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                                                                     EXHIBIT 4.3

                       FORM OF CREDIT FACILITY AGREEMENT


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                            CREDIT FACILITY AGREEMENT

                                  $100,000,000

                                      among

                            GLOBAL CARD HOLDINGS INC.

                                    as Lender

                                       and

                            AT&T LATIN AMERICA CORP.

                                   as Borrower

                                       and

                             NETSTREAM TELECOM LTDA.

                            As a Borrowing Subsidiary

                                       and

                                 KEYTECH LD S.A.

                            As a Borrowing Subsidiary

                         Dated as of [________ __], 2000

                       ----------------------------------



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                                TABLE OF CONTENTS

                                                                           PAGE
                                                                           ----

1.    LOANS     ..............................................................1

2.    PROCEDURES FOR ADVANCES OF LOANS........................................1

3.    REPAYMENT; REDUCTION OF AGGREGATE COMMITMENT............................2

4.    NOTES     ..............................................................4

5.    INTEREST  ..............................................................4

6.    USE OF PROCEEDS.........................................................5

7.    RANKING OF OBLIGATIONS..................................................5

8.    COLLATERAL..............................................................5

9.    REPRESENTATIONS AND WARRANTIES OF THE BORROWER..........................6

10.   COVENANTS:..............................................................8

11.   EVENTS OF DEFAULT......................................................12

12.   REMEDIES UPON DEFAULT, ETC.............................................13

13.   WITHHOLDING............................................................14

14.   INCREASED COSTS........................................................15

15.   INDEMNITIES............................................................15

16.   CHANGE IN MARKET CONDITIONS............................................17

17.   DEFINITIONS............................................................17

18.   APPLICABLE LAW/SUBMISSION TO JURISDICTION..............................22

19.   ASSIGNMENT.............................................................22

20.   COUNTERPARTS...........................................................22

Schedule A   List of Borrowing Subsidiaries
Exhibit A  Form of Borrowing Notice
Exhibit B  Form of Note




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           Credit Facility Agreement, dated as of July __, 2000 ("AGREEMENT"),
among Global Card Holdings Inc., a Delaware corporation (the "LENDER"), AT&T
Latin America Corp., a Delaware corporation (the "BORROWER") and each Person
listed on Schedule A hereto (each, a "BORROWING SUBSIDIARY").

                                    RECITALS

           A. The Borrower has requested the Lender to make loans available to
the Borrower and the Borrowing Subsidiaries in one or more drawdowns in an
aggregate principal amount not exceeding $100,000,000 (such amount, as reduced
hereunder from time to time, the "AGGREGATE COMMITMENT"); and

           B. The Lender is willing to make loans to the Borrower and/or one or
more of the Subsidiaries under the terms and subject to the conditions set forth
in this Agreement.

           In consideration of the mutual promises and covenants set forth
herein, the parties agree as follows:

1.    LOANS

      Subject to the terms and conditions of this Agreement, the Lender agrees
      to make one or more loans hereunder (each, a "LOAN") to the Borrower
      and/or the Borrowing Subsidiaries from time to time during the period from
      the date of this Agreement to the Termination Date, as requested by the
      Borrower in accordance with Section 2, PROVIDED that, subject to Section
      3(b), the aggregate principal amount of all outstanding Loans shall not
      exceed the Aggregate Commitment at any time. The Borrowing Subsidiaries
      listed on Schedule A may be changed from time to time as agreed by Lender
      and Borrower provided that any Person added to such list becomes a party
      to this Agreement.

2.    PROCEDURES FOR ADVANCES OF LOANS

         (a)      REQUESTS FOR BORROWING. The Borrower shall give the Lender a
                  notice of each Loan in the form of Exhibit A (a "BORROWING
                  NOTICE"), duly executed by its Chief Executive Officer or
                  Chief Financial Officer, not later than the fifth Business Day
                  prior to the borrowing date of such Loan of its intention to
                  borrow, specifying (I) the principal amount of such Loan in
                  Dollars, which shall be in an aggregate amount of $2,000,000
                  or an integral multiple of $1,000,000 in excess thereof (not
                  to exceed, together with any outstanding Loans, the Aggregate
                  Commitment), (II) the borrowing date of such Loan, which
                  shall be a Business Day, (III) the name of any Borrowing





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                  Subsidiary proposed to be a borrower and (IV) the bank account
                  or accounts of the Borrower (or Borrowing Subsidiary) to which
                  the Loan is to be disbursed, and certifying, as of the date of
                  the Borrowing Notice and as of the borrowing date, that (W)
                  the Borrower and the Borrowing Subsidiaries have performed and
                  complied with all the respective terms and conditions of this
                  Agreement applicable to them, (X) the representations and
                  warranties contained in Section 9 are and will be true and
                  correct; (Y) there exists and will exist no condition or event
                  which constitutes or which, after notice or passage of time or
                  both, would constitute an Event of Default, and (Z) the amount
                  of the Loan specified in the Borrowing Notice is consistent
                  with the most recently delivered Business Plan. Any Borrowing
                  Notice received after 12:00 noon (New York time) shall be
                  deemed received on the next Business Day. If the Borrower
                  requests in a Borrowing Notice pursuant to this Section that
                  all or a portion of an amount of the Loan specified therein be
                  made available to one or more Borrowing Subsidiaries, Borrower
                  must deliver the Borrowing Notice to Lender not later than (I)
                  20 Business Days prior to the requested borrowing date if any
                  relevant Borrowing Subsidiary is domiciled in Colombia or
                  Brazil; or (II) 10 Business Days prior to the requested
                  borrowing date if any relevant Borrowing Subsidiary is
                  domiciled in Peru, Argentina or Chile.

         (b)      DISBURSEMENT OF LOANS. Subject to the terms and conditions of
                  this Agreement, not later than 5:00 p.m. on the borrowing date
                  set forth in a Borrowing Notice with respect to a Loan
                  complying with paragraph (a) of this Section, the Lender shall
                  make available to the Borrower the amount of such Loan in U.S.
                  Dollars specified in such Borrowing Notice, in immediately
                  available funds payable to the account or accounts specified
                  in such Borrowing Notice, PROVIDED that at the request of
                  Borrower, Lender may, in its sole discretion, make available
                  to a Borrowing Subsidiary all or a portion of an amount of the
                  Loan specified in the Borrowing Notice on a borrowing date to
                  be agreed between the Lender and the Borrower, which date,
                  except as otherwise agreed by Lender, shall be not earlier
                  than (I) 20 Business Days after receipt of the Borrowing
                  Notice if the relevant Borrowing Subsidiary is domiciled in
                  Colombia or Brazil or (II) 10 Business Days after receipt of
                  the Borrowing Notice if the relevant Borrowing Subsidiary is
                  domiciled in Peru, Argentina or Chile.

3.    REPAYMENT; REDUCTION OF AGGREGATE COMMITMENT

         (a)      FINAL MATURITY. The Borrower shall repay, or cause the
                  relevant Borrowing Subsidiaries to repay, as the case may be
                  (including without limitation by providing funds to such
                  Borrowing Subsidiary for such payment), all Loans (or such
                  principal amount as shall then be outstanding) on July ___,
                  2002, or, if FirstCom Corporation has merged with a subsidiary




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                  of AT&T Latin America, the second annual anniversary of the
                  date of consummation of such merger (or if such date is not a
                  Business Day, the next succeeding Business Day), together with
                  accrued interest through such date.

         (b)      REDUCTION OF AGGREGATE COMMITMENT/MANDATORY PREPAYMENT. (i)
                  The amount of the Aggregate Commitment shall be reduced
                  automatically by the amount of the aggregate net cash proceeds
                  from any issuance by the Borrower or any Subsidiary from time
                  to time of (X) Indebtedness, other than Permitted
                  Indebtedness, or (Y) equity securities or similar interests,
                  other than in connection with the exercise of stock options by
                  employees pursuant to an authorized plan of such Borrower or
                  Subsidiary.

                  (ii) If at any time, the aggregate amount of outstanding Loans
                  exceeds the Aggregate Commitment then in effect, the Borrower
                  shall prepay, or cause the relevant Borrowing Subsidiaries to
                  prepay, as the case may be (including without limitation by
                  providing funds to such Borrowing Subsidiary for such payment)
                  an amount equal to the excess of the aggregate amount of
                  outstanding Loans over such Aggregate Commitment, such
                  prepayment to be made, together with accrued interest on the
                  amount prepaid through the date of prepayment, not more than
                  three Business Days following any date on which the aggregate
                  amount of outstanding Loans exceeds the Aggregate Commitment.

         (c)      OPTIONAL PREPAYMENT. The Borrower (or any Borrowing
                  Subsidiary) may prepay Loans in whole or in part without
                  penalty or premium, but together with accrued interest on the
                  amount prepaid through the date of prepayment, PROVIDED that
                  the Borrower shall give the Lender notice of any such
                  prepayment at least three Business Days in advance.

         (d)      PREPAYMENT ON ACCOUNT OF ILLEGALITY. Notwithstanding any other
                  provision herein, if the adoption of or any change in any
                  Requirement of Law applicable to Lender, Borrower or any
                  Borrowing Subsidiary or in the interpretation or application
                  thereof occurring after the date of this Agreement shall make
                  it unlawful for the Lender to make or maintain any Loan, (i)
                  the Lender shall promptly give written notice of such
                  circumstances to the Borrower (which notice shall be withdrawn
                  whenever such circumstances no longer exist), and (II) the
                  Borrower shall repay (or cause its applicable Borrowing
                  Subsidiary to repay) the amount of such Loan, together with
                  any interest accrued thereon, within three Business Days
                  following receipt of such notice from the Lender.

         (e)      REPAYMENT IN EVENT OF DEFAULT. If an Event of Default shall
                  have occurred and be continuing, the Loan may be declared
                  payable immediately, or will become repayable immediately, in
                  accordance with Section 11.




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         (f)      PAYMENT IN U.S. DOLLARS. Any payment under this Agreement or
                  the Notes shall be in U.S. Dollars.

4.    NOTES

      The Borrower's or any Borrowing Subsidiary's obligation to pay the
      principal of and interest on each Loan shall be evidenced by a note
      payable to the Lender (a "NOTE"), which shall (I) be dated on the date of
      borrowing of such Loan, (II) be in the stated principal amount set forth
      in the corresponding Borrowing Notice, (III) bear interest as provided in
      Section 5, (iv) be payable in Dollars to the order of the Lender, (V) be
      duly executed by a duly authorized officer of the Borrower or the relevant
      Borrowing Subsidiary, and (VI) be in the form of Exhibit B with blanks
      completed in conformity herewith and therewith. The Borrower shall
      deliver, or cause to be delivered, to the Lender a duly executed Note with
      respect to each Loan not later than the date on which such Loan is
      disbursed.

5.    INTEREST

         (a)      INTEREST RATE. Subject to the provisions of this Section 5,
                  the outstanding principal amount of each Loan shall bear
                  interest at a rate per annum equal to the LIBOR Rate plus the
                  Margin as set forth below.

         (b)      INTEREST PERIODS. The Interest Period (the "INTEREST PERIOD")
                  for each Loan shall be a period of three months, PROVIDED
                  that:

                  (i)      the initial Interest Period shall commence on the
                           next succeeding date after the date of disbursement,
                           and each subsequent Interest Period shall commence on
                           the next succeeding date after the date on which the
                           next preceding Interest Period expires; and

                  (ii)     if any Interest Period would otherwise expire on a
                           date that is not a Business Day, such Interest Period
                           shall expire on the next succeeding Business Day.

         (c)      DEFAULT RATE. Upon the occurrence and during the continuance
                  of an Event of Default, all Loans shall bear interest at a
                  rate per annum that is 2% in excess of the rate then
                  applicable.

         (d)      INTEREST PAYMENT AND COMPUTATION. Interest on each Loan shall
                  be payable on the last day of each Interest Period applicable
                  thereto. Interest shall be computed on the basis of a 360-day
                  year or 30-day months and assessed for the actual number of
                  days elapsed.



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         (e)      LIBOR RATE; MARGIN. The "LIBOR RATE" shall be the per annum
                  rate of interest determined on the basis of the London
                  Inter-Bank Offered Rate for deposits in Dollars in minimum
                  amounts of $5,000,000 for a three-month period appearing on
                  Bloomberg (function: BBAM) as of two Business Days prior to
                  the date of disbursement of the applicable Loan. The "MARGIN"
                  shall be 3.75% per annum.

6.    USE OF PROCEEDS

      The Borrower and its Subsidiaries shall use the proceeds of the Loans (I)
      to finance Capital Expenditures and working capital requirements, (II) to
      pay cash interest, and (III) to fund operating costs.

7.    RANKING OF OBLIGATIONS.

      So long as any Loan or any portion thereof is outstanding under this
      Agreement, the payment obligations of the Borrower or any Borrowing
      Subsidiary with respect thereto will at all times rank at least equally
      and ratably in all respects with all present and future unsecured
      Indebtedness of such Person from time to time outstanding except for such
      unsecured Indebtedness as would, by virtue only of the operation of law,
      be preferred in the event of the winding-up of the Borrower or any such
      Borrowing Subsidiary, as the case may be.

8.    COLLATERAL.

         (a)      PROVISION OF SECURITY. Upon the request of the Lender, which
                  request may be made in the Lender's sole discretion at any
                  time, including upon the granting of any security by Borrower
                  or its Subsidiaries to any other lender, the Borrower shall,
                  and shall cause each of its Subsidiaries as requested by the
                  Lender to:

                  (i)      pledge in favor of the Lender or its designee or
                           agent all of the shares or other equity interests
                           owned by it in any Subsidiary to secure the
                           obligations of Borrower and Borrowing Subsidiaries
                           hereunder; and/or

                  (ii)     grant to the Lender or its designee or agent a
                           security interest over any tangible or intangible
                           assets of the Borrower or any Subsidiary to secure
                           the obligations of Borrower and Borrowing
                           Subsidiaries hereunder.

         (b)      SECURITY ARRANGEMENTS. If the Lender shall have requested the
                  Borrower or any Subsidiary to provide a pledge of shares or
                  grant of a security interest over assets, the Borrower shall,
                  and shall cause the relevant Subsidiary or Subsidiaries to:





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                  (i)      execute and deliver all such documents and
                           instruments, and make all filings, as are reasonably
                           necessary to create in favor of the Lender or its
                           designee or agent a valid and enforceable security
                           interest over the property to be pledged or given as
                           security; and

                  (ii)     deliver to the Lender an opinion or opinions of
                           counsel, reasonably acceptable to the Lender, as to
                           the validity and enforceability of the pledge or
                           security interest in the jurisdiction in which it is
                           made or granted.

         9.       REPRESENTATIONS AND WARRANTIES OF THE BORROWER. The Borrower,
                  with respect to itself and its Subsidiaries, and each
                  Borrowing Subsidiary, with respect to itself and its
                  Subsidiaries, represents and warrants to the Lender as
                  follows:

         (a)      DUE ORGANIZATION, VALID EXISTENCE, GOOD STANDING, DUE
                  AUTHORIZATION, ENFORCEABILITY. The Borrower is a corporation
                  duly organized, validly existing and in good standing under
                  the laws of Delaware and has the corporate power and authority
                  to execute and deliver this Agreement and perform its
                  obligations hereunder. Each Subsidiary is a corporation,
                  limited liability company or other business entity duly
                  organized, validly existing and, if applicable, in good
                  standing under the laws of the jurisdiction in which it is
                  organized. The execution and delivery of this Agreement and
                  the performance of the Borrower's and the Borrowing
                  Subsidiaries' obligations hereunder have been duly authorized
                  by all necessary action on the part of the Borrower and such
                  Borrowing Subsidiary, as the case may be. This Agreement has
                  been duly executed and delivered by the Borrower and each
                  Borrowing Subsidiary and constitutes the legal, valid and
                  binding obligation of the Borrower and each Borrowing
                  Subsidiary, as the case may be.

         (b)      NO VIOLATION, CONFLICT, DEFAULT, LIENS, CONSENTS, APPROVALS.
                  The execution and delivery of this Agreement by the Borrower
                  and each Borrowing Subsidiary and the performance by the
                  Borrower and each Borrowing Subsidiary of its obligations
                  hereunder will not result in (I) any conflict with the
                  organizational documents of the Borrower or any Subsidiary,
                  (ii) any breach or violation of or default under any law,
                  statute, regulation, judgment, order, decree, license, permit
                  or other governmental authorization or any mortgage, lease,
                  agreement, deed of trust, indenture or any other instrument to
                  which the Borrower or any Subsidiary of the Borrower is a
                  party or by which any of them or their respective properties
                  or assets are bound, or (III) except as provided herein, the
                  creation or imposition of any Liens, except for such breaches,
                  violations or defaults and such Liens which would not,
                  individually or in the aggregate, reasonably be expected





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                  to have a material adverse effect (a "MATERIAL ADVERSE
                  EFFECT") on the ability of Borrower and the Borrowing
                  Subsidiaries to perform their obligations under this Agreement
                  or with respect to any Loan. No consent, approval or
                  authorization of or filing with any third party or any
                  governmental authority is required on the part of the Borrower
                  or any of the Subsidiaries of the Borrower in connection with
                  the execution and delivery of this Agreement or the
                  consummation of the transactions contemplated hereby or the
                  performance of any obligations of Borrower or any of the
                  Borrowing Subsidiaries hereunder.

         (c)      NO MATERIAL ADVERSE CHANGE. Since March 31, 2000, there has
                  been no change, occurrence or development resulting in a
                  Material Adverse Effect.

         (d)      NO LITIGATION. (I) There is no pending or, to the best
                  knowledge of the Borrower and the Borrowing Subsidiaries,
                  threatened action or suit or judicial, arbitral, rule-making
                  or other administrative or other proceeding before any court
                  of governmental agency, authority or body or any arbitrator
                  involving the Borrower or any of the Subsidiaries that would
                  reasonably be expected to have a Material Adverse Effect, and
                  (II) there is no pending or, to the best knowledge of the
                  Borrower and the Borrowing Subsidiaries, threatened action or
                  suit or judicial, arbitral, rule-making or other
                  administrative or other proceeding which questions the
                  validity of this Agreement or any action taken or to be taken
                  pursuant hereto.

         (e)      FEDERAL REGULATIONS. No part of the proceeds of any Loan will
                  be used for "buying" or "carrying" any "margin stock" within
                  the respective meanings of each of the quoted terms under
                  Regulation U of the Federal Reserve Board, or for any purpose
                  which violates the provisions of the Regulations of the
                  Federal Reserve Board, including, without limitation,
                  Regulation T, Regulation U or Regulation X of the Federal
                  Reserve Board.

         (f)      OWNERSHIP OF PROPERTY; LIENS. Each of the Borrower and its
                  Subsidiaries has good and valid title to, or a valid leasehold
                  interest in, all its material real property, and good title
                  to, or a valid leasehold interest in, all its other material
                  property, and none of such property is subject to any Liens,
                  except Permitted Liens.

         (g)      INVESTMENT COMPANY ACT. Neither the Borrower nor any of the
                  Subsidiaries is an "investment company" or a "company
                  controlled by an investment company" within the meaning of the
                  United States Investment Company Act of 1940, as amended.

         (h)      PUBLIC UTILITY HOLDING COMPANY ACT. Neither the Borrower nor
                  any of the Subsidiaries is a "holding company" or an






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                  "affiliate of a holding company" within the meaning of the
                  United States Public Utility Holding Company Act of 1935, as
                  amended.

         (i)      FOREIGN ASSETS CONTROL REGULATIONS, ETC. Neither the making of
                  any Loan nor the use of the proceeds thereof as contemplated
                  by this Agreement will violate any requirement or prohibition
                  imposed by the United States government under authority of the
                  International Emergency Economic Powers Act (50 U.S.C. ss
                  1701, ET SEQ.), the Trading with the Enemy Act (50 U.S.C. App.
                  5(b)), or any proclamation, order, regulation or license
                  issued pursuant thereto.

         (j)      TAXES. The Borrower and each of the Subsidiaries have duly and
                  timely filed or caused to be duly and timely filed all tax
                  returns which are required to be filed and have duly and
                  timely paid all taxes shown to be due and payable on such
                  returns or on any assessments made against it or any of its
                  property by a government authority or otherwise payable by it
                  (other than any amount the validity of which is currently
                  being contested in good faith by appropriate proceedings and
                  with respect to which adequate reserves have been established
                  in the books of the Borrower or the Subsidiaries, as the case
                  may be) except to the extent that failure to comply with this
                  paragraph would not be reasonably expected to have a Material
                  Adverse Effect.

10.   COVENANTS:

         (a)      ANNUAL BUSINESS PLAN. Prior to the beginning of each fiscal
                  year of the Borrower, the Borrower shall deliver to Lender an
                  annual business plan with respect to the Group (the "BUSINESS
                  PLAN"), approved by the Board of Directors of Borrower, that
                  sets forth in reasonable detail (I) the financing needs of the
                  Group and expected financing sources; and (II) the amount of
                  proposed Capital Expenditures for each month in such year.
                  Borrower shall promptly provide to Lender an updated Business
                  Plan, approved by the Board of Directors of Borrower, upon any
                  material change to the Business Plan most recently delivered
                  to Lender.

         (b)      USE OF PROCEEDS/MARGIN REGULATIONS. The Borrower shall, and
                  shall cause its Subsidiaries to, use the proceeds of Loans in
                  accordance with Section 6. The Borrower shall not, and shall
                  cause its Subsidiaries not to, use any part of the proceeds of
                  any Loan for "buying" or "carrying" any "margin stock" within
                  the respective meanings of each of the quoted terms under
                  Regulation U of the Federal Reserve Board, or for any purpose
                  which violates the provisions of the Regulations of the
                  Federal Reserve Board, including, without limitation,
                  Regulation T, Regulation U or Regulation X of the Federal






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                  Reserve Board. If requested by the Lender, the Borrower and
                  each Subsidiary will furnish to the Lender a statement to that
                  effect in conformity with the requirements of FR Form U-1 or
                  such other similar form referred to in Regulation T,
                  Regulation U or Regulation X of the Federal Reserve Board, as
                  the case may be,

         (c)      NOTICE OF EVENT OF DEFAULT. The Borrower shall deliver to the
                  Lender promptly, and in any event within five Business Days
                  after a responsible officer of the Borrower or any
                  Subsidiaries becoming aware of the existence of any Event of
                  Default, a written notice specifying the nature and period of
                  existence thereof and what action the Borrower is taking or
                  proposes to take with respect thereto;

         (d)      REQUESTED INFORMATION. The Borrower shall deliver to the
                  Lender as promptly as practicable such data and information
                  (including copies of periodic financial statements) relating
                  to the business, operations, affairs, financial condition,
                  assets or properties of the Borrower or any of the
                  Subsidiaries or relating to the ability of the Borrower or any
                  of its Subsidiaries to perform their respective obligations
                  hereunder, or with respect to any Loan, as from time to time
                  may be reasonably requested by the Lender.

         (e)      COMPLIANCE WITH LAWS. The Borrower shall, and shall cause its
                  Subsidiaries at all times to:

                  (i)      comply in all material respects with all Requirements
                           of Law applicable to Borrower or its Subsidiaries, as
                           the case may be; and

                  (ii)     obtain, effect and maintain in full force and effect
                           all material governmental and regulatory consents,
                           licenses, exemptions, clearances, filings,
                           registrations and authorizations necessary for the
                           conduct of the business, trade and ordinary
                           activities of the Borrower and its Subsidiaries.

         (f)      INSURANCE. The Borrower shall maintain, and cause each
                  Subsidiary to maintain, insurance on and in relation to its
                  business and assets against such risks and to such extent as
                  it reasonably considers good business practice for companies
                  carrying on a business such as that carried on by the relevant
                  Person.

         (g)      LIMITATIONS ON INDEBTEDNESS. The Borrower shall not, and shall
                  not permit any of its Subsidiaries to, directly or indirectly,
                  create, incur, assume or permit to remain outstanding any
                  Indebtedness except the following ("PERMITTED INDEBTEDNESS"):

                  (i)      Indebtedness under Excluded Facilities in an
                           aggregate principal amount outstanding that does not
                           exceed 110% of the amount (in Dollars or Dollar






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<PAGE>   12




                           Equivalents) of the Indebtedness provided for in the
                           Business Plan most recently approved by the board of
                           directors of the Borrower;

                  (ii)     Indebtedness of the Borrower to any Subsidiary, or
                           Indebtedness of any Subsidiary to the Borrower or any
                           other Subsidiary;

                  (iii)    Indebtedness under currency or interest rate hedging
                           agreements;

                  (iv)     Indebtedness in respect of performance bonds,
                           bankers' acceptances and letters of credit provided
                           in the ordinary course of business; and

                  (v)      Indebtedness to renew, extend, refinance or replace
                           any Indebtedness permitted by this Section, PROVIDED
                           that such Indebtedness does not exceed the principal
                           amount of and premium, if any, on the Indebtedness
                           being renewed, extended, refinanced or replaced, plus
                           reasonable costs and expenses incurred upon such
                           renewal, extension, refinancing or replacement.

         (h)      LIMITATIONS ON INVESTMENTS. The Borrower shall not, and shall
                  not permit any Subsidiary to, purchase, own, invest in or
                  otherwise acquire, directly or indirectly, any capital stock,
                  interests in any partnership or joint venture, evidence of
                  indebtedness or other obligation or security, substantially
                  all or a material portion of the business or assets of any
                  other Person or any other investment or interest whatsoever in
                  any other Person, or make or permit to exist, directly or
                  indirectly, any loans, advances or extensions of credit to, or
                  any investment in cash or by delivery of property in, any
                  Person (each of the foregoing, an "INVESTMENT"), or enter
                  into, directly or indirectly, any commitment or option in
                  respect of any Investment except:

                  (i)      Permitted Investments;

                  (ii)     Investments in the Borrower or its Subsidiaries; and

                  (iii)    other Investments not exceeding $5,000,000 (or the
                           Dollar Equivalents) in the aggregate.

         (i)      LIMITATIONS ON LIENS. The Borrower shall not, and shall not
                  permit any Subsidiary to, create or have outstanding any Lien
                  on or over any assets, except for:

                  (i)      Permitted Liens; and






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                  (ii)     other Liens created or outstanding on or over assets
                           of the Borrower or any Subsidiary not at any time
                           exceeding $10,000,000 (or the Dollar Equivalents) in
                           the aggregate;

         (III)    PROVIDED that the Borrower shall not, and shall not permit any
                  Subsidiary to, create or have outstanding any Lien on any
                  shares of capital stock or other equity interest of such
                  Person's Subsidiaries owned by such Person.

         (j)      ASSET SALES. The Borrower shall not, and shall not permit any
                  Subsidiary to, sell, lease, assign, transfer or otherwise
                  dispose of any of its property, business or assets, including,
                  without limitation, the sale of any receivables or leasehold
                  interests and any sale-leaseback or similar transaction (each
                  of the foregoing transactions, an "ASSET SALE"), whether now
                  or hereafter acquired except:

                  (i)      the sale of inventory, equipment or services to
                           customers in the ordinary course of business;

                  (ii)     the sale of obsolete assets no longer used or usable
                           in the business of the Group;

                  (iii)    the sale or discount without recourse of receivables
                           arising in the ordinary course of business in
                           connection with the compromise or collection thereof;

                  (iv)     the transfer by any Subsidiary of any of its property
                           to any other Subsidiary or to the Borrower; and

                  (v)      other Asset Sales not exceeding $5,000,000 (or the
                           Dollar Equivalents) in the aggregate.

         (k)      CAPITAL EXPENDITURES. The Borrower shall not, and shall not
                  permit any Subsidiary to, make any Capital Expenditure in any
                  month that would cause the aggregate of all Capital
                  Expenditures of Borrower in such month to exceed an amount
                  equal to 110% of the level of Capital Expenditures of Borrower
                  provided for in the most recently delivered Business Plan with
                  respect to such month.

         (l)      PAYMENT OF TAXES. The Borrower and each of the Subsidiaries
                  shall duly and timely file or cause to be duly and timely
                  filed all tax returns which are required to be filed and shall
                  duly and timely pay all taxes shown to be due and payable on
                  such returns or on any assessments made against it or any of
                  its property by a government authority or otherwise payable by
                  it (other than any amount the validity of which is contested
                  in good faith by appropriate proceedings and with respect to




                                       11
<PAGE>   14





                  which adequate reserves are established in the books of the
                  Borrower or the Subsidiaries, as the case may be) except to
                  the extent that failure to comply with this paragraph would
                  not reasonably be expected to have a Material Adverse Effect.

11.   EVENTS OF DEFAULT.

      The Events of Default in this Agreement are:

         (a)      failure by the Borrower to make, or to cause an applicable
                  Borrowing Subsidiary to make, any repayment of principal on
                  any Loan, for more than three Business Days after such
                  principal becomes due and payable, whether at maturity or at a
                  date fixed for prepayment pursuant to Section 3(b), Section
                  3(c) or Section 3(d); or

         (b)      failure by the Borrower or any Borrowing Subsidiary to make
                  payment of any interest on any Loan for more than three
                  Business Days after such interest becomes due and payable; or

         (c)      the Borrower or any Borrowing Subsidiary defaults in its
                  performance of or compliance with any other term contained
                  herein (other than those referred to in paragraphs (a) or (b)
                  of this Section) and such default is not remedied within 30
                  days after the earlier of (I) an officer of the Borrower or
                  such Borrowing Subsidiary, as the case may be, obtaining
                  actual knowledge of such default and (II) the Borrower or such
                  Borrowing Subsidiary, as the case may be, receiving written
                  notice of such default from the Lender (any such notice to be
                  identified as a "notice of default" and to refer specifically
                  to this paragraph (c) of Section 11); or

         (d)      (I) the Borrower or any Subsidiary is in default (as principal
                  or as guarantor or other surety) in the payment of any
                  principal of or premium or make-whole amount or interest on
                  any indebtedness for borrowed money that is outstanding in an
                  aggregate principal amount of at least $5,000,000 (or the
                  Dollar Equivalents) beyond any period of grace provided with
                  respect thereto, or (II) the Borrower or any Subsidiary is in
                  default in the performance of or compliance with any material
                  term of any evidence of any indebtedness for borrowed money in
                  an aggregate outstanding principal amount of at least
                  $5,000,000 (or the Dollar Equivalents) or of any mortgage,
                  indenture or other agreement relating thereto or any other
                  condition exists, and as a consequence of such default or
                  condition such indebtedness has become, or has been declared
                  due and payable before its stated maturity or before its
                  regularly scheduled dates of payment; or





                                       12
<PAGE>   15




         (e)      the Borrower or any Subsidiary (I) is generally not paying, or
                  admits in writing its inability to pay, its debts as they
                  become due, (II) files, or consents by answer or otherwise to
                  the filing against it of, a petition for relief or
                  reorganization or arrangement or any other petition in
                  bankruptcy, for liquidation or to take advantage of any
                  bankruptcy, insolvency, reorganization, moratorium or other
                  similar law of any jurisdiction, (III) makes as assignment for
                  the benefit of its creditors, (IV) consents to the appointment
                  of a custodian, receiver, trustee or other officer with
                  similar powers with respect to it or with respect to any
                  substantial part of its property, (V) is adjudicated as
                  insolvent or to be liquidated, or (VI) takes action for the
                  purpose of any of the foregoing; or

         (f)      a court or governmental authority of competent jurisdiction
                  enters an order appointing, without consent by the Borrower or
                  any Subsidiary, a custodian, receiver, trustee or other
                  officer with similar powers with respect to it or with respect
                  to any substantial part of its property, or constituting an
                  order for relief or approving a petition for relief or
                  reorganization or any other petition in bankruptcy or for
                  liquidation or to take advantage of any bankruptcy or
                  insolvency law of any jurisdiction, or ordering the
                  dissolution, winding-up or liquidation of the Borrower or any
                  Subsidiary or any such petition shall be filed against the
                  Borrower or any Subsidiary and such petition shall not be
                  dismissed within 60 days; or

         (g)      a final judgment or judgments for the payment of money
                  aggregating in excess of $3,000,000 (or the Dollar
                  Equivalents) are rendered against the Borrower or any
                  Subsidiary and which judgments are not, within 60 days after
                  entry thereof, bonded, discharged or stayed pending appeal, or
                  are not discharged within 60 days after the expiration of such
                  stay; or

         (h)      revocation or non-renewal of any license, concession or
                  similar authorization that is material to the business of the
                  Group as currently conducted or planned to be conducted in
                  accordance with the most recently delivered Business Plan; or

         (i)      expropriation or nationalization of any material assets,
                  business or business unit of the Borrower or any Subsidiary,
                  or any state of war or political conflict or imposition of any
                  restriction on currency convertibility or transferability of
                  funds that is reasonably likely to have a Material Adverse
                  Effect.

12.   REMEDIES UPON DEFAULT, ETC.

         (a)      If any Event of Default referred to in Section 11 shall have
                  occurred and be continuing, (X) upon the occurrence of any
                  such Event of Default described in clauses (e) or (f) of
                  Section 11, the whole amount of the outstanding Loans and all
                  accrued interest and other amounts owing thereunder shall





                                       13
<PAGE>   16





                  automatically become due and payable, or (Y) upon the
                  occurrence of any other Event of Default described in Section
                  11, the Lender may at anytime at its option, by demand in
                  writing to the Borrower, declare the whole amount of the
                  outstanding Loan to be immediately due and payable.

         (b)      Upon any portion of the Loans becoming due and payable under
                  this Section 12, whether automatically or by declaration, the
                  entire unpaid principal amount of the Loans plus all accrued
                  and unpaid interest thereon, shall all be immediately due and
                  payable, in each and every case without presentment, demand,
                  protest or further notice, all of which are hereby waived.

         (c)      OTHER REMEDIES. If any Event of Default has occurred and is
                  continuing, and irrespective of whether the Loan has become or
                  has been declared immediately due and payable under this
                  Section, the Lender may at the time that the Loan is
                  outstanding, proceed to protect and enforce the rights of such
                  holder by an action at law, suit in equity or other
                  appropriate proceeding, whether for the specific performance
                  of any agreement contained herein, or for an injunction
                  against a violation of any of the terms hereof or thereof, or
                  in aid of the exercise of any power granted hereby or thereby
                  or by law or otherwise.

         (d)      NO WAIVERS OR ELECTION OF REMEDIES, EXPENSES, ETC. No course
                  of dealing and no delay on the part of the Lender in
                  exercising any right, power or remedy shall operate as a
                  waiver thereof or otherwise prejudice the Lender's rights,
                  powers or remedies. No right, power or remedy conferred by
                  this Agreement upon the Lender shall be exclusive of any other
                  right, power or remedy referred to herein or therein or now or
                  hereafter available at law, in equity, by statute or
                  otherwise. The Borrower will pay to the Lender on demand such
                  further amount as shall be sufficient to cover all costs and
                  expenses of such holder incurred in any enforcement or
                  collection under this Section 12, including, without
                  limitation, reasonable attorneys' fees, expenses and
                  disbursements.

13.   WITHHOLDING.

         (a)      Except as otherwise required under applicable law, all
                  payments made by the Borrower or any Borrowing Subsidiary
                  hereunder will be made free and clear of, and without
                  deduction or withholding for or on account of, any present or
                  future Taxes. If any such Taxes are required to be deducted or
                  withheld, the Borrower shall make the required deduction and
                  will timely remit to the relevant tax authority the amount so
                  deducted. The Borrower will furnish to the Lender, within 15
                  days after the date the payment of any withholding Taxes in





                                       14
<PAGE>   17



                  respect of payments hereunder is due pursuant to applicable
                  law, certified copies of tax receipts (if available)
                  evidencing such payment by the Borrower or the applicable
                  Borrowing Subsidiary.

         (b)      The Borrower and each Borrowing Subsidiary shall pay, and
                  shall jointly and severally indemnify and hold harmless the
                  Lender and reimburse the Lender upon its written request, for
                  any bank charges, capital circulation charges, stamp,
                  transfer, court or documentary taxes, CMPF or other financial
                  transaction taxes or any other excise or property taxes,
                  charges or similar levies imposed by any jurisdiction in
                  connection with the execution, delivery, enforcement or
                  performance of this Agreement.

14.   INCREASED COSTS.

      If the Lender determines that, as a result of the introduction of or any
      change in, or in the interpretation or application of, any law or
      directive after the date of this Agreement:

         (i)      it incurs a cost in maintaining all or part of any Loan except
                  for its own costs of borrowing; and/or

         (ii)     any sum received or receivable by it under this Loan Agreement
                  or the effective return to it under this Loan Agreement or the
                  overall return on its capital is reduced (except on account of
                  Tax on its overall net income); and/or

         (iii)    it makes any payment (except on account of Tax on its overall
                  net income) or forgoes any interest or other return on or
                  calculated by reference to the amount of any sum received or
                  receivable by it under this Agreement,

      the Borrower and each Borrowing Subsidiary jointly and severally shall
      indemnify it against that cost, reduction, payment or forgone interest or
      other return (except to the extent that it results from a deduction or
      withholding of Tax) and, accordingly, shall from time to time on demand
      (whenever made) pay to the Lender the amount certified by it to be
      necessary so to indemnify it. For the avoidance of doubt, the
      indemnification referred to in the preceding sentence shall apply to such
      Regulation D costs, if any, as may be applied to the Lender from time to
      time.

15.   INDEMNITIES.

         (a)      MISCELLANEOUS INDEMNITIES. The Borrower and each Borrowing
                  Subsidiary shall jointly and severally on demand indemnify the
                  Lender against any funding or other cost, loss, expense or
                  liability sustained or incurred by it as a result of:



                                       15
<PAGE>   18


                  (i)      the Loan not being made by reason of the Borrower
                           purporting to revoke any Borrowing Notice;

                  (ii)     the occurrence or continuance of any Event of
                           Default; or

                  (iii)    the receipt or recovery by any party of all or any
                           part of the Loan or overdue sums otherwise than on
                           the date such amount is due or the Interest Payment
                           Date.

         (b)      TRANSACTION INDEMNITY.

                  (i)      The Borrower and each Borrowing Subsidiary shall
                           indemnify and hold the Lender and its respective
                           directors, officers, agents and affiliates (the
                           "INDEMNIFIED PARTIES") harmless from and against any
                           and all claims, damages, liabilities, taxes, costs
                           and expenses (including reasonable legal fees, travel
                           and other expenses and disbursements) which may be
                           incurred by or asserted against the Indemnified
                           Parties in connection with or arising out of any
                           investigation, litigation or proceeding relating to
                           this Agreement (except for any arising out of any
                           Indemnified Party's gross negligence or willful
                           default) whether or not the Indemnified Parties are
                           parties thereto, and will pay all costs and expenses
                           of the Indemnified Parties (including all reasonable
                           legal and proper fees, expenses and disbursements)
                           incurred or sustained by the Indemnified Parties in
                           connection with the same whether or not the Loan is
                           utilized.

                  (ii)     Any party that proposes to assert the right to be
                           indemnified under this Section will, promptly after
                           receipt of notice of commencement of any action, suit
                           or proceeding against such party in respect of which
                           a claim is to be made against the Borrower under this
                           Section notify the Borrower of the commencement of
                           such action, suit or proceeding, enclosing a copy of
                           all papers served, but the omission so to notify the
                           Borrower of any such action, suit or proceeding shall
                           not relieve the Borrower from any liability that it
                           may have to any Indemnified Party unless the Borrower
                           is effectively precluded from exercising any of its
                           material rights to contest such claim as a result of
                           such omission to notify.

                  (iii)    In case any such action, suit or proceeding shall be
                           brought against any Indemnified Party and
                           notification has been made to the Borrower of the
                           commencement thereof, the Borrower shall be entitled
                           to participate in such action, suit or proceeding.




                                       16
<PAGE>   19




         (c)      INDEMNITIES SEPARATE. Each of the Indemnities in this
                  Agreement constitutes a separate and independent obligation
                  from the other obligations in this Agreement, shall give rise
                  to a separate and independent cause of action, shall apply
                  irrespective of any indulgence granted by the Lender and shall
                  continue in full force and effect despite any judgment, order,
                  claim or proof for a liquidated amount in respect of any sum
                  due under this Agreement or any other judgment or order.

16.   CHANGE IN MARKET CONDITIONS.

         (a)      LIBOR. If in relation to any Interest Period, the Lender is
                  unable to determine the LIBOR Rate, the Lender shall promptly
                  notify the Borrower and the Loan shall not be made.

         (b)      NEGOTIATION. The Borrower and the Lender shall then negotiate
                  until not more than 25 days after such determination by the
                  Lender with a view to agreeing an alternative basis for
                  calculating the interest payable on and/or funding the
                  affected Loan or Loans. Any alternative basis agreed in
                  writing by the Lender and the Borrower within that 25 day
                  period shall take effect in accordance with its terms.

         (c)      SUBSTITUTE INTEREST RATE. If an alternative basis for
                  calculating the interest payable is not agreed in writing
                  pursuant to Section 16(b), the Loan shall during that Interest
                  Period bear interest at the rate per annum equal to the sum of
                  the Mandatory Costs and the cost to the Lender (expressed as a
                  rate per annum) of funding the Loan during that Interest
                  Period by whatever means it determines to be appropriate. The
                  Lender shall certify that cost to the Borrower as soon as
                  practical after the Lender's determination of the event in
                  question (but in any event at least two Business Days before
                  the end of that Interest Period).

17.   DEFINITIONS.

      "AFFILIATE" means, with respect to any Person, a Person that directly or
      indirectly through one or more intermediaries, controls, is controlled by,
      or is under common control with, the first Person. "control" means the
      possession, directly or indirectly, of the power to direct or cause the
      direction of the management policies of a Person, whether through the
      ownership of voting securities, by contract or credit arrangement, as
      trustee or executor, or otherwise.

      "AGGREGATE COMMITMENT" has the meaning set forth in the Recitals.

      "AGREEMENT" has the meaning set forth in the Preamble hereto.






                                       17
<PAGE>   20



      "ASSET SALE" has the meaning set forth in Section 10(j).

      "BORROWER" has the meaning set forth in the Preamble hereto.

      "BORROWING NOTICE" has the meaning set forth in Section 2(a).

      "BUSINESS DAY" means any day other than a Saturday, Sunday or day on which
      commercial banking institutions are authorized or required by law,
      regulation or executive order to be closed in New York, New York or
      London, United Kingdom.

      "BUSINESS PLAN" has the meaning set forth in Section 10(a).

      "CAPITAL EXPENDITURES" means, for any Person for any period, the sum of
      all expenditures made, directly or indirectly, by such Person or any of
      its Subsidiaries during such period for equipment, assets, real property
      or improvements, or for replacements or substitutions therefor or
      additions thereto, that would in accordance with U.S. Generally Accepted
      Accounting Principles be reflected as additions to property, plant or
      equipment on a consolidated balance sheet of such Person.

      "CODE" means the Internal Revenue Code of 1986, as amended from time to
      time, and the rules and regulations promulgated thereunder from time to
      time.

      "DOLLARS" and "$"  mean lawful currency of the United States of America.

      "DOLLAR EQUIVALENT" means with respect to any amount denominated in a
      foreign currency, at any date of determination thereof, an amount in
      Dollars equivalent to such amount calculated on the basis of the Spot Rate
      of Exchange.

      "EVENT OF DEFAULT" means one of the events mentioned in Section 11.

      "EXCLUDED FACILITIES" means (I) local credit facilities of Subsidiaries,
      denominated in Dollars or in local currency or units, primarily to finance
      working capital requirements, and (II) Vendor Financing Facilities.

      "GROUP" means, at any particular time, the Borrower and its Subsidiaries
      (and "member of the Group" shall be construed accordingly).

      "INDEBTEDNESS" of any Person at any date, means all indebtedness of such
      Person for borrowed money or for the deferred purchase price of property
      or services (other than trade liabilities incurred in the ordinary course
      of business and payable in accordance with customary practices),
      obligations under capital leases appearing or required to appear on the
      balance sheet of such Person and any other indebtedness of such Person
      which is evidenced by a note, bond, debenture or similar instrument.






                                       18
<PAGE>   21




      "INDEMNIFIED PARTIES" has the meaning set forth in Section 15(b).

      "INTEREST PERIOD" has the meaning set forth in Section 5(b).

      "INVESTMENTS" has the meaning set forth in Section 10(h).

      "LENDER" has the meaning set forth in the Preamble.

      "LIBOR RATE" has the meaning set forth in Section 5(e).

      "LIEN" means, with respect to any Person, any lien, pledge, charge,
      security interest, encumbrance or any interest or title of any vendor,
      lessor, lender or other secured party to or of such Person.

      "LOAN" has the meaning set forth in Section 1.

      "MANDATORY COSTS" means, in relation to any Interest Period (or part of an
      Interest Period) relating to a Loan or overdue sum, the percentage rate
      per annum determined by the Lender.

      "MARGIN" has the meaning set forth in Section 5(e).

      "MATERIAL ADVERSE EFFECT" has the meaning set forth in Section 9(b).

      "NEW YORK COURTS" has the meaning set forth in Section 18.

      "NOTE" has the meaning set forth in Section 4.

      "PERMITTED INDEBTEDNESS" has the meaning set forth in Section 10(g).

      "PERMITTED INVESTMENTS" means:

         (i) marketable obligations maturing within one year or less after
      acquisition thereof, issued or guaranteed by the United States of America
      or an instrumentality or agency thereof;

         (ii) certificates of deposit, maturing within one year after
      acquisition thereof, or open market commercial paper maturing within 270
      days after acquisition thereof, in each case issued by a bank organized in
      the United States of America having capital, surplus and undivided profits
      as of December 31, 1999 of at least $1,000,000,000 and having a commercial
      paper rating of A-1 or P-1;





                                       19
<PAGE>   22



         (iii) Investments in any Person received solely in consideration for
      the issuance by the Borrower of its capital stock, PROVIDED that after
      giving effect to such Investment on a historical pro forma basis there
      would not be any breach of Section 10(g) or any other covenant contained
      herein;

         (iv) trade credit extended to customers of any member of the Group in
      the ordinary course of business;

         (v) guaranties and similar support arrangements relating to Permitted
      Indebtedness; or

         (vi) advances to officers and employees for travel and other business
      expenses.

      "PERMITTED LIENS" means:

         (i) Liens securing any Loan;

         (ii) Liens to secure obligations under any of the 14% Senior Notes due
      2007 issued by FirstCom Corporation remaining outstanding after the date
      hereof.

         (ii) Liens in favor of the Borrower;

         (iii) Liens on property of any Person existing at the time such Person
      is acquired by or merged or consolidated with any member of the Group,
      PROVIDED that such Liens were not created in contemplation of such
      acquisition, merger or consolidation and do not extend to any assets other
      than those of such Person;

         (iv) statutory Liens of landlords and statutory Liens of carriers,
      warehousemen, mechanics and materialmen incurred in the ordinary course of
      business;

         (v) Liens to secure the performance of statutory obligations, surety or
      appeal bonds, performance bonds or similar obligations incurred in the
      ordinary course of business;

         (vi) Liens in connection with Vendor Financing Facilities;

         (vii) Liens for Taxes, assessments or governmental charges or claims
      that are not yet delinquent or that are being contested in good faith by
      appropriate proceedings; or

         (vii) renewals or replacements of any Liens referred to above.





                                       20
<PAGE>   23




      "PERSON" means any individual, corporation, company, limited liability
      company, association, partnership, trust, estate, governmental authority
      or other entity.

      "REGULATION D COSTS" means any costs under Regulation D of the Board of
      Governors of the United States Federal Reserve System.

      "REQUIREMENT OF LAW" means, as to any Person, the certificate of
      incorporation and by-laws or other organizational or governing documents
      of such Person, and any law, statute, ordinance, code, decree, treaty,
      rule or regulation or determination of an arbitrator or a court or other
      governmental authority, in each case applicable to or binding upon such
      Person or any of its property or assets or to which such Person or any of
      its property or assets are subject; provided that the foregoing shall not
      apply to any non-binding recommendation of any governmental authority.

      "SPOT RATE OF EXCHANGE," with respect to any foreign currency, at any date
      of determination thereof, means the spot rate of exchange in London that
      appears on the display page applicable to such foreign currency on the Dow
      Jones Market Service (or such other page as may replace such page for the
      purpose of displaying the spot rate of exchange in London); PROVIDED that
      if there shall at any time no longer exist such a page, the spot rate of
      exchange shall be determined in reference to another similar rate
      publishing service selected by Lender.

      "SUBSIDIARY" means any Person in which a Person owns or controls, directly
      or indirectly, capital stock or other equity interests representing more
      than 50% of the outstanding voting stock or other equity interests of such
      Person and representing more than 50% of the voting rights attaching
      thereto.

      "TAX" or "TAXES" means any income, franchise, gross receipts, sales,
      rental, use, value-added, turnover, excise, property, user, capital, doing
      business, transfer, stamp or other taxes.

      "TERMINATION DATE" means the earliest to occur of (i) the final maturity
      date specified in Section 3(a), and (ii) any date on which the Aggregate
      Commitment has been reduced to zero pursuant to Section 3(g).

      "VENDOR FINANCING FACILITY" means any credit facilities of any member of
      the Group to finance the purchase or use of equipment, software and/or
      services provided by the vendors thereof, PROVIDED such facility is not
      secured by any assets other than the assets acquired from such vendor or
      vendors by Borrower or its Subsidiaries in connection with such facility
      as permitted by this Agreement.




                                       21
<PAGE>   24




18.   APPLICABLE LAW/SUBMISSION TO JURISDICTION.

      This Agreement shall be governed by and construed in accordance with the
      law of the State of New York. Each of the parties hereto hereby
      irrevocably and unconditionally consents to submit to the exclusive
      jurisdiction of the courts of the State of New York and of the United
      States of America located in the State of New York (the "NEW YORK COURTS")
      for any litigation arising out of or relating to this Agreement and the
      transactions contemplated hereby (and agrees not to commence any
      litigation relating thereto except in such courts), waives any objection
      to the laying of venue of any such litigation in the New York Courts and
      agrees not to plead or claim in any New York Court that such litigation
      brought therein has been brought in an inconvenient forum.

19.   ASSIGNMENT.

      None of the parties hereto may assign or otherwise transfer any of its
      rights under this Agreement, except that Lender may assign this Agreement,
      and all or any portion of any Note or Notes, to an any Affiliate of AT&T
      Corp.

20.   COUNTERPARTS.

      This Agreement may be executed by the parties hereto in separate
      counterparts, each of which when so executed and delivered shall be an
      original, but all such counterparts shall together constitute on and the
      same instrument. Each counterpart may consist of a number of copies hereof
      each signed by less than all, but together signed by all, of the parties
      hereto.




                                       22
<PAGE>   25


      In witness whereof, the parties hereto have executed this Agreement and
      caused the same to be delivered on their behalf as of the date first
      written above.

Witness                                              Global Card Holdings Inc.
       -----------------------
       Name:
Witness:                                             By:
        ----------------------                          -----------------------
        Name:                                           Name:
                                                        Title:


Witness                                              AT&T Latin America Corp.
       -----------------------
       Name:
Witness:                                             By:
        ----------------------                          -----------------------
        Name:                                           Name:
                                                        Title:


Witness                                              Netstream Telecom Ltda.
       -----------------------
       Name:
Witness:                                             By:
        ----------------------                          -----------------------
        Name:                                           Name:
                                                        Title:


Witness                                              Keytech LD S.A.
       -----------------------
       Name:
Witness:                                             By:
        ----------------------                          -----------------------
        Name:                                           Name:
                                                        Title:


                                       23
<PAGE>   26


                                                                    Schedule A



      Netstream Telecom Ltda.

      Keytech LD S.A.


<PAGE>   27




                            FORM OF BORROWING REQUEST

To:   Global Card Holdings Inc.

           The undersigned, AT&T Latin America Corp. (the "BORROWER"), refers to
the Credit Facility Agreement, dated as of [_________ __], 2000 (as amended,
supplemented or otherwise modified from time to time, the "AGREEMENT"), among
Global Card Holdings Inc., (the "LENDER"), Borrower and certain Subsidiaries of
Borrower.

           Capitalized terms used herein and not otherwise defined herein shall
have the meanings assigned to such terms in the Agreement.

1.   Loan.

         The Borrower hereby gives you notice pursuant to Section 2(a) of the
         Agreement that it requests a Loan subject to and in accordance with the
         terms of the Agreement and in that connection sets forth below the
         terms on which such Loan is requested to be made:

         (a) Aggregate Principal Amount of Loan: $______________________

         (b) Borrowing Breakdown:
<TABLE>
<CAPTION>

        ---------------------------------- ---------------------------- --------------------------------
                    Borrower                     Amount of Borrowing           Date of Borrowing
          [and Borrowing Subsidiaries]              (in Dollars)           (which is a Business Day)
        ---------------------------------- ---------------------------- --------------------------------
<S>                                        <C>                                 <C>
        AT&T Latin America Corp.           $
                                            -----------------                  ---------------------
        Proposed Borrowing Subsidiaries:


                                           $
             -----------------              -----------------                  ---------------------

                                           $
             -----------------              -----------------                  ---------------------

                                           $
             -----------------              -----------------                  ---------------------

                                           $
             -----------------              -----------------                  ---------------------

                                           $
             -----------------              -----------------                  ---------------------
        ---------------------------------- ---------------------------- --------------------------------
        Total                              $                                   N/A
                                            -----------------
        ---------------------------------- ---------------------------- --------------------------------
</TABLE>



<PAGE>   28


(c)   Funds are requested to be disbursed to the Borrower's [or Borrowing
      Subsidiary's] account with:

----------------------------------------- -------------------------------------
 Borrower [and Borrowing Subsidiaries]             Account Information
----------------------------------------- -------------------------------------
                                          Bank Name: ___________________

AT&T Latin America Corp                   Bank Address:__________________

                                          Account Number: _______________
----------------------------------------- -------------------------------------
                                          Bank Name: ___________________

______________________                    Bank Address:__________________

                                          Account Number: _______________
----------------------------------------- -------------------------------------
                                          Bank Name: ___________________

______________________                    Bank Address:__________________

                                          Account Number: _______________
----------------------------------------- -------------------------------------
                                          Bank Name: ___________________

______________________                    Bank Address:__________________

                                          Account Number: _______________
----------------------------------------- -------------------------------------
                                          Bank Name: ___________________

_______________________                   Bank Address:__________________

                                          Account Number: _______________
----------------------------------------- -------------------------------------
                                          Bank Name: ___________________

________________________                  Bank Address:__________________

                                          Account Number: _______________
----------------------------------------- -------------------------------------





<PAGE>   29



2.   CERTIFICATIONS.

     As of the date hereof and as of each "Date of Borrowing" listed in 1(b):

         (a)      the Borrower and Borrowing Subsidiaries have performed and
                  complied with all the respective terms and conditions of the
                  Agreement applicable to them;

         (b)      there exists or will exist after giving effect to any Loan
                  requested hereunder no condition or event which constitutes or
                  which, after notice or passage of time or both, would
                  constitute an Event of Default;

         (c)      each of the representations and warrants contained in Section
                  9 of the Agreement are, and will be after giving effect to any
                  Loan requested hereunder, true and correct; and

         (d)      the amounts of the Loan specified in this Borrowing Notice is
                  consistent with the Business Plan most recently delivered to
                  the Lender.

                                               AT&T Latin America Corp.

                                               By:
                                                  ----------------------------
                                                     Name:
                                                     Title: (CEO or CFO)

Date:
     --------------------

<PAGE>   30


                                 PROMISSORY NOTE

$ [                         ]                           Date ________ __, 200_

      For value received, [AT&T Latin America Corp. ("BORROWER")][[Insert Name
of Borrowing Subsidiary if applicable] (the "BORROWING SUBSIDIARY")] hereby
promises to pay to the order of Global Card Holdings Inc. ("LENDER") on [July
__, 2000 or, if FirstCom Corporation has merged with a subsidiary of AT&T Latin
America, the second annual anniversary of the date of consummation of such
merger (or if such date is not a Business Day, the next succeeding Business
Day)] in lawful money of the United States of America to an account specified in
writing by Lender, the principal sum of [ ] together with interest at the rate
per annum specified in the Credit Facility Agreement, dated [ ], 2000 among
Lender, Borrower and certain subsidiaries of Borrower (as amended, supplemented
or otherwise modified from time to time, the "AGREEMENT") in accordance with the
terms and conditions of such Agreement.

      Each capitalized term not otherwise defined in this Note shall have the
meaning set forth in the Agreement.

      This Note represents a Loan under the Agreement and is governed by the
terms thereof, including, without limitation, with respect to the rights of
Lender in the case of any security that may be provided to Lender by the
Borrower or any Borrowing Subsidiary from time to time pursuant to Section 8 of
the Agreement. In case an Event of Default, as defined in the Agreement, shall
occur and be continuing, the unpaid balance of the principal of this Note may be
declared and become due and payable in the manner and with the effect provided
in the Agreement.

      This Note shall be governed by, and construed in accordance with, the laws
of the State of New York.

      This Note may not be assigned except in accordance with the Agreement.

                            [AT&T LATIN AMERICA CORP.

                            By:______________________________________________

                            Title:___________________________________________ ]

                            [BORROWING SUBSIDIARY

                            By:______________________________________________

                            Title:___________________________________________ ]

         [Customary Legends, Witnesses, etc. to be added to comply with local
law of any Borrowing Subsidiary]