Adaptive Broadband to sell and
     Buyer to purchase such products for use in connection with those services,
     all on the terms and conditions set forth in this Agreement.

                                   PROVISIONS:

NOW, THEREFORE, in consideration of the mutual representations, warranties and
covenants contained in this Agreement, the parties agree as follows:

1.   SCOPE OF AGREEMENT.

     a.   Equipment and Services. Buyer agrees to buy and Adaptive Broadband
          agrees to sell to Buyer the products described in Exhibit A attached
          to this Agreement ("Products") and the services described in Exhibit B
          attached to this Agreement ("Services").

     b.   Purchase Orders. Buyer may issue purchase orders for any Products or
          Services ("Purchase Orders") to Adaptive Broadband via mail or
          facsimile, in form and content acceptable to Adaptive Broadband.
          Purchase orders will be considered accepted by Adaptive Broadband when
          expressly acknowledged and accepted by Adaptive Broadband in writing
          within the term of this Agreement. Subject to the exception in the
          following sentence, the terms and conditions of this Agreement will
          govern the relationship between the parties and each Purchase Order.
          Therefore, each Purchase Order will automatically be deemed to include
          all the terms and provisions of this Agreement, and any contractual
          terms and conditions contained in a Purchase Order or its reverse side
          will not apply and will be null and void, except to the extent that
          Adaptive Broadband expressly and specifically accepts such other or
          additional terms and conditions in writing. Buyer shall provide to
          Adaptive Broadband firm purchase orders 120 days in advance of Buyer's
          intended delivery, which purchase orders will become effective only
          upon written acknowledgment and acceptance by Adaptive Broadband.
          Buyer may make one change in quantity under a given purchase order,
          +/- 20% of the dollar amount under that order, by written notice to
          Adaptive Broadband at least 30 days before the delivery date contained
          in Adaptive Broadband's order acceptance.

2.   PRICING AND PAYMENT.

     a.   Pricing. All prices are FOB Adaptive Broadband's relevant U.S.
          facility or its supplier's dock, as may be specified by Adaptive
          Broadband, and are valid for the term of this Agreement. The first
          quoted prices for Products and Services are set forth in Exhibit A and
          Exhibit B, respectively. For so

                                     Page 1

<PAGE>   2

          long as Buyer is in material compliance with its material obligations
          under this Agreement, the prices set forth in Exhibit A for Products
          will be at least as favorable as those offered by Adaptive Broadband
          to customers purchasing Products in substantially like quantities on
          substantially like delivery schedules.

     b.   Payment. All payments by Buyer will be made to Adaptive Broadband
          pursuant to the payment terms and conditions set forth in Adaptive
          Broadband's Standard Terms and Conditions of Sale, attached to this
          Agreement as Exhibit C.

3.   QUANTITY COMMITMENTS.

     a.   Firm Commitment. Buyer agrees to purchase a minimum of * AB-Access
          units (in any combination of access points and subscriber units)
          during the term of this Agreement in accordance with Exhibit A,
          provided (i) the field trial verification and Acceptance Test
          Procedure described in Section 8 and both Exhibit E and Exhibit F are
          completed and materially satisfied in accordance with their terms,
          (ii) Adaptive Broadband is in material compliance with the material
          provisions of this Agreement, and (iii) Adaptive Broadband receives
          FCC certification for the Products.

     b.   Initial Purchase Order. Buyer will issue a Purchase Order within 30
          days of the effective date of this Agreement for one access point and
          three subscriber units for use in the field trial verification of the
          Product outlined in Exhibit E in accordance with the Acceptance Test
          Procedure and parameters set forth in Exhibit F.

     c.   Forecasts. Each quarter (as specified by Adaptive Broadband from time
          to time), Buyer will provide Adaptive Broadband with a non-binding
          rolling quarterly forecast covering the period of 12 calendar months
          beginning with the quarter in which that forecast is provided. Each
          forecast will specify the number of units of Products (separating
          access points and subscriber units) which Buyer anticipates it will
          purchase during each quarter of that 12-month period.

4.   SOFTWARE LICENSE.

     a.   License. Adaptive Broadband grants to Buyer a royalty-free, perpetual,
          and non-exclusive license to use the Software (defined below) within
          the Territory and Market in connection with the Products and Buyer's
          wireless communications network services. Buyer's right to use the
          Software shall be subject to the terms and conditions set out in
          Exhibit D.

     b.   Sub-License. Adaptive Broadband grants to Buyer a royalty-free,
          perpetual, and non-exclusive license to sub-license the Software to
          Buyer's customers and other parties contracting with Buyer for the
          delivery, of broadband wireless data access, each of which utilizes
          Products in the Territory and Market in connection with Buyer's
          wireless communications network services. When granting to customers
          the right to use Software, Buyer shall incorporate in such
          sub-license terms that offer no less degree of protection to Adaptive
          Broadband's (or its licensor's) interest in the Software as those set
          out in Exhibit D.

     c.   "Software". As used in this Agreement, "Software" means any program in
          machine readable code (howsoever provided to Buyer), and intended to
          be loaded into the memory of a Product's processor unit(s) which
          provides operating instructions and user-related application
          instructions (as well as associated documentation used to describe,
          maintain and use such programs), incorporated in any of the Products
          by Adaptive Broadband or supplied to Buyer by Adaptive Broadband for
          use on or in connection with any of the Products; however, Software
          shall not mean any source code.

                                     Page 2
<PAGE>   3

     d.   Third Party Software. The Products and Software include software which
          is licensed by third parties to Adaptive Broadband ("Third-Party
          Software"). Adaptive Broadband will provide Buyer with a copy of the
          requirements and restrictions of all licenses which apply to existing
          and then future Third-Party Software. Each party ("Licensee") agrees
          to defend, indemnify and hold the other ("Other Party") harmless from
          and against any loss, damages, costs, fees (including reasonable
          attorneys' fees) and expenses awarded against or incurred by the Other
          Party as a result of the Licensee's failure to comply with the
          requirements and restrictions of Third-Party Software licenses and
          sub-licenses applicable to the Licensee pursuant to the terms of the
          relevant license or sublicense, or as a result of the Licensee's
          failure to comply with the reasonable requests of the Other Party in
          the Other Party's efforts to comply with the Third-Party Software
          license or sub-license requirements and restrictions imposed upon it.

5.   SOFTWARE MAINTENANCE.

     a.   Notification. Throughout the term of this Agreement and the first 12
          months thereafter, each party will promptly notify the other of any
          defect or error it becomes aware of in any Product or Software or
          documentation.

     b.   Maintenance. For the 12 months immediately following shipment of
          Product and Software ("Software Maintenance Period"), Adaptive
          Broadband will provide to Buyer, free of charge, an element management
          system and all Software bug fixes which are released by Adaptive
          Broadband and made available to the general public solely as a "bug
          fix." These will be provided to Buyer for Buyer to load into
          previously shipped Products and Adaptive Broadband will provide them
          with subsequently shipped Products. Those bug fixes will be governed
          by the provisions of this agreement as "Software."

     c.   Limitations. Adaptive Broadband has no obligation to correct any
          defect or error in the Software to the extent it arises from any
          improper or unauthorized use or operation of the Software by the Buyer
          or its employees or agents, or the adaptation, modification or
          alteration of any part of the Software without Adaptive Broadband's
          prior consent, or any failure by Buyer to install any corrected
          version or any update or improvement of the Software or documentation
          supplied by Adaptive Broadband.

     d.   Third Party Software. Adaptive Broadband will, during the relevant
          warranty period, be responsible for maintenance and support of any
          Third-Party Software which Buyer may use in conjunction with the
          Software or Products. Thereafter, Adaptive Broadband will quote the
          price and details for extended warranty coverage upon request.

     e.   Updates. Buyer acknowledges that updates may involve the use of new
          versions of Third-Party Software or operating systems. Adaptive
          Broadband shall not be responsible for the cost of any new Third-Party
          Software required by Buyer or any related charges if Buyer decides to
          utilize an update provided by Adaptive Broadband.

     f.   Replacements. Buyer shall upon written request by Adaptive Broadband
          return to Adaptive Broadband the replaced version of any updated
          Software and documentation.

     g.   Hardware Updates. Subject to Exhibit A's provisions regarding
          competitive technology, updated Product hardware may become available
          from time to time and will be supplied to Buyer upon Adaptive
          Broadband's terms.

                                     Page 3

<PAGE>   4

6.   GENERAL TERMS AND CONDITIONS.

     Adaptive Broadband's Standard Terms and Conditions of Sale is attached to
     this Agreement as Exhibit C and is hereby incorporated by reference into
     this Agreement and made a part hereof.

7.   CHANGES, MODIFICATIONS AND ENHANCEMENTS.

     Adaptive Broadband will provide the Product enhancements as and how
     described in Exhibit E attached to this Agreement and, with those
     enhancements, the Products will be covered under the product warranty set
     forth in Exhibit C. Throughout the term of this Agreement, Adaptive
     Broadband will maintain the availability of those enhancements in its
     then current generally available Product (except as otherwise agreed to by
     Adaptive Broadband and Buyer in writing), subject only to materials and
     technology availability. Except as otherwise specifically provided in
     Exhibit E, any changes, modifications, or enhancements of the Products
     requested by Buyer which affects either software or hardware modules
     contained therein will be quoted by Adaptive Broadband separately; no
     change order will be implemented until the parties mutually agree in
     writing to the price for this change. Any changes, modifications, or
     enhancements of the Products made by Adaptive Broadband at its own
     initiative and made a part of its then standard Product will become part
     of the Product without additional charge to Buyer. Any changes,
     modifications, or enhancements of the Products made by Adaptive Broadband
     at its own initiative which are not made a part of its then Standard
     Product but are instead offered as an optional feature or upgrade will be
     available to Buyer at an additional agreed upon price.

8.   ACCEPTANCE TESTING AND FIELD TRIALS.

     a.   Exhibit E contains the details of the field trials procedures and
          parameters applicable to the Products purchased by Buyer, which tests
          will be performed at a Buyer location within the continental United
          States. Exhibit F contains the details of the acceptance test
          procedures, specifications, and parameters applicable to Products
          purchased by Buyer. Adaptive Broadband will give Buyer reasonable
          notice of the date of the test and Buyer will make available all
          staff, materials and facilities which Adaptive Broadband reasonably
          requires for the performance of the test. Buyer may not reject any
          Product which has successfully completed all acceptance tests in
          accordance with Exhibit F and field trials in accordance with Exhibit
          E. If an acceptance test is not successfully completed in accordance
          with Exhibit F, and/or if a field trial is not successfully completed
          in accordance with Exhibit E, then Adaptive Broadband and Buyer will
          mutually agree within the ensuing 10 days on a later date when the
          relevant test shall be repeated and the provisions of the relevant
          exhibit will apply to each repeat test conducted. The date on which
          the field trials are successfully completed in accordance with Exhibit
          E is referred to as the "Trial Completion Date."

     b.   All acceptance tests will be at Buyer's location in Irving, Texas. Any
          inspections or testing beyond that those set forth in Exhibit F
          (including any secondary or follow-up inspections or tests) or which
          otherwise exceed, in scope or duration, those normally provided by
          Adaptive Broadband in like circumstances, will be subject to approval
          by Adaptive Broadband, be at additional cost to Buyer, may be deemed
          by Adaptive Broadband to be an event of force majeure for Adaptive
          Broadband's benefit to the extent they affect Adaptive Broadband's
          and/or Buyer's other obligations hereunder, and Adaptive Broadband may
          impose cancellation or rescheduling charges accordingly.

     c.   Buyer agrees that it will initiate the acceptance tests sets forth in
          Exhibit F within 10 business days after delivery of Adaptive
          Broadband's designated final version of the Product enhancements with
          appropriate network management support, and Buyer will complete those
          acceptance tests within 5 business days thereafter. Buyer agrees that
          it will initiate the field trials set forth in Exhibit E within 10
          business days after the successful completion of the Exhibit F
          acceptance tests, and Buyer will complete those field trials within 90
          days thereafter. Those tests and trials which are not completed

                                     Page 4
<PAGE>   5

          successfully will be repeated as necessary in accordance with the
          provisions of this Agreement including without limitation Section
          8(a). Subject to the foregoing, Buyer will use commercially reasonable
          efforts to promptly, successfully and satisfactorily complete all
          tests and trials, and any and all repeat tests and trials.

9.   DOCUMENTATION.

     Adaptive Broadband will provide to Buyer its standard documentation in
     Adaptive Broadband's standard forms, formats, and quantities based on the
     size and scope of the relevant order. Additional copies, and any changes in
     this documentation required by customization of the Products or software
     changes made in response to Buyer requests will be at an additional charge.

10.  PRE-APPROVAL SHIPMENTS.

     Buyer may desire to have Adaptive Broadband build and ship Products for
     actual use in the Territory and Market without Adaptive Broadband having
     FCC Product certification and/or without Buyer having a license required
     by it as a Product operator, whether from the FCC or other or additional
     licensing and approval authorities.

     a.   In order to induce Adaptive Broadband to do build and ship Products
          for actual use in the Territory and Market without Adaptive Broadband
          having FCC Product certification, Buyer agrees as follows: (i) Buyer
          will assist Adaptive Broadband in any labeling requirements, (ii) If
          the Product does not get all requisite approvals, licensing and
          certification on the first round and without additional input from
          Adaptive Broadband, Buyer will honor Adaptive Broadband's reasonable
          requests regarding the scope of the use of those Products until that
          requisite approval, licensing and certification is secured, (iii) If
          Adaptive Broadband deems it necessary or appropriate by reason of the
          approval and/or licensing process for Products to be returned to
          Adaptive Broadband, whether for modification or replacement, then all
          costs and expenses associated with shipping to Adaptive Broadband and
          back to Buyer, as well as all costs and expenses associated with that
          modification or replacement, will be borne by Buyer, (iv) These and
          any other terms for the premature building and shipping of Products
          are binding upon Buyer but are subject to the prior approval,
          requirements, and business judgment of Adaptive Broadband in each
          instance.

     b.   In order to induce Adaptive Broadband to do build and ship Products
          for actual use in the Territory and Market without Buyer having a
          license required by it as a Product operator, whether from the FCC or
          other or additional licensing and approval authorities, Buyer agrees
          as follows: (i) If Adaptive Broadband deems it necessary or
          appropriate by reason of the approval and/or licensing process for
          Products to be returned to Adaptive Broadband, whether for
          modification or replacement, then all costs and expenses associated
          with shipping to Adaptive Broadband and back to Buyer, as well as all
          costs and expenses associated with that modification or replacement,
          will be borne by Buyer, (ii) If Adaptive Broadband deems it necessary
          or appropriate for Adaptive Broadband to send someone on-site to
          facilitate the licensing and/or approval process, then all costs and
          expenses associate therewith will be borne by Buyer, (iii) Buyer will
          defend, indemnify and hold Adaptive Broadband harmless from and
          against any and all judgments, fines, amounts paid in settlement,
          damages, claims, costs, expenses (including attorneys' fees) and
          liabilities incurred and arising out of or related to the premature
          shipping and use of Products.

11.  CONFIDENTIALITY.

     a.   Definition of Confidential Information: Each party ("Disclosing
          Party") may, either orally, in written form, or otherwise disclose to
          the other party ("Recipient") or the Recipient may otherwise obtain
          the Disclosing Party's confidential information ("Confidential
          Information"). If any of the following

                                     Page 5
<PAGE>   6

          apply to any information, such information shall not be considered as
          Confidential Information: (i) it is or becomes available to the public
          through no wrongful act of the Recipient, (ii) it is already in the
          possession of the Recipient as evidenced by documentation in the
          Recipient's possession, and not subject to any agreement of confidence
          between the parties, (iii) it is received from a third party without
          any restriction known to the Recipient for the benefit of the
          Disclosing Party, or (iv) it is independently developed by the
          Recipient without regard to that Confidential Information disclosed by
          the Disclosing Party.

     b.   Use and Care of Confidential Information: Confidential Information
          disclosed or obtained hereunder during the term of this Agreement
          shall only be used by the Recipient only in the performance of its
          obligations or exercise of its rights under this Agreement, and it
          shall not be disclosed by the Recipient for a period of three (3)
          years from the date of disclosure, except to those employees,
          affiliates, advisors, and consultants of the Recipient who have a need
          to know and an obligation to treat Confidential Information in
          accordance with the provisions of this Agreement. The Recipient may
          disclose the Disclosing Party's Confidential Information pursuant to a
          requirement of a duly empowered government agency or a court of
          competent jurisdiction after due notice and an adequate opportunity to
          intervene is given to the Disclosing Party unless such notice is
          legally prohibited. Notwithstanding the expiration or early
          termination or cancellation of this Agreement, the obligations under
          this Section 12(b) shall survive until they expire in accordance with
          their terms.

     c.   Return of Confidential Information: Upon receipt of a written request
          from the Disclosing Party, the Recipient shall, at the Disclosing
          Party's direction, either return to the Disclosing Party or destroy
          all of the Disclosing Party's Confidential Information and so
          certify in writing.

12.  REPRESENTATIONS, WARRANTIES, AND COVENANTS.

     a.   By Adaptive Broadband. Adaptive Broadband represents and warrants to
          Buyer, and covenants that:

          i.   Adaptive Broadband has all corporate power and authority to enter
               into this Agreement and consummate the transactions contemplated
               hereby; and

          ii.  Adaptive Broadband has all the rights necessary to license the
               rights and to supply the Products to Buyer as provided in this
               Agreement.

          iii. Adaptive Broadband covenants that, for the two year period
               beginning the Trial Completion Date and during that two year
               period for so long as Buyer is and remains in material compliance
               with the material provisions of this Agreement, Adaptive
               Broadband will not sell "AB-Access Product With Data Envelope
               Interface Enhancements" (defined below) with the Functionalities
               (defined below) enabled to either: (A) any company which competes
               with Buyer by providing broadband wireless data access to MDUs
               and which Adaptive Broadband Knows, at the time it accepts the
               relevant purchase order, intends for those Products to be used in
               connection with broadband wireless data access services in MDUs
               in the United States; or (B) any company which Adaptive
               Broadband Knows, at the time it accepts the relevant purchase
               order, will re-sell those Products to companies described in
               subsection 12(a)(iii)(A) immediately above.

               Notwithstanding the foregoing in this Section 12(a)(iii), that
               covenant shall not apply to the sale of AB-Access Product With
               Data Envelope Interface Enhancements with the Functionalities
               enabled to either: (X) any telecommunications service provider
               which at the time it seeks to purchase AB-Access Product With
               Data Envelope Interface Enhancements Products provides
               telecommunications services other than Product services, or (Y)
               any other company not specifically included within the class of
               companies covered by Section 12(a)(iii)(A) or (B).

               As used in this Section 12(a)(iii), Adaptive Broadband "Knows" of
               a fact only if one of its corporate officers has timely evidence
               of the fact, without any duty to investigate. "AB-Access

                                     Page 6
<PAGE>   7

               Product with Data Envelope Interface Enhancements" means a
               Product configured with the following functionalities
               ("Functionalities"):

               For subscriber unit Products:

               o    Pass-through forwarding of all upstream traffic

               o    Isolation of layer 2 data streams for upstream traffic

               For access point Products:

               o    Pass-thru upstream forwarding of all upstream traffic

               o    Layer two learning bridge functionality applied to all
                    downstream traffic

               o    Layer two learning bridge implementation using the
                    multiplexing of a single 1483 bridge mapping multiple ATM
                    PVCs among all learned addresses contained in the layer two
                    bridge table.

          iv.  Adaptive Broadband shall not utilize, in any manner whatsoever
               the corporate names or any trademark or trade name or copyright
               rights belonging to Buyer in connection with any equipment or
               service without the prior written approval of Buyer. This
               requirement of consent will survive the expiration or early
               termination of this Agreement.

          v.   Except as otherwise specifically provided in this Agreement, all
               approvals, permits, and authorizations from all applicable
               parties which are necessary for the performance by Adaptive
               Broadband of its obligations under this Agreement, and in
               furtherance of its purposes set forth in the recitals above, will
               be timely obtained and maintained by Adaptive Broadband at its
               own expense.

          vi.  Adaptive Broadband is free to make this Agreement and the making
               hereof and/or performance hereunder by it or any of its officers,
               directors, employees, contractors, consultants, and agents will
               not violate the legal and/or equitable rights or interests of
               any third party.

     b.   By Buyer. Buyer represents and warrants to Adaptive Broadband and
          covenants that:

          i.   Buyer has all corporate power and authority to enter into this
               Agreement and consummate the transactions contemplated hereby;

          ii.  Buyer shall not utilize, in any manner whatsoever the corporate
               names or any trademark or trade name or copyright rights
               belonging to Adaptive Broadband or other Product manufacturers in
               connection with any equipment or service without the prior
               written approval of Adaptive Broadband or the relevant
               manufacturer. This requirement of consent will survive the
               expiration or early termination of this Agreement. Buyer will
               not contest the validity of any of Adaptive Broadband's or other
               Product manufacturer's patents, trademarks, trade names or
               copyrights used in connection with Products; and

          iii. All approvals, permits, and authorizations from all applicable
               parties which are necessary for the performance by Buyer of its
               obligations under this Agreement, and in furtherance of its
               purposes set forth in the recitals above, will be timely obtained
               and maintained by Buyer at its own expense.

          iv.  Buyer is free to make this Agreement and the making hereof and/or
               performance hereunder by it or any of its officers, directors,
               employees, contractors, consultants, and agents will not violate
               the legal and/or equitable rights or interests of any third
               party.

13.  TERM AND TERMINATION.

     a.   Term. This Agreement will be effective as of the date first written
          above and will continue for the period ending sixty months after the
          Trial Completion Date, subject to earlier termination in accordance
          with this Agreement.

                                     Page 7
<PAGE>   8

     b.   Termination. Adaptive Broadband and Buyer each may by written notice
          to the other terminate this Agreement:

          i.   If a receiver is appointed for either party or its property:

          ii.  If either party becomes insolvent or unable to pay its debts as
               they mature in the ordinary course of business or makes an
               assignment for the benefit of its creditors:

          iii. If any proceedings are commenced by or for either party under
               bankruptcy, insolvency, or debtor's relief law, and those
               proceedings will not be vacated or set aside or stayed within
               ninety (90) days from the date of the commencement thereof:

          iv.  If either party is sequestered by any government authority:

          v.   If either party is liquidated, dissolved, or sells all or
               substantially all of its assets:

          vi.  If either party defaults in the performance of any material term
               or condition of this Agreement and that default continues
               unremedied to the non-defaulting party's satisfaction for a
               period of thirty (30) days after notice of default; provided any
               deviation from the terms of this Agreement which is required in
               order to be in compliance with the applicable laws, rules, or
               regulations of any government or subdivision thereof will not be
               considered a default hereunder:

     c.   Upon Expiration or Termination. Upon expiration or early termination
          of this Agreement for any reason, and notwithstanding that expiration
          or termination:

          i.   All provisions of this Agreement will survive with respect to
               each order accepted by Adaptive Broadband prior to the effective
               date of the expiration or termination until each party's
               obligations with respect to that order is either satisfied or
               waived:

          ii.  Termination of this Agreement shall be without prejudice to the
               rights and remedies of the party which may have accrued to
               either party as at the date of termination.

          iii. Notwithstanding the expiration or early termination of this
               Agreement, Section 11 ("Term and Termination") and the provisions
               of Exhibits C ("Terms and Conditions"), D ("Software License and
               Sub-Licensing"), and F ("Acceptance Testing") as they apply to
               any outstanding Purchase Orders shall remain in full force and
               effect and Adaptive Broadband shall still make available in
               accordance with the terms hereof Services to which Buyer is
               otherwise entitled in respect of Products supplied to Buyer prior
               to the date of termination.

          iv.  Notwithstanding the expiration or early termination of this
               Agreement, Section 12 ("Confidential Information") will survive
               for a period of 3 years after the date of disclosure.

          v.   Buyer will within 30 days after expiration or termination return
               to Adaptive Broadband in (at Buyer's sole cost and expense) (or
               at Adaptive Broadband's request eradicate or destroy): all
               literature, manuals and materials supplied to it by Adaptive
               Broadband and which are in Buyer's possession; all equipment
               provided to it by Adaptive Broadband and which Buyer did not
               purchase, in the condition in which it was sent by Adaptive
               Broadband; all tangible and intangible embodiments of Adaptive
               Broadband intellectual property, including software (except that
               which is in Products purchased by Buyer); all Information covered
               under Section 3.3; and any other items which Adaptive Broadband
               may reasonably request.

14.  MISCELLANEOUS.

     a.  Sole Agreement; Amendment; Waivers. This Agreement (together with its
         Exhibits and their attachments which are hereby incorporated into this
         Agreement by reference and made a part hereof) contains the entire
         understanding between Adaptive Broadband and Buyer with respect to its
         subject matter and supersedes all prior discussions, agreements and
         understandings between them with respect to that subject matter. All
         amendments hereto and all agreements between the parties supplemental
         to this Agreement must be in writing and signed by the parties hereto.
         The waiver by either party of a breach or violation of any provision of
         this Agreement must be in writing and will not operate or be construed
         as a waiver of any subsequent breach or violation.

                                     Page 8

<PAGE>   9

     b.   Independent Contractor. Each party acknowledges and agrees that this
          Agreement establishes an independent contractor relationship and each
          disclaims the existence of any employer/employee relationship or
          partnership or joint venture relationship between them. Neither party
          has authority to act for, represent, or bind the other and neither
          will take or fail to take any action inconsistent with this
          paragraph.

     c.   Liability and Indemnification. (i) Subject to the provisions of
          Sections 5, 7, and 12 of Exhibit C, each party ("Indemnifying Party")
          agrees to indemnify and hold the other party and its successors and
          assigns ("Indemnified Party") harmless from and against any and all
          judgments, fines, amounts paid in settlement, damages, claims, costs,
          expenses (including reasonable attorneys' fees) and liabilities
          actually incurred and arising out of or related to the Indemnifying
          Party's breach or threatened breach of this Agreement or any act or
          omission by any of the Indemnifying Party and its agents, employees,
          successors and assigns. (ii) The extent of Adaptive Broadband's
          liabilities to Buyer are solely and exclusively set forth in
          sections 5, 7, and 12 of Exhibit C. (iii) Neither Adaptive Broadband
          nor Buyer will be liable under this Agreement for any consequential
          damage including loss of clientele, loss of business, loss of data, or
          loss of profits. Neither party will be entitled to an indemnity for
          goodwill or other compensation upon termination of this Agreement at
          any time for any reason.

     d.   Buyer Affiliates. Notwithstanding the provisions of Section 14(d), if
          (i) Buyer is or becomes a party to a definitive written agreement
          with a third party for the delivery of broadband wireless data access
          and that third party can use Products in connection with that
          agreement and the delivery of that access, and (ii) Adaptive Broadband
          and that third party enter into a separate definitive written
          agreement for that third party's purchase of Products for that planned
          use, then each Product purchased by that third party under that
          separate Adaptive Broadband agreement will be credited towards the
          satisfaction of Buyer's quantity purchase obligations under this
          Agreement.

     e.   Severability. If any provision of this Agreement is determined by a
          court of competent jurisdiction to be unenforceable or illegal, then
          it will be deemed removed from the other provisions of this Agreement
          which will remain in effect.

     f.   Headings. Headings in this Agreement are included for convenience only
          and themselves have no force or effect.

     g.   Publicity. Neither party shall issue any press release or make any
          public announcement relating to this Agreement or its subject matter
          without the prior written approval of the other; provided that either
          party may make any public disclosure it believes in good faith is
          required by applicable law or any listing or trading agreement
          concerning its publicly-traded securities (in which case the
          disclosing party will use its best efforts to advise the other party
          prior to making the disclosure).

     h.   Order of Precedence. In the event of conflict between any of the
          provisions of this Agreement, the terms set forth above shall govern
          over Adaptive Broadband's Standard Terms and Conditions.

     i.   Governing Law and Related Matters. Any dispute or controversy between
          the parties regarding or arising out of this Agreement, an Exhibit or
          a purchase order which a party wants to resolve in litigation shall be
          brought by that party as follows:

          i.   If the plaintiff is Adaptive Broadband, then (i) it shall
               adjudicate its claim, and Buyer shall adjudicate any related
               cross-claims and counter-claims, in Dallas County, Texas, the
               jurisdiction, venue, and personal jurisdiction to which, for such
               claim or claims, the parties irrevocably consent; and (ii) for
               those claims, cross-claims and counter-claims, this Agreement,
               the Exhibits

                                     Page 9
<PAGE>   10

               and related purchase orders shall be construed in accordance with
               and governed by the internal laws of the State of Texas without
               reference to conflict of laws principles.

          ii.  If the plaintiff is Buyer, then (i) it shall adjudicate its
               claim, and Adaptive Broadband shall adjudicate any related
               cross-claims and counter-claims, in Santa Clara County,
               California, the jurisdiction, venue, and personal jurisdiction to
               which, for such claim or claims, the parties irrevocably consent;
               and (ii) for those claims, cross-claims and counter-claims, this
               Agreement, the Exhibits and related purchase orders shall be
               construed in accordance with and governed by the internal laws of
               the State of California without reference to conflict of laws
               principles.

          Buyer will observe and comply with all applicable governmental laws,
          rules and regulations. Buyer will promptly indemnify Adaptive
          Broadband for all damages, fines, and related expenses (including
          attorneys' fees) resulting from or arising out of Buyer's violation
          of any such law, rule or regulation or breach of this paragraph.

     j.   Notices. Except as otherwise provided in this Agreement, all notices,
          requests, and other communications under this Agreement will be in
          writing and sent by registered post or facsimile addressed to:

            If to Adaptive Broadband, to:              If to Buyer, to:

               Adaptive Broadband Corporation            I(3)S, Inc.
               1143 Borregas Avenue                      1400 Corporate Drive
               Sunnyvale, CA 94089                       Irving, TX 75038
               Attn: Sr. VP Broadband Systems            Attn: President
               Fax: (408) 732-4244                       Fax: (972) 650-7972

            With a copy to:                            With a copy to:

               Adaptive Broadband Corporation            I(3)S, Inc.
               1143 Borregas Avenue                      1440 Corporate Drive
               Sunnyvale, CA 94089                       Irving, TX 75038
               Attn: General Counsel                     Attn: General Counsel
               Fax: (408)732-4244                        Fax: (972) 650-7972

          Any notice sent by fax shall be deemed to be delivered the next
          working day following confirmed transmission, and any notice sent by
          post shall be deemed to be delivered five working days following the
          date of posting. Either party may change the address under this
          section by giving the other party proper notice.

              [The rest of this page is intentionally left blank.]

                                    Page 10
<PAGE>   11

IN WITNESS WHEREOF, Adaptive Broadband and Buyer each executed and deliver this
Agreement as of the date first written above.

I(3)S, INC.                                  ADAPTIVE BROADBAND CORPORATION

/s/ J. R. PRICE                              /s/ FRED LAWRENCE
------------------------------               ------------------------------
Signature                                    Signature

J. R. Price                                  Fred Lawrence
------------------------------               ------------------------------
Print Name                                   Print Name

CEO/CHAIRMAN                                 CHAIRMAN/CEO
------------------------------               ------------------------------
Title                                        Title

7/23/99                                      7/23/99
------------------------------               ------------------------------
Date                                         Date

                                             Legal Approval:
                                                            --------------------
                                                    Date:
                                                         -----------------------

                                             Finance Approval:
                                                              ------------------
                                                    Date:
                                                         -----------------------

                                TABLE OF EXHIBITS

                    Exhibit A - Products, Pricing, and Commitments

                    Exhibit B - Services and Related Pricing

                    Exhibit C - Adaptive Broadband's Standard Terms and
                                   Conditions of Sale

                    Exhibit D - Software License and Sub-License

                    Exhibit E - Enhancements and Field Trial Verification

                    Exhibit F - Acceptance Test, Procedures and Parameters

                                    Page 11
<PAGE>   12

                                    EXHIBIT A

                       PRODUCTS, PRICING, AND COMMITMENTS

PRODUCTS:    AB-Access UNII point to multi-point radio system (access points and
             subscriber units).
             AB-Access UNII point-to-point radio system (access points and
             subscriber units).

<TABLE>
<CAPTION>
PRICING AND COMMITMENTS:                                   Unit price
------------------------                              --------------------
                                                      subscriber    access
     Time frame               Quantity Commitment*       units      points
     ----------               --------------------    ----------    ------

<S>                           <C>                     <C>           <C>
     0-36 months after              * units                *           *
     Trial Completion Date

     0-60 months after            additional * units       *           *
     Trial Completion Date
</TABLE>

     *Buyer may purchase any combination of Product subscriber units and access
     points so long as in the aggregate it has purchased at least that number of
     total units required of it by the end of the relevant period.

     *Buyer may purchase and Adaptive Broadband will ship up to * units (in any
     combination of subscriber units and access points) through March 31, 2000.
     Buyer may purchase and Adaptive Broadband will ship additional units during
     that time period only upon Adaptive Broadband's prior consent. Subject to
     Buyer's * -unit and cumulative * -unit quantity obligations, there is no
     restriction on the number of units Buyer may purchase after March 31.
     2000."

1.   Notwithstanding anything to the contrary:

     (a)  If Buyer fails to satisfy its *-unit purchase obligation by the end of
          the relevant 36-month period, then with respect to its purchase
          deficiency from * units, Buyer shall pay to Adaptive Broadband a
          non-refundable amount equal to * of the agreed upon purchase price of
          the units it was obligated to but failed to purchase.

     (b)  If buyer fails to satisfy its * -unit purchase obligation by the end
          of the relevant 60-month period, then with respect to its purchase
          deficiency from * . Buyer shall pay to Adaptive Broadband a
          non-refundable amount equal to the difference between (i) * of the
          agreed upon purchase price of the units it was obligated to but failed
          to purchase by the end of that 60-month period, less (ii) the amount
          Buyer paid (if any) pursuant to Section 1(a) of this Exhibit A.

     (c)  If Buyer terminates or cancels this Agreement for any reason prior to
          purchasing * units, then with respect to its purchase deficiency from
          * . Buyer shall pay to Adaptive Broadband a non-refundable amount
          equal to * of the agreed upon purchase price of the units it was
          obligated to but failed to purchase.

     Buyer shall pay these obligations net 30 days after the end of that 36th
     month, net 30 days after the end of that 60th month, and net 30 days after
     that cancellation or termination date, as appropriate.

2.   In any subsequent Product purchase agreement(s) entered into between
     Adaptive Broadband and Buyer, Adaptive Broadband will give Buyer credit for
     the Products purchased by it under this Agreement in

                                    Page 12
<PAGE>   13

     determining the quantity discounts applicable to Buyer for Products
     purchased by it under that other agreement(s).

3.   Throughout the term of this Agreement, Adaptive Broadband agrees to
     maintain current Product technology which is competitive in the wireless
     broadband data access markets as measured on a bit-per-Hz basis,
     dollars-per-bit basis, and the general commercial availability of general
     features and functions in the wireless broadband data access markets. To
     define and satisfy that obligation, every six months throughout the term
     of this Agreement Adaptive Broadband and Buyer shall meet to review Buyer's
     upcoming Product technology preferences and Adaptive Broadband's Product
     development plans.

     If Buyer requests that Adaptive Broadband develop a general Product feature
     or function that is generally commercially available in the wireless
     broadband data access markets, then Adaptive Broadband will adjust its
     Product development schedule accordingly. If Adaptive Broadband at its own
     initiative develops a Product feature or function that is not so generally
     commercially available, then it will be available to Buyer at an
     additional agreed upon price.

                                     Page 13

<PAGE>   14

                                    EXHIBIT B

                          SERVICES AND RELATED PRICING

ENGINEERING SERVICES AND PRICING:

          Adaptive Broadband will provide up to * man-days of engineering and
          integration services to I(3)S, free of charge, during the field trial
          and acceptance test phases contemplated by this Agreement and Exhibit
          E. Thereafter, Adaptive Broadband will provide engineering and
          integration services at the rate of */day/man, plus materials and
          travel, lodging and subsistence expenses.

NON-ENGINEERING, INSTALLATION SUPPORT SERVICES:

          *  /day/man plus materials and travel, lodging and subsistence
             expenses.

                                     Page 14

<PAGE>   15

                                    EXHIBIT C

           ADAPTIVE BROADBAND'S STANDARD TERMS AND CONDITIONS OF SALE

The following are the terms and conditions under which Adaptive Broadband
Corporation ("ADAP") sells products, except as otherwise agreed to by ADAP in
writing:

1.   PRICES AND TAXES. The prices will be those set forth in ADAP's quotation or
     bid valid at the time of order. If a quotation has expired, ADAP reserves
     the right to extend the validity of the quotation or issue a new quotation
     at its discretion. Prices are F.O.B. shipping point (North American orders)
     / EX-WORKS (Incoterms, 1990) ADAP's relevant shipping facility
     (International orders), in U.S. dollars and are exclusive of all taxes,
     tariffs, duties and fees. In addition to all charges and fees due under any
     agreement or order between ADAP and Buyer, Buyer is solely responsible for
     and agrees to pay amounts equal to any taxes, tariffs, duties and fees
     (however designated) and any interest, fines and penalties (collectively,
     "Tax") resulting from or arising out of that agreement or order, exclusive
     of taxes based on ADAP's net income. Without limiting the generality of the
     foregoing, Buyer is solely responsible for and agrees to pay, either
     through the relevant product invoice or a separately issued invoice, all
     sales taxes resulting from or arising out of that agreement or order
     unless, within 30 days after shipment, ADAP receives export documentation
     satisfactory to ADAP evidencing the export of the relevant products out of
     the United States. If a Buyer within the United States wishes to have the
     agreement or order treated as sales tax exempt, ADAP must receive a resale
     or exemption certificate satisfactory to ADAP prior to shipment. Buyer will
     pay on ADAP's behalf any Tax levied upon ADAP or reimburse ADAP for any
     such Tax paid by ADAP. This Section will apply during and after termination
     of any agreement between the parties.

2.   ORDERS. No order submitted by Buyer will be deemed accepted by ADAP unless
     and until confirmed in writing by ADAP's authorized representative. No
     order which has been accepted by ADAP may be canceled by the Buyer except
     with the agreement in writing of ADAP and on terms that the Buyer
     will indemnify ADAP in full against all loss (including loss of profit),
     costs (including the cost of all labor and materials used), damages,
     charges and expenses incurred by ADAP as a result of cancellation
     including, at a minimum, the terms set forth in Section 10 below.

3.   PAYMENT. All payments by Buyer will be made in U.S. dollars in the U.S.
     pursuant to one of the following terms, without offset:

     Option 1: Confirmed. Irrevocable Letter of Credit acceptable to ADAP and
     payable in U.S. dollars at sight upon presentation of documents confirming
     shipment (i.e. Invoice, Packing List, Air Waybill) through any major
     United States state or national bank. Validity must be at least 120 days
     for shipment and 150 days for negotiation of documents: partial shipments
     must be allowed: the Letter of Credit value must state F.O.B. shipping
     point (North American orders) or EX-WORKS (Incoterms, 1990) ADAP's relevant
     shipping facility (International orders). Estimated freight and handling
     charges can be provided upon request. All banking charges are to Buyer's
     account.

     Option 2: 25% down-payment in U.S. dollars at the time of order with the
     balance due two weeks prior to shipment. Wire transfer information: Bank of
     America, 1850 Gateway Blvd., Concord, CA 93420, ABA# 121000358, Acct Name
     Adaptive Broadband Corporation, Acct Number 1233727981. Reference Invoice #
     and PO # and Contract #. By Order Of [Buyer's Name]: or such other wire
     transfer information as ADAP may indicate.

     Option 3: If Buyer continually satisfies ADAP's credit approval process and
     requirements and if ADAP provides Buyer with prior written approval of
     credit terms, then net 3O days after the relevant invoice date.

     If ADAP agrees in writing to Option 3 above or if ADAP agrees in writing to
     different or additional payment terms, then:

     a.   If during the period of performance of an order the financial
          condition of the Buyer is determined by ADAP not to justify the terms
          of payment specified, ADAP may demand that payment be made in
          accordance with one of the two options above.

     b.   ADAP reserves the right to make deliveries in installments, all
          installments to be separately invoiced and paid for by Buyer when due
          per invoice without regard to other scheduled deliveries. If shipments
          are delayed by the Buyer for any reason, payment will become due from
          the date on which ADAP is prepared to make shipment and storage will
          be at Buyer's risk and expense.

     c.   In the event of default in payment by Buyer: (i) ADAP may suspend
          performance of its obligations; (ii) Buyer agrees to pay ADAP's
          standard late charges plus interest on the delinquent payment from the
          due date thereof until such payment and all interest thereon is
          received at the rate of 1 1/2% per month, but not in excess of the
          lawful maximum (which charges and interest are not in lieu of any
          other right ADAP may have for Buyer's breach); and (iii) in the event
          of litigation or collection activity arising out of Buyer's
          non-payment, Buyer will promptly pay the reasonable costs and
          expenses incurred by ADAP, including attorney's fees.

4.   DELIVERY, SECURITY INTEREST, DELAYS. Delivery will be F.O.B. shipping
     point (North American orders)/ EX-WORKS (Incoterms, 1990) ADAP's relevant
     shipping facility (International orders). Freight and handling charges are
     to be either remitted in advance or collected under a confirmed,
     irrevocable Letter of Credit as outlined above. All shipments are subject
     to availability and

                                    Page 15
<PAGE>   16
     all references to dates are references to delivery F.O.B. shipping point
     (North American orders) / EX-WORKS (Incoterms l99O) ADAP's relevant
     shipping facility (International orders). Any dates for delivery quoted by
     ADAP or provided in an accepted order are approximations only and ADAP will
     not liable for delay in shipment for any reason. Title to product transfers
     and Buyer assumes all risk of loss upon delivery of product by ADAP to the
     initial carrier. Insurance will be provided by ADAP upon request and
     collected with freight and handling charges. In the absence of instructions
     to the contrary, ADAP on behalf of Buyer, will select the carrier but will
     not be deemed thereby to assume any liability in connection with the
     shipment nor will the carrier be construed to be an agent of ADAP. Claims
     for loss or damage to products in transit must be made to the carrier and
     not to ADAP. Buyer will be responsible for all storage, nagging, drayage
     and other charges to and at Buyer's site. Buyer hereby grants ADAP a
     security interest in the products and all cash and non-cash proceeds
     thereof as security for all of Buyer's obligations hereunder. Upon request
     by ADAP, Buyer will promptly execute any instrument required to perfect
     such security interest, provided that in any event ADAP is hereby appointed
     Buyer's attorney-in-fact to do all acts which ADAP deems reasonably
     necessary or desirable to perfect and continue to perfect such security
     interest and to protect the collateral. ADAP will not be liable for any
     damages or penalty for delay in delivery or for failure to give notice of
     delay when such delay is due to the elements, acts of God, delays in
     transportation, delay in delivery by ADAP's vendors or any other causes
     beyond the reasonable control of ADAP. The delivery schedule will be
     extended by a period of time equal to the time lost because of such delay.

5. INTELLECTUAL PROPERTY.

     If notified promptly in writing of any action (and all prior claims
     relating thereto) brought against Buyer alleging that Buyer's use or other
     disposition of product infringes a United States patent or copyright or
     trade secret, ADAP will defend such action at its expense and will pay the
     costs and damages awarded against Buyer in such action, provided that ADAP
     will have sole control of and authority with respect to the defense of any
     such action and all negotiations for is settlement or compromise. If a
     final injunction is obtained in such action against Buyer's use of the
     product or if in ADAP's opinion the product is likely to become the subject
     of claim or infringement, ADAP will, at its option and at its expense:
     procure for Buyer the right to continue using the product: or replace or
     modify the same so that they become non-infringing: or accept return of the
     product and refund or credit the amount of the original net purchase price,
     less a reasonable charge for depreciation and damage. ADAP will not have
     any liability to Buyer if the alleged infringement is based upon: (a) use
     or sale of the product in combination with other products or devices which
     are not made by ADAP; (b) use of the product in practicing any process: or
     (c) the furnishing to Buyer of any information, service or other
     assistance. No costs nor expenses will be incurred for the account of ADAP
     without the prior written consent of ADAP. In no event will ADAP's total
     liability to Buyer under or as a result of compliance with the provisions
     of this clause exceed the sum paid to ADAP by Buyer for the allegedly
     infringing product. The foregoing states the entire liability of ADAP with
     respect to alleged infringement of patents and copyrights by the product or
     any part thereof or by its operation. This Section states the entire
     liability of ADAP for any infringement of patent, copyright, trademark,
     trade secret, or other intellectual property rights.

     If notified promptly in writing of any action (and all prior claims
     relating thereto) brought against ADAP alleging that ADAP's use of or
     compliance with Buyer's designs, specifications, or instructions infringes
     a United States patent or copyright or trade secret. Buyer will defend such
     action at its expense and will pay the costs and damages awarded against
     ADAP in such action, provided that Buyer will have sole control of and
     authority with respect to the defense of any such action and all
     negotiations for its settlement or compromise. No costs nor expenses will
     be incurred for the account of Buyer without the prior written consent of
     Buyer. The foregoing states the entire liability of Buyer with respect to
     alleged infringement of patents and copyrights and trade secrets by the
     product or any part thereof or by its operation by reason of ADAP's use of
     or compliance with Buyer's designs, specifications or instructions.

6.   PRODUCT CHANGES. ADAP reserves the right, without prior approval from but
     with notice to Buyer, to make changes to products or their specifications
     (a) which do not materially adversely affect the performance of the product
     or reduce performance below any contract specification: (b) when required
     for purposes of safety: (c) to meet product specifications, or (d) when
     required to conform with any applicable statutory or regulatory
     requirements. ADAP reserves the right to make product improvements without
     incurring any obligation or liability to make the same changes in products
     previously manufactured or purchased. ADAP also reserves the right to
     modify the availability of models in its product lines based on market
     conditions, component availability, and other business considerations: and
     to require that Buyer implement and utilize software upgrades as a
     condition of maintenance contracts and warranty.

7.   WARRANTY

     PRODUCT MANUFACTURED BY ADAP:

     a.   Products manufactured by ADAP are warranted against defects in
          material and workmanship for a period of one (1) year from date of
          delivery as evidenced by ADAP's packing slip or other transportation
          receipt.

     b.   ADAP's sole responsibility under this warranty will be to either
          repair or replace, at its option, any component which fails during the
          applicable warranty period because of a defect in material or
          workmanship, provided Buyer has promptly reported same to ADAP in
          writing. All replaced products and parts will become ADAP's
          property.

     c.   ADAP will honor the warranty at the repair facility designated by
          ADAP. It is Buyer's responsibility to return, at its expense, the
          allegedly defective product to ADAP. Buyer must obtain a Return
          Material Authorization (RMA) number and shipping instructions from
          ADAP prior to returning any product under warranty. Transportation
          charges for the return of the product to Buyer will be paid by ADAP
          within the United States. For all other locations, the warranty
          excludes all costs of shipping,

                                    Page 16
<PAGE>   17

          customs clearance and other related charges. If ADAP determines in
          good faith that the product is not defective within the terms of this
          warranty, Buyer will pay ADAP all costs of handling, transportation
          and repairs at the then prevailing repair rates.

     d.   All the above warranties are contingent upon proper use of the
          product. These warranties will not apply (i) if adjustment, repair, or
          product or parts replacement is required because of accident, unusual
          physical, electrical or electromagnetic stress, neglect, misuse,
          failure of electric power, environmental controls, transportation,
          failure to maintained properly or otherwise in accordance with ADAP
          specifications, or abuses other than ordinary use, (ii) if the
          product has been modified by Buyer or has been repaired or altered
          outside ADAP's repair facility unless ADAP specifically authorizes
          such repairs or alterations in each instance; or (iii) where ADAP
          serial numbers, warranty data or quality assurance decals have been
          removed or altered.

     e.   No person, including any dealer, agent or representative of ADAP is
          authorized to assume for ADAP any other liability on its behalf except
          as set forth herein. If any payment is due ADAP for services performed
          hereunder, it will be subject to the same payment terms as the
          original purchase.

     PRODUCTS MANUFACTURED BY OTHERS:

     For products not manufactured by ADAP, the original manufacturer's or
     licensor's warranty will be assigned to Buyer to the extent permitted by
     the manufacturer or licensor and is in lieu of any other warranty,
     expressed or implied. For warranty information on a specific product, a
     written request should be made to ADAP.

     ALL PRODUCTS:

     THE FOREGOING WARRANTIES AND REMEDIES ARE EXCLUSIVE AND ARE IN LIEU OF ALL
     OTHER EXPRESS OR IMPLIED WARRANTIES, OBLIGATIONS, AND LIABILITIES ON THE
     PART OF ADAP. EXCEPT FOR THE EXPRESS WARRANTIES STATED HEREIN, ADAP
     DISCLAIMS ALL WARRANTIES ON PRODUCTS FURNISHED HEREUNDER. INCLUDING,
     WITHOUT LIMITATION, ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     FOR A PARTICULAR PURPOSE. ADAP WILL HAVE NO RESPONSIBILITY FOR ANY
     PARTICULAR APPLICATION MADE OF ANY EQUIPMENT. Any description of equipment,
     whether in writing or made orally by ADAP or its agents, specification
     sheets, models, bulletins, drawings, or similar materials used in
     connection with Buyer's order are for the sole purpose of identifying the
     equipment and will not be construed as an express warranty. Any
     suggestions by ADAP or its agents regarding use, application or
     suitability of the equipment will not be construed as an express
     warranty. No warranties may be implied from any course of dealing
     or usage of trade. Buyer agrees that the exclusion of all warranties,
     other than those expressly provided herein, is reasonable.

8.   ACCEPTANCE OF PRODUCTS. Unqualified acceptance of products will occur
     upon delivery, unless ADAP is notified in writing within ten days from
     Buyer's receipt that the products do not meet ADAP's specifications or
     that Buyer is making a claim for shortages or other errors in delivery.
     Failure to give such timely notice constitutes a waiver of all such
     claims by Buyer. ADAP's sole obligation for any non-conforming products
     will be limited to repair or replacement, at ADAP's option, pursuant to
     the provisions of the foregoing warranty clause.

9.   INSTALLATION. In the event ADAP agrees with Buyer to install or perform
     maintenance on any product(s) to be supplied. Buyer will pay ADAP'S then
     current standard charges for such installation or maintenance.

10.  CANCELLATION AND RESCHEDULE CHARGES. In the event Buyer defaults, ADAP may
     decline to make further shipments and/or may terminate Buyer's order
     without affecting ADAP's rights and remedies including, but not limited
     to, any right to cancellation charges and quantity price adjustments. If
     ADAP continues to make shipments after Buyer's default, ADAP's action
     will not constitute a waiver nor affect ADAPs legal remedies. In the
     event Buyer (a) cancels any order or portion thereof with the requisite
     ADAP consent; or (b) fails to meet any obligation hereunder, causing
     cancellation or rescheduling of any order or portion thereof; or (c)
     requests a rescheduling of scheduled product and such request is accepted
     by ADAP. Buyer agrees to pay ADAP cancellation/reschedule charges as a
     percentage of the list price of the canceled/rescheduled product, said
     charges having been agreed upon not as a penalty, but as a result of the
     difficulty of computing actual damages. Such cancellation/rescheduling
     charges may be set by ADAP in its business judgment in each instance. Buyer
     may not cancel or reschedule any order or portion thereof after shipment.

11.  EXPORT. Regardless of any disclosure made by Buyer to ADAP of an ultimate
     destination of the product(s). Buyer will not export, either directly or
     indirectly, any product(s) or non-ADAP equipment incorporating such
     product(s) without first obtaining a license from the U.S. Department
     of Commerce or any other agency or department of the United States
     Government, as required. Buyer will use its best efforts to insure that
     none of the products will reach any country where U.S. laws would forbid
     ADAP to market or distribute the products.

12.  DISCLAIMER AND LIMITATION OF LIABILITY.

     A.   ADAP'S TOTAL LIABILITY IS LIMITED TO THE NET PRICE OF THE PRODUCTS
          SOLD HEREUNDER, EXCLUDING ANY CHARGES STATED SEPARATELY FROM THE
          PRODUCT PRICE ON THE INVOICE. BUYER'S SOLE REMEDY FOR LIABILITY OF ANY
          KIND, INCLUDING NEGLIGENCE, WITH RESPECT TO THE PRODUCTS, SOFTWARE,
          AND DOCUMENTATION FURNISHED HEREUNDER IS LIMITED TO THE REQUEST FOR
          ADAP, AT ADAP'S OPTION, TO REFUND THAT NET PRICE FOR THE ITEMS AND
          MATTERS INVOLVED, EXCEPT THAT IN THE CASE OF A BREACH OF WARRANTY,
          BUYER'S SOLE REMEDY IS TO RETURN THE PRODUCT TO ADAP FOR REPAIR OR
          REPLACEMENT IN ACCORDANCE WITH THE "WARRANTY" SECTION OF THESE TERMS
          AND CONDITIONS.

                                    Page 17
<PAGE>   18

     B.   WITH RESPECT TO SERVICES, ADAP'S LIABILITY FOR ANY SERVICE IS
          LIMITED TO THE RE-PERFORMANCE OF THE SERVICE. ADAP DOES NOT WARRANTY
          PROPOGATION OR PATH PERFORMANCE. ALL SURVEYS ARE ACCURATE AS OF THE
          DATE THE SURVEY WAS CONDUCTED.

     C.   IN NO EVENT WILL ADAP BE LIABLE TO BUYER, OR WILL BUYER BE LIABLE
          TO ADAP, FOR (I) REPROCUREMENT COSTS; (II) INDIRECT, INCIDENTAL,
          SPECIAL, OR CONSEQUENTIAL DAMAGES; (III) ANY DAMAGES WHATSOEVER
          RESULTING FROM LOSS OF USE, DATA OR PROFITS ARISING OUT OF OR IN
          CONNECTION WITH THIS AGREEMENT OR THE USE OR PERFORMANCE OF ADAP
          PRODUCTS, WHETHER IN AN ACTION OF CONTRACT OR TORT, INCLUDING
          NEGLIGENCE AND STRICT LIABILITY, EVEN IF THE OTHER PARTY HAS BEEN
          ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

     D.   NO ACTION, WHETHER IN CONTRACT OR TORT, INCLUDING NEGLIGENCE, ARISING
          OUT OF OR IN CONNECTION WITH THIS AGREEMENT MAY BE BROUGHT BY EITHER
          PARTY MORE THAN EIGHTEEN (18) MONTHS AFTER THE CAUSE OF ACTION HAS
          ACCRUED, EXCEPT THAT AN ACTION FOR NON-PAYMENT MAY BE BROUGHT
          WITHIN EIGHTEEN (18) MONTHS OF THE DATE OF LAST PAYMENT.

13.  GENERAL PROVISIONS.

     a.   The rights and obligations under these terms and conditions may not be
          assigned without ADAP's prior written consent and any attempt to
          do so without such consent will be void.

     b.   Buyer will pay to ADAP all costs, fees and expenses (including
          attorneys' fee) incurred by ADAP in enforcing, or attempting to
          enforce, any of its rights under these terms and conditions or any
          contract of sale between them.

     c.   All rights and remedies, whether conferred hereby or by any other
          instrument or law will be cumulative and may be exercised singularly
          or concurrently. Failure by either party to enforce any contract
          terms will not be deemed a waiver of future enforcement of that nor
          of any other term. If any provisions of this contract are held invalid
          under any applicable law, rule, regulation or treaty, such invalidity
          will not affect other provisions of this contract which can be given
          effect without the invalid provisions and to this end, the
          provisions of this contract are declared to be severable.
          Notwithstanding the above, such invalid provision or clause will be
          construed, to the extent possible, in accordance with the original
          intent of the parties.

     d.   Any typographical, clerical or other error or omission in any sales
          literature, quotation, price list, acceptance of offer, invoice or
          other document or information issued by ADAP will be subject to
          correction without any liability on the part of ADAP.

     e.   Where products include radio frequency communications equipment,
          certain regulations of telecommunications regulatory authorities
          apply. It is the sole responsibility of the Buyer to ensure
          compliance with all such regulations and all other applicable
          laws and rules and to procure and maintain at its own expense any
          relevant license from such regulatory authority to install, operate
          and maintain the equipment.

                                     Page 18

<PAGE>   19

                                    EXHIBIT D

                        SOFTWARE LICENSE AND SUB-LICENSE

Set out below are the terms and conditions of the software license granted by
Adaptive Broadband to Buyer. In sub-licensing software to its customers, Buyer
shall incorporate in such sub-licenses terms which offer no less degree of
protection than those set out below:

1.   The Software and the documentation are unpublished copyright works and may
     be used on any installation with a configuration mentioned in the
     Agreement, provided the Software is in use on only one installation at any
     one time.

2.   Neither the Software nor the documentation may be copied in whole or in
     part, except for backup and archival purposes.

3.   The copyright notices and trademarks contained in the Software, on the data
     medium, and in the documentation as supplied to Buyer must appear on all
     copies made by Buyer.

4.   Save for Buyer's right to grant sub-licenses to its customers in the
     Territory and Market to use the Software in object code form, Buyer may not
     transfer part, download, or in other way make available to others the
     Software and the documentation delivered to it.

5.   Buyer shall not have the right to modify the Software or to create
     derivative works based on the Software, save as provided under applicable
     laws.

6.   No warranty applies if failure of the Software has resulted from misuse or
     misappropriation.

If a new release of the Software contains new functions, and Buyer wants to use
these new functions, the new release shall be subject to a supplementary charge.
No license is granted for any new release until Buyer pays associated
additional fees. Buyer will be responsible for costs of software/hardware
upgrades of equipment supplied by third parties to support such new releases.

Any replacement of the Software will be guaranteed for the remainder of the
original warranty period or 3 months, whichever is longer.

                                    Page 19
<PAGE>   20

                                    EXHIBIT E

                    ENHANCEMENTS AND FIELD TRIAL VERIFICATION
                                   APPENDIX E

            USE OF ADAPTIVE BROADBAND WITHIN I(3)S DATA ENVELOPE(TM)

This attachment is an analysis of how I(3)S can use the Adaptive Broadband
equipment as part of the I(3)S Data Envelope(TM) product architecture for
delivering broadband access to the Internet over forward deployed Ethernet
switches and other in-unit technologies. Below is a link-by-link and
device-by-device description of a property network architecture, detailing what
operations are required and what operations must not be performed along the
path. At the end is a detailed list of required changes to the Adaptive
Broadband product to satisfy the architectural model as well as other security,
configuration and management items.

                                  [FLOW CHART]

                                    Page 20
<PAGE>   21

WORKING FROM THE PC TO THE CPE ROUTER

F    10 Mbps Ethernet
     PCs are attached to the Edge Ethernet Switch via 10 Mb Ethernet.

Edge Ethernet Switch
     Conforming to the requirements of the Data Envelope(TM), the switch does
     not perform any subscriber port (S) to subscriber port (S) switching. All
     traffic (broadcast and unicasts) which enters a subscriber port (S) must be
     switched out the trunk port (T). The Edge Ethernet Switch will function as
     a learning bridge and create a MAC table to identify all MAC addresses out
     each port. Multiple PCs (and MAC addresses) may be attached to a hub on a
     single switch port.

E    10/100 Mbps Ethernet
     The aggregation of traffic from multiple 10 Mbps sources requires a higher
     bandwidth trunk.

Adaptive Broadband Subscriber Unit
     This device must provide a 10/100 Mbps Ethernet interface at the subscriber
     port (S). Any bit presented to S must be sent out T. There is no need to
     perform any MAC layer or IP layer analysis. All traffic must be presented
     to the router, even IP layer peer to peer traffic.

D    25 Mbps Pt-Mpt Wireless

Adaptive Broadband Access Point
     This device must provide a 10/100 Mbps Ethernet interface at the trunk port
     (T). Any bit presented to S must be sent out T. All traffic must be
     presented to the router, even IP layer peer to peer traffic.

C    10/100 Mbps Ethernet

Hub Ethernet Switch
     Conforming to the requirements of the Data Envelope(TM), the switch does
     not perform any subscriber port (S) to subscriber port (S) switching. All
     traffic (broadcast and unicasts) which enters a subscriber port (S) must be
     switched out the trunk port (T). The Hub Ethernet Switch will function as a
     learning bridge and create a MAC table to identify all MAC addresses out
     each port.

B    10/100 Mbps Ethernet

                                    Page 21
<PAGE>   22

Router

     The main element in the Data Envelope(TM), all packets transmitted on the
     property enter the router for processing, accounting, and forwarding. The
     router sees all PCs on the property on the same IP subnet and in the same
     broadcast domain. The router can communicate with all PCs via broadcasts or
     multicasts, which will be replicated as necessary by the Ethernet switches.

A    T1 or greater to POP

WORKING FROM THE CPE ROUTER TO THE PC

A    T1 or greater from POP

Router
     The main element in the Data Envelope(TM), all packets transmitted on the
     property enter the router for processing, accounting, and forwarding. The
     router sees all PCs on the property on the same IP subnet and in the same
     broadcast domain. The router can communicate with all PCs via broadcasts or
     multicasts, which will be replicated as necessary by the Ethernet switches.
     The router can ARP for all PCs by sending a Layer 2 broadcast. The ARP
     reply is only seen by the router.

B    10/100 Mbps Ethernet

Hub Ethernet Switch
     Functioning as a standard Ethernet switch, the switch will flood broadcast
     frames and search its MAC table for the correct port to send an outbound
     unicast packet. At this layer, the switch will have the MAC address of all
     the PCs attached to a downstream switch.

C    10/100 Mbps Ethernet

Adaptive Broadband Access Point
     This device must provide a 10/100 Mbps Ethernet interface at the trunk port
     (T). Any frame presented to t must be sent out s and vice-versa.

D    25 Mbps Pt-Mpt Wireless
     All downstream traffic shares the 25 Mbps data rate.

Adaptive Broadband Subscriber Unit
     This device must provide a 10/100 Mbps Ethernet interface at the subscriber
     port (S). Any frame presented to T must be sent out S.

E    10/100 Mbps Ethernet

Edge Ethernet Switch
     This Ethernet switch will receive all traffic transmitted from the Access
     Point on the Pt-Pt PVC to which its Subscriber Unit is attached. The switch
     will drop all traffic with a

                                    Page 22
<PAGE>   23

     destination MAC address which has not been learned on a subscriber
     port (S). Any traffic with a destination MAC address learned on a
     subscriber port (S) will be forwarded out the appropriate port only.

F    10 Mbps Ethernet
     PCs are attached to the Edge Ethernet Switch via 10 Mb Ethernet.

REQUIRED CHANGES TO ADAPTIVE BROADBAND EQUIPMENT TO MEET I(3)S DATA ENVELOPE(TM)
REQUIREMENTS

Access Point

o    The Access Point (AP) must function at layer 1 and layer 2 only.

o    The AP will support a secure handshake with Subscriber Unit (SU) and/or
     encryption of data to SU

o    The AP will only connect to an SU with the properly configured PVC to
     establish a PVC connection.

o    The AP will function as a Layer 2 MAC Learning Bridge. The AB Access Point
     equipment will function as a Layer 2 MAC learning bridge, providing Pt-Pt
     PVCs to each Subscriber Terminal. The Access Point will correctly implement
     the S to T isolated data flow model correctly, ensuring no S to S
     communication of broadcast or unicast packets. The Access Point will place
     the downstream packet on the correct PVC to be received by only a single
     Subscriber Terminal and forwarded to the correct Ethernet switch.

Subscriber Unit

o    The SU will not function at Layer 3 for subscriber traffic flow.

o    The SU will not learn IP addresses.

o    The SU will not require an IP Subnet per SU.

o    The SU will function at layer 1 and layer 2 only for subscriber traffic
     flow.

o    The SU will support a secure handshake with AP and/or encryption of data to
     the AP.

o    The SU will only connect to an AP with the properly configured PVC to
     establish a PVC connection.

                                    Page 23
<PAGE>   24

                                    EXHIBIT F

                   ACCEPTANCE TEST, PROCEDURES AND PARAMETERS

                                   APPENDIX F

                         ACCEPTANCE TESTING REQUIREMENTS
                                   Revision E

                              General System tests

Item      Description
Number

GS-01     Configuration data is stored locally on each SU and AP device and may
          be power cycled, reboot, and begin forwarding traffic appropriately
          without communication with the network server or network management
          station.

GS-02     Configuration files may be downloaded to an SU or AP device remotely
          via secure RUPEE over TCP/IP (Specifically: PVC configuration, IP
          address assignments, wireless interface configuration, all firmware
          and software).

                               SU - General tests

Item      Description
Number

SU-G-01   The SU builds a bridge table based on Ethernet MAC address only as it
          receives packets in the S and T interface of the SU.

SU-G-02   The bridge table may be viewed via network management, direct SNMP to
          the SU or through a management station proxy.

SU-G-03   The SU maintains counters for received and transmitted MAC layer
          frames and cells.

SU-G-04   The SU will accept all input ethernet traffic on the S interface of
          the device on a standard RJ-45 - 10 Mb half-duplex Ethernet
          connection.

                           SU - Upstream from PC tests

Item      Description
Number

SU-U-01   Valid upstream unicast packets received on an S interface of the SU
          are always forwarded out the T interface of the SU.

SU-U-02   Valid upstream broadcast packets received on an S interface of the SU
          are always forwarded out the T interface of the SU.

SU-U-03   Valid upstream multicast packets received on an S interface of the SU
          are always forwarded out the T interface of the SU.

SU-U-04   The SU does forward packets with source and destination MAC addresses
          on the S interface of the SU out the T interface, and the T interface
          only.

SU-U-05   All packets arriving at the S interface of the SU are forwarded out
          the T interface of the SU.

SU-U-06   No packets arriving at the S interface of the SU are forwarded back
          out the S interface of the SU.

                                    Page 24
<PAGE>   25

                          SU - Downstream to PC tests

Item      Description
Number

SU-D-01   Valid downstream unicast packets received on a T interface of the SU
          are either:
               -Always forwarded out the S interface of the SU (With the
               exception of datagrams terminated within the SU itself)

SU-D-02   Valid downstream broadcast packets received on a T interface of the SU
          are always forwarded out the S interface of the SU.

SU-D-03   Valid downstream multicast packets received on a T interface of the
          SU are always forwarded out the S interface of the SU with the
          exception of some management packets addressed to the SU which are not
          passed on

SU-D-04   The SU does not forward packets with source and destination MAC
          addresses on the T interface of the SU out the S interface; the
          packets are discarded.

SU-D-05   No packets arriving at the T interface of the SU are forwarded back
          out the T interface of the SU.

                               AP - General tests

Item      Description
Number

AP-G-01   The AP builds a bridge table based on Ethernet MAC address only as it
          receives packets in the S and T interface of the SU.

AP-G-02   The bridge table may be viewed via network management, direct SNMP to
          the AP or through a management station proxy.

AP-G-03   The AP maintains counters for received and transmitted MAC layer
          frames and cells.

AP-G-04   The AP will accept all input ethernet traffic on the T interface of
          the device on a standard RJ-45-10 Mb half-duplex Ethernet
          connection.

                           AP - Upstream from PC tests

Item      Description
Number

AP-U-01   Upstream unicast packets received on an S interface of the AP are
          always forwarded out the T interface of the AP with the exception of
          some SU management information packets.

AP-U-02   Upstream broadcast packets received on an S interface of the AP are
          always forwarded out the T interface of the AP.

AP-U-03   Upstream multicast packets received on an S interface of the AP are
          always forwarded out the T interface of the AP with the exception of
          some SU management information packets.

AP-U-04   The AP does forward packets with source and destination MAC addresses
          on the S interface of the AP out the T interface, and the T interface
          only.

AP-U-05   All packets arriving at the S interface of the AP are forwarded out
          the T interface of the AP with the exception of some SU management
          information packets.

AP-U-06   No packets arriving at the S interface of the SU are forwarded back
          out the S interface of the SU.

AP-U-07   All packets forwarded out the T interface of the AP will be forwarded
          out the 10 Mb Ethernet interface identical to the packets received on
          the S interface of the SU; no additional headers from the original PC
          authored Ethernet packet will be presented.

                                    Page 25
<PAGE>   26

                           AP - Downstream to PC tests

Item      Description
Number

AP-D-01   Downstream unicast packets received on a T interface of the AP are
          only forwarded out the S interface of the AP if the destination MAC
          address is located in the bridge table and designates the S interface
          as the interface on which the address was learned

AP-D-02   Downstream broadcast packets received on a T interface of the AP are
          always forwarded out the S interface of the AP.

AP-D-03   Downstream multicast packets received on a T interface of the AP are
          always forwarded out the S interface of the AP with the exception of
          some AP management information packets.

AP-D-04   The AP does not forward packets with source and destination MAC
          addresses on the T interface of the AP out the S interface; the
          packets are discarded.

AP-D-05   No packets arriving at the T interface of the AP are forwarded back
          out the T interface of the AP.

                              AP 1483 bridge tests

Item      Description
Number

AP-BR-01  The 1483 bridge table in any AP must support a minimum of 250
          simultaneous bridge entries.

AP-BR-02  As packets are learned from upstream traffic, the MAC address is
          placed into a bridge table associated with the PVC on which the packet
          was received.

AP-BR-03  Learned MAC addressed must time-out every hour.

AP-BR-04  Entries in an instance of the 1483 bridge tables must capable or being
          cleared via network management interaction

AP-BR-05  Downstream packets will consult the bridge table and forward the
          packet out the S interface on the appropriate PVC.

AP-BR-06  If a PVC to a SU goes down, the bridge table must be cleared.

                                    Page 26
<PAGE>   27

                            Network Management tests

Item      Description
Number

NM-01     A single ADAP NMS will be located in the Irving, TX NOC and can
          support up to 100 ADAP Control Servers.

NM-02     The ADAP NMS will communicate with the ADAP Control Servers via a TCP
          over IP connection.

NM-03     The ADAP Control Server may be configured to only accept network
          management IP connections from a designated subnet and from a discrete
          set of IP addresses. All other network management connections are
          refused and logged.

NM-04     The ADAP Control Server and ADAP NMS connection must be validated
          through a security mechanism, such as shared key.

NM-05     The ADAP Control Server will be located in I3S POPs and communicated
          with on-property APs via a TCP over IP connection.

NM-06     The ADAP Control Server will support up to 1000 simultaneous TCP
          connections to the APs and maintain a response time of less than 2
          seconds.

NM-07     The AP may be configured to only accept network management IP
          connections from a designated subnet and from a discrete set of IP
          addresses. All other network management connections are refused and
          logged.

NM-08     The ADAP Control Server and ADAP NMS connection must be validated
          through a security mechanism, such as shared key.

NM-09     The information exchanged, gathered, etc... between the AP and ADAP
          Control Server can be controlled, minimized, and tailored.

NM-10     The ADAP Control Server will initiate and establish a session based
          UDP over IP connection with each configured AP or SU. UDP packets
          which arrive and violate the session flow will be discarded and
          logged.

NM-11     An AP will forward network management traffic between the ADAP Control
          Server and the designated SU over the specified and designated network
          management PVC configured between the AP and SU.

NM-12     The AP and SU connection must be validated through a security
          mechanism, such as shared key.

NM-13     An AP can be configured to connect to a primary and a secondary ADAP
          Control Server. If the primary is not available after a reasonable
          effort, the AP will connect to the secondary.

NM-14     The IP addresses assigned to AP and SU devices for network management
          may be changed dynamically and through network management.

NM-15     AP and SU devices are assigned a single IP address for network
          management. The IP address may be from the globally non-routable
          ranges. An AP and all subordinate SU devices must share a common IP
          subnet for network management. All devices must support variable
          length subnet masks.

                                    Page 27

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