EXHIBIT 10.25

                                                                  EXECUTION COPY

                              AMENDMENT AND CONSENT

                  AMENDMENT AND CONSENT, dated as of March 30, 2001, to the
CREDIT AGREEMENT, dated as of July 2, 1998 (the "Credit Agreement"), among
Teligent, Inc., a Delaware corporation (the "Borrower"), the Lenders from time
to time parties thereto, Goldman Sachs Credit Partners L.P., as Syndication
Agent, Toronto Dominion (Texas), Inc., as Documentation Agent, and The Chase
Manhattan Bank, as Administrative Agent.

                              W I T N E S S E T H :
                               - - - - - - - - - -

                  WHEREAS, each of the Lenders is a party to the Credit
Agreement pursuant to which the Borrower may borrow from time to time Optional
Term Loans in an aggregate face amount of up to $400,000,000 (the "Original
Optional Term Facility Amount"); and

                  WHEREAS, the Borrower wishes to increase the Original Optional
Term Facility Amount from $400,000,000 up to $600,000,000 (as so increased, the
"New Optional Term Facility Amount"); and

                  WHEREAS, the Borrower wishes to utilize a portion, not in
excess of $350,000,000, of the New Optional Term Facility Amount as an optional
vendor financing facility; and

                  WHEREAS, the Borrower wishes to allow certain vendors to the
Borrower to become parties to the Credit Agreement from time to time after the
Effective Date (as defined below) until December 31, 2001; and

                  WHEREAS, the parties have agreed to modify certain of the
covenants and other terms in the Credit Agreement as set forth herein;

                  NOW, THEREFORE, the Borrower, the Administrative Agent, and
the Required Prepayment Lenders hereby agree as follows:

                  1.    Defined Terms.  Capitalized terms used herein without
definition shall have the meaning ascribed to such terms in the Credit
Agreement.

                  2.    Amendment to Section 1.1 - Defined Terms.  (a)  The
following definitions are hereby amended so that they shall read in their
entirety respectively as follows:

                  "Applicable Margin": (a) for Tranche A Term Loans, Delayed
                  Draw Term Loans, Conversion Term Loans and Revolving Credit
                  Loans, 4.50% per annum, in the case of Eurodollar Loans, and
                  3.50%, in the case of ABR Loans, and (b) for each Type of
                  Optional Term Loans of each Tranche, the rate per annum for
                  such Tranche and Type determined in accordance with the
                  Optional Term Loan Amendment executed for such Tranche
                  pursuant to Section 2.7.

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                  "Asset Sale": (i) any Disposition of Non-Core Assets
                  (excluding any such Disposition permitted by clause (a), (b),
                  (d), (e) or (g) of Section 6.5) and (ii) the entering into of
                  one or more management agreements with respect to spectrum by
                  any Restricted Subsidiary to any Unrestricted Subsidiary or
                  other Person; provided, that such agreements are (A) compliant
                  with all material terms of this Agreement as determined by the
                  Administrative Agent in good faith (including, without
                  limitation, that all Net Cash Proceeds of such management
                  agreement shall be applied in accordance with Section 2.13)
                  and (B) reasonably satisfactory in form and substance to FCC
                  counsel to the Lenders.

                  "Consolidated Cash Interest Expense": for any fiscal quarter,
                  total cash interest expense (including that attributable to
                  Capital Lease Obligations) of the Borrower and its Restricted
                  Subsidiaries to be paid during such fiscal quarter (including,
                  without limitation, all commissions, discounts and other fees
                  and charges owed with respect to letters of credit and
                  bankers' acceptance financing and net costs under hedge
                  agreements in respect of interest rates to the extent such net
                  costs are allocable to such fiscal quarter in accordance with
                  GAAP) as reasonably determined by the Borrower on the basis of
                  (i) the aggregate amount of Indebtedness of the Borrower and
                  its Restricted Subsidiaries outstanding on the first day of
                  such fiscal quarter and (ii) interest rates applicable to such
                  Indebtedness on such date.

                  "Consolidated Fixed Charge Coverage Ratio": (a) from the
                  Amendment Effective Date through the fiscal quarter ending
                  September 30, 2003, on the last day of any fiscal quarter, the
                  ratio of (i) the amount of Consolidated EBITDA required
                  pursuant to Section 6.1(k) for the fiscal quarter immediately
                  following such last day, to the extent that Consolidated
                  EBITDA for such fiscal quarter is negative, plus the sum of
                  (A) the amount of cash and Cash Equivalents held by the
                  Borrower and its Restricted Subsidiaries, (B) the Available
                  Revolving Credit Commitments, (C) the Available Tranche A Term
                  Loan Commitments, (D) the Available Delayed Draw Term Loan
                  Commitments, and (E) any available unused Optional Non-Vendor
                  Loan Commitments, in each case, determined as of such last day
                  to (ii) Consolidated Fixed Charges for the fiscal quarter
                  immediately following such last day and (b) from the fiscal
                  quarter ending December 31, 2003 and thereafter, for any
                  period of four consecutive fiscal quarters, the ratio of (i)
                  Consolidated EBITDA for such period plus the sum of (A) the
                  Available Revolving Credit Commitments, (B) the Available
                  Tranche A Term Loan Commitments, (C) the Available Delayed
                  Draw Term Loan Commitments, and (D) any available unused
                  Optional Non-Vendor Term Loan Commitments, in each case,
                  determined as of the last day of such period of four
                  consecutive fiscal quarters to (ii) Consolidated Fixed Charges
                  for such period of four consecutive fiscal quarters.

                  "Consolidated Fixed Charges": (a) from the Amendment Effective
                  Date through the fiscal quarter ending September 30, 2003, for
                  any fiscal quarter, the sum (without duplication) of (i)
                  Consolidated Cash Interest Expense for such fiscal quarter,
                  (ii) projected cash income taxes to be paid by the Borrower or
                  any of its Restricted Subsidiaries on a consolidated basis in
                  respect of such fiscal quarter, (iii) preferred dividends
                  required to be paid in cash in such fiscal quarter and (iv)

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                  scheduled payments to be made during such fiscal quarter on
                  account of principal of Indebtedness of the Borrower or any of
                  its Restricted Subsidiaries and (b) from the fiscal quarter
                  ending December 31, 2003 and thereafter, for any period of
                  four consecutive fiscal quarters, the sum (without
                  duplication) of (i) Consolidated Cash Interest Expense for
                  such period, (ii) provision for cash income taxes made by the
                  Borrower or any of its Restricted Subsidiaries on a
                  consolidated basis in respect of such period and (iii)
                  scheduled payments made during such period on account of
                  principal of Indebtedness of the Borrower or any of its
                  Restricted Subsidiaries.

                  "Consolidated Secured Debt":  all Consolidated Total Debt,
                  excluding the Convertible Notes, secured pursuant to the
                  Security Documents or by any other security interest in any
                  assets of the Borrower or any of its Restricted Subsidiaries.

                  "Default":  any of the events specified in Section 7, whether
                  or not any requirement for the giving of notice, the lapse of
                  time, or both, has been satisfied.

                  "Existing Affiliate Transactions": (a) transactions pursuant
                  to the Administrative Services Agreement, dated as of March 5,
                  1996, between the Borrower (formerly DMT, LLC) and Microwave
                  Services, Inc., a Subsidiary of Associated Group, Inc. as in
                  effect on the date hereof, and as such agreement may be
                  amended from time to time in a manner no less favorable to the
                  Lenders, (b) transactions pursuant to the Technical Services
                  Agreement, dated as of October 22, 1997, between the Company
                  and NTT America, Inc. as in effect on the date hereof, and as
                  such agreement may be amended from time to time in a manner no
                  less favorable to the Lenders, (c) transactions pursuant to
                  the Stockholders Agreement, dated as of November 26, 1997,
                  between the Borrower, NTT America, Inc. and certain other
                  stockholders of the Borrower as in effect on the date hereof
                  and as such agreement may be amended from time to time in a
                  manner no less favorable to the Lenders, (d) transactions
                  pursuant to the Shareholders Agreement, dated January 13,
                  2000, by and among Alex J. Mandl, Liberty Media Corporation,
                  Telcom-DTS Investors, L.L.C. and Microwave Services, Inc. as
                  in effect on the date hereof and as such agreement may be
                  amended from time to time in a manner no less favorable to the
                  Lenders, (e) transactions pursuant to the Joint Venture
                  Agreement, dated April 11, 2000, by and between Teligent
                  International Ltd., Telcom Ventures LLC, BA Investments, Ltd.,
                  and Argentina Telecom Holdings, Ltd. as in effect on the date
                  hereof and as such agreement may be amended from time to time
                  in a manner no less favorable to the Lenders, and (f)
                  transactions pursuant to arrangements in effect on the Closing
                  Date in an aggregate amount not to exceed $5,000,000.

                  "Facility": each of (a) the Tranche A Term Loan Commitments
                  and the Tranche A Term Loans made thereunder (the "Tranche A
                  Term Loan Facility"), (b) the Delayed Draw Term Loan
                  Commitments and the Delayed Draw Term Loans made thereunder
                  (the "Delayed Draw Term Loan Facility"), (c) the Conversion
                  Term Loans (the "Conversion Term Loan Facility"), (d) the
                  Optional Non-Vendor Loan Commitments, if any, and the Optional
                  Non-Vendor Loans made thereunder (the

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                  "Optional Non-Vendor Loan Facility"), (e) the Optional Vendor
                  Commitments, if any, and the Optional Vendor Loans made
                  thereunder (the "Optional Vendor Loan Facility") and (f) the
                  Revolving Credit Commitments and the Revolving Credit Loans
                  made thereunder (the "Revolving Credit Facility").

                  "Majority Facility Lenders": at any time, with respect to any
                  Facility, the holders of more than 50% of the aggregate unpaid
                  principal amount of the Loans outstanding under such Facility
                  plus the aggregate amount of undrawn Commitments then in
                  effect under such Facility.

                  "Optional Term Loan":  any Optional Non-Vendor Loan and any
                  Optional Vendor Loan.

                  "Optional Term Loan Commitment":  any Optional Non-Vendor Loan
                  Commitment and any Optional Vendor Commitment.

                  "Optional Term Loan Lender":  any Optional Non-Vendor Loan
                  Lender and any Optional Vendor Loan Lender.

                  "Optional Term Loan Tranche":  any Optional Non-Vendor Loan
                  Tranche and any Optional Vendor Loan Tranche.


                  "Required Lenders": at any time, the holders of more than 50%
                  of the aggregate unpaid principal amount of the Loans then
                  outstanding plus the aggregate amount of undrawn Commitments
                  (other than Optional Vendor Commitments) then in effect.

                  (b)  Section 1.1 is hereby further amended by adding thereto
the following new definitions in proper alphabetical order:

                  "Amendment Effective Date":  the "Effective Date" as defined
                  in the Amendment, dated as of March 30, 2001, to this
                  Agreement.

                  "Collateral and Securities Account":  as defined in Section
                  6.13.

                  "Convertible Notes": notes issued by the Borrower to such
                  Person or Persons as determined by the Borrower, substantially
                  in the form and having the terms set forth in Exhibit A to the
                  Amendment, dated as of March 30, 2001, to this Agreement; such
                  terms shall in any event include subordination of such notes,
                  in right of payment, to the Obligations, and subordination of
                  any security interest securing such notes to the security
                  interest of the Collateral Agent, in each case pursuant to
                  subordination and intercreditor provisions reasonably
                  acceptable to the Administrative Agent.

                  "New Lender Supplement": the agreement made pursuant to
                  Section 2.7 substantially in the form of Exhibit J.

                  "Non-Core Assets": at any time of determination (i) all
                  international licenses held by the Borrower or any of its
                  Subsidiaries in markets where full-scale commercial service
                  has not been launched at such time and (ii) all international
                  joint ventures and international Subsidiaries, which, in the
                  case of clauses (i) and (ii) above, are not material to the
                  business, property or condition (financial or otherwise) of
                  the Borrower and its Subsidiaries taken as a whole.

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                  "Operating Accounts": as defined in Section 6.13.

                  "Optional Non-Vendor Loan Commitment": as to any Lender, the
                  obligation of such Lender, if any, to make an Optional
                  Non-Vendor Loan to the Borrower hereunder in a principal
                  amount not to exceed the amount set forth in the Optional Term
                  Loan Amendment related thereto.

                  "Optional Non-Vendor Loan":  as defined in Section 2.7.

                  "Optional Non-Vendor Loan Lender":  each Lender which has an
                  Optional Non-Vendor Commitment or which is the holder of an
                  Optional Non-Vendor Loan.

                  "Optional Non-Vendor Loan Tranche":  as defined in Section
                  2.7.

                  "Optional Vendor Commitment": as to any Optional Vendor Loan
                  Lender, the obligation of such Optional Vendor Loan Lender, if
                  any, to make an Optional Vendor Loan to the Borrower hereunder
                  in a principal amount not to exceed the amount set forth in
                  the Optional Term Loan Amendment related thereto.

                  "Optional Vendor Loan":  as defined in Section 2.7.

                  "Optional Vendor Loan Lender":  each Lender which has an
                  Optional Vendor Commitment or which is the holder of an
                  Optional Vendor Loan.

                  "Optional Vendor Loan Tranche":  as defined in Section 2.7.

                  "Vendor":  a vendor of plant, property, services or equipment
                  and/or similar or related Property to the Borrower or its
                  Subsidiaries, the sale or other provision of which is
                  financed, in whole or in part, pursuant to Optional Vendor
                  Loans.

                  (c) Section 1.1 is hereby further amended by deleting the
definition of "Unused Proceeds Basket".

                  3.    Amendment to Section 2.7.  Section 2.7 is hereby
amended so that it shall read in its entirety as follows:

                  (a) Optional Non-Vendor Loans. Subject to the terms and
                  conditions hereof, the Borrower may, with the consent of the
                  Required Lenders, at any time and from time to time prior to
                  December 31, 2001, establish one or more additional non-vendor
                  term loan tranches (each, an "Optional Non-Vendor Loan
                  Tranche") pursuant to which non-vendor term loans ("Optional
                  Non-Vendor Loans") may be made, provided, (i) each Optional
                  Non-Vendor Loan Tranche shall be in a principal amount of at
                  least $50,000,000 and (ii) all Optional Non-Vendor Loan
                  Tranches shall not exceed in the aggregate the difference of
                  (A) $600,000,000 less (B) the aggregate amount of Optional
                  Vendor Loan Tranches then in effect. The Borrower may offer to
                  any existing Lender, or to one or more additional banks,
                  financial institutions or other entities reasonably acceptable
                  to the Administrative Agent, the opportunity to participate in
                  all or a portion of an Optional Non-Vendor Loan Tranche.

                  (b) Optional Vendor Loans. Subject to the terms and conditions
                  hereof, the

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                  Borrower may at any time and from time to time prior to
                  December 31, 2001, establish one or more vendor loan tranches
                  (each, an "Optional Vendor Loan Tranche") pursuant to which
                  vendor loans ("Optional Vendor Loans") may be made by one or
                  more Vendors, provided, (i) each Optional Vendor Loan Tranche
                  shall be in a principal amount of at least $50,000,000 and
                  (ii) all Optional Vendor Loan Tranches shall not exceed
                  $350,000,000 in the aggregate or, if less, the difference of
                  (A) $600,000,000 less (B) the aggregate amount of Optional
                  Non-Vendor Loan Tranches then in effect. The Borrower may
                  offer to any existing Optional Vendor Loan Lender, or to one
                  or more additional Vendors reasonably acceptable to the
                  Administrative Agent, the opportunity to participate in all or
                  a portion of an Optional Vendor Loan Tranche. Proceeds of
                  Optional Vendor Loans may be used only to finance Capital
                  Expenditures and services related to Capital Expenditures.

                  (c) Optional Term Loan Procedures. The Borrower shall request
                  the establishment of an Optional Term Loan Tranche by delivery
                  to the Administrative Agent of a written request therefor (an
                  "Optional Term Loan Request") which shall be promptly
                  distributed by the Administrative Agent to the applicable
                  Lenders. Each Optional Term Loan Request shall (i) set forth
                  the aggregate principal amount of the requested Optional Term
                  Loan Tranche and the Applicable Margin (or, if applicable, the
                  formula for the calculation thereof) and the commitment fee
                  rate, if any, applicable to the Optional Term Loans to be made
                  under such Optional Term Loan Tranche, the amortization and
                  maturity date of such Optional Term Loans and the borrowing
                  procedures relating to the borrowing by the Borrower of such
                  Optional Term Loans and (ii) if applicable, be accompanied by
                  such information as the Administrative Agent shall reasonably
                  request for use in syndication of the requested Optional Term
                  Loans. All Optional Term Loans shall (I) have a Weighted
                  Average Life (calculated on the date the related Optional Term
                  Loan Tranche shall become effective) that is at least as long
                  as the then Weighted Average Life (calculated on such date) of
                  the Revolving Credit Commitments and the Term Loans, taken as
                  a whole, (II) have a final scheduled maturity date on or after
                  December 31, 2006, (III) bear interest at rates no higher than
                  those applicable to the Tranche A Term Loans, (IV) otherwise
                  be subject to the same terms and conditions as the other Term
                  Loans outstanding hereunder, (V) be subject to no other
                  conditions other than, in the case of Optional Vendor Loans,
                  the requirement that the proceeds be used to purchase
                  equipment and/or services from or through the applicable
                  Vendors and (VI) be in form and substance otherwise reasonably
                  satisfactory to the Administrative Agent. No Lender shall have
                  any obligation to participate in any Optional Term Loan
                  Tranche unless it agrees to do so in its sole discretion. All
                  Optional Term Loan Tranches shall not exceed $600,000,000 in
                  the aggregate.

                  (d) New Lenders. In the case of any Optional Non-Vendor Loan
                  Tranche, any banks, financial institutions or other entities,
                  and, in the case of any Optional Vendor Loan Tranche, any
                  Vendor, which elects to become a party to this Agreement and
                  obtain an Optional Term Loan Commitment pursuant to this
                  Section 2.7 shall execute a New Lender Supplement (each, a
                  "New Lender Supplement") with the Borrower and the
                  Administrative Agent, substantially in the form of Exhibit J,
                  whereupon such lender (herein called a "New Lender")

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                  shall become an Optional Term Loan Lender for all purposes and
                  to the same extent as if originally a party hereto and shall
                  be bound by and entitled to the benefits of this Agreement and
                  the other Loan Documents, and Schedule 1.1 shall be deemed to
                  be amended to add the name and Optional Non-Vendor Loan
                  Commitment or Optional Vendor Commitment, as applicable, of
                  such New Lender.

                  (e) Conditions to Effectiveness. The effectiveness of any
                  Optional Term Loan Tranche shall be contingent upon (i)
                  execution and delivery by the Administrative Agent, the
                  Borrower and each Lender providing Optional Term Loan
                  Commitments under such Optional Term Loan Tranche of an
                  Optional Term Loan Amendment relating to such Optional Term
                  Loan Tranche, (ii) receipt by the Administrative Agent of such
                  corporate resolutions and officer's certificates of the
                  Borrower and legal opinions of counsel to the Borrower as the
                  Administrative Agent shall reasonably request with respect
                  thereto, and (iii), if applicable, execution and delivery by
                  the Borrower, the Administrative Agent and each New Lender
                  providing Optional Term Loan Commitments under such Optional
                  Term Loan Tranche of the New Lender Supplement, in each case
                  in form and substance reasonably satisfactory to the
                  Administrative Agent. The Borrower and the Administrative
                  Agent agree to negotiate in good faith any Optional Term Loan
                  Amendment relating to any Optional Term Loan Tranche.

                  4.    Amendment to Section 2.12.  Section 2.12 is hereby
amended so that it shall read in its entirety as follows:

                  Optional Prepayments. The Borrower may at any time and from
                  time to time prepay the Term Loans and reduce the Revolving
                  Credit Commitments, in whole or in part, without premium or
                  penalty except as provided in the last sentence of this
                  Section, upon irrevocable notice delivered to the
                  Administrative Agent at least three Business Days prior
                  thereto in the case of Eurodollar Loans and at least one
                  Business Day prior thereto in the case of ABR Loans, which
                  notice shall specify the date and amount of prepayment and
                  whether the prepayment is of Eurodollar Loans or ABR Loans;
                  provided, that if a Eurodollar Loan is prepaid on any day
                  other than the last day of the Interest Period applicable
                  thereto, the Borrower shall also pay any amounts owing
                  pursuant to Section 2.22; provided, further, that any
                  prepayment made pursuant to this Section 2.12 shall be applied
                  pro rata to (i) the Tranche A Term Loans, (ii) the Conversion
                  Term Loans, (iii) the Optional Term Loans, (iv) the reduction
                  of the Delayed Draw Term Loans and (v) the reduction of the
                  Revolving Credit Commitments. Upon receipt of any such notice
                  the Administrative Agent shall promptly notify each relevant
                  Lender thereof. If any such notice is given, the amount
                  specified in such notice shall be due and payable on the date
                  specified therein, together with accrued interest to such date
                  on the amount prepaid. Any reduction of the Revolving Credit
                  Commitments pursuant to this Section 2.12 shall be accompanied
                  by prepayment of the Revolving Credit Loans to the extent, if
                  any, that the aggregate outstanding principal amount of
                  Revolving Credit Loans exceeds the amount of the Total
                  Revolving Credit Commitments as so reduced. Partial
                  prepayments of Term Loans and Revolving Credit Commitments
                  shall be in an aggregate principal amount of $1,000,000 or a
                  whole multiple thereof. Optional prepayments of the

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                  Term Loans occurring prior to the first anniversary of the
                  Closing Date shall be accompanied by a prepayment fee equal to
                  3% of the amount of such prepayment.

                  5.    Amendment to Section 2.13.  (a)  Section 2.13(b) is
hereby amended so that it shall read in its entirety as follows:

                  (b) Unless the Required Prepayment Lenders shall otherwise
                  agree, if on any date the Borrower or any of its Subsidiaries
                  shall receive Net Cash Proceeds from any Asset Sale or
                  Recovery Event by the Borrower or its Subsidiaries then,
                  unless a Reinvestment Notice shall be delivered in respect
                  thereof within five Business Days after receipt of such Net
                  Cash Proceeds, such Net Cash Proceeds shall be applied on such
                  date toward the prepayment of the Term Loans and the reduction
                  of the Revolving Credit Commitments as set forth in Section
                  2.13(d); provided, that, on each Reinvestment Prepayment Date,
                  an amount equal to the Reinvestment Prepayment Amount with
                  respect to the relevant Reinvestment Event shall be applied
                  toward the prepayment of the Term Loans and the reduction of
                  the Revolving Credit Commitments as set forth in Section
                  2.13(d); and provided, further, that (i) the Borrower may not
                  at any time deliver a Reinvestment Notice with respect to more
                  than 35% of the Net Cash Proceeds of any Asset Sale and (ii)
                  any Net Cash Proceeds of Asset Sales in respect of which
                  Reinvestment Notices have been delivered shall be reinvested
                  in tangible Property, including the installation thereof and
                  services reasonably related to such installation, located in
                  the United States of America useful in the business of the
                  Borrower consistent with its past practice and with normal
                  industry practice in accordance with this Section 2.13. If at
                  any time the aggregate amount of Net Cash Proceeds of Asset
                  Sales in respect of which Reinvestment Notices have been
                  delivered shall exceed 35% of the aggregate amount of Net Cash
                  Proceeds theretofore received from Asset Sales, then the
                  Borrower promptly shall apply such excess over 35% in
                  accordance with Section 2.13(d). In addition, if at any time
                  the aggregate amount of Net Cash Proceeds in respect of which
                  Reinvestment Notices have been delivered and which have not
                  been reinvested in accordance with such Reinvestment Notices
                  or applied in accordance with Section 2.13(d) shall exceed
                  $5,000,000, then the Borrower promptly shall deliver such
                  excess over $5,000,000 to the Collateral Agent to be held by
                  it in accordance with the Collateral Agency and Intercreditor
                  Agreement.

                  (b) Section 2.13(d) is hereby amended so that it shall read in
its entirety as follows:

                  (d) Amounts to be applied in connection with prepayments and
                  Commitment reductions made pursuant to Section 2.13(a), (b) or
                  (c) or Section 6.6 shall be applied to the prepayment of the
                  Term Loans, the reduction of the Revolving Credit Commitments
                  and the reduction of any Delayed Draw Term Loan Commitments
                  then unused and in effect, pro rata according to the
                  respective amounts of the outstanding Term Loans, outstanding
                  Revolving Credit Commitments and unused Delayed Draw Term Loan
                  Commitments then in effect. Any such reduction of the
                  Revolving Credit Commitments shall be accompanied by
                  prepayment of the Revolving Credit Loans to the extent, if
                  any, that the aggregate outstanding principal amount of
                  Revolving Credit Loans exceeds the amount of the Total
                  Revolving Credit Commitments as so reduced. The

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                  application of any prepayment pursuant to this Section shall
                  be made first to ABR Loans and second to Eurodollar Loans.
                  Each prepayment of the Loans under this Section (except in the
                  case of Revolving Credit Loans that are ABR Loans) shall be
                  accompanied by accrued interest to the date of such prepayment
                  on the amount prepaid. No prepayment fee shall be payable in
                  connection with any prepayment or Commitment reduction
                  required by paragraphs (a) through (c) above.

                  (c) Section 2.13(e) is hereby amended so that it shall read in
its entirety as follows:

                  (e)  [Reserved.]

                  6.    Amendment to Lead-In to Section 5.  The lead-in to
Section 5 is hereby amended so that it shall read in its entirety as follows:

                  The Borrower hereby agrees that, so long as any Commitment
                  remains in effect or any Loan or other amount is owing to any
                  Lender or any Agent hereunder, the Borrower shall and, except
                  in the case of delivery of financial statements and
                  information, reports and notices and except in the case of
                  agreements pursuant to Section 5.12 and 5.13 hereof, shall
                  cause each of its Restricted Subsidiaries to:

                  7.    Waiver to Section 5.1(a). The requirement of Section
5.1(a) of the Credit Agreement that the independent certified public
accountants' report which accompanies the audited financial statements shall not
contain a "`going concern' or like qualification or exception" shall be waived
for the fiscal year ended December 31, 2000 insofar as such "going concern"
qualification results from the Borrower having incurred recurring operating
losses and having a substantial need for working capital.

                  8.    Amendment to Section 5.2(d).  Section 5.2(d) is hereby
amended so that it shall read in its entirety as follows:

                  (d) concurrently with the delivery of any financial statements
                  pursuant to Section 5.1, a narrative discussion and analysis
                  of the financial condition and results of operations of the
                  Borrower and its Subsidiaries for such fiscal quarter and for
                  the period from the beginning of the then current fiscal year
                  to the end of such fiscal quarter, as compared to the portion
                  of the Projections covering such periods and to the comparable
                  periods of the previous year;

                  9.     Amendment to Section 5.10.  (a)  Section 5.10(a) is
hereby amended so that it shall read in its entirety as follows:

                  (a) Promptly (i) transfer to LicenseCo any FCC License held by
                  the Borrower or any Restricted Subsidiary and take any other
                  actions as shall be required to cause the Collateral Agent to
                  have a perfected first priority security interest therein (to
                  the extent permissible under applicable law), (ii) create on
                  terms reasonably acceptable to the Administrative Agent a
                  perfected first priority security interest in favor of the
                  Collateral Agent in all Personal Property Assets now owned or
                  hereafter acquired by the Borrower or any Restricted
                  Subsidiary (including any Personal Property Assets owned or
                  hereafter acquired by AssetCo) and any Personal Property
                  Assets of any Person that becomes a Restricted Subsidiary or
                  is

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                  merged with or into or consolidated with the Borrower or any
                  Restricted Subsidiary (in each case other than any such
                  Personal Property Assets constituting Excluded Assets) and
                  (iii) without limiting the requirements of Section 5.10(c), at
                  the option of the Borrower, either (x) transfer to LeasingCo
                  any Real Property Assets hereafter acquired by the Borrower or
                  any Restricted Subsidiary and any Real Property Assets of any
                  Person that becomes a Restricted Subsidiary or is merged with
                  or into or consolidated with the Borrower or any Restricted
                  Subsidiary (in each case other than any such Real Property
                  Assets constituting Excluded Assets) or (y) create on terms
                  reasonably acceptable to the Administrative Agent a perfected
                  first priority security interest in favor of the Collateral
                  Agent in such Real Property Assets, other than Excluded Assets
                  (which security interest may be subject to any Liens permitted
                  by Section 6.3 (other than those referred to in the definition
                  of the term "Excluded Assets") .

                  (b) Section 5.10(c) is hereby amended so that it shall read in
its entirety as follows:

                  (c) Promptly create a mortgage on terms reasonably acceptable
                  to the Administrative Agent in favor of the Collateral Agent
                  on any fee simple title in real property owned by the Borrower
                  or any Restricted Subsidiary having at the time of acquisition
                  thereof a purchase price or fair market value greater than
                  $1,000,000 (other than Excluded Assets), including any such
                  properties that are acquired by the Borrower or any Restricted
                  Subsidiary after the date hereof and any such properties of
                  any Person that becomes a Restricted Subsidiary or is merged
                  with or into or consolidated with the Borrower or any
                  Restricted Subsidiary.

                  (b) Section 5.10(d) is hereby amended so that it shall read in
its entirety as follows:

                  (d) Promptly cause (i) all Capital Stock of any Subsidiary
                  (including, without limitation, any Subsidiary which shall be
                  acquired by the Borrower or any Restricted Subsidiary) held by
                  the Borrower or its Restricted Subsidiaries to be pledged to
                  the Collateral Agent as Collateral; provided, that only 65% of
                  the Capital Stock of any Excluded Foreign Subsidiary which is
                  a Subsidiary of the Borrower or any Domestic Subsidiary, and
                  none of the Capital Stock of any Subsidiary of an Excluded
                  Foreign Subsidiary, shall be required to be pledged and (ii)
                  each Restricted Subsidiary to become a party to the Guarantee
                  and Collateral Agreement.

                  10.    Amendment to Section 5.  Section 5 is hereby amended to
add, after Section 5.11, the following new Sections 5.12 and 5.13 as follows:

                  5.12 Convertible Notes. Deliver to the Administrative Agent,
                  on or before April 30, 2001, definitive documentation, duly
                  authorized, executed and delivered by the Borrower and such
                  Person or Persons as determined by the Borrower with respect
                  to the Convertible Notes, on terms and conditions reasonably
                  satisfactory to the Administrative Agent and in an aggregate
                  principal amount equal to or in excess of $100,000,000.

                                       10
<PAGE>

                  5.13 Vendor Financing. Deliver to the Administrative Agent, on
                  or before April 30, 2001, definitive documentation, duly
                  authorized, executed and delivered by the Borrower and one or
                  more Vendors, including a New Lender Supplement duly executed
                  and delivered by the Borrower and each relevant Vendor, with
                  respect to the establishment of one or more Optional Vendor
                  Loan Tranches pursuant to Section 2.7 of, and in all material
                  respects in accordance with, this Agreement in an aggregate
                  principal amount equal to or in excess of $250,000,000.

                  11.    Amendment to Section 6.1.  (a)  Section 6.1(a) is
hereby amended so that it shall read in its entirety as follows:

                  (a) Consolidated Total Debt to Consolidated Adjusted
                  Capitalization. Permit the ratio of Consolidated Total Debt to
                  Consolidated Adjusted Capitalization during any test period
                  set forth below to be greater than the ratio set forth below
                  opposite such test period:

<TABLE>
<CAPTION>
                  Test Period                           Ratio
                  <S>                                   <C>
                  Closing Date - 12/31/98               60%
                  1/1/99 - thereafter                   65%
</TABLE>

                  (b) Section 6.1(b) is hereby amended so that it shall read in
its entirety as follows:

                  (b) Consolidated Secured Debt to Consolidated Adjusted
                  Capitalization. Permit the ratio of Consolidated Secured Debt
                  to Consolidated Adjusted Capitalization during any test period
                  set forth below to be greater than the ratio set forth below
                  opposite such test period:

<TABLE>
<CAPTION>
                  Test Period                           Ratio
                  <S>                                   <C>
                  Closing Date - 12/31/98               30%
                  1/1/99 -  thereafter                  40%
</TABLE>

                  (c) Section 6.1(c) is hereby amended so that it shall read in
its entirety as follows:

                  (c)  Minimum Consolidated Total Revenue.  Permit Consolidated
Total Revenue for any fiscal quarter set forth below to be less than the amount
set forth opposite such fiscal quarter below:

<TABLE>
<CAPTION>
                  Fiscal Quarter Ending                 Amount
                  <S>                                   <C>
                  3/31/01                               $55,000,000
                  6/30/01                               $68,000,000
</TABLE>

                  (d) Section 6.1(f) is hereby amended to delete the last
sentence thereof, which read, "In addition to the amounts set forth above,
Capital Expenditures may be funded from the Unused Proceeds Basket".

                  (e) Section 6.1(j) is hereby amended so that it shall read in
its entirety as follows:

                                       11
<PAGE>

                  (j) Consolidated Fixed Charge Coverage Ratio. (a)(i) From the
                  fiscal quarter ending June 30, 2001 through the fiscal quarter
                  ending September 30, 2003, permit the Consolidated Fixed
                  Charge Coverage Ratio on the last day of any fiscal quarter
                  ending on any date set forth below to be less than the ratio
                  set forth opposite such date below:

<TABLE>
<CAPTION>
                           Fiscal Quarter Ending        Ratio
                           <S>                          <C>

                           6/30/01                      2.00

                           9/30/01                      1.75

                           12/31/01                     2.50

                           3/31/02 through 9/30/03      1.25; and
</TABLE>

                  (ii) From the fiscal quarter ending December 31, 2003 and
                  thereafter, permit the Consolidated Fixed Charge Coverage
                  Ratio for any period of four consecutive fiscal quarters
                  ending during any test period set forth below to be less than
                  the ratio set forth opposite such test period below:

<TABLE>
                           <S>                          <C>
                           12/31/03 through 9/30/04     1.10

                           12/31/04 and thereafter      1.25; or
</TABLE>

                  (b) From the fiscal quarter ending June 30, 2001 through the
                  fiscal quarter ending September 30, 2003, fail to deliver to
                  the Administrative Agent and the Lenders, on or before the
                  date which is ten Business Days after the end of any fiscal
                  quarter, a certificate of a Responsible Officer showing
                  calculations demonstrating compliance with the foregoing
                  clause (i) on the last day of such fiscal quarter.

                  (f) Section 6.1 is hereby amended to add the following new
Section 6.1(k) below:

                  (k) Minimum Consolidated EBITDA. Permit Consolidated EBITDA
                  for the period ending on the last day of the fiscal quarter
                  set forth below to be less than the amount set forth opposite
                  such fiscal quarter below:

<TABLE>
<CAPTION>
                  Fiscal Quarter Ending                 Amount
                  <S>                                   <C>
                         3/31/01                        (96,900,000)
                         6/30/01                        (76,300,000)
                         9/30/01                        (49,200,000)
                         12/31/01                       (30,400,000)
                         3/31/02                        (19,400,000)
                         6/30/02                        (10,900,000)
                         9/30/02                          1,800,000
                         12/31/02                        23,300,000
                         3/31/03                         42,200,000
                         6/30/03                         59,500,000
                         9/30/03                         84,300,000
                         12/31/03                        99,900,000

                                       12
<PAGE>

                         3/31/04                        114,900,000
                         6/30/04                        133,600,000
                         9/30/04                        156,300,000
                         12/31/04                       173,900,000
</TABLE>

                  (g) Section 6.1 is hereby amended to add the following new
Section 6.1(l) below:

                  (l) Minimum Liquidity. Permit the aggregate amount of cash and
                  Cash Equivalents held in (i) the Operating Accounts of the
                  Borrower and (ii) the Collateral and Securities Account of the
                  Borrower held at The Chase Manhattan Bank, in each case
                  pursuant to Section 6.13 of this Agreement, to be less than
                  $150,000,000 on March 31, 2001.

                  12.    Waiver of Section 6.1(j). The parties hereto hereby
agree that the requirement of Section 6.1(j) that the Consolidated Fixed Charge
Coverage Ratio on the last day of the fiscal quarter ending December 31, 2000 be
equal to or more than 1.10 shall be waived.

                  13.    Amendment to Section 6.2.  (a)  Section 6.2(c) is
hereby amended so that it shall read in its entirety as follows:

                  (c) Indebtedness (including, without limitation, Capital Lease
                  Obligations) secured by Liens permitted by Section 6.3(g);
                  provided, that (i) not more than $25,000,000 of such
                  Indebtedness may be incurred to finance the acquisition of
                  Network Assets (other than fiber or fiber capacity) and (ii)
                  that not more than $100,000,000 of such Indebtedness may be
                  incurred to finance the acquisition of fiber or fiber
                  capacity;

                  (b) Section 6.2 is hereby further amended by (i) deleting the
word "and" at the end of clause (j), (ii) deleting the period at the end of
clause (k) and inserting a semi-colon and the word "and" in lieu thereof and
(iii) adding the following new clause (l):

                  (l) Indebtedness incurred under the Convertible Notes in an
                  aggregate principal amount not to exceed $150,000,000.

                  14.    Consent to Section 6.2(g). The parties hereto hereby
agree that the requirement of Section 6.2(g)(x) that unsecured Indebtedness or
preferred stock of the Borrower issued or incurred after July 2, 1998 generating
the first $500,000,000 in Net Cash Proceeds shall provide for interest or
dividends thereon to be paid in kind (or to be paid out of amounts deposited in
escrow or pledged as collateral from the proceeds thereof) for at least three
years after the date of incurrence or issuance thereof shall be deemed
satisfied.

                  15.    Amendment to Section 6.3.  (a) Section 6.3(g) is hereby
amended to read in its entirety as follows:

                  (g) Liens securing Indebtedness of the Borrower or any
                  Restricted Subsidiary incurred pursuant to Section 6.2(c) to
                  finance the acquisition or capital lease of fixed or capital
                  assets, provided that (i) such Liens shall be created within
                  90 days from the acquisition of such fixed or capital assets
                  and (ii) such Liens do not at any time encumber any Property
                  other than the Property financed by such Indebtedness;

                                       13
<PAGE>

                  (b) Section 6.3 is hereby further amended by (i) deleting the
word "and" at the end of clause (k), (ii) deleting the period at the end of
clause (l) and inserting a semi-colon in lieu thereof and (iii) adding the
following new clauses (m), (n) and (o):

                  (m) Uniform Commercial Code filings with respect to operating
                  leases or consignment arrangements entered into in the
                  ordinary course of business of the Borrower or any of its
                  Restricted Subsidiaries, to the extent filed to reflect the
                  interests of the lessor or relevant party in respect of such
                  leases or consignment arrangements, as the case may be;

                  (n) Liens in favor of banking institutions arising by
                  operation of law encumbering deposits held by such banking
                  institution incurred by the Borrower or its Restricted
                  Subsidiaries in the ordinary course of business; and

                  (o) second priority Liens on the Collateral securing the
                  obligations under the Convertible Notes permitted pursuant to
                  Section 6.2(l), provided, that (i) such Liens shall be subject
                  to customary second lien and Indebtedness subordination
                  provisions satisfactory to the Administrative Agent providing,
                  among other things, that such Liens shall be subject to the
                  priority of Liens securing the Obligations (including with
                  respect to the exercise of remedies and decisions relating to
                  the Collateral) and that the obligations under the Convertible
                  Notes shall be subordinated to the Obligations and (ii) the
                  documentation with respect to such Liens shall include an
                  intercreditor agreement and such other documentation
                  reasonably requested by the Administrative Agent, satisfactory
                  in form and substance to the Administrative Agent.

                  16.    Amendment to Section 6.5.  (a)  Sections 6.5(c) is
hereby amended so as to read in its entirety as follows:

                  (c) so long as after giving effect thereto the Borrower is in
                  Pro Forma Compliance, any Asset Sale for fair market value;
                  provided, that (i) the aggregate consideration in connection
                  with all Asset Sales shall not exceed $200,000,000 and (ii)
                  the Net Cash Proceeds of all Asset Sales shall be applied in
                  accordance with Section 2.13;

                  (b) The proviso at the end of Sections 6.5 is hereby amended
so as to read in its entirety as follows:

                  provided that in each case described in clauses (c) and (e)
                  above, at least 75% of the consideration received by the
                  Borrower or its Restricted Subsidiaries for such Disposition
                  shall consist of cash and Cash Equivalents.

                  17.    Amendment to Section 6.7.  (a)  Sections 6.7(d), (e)
and (f) are hereby amended so as to read in their entirety as follows:

                  (d) Investments by the Borrower and its Restricted
                  Subsidiaries (other than the Special Purpose Subsidiaries) in
                  Unrestricted Subsidiaries and joint ventures, provided, that
                  (x) the consideration for such Investments made after the
                  Effective Date in excess of $25,000,000 in the aggregate shall
                  be the common stock of the Borrower, (y) the consideration for
                  such Investments made after the Effective

                                       14
<PAGE>

                  Date may not include, directly or indirectly, the Disposition
                  of any Network Assets of the Borrower or any Restricted
                  Subsidiary (including, without limitation, licenses, whether
                  domestic or foreign, but excluding, the entering into of one
                  or more management agreements with respect to spectrum by any
                  Restricted Subsidiary to any Unrestricted Subsidiary or other
                  Person; provided, that such agreements are (A) compliant with
                  all material terms of this Agreement as determined by the
                  Administrative Agent in good faith (including, without
                  limitation, that all Net Cash Proceeds of such management
                  agreement shall be applied in accordance with Section 2.13)
                  and (B) reasonably satisfactory in form and substance to FCC
                  counsel to the Lenders), and (z) after giving effect to such
                  Investment the Borrower shall be in Pro Forma Compliance;

                  (e) Investments in wireless telecommunications licenses issued
                  by a governmental authority, including FCC Licenses, and in
                  Persons engaged in the telecommunications business and
                  substantially all of whose assets consist of wireless
                  telecommunications licenses which become Restricted
                  Subsidiaries as a result of such Investment, provided, that
                  (w) the consideration for such Investments shall be the common
                  stock of the Borrower, (x) with respect to Investments in
                  Persons pursuant to this clause (e), such Investments shall be
                  made only in Persons which have provided to the Administrative
                  Agent financial statements certified by the chief financial
                  officer of such Person reflecting a positive EBITDA for such
                  Person for the immediately preceding consecutive twelve-month
                  period, (y) after giving effect to such Investment the
                  Borrower shall be in Pro Forma Compliance and (z) the
                  consideration for Investments made in telecommunications
                  licenses issued by any Governmental Authority outside the
                  United States shall be the common stock of the Borrower;

                  (f) Investments in additional Telecommunications Assets,
                  excluding wireless telecommunications licenses, and in Persons
                  engaged in the telecommunications business which become
                  Restricted Subsidiaries as a result of such Investment,
                  provided, that (x) the consideration for such Investments
                  shall be the common stock of the Borrower, (y) with respect to
                  Investments in Persons pursuant to this clause (f), such
                  Investments shall be made only in Persons which have provided
                  to the Administrative Agent financial statements certified by
                  the chief financial officer of such Person reflecting a
                  positive EBITDA for such Person for the immediately preceding
                  consecutive twelve-month period, and (z) after giving effect
                  to each such Investment the Borrower shall be in Pro Forma
                  Compliance;

                  18.    Amendment to Section 6.12(b).  Sections 6.12(b) is
hereby amended so as to read in its entirety as follows:

                  (b) Permit LicenseCo to incur any material liabilities (other
                  than pursuant to the Loan Documents) or to engage in any
                  business or activities other than (i) the holding of Licenses,
                  (ii) the entering into of one or more management agreements
                  with respect to spectrum with any Unrestricted Subsidiary or
                  other Person (provided, that such agreements are (A) compliant
                  with all material terms of this Agreement as determined by the
                  Administrative Agent in good faith (including, without
                  limitation, that all Net Cash Proceeds of such management
                  agreement shall be applied in accordance with Section 2.13)
                  and (B) reasonably satisfactory

                                       15
<PAGE>

                  in form and substance to FCC counsel to the Lenders) and (iii)
                  in each case, to engage in activities directly incident or
                  directly related thereto.

                  19.    Addition of Section 6.13.  The following shall be added
as Section 6.13:

                  6.13.  Maintenance of Cash and Cash Equivalents.  From and
                  after the Amendment Effective Date, hold, directly indirectly,
                  any cash or Cash Equivalents, except as follows:

                           (a) the Borrower and its Restricted Subsidiaries may
                  hold cash in operating accounts maintained with any bank or
                  other financial institution reasonably satisfactory to the
                  Administrative Agent (the "Operating Accounts") so long as, at
                  the close of business on any day (after giving effect to any
                  transfers at such close of business to the Collateral and
                  Securities Account), the amount on deposit in all Operating
                  Accounts shall not exceed, in the aggregate, $25,000,000; and

                           (b) the Borrower and its Restricted Subsidiaries
                  shall maintain all cash and Cash Equivalents, other than cash
                  on deposit in an Operating Account to the extent permitted by
                  the foregoing paragraph (a), in an account or accounts
                  (collectively, the "Collateral and Securities Account") at The
                  Chase Manhattan Bank, which shall be established and
                  maintained upon the following terms:

                                    (i) the Collateral and Securities Account
                           shall be established pursuant to agreements in form
                           and substance reasonably satisfactory to the
                           Administrative Agent, which shall in any event
                           provide that (1) the Collateral and Securities
                           Account, and all cash and Cash Equivalents from time
                           to time credited thereto, and all earnings thereon,
                           shall constitute Collateral in which the Collateral
                           Agent has a security interest to secure the Secured
                           Obligations (as defined in the Collateral Agency and
                           Intercreditor Agreement) and (2) the Collateral Agent
                           shall have sole dominion and control of the
                           Collateral and Securities Account, and neither the
                           Borrower nor any Restricted Subsidiary shall have any
                           right of withdrawal therefrom, except as provided in
                           clause (ii) below;

                                    (ii) upon receipt by the Collateral Agent of
                           a request from the Borrower (1) stating that the
                           aggregate amount on deposit in all Operating Accounts
                           as of the close of business on the immediately
                           preceding Business Day was not more than $25,000,000
                           and (2) requesting that the Collateral Agent transfer
                           from the Collateral and Securities Account to an
                           Operating Account funds in an amount which, after
                           giving effect to such transfer, will not cause the
                           provisions of this Section 6.13 to be violated, the
                           Collateral Agent will transfer such requested amount
                           in accordance with such request.

                  20.    Amendment to Section 7(c).  Section 7(c) is hereby
amended to read in its entirety as follows:

                  (c) The Borrower shall default in the observance or
                  performance of any agreement contained in Section 5.12 or
                  Section 5.13 or any Loan Party shall

                                       16
<PAGE>

                  default in the observance or performance of any agreement
                  contained in Section 6;

                  21.    Amendment to Section 9.5.  Section 9.5 of the Credit
Agreement is hereby amended by deleting clause (a) in its entirety and
substituting the following in lieu thereof:

                  (a) to pay or reimburse the Agents, and the formal and
                  informal members of any steering committee of Lenders, for all
                  their reasonable out-of-pocket costs and expenses incurred in
                  connection with the development, preparation and execution of,
                  and any amendment, supplement or modification to, this
                  Agreement and the other Loan Documents and any other documents
                  prepared in connection herewith or therewith, and the
                  consummation and administration of the transactions
                  contemplated hereby and thereby, including, without
                  limitation, the reasonable fees and disbursements of one
                  counsel for all of the Agents and any other consultants or
                  professional advisors (including, without limitation,
                  financial advisors) retained by the Administrative Agent,

                  22.    Amendment to Annex A.  Annex A to the Credit Agreement
is hereby deleted in its entirety.

                  23.    Amendment to Exhibits.  Exhibit J attached hereto as
Annex A shall hereby be added as Exhibit J to the Credit Agreement.


                  24.    Amendment to Section 3.2 of the Guarantee and
Collateral Agreement.  Section 3.2 is hereby amended to read in its entirety as
follows:

                  3.2 Limitation on Obligation to Perfect. Notwithstanding the
                  foregoing, it is understood and agreed that no Grantor will be
                  required to take any action to perfect any security interest
                  created hereby other than (A) the filing of financing
                  statements under the Uniform Commercial Code in the states
                  (and, where applicable, counties, towns and parishes)
                  necessary or, in the reasonable judgment of the Administrative
                  Agent, desirable to create a perfected first priority security
                  interest in the Personal Property Assets of such Grantor, (B)
                  the filings required in the United States Patent and Trademark
                  Office to perfect the security interest created hereby in any
                  material United States Patents or U.S. Trademarks owned or
                  held by such Grantor, (C) the filings and registrations
                  required in the United States Copyright Office to perfect the
                  security interest created hereby in any material United States
                  Copyrights owned or held by such Grantor, (D) delivery to the
                  Collateral Agent of any Possessory Collateral owned by such
                  Grantor and (E) any actions required to perfect the security
                  interest created hereby in any Non-Excluded Personal Property
                  which, in the case of any Real Property Assets, has not been
                  transferred to a LeasingCo; provided, that if after the date
                  hereof there is any change in law which requires actions in
                  addition to those described above to cause the security
                  interests created hereby to be perfected to the same extent as
                  the perfection effected by the foregoing actions under laws in
                  effect on the date hereof, the Grantors will take such
                  additional actions.

                  25.    Amendment to Section 5.3(a) of the Guarantee and
Collateral Agreement.  Section 5.3(a) is hereby amended by deleting the
reference to "Section 4.5" and substituting in lieu thereof a reference to
"Section 4.3".

                                       17
<PAGE>

                  26.    Amendment to Section 5.6(b)(ii) of the Guarantee and
Collateral Agreement.  Section 5.6(b)(ii) is hereby amended by inserting the
following phrase immediately after the word "instruments" and immediately before
the symbol ")":

                  , and any such Pledged Securities so sold, assigned,
                  transferred, exchanged or otherwise disposed of as permitted
                  by the Secured Instruments shall cease to be Pledged
                  Securities hereunder

                  27.    Conditions Precedent.  Subject to the satisfaction of
the following conditions, this Amendment will become effective as of March 30,
2001 (the "Effective Date"):

                  (a) Amendment. The Administrative Agent shall have received
         counterparts of this Amendment, duly executed by the Borrower, the
         Administrative Agent and the Required Lenders.

                  (b)  No Default or Event of Default.  On and as of the
         Effective Date after giving effect to this Amendment, no Default or
         Event of Default shall have occurred and be continuing.

                  (c) Representations and Warranties. The representations and
         warranties made by the Borrower in the Credit Agreement and the other
         Loan Documents after giving effect to this Amendment and the
         transactions contemplated hereby shall be true and correct in all
         material respects on and as of the Effective Date as if made on such
         date, except that where such representations and warranties relate to
         an earlier date, such representations and warranties shall have been
         true and correct in all material respects as of such earlier date,
         provided that all references to the Credit Agreement in such
         representations and warranties shall be and are deemed to mean this
         Amendment as well as the Credit Agreement as amended hereby.

                  (d) Certificate. The Administrative Agent shall have received
         a Certificate of a Responsible Officer of the Borrower certifying the
         matters referred to in paragraphs (b) and (c).

                  (e) Secretary's Certificate. The Administrative Agent shall
         have received a certificate from the Secretary or Assistant Secretary
         of the Borrower dated as of the Effective Date, (i) certifying attached
         copies of resolutions of the Board of Directors of the Borrower,
         authorizing the execution, delivery and performance of this Amendment,
         including the increase in the amount of the Optional Term Loan
         Commitments, contemplated hereby, (ii) certifying that the By-Laws and
         the Certificate of Incorporation of the Borrower have not been amended,
         restated, supplemented or otherwise modified since July 2, 1998, except
         for the amendments, restatements, supplements or modifications attached
         as an exhibit to such certificate, and (iii) evidencing the incumbency
         and signatures of the officers signing this Amendment.

                  (f) Opinions. The Administrative Agent shall have received in
         connection with this Amendment (i) an opinion of in-house counsel to
         the Borrower, covering such matters that the Administrative Agent shall
         reasonably request and customary for transactions of this type, and
         (ii) an enforceability opinion of Cravath, Swaine & Moore, special New
         York counsel to the Borrower, which opinion shall also cover the
         creation and perfection of the security interest of the Collateral
         Agent in the Collateral and

                                       18
<PAGE>

         Securities Account and the enforceability of the agreements entered
         into in connection therewith.

                  (g) Approvals. The Administrative Agent shall have received
         copies of all necessary corporate and governmental approvals (if any)
         of the Borrower for the increase of the aggregate amount of the
         Optional Term Loan Tranches, the addition of the Optional Vendor Loan
         Tranches therein, and any other transactions contemplated hereby.

                  (h) Fees and Expenses. The Administrative Agent shall have
         received all fees required to be paid, including, without limitation,
         an amendment fee for the account of each Lender which executes and
         delivers this Amendment on or before the date hereof of 25 basis points
         on such Lender's Commitment, and all expenses for which invoices have
         been presented, including, without limitation, all expenses required to
         be paid pursuant to Section 9.5 (after giving effect to this
         Amendment), on or before the date hereof.

                  (i) Subsidiary and Collateral Schedule. The Administrative
         Agent shall have received in connection with this Amendment a schedule
         or schedules listing (i) each direct and indirect Subsidiary of the
         Borrower, (ii) the Borrower's and each such Subsidiary's jurisdiction
         of incorporation, (iii) the location of the chief executive office of
         the Borrower and each Domestic Subsidiary, (iv) the locations of any
         tangible personal property of the Borrower and each Domestic
         Subsidiary, (v) the identity of the owner of the Capital Stock of each
         direct and indirect Subsidiary of the Borrower (and specifying whether
         such Capital Stock is certificated or uncertificated and, with respect
         to each Domestic Subsidiary and each Excluded Foreign Subsidiary which
         is a Subsidiary of the Borrower or any Domestic Subsidiary, if
         certificated, the share certificate number and the number of shares
         issued and outstanding) and (vi) each filing office in which UCC
         financing statements should be filed to perfect the security interest
         of the Collateral Agent in all personal property of the Borrower and
         each Restricted Subsidiary. Such schedules shall be accompanied by a
         certificate of the Borrower certifying such schedules to be true and
         correct.

                  28.    Continuing Effect; No Other Amendments. Except as
expressly amended or waived hereby, all of the terms and provisions of the
Credit Agreement and the other Loan Documents are and shall remain in full force
and effect. The amendments and consent contained herein shall not constitute an
amendment or consent of any other provision of the Credit Agreement or the other
Loan Documents or for any purpose except as expressly set forth herein.

                  29.    Binding Effect.  This Amendment shall apply equally to
each of the Lenders parties to the Credit Agreement, and shall be binding upon
the Borrower, the Lenders, the Administrative Agent, the Arrangers, the
Documentation Agent, the Syndication Agent and all future holders of the Notes.

                  30.    Governing Law.  THIS AMENDMENT AND THE RIGHTS AND
OBLIGATIONS OF THE PARTIES HEREUNDER SHALL BE CONSTRUED IN ACCORDANCE WITH AND
BE GOVERNED BY THE LAW OF THE STATE OF NEW YORK.

                  31.    Counterparts.  This Amendment may be executed in any
number of counterparts and by the different parties hereto in separate
counterparts, each of which when so executed and delivered shall be deemed to be
an original and all of which taken together shall

                                       19
<PAGE>

constitute one and the same instrument.  Delivery of an executed counterpart of
a signature page of this Amendment by facsimile transmission shall be as
effective as delivery of a manually executed counterpart of this Amendment.

                  32.    Headings.  Section headings in this Amendment are
included herein for convenience of reference only and shall not constitute a
part of this Amendment for any other purpose.

  [Remainder of this page left blank intentionally; Signature page to follow.]

                                       20
<PAGE>


                IN WITNESS WHEREOF, the parties hereto have caused this
Agreement to be executed by their duly authorized representatives as of the date
first above written.

                                                TELIGENT, INC.


                                                By:/s/ Alex J. Mandl
                                                   -----------------------
                                                Name:  Alex J. Mandl
                                                Title: Chief Executive Officer

                                                THE CHASE MANHATTAN BANK,
                                                As Administrative Agent


                                                By:/s/ William E. Rottino
                                                   -----------------------
                                                Name:  William E. Rottino
                                                Title:  Vice President

                                                [INSERT NAME OF LENDER],
                                                As a Lender


                                               By:_____________________________
                                               Name:
                                               Title:



                                       21

<PAGE>

                                                                         ANNEX A

                                                                       EXHIBIT J


                          FORM OF NEW LENDER SUPPLEMENT

                  SUPPLEMENT, dated _________________, to the Credit Agreement
dated as of July 2, 1998 (as amended, restated, supplemented or otherwise
modified from time to time, the "Credit Agreement"), among Teligent, Inc., a
Delaware corporation (the "Borrower"), the Lenders from time to time parties
thereto, Goldman Sachs Credit Partners L.P., as Syndication Agent, Toronto
Dominion (Texas), Inc., as Documentation Agent, and The Chase Manhattan Bank, as
Administrative Agent. Capitalized terms used herein without definition shall
have the meaning ascribed to such terms in the Credit Agreement.

                              W I T N E S S E T H :

                  WHEREAS, the Credit Agreement provides in Section 2.7 thereof
that, in the case of any Optional Non-Vendor Loan Tranche, any banks, financial
institutions or other entities, and, in the case of any Optional Vendor Loan
Tranche, any Vendor, to the Borrower may become a party to the Credit Agreement
as an Optional Term Loan Lender with the consent of the Borrower and the
Administrative Agent (which consent, in the case of the Administrative Agent,
shall not be unreasonably withheld) by executing and delivering to the Borrower
and the Administrative Agent a supplement to the Credit Agreement in
substantially the form of this Supplement; and

                  WHEREAS, the undersigned now desires to become a party to the
Credit Agreement;

                  NOW, THEREFORE, the undersigned hereby agrees as follows:

                  1. The undersigned agrees to be bound by the provisions of the
         Credit Agreement, and agrees that it shall, on the date this Supplement
         is accepted by the Borrower and the Administrative Agent, become an
         Optional [Non-]Vendor Loan Lender for all purposes of the Credit
         Agreement to the same extent as if originally a party thereto, with an
         Optional [Non-]Vendor Loan Commitment of [$____________].

                  2. The undersigned (a) represents and warrants that it is
         legally authorized to enter into this Supplement; (b) confirms that it
         has received a copy of the Credit Agreement, together with copies of
         the financial statements referred to in Section 5.1 thereof and such
         other documents and information as it has deemed appropriate to make
         its own credit analysis and decision to enter into this Supplement; (c)
         agrees that it has made and will, independently and without reliance
         upon any Agents or any other Lender and based on such documents and
         information as it shall deem appropriate at the time, continue to make
         its own credit decisions in taking or not taking action under the
         Credit Agreement or any instrument or document furnished pursuant
         hereto or thereto; (d) appoints and authorizes the Administrative Agent
         to take such action as agent on its behalf and to exercise such powers
         and discretion under the Credit Agreement or any instrument or document
         furnished pursuant hereto or thereto as are delegated to the

<PAGE>

         Administrative Agent by the terms thereof, together with such powers as
         are incidental thereto; and (e) agrees that it will be bound by the
         provisions of the Credit Agreement and will perform in accordance with
         its terms all the obligations which by the terms of the Credit
         Agreement are required to be performed by it as a Lender including,
         without limitation, if it is organized under the laws of a jurisdiction
         outside the United States, its obligation pursuant to Section 2.21 of
         the Credit Agreement.

                  3.  The undersigned's address for notices for the purposes of
         the Credit Agreement is as follows:



   [Remainder of the page left blank intentionally; Signature page to follow.]

                                       2
<PAGE>

                  IN WITNESS WHEREOF, the undersigned has caused this Supplement
to be executed and delivered by a duly authorized officer on the date first
above written.

                                                 [INSERT NAME OF LENDER]


                                                 By :_______________________
                                                     Name:
                                                     Title:

Accepted this _____ day of
________________, _______.


TELIGENT, INC.


By: ____________________________________
    Name:
    Title:




Accepted this ____ day of
________________, _______.

THE CHASE MANHATTAN BANK, as Administrative Agent


By: ___________________________
    Name:
    Title:


                                       3
<PAGE>


                                                                Exhibit A to the
                                                          Amendment and Consent,
                                                      dated as of March 30, 2001

                                Convertible Notes
                                   Term Sheet

Issuer:                    Teligent, Inc. (the "Company").

Investors:                 Such Persons as determined by the Company.

Issue:                     Convertible Notes, in one or more series (all series
                           taken together the "Notes").


Amount:                    Not to be less than $100 million nor to exceed $150
                           million.

Term:                      5.5 years from date of first draw down of the
                           respective Series.

Interest Rate:
(applicable to all series)

                           1.       From initial draw down to shareholder
                                    approval of the Exchange Rights and
                                    Warrants: Libor plus 550 basis points, cash
                                    pay, on drawn Notes.

                           2.       Upon shareholder approval of the Exchange
                                    Rights and the Warrants the rate is reset at
                                    8%, which, at the Company's option, shall be
                                    PIK or paid in the Company's common stock.

                           3.       If the Exchange Rights and the Warrants are
                                    not approved at the shareholder's meeting,
                                    then the Notes become due and payable six
                                    (6) months after such shareholders meeting.
                                    The Company will hold the shareholders
                                    meeting as soon as practicable, but in no
                                    case later than June 30, 2001.

Availability:              Each series  shall be  available  for draw down to
                           the Company in  tranches at any time after  closing.
                           All draws must be made within 15 months after the
                           execution of the definitive agreements for the Notes.

<PAGE>

Teligent, Inc. Convertible Notes Term Sheet                                   2

Conditions
Precedent:                 The  availability of one series,  which shall be in
                           an amount equal to or in excess of $25 million
                           ("Series A"), is contingent  only on: (a) the
                           Company's  obtaining a commitment(s)  for vendor
                           financing of at least $250 Million,  (b) the
                           Company's  closing on a commitment  for an additional
                           $50 million of debt or equity financing as permitted
                           by the Credit  Agreement  (as amended by the
                           Amendment),  which  condition  has been satisfied  by
                           the Common  Stock  Purchase  Agreement,  dated
                           December 7, 2000,  between  RGC  International
                           Investors,  LDC and the  Company,  and (c) the
                           Company's  granting  the Note  Holders a junior  lien
                           on the collateral pool pledged for the benefit of the
                           Company's lenders in the Credit Facility.

                           One series, which shall be in an amount equal to or
                           in excess of $75 million ("Series B"), shall close
                           after the end of Q2 2001, subject only to the
                           Company's meeting the Operating Milestones (described
                           below) for Q1 and Q2 2001. Following the closing of
                           Series B, draws against Series B shall coincide with
                           simultaneous draws against the vendor facility,
                           and/or other facilities available to the Company,
                           either debt or equity, in accordance with a ratio of
                           $1 dollar drawn against Series B for each $2 drawn
                           against other facilities.

Ranking:                   The Notes shall be subordinate, in right of payment,
                           to the Obligations, and any security interest
                           securing the Notes shall be subordinate to the
                           security interest of the Collateral Agent, in each
                           case pursuant to subordination and intercreditor
                           provisions reasonably acceptable to the
                           Administrative Agent.

Purpose:                   The Company may draw down on the Notes from time to
                           time only to finance the  acquisition and development
                           of telecommunications assets.

Exchange Rights:           Subject to shareholders  approval, the Note holders
                           may exchange the Notes for the Company's common stock
                           or into the common stock of Teligent  International,
                           Ltd. pursuant to terms agreed upon by the Company and
                           the Investors,   provided  that  the  amount
                           converted,   if  exchanged  into  the  common  stock
                           of  Teligent International,  Ltd.,  does not exceed
                           20% of the equity in  Teligent  International,  Ltd.
                           at the time of conversion.

Operating
Milestones:                There shall be no financial covenant requirements (i)
                           other than those set forth in Section 6.1 clauses (c)
                           and (k) of the Credit Agreement (as amended by the
                           Amendment) and (ii) for any period except Q1 and Q2
                           2001.