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                                                                    EXHIBIT 10.2



SUBLEASE

     This Sublease is made as of the 27th day of July, 1998, by and between GTE
Intelligent Network Services Incorporated, a Delaware corporation ("Subtenant"),
and Micro-Media Solutions Inc., a Texas corporation and successor in interest to
Media Solutions ("Sublandlord").

     RECITALS

     A. Sublandlord is the tenant under that certain Lease Agreement dated as of
June 6, 1994 as amended by Addendum to Lease Agreement, dated March 11, 1996,
and as further amended by Second Amendment to Lease Agreement, dated
concurrently herewith (collectively, the "Master Lease") with WBH, Ltd., a Texas
limited partnership and successor in interest to W.B. Houston & Company (the
"Landlord"). A copy of the Master Lease, with certain economic terms deleted, is
attached hereto as Exhibit A. Pursuant to the Master Lease, Sublandlord is
leasing approximately 36,100 rentable square feet of space (the "Premises"),
with 19,100 square feet in the building located at 1210 East Fifth, Austin,
Texas, and 17,000 square feet in the building located at 501 Waller, Austin,
Texas.

     B. Sublandlord desires to sublease to and Subtenant desires to sublease
from Sublandlord a certain portion of the Premises located at 501 Waller, Lots
10-12, Block 4, Outlot 3, Division A, City of Austin, Travis County, Texas (the
"Building") consisting of approximately 10,000 rentable square feet of floor
space (the "Subleased Premises") more particularly shown on Exhibit B, attached
hereto.

     AGREEMENT

     The parties hereto agree as follows:

     1. Sublease. Sublandlord hereby subleases and demises to Subtenant and
Subtenant hereby hires, subleases and takes from Sublandlord the Subleased
Premises.

     2. Term. The term of this Sublease shall commence on the later of the
execution and delivery of this Sublease by Sublandlord, Subtenant, and Landlord,
or delivery of the Subleased Premises to Subtenant ("Commencement Date"). The
term shall end, unless sooner terminated as provided herein, on the day
proceeding the 10th anniversary of the Commencement Date. Sublandlord shall
deliver the Subleased Premises to Subtenant by not later than August 17, 1998.

     3. Rent.

         3.1 Base Rent. Commencing on the Commencement Date, Subtenant shall pay
monthly base rent ("Base Rent") during


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the term of this Sublease of $3.75 per square foot per year ($3,125 per month).
On each anniversary of the Commencement Date, the Base Rent shall increase by
3%, as shown on Exhibit "F".

         3.2 Additional Rental. In addition to Base Rent, commencing with the
calendar year which begins on January 1, 1999 and for each calendar year
thereafter, Subtenant shall pay, as Additional Rental under this Sublease,
Subtenant's pro rata share of all increases in Additional Rental that are passed
through to Sublandlord pursuant to Section 3.2 of the Master Lease. Subtenant's
pro rata share is determined by multiplying 27.70% (the "Subtenant Escalation
Percentage") by the annual increases in Additional Rental for the Premises which
are imposed pursuant to the terms of the Master Lease. Commencing January 1,
1999, Subtenant shall reimburse Sublandlord monthly for 1/12 of the pro rata
share of such increases as are estimated by Landlord and imposed pursuant to the
Master Lease, which amount shall be adjusted to reflect the actual share as
determined by and in accordance with the Master Lease. The current Subtenant
Escalation Percentage has been calculated by dividing 10,000, which is the total
number of rentable square feet in the Subleased Premises, by 36,100, which is
the total number of usable square feet in the Premises as provided in the Master
Lease. Subtenant shall not be obligated to reimburse Sublandlord (or to pay to
Landlord, in the event of a direct lease) the amount of $300 per month that
Sublandlord is obligated to pay Landlord pursuant to Section 5 of the Second
Addendum.

         3.3 Partial Month. The Base Rent and any Additional Rental shall be
prorated as to any partial month.

         3.4 Supporting Documents. Sublandlord agrees to (i) reasonably
cooperate with Subtenant, at no cost to Sublandlord, in requesting from Landlord
supporting documentation and backup for Operating Expenses used to calculate
Additional Rental under the Master Lease, and (ii) make reasonable efforts, not
more frequently than once in each calendar year during the term of this
Sublease, to obtain Landlord's permission to audit said books and records on
Subtenant's behalf and at Subtenant's sole cost and expense. If having obtained
Landlord's permission to conduct an audit of Landlord's books and records and,
upon completion of such audit an overcharge or other discrepancy is revealed
thereby, then to the extent any such amounts have been (a) paid by Subtenant
pursuant to the Sublease and (b) refunded to Sublandlord by Landlord,
Sublandlord shall reimburse Subtenant


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for its pro rata share of any such overcharge or discrepancy. Sublandlord's sole
obligation hereunder shall be to make reasonable attempts to obtain Landlord's
cooperation with respect to its books and records and Sublandlord shall not be
liable to Subtenant as a result of or in connection with any discrepancy or
inaccuracy in Landlord's books, records or method of accounting.

         3.5 No Security Deposit. Subtenant shall not be required to pay a
security deposit.

     4. Use. Notwithstanding anything in the Master Lease to the contrary, the
Subtenant shall have the following rights:

         4.1 Subtenant's Use of Subleased Premises and Project.

               4.1.1 During Construction. During construction, Subtenant is
permitted to store and stage equipment and material in that certain warehouse
located outside of the footprint of the R POP, and to engage in welding inside
of the Subleased Premises. During construction, Subtenant shall have 24 hour per
day, 7 day per week access to and use of the Subleased Premises, freight and
passenger elevators and hoists, electricity, water, air conditioning, and other
utilities; provided that Subtenant shall pay the actual cost of utilities used
by Subtenant outside of generally accepted business hours. Sublandlord and
Landlord agree that Subtenant shall be provided with adequate parking for all of
Subtenant's contractors during construction. Subtenant's subcontractors, shall
not, however park trailers in Landlord's parking lot.

               4.1.2 Throughout Term. Subtenant is permitted (a) to construct,
maintain, operate and repair electronic, transmitting and receiving equipment
and supporting structures on the Subleased Premises, (b) to construct, maintain,
operate and repair an equipment room on the Subleased Premises, including the
construction of an upgraded fire suppression system, (c) to install, maintain,
operate, and repair electrical and other utility lines, transmission lines, and
telecommunications conduit and cabling (collectively, the "Conduits") for any
purpose, including, without limitation, connecting the Subleased Premises to
other entities located within the Project (as defined in the Master Lease) or at
other locations (but only so long as Subtenant has the consent of such other
entities), and in such locations on the Project as set forth in plans and
specifications, which plans and specifications shall be subject

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to Sublandlord's and Landlord's approval, which approval shall not be
unreasonably withheld, conditioned or delayed, (d) reasonable ingress and egress
over existing roadways on the Project for Subtenant's trucks and other vehicles,
to maintain Subtenant's equipment and the Conduits (collectively, "Equipment"),
(e) to use the Subleased Premises for any activity related to the provision of
telecommunication services, including, without limitation, the right to transmit
data, VOX, and other transmissions, (f) access to all Common Areas, including
restroom facilities, and (g) to install, maintain, operate and repair condenser
units ("Condenser") on the roof of the Building (provided any damage to the roof
resulting from such acts by Subtenant shall be repaired at the sole cost of
Subtenant), and (h) at Sublessee's sole cost and expense, to upgrade the
infrastructure of the Building, including, but not limited to, the fire
suppression system, electrical, water, and telecommunications conduit. The
Equipment shall include, without limitation, the Condenser, batteries,
uninterruptible power supply, fuel tank, and such other equipment as is listed
on Exhibit "C" attached hereto and shall be for Subtenant's exclusive use.
Subtenant shall have access to and use of the Subleased Premises, the Project
and the Conduits, 24 hours per day, 365 days per year.

         4.2 Subtenant's Use of Conduit Ducts. Subtenant shall have the right to
install, maintain, operate and repair the Conduits in any of Sublandlord's
conduit ducts located on the Project, so long as Subtenant's use of the Conduits
does not interfere with Sublandlord's or any subsequent occupant of the
Building's use of Sublandlord's or such other occupant's conduit ducts located
on the Project. Sublandlord shall not install and shall not permit other tenants
of the Building to install equipment in the conduit ducts which interfere with
the Equipment. Subtenant shall also have the right to make connections with any
offsite telecommunications or other companies whose facilities may be accessed
through the Conduits point of entry in the Building or on the Project.

         4.3 Unmanned Use. Sublandlord acknowledges and agrees that the
operation of the Subleased Premises may be unmanned during the Sublease Term,
and Subtenant shall not be deemed to be in default or breach of this Sublease if
Subtenant


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does not have employees, personnel or other agents present at the Subleased
Premises so long as Subtenant complies with all of Subtenant's obligations as
set forth in the Sublease, including payment of rent in accordance with this
Sublease. Nothing contained in this Sublease shall prevent Subtenant from having
employees on site, whether on a permanent or temporary basis.

     5. Initial Installation and Testing. Subtenant shall have the right, at
Subtenant's sole cost and expense, at any time following the execution of this
Sublease and prior to and after the Commencement Date, to enter upon the Project
to carry out any tests, inspections, pre-installation and installation
activities on the Project as necessary for the construction and installation of
the Equipment, including without limitation, engineering and environmental
surveys, physical inspections, soil test borings, and underground trenching.
Immediately following the completion of such tests, inspections or
pre-installation activities, Subtenant shall, at Subtenant's sole cost and
expense, repair any damage to the Project caused by such inspections or pre-
installation activities, including repaving and re-landscaping any affected
areas of the Project.

Any such entry onto the Project prior to the Commencement Date of the Sublease
shall be on all of the terms and provisions of the Sublease, except for
Subtenant's obligation to pay rent.

     6. Equipment Ownership; Surrender. Notwithstanding anything to the contrary
in the Master Lease, the Equipment shall be the property of and owned by
Subtenant throughout the Sublease Term, and shall in no event be deemed
fixtures, even if affixed to the Subleased Premises or Project. On or before the
Expiration Date or earlier termination of this Sublease, Subtenant shall remove
its Equipment from the Subleased Premises and Project. Notwithstanding anything
to the contrary in the foregoing, Subtenant shall not be required to remove any
Conduits, Subtenant's HVAC Unit (as defined in Section 7.3 below), Subtenant's
Generator (as defined in Section 7.4.1 below), or the fire or lightening
protection systems being installed pursuant to Section 4.2 of Landlord's
Consent, from the Subleased Premises or the Project, all of which if not so
removed by Subtenant, which removal shall be at Subtenant's sole option, shall
become the property of Landlord upon the Expiration Date or earlier termination
of this Sublease. Sublandlord and Landlord hereby expressly waive and release
any and all contractual liens and security interests or constitutional and/or
statutory liens


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and security interests arising by operation of law or under the Sublease to
which Sublandlord or Landlord might now or hereafter be entitled on any of the
property of Subtenant, including without limitation, the Equipment, Subtenant's
HVAC Unit or Subtenant's Generator. Landlord and Sublandlord further agree that
the Equipment, Subtenant's HVAC Unit, and Subtenant's Generator shall be exempt
from execution, foreclosure, sale, levy, attachment, for any Subtenant default
hereunder, and that the Equipment, Subtenant's HVAC Unit, and Subtenant's
Generator may be removed at any time from the Subleased Premises or the Project
by Subtenant.

     7. Utilities.

         7.1 Supply of Electrical Power. Landlord shall have no obligation to
provide utilities to the Subleased Premises, but Subtenant shall make all its
own arrangements in such regard. Subtenant's electrical power requirements are
described in Exhibit "D" attached to this Sublease. Since Subtenant has
determined that the Building's electrical system does not have sufficient
capacity to accommodate Subtenant's needs, Subtenant, at its sole cost and
expense, shall upgrade the Building's electrical system, as necessary to
accommodate the Equipment and Subtenant's HVAC Unit. Subtenant, at its sole cost
and expense, shall install a transformer tying into the Project's bus duct
system to obtain the electrical supply for the Subleased Premises and to
separately meter Subtenant's electrical power usage at the Subleased Premises.

          7.2 Payment for Electrical Usage. Subtenant shall have its electrical
usage directly metered and shall pay the local public utility directly for all
such electric usage (including electrical usage for Subtenant's HVAC Unit, as
defined below) as shown by such meters.

          7.3 Subtenant's HVAC Units. In addition, or at Subtenant's option,
instead of, the HVAC utilities supplied to the Subleased Premises by
Sublandlord, Subtenant shall have the right, at Subtenant's option, to install
in the Subleased Premises or elsewhere on the Project, in such location as
reasonably approved by Landlord, one or more separate self-contained twenty-four
(24) hour a day heating, ventilation and air-conditioning ("HVAC") HVAC units
(collectively, whether one or more, "Subtenant's HVAC Unit") subject to
Landlord's prior approval of the plans and specifications for the work and


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electrical requirements of Subtenant's HVAC Unit, which approval shall not be
unreasonably withheld, conditioned, or delayed. Subtenant shall pay all costs of
electrical power for such unit in the manner set forth in Section 7.2 above.

         7.4 Emergency Power Generators.

               7.4.1 Installation of Subtenant's Generators. Subtenant shall
have the right, at any time during the Sublease Term, at Subtenant's option and
at Subtenant's sole cost and expense to (a) install one or more emergency power
generators (collectively, whether one or more, "Subtenant's Generator") on the
Subleased Premises or elsewhere on the Project, in such location as reasonably
approved by Landlord, to provide back-up emergency power for the Equipment and
for Subtenant's HVAC Unit, and (b) store fuel on the Subleased Premises or
elsewhere on the Project, in such locations and in such manner as reasonably
approved by Landlord, in such amounts as Subtenant reasonably determines
necessary for Subtenant's Generator.

     8. No Interference; Relocation.

          8.1 No Interference. Landlord and Sublandlord each agrees that neither
it nor its agents, employees, or contractors (collectively, the "Sublandlord
Parties") shall interfere in any way, or authorize any other tenant or other
third party to take any actions that could interfere in any way, with the
Equipment or with Subtenant's access to the Subleased Premises, the Conduits,
Subtenant's HVAC Unit, or Subtenant's Generator (the "Interference"). Landlord
and Sublandlord each agree that prior to carrying out (or authorizing any other
tenant or other third party to carry out) any construction, maintenance or
repair activities (other than emergencies, in which case notice shall be given
to Subtenant as quickly as possible, with best efforts being made to notify
Subtenant prior to commencement of the activity) which are in the vicinity of
the Subleased Premises, the Conduits, Subtenant's HVAC Unit, or Subtenant's
Generator, Sublandlord and Landlord shall provide three (3) days' prior written
notice of such parties' intent to carry out such construction, maintenance or
repair work, including the date, time and location in which such work will take
place. Notwithstanding any Notices provision in the Sublease, Landlord and
Sublandlord shall provide such written notice to the following Subtenant
representative at the following address:


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Rick Wyss, Director-Strategic Services, Assets, GTE Support A, 5800 Campus
Circle Drive, Irving, Texas 75063. Subtenant shall have the right to monitor and
inspect such work at Subtenant's own risk, and at Subtenant's sole cost and
expense. Sublandlord and Sublandlord Parties shall exercise all due care in
carrying out such work as they perform, and Landlord shall notify such other
parties that they are obligated to exercise due care in carrying out such work.
Landlord and Sublandlord shall immediately notify the Subtenant's designated
contact person by telephone or facsimile in the event of fire, power failure,
bomb threats, or other unplanned events of which Landlord or Sublandlord becomes
aware which could adversely impact Subtenant's operations.

          8.2 Remedies. Upon written notice from Subtenant stating with
specificity that an Interference has been created in violation of Section 8.1
above, Sublandlord or Landlord, as applicable, shall promptly take all
reasonably necessary measures at Sublandlord's or Landlord's, as applicable,
sole cost and expense, to eliminate the Interference, including hiring agents to
work extended hours, until the Interference is eliminated. If Landlord or
Sublandlord, as applicable, does not eliminate the Interference, Subtenant shall
have the right, at Subtenant's option, in addition to any other remedy at law or
in equity, to (a) eliminate the Interference, and deduct the cost of eliminating
the Interference from the Base Rent next due, (b) obtain injunctive relief
enjoining or restraining whatever Interference may have occurred or be
occurring, without posting a bond or other security and without proving damages,
it being expressly recognized by Sublandlord that any Interference will cause
irreparable harm to Subtenant which cannot be fully compensable by damages, or
(c) immediately terminate this Sublease, in which event, this Sublease shall be
of no further force and effect and Subtenant shall have no further obligations
hereunder.

          8.3 Relocation. In no event shall Sublandlord or Landlord relocate
Subtenant or the Equipment to other premises, or require Subtenant to relocate
its Equipment for any length of time to any other location, either on the
Project or elsewhere.


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     9. Access. Notwithstanding anything in the Master Lease to the contrary,
access rights shall be established as follows:

         9.1 Subleased Premises. Sublandlord and Landlord acknowledge and agree
that the Equipment at the Subleased Premises is highly sensitive, requiring
specialized maintenance and care. It is essential to the successful operation of
Subtenant's business that access to the Subleased Premises be restricted to
Subtenant's employees and agents. Sublandlord and Landlord shall only have
access to the Subleased Premises for the purpose of making such alterations,
repairs, improvements or additions to the Subleased Premises as required
pursuant to this Sublease or the Master Lease. Except in the case of
Emergencies, as described below, Sublandlord or Sublandlord Parties shall give
no less than two (2) days' prior written notice to Subtenant prior to each entry
onto the Subleased Premises and upon each such entry, Sublandlord Parties shall
be accompanied by a representative of Subtenant. Sublandlord acknowledges that
due to the foregoing reasons, neither Sublandlord nor Landlord shall have a key
to the Subleased Premises during the Sublease Term.

          9.2 Emergency Access - Subleased Premises. In the event of an
Emergency, Landlord, Sublandlord, or emergency personnel including fire or
police department personnel, may use force to enter the Subleased Premises in
order to remedy such Emergency; provided, however that Landlord, Sublandlord,
and such emergency personnel shall use reasonable efforts to avoid causing
damage to or interfering with the Equipment. Subtenant shall, upon receipt of
notice from Landlord or Sublandlord, pay for all damage to the Subleased
Premises or Project resulting from such forced entry by Landlord, Sublandlord,
or such emergency personnel into the Subleased Premises, including without
limitation, damage to the door leading into the Subleased Premises due to an
Emergency. For purposes of this Section, an "Emergency" shall mean a condition
in the Subleased Premises reasonably likely to cause (a) imminent bodily harm to
persons at the Project or (b) imminent and substantial damage to the Project.

          9.3 Project. Landlord acknowledges and agrees that in order to
accommodate Subtenant's specialized utility needs, Subtenant shall have a key to
each and every mechanical room located at the Project which contains equipment
or cabling of any kind relating to the Subleased Premises or the Equipment,
including without limitation, boiler rooms and electrical rooms (the "Subtenant
Access Mechanical Rooms"). Landlord and Sublandlord further acknowledge and
agree that it is essential to the successful operation of Subtenant's business
that access to each and every Subtenant Access Mechanical Room be restricted in


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order to protect the special requirements of the Equipment and Subtenant's
specialized utility needs.

     10. Assignment; Subletting. Subtenant shall have the right, without first
obtaining the consent of Landlord or Sublandlord, and without Landlord or
Sublandlord having the right of recapture, to assign this Sublease or sublease
the Subleased Premises to (a) any entity resulting from a merger or
consolidation of Subtenant with any organization; (b) any entity purchasing
substantially all of the stock or assets of Subtenant; (c) any entity succeeding
to the business and assets of Subtenant; (d) any entity which controls, or is
controlled by, is under common control with Subtenant; and (e) any public
utility or subsidiary or affiliate thereof. No change of stock ownership or
control of Subtenant shall constitute an assignment hereunder.
 Subtenant shall provide Landlord and Sublandlord with written notice of such
assignment or sublease within ten (10) days after each such occurrence.
Sublandlord shall have the right to payment of all excess sums over the rent
payable hereunder after Subtenant's recovery of its out-of-pocket expenses,
including, without limitation, brokers' fees, attorneys' fees, and tenant
improvements (including the unamortized portion of Subtenant's initial costs of
construction). Landlord shall have the right to sell, transfer, or assign its
interest under the Master Lease in which event Landlord shall be released from
all obligations under this Sublease and the attached Consent after the effective
date of such sale, transfer, or assignment and upon the purchaser, transferee or
assignee assuming, in writing, Landlord's obligations under the Master Lease,
this Sublease, and the attached Consent.

     11. Collocation. Landlord and Sublandlord acknowledge that Subtenant's
business to be conducted in the Building requires the installation in the
Building of certain communications equipment by certain licensees and customers
of Subtenant (collectively, "Customers") in order for such Customers to
interconnect with the Equipment or to permit Subtenant to manage or operate such
Customers' equipment, or otherwise as may be required pursuant to applicable
statutes and regulations. Notwithstanding anything to the contrary contained in
Section 16 of the Master Lease, Landlord and Sublandlord hereby consent in
advance to any sublease, license agreement, "collocation agreement" or similar
agreement (collectively, "Customer License") between Subtenant and such a
Customer for the limited purpose of permitting such arrangements as described
above. The


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effectiveness of such advance consent to a particular Customer License is
conditioned upon (a) such Customer and Subtenant signing and submitting to
Sublandlord and Landlord a Notice and Agreement, in the form attached hereto as
Exhibit "E" to this Sublease, and (b) such Customer License being in writing and
consistent with the provisions of this Sublease (although Subtenant will only be
required to provide Sublandlord and Landlord a copy of the executed Customer
License if the Sublandlord or Landlord requests it in writing).

     12. Confidentiality. Landlord and Sublandlord shall keep all Confidential
Information of Subtenant confidential; provided nothing herein shall prevent
reasonable disclosure to attorneys, accountants, or business consultants, or
disclosure required by law, court order, or subpoena. For the purposes of this
Sublease, "Confidential Information" includes any data or information pertaining
to Subtenant or Subtenant's business, regardless of medium, that is provided by
Subtenant to Sublandlord or Landlord, including Subtenant's plans and
specifications or electrical power requirements, site plans, or copies of any
such information, but excludes any information (a) approved in writing by
Subtenant for release to third parties, (b) that Sublandlord or Landlord
possesses independently of Subtenant, or (c) that Subtenant places in the public
domain.

     13. Approvals; Utilization of Equipment and Subleased Premises. Subtenant's
obligations under this Sublease are conditioned upon Subtenant, within ninety
(90) days after the date Subtenant signs the Sublease, (1) obtaining all
licenses, permits or other governmental approvals as may be required for
Subtenant's proposed use of the Subleased Premises (the "Approvals") and (2)
determining to Subtenant's satisfaction, based on Subtenant's independent
investigation, that Subtenant will be able to utilize the Equipment and
Subleased Premises in the manner permitted under the Sublease. In the event
Subtenant determines in its sole discretion that it is unable to obtain any such
Approvals or utilize the Equipment and Subleased Premises as set forth above,
Subtenant may terminate this Sublease upon written notice to Sublandlord, in
which event the parties' obligations under this Sublease shall terminate,
effective as of the termination of the Sublease. In the event Subtenant does not
so terminate this Sublease within such 90-day period, Subtenant will be deemed
to have waived its termination right.


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     14. Master Lease. Except as otherwise expressly provided in this Sublease,
the covenants, agreements, terms, provisions and conditions of the Master Lease,
all as they relate to the Subleased Premises and are not inconsistent with the
terms of this Sublease, are made a part of and incorporated into this Sublease
as if recited herein in full, and the rights and obligations of the Landlord and
the Tenant under the Master Lease shall be deemed the rights and obligations of
Sublandlord and Subtenant, respectively, hereunder and shall be binding upon and
inure to the benefit of Sublandlord and Subtenant, respectively. In the event of
a conflict between the terms of the Master Lease and the terms of this Sublease,
the terms of this Sublease shall control. All references to the default of
Subtenant shall refer to the definition of default and shall including the cure
periods, grace periods and notice requirements set forth in the Master Lease.

     15. Performance Under Master Lease.

         15.1 Sublandlord's Performance.

               (a) Any obligation of Sublandlord regarding Subtenant's use or
occupancy of the Subleased Premises which is contained in this Sublease may be
performed by Sublandlord using reasonable efforts to cause the Landlord to
perform the same. Sublandlord shall have no obligation to commence any action or
incur any expense in order to cause such performance by the Landlord; provided,
however, that on Subtenant's request and at Subtenant's cost, Sublandlord shall
commence any action or take any steps deemed by Subtenant to be reasonably
necessary to enforce Subtenant's rights. If any cash recovery from such action
would be paid to Sublandlord, Subtenant shall first receive reimbursement of its
actual out-of-pocket costs. Thereafter, any recovery shall be allocated between
Sublandlord and Subtenant in proportion to their respective premises.

               (b) Landlord's Compliance. In light of the extremely sensitive
nature of Subtenant's Equipment and business operations, Landlord agrees that,
notwithstanding the fact that this is a Sublease, Subtenant shall have the right
to initiate a direct relationship with Landlord as deemed reasonably necessary
by Subtenant if Landlord is not in compliance with the terms of the Master Lease
or this Sublease, and such noncompliance results in an adverse effect on
Subtenant's Equipment or operations.



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         15.2 Landlord Consent. Whenever the consent of Landlord shall be
required under the Master Lease, Sublandlord agrees to use reasonable efforts to
obtain such consent. Subtenant shall pay all of Sublandlord's out-of-pocket
costs and expenses in connection with obtaining such consent as the same are
incurred.

         15.3 Master Lease Effective. Landlord and Sublandlord represent and
warrant to Subtenant that the Master Lease is in full force and effect, all
obligations of both Landlord and Sublandlord thereunder have been satisfied to
date and Sublandlord has neither given nor received a notice of default pursuant
to the Master Lease for an event which has not been fully cured.

         15.4 Sublandlord Covenants. Sublandlord covenants as follows: (i) not
to voluntarily terminate the Master Lease (except upon terms pursuant to which
the Landlord would recognize this Sublease as a direct lease upon all the terms
contained herein), (ii) to perform or cause to be performed those obligations of
Sublandlord under and otherwise to comply with all provisions of the Master
Lease that do not pertain to the Subleased Premises, (iii) to perform or cause
to be performed those obligations of Sublandlord under and otherwise comply with
all provisions of the Master Lease that pertain to the Subleased Premises and by
the terms of this Sublease are expressly not required to be performed by
Subtenant, including, without limitation, the obligation to pay rent and
additional rent as and when due (iv) not to modify the Master Lease so as to
adversely affect Subtenant's rights hereunder, and (v) to take all actions
reasonably necessary to preserve the Master Lease. Sublandlord covenants and
agrees with Subtenant that upon Subtenant paying the rent required under this
Sublease and paying all other charges and performing all of the covenants and
provisions on Subtenant's part to be observed and performed under this Sublease,
Subtenant shall and may peaceably and quietly have, hold and enjoy the Subleased
Premises.

         15.5 Subtenant's Rights. If Sublandlord does not pay rent as required
by the Master Lease or takes or fails to take an action which act or failure to
act directly and materially affects Subtenant's quiet enjoyment under its
Sublease, and there are less than ten (10) days remaining on any applicable cure
period under the Master Lease, then, Subtenant may, but shall not be obligated
to, (a) enter into a direct lease with Landlord pursuant to Section 15.6 below;
or (b) perform or


<PAGE>   14


cure such defaults on behalf of Sublandlord. If Subtenant elects option (b),
Sublandlord shall reimburse Subtenant for the actual out-of-pocket costs and
expenses incurred by Subtenant in performing such obligation or curing such
default along with interest on such amounts at the lesser of ten percent (10%)
per annum or the maximum legal rate then allowable by law from the date that
such sums are expended by Subtenant (the "Default Reimbursement").
Notwithstanding anything to the contrary in this Sublease, if the Default
Reimbursement is not paid in full within ten (10) days of a written request for
payment by Subtenant and provided Sublandlord has not notified Subtenant in
writing that it is, in good faith, contesting the costs incurred by Subtenant in
curing such default or performing such obligation, Subtenant may offset the
amount of the Default Reimbursement against rental amounts next owing hereunder.

         15.6 Termination of Master Lease. In the event of the threatened
cancellation or termination of the Master Lease for any reason whatsoever or of
the involuntary surrender of the Master Lease by operation of law prior to the
expiration date of this Sublease, Landlord and Subtenant shall enter into a
direct lease for the Subleased Premises for the balance of the term of this
Sublease and upon the terms hereof, but providing that Landlord shall have no
duty to maintain the Subleased Premises except as provided in Section 7.1 of the
Master Lease, and providing further that Landlord, at Landlord's sole election,
can require that Subtenant perform the maintenance obligations set out in
Section 7.1(i)(b), in which event Landlord shall reimburse Subtenant for the
reasonable costs of such maintenance. The direct lease shall be evidenced by an
agreement in form and substance reasonably satisfactory to the Landlord and
Subtenant. Landlord and Subtenant shall each execute and deliver the direct
lease within ten (10) business days after the cancellation or termination of the
Master Lease, and Landlord and Subtenant each waive the provisions of any law
now or hereafter in effect which may give either party the right of election to
surrender or require surrender of possession of the Subleased Premises as a
result of such cancellation or termination of the Master Lease. The execution of
a direct lease does not waive any claims Landlord and Subtenant may have against
Sublandlord for breach of the Lease or this Sublease.

         15.7 Direct Lease. At Subtenant's request, Sublandlord shall cooperate
with Subtenant in seeking a termination of the Master Lease with respect to the
Subleased


<PAGE>   15

Premises and replacement with a direct lease with the Landlord upon terms
acceptable to Subtenant in its sole discretion. Nothing herein shall obligate
Landlord to enter into such a direct lease, except on the terms set forth in
Section 15.6 above.

     16. Commissions. Subtenant warrants (i) that it had no dealing with any
real estate broker or agent in connection with the negotiation of this Sublease,
except for The Staubach Company ("Staubach"), whose commission Subtenant shall
pay in accordance with a separate agreement with Staubach, and (ii) that it
knows of no other real estate broker or agent who is or might be entitled to a
commission in connection with this Sublease. Sublandlord warrants that (i) it
had no dealing with any real estate broker or agent in connection with the
negotiation of this Sublease; and (ii) that it knows of no other real estate
broker or agent other than Staubach who is or might be entitled to a commission
in connection with this Sublease. Subtenant agrees to indemnify, hold and save
Sublandlord and Landlord harmless from and against any and all claims for
brokerage commissions or finders' fees payable to Staubach pursuant to the
aforementioned agreements. The provisions of this Section 16 shall survive the
expiration or earlier termination of this Sublease.

     17. Notices. Any notice which may or shall be given by either party
hereunder shall be either delivered personally or sent by certified mail, return
receipt requested or by nationally recognized overnight courier, addressed as
follows:

     Subtenant:          GTE Intelligent Network Services Incorporated
                         c/o Staubach Portfolio Services
                         6750 LBJ Freeway, Suite 1100
                         Dallas, Texas 75240
                         Attn:  Lease Administrator

     With a copy to:     GTE-BAS Service Supervisor
                         William Briley
                         500 East Carpenter Freeway
                         MC -TXD 1911C
                         Irving, Texas 75062


<PAGE>   16


     Sublandlord:        Jose G. Chavez
                         President
                         Micro-Media Solutions, Inc.
                         501 Waller
                         Austin, TX 78702

     With a copy to:     Mitchell Kettrick
                         Vice-President
                         Micro-Media Solutions, Inc.
                         501 Waller
                         Austin, TX 78702

or to such other address as may have been designated in a notice given in
accordance with the provisions of this Section 17. Any notice delivered by
overnight courier as aforesaid shall be deemed delivered one day after such
notice is deposited with such courier.

     18. Tenant Improvements. Sublandlord shall deliver the Subleased Premises
to Subtenant in their "as is" condition, with all moveable furniture removed and
in broom clean condition. Subtenant shall, at its sole cost and expense,
construct and build out the Subleased Premises. Subtenant shall conduct its own
bidding process and shall use its selected construction manager to coordinate
and manage the demolition and construction process. Subtenant's construction
shall be made in accordance with plans and specifications prepared by Subtenant
and approved by Sublandlord and Landlord, and in accordance with all applicable
building codes. Subtenant shall provide the final plans and specifications to
Sublandlord and Landlord prior to the commencement of demolition and
construction. Sublandlord and Landlord shall approve (or disapprove) such plans
and specifications within 3 business days of receipt, and approval shall not be
unreasonably withheld. Subtenant may, from time to time, make minor
modifications to the plans and specifications without the need to notify
Sublandlord or Landlord. Subtenant shall notify Sublandlord and Landlord of
material modifications to the plans and specifications throughout the
construction process. Sublandlord and Landlord shall approve (or disapprove)
such modifications within three business days of receipt, and approval shall not
be unreasonably withheld. Material modifications are modifications that affect
Building systems or the structural integrity of the Building. Subtenant shall
have the right, at is sole cost and expense, to install and maintain its own
security system in the Subleased Premises. Sublandlord


<PAGE>   17

and Landlord will not charge Subtenant a fee for reviewing Subtenant's plans for
the construction of the Subleased Premises, and will not charge a construction
management service fee. In addition, there will not be any charge for freight or
passenger elevator use or hoists, electricity, water, air conditioning or other
utilities (during generally accepted business hours) during the construction
(including move in) period of the Subleased Premises. Subtenant shall keep the
Subleased Premises and the Project free and clear of all liens.

     19. Parking. During the term of this Sublease, Sublandlord shall provide to
Subtenant, at no charge, at least one parking space for use by Subtenant's
employees, contractors, and visitors.

     20. Insurance.

         (a) Subtenant shall cause Sublandlord and the Landlord to be named as
additional insureds on its liability insurance policies and to furnish a
certificate of such coverage to Sublandlord, with a copy to Landlord. The amount
of the insurance shall be Three Million Dollars ($3,000,000.00). Except for
general public liability insurance, each such insurance policy carried by either
Sublandlord or Subtenant shall include such a waiver of the insurer's rights of
subrogation against the other parties and Landlord. Subtenant shall deliver a
certificate of insurance to Sublandlord within thirty (30) days after delivery
of possession of the Subleased Premises. Notwithstanding Section 8.4 of the
Master Lease, Subtenant shall be obligated to deliver certificates of insurance
as soon as possible, but not later than thirty (30) days after a scheduled
expiration date. In no event shall Subtenant allow its insurance to lapse or
expire.

         (b) Anything in this Sublease to the contrary notwithstanding,
Landlord, Sublandlord and Subtenant hereby waive any and all rights or recovery,
claim, action or cause of action against the others, their respective agents,
officers, employees and shareholders, for any loss or damage that may occur to
the Subleased Premises, the Premises, the Building or the Project, or any
improvements thereto or contents thereof, by reason of fire, the elements or any
other cause which could be insured against under the terms of standard fire and
extended coverage insurance


<PAGE>   18

policies, regardless of cause or origin [including negligence of such parties,
their agents, officers and employees,] [THIS IS BEING REVIEWED BY COUNSEL AND IS
OPEN.]

     21. Indemnity. Subtenant hereby agrees to defend, indemnify and hold
Sublandlord and Landlord harmless from and against any and all claims, losses
and damages, including, without limitation, reasonable attorneys' fees and
disbursements, which may at any time be asserted (a) against Sublandlord by the
Landlord for failure of Subtenant to perform any of the covenants, agreements,
terms, provisions or conditions contained in the Master Lease which by reason of
the provisions of this Sublease Subtenant is obligated to perform, or (b)
against Sublandlord and/or Landlord by any person by reason of Subtenant's use
and/or occupancy of the Subleased Premises. Sublandlord hereby agrees to defend,
indemnify and hold Subtenant harmless from and against any and all claims,
losses and damages, including, without limitation, reasonable attorneys' fees
and disbursements, arising out of or relating to (i) Sublandlord's failure to
perform its covenants, agreements and obligations hereunder, (ii) Sublandlord's
default in the payment of rent as required by the Master Lease, or (iii)
Sublandlord's action or failure to take an action which is a breach of the
Master Lease which directly and materially affects Subtenant's quiet enjoyment
under its Sublease. The provisions of this Section 21 shall survive the
expiration or earlier termination of the Master Lease or this Sublease.

     22. Severability. If any term or provision of this Sublease or the
application thereof to any person or circumstances shall, to any extent, be
invalid and unenforceable, the remainder of this Sublease or the application of
such term or provision to persons or circumstances other than those as to which
it is held invalid or unenforceable, shall not be affected thereby and each term
or provision of this Sublease shall be valid and be enforced to the fullest
extent permitted by law.

     23. Entire Agreement; Waiver. This Sublease contains the entire agreement
between the parties hereto and shall be binding upon and inure, to the benefit
of their respective heirs, representatives, successors and permitted assigns.
Any agreement hereinafter made shall be ineffective to change, modify, waive,
release, discharge, terminate or effect an abandonment hereof, in whole or in
part, unless such agreement is in writing and signed by the parties hereto,
including Landlord.


<PAGE>   19

     24. Captions and Definitions. Captions to the Sections in this Sublease are
included for convenience only and are not intended and shall not be deemed to
modify or explain any of the terms of this Sublease. Capitalized terms not
otherwise defined herein shall have the meaning ascribed to them in the Master
Lease.

     25. Further Assurances. The parties hereto agree that each of them, upon
the request of the other party, shall execute and deliver, in recordable form if
necessary, such further documents, instruments or agreements and shall take such
further action that may be necessary or appropriate to effectuate the purposes
of this Sublease. Subtenant agrees to provide to Landlord promptly following
request by Landlord, Estoppel Certificates meeting the requirements of Section
17 of the Master Lease, in the same fashion as Sublandlord has agreed therein to
provide Estoppel Certificates to Landlord.

     26. Governing Law. This Sublease shall be governed by and in all respects
construed in accordance with the internal laws of the State of Texas.

     27. Exhibits. Exhibits A, B, C, D, E, and F attached hereto are hereby made
a part hereof.

     28. Consent of Landlord. The validity of this Sublease shall be subject to
the Landlord's prior written consent hereto pursuant to the terms of the Master
Lease, and if Landlord's consent shall not be obtained and a copy thereof
delivered to Sublandlord and Subtenant within fifteen (15) days of the date
hereof, Subtenant shall have the option to cancel this Sublease by notice to
Sublandlord within thirty (30) days from the date hereof.

     Executed on the date first above written.

                         Sublandlord:

                         Micro-Media Solutions, Inc.,
                         a Texas corporation


                         By: /s/ Jose G. Chavez
                                 Jose G. Chavez
                         Title: President

                         By:/s/ Mitchell Kettrick
                         Title: Secretary or Treasurer


                         Subtenant:

                         GTE INTELLIGENT NETWORK SERVICES
                         INCORPORATED, a Delaware corporation

                         By: /s/ Ronald W. Kuypinski
                                 Ronald W. Kuypinski
                         Title: Vice-president, Corporate Real Estate


                         By:
                         Title:


<PAGE>   20

                                     CONSENT


          1. Consent to Sublease. Landlord hereby consents to the foregoing
Sublease for purposes of Section 11 of the Master Lease, and specifically agrees
to comply with the terms of those paragraphs of the Sublease that require
performance by Landlord.

          2. Options to Extend.

               2.1 Landlord further agrees to grant to Subtenant the option to
enter into a direct lease with Landlord upon termination of the Sublease in 2008
upon the following terms and conditions. Regardless of whether Sublandlord
exercises its option to renew the Master Lease pursuant to Section 6 of the
Second Addendum, Subtenant's option to enter into a direct lease with Landlord
shall commence in 2008, at the expiration of the initial term of the Master
Lease, as defined in the Second Addendum. Sublandlord's right to renew the
Master Lease shall not include the Subleased Premises if Subtenant elects to
enter


<PAGE>   21


into a direct lease with Landlord for the Subleased Premises. Provided Subtenant
is not in monetary default hereunder beyond any applicable notice and cure
periods, Subtenant shall have two five-year options (each, an "Option"), at the
rental amount described in Section 2.2 below, to lease directly from Landlord
all of the Subleased Premises. In order to exercise an Option, Subtenant shall
give Landlord written notice not later than 180 days prior to the termination
date of this Sublease (and of the termination of the first Option term) of its
intent to exercise the Option. If Subtenant exercises the Option for the first
Option period, the Base Rent shall be the scheduled rent for the last year under
Master Lease, increased by 3%, and the Base Rent shall increase by 3% each year
of the Option period. If Subtenant exercises the Option for the second Option
period, the Base Rent shall continue to increase by 3% per year. In addition to
Base Rent, Subtenant shall pay its proportionate share (27.70%) of annual
increases in Property Taxes for the Subleased Premises, over a base year of
1998; provided, however, that Subtenant shall not be obligated to pay increases
that exceed a 10% increase per year. Landlord shall pay any increases in excess
of 10% per year.

               2.2 If Subtenant does not exercise the first Option, it shall
have no right to exercise the second Option.

               2.3 Except for the term and rental rate, the direct lease shall
be on the same terms and conditions as this Sublease, including the
incorporation of those terms of the Master Lease that are not inconsistent with
the terms of the Sublease.

          3. Non-Disturbance/Subordination. Landlord hereby represents and
warrants that neither the Project nor the Subleased Premises is currently
subject to any mortgage or deed of trust. Subject to the requirement of the
Nondisturbance Agreement set forth below, this Sublease shall be subject and
subordinate to any mortgages or deeds of trust that may hereafter be placed
against the Subleased Premises by Landlord and to any advances thereunder and to
any interest thereon, and all renewals, replacements, and extensions thereof.
Provided, however, that any mortgagee or trustee may elect by written
notification to give the rights and interests of Subtenant under this Sublease
priority over the lien of its mortgage or deed of trust. The subordination of
this Sublease to any future mortgages or deeds of trust is expressly conditioned
upon


<PAGE>   22

Subtenant receiving from such mortgagee or holder of the lien of the deed of
trust an agreement (the "Nondisturbance Agreement") pursuant to which such party
agrees that the possession of the Subtenant under this Sublease shall not be
disturbed, so long as Subtenant is not in default under this Sublease beyond any
applicable cure period permitted under the Sublease or Master Lease. The
Nondisturbance Agreement may be on such form and contain such other commercially
reasonable terms as mortgagees or lienholders typically require in the ordinary
course of business.

          4. Improvements to Building.

               4.1 Building Improvements. Subtenant shall have the right, at its
sole cost and expense, to make the following improvements outside of the
Subleased Premises, and within the Building (the "Building Improvements").
Subtenant shall conduct its own building process and shall use its selected
contractor and subcontractors to construct the Building Improvements. The
Building Improvements shall be constructed in accordance with plans and
specifications prepared by Subtenant and approved by Landlord, and in accordance
with all applicable building codes. Subtenant shall provide the final plans and
specifications to Landlord prior to commencement of construction of the Building
Improvements. Landlord shall approve (or disapprove) such plans and
specifications within 3 business days of receipt, and approval shall not be
unreasonably withheld. Subtenant may, from time to time, make minor
modifications to the plans and specifications without the need to notify
Landlord. Subtenant shall notify Landlord of material modifications to the plans
and specifications or drawings throughout the construction process for the
Building Improvements. Landlord shall approve (or disapprove) such modifications
within three business days of receipt, and approval shall not be unreasonably
withheld. Material modifications are modifications that affect Building systems
or the structural integrity of the Building. Landlord will not charge Subtenant
a fee for reviewing Subtenant's plans for the construction of the Building
Improvements, and will not charge a construction management fee.

               4.2 Construction Details. The Building Improvements may include
the following items, which are hereby approved in concept by Landlord. The plans
and specifications or other drawings showing the details of these Building
Improvements shall be delivered to Landlord for approval (as described in
Paragraph 4.1 of this Consent) after the execution of this Sublease and Consent,
but prior to the commencement of construction.


<PAGE>   23

                    (a) Subtenant may connect the dry pipe fire protection
system (including the valve, header, compressor, and piping from the header) to
the Subleased Premises. The header and compressor may be placed in a new valve
closet which may be constructed by Subtenant and located adjacent to the
existing building fire sprinkler riser at the northeast corner of the Building.
The valve, header, compressor, and piping shall be located outside of the
Subleased Premises and within or around the Building and Project.

                    (b) Subtenant may tap off of the existing plumbing located
in the restrooms to provide small quantities of water (estimated to be less than
one gallon per day) to the Subleased Premises, the cost of which is deemed to be
included in the Base Rent.

                    (c) Subtenant may run condenser drain line(s) from the HVAC
condenser to the floor drain located in the restrooms.

                    (d) Subtenant may install normal, standby, and emergency
exhaust fans (for a total of three fans) for the battery room. For ease of
maintenance, the fans will be placed high in the ceiling space in the hall
outside the battery room and outside of the Subleased Premises.

                    (e) Subtenant may install an electrical power conduit that
runs from the power service entrance to the Subleased Premises.

                    (f) Subtenant may install a telephone conduit that runs from
the telephone service entrance to the Subleased Premises.

                    (g) Subtenant may install a lightning protection system,
including installation of lightning protection down conductors in ten (10)
locations throughout the Building, at locations to be determined by Subtenant
and reasonably approved by Landlord.

                    (h) Subtenant may install fiber-optic conduits at locations
to be determined by Subtenant, and reasonably approved by Landlord.

                              LANDLORD:

                              WBH, Ltd.,
                              a Texas Limited Partnership

                              By: /s/ Will Houston
                              Title: President

                              By: /s/
                              Title: Boardmember


<PAGE>   24

     EXHIBIT "C"

     EQUIPMENT LIST

<TABLE>
<CAPTION>
                         M POP to 1600 SF

<S>                      <C>                          <C>  
          2 ea.     -     Generator                    230KW
          2 ea.     -     20 ton Liebert
          2 ea.     -     Fan Coils
          2 ea.     -     Generator ATS
          1 ea.     -     2000 AMP DC System
</TABLE>

Note - All generators will require either a propane, diesel or natural gas fuel
system.

     EXHIBIT "D"

     ELECTRICAL REQUIREMENTS

     M POP to 1600
     SF 207KW (90% of Generator Capability)


     EXHIBIT "E"

     COLLOCATION AGREEMENT NOTICE AND AGREEMENT


TO:                         FROM:

Landlord                    GTE Intelligent  
                                            ---------------------------
Sublandlord                 Network Services 
                                              -------------------------
(Collectively,              Incorporated          ("Lessee's Customer")
Landlord and                ("Lessee")
Sublandlord are
referred to herein as
"Lessor")

LOCATION:                   501 Waller, Austin, Texas
DATE:                       
                            -------------------------------------

     RECITALS

     This Notice and Agreement is hereby given to Lessor by Lessee and Lessee's
Customer. Lessor and Lessee are the current parties to a Sublease dated        ,
as amended to date (the "Master Sublease"), concerning certain "Subleased
Premises" (as defined in the Master Sublease) in Lessor's building at 501
Waller, Austin, Texas (the "Building"). Landlord is the master landlord under
the Master Lease referred to in the Master Sublease. Lessee's Customer,
concurrently herewith, is entering into a written agreement with Lessee calling
for Lessee's Customer to have limited rights of access to and use of certain
equipment space (the "Equipment Space") in the Subleased Premises for the
installation and operation of equipment of Lessee's Customer. Such equipment
will be connected with the telecommunications system of Lessee. Regardless of
whether such written agreement is called by Lessee and Lessee's Customer a
sublease, a license, or a collocation agreement, or is called by

<PAGE>   25

some other name, it is referred to herein as the "License". The Equipment Space
is more specifically described in the License. As more specifically described in
the Master Sublease, this Notice and Agreement is given to satisfy the
conditions to the effectiveness of Lessors' advance consent in the Master
Sublease to transactions such as this one.

     Therefore, in consideration of their mutual covenants in this Consent,
Lessee and Lessee's Customer agree as follows for the benefit of Lessor:

     SPECIFIC TERMS

     1. Form of License. Lessee agrees to provide a redacted copy of the License
to Lessor if Lessor so requests in writing.

     2. Master Sublease. Lessee and Lessee's Customer agree that the Master
Sublease is and shall remain in all respects prior and superior to the License
and is not being modified by the License. Lessor is not joining in nor bound by
any agreement, representation or warranty contained in the License. Any matter
that requires Lessor's approval under the Master Sublease shall continue to
require such approval. Lessee's Customer shall obtain directly from Lessee any
copies Lessee's customer requires of the applicable terms of the Master
Sublease, and Lessor shall have no obligation in that regard. Upon any
termination of the Master Sublease, whether due to agreement, default or
expiration of the term, Lessee's Customer shall immediately surrender possession
of the Subleased Premises, including the Equipment Space, to Lessor.

     3. Scope of Lessor's Consent. Lessor's advance consent shall not constitute
or be construed as a consent to any other sublease, assignment, hypothecation,
conveyance of any nature, license, collocation agreement or other agreement for
use or occupancy of any portion of the Subleased Premises, except as provided in
the Master Sublease.

     4. Additional Agreements by Lessee's Customer. Lessee's Customer agrees to
use the Equipment Space only for the limited purposes described in the Recitals
above, and to comply with all Lessor's Building Rules in effect from time to
time of which Lessee's Customer has notice. Similarly, Lessee's Customer agrees
not to violate any provisions of the Master Sublease. Without limiting the
foregoing, Lessee's Customer agrees


<PAGE>   26

immediately to repair any damage to the Subleased Premises or Building caused by
the installation, operation, maintenance or removal of the equipment of Lessee's
Customer.

     Lessee's Customer hereby waives on behalf of itself, and agrees to defend,
indemnify and hold harmless Lessor, and their respective officers, directors,
shareholders, agents and employees (collectively, the "Lessor Group") from and
against, any and all claims, actions, losses, expenses, and liabilities
(collectively, "Claims") arising from or related in any way to the presence in
or about the Subleased Premises or the Building (or use of the Subleased
Premises or the Building) by Lessee's Customer or its employees, contractors,
guests or invitees (including but not limited to Claims for bodily injury,
Project damage, loss of data, or interruptions in service), arising out of any
negligence of Lessee's Customer. Such waiver and indemnity agreement by Lessee's
Customer shall not apply to Claims to the extent arising out of the negligence,
wilful misconduct or breach of this Agreement by Lessor.

     Lessee's Customer shall maintain throughout the License term liability
insurance with a combined single limit of at least $1,000,000 covering the
activities of Lessee's Customer in and about the Building. Such insurance shall
be issued by a carrier duly licensed in the State of Texas and having a rating
of B + or better in Best's Insurance Guide. Such insurance shall include an
endorsement naming Lessor as an additional insured with respect to any incidents
in or about the Building and shall not be cancelable without at least 30 days'
prior written notice to Lessor. Lessee's Customer shall provide to Lessor
evidence reasonably acceptable to Lessor of such insurance coverage.

     5. Miscellaneous. This Notice and Agreement supersedes all prior oral and
written offers or agreements between the parties with respect to its subject
matter. This Notice and Agreement is part of and shall be attached to the Master
Sublease. The Master Sublease may be amended only in a writing signed by Lessor
and Lessee. All terms of the existing Master Sublease not expressly affected or
altered by this Notice and Agreement remain in full force.

     IN WITNESS WHEREOF, this Notice and Agreement has been duly executed by the
parties as of the date first above written.


<PAGE>   27


LESSEE:                              LESSEE'S CUSTOMER:

GTE Intelligent Network
Services Incorporated,
a Delaware corporation

By:                                   By:
its                                   its

By:                                   By:
its                                   its

ACCEPTED AND AGREED:

LESSOR:                              LESSOR:

LANDLORD:                            SUBLANDLORD:
WBH, Ltd.,                           Micro-Media Solutions, Inc.,
a Texas limited partnership          a Texas corporation

By:                                  By:
its                                  its

By:                                  By:
its                                  its


     EXHIBIT F

     RENTS FOR INITIAL TERM

<TABLE>
<CAPTION>
SUBLEASE             BASE RENT    ANNUAL     BASE RENT
YEAR      RENT/SF    PER MONTH   INCREASE     PER YEAR

<S>        <C>        <C>            <C>     <C>      
1          3.75       3,125.00       0       37,500.00
2          3.86       3,218.75       3%      38,625.00
3          3.98       3,315.31       3%      39,783.75
4          4.10       3,414.77       3%      40,977.26
5          4.22       3,517.22       3%      42,206.58
6          4.35       3,622.73       3%      43,472.78
7          4.48       3,731.41       3%      44,776.96
8          4.61       3,843.36       3%      46,120.27
9          4.75       3,958.66       3%      47,503.88
10         4.89       4,077.42       3%      48,928.99
</TABLE>