<PAGE>   1
                                  Exhibit 10.33

AT&T

                          AT&T Master Carrier Agreement

<TABLE>
<S>                                     <C>                                     <C>
CUSTOMER Name (Full Legal Name):                                                AT&T Sales Representative:
Universal Access, Inc                   AT&T Corp.,                             Doug Marshall
                   ("CUSTOMER")              a New York corporation ("AT&T")

CUSTOMER Name (and Title) for Notice:   AT&T Name (and Title) for Notice:       AT&T Contact Telephone Number:
                   Pam Whitehead        Carol Hawkins                           314 275 3086

CUSTOMER Address:                       AT&T Address:                           Initial Deposit Amount Required:
100 N. Riverside Plaza                  300 Atrium Drive                        [***]
Suite 2200                              Room 3W101

City          State       Zip Code      City       State      Zip Code
Chicago       IL          60606         Somerset   NJ         08873

CUSTOMER Fax number for Notice:         AT&T Fax number for Notice:
312 660 5050                            732 805 5727
</TABLE>

This Master Carrier Agreement shall be legally binding when signed by both
parties and shall continue in effect until the end of the longest term specified
in the Attachment(s), or until otherwise terminated as provided in accordance
with this Agreement. The rates and commitments provided in the Attachments shall
be effective as provided in each Attachment.

This Master Carrier Agreement consists of this Cover Sheet, the attached Terms
and Conditions, and the Attachment(s) listed below (these documents together are
collectively referred to as the "Agreement"). In the event of any inconsistency
between these documents, precedence will be given to the documents in the
following order: (1) this Cover Sheet; (2) Attachment(s); (3) the Terms and
Conditions. In the event of any inconsistency between the terms of this
Agreement and the terms of an applicable Tariff, the terms of the Agreement
shall prevail.

<TABLE>
<CAPTION>
TITLE                                                    Doc. ID             Date/time stamp
-----                                                    -------             ---------------
<S>                                                    <C>                   <C>
Master Carrier Agreement - Terms and Conditions        MCA 990816.doc        08/16/99 3:42 pm
Supplemental Terms and Conditions                      MCA_supp.doc          8/17/1999 11:02
                                                                                   AM
Data Service Terms and Pricing                         UAccess-D990902.doc   9/2/1999 10:55AM
</TABLE>

CUSTOMER'S SIGNATURE BELOW ACKNOWLEDGES THAT CUSTOMER HAS READ, UNDERSTANDS AND
AGREES TO EACH OF THE TERMS AND CONDITIONS OF THIS AGREEMENT AND THAT THE
INDIVIDUAL SIGNING THIS AGREEMENT IS DULY AUTHORIZED TO DO SO.

CUSTOMER                                     AT&T Corp.

By: /s/ ROBERT J. POMMER                     By: /s/ JAMES M. DOWNEY, JR.
    -------------------------------              -------------------------------
    (Authorized Customer Signature)             (Authorized AT&T Signature)


Robert J. Pommer                             James M. Downey, Jr.
-----------------------------------          -----------------------------------
(Typed or Printed Name and Title)            (Typed or Printed Name and Title)

Date: 9/27/99                                Date: 10/12/99
      -------                                      -----------------------------



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

Not for Publication - All Rights Reserved
<PAGE>   2

                MASTER CARRIER AGREEMENT - TERMS AND CONDITIONS           Page 1


1. PROVISION OF SERVICES. CUSTOMER hereby orders and AT&T hereby agrees to
provide the AT&T services described in the Attachment(s) to this Agreement (the
"Services"). Jurisdictionally intrastate services may be provided pursuant to an
Attachment to this Agreement, pursuant to applicable state tariffs, or as
otherwise permitted by applicable state law. AT&T is not responsible for the
quality of transmission or signaling on CUSTOMER's side of the network interface
between AT&T and CUSTOMER. Service is furnished subject to the availability of
the service components required, and subject to operational and systems
constraints.

2. BILLING AND PAYMENT FOR THE SERVICES. Except as may be provided in an
Attachment, AT&T will send a single monthly bill for each of the Services to one
location designated by CUSTOMER. CUSTOMER is liable for all amounts due to AT&T
under this Agreement. Payment is due upon presentation of a bill. Payment will
be considered timely if made to AT&T within thirty days after the bill date (for
voice services, the bill date is the day after the end of the usage period
covered by the bill; for data services, the bill date is the first day of the
service period covered by the bill). Any charges not paid to AT&T within such
period will be considered past due.

3. NON-PAYMENT. At AT&T's option, interest charges may be added to any past due
amounts at the lower of 12.0% per year or the maximum rate allowed by law.
CUSTOMER shall reimburse AT&T for reasonable attorney's fees and any other costs
associated with collecting delinquent or dishonored payments. Restrictive
endorsements or other statements on checks accepted by AT&T will not apply.

4. BILLING DISPUTES. If CUSTOMER wishes to dispute a charge on a bill, CUSTOMER
must identify the specific charge in dispute and provide a full written
explanation of the basis for the dispute using a standard AT&T billing dispute
form within 90 days after the bill date. CUSTOMER may withhold payment of a
charge subject to a good faith dispute provided: (a) CUSTOMER submits the
billing dispute, using a standard AT&T billing dispute form, before making
payment of the disputed charge; (b) CUSTOMER pays the undisputed portion of all
charges; and (c) CUSTOMER cooperates reasonably with AT&T's efforts to
investigate and resolve the dispute. If AT&T determines that a disputed charge
was billed in error, AT&T shall issue a credit to reverse the amount incorrectly
billed. If AT&T determines that a disputed charge was billed correctly, payment
shall be due from CUSTOMER within five days after AT&T advises CUSTOMER in
writing that the dispute is denied.

5. DEPOSITS. Using its Deposit standards, AT&T has assessed and CUSTOMER shall
pay the Initial Deposit amount specified on the Cover Sheet before Services are
provided. AT&T may require CUSTOMER, during the term of this Agreement, to
tender a deposit in an amount to be determined by AT&T in its reasonable
discretion. AT&T will rely upon commercially reasonable factors to determine the
need for and amount of any deposit. These factors may include, but are not
limited to, payment history, number of years in business, history of service
with AT&T, bankruptcy history, current account treatment status, financial
statement analysis, and commercial credit bureau rating, as well as commitment
levels and anticipated monthly charges. Any deposit will be held by AT&T as a
guarantee for the payment of charges (including but not limited to potential
shortfall charges). A deposit does not relieve CUSTOMER of the responsibility
for the prompt payment of bills. Interest (at the rate of 6% per year) will be
paid to CUSTOMER for any period that a cash deposit is held by AT&T. A failure
of CUSTOMER to post a deposit as required by AT&T pursuant to this paragraph
shall constitute a material breach of this Agreement by CUSTOMER.

6. OBLIGATIONS REGARDING TAXES. CUSTOMER shall pay any applicable local, state
and federal taxes, levied upon the sale, installation, use or provision of the
Services, except to the extent customer provides a valid tax exemption
certificate to AT&T prior to the delivery of Services. Gross Receipts Taxes will
be charged to CUSTOMER as provided in AT&T Tariff F.C.C. No. 1, Section 2.5.14,
as amended from time to time.

7. CUSTOMER IS A CARRIER. CUSTOMER certifies it is a "common carrier" as defined
in the Communications Act of 1934 (see sections 153(10) and 211), with all
required state and federal operating authority.

8. RESPONSIBILITIES OF CUSTOMER. CUSTOMER is responsible for interfacing and
communicating with its End Users, for placing any orders, and for assuring that
it and its Intermediate Resellers (if any) comply with the provisions of this
Agreement and with all applicable federal and state laws and regulatory
requirements with respect to the resale of Services provided under this
Agreement. CUSTOMER is responsible for arranging premises access at any
reasonable time so that AT&T personnel may install, repair, maintain, inspect or
remove service components.

9. ABUSE OF SERVICE. The abuse of Service is prohibited. Using Service or
permitting Service to be used in the following ways constitutes abuse: (a)
making calls that might reasonably be expected to frighten, abuse, torment, or
harass another; (b) carrying calls that originate on the network of a
facilities-based interexchange carrier other than AT&T and terminate
disproportionately to domestic locations for which AT&T's cost of terminating
switched access (based on the published access rates of the incumbent local
exchange companies) is above AT&T's price for the call under this Agreement
(after application of discounts); (c) interfering unreasonably with the use of
AT&T service by others or the operation of the AT&T network; (d) subjecting AT&T

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<PAGE>   3

                MASTER CARRIER AGREEMENT - TERMS AND CONDITIONS           Page 2


personnel or non-AT&T personnel to hazardous conditions; (e) transmitting any
message or code, locating a person, or otherwise giving or obtaining
information, without payment for the Services; or (f) attempting to avoid the
payment, in whole or in part, of any charges by any means or device (non-payment
of billed charges will not be considered abuse of service for purposes of this
Section). In any instance in which AT&T believes in good faith that there is
abuse of Service as set forth above, AT&T may immediately restrict, suspend or
discontinue providing Service, without liability on the part of AT&T, and then
notify CUSTOMER of the action that AT&T has taken and the reason for such
action. To the extent doing so does not interfere with its ability to prevent
abuse of Service (to be determined in AT&T's reasonable judgment), AT&T will
attempt to limit any restriction, suspension or discontinuance under this
Section to the locations, phone numbers, or Services with respect to which the
abuse is taking place.

10. DEFAULT. If a party breaches any material term of this Agreement and the
breach continues unremedied for 60 days after written notice of default, the
other party may terminate for cause any Attachment materially affected by the
breach. If CUSTOMER is in breach of its payment obligations (including failure
to pay a required deposit), and fails to make payment in full within 5 days
after receipt of written notice of default, AT&T may, at its option, terminate
the Agreement, terminate affected Attachments, suspend Service under the
affected Attachments, and/or require a deposit, advanced payment, or other
satisfactory assurances in connection with any or all Attachments as a condition
of continuing to provide Services; except that AT&T will not take any such
action as a result of CUSTOMER's non-payment of a charge subject to a timely
billing dispute, unless AT&T has reviewed the dispute and determined that the
charge is correct. An Attachment may be terminated by either party immediately
upon written notice if the other party has become insolvent or involved in a
liquidation or termination of its business, or adjudicated bankrupt, or been
involved in an assignment for the benefit of its creditors. CUSTOMER shall be
liable to AT&T for Termination Charges, as specified in a terminated Attachment,
in the event that AT&T terminates an Attachment as a result of a breach by
CUSTOMER. Termination by either party of an Attachment does not waive any other
rights or remedies it may have under this Agreement.

11. NO WARRANTIES. AT&T MAKES NO WARRANTIES, EXPRESS OR IMPLIED, UNDER THIS
AGREEMENT AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR A PARTICULAR PURPOSE. AT&T DOES NOT WARRANT THAT THE SERVICES WILL BE
UNINTERRUPTED OR ERROR-FREE, OR THAT THE SERVICES WILL MEET CUSTOMER'S
REQUIREMENTS OR THAT THE SERVICES WILL PREVENT UNAUTHORIZED ACCESS BY THIRD
PARTIES. AT&T DOES NOT AUTHORIZE ANYONE TO MAKE A WARRANTY OF ANY KIND ON ITS
BEHALF AND CUSTOMER SHOULD NOT RELY ON ANYONE MAKING SUCH STATEMENTS.

12. LIMITATION OF LIABILITY. THE LIABILITY OF AT&T ASSOCIATED WITH THE
INSTALLATION, PROVISION, USE, MAINTENANCE, REPAIR, TERMINATION OR RESTORATION OF
SERVICE PROVIDED PURSUANT TO THIS AGREEMENT SHALL NOT EXCEED AN AMOUNT EQUAL TO
THE INITIAL PERIOD CHARGE FOR AFFECTED CALLS (FOR CALLS SUBJECT TO MEASURED
CHARGES) OR THE CHARGES FOR AFFECTED SERVICE FOR THE PERIOD DURING WHICH THAT
SERVICE WAS AFFECTED (FOR ALL OTHER SERVICES). IN NO EVENT SHALL AT&T BE LIABLE
FOR: (A) ANY INDIRECT, INCIDENTAL, CONSEQUENTIAL, PUNITIVE, RELIANCE OR SPECIAL
DAMAGES, INCLUDING WITHOUT LIMITATION DAMAGES FOR LOST PROFITS, ADVANTAGE,
SAVINGS OR REVENUES OF ANY KIND, OR INCREASED COST OF OPERATIONS, WHETHER OR NOT
AT&T HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES; OR (B) ANY CLAIM OR
DAMAGES CAUSED BY OR ARISING OUT OF (i) ANY ACT OR OMISSION (INCLUDING WITHOUT
LIMITATION UNAUTHORIZED USE, THEFT, OR ALTERATION OF SERVICE, OR INTERFERENCE
WITH SERVICE) BY CUSTOMER, AN INTERMEDIATE RESELLER, AN END USER, OR ANOTHER
THIRD PARTY, (ii) SERVICE INTERRUPTIONS, OR (iii) INTEROPERABILITY, INTERACTION
OR INTERCONNECTION OF THE SERVICES PROVIDED UNDER THIS AGREEMENT WITH
APPLICATIONS, EQUIPMENT, SERVICES OR NETWORKS PROVIDED BY CUSTOMER OR THIRD
PARTIES. THE LIMITATIONS OF LIABILITY SET FORTH IN THIS AGREEMENT SHALL SURVIVE
FAILURE OF AN EXCLUSIVE REMEDY, AND SHALL APPLY REGARDLESS OF THE FORM OF
ACTION, WHETHER IN CONTRACT, TORT, WARRANTY, STRICT LIABILITY, OR NEGLIGENCE
(INCLUDING WITHOUT LIMITATION ACTIVE AND PASSIVE NEGLIGENCE).

13. FORCE MAJEURE. Neither party nor its Affiliates, subsidiaries, or
subcontractors shall be liable to the other party for any delay, failure in
performance, loss or damage due to force majeure conditions such as fire,
explosion, power blackout, earthquake, volcanic action, flood, hurricane, the
elements, strike, embargo, labor disputes, civil or military authority, war,
acts of God, acts or omissions of other carriers (except, for CUSTOMER, the acts
of omissions of its Intermediate Resellers), acts of regulatory or governmental
agencies, or other causes beyond their reasonable control, except that
CUSTOMER's obligation to pay for services provided

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<PAGE>   4

                MASTER CARRIER AGREEMENT - TERMS AND CONDITIONS           Page 3


shall not be excused. Changes in economic, business or competitive conditions
are not force majeure conditions. If CUSTOMER is unable to meet its commitments
as a direct result of a force majeure condition, CUSTOMER may suspend its
commitments for one full billing month (or longer, with AT&T's written consent,
which shall not be unreasonably withheld). The effect of such a suspension of
commitment will be to exclude the affected month(s) from all calculations
affecting the CUSTOMER's commitments and to extend the term of this Agreement by
the same number of months. CUSTOMER must provide notice to AT&T of the force
majeure condition giving rise to the right to suspend commitments within 30 days
after its occurrence.

14. INDEMNIFICATION. CUSTOMER shall indemnify, defend, and hold harmless AT&T
and its directors, officers, employees, agents, subsidiaries, affiliates,
successors and assigns from any and all claims, damages and expenses whatsoever
(including reasonable attorneys' fees) arising on account of or in connection
with CUSTOMER's use, resale or sharing of the Services provided under this
Agreement, including but not limited to: (a) claims for libel, slander, invasion
of privacy; (b) claims for infringement of copyright arising from any
communication; (c) claims arising from any failure, breakdown, interruption or
deterioration of service provided by AT&T to CUSTOMER or by CUSTOMER to End
Users or Intermediate Resellers; (d) claims arising from CUSTOMER's marketing
efforts, including but not limited to CUSTOMER's violation of laws and
regulations applicable to the authorization and proof of authorization necessary
to convert an End User to CUSTOMER's service; and (e) claims of patent
infringement arising from combining or using services or equipment furnished by
AT&T in connection with services or equipment furnished by others. AT&T shall
indemnify, defend, and hold harmless CUSTOMER and its directors, officers,
employees, agents, subsidiaries, affiliates, successors, and assigns from all
claims of patent infringement arising solely from the use of the Services.
CUSTOMER's indemnification obligations do not apply to claims for damages to
real or tangible personal property or for bodily injury or death negligently
caused by AT&T.

15. USE OF MARKS. Nothing in this Agreement creates in a party any rights in the
other party's trade names, trademarks, service marks or any other intellectual
property. Either party may use the other party's trade names, trademarks, or
service marks only to the extent such use is not prohibited by this Agreement
and is otherwise permitted by law (including but not limited to the Lanham Act).
In no event shall either party use or display, in advertising or otherwise, any
of the other party's logos, trade dress, trade devices or other indicia of
origin, or any confusingly similar logos, trade dress, trade devices or indicia
of origin. CUSTOMER will not conduct business under any AT&T corporate or trade
name, trademark, service mark, logo, trade dress, trade device, indicia of
origin or other symbol that serves to identify and distinguish AT&T from its
competitors, or under any confusingly similar corporate or trade name,
trademark, service mark, logo, trade dress, trade device, indicia of origin or
other symbol. CUSTOMER will not indicate or imply to any other party that
CUSTOMER is affiliated with AT&T, that CUSTOMER is authorized by AT&T to sell or
provide service to them, that CUSTOMER is providing (or will provide) service to
such party jointly or in collaboration or partnership with AT&T, or as the agent
of AT&T, or that service provided by CUSTOMER or another carrier is provided by
AT&T. Except to the limited extent (if any) as may be required under law,
neither CUSTOMER nor an Intermediate Reseller shall indicate or imply to any
existing or potential End User (or Intermediate Reseller) that any portion of
the service provided to the End User (or Intermediate Reseller) by CUSTOMER or
the Intermediate Reseller is provided by AT&T or is carried over the AT&T
network or AT&T facilities.

16. RELATIONSHIP OF THE PARTIES. The relationship between the parties shall be
that of independent contractors and not of principal and agent, employer and
employee, franchiser and franchisee, partners or joint venturers. This Agreement
does not establish CUSTOMER as a dealer, distributor or franchisee of AT&T, and
no fee is being paid to AT&T to enter into this Agreement.

17. ACKNOWLEDGMENT OF RIGHT TO COMPETE. Each party acknowledges that nothing in
this Agreement diminishes or restricts in any way the rights of the parties to
engage in competition with each other. Each party acknowledges that it remains
at all times solely responsible for the success and profits of its own business.

18. USE OF MARKETING INFORMATION. Either party may use for its own marketing
purposes any and all information that it lawfully obtains from sources other
than the other party, including but not limited to information that either party
may have as a result of the sale by that party of telecommunications services or
equipment to End Users.

19. CONFIDENTIAL INFORMATION DEFINED. "Confidential Information" consists of the
following: all information disclosed by one party or its agent or representative
(the "Disclosing Party") to the other party or its agent or representative (the
"Receiving Party") in connection with this Agreement regarding the
telecommunications needs of CUSTOMER and/or the telecommunications offerings of
AT&T, to the extent that (a) for information disclosed in written, graphic or
other tangible form, it is designated by appropriate markings to be confidential
or proprietary or (b) for information disclosed orally, it is both identified as
proprietary or confidential at the time of disclosure and

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                MASTER CARRIER AGREEMENT - TERMS AND CONDITIONS           Page 4


summarized in a writing so marked within 15 business days following the oral
disclosure. Notwithstanding the foregoing, all written or oral pricing,
contract, and tariff proposals exchanged between the parties shall be
Confidential Information, whether or not so designated. Confidential Information
is the property of the Disclosing Party and shall be returned to the Disclosing
Party upon request. This Agreement is Confidential Information as to which each
party is both a Disclosing Party and a Receiving Party. Information made known
to the public by the Disclosing Party or a third party, or previously known to
the Receiving Party free of any obligation to keep it confidential, or
independently developed by the Receiving Party, shall not be Confidential
Information.

20. CONFIDENTIALITY OBLIGATIONS. A Receiving Party shall hold all Confidential
Information in confidence from the time of disclosure until at least 2 years
following the termination of this Agreement. During that period, the Receiving
Party: (a) shall use such Confidential Information only for the purposes of
performing this Agreement and using the Services; (b) shall reproduce such
Confidential Information only to the extent necessary for such purposes; (c)
shall restrict disclosure of such Confidential Information to employees that
have a need to know for such purposes; (d) shall advise those employees of the
obligations of this Agreement; (e) shall not disclose Confidential Information
to any third party without prior written approval of the Disclosing Party except
as expressly provided in this Agreement; and (f) shall use at least the same
degree of care (in no-event less than reasonable care) as it uses with regard to
its own proprietary or confidential information to prevent the disclosure,
unauthorized use or publication of Confidential Information.

21. PUBLICITY. No public statements or announcements relating to this Agreement
shall be issued by either party without the prior written consent of the other
party.

22. ALTERNATIVE DISPUTE RESOLUTION. The parties will attempt to settle any claim
for non-payment of charges or recovery of overpayment of charges for the
Services provided under this Agreement (hereinafter a "Billing Dispute"),
through good faith negotiations. The parties may agree to submit a Billing
Dispute to non-binding mediation. At any time, the party seeking payment may
submit a notice of arbitration of a Billing Dispute for arbitration under the
United States Arbitration Act pursuant to the terms of this Section and the
Non-Administered Arbitration Rules of the CPR Institute for Dispute Resolution
("CPR"), to the extent such rules do not conflict. The Arbitration will be held
in New York, New York, or any other location selected by mutual agreement of the
parties. The arbitrator shall not have the power to award any damages in excess
of the limits set forth in or excluded under the limitations of liability
provided in this Agreement. The arbitrator may not limit, expand or otherwise
modify the terms of this Agreement. The arbitrator shall strictly limit
discovery to the production of documents directly relevant to the facts alleged
in the notices of arbitration and defense. If depositions are required, the
arbitrator shall permit each Party to conduct an equal number of depositions
(not to exceed five per side), with equal limits on the number of deposition
hours for each Party (not to exceed 7 per deposition). If an evidentiary hearing
is held, each Party's presentation of its case shall be limited to three (3)
days. Requests for temporary injunctive relief may be submitted to a court of
competent jurisdiction if the arbitrator has not yet been appointed, but the
arbitrator shall have the authority to modify any injunctive relief granted by
such a court. The arbitration award shall be made final within eight months of
filing of the notice of arbitration and judgment upon the award may be entered
in any court having competent jurisdiction. All participants and the arbitrator
shall hold the existence, content and results of mediation and arbitration in
confidence, except as necessary to enforce a final settlement agreement or to
enforce an arbitration award. Each party shall bear its own expenses and equally
share expenses related to the compensation of the arbitrator. The arbitrator's
award shall be in writing and shall state the reasons for the award.

23. TIME TO BRING CLAIMS. Any initial demand for arbitration pursuant to this
Agreement, and any legal action arising under this Agreement, must be initiated
within two years after the cause of action arises.

24. NOTICES. All notices under this Agreement shall be in writing and shall be
made: (a) by personal delivery; (b) by certified or registered mail, postage
prepaid return receipt requested, (c) by overnight delivery, or (d) by facsimile
transmission. Notice shall be sent to the individuals identified on the Cover
Sheet (at the address and/or fax number designated for notice), or to such other
individual, address or fax number as a party may designate by notice to the
other party.

25. EQUIPMENT. AT&T shall retain title to all of its equipment and facilities
used to provide service under this Agreement. CUSTOMER is liable to AT&T for the
replacement cost of any AT&T-provided equipment installed at CUSTOMER's premises
in the event of loss of said equipment for any reason, including but not limited
to theft.

26. EXPORT REGULATIONS. The parties acknowledge that any products, software, and
technical information (including, but not limited to, services and training)
provided under this Agreement are subject to U.S. export laws and regulations
and any use of or transfer of such products, software and technical information
must be authorized under those regulations. CUSTOMER agrees that it will not use
distribute, transfer or transmit the products, software or technical information
(even if incorporated into other products) except in compliance

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<PAGE>   6

                MASTER CARRIER AGREEMENT - TERMS AND CONDITIONS           Page 5


with U.S. export regulations. If requested by AT&T, CUSTOMER also agrees to sign
written assurances and other export-related documents as may be required for
AT&T to comply with U.S. export regulations.

27. QUALITY MONITORING. CUSTOMER authorizes AT&T to monitor and record calls to
AT&T concerning the Services for training and quality control purposes.

28. ASSIGNMENT. This Agreement may not be assigned by either party except that
either party may assign its rights or delegate its duties under this Agreement
to an Affiliate of that party.

29. NO THIRD PARTY BENEFICIARIES. This Agreement does not expressly or
implicitly provide any third party (including End Users) with any remedy, claim,
liability, reimbursement, cause of action or other right or privilege.

30. NON-WAIVER. The failure of a party to enforce any right under this Agreement
at any particular point in time shall not constitute a continuing waiver of any
such right with respect to the remaining term of this Agreement, or the waiver
of any other right under this Agreement.

31. SEVERABILITY. If any portion of this Agreement is found to be invalid or
unenforceable, the remaining provisions shall remain in effect and the parties
shall immediately begin negotiations to replace any invalid or unenforceable
portions that are essential parts of this Agreement.

32. SURVIVAL OF TERMS. The rights and obligations of either party that by their
nature would continue beyond the termination or expiration of this Agreement
shall survive termination or expiration of this Agreement. For example, the
provisions of this Agreement regarding Confidentiality shall remain in effect
for 2 years following termination of this Agreement and the provisions of this
Agreement regarding arbitration, indemnification, and/or limitation of liability
shall survive termination of this Agreement as to any cause of action arising
under the Agreement.

33. CHOICE OF LAW. The domestic law of the State of New York, except its
conflict-of-laws rules, shall govern the construction, interpretation, and
performance of this Agreement, except to the extent superceded by federal law.

34. AMENDMENT. No amendment, supplement, modification or waiver of any provision
of this Agreement shall be effective unless in writing and signed by authorized
representatives of both parties.

35. ENTIRE AGREEMENT. This Agreement constitutes the entire agreement between
the parties with respect to the Services. This Agreement supersedes all prior
agreements, proposals, representations, statements or understandings, whether
written or oral, concerning the Services or the parties' rights or obligations
relating to the Services. Any prior representations, promises, inducements or
statements of intent regarding the Services that are not embodied in this
Agreement are of no effect.

36. DEFINITIONS. The following definitions apply in addition to the definitions
set forth elsewhere in this Agreement:

"Affiliate" - any entity that controls, is controlled by or is under common
control with a party.

"End User" - the entity that actually uses the service resold by CUSTOMER.

"Intermediate Reseller" - any reseller or other intermediary (other than
CUSTOMER or its agents or employees) In the sales chain between CUSTOMER and an
End User.

"Tariff" - the AT&T Tariffs identified in the Attachments; and the successor
documents of general applicability that replace such tariffs in the event of
detariffing.

If not otherwise defined, capitalized terms shall be defined as provided in
AT&T's Tariffs.

                           End of Terms and Conditions

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<PAGE>   7

Supplemental Terms and Conditions                                    Page 1 of 1


                   ATTACHMENT TO AT&T MASTER CARRIER AGREEMENT

CUSTOMER Name (Full Legal Name): Universal Access, Inc.

Date of execution of Master Carrier Agreement:
                                             /s/ ROBERT J. POMMER
                                                  (by CUSTOMER)
                                              --------------------

                                              /s/ JAMES M. DOWNEY, JR. (by AT&T)
                                              --------------------

The Terms and Conditions of the AT&T Master Carrier Agreement are hereby revised
as follows:

1. The second sentence of SECTION 10 is amended with the following italicized
language:

               If CUSTOMER is in breach of its payment obligations (including
               failure to pay a required deposit), and fails to make payment in
               full within ten (10) days after receipt of written notice of
               default...

3. The last sentence of SECTION 14 is amended to add the following at the end of
the sentence:

               ...its employees, agents, subsidiaries, affiliates, successors
               and assigns.

4. The following sentence is added at the end of SECTION 22:

               This Section shall not limit a party's right to commence legal
               action with respect to any dispute that does not concern a
               Billing Dispute.

                                End of Attachment

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<PAGE>   8

Data Service Terms and Pricing                                      Page 1 of 11


                   ATTACHMENT TO AT&T MASTER CARRIER AGREEMENT

CUSTOMER Name (Full Legal Name): Universal Access, Inc.

Date of execution of Master Carrier Attachment:
                                              /s/ ROBERT J. POMMER
                                              --------------------

                                              /s/ JAMES M. DOWNEY, JR. (by AT&T)
                                              --------------------


1.      SERVICES PROVIDED. AT&T will provide the following Services to CUSTOMER
        under this Attachment and pursuant to the terms of the Master Carrier
        Agreement and the applicable Tariffs specified below.

        A.     AT&T PRIVATE LINE SERVICES. AT&T Private Line Services (AT&T
               Tariff F.C.C. No. 9, as amended from time to time) consisting of:

               1.     AT&T ACCUNET(R) Spectrum of Digital Services

               2.     AT&T DATAPHONE Digital Service

               3.     AT&T ACCUNET T1.5 Service

               4.     AT&T ACCUNET T45 Service

               5.     AT&T ACCUNET Fractional T45 Service

               6.     AT&T ACCUNET SONET T155 Service

               7.     AT&T International ACCUNET Spectrum of Digital
                      Services-Canada

               8.     AT&T International ACCUNET Spectrum of Digital
                      Services-Mexico

               9.     AT&T International ACCUNET T1.5 Service-Canada

               10.    AT&T International ACCUNET T1.5 Service-Mexico

               11.    AT&T International DATAPHONE Digital Service-Canada

               12.    AT&T International DATAPHONE Digital Service-Mexico

               13.    AT&T International ACCUNET Digital Services

               14.    AT&T International ACCUNET Digital Direct Link Service

               15.    AT&T International ACCUNET 2.048 Mbps Service-Mexico

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<PAGE>   9

Data Service Terms and Pricing                                      Page 2 of 11


               16.    AT&T International ACCUNET T45 Service-Canada

               17.    AT&T International ACCUNET T45 Service-Overseas

        B.     AT&T 1.544 MBPS ECHO CANCELLATION - AT&T 1.544 Mbps Echo
               Cancellation is an Office Function providing non-frequency
               selective echo cancellation in AT&T's central office to improve
               the quality of an AT&T T1.5 Inter Office Channel used for voice
               transmissions. Echo cancellation is disruptive to data
               transmissions, and is only available on an AT&T T1.5 Inter Office
               Channel that is designated by CUSTOMER for use for voice
               transmissions.

        C.     AT&T LOCAL CHANNEL SERVICES. AT&T Local Channel Services (AT&T
               Tariff F.C.C. No.11, as amended from time to time) consisting of:

               1.     AT&T TERRESTRIAL 1.544 Mbps Local Channel Services

               2.     AT&T TERRESTRIAL 45 Mbps Local Channel Services

               3.     AT&T Voice Grade Local Channel Service

               4.     AT&T Digital Data Local Channel Service

               5.     AT&T ACCUNET Generic Digital Access Services

        D.     AT&T SATELLITE SERVICES (AT&T Tariff F.C.C. No. 7, as amended
               from time to time) consisting of:

               1.     AT&T International Satellite Shared Earth Station Service

               2.     AT&T International Satellite Shared Earth Station Direct
                      Link Service

        E.     AT&T INTERSPAN(R) FRAME RELAY SERVICES. AT&T InterSpan Frame
               Relay Services (AT&T Tariff F.C.C. No. 4, as amended from time to
               time) consisting of:

               1.     AT&T InterSpan Frame Relay Service

               2.     AT&T International InterSpan Frame Relay Service

2.      TERM. The Term of this Attachment is 36 Months. This Attachment will
        be extended for additional 12 Months upon CUSTOMER's written request to
        AT&T 60 days prior to this Attachment expiration date. For each service
        provided under this Attachment, the Term begins on the first day of the
        first full billing month for the first service provided under this
        Attachment, which day is referred to as the Customer's Initial Service
        Date (CISD). Different Services may have different billing cycles, and
        so the billing months may be



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Data Service Terms and Pricing                                      Page 3 of 11


        staggered. For each service, however, the Term will begin within one
        month after the Term begins for the first service provided under this
        Agreement.

3.      MINIMUM REVENUE COMMITMENTS (MRC). The following Minimum Revenue
        Commitments apply under this Attachment. For each Minimum Revenue
        Commitment, CUSTOMER commits that the Eligible Charges it incurs during
        each Commitment Period will equal or exceed the amount of the
        commitment. If CUSTOMER fails to meet any Minimum Revenue Commitment in
        a Commitment Period, then CUSTOMER will pay a Shortfall Charge equal to
        the difference between the Minimum Revenue Commitment and the amount of
        Eligible Charges for that Minimum Revenue Commitment incurred during the
        Commitment Period. If CUSTOMER is in shortfall of the MRC by an amount
        less than or equal to the revenues associated with pending uninstalled
        orders, and such pending orders are not delayed due to the fault of
        CUSTOMER or its end-user, then AT&T agrees to consider granting
        temporary relief of the MRC.



        A.     ADJUSTABLE MINIMUM MONTHLY REVENUE COMMITMENTS (MMRCS).

               1.     At any time during the Term, CUSTOMER may elect to
                      increase any Adjustable MMRC to an amount that is less
                      than or equal to the CUSTOMER's billed MMRC Eligible
                      Charges for the most recent billing month, by providing
                      written notice to AT&T at least 30 days prior to the
                      beginning of the billing month for which the new MMRC will
                      apply.

        B.     ADJUSTABLE PRIVATE LINE AND SATELLITE MMRC.

               1.     For Months 1 through 6 of the Term, the initial Private
                      Line and Satellite MMRC is $0.0 Dollars. Beginning in
                      Month 7 through Month 36 of the Term, the initial Private
                      Line and Satellite MMRC is $250,000 Dollars. The Private
                      Line and Satellite MMRC is an adjustable MMRC described
                      above. Each month of the Term is a Commitment Period.



               2.     The Private Line and Satellite MMRC applies to the
                      following Services provided under this Attachment, except
                      it does not apply to Services to which another Adjustable
                      MMRC applies under this Attachment.

                      (a)    Services provided under this Agreement that if
                             provided under AT&T Tariff F.C.C. No. 9 would be
                             eligible to receive discount under the AT&T Tariff
                             F.C.C. No. 9 Multiservice Volume Pricing Plan

                      (b)    AT&T ACCUNET SONET T155 Service;

                      (c)    AT&T International ACCUNET Spectrum of Digital
                             Services-Canada



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Data Service Terms and Pricing                                      Page 4 of 11


                      (d)    AT&T International ACCUNET Spectrum of Digital
                             Services-Mexico

                      (e)    AT&T International ACCUNET T1.5 Service-Canada

                      (f)    AT&T International ACCUNET T1.5 Service-Mexico

                      (g)    AT&T International DATAPHONE Digital Service-Canada

                      (h)    AT&T International DATAPHONE Digital Service-Mexico

                      (i)    AT&T International ACCUNET Digital Services

                      (j)    AT&T International ACCUNET Digital Direct Link
                             Service

                      (k)    AT&T International ACCUNET 2.048 Mbps
                             Service-Mexico

                      (l)    AT&T International ACCUNET T45 Service-Canada

                      (m)    AT&T International ACCUNET T45 Service-Overseas

                      (n)    AT&T International Satellite Shared Earth Station
                             Service

                      (o)    AT&T International Satellite Shared Earth Station
                             Direct Link Service

               3.     The Eligible Charges for the Private Line and Satellite
                      MMRC consist of the net Monthly Recurring Charges for
                      these services, after the application of any discounts or
                      credits.

        C.     ADJUSTABLE FRAME RELAY MMRC.


               1.     The initial Frame Relay MMRC is $0.00 Dollars. The Frame
                      Relay MMRC is an adjustable MMRC described above. Each
                      month of the Term is a Commitment Period.



               2.     The Frame Relay-MRC applies to the Services provided under
                      this Attachment that if provided under AT&T Tariff F.C.C.
                      No. 4 would be eligible to receive discount under the AT&T
                      Tariff F.C.C. No. 4 Frame Relay Volume Pricing Plan.

               3.     The Eligible Charges for the Frame Relay MMRC consist of
                      the net Monthly Recurring charges for these services,
                      after the application of any discounts or credits.



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Data Service Terms and Pricing                                      Page 5 of 11


        D.     ADJUSTABLE LOCAL CHANNEL MMRC.


               1.     The initial Local Channel MMRC is $0.00 Dollars. The Local
                      Channel MMRC is an adjustable MMRC as described above.
                      Each month of the Term is a Commitment Period.



               2.     The Local Channel MMRC applies to the Services provided
                      under this Agreement that if provided under AT&T Tariff
                      F.C.C. No. 11 would be eligible to receive discount under
                      the AT&T Tariff F.C.C. No. 11 Multiservice Volume Pricing
                      Plan.

               3.     The Eligible Charges for the Local Channel MMRC consist of
                      the net Monthly Recurring charges for these services,
                      after the application of any discounts or credits.

4.      RATES AND CHARGES. The Recurring and Nonrecurring Rates and Charges for
        the Services provided under this Attachment are the same as the
        undiscounted Recurring and Nonrecurring Rates and Charges under the
        applicable Tariffs, as amended from time to time, except as specified in
        this Attachment. AT&T reserves the right to increase from time to time
        the rates for Services under this Agreement, regardless of any
        provisions that would otherwise stabilize rates or limit rate increases,
        relating to charges or payment obligations imposed on AT&T stemming from
        an order, rule or regulation of the Federal Communications Commission or
        a court of competent jurisdiction, concerning universal service fund
        ("USF") charges, or as otherwise needed to recover amounts it is
        required by governmental or quasi-governmental authorities to collect
        from or pay to others in support of statutory or regulatory programs.
        AT&T will make rate adjustments under this provision as necessary.

        A.     The Monthly Recurring Charge for an AT&T ACCUNET T1.5 Service IOC
               and its associated Access Connections and Function Connections is
               as follows. The Nonrecurring Installation Charge for the IOC is
               [***].

<TABLE>
<CAPTION>
                                                       Monthly Charge
                                                       --------------
                   Mileage Band                   Fixed               Per Mile
                   ------------                   -----               --------
<S>                                             <C>                   <C>
                       0-100                    [***]                  [***]
                       101+                     [***]                  [***]
</TABLE>

        B.     The Monthly Recurring Charge for an AT&T ACCUNET T45 Service IOC
               and its associated Access Connections and Function Connections is
               as follows. The Nonrecurring Installation Charge for the IOC is
               $0.00.

<TABLE>
<CAPTION>
                                                       Monthly Charge
                                                       --------------
                   Mileage Band                   Fixed               Per Mile
                   ------------                   -----               --------
<S>                                             <C>                   <C>
                       0-100                    [***]                  [***]
                       101+                     [***]                  [***]
</TABLE>



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<PAGE>   13

Data Service Terms and Pricing                                      Page 6 of 11


        C.     The Monthly Recurring Charge for an AT&T ACCUNET SONET T155
               Service IOC and its associated Access Connections and Function
               Connections is as follows. The Nonrecurring Installation Charge
               for the IOC is [***]. A twelve-month Minimum In-Service Period
               applies for each AT&T ACCUNET SONET T155 Service IOC installed.
               If any such AT&T ACCUNET SONET T155 Service IOC is disconnected
               prior to the end of the Minimum In-Service Period, CUSTOMER will
               be billed for the remaining Minimum In-Service period times the
               Monthly Recurring Charges of SONET T155 Service plus the
               Nonrecurring Installation Charge for the IOC of [***].

<TABLE>
<CAPTION>
                                                       Monthly Charge
                                                       --------------
                   Mileage Band                   Fixed               Per Mile
                   ------------                   -----               --------
<S>                                             <C>                   <C>
                       0-100                    [***]                  [***]
                       101+                     [***]                  [***]
</TABLE>

        D.     When AT&T 1.544 Mbps Echo Cancellation is associated with an AT&T
               ACCUNET T1.5 IOC, the Monthly Charge is [***] per IOC and the
               Non-recurring Installation Charge is [***] per IOC.

5.      DISCOUNTS. The following monthly discounts are the only discounts for
        the Services provided under this Attachment. No other discounts apply.

        A.     PRIVATE LINE AND SATELLITE SERVICES. A discount will be applied
               each month, as specified following, to the Monthly Recurring
               Charges for the Services to which the Private Line and Satellite
               MMRC applies.

               1.     AT&T Private Line Services.

                      (a)    AT&T ACCUNET T1.5 Service IOCs- [***] Discount.

                      (b)    AT&T ACCUNET T45 Service IOC - [***] Discount.

                      (c)    AT&T ACCUNET SONET T155 Service IOC - [***]
                             Discount.

                      (d)    For all other domestic AT&T Private Line Services,
                             the amount of the discount is the same as the
                             discount specified in AT&T Tariff F.C.C. No. 9, for
                             a three (3) year Multi-Service Volume Pricing Plan
                             ("MSVPP") with the highest MMRC equal to or less
                             than the Private Line and Satellite MMRC that
                             applies under this Agreement for that month.

               2.     AT&T International Private Line Services. A discount will
                      be applied each month to the Monthly Recurring charges for
                      the following AT&T International Private Line Services.
                      The amount of the discount will be determined each month
                      based on the Private Line and Satellite MMRC Eligible
                      Charges for that month, as specified in the following
                      table:


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        respect to the omitted portions.

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<PAGE>   14

Data Service Terms and Pricing                                      Page 7 of 11


                        Service                                         Discount

                        AT&T International ACCUNET Spectrum of          [***]
                        Digital Services
                        -Canada and Mexico
                        -Speeds equal to and less
                        than 64Kbps

                        AT&T International ACCUNET Spectrum of          [***]
                        Digital Services
                        -Canada and Mexico
                        -Speeds equal to and greater than 128Kbps

                        AT&T International ACCUNET T1.5 Service-        [***]
                        Canada and Mexico

                        AT&T International DATAPHONE Digital            [***]
                        Service
                        -Canada and Mexico

                        AT&T International ACCUNET Digital Services     [***]

                        AT&T International ACCUNET Digital Direct       [***]
                        Link Service

                        AT&T International ACCUNET 2.048 Mbps           [***]
                        Service
                        -Mexico

                        AT&T International ACCUNET T45 Service          [***]
                        -Canada

                        AT&T International ACCUNET T45 Service          [***]
                        -Overseas

               3.     AT&T Satellite Services. A discount will be applied each
                      month to the Monthly Recurring charges for the following
                      AT&T International Satellite Services. The amount of the
                      discount will be determined each month based on the
                      Private Line and Satellite MMRC Eligible Charges for that
                      month, as specified in the following table:

                      Service                                    Discount

                      AT&T International Satellite                 [***]
                      Services
                      -Shared Earth Station, and
                      -Shared Earth Station Direct Link
                      Service

        B.     LOCAL CHANNEL SERVICES. A discount will be applied each month to
               the Monthly Recurring Charges for the Services to which the Local
               Channel MMRC applies

               1.     AT&T TERRESTRIAL T1.5 Local Channel Service - [***]
                      Discount.

               2.     AT&T TERRESTRIAL T45 Local Channel Service - [***]
                      Discount.


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        respect to the omitted portions.

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<PAGE>   15

Data Service Terms and Pricing                                      Page 8 of 11


               3.     For all other AT&T Local Channel Services, the amount of
                      the discount is the same as the discount specified in AT&T
                      Tariff F.C.C. No. 11, for a three (3) year Multi-Service
                      Volume Pricing Plan with the highest MMRC equal to or less
                      than the Local Channel MMRC that applies under this
                      Agreement for that month.

        C.     AT&T FRAME RELAY SERVICES. A discount will be applied each month
               to the Monthly Recurring Charges for the Frame Relay Services
               that, if provided under AT&T Tariff F.C.C. No. 4, as amended from
               time to time, would be eligible to receive discount under the
               Frame Relay Volume Pricing Plan.

6.      CREDITS AND WAIVERS. The following credits and waivers are the only
        credits and waivers that apply to the Services provided under this
        Attachment. No other promotions, credits or waivers apply. The maximum
        combined value of the credits that will be applied and the Nonrecurring
        Installation charges that will be waived under this Section 6 shall not
        exceed [***] during the Term of this Attachment.

        A.     CREDIT FOR INSTALLATION OF LOCAL CHANNELS SUBJECT TO AVA OR AVP.
               AT&T will apply a credit to offset the amount of Installation
               Charges incurred by CUSTOMER under Tariff F.C.C. No. 11, as
               amended from time to time, for the installation of 1.544 Mbps or
               45 Mbps Local Channels under a Tariff 11 Access Value Arrangement
               (AVA) or Access Value Plan (AVP) for use in connection with
               another Service provided under this Attachment. No credit applies
               with respect to Local Channels that are disconnected and
               reconnected after this Attachment is made part of the Agreement.

               1.     Minimum In-Service Period. A twelve-month Minimum
                      In-Service Period applies for any Local Channels with
                      respect to which such a credit is applied. If any such
                      Local Channel is disconnected prior to the end of the
                      Minimum In-Service Period, CUSTOMER will be billed an
                      amount equal to the credit previously applied with respect
                      to that Local Channel.

               B.     Non Recurring Installation Charge Waiver. AT&T will waive
                      the Nonrecurring Installation Charges associated with the
                      installation of certain Services or service components
                      provided under this Attachment. No waiver applies to
                      Services or service components that are disconnected and
                      reconnected after this Attachment is made part of the
                      Agreement.

                      1.    Minimum In-Service Period. A twelve Month Minimum
                            In-Service Period applies for any service components
                            installed subject to a waiver of Installation
                            Charges. If any such service component is
                            disconnected prior to the end of the Minimum In-
                            Service Period, CUSTOMER will be billed for the
                            Installation Charges previously waived for that
                            service component.



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        respect to the omitted portions.

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<PAGE>   16

Data Service Terms and Pricing                                      Page 9 of 11



               2.     Charges Covered by Waiver. This Installation Charge Waiver
                      applies only to the following charges that would otherwise
                      be incurred for Services provided under this Attachment:


                      (a)    AT&T MSVPP-Eligible Private Line Services -
                             Installation Charges for AT&T Private Line Services
                             provided under this Attachment that, if provided
                             under AT&T Tariff F.C.C. No. 9, as amended from
                             time to time, would be eligible to receive discount
                             under the Tariff 9 Multiservice Volume Pricing
                             Plan. This Installation Charge Waiver does not
                             apply to any Access Connection or Function
                             Connection which provides the physical connection
                             to (i) Custom Network Service obtained from AT&T
                             Tariff F.C.C. No. 1, (ii) AT&T MultiQuest Service
                             obtained from AT&T Tariff F.C.C. No. 1, or (iii)
                             Custom 800 Service obtained from AT&T Tariff F.C.C.
                             No. 2;

                      (b)    AT&T FRVPP-Eligible Frame Relay Services -
                             Installation Charges for AT&T Frame Relay Services
                             provided under this Attachment that, if provided
                             under AT&T Tariff F.C.C. No. 4, as amended from
                             time to time, would be eligible to receive discount
                             under the Tariff 4 Frame Relay Volume Pricing Plan;

                      (c)    AT&T International ACCUNET Spectrum of Digital
                             Services-Canada

                      (d)    AT&T International ACCUNET Spectrum of Digital
                             Services-Mexico

                      (e)    AT&T International ACCUNET T1.5 Service-Canada

                      (f)    AT&T International ACCUNET T1.5 Service-Mexico

                      (g)    AT&T International DATAPHONE Digital Service-Canada

                      (h)    AT&T International DATAPHONE Digital Service-Mexico

                      (i)    AT&T International ACCUNET Digital Services

                      (j)    AT&T International ACCUNET Digital Direct Link
                             Service

                      (k)    AT&T International ACCUNET 2.048 Mbps
                             Service-Mexico

                      (l)    AT&T International ACCUNET T45 Service-Canada

                      (m)    AT&T International ACCUNET T45 Service-Overseas



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Data Service Terms and Pricing                                     Page 10 of 11


                      (n)    AT&T International Satellite Shared Earth Station
                             Service

                      (o)    AT&T International Satellite Shared Earth Station
                             Direct Link Service

                      (p)    AT&T MSVPP-Eligible Local Channel Services -
                             Installation Charges for AT&T Local Channel
                             Services provided under this Attachment that, if
                             provided under AT&T Tariff F.C.C. No. 11, as
                             amended from time to time, would be eligible to
                             receive discount under the Tariff 11 Multiservice
                             Volume Pricing Plan; and

                      (q)    AT&T ACCUNET Service Office Connections, Channel
                             Options and Office

                             Functions - Installation Charges for the following
                             AT&T ACCUNET Service Office Connections, Channel
                             Options and Office Functions, when associated with
                             Inter Office Channels installed under this
                             Agreement. This Installation Charge Waiver does not
                             apply to any Access Connection or Function
                             Connection which provides the physical connection
                             to (i) Custom Network Service obtained from AT&T
                             Tariff F.C.C. No. 1, (ii) AT&T MultiQuest Service
                             obtained from AT&T Tariff F.C.C. No. 1, or (iii)
                             Custom 800 Service obtained from AT&T Tariff F.C.C.
                             No. 2.

                             (1)    AT&T ACCUNET T1.5 Service Access Connections
                                    (USOC O41AC)

                             (2)    AT&T ACCUNET T1.5 Service Function
                                    Connections (USOC NRZFC)

                             (3)    AT&T ACCUNET T1.5 Service Enhanced Diversity
                                    Routing (USOC DY7D1)

                             (4)    AT&T ACCUNET T1.5 Service Specified Routing
                                    and Avoidance (USOC DY7AS)

                             (5)    AT&T ACCUNET T45 Service Access Connections
                                    (USOC O41AC)

                             (6)    AT&T ACCUNET T45 Service Function
                                    Connections (USOC NRZFC)

                             (7)    AT&T ACCUNET T45 Service Enhanced Diversity
                                    Routing (USOC DY7D1)

                             (8)    AT&T ACCUNET T45 Service Specified Routing
                                    and Avoidance (USOC DY7AS)

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<PAGE>   18

Data Service Terms and Pricing                                     Page 11 of 11


                             (9)    AT&T ACCUNET T45 Service M28 Multiplexing
                                    (USOC M2X)

                             (10)   AT&T ACCUNET SONET T155 Service Access
                                    Connections (USOC 041AC)

                             (11)   AT&T ACCUNET SONET T155 Service Function
                                    Connections (USOC NRZFC)

                             (12)   AT&T 1.544 Mbps Echo Cancellation

7.      CLASSIFICATIONS, PRACTICES AND REGULATIONS. Except as otherwise provided
        in this Attachment, the rates and regulations that apply to the Services
        provided under this Attachment are as set forth in the applicable
        Tariffs.

        A.     DETARIFFING. If, during the Term of this Attachment, any of the
               tariffs of AT&T referenced herein are canceled, in whole or in
               part, pursuant to a statutory change, order or requirement of a
               governmental or judicial authority of competent jurisdiction
               requiring detariffing, then, following such cancellation, any
               rates, terms and conditions of such tariffs that had been
               applicable to the Services provided under this Agreement will
               continue to apply, based on the language of the tariffs in effect
               as of the date of cancellation.

        B.     DEFINITIONS. Terms not otherwise defined in this Attachment or in
               the Agreement have the meanings provided in the applicable
               Tariffs.

8.      TERMINATION CHARGE. The following provision applies in lieu of any
        Discontinuance With or Without Liability provisions specified in the
        applicable Tariffs.

        A.     If CUSTOMER terminates this Attachment prior to the end of the
               Term, or if AT&T terminates this Attachment or the Service
               provided under this Attachment prior to the end of the Term due
               to CUSTOMER's breach of the Agreement, CUSTOMER will be billed a
               Termination Charge. The Termination Charge will be an amount
               equal to 50% of the unsatisfied Minimum Revenue Commitment(s)
               for the Commitment Period(s) in which the termination occurs,
               plus 50% of the Minimum Revenue Commitments for each Commitment
               Period remaining in the Term. In addition, CUSTOMER will be
               billed an amount equal to the sum of any credits provided under
               this Attachment.

                                End of Attachment

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