<PAGE>

                                                                    Exhibit 4.16


===============================================================================










                       CROWN CASTLE INTERNATIONAL CORP.


                                    ISSUER




                          9 3/8% SENIOR NOTES DUE 2011
                          ----------------------------

                                   INDENTURE

                           Dated as of May 16, 2001


                           ------------------------
                             The Bank of New York


                                    Trustee
                           ------------------------


================================================================================
<PAGE>

                            CROSS-REFERENCE TABLE*

<TABLE>
<CAPTION>
        Trust Indenture
           Act Section                                                                Indenture Section
        <S>                                                                           <C>
        310  (a)(1).............................................................             7.10
             (a)(2).............................................................             7.10
             (a)(3).............................................................             N.A.
             (a)(4).............................................................             N.A.
             (a)(5).............................................................             7.10
             (b)................................................................             7.10
             (c)................................................................             N.A.
        311  (a)................................................................             7.11
             (b)................................................................             7.11
             (c)................................................................             N.A.
        312  (a)................................................................             2.05
             (b)................................................................            11.03
             (c)................................................................            11.03
        313  (a)................................................................             7.06
             (b)(1).............................................................             N.A.
             (b)(2).............................................................             7.07
             (c)................................................................          7.06;11.02
             (d)................................................................             7.06
        314  (a)................................................................          4.03;11.02
             (b)................................................................             N.A.
             (c)(1).............................................................            11.04
             (c)(2).............................................................            11.04
             (c)(3).............................................................             N.A.
             (d)................................................................             N.A.
             (e)................................................................            11.05
             (f)................................................................             N.A.
        315  (a)................................................................             7.01
             (b)................................................................          7.05;11.02
             (c)................................................................             7.01
             (d)................................................................             7.01
             (e)................................................................             6.11
        316  (a) (last sentence)................................................             2.09
             (a)(1)(A)..........................................................             6.05
             (a)(1)(B)..........................................................             6.04
             (a)(2).............................................................             N.A.
             (b)................................................................             6.07
             (c)................................................................             2.12
        317  (a)(1).............................................................             6.08
             (a)(2).............................................................             6.09
             (b)................................................................             2.04
        318  (a)................................................................            11.01
             (b)................................................................             N.A.
             (c)................................................................            11.01
</TABLE>

         N.A. means not applicable.
         * This Cross Reference Table is not part of the Indenture.
<PAGE>

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                               Page
<S>                                                                                                            <C>
                                                           ARTICLE 1
                                                 DEFINITIONS AND INCORPORATION
                                                         BY REFERENCE

Section 1.01.      Definitions...................................................................................    1

Section 1.02.      Other Definitions.............................................................................   21

Section 1.03.      Incorporation by Reference of Trust Indenture Act.............................................   21

Section 1.04.      Rules of Construction.........................................................................   22


                                                           ARTICLE 2
                                                           THE NOTES

Section 2.01.      Form and Dating...............................................................................   22

Section 2.02.      Execution and Authentication..................................................................   23

Section 2.03.      Registrar and Paying Agent....................................................................   23

Section 2.04.      Paying Agent to Hold Money in Trust...........................................................   24

Section 2.05.      Holder Lists..................................................................................   24

Section 2.06.      Transfer and Exchange.........................................................................   24

Section 2.07.      Replacement Notes.............................................................................   35

Section 2.08.      Outstanding Notes.............................................................................   36

Section 2.09.      Treasury Notes................................................................................   36

Section 2.10.      Temporary Notes...............................................................................   36

Section 2.11.      Cancellation..................................................................................   36

Section 2.12.      Defaulted Interest............................................................................   37


                                                             ARTICLE 3
                                                      REDEMPTION AND PREPAYMENT

Section 3.01.      Notices to Trustee............................................................................   37

Section 3.02.      Selection of Notes to Be Redeemed.............................................................   37

Section 3.03.      Notice of Redemption..........................................................................   38

Section 3.04.      Effect of Notice of Redemption................................................................   38

Section 3.05.      Deposit of Redemption Price...................................................................   38

Section 3.06.      Notes Redeemed in Part........................................................................   39

Section 3.07.      Optional Redemption...........................................................................   39

Section 3.08.      Mandatory Redemption..........................................................................   40
</TABLE>

                                       i
<PAGE>

<TABLE>
<S>                                                                                                                 <C>
Section 3.09.      Offer to Purchase by Application of Excess Proceeds...........................................   40


                                                       ARTICLE 4
                                                       COVENANTS

Section 4.01.      Payment of Notes..............................................................................   42

Section 4.02.      Maintenance of Office or Agency...............................................................   42

Section 4.03.      Reports.......................................................................................   42

Section 4.04.      Compliance Certificate........................................................................   43

Section 4.05.      Taxes.........................................................................................   44

Section 4.06.      Stay, Extension and Usury Laws................................................................   44

Section 4.07.      Restricted Payments...........................................................................   44

Section 4.08.      Dividend and Other Payment Restrictions Affecting Subsidiaries................................   48

Section 4.09.      Incurrence of Indebtedness and Issuance of Preferred Stock....................................   49

Section 4.10.      Asset Sales...................................................................................   52

Section 4.11.      Transactions with Affiliates..................................................................   54

Section 4.12.      Liens.........................................................................................   55

Section 4.13.      Business Activities...........................................................................   55

Section 4.14.      Corporate Existence...........................................................................   55

Section 4.15.      Offer to Repurchase Upon Change of Control....................................................   55

Section 4.16.      Sale and Leaseback Transactions...............................................................   57

Section 4.17.      Limitation on Issuances and Sales of Capital Stock of Restricted Subsidiaries.................   57

Section 4.18.      Limitation on Issuances of Guarantees of Indebtedness.........................................   58


                                                       ARTICLE 5
                                                       SUCCESSORS

Section 5.01.      Merger, Consolidation, or Sale of Assets......................................................   58

Section 5.02.      Successor Corporation Substituted.............................................................   59


                                                         ARTICLE 6
                                                    DEFAULTS AND REMEDIES

Section 6.01.      Events of Default.............................................................................   60

Section 6.02.      Acceleration..................................................................................   61

Section 6.03.      Other Remedies................................................................................   61

Section 6.04.      Waiver of Past Defaults.......................................................................   62

Section 6.05.      Control by Majority...........................................................................   62
</TABLE>

                                      ii
<PAGE>

<TABLE>
<S>                                                                                                                   <C>
Section 6.06.      Limitation on Suits..............................................................................  62

Section 6.07.      Rights of Holders of Notes to Receive Payment....................................................  62

Section 6.08.      Collection Suit by Trustee.......................................................................  63

Section 6.09.      Trustee May File Proofs of Claim.................................................................  63

Section 6.10.      Priorities.......................................................................................  63

Section 6.11.      Undertaking for Costs............................................................................  64


                                                            ARTICLE 7
                                                             TRUSTEE

Section 7.01.      Duties of Trustee................................................................................  64

Section 7.02.      Rights of Trustee................................................................................  65

Section 7.03.      Individual Rights of Trustee.....................................................................  65

Section 7.04.      Trustee's Disclaimer.............................................................................  66

Section 7.05.      Notice of Defaults...............................................................................  66

Section 7.06.      Reports by Trustee to Holders of the Notes.......................................................  66

Section 7.07.      Compensation and Indemnity.......................................................................  66

Section 7.08.      Replacement of Trustee...........................................................................  67

Section 7.09.      Successor Trustee by Merger, etc.................................................................  68

Section 7.10.      Eligibility; Disqualification....................................................................  68

Section 7.11.      Preferential Collection of Claims Against Company................................................  68


                                                             ARTICLE 8
                                               LEGAL DEFEASANCE AND COVENANT DEFEASANCE

Section 8.01.      Option to Effect Legal Defeasance or Covenant Defeasance.........................................  68

Section 8.02.      Legal Defeasance and Discharge...................................................................  69

Section 8.03.      Covenant Defeasance..............................................................................  69

Section 8.04.      Conditions to Legal or Covenant Defeasance.......................................................  70

Section 8.05.      Deposited Money and Government Securities to be Held in Trust; Other Miscellaneous Provisions....  71

Section 8.06.      Repayment to Company.............................................................................  71

Section 8.07.      Reinstatement....................................................................................  72


                                                              ARTICLE 9
                                                   AMENDMENT, SUPPLEMENT AND WAIVER

Section 9.01.      Without Consent of Holders of Notes..............................................................  72
</TABLE>

                                      iii
<PAGE>

<TABLE>
<S>                                                                                                                 <C>
Section 9.02.      With Consent of Holders of Notes..............................................................   73

Section 9.03.      Compliance with Trust Indenture Act...........................................................   74

Section 9.04.      Revocation and Effect of Consents.............................................................   74

Section 9.05.      Notation on or Exchange of Notes..............................................................   74

Section 9.06.      Trustee to Sign Amendments, etc...............................................................   75


                                                           ARTICLE 10
                                                        NOTE GUARANTEES

Section 10.01.     Guarantee.....................................................................................   75

Section 10.02.     Limitation on Guarantor Liability.............................................................   76

Section 10.03.     Execution and Delivery of Note Guarantee......................................................   76

Section 10.04.     Guarantors May Consolidate, etc., on Certain Terms............................................   77

Section 10.05.     Releases Following Sale of Assets.............................................................   77


                                                           ARTICLE 11
                                                          MISCELLANEOUS

Section 11.01.     Trust Indenture Act Controls..................................................................   78

Section 11.02.     Notices.......................................................................................   78

Section 11.03.     Communication by Holders of Notes with Other Holders of Notes.................................   79

Section 11.04.     Certificate and Opinion as to Conditions Precedent............................................   79

Section 11.05.     Statements Required in Certificate or Opinion.................................................   79

Section 11.06.     Rules by Trustee and Agents...................................................................   80

Section 11.07.     No Personal Liability of Directors, Officers, Employees and Stockholders......................   80

Section 11.08.     Governing Law.................................................................................   80

Section 11.09.     No Adverse Interpretation of Other Agreements.................................................   80

Section 11.10.     Successors....................................................................................   80

Section 11.11.     Severability..................................................................................   81

Section 11.12.     Counterpart Originals.........................................................................   81

Section 11.13.     Table of Contents, Headings, etc..............................................................   81
</TABLE>

                                      iv
<PAGE>

                                    EXHIBITS

Exhibit A         FORM OF NOTE
Exhibit B         FORM OF CERTIFICATE OF TRANSFER
Exhibit C         FORM OF CERTIFICATE OF EXCHANGE
Exhibit D         FORM OF CERTIFICATE FROM ACQUIRING INSTITUTIONAL ACCREDITED
                  INVESTOR
Exhibit E         FORM OF SUPPLEMENTAL INDENTURE TO BE DELIVERED BY SUBSEQUENT
                  GUARANTORS
Exhibit F         FORM OF NOTATION OF GUARANTEE

                                       v
<PAGE>

         INDENTURE dated as of May 16, 2001 between Crown Castle International
Corp., a Delaware corporation (the "Company"), and The Bank of New York, a New
York banking corporation, as trustee (the "Trustee").

         The Company and the Trustee agree as follows for the benefit of each
other and for the equal and ratable benefit of the Holders of the 9 3/8% Senior
Notes due 2011 (each, a "Note", and, collectively, the "Notes"):

ARTICLE 1
                          DEFINITIONS AND INCORPORATION
                                  BY REFERENCE

Section 1.01. Definitions.

         "10-3/8% Senior Discount Notes" means the Company's 10-3/8% Senior
Discount Notes due 2011.

         "144A Global Note" means a global note substantially in the form of
Exhibit A hereto bearing the Global Note Legend and the Private Placement Legend
and deposited with or on behalf of, and registered in the name of, the
Depositary or its nominee that will be issued in a denomination equal to the
outstanding principal amount of the Notes sold in reliance on Rule 144A.

         "Acquired Debt" means, with respect to any specified Person:

         (1)  Indebtedness of any other Person existing at the time such other
              Person is merged with or into or became a Subsidiary of such
              specified Person, including, without limitation, Indebtedness
              incurred in connection with, or in contemplation of, such other
              Person merging with or into or becoming a Subsidiary of such
              specified Person; and

         (2)  Indebtedness secured by a Lien encumbering any asset acquired by
              such specified Person.

         "Additional Notes" means up to $100.00 million in aggregate principal
amount of Notes issued under this Indenture, in accordance with Sections 2.02
and 4.09 hereof.

         "Adjusted Consolidated Cash Flow" means, as of any date of
determination, the sum of:

         (1)  the Consolidated Cash Flow of the Company for the four most recent
              full fiscal quarters ending immediately prior to such date for
              which internal financial statements are available, less the
              Company's Tower Cash Flow for such four-quarter period; plus

         (2)  the product of four times the Company's Tower Cash Flow for the
              most recent fiscal quarter for which internal financial statements
              are available.

For purposes of making the computation referred to above:

         (1)  acquisitions that have been made by the Company or any of its
              Restricted Subsidiaries, including through mergers or
              consolidations and including any related financing transactions,
              during the reference period or subsequent to such reference period
              and on

                                       1
<PAGE>

              or prior to the calculation date shall be deemed to have
              occurred on the first day of the reference period and Consolidated
              Cash Flow for such reference period shall be calculated without
              giving effect to clause (2) of the proviso set forth in the
              definition of Consolidated Net Income;

         (2)  the Consolidated Cash Flow attributable to discontinued
              operations, as determined in accordance with GAAP, and operations
              or businesses disposed of prior to the calculation date, shall be
              excluded; and

         (3)  the corporate development expense of the Company and its
              Restricted Subsidiaries calculated in a manner consistent with the
              audited financial statements of the Company included in the
              Offering Memorandum shall be added to Consolidated Cash Flow to
              the extent it was included in computing Consolidated Net Income.

         "Affiliate" of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified Person. For purposes of this definition, "control"
(including, with correlative meanings, the terms "controlling," "controlled by"
and "under common control with"), as used with respect to any Person, shall mean
the possession, directly or indirectly, of the power to direct or cause the
direction of the management or policies of such Person, whether through the
ownership of voting securities, by agreement or otherwise; provided that
beneficial ownership of 10% or more of the Voting Stock of a Person shall be
deemed to be control.

         "Agent" means any Registrar, Paying Agent or co-registrar.

         "Applicable Procedures" means, with respect to any transfer or exchange
of or for beneficial interests in any Global Note, the rules and procedures of
the Depositary, Euroclear and Clearstream that apply to such transfer or
exchange.

         "Asset Sale" means:

         (1)  the sale, lease, conveyance or other disposition of any assets or
              rights (including, without limitation, by way of a sale and
              leaseback); provided that the sale, lease, conveyance or other
              disposition of all or substantially all of the assets of the
              Company and its Subsidiaries taken as a whole will be governed by
              the Section 4.15 and Article 5 hereof and not by Section 4.10
              hereof; and

         (2)  the issue or sale by the Company or any of its Restricted
              Subsidiaries of Equity Interests of any of the Company's
              Subsidiaries (other than directors' qualifying shares or shares
              required by applicable law to be held by a Person other than the
              Company or a Restricted Subsidiary), in the case of either clause
              (1) or (2), whether in a single transaction or a series of related
              transactions:

              (a)  that have a fair market value in excess of $1.0 million; or

              (b)  for net proceeds in excess of $1.0 million.

         Notwithstanding the foregoing, the following items shall not be deemed
to be Asset Sales:

                                       2
<PAGE>

         (1)  a transfer of assets by the Company to a Restricted Subsidiary or
              by a Restricted Subsidiary to the Company or to another Restricted
              Subsidiary;

         (2)  an issuance of Equity Interests by a Subsidiary to the Company or
              to another Restricted Subsidiary;

         (3)  a transfer or issuance of Equity Interests of an Unrestricted
              Subsidiary to an Unrestricted Subsidiary; provided, however, that
              such transfer or issuance does not result in a decrease in the
              percentage of ownership of the voting securities of such
              transferee Unrestricted Subsidiary that are collectively held by
              the Company and its Subsidiaries;

         (4)  a Restricted Payment that is permitted by Section 4.07 hereof;

         (5)  grants of leases or licenses in the ordinary course of business;
              and

         (6)  disposals of Cash Equivalents.

         "Attributable Debt" in respect of a sale and leaseback transaction
means, at the time of determination, the present value (discounted at the rate
of interest implicit in such transaction, determined in accordance with GAAP) of
the obligation of the lessee for net rental payments during the remaining term
of the lease included in such sale and leaseback transaction (including any
period for which such lease has been extended or may, at the option of the
lessor, be extended).

         "August 1999 Senior Note Indenture" means that certain indenture dated
as of August 3, 1999 between the Company and the United States Trust Company of
New York, as Trustee, governing the Company's 9 1/2% Senior Notes due 2011.

         "Bankruptcy Law" means Title 11, U.S. Code or any similar federal or
state law for the relief of debtors.

         "Board of Directors" means the Board of Directors of the Company, or
any authorized committee of the Board of Directors.

         "Broker-Dealer" means any broker or dealer registered under the
Exchange Act.

         "Business Day" means any day other than a Legal Holiday.

         "Capital Lease Obligation" means, at the time any determination thereof
is to be made, the amount of the liability in respect of a capital lease that
would at such time be required to be capitalized on a balance sheet in
accordance with GAAP.

         "Capital Stock" means:

         (1)  in the case of a corporation, corporate stock;

         (2)  in the case of an association or business entity, any and all
              shares, interests, participations, rights or other equivalents
              (however designated) of corporate stock;

                                       3
<PAGE>

         (3)  in the case of a partnership or limited liability company,
              partnership or membership interests (whether general or limited);
              and

         (4)  any other interest or participation that confers on a Person the
              right to receive a share of the profits and losses of, or
              distributions of assets of, the issuing Person.

         "Cash Equivalents" means:

         (1)  United States dollars;

         (2)  securities issued or directly and fully guaranteed or insured by
              the United States government or any agency or instrumentality
              thereof (provided that the full faith and credit of the United
              States is pledged in support thereof) having maturities of not
              more than six months from the date of acquisition;

         (3)  certificates of deposit and eurodollar time deposits with
              maturities of six months or less from the date of acquisition,
              bankers' acceptances with maturities not exceeding six months and
              overnight bank deposits, in each case with any lender party to the
              Senior Credit Facility or with any domestic commercial bank having
              capital and surplus in excess of $500.0 million and a Thompson
              Bank Watch Rating of "B" or better;

         (4)  repurchase obligations with a term of not more than seven days for
              underlying securities of the types described in clauses (2) and
              (3) above entered into with any financial institution meeting the
              qualifications specified in clause (3) above;

         (5)  commercial paper having the highest rating obtainable from Moody's
              Investors Service, Inc. or Standard & Poor's Ratings Group and in
              each case maturing within six months after the date of
              acquisition; and

         (6)  money market funds at least 95% of the assets of which constitute
              Cash Equivalents of the kinds described in clauses (1)-(5) of this
              definition.

         "CCAIC" means CCA Investment Corp., which is an indirect wholly owned
Subsidiary of the Company and was formed to hold the Company's Equity Interests
in Crown Atlantic Holding Company LLC.

         "Change of Control" means the occurrence of any of the following:

         (1)  the sale, lease, transfer, conveyance or other disposition (other
              than by way of merger or consolidation), in one or a series of
              related transactions, of all or substantially all of the assets of
              the Company and its Restricted Subsidiaries, taken as a whole to
              any "person" (as such term is used in Section 13(d)(3) of the
              Exchange Act) other than a Principal or a Related Party of a
              Principal;

         (2)  the adoption of a plan relating to the liquidation or dissolution
              of the Company;

         (3)  the consummation of any transaction (including, without
              limitation, any merger or consolidation) the result of which is
              that any "person" (as defined above), other than the Principals
              and their Related Parties, becomes the "beneficial owner" (as such
              term is

                                       4
<PAGE>

              defined in Rule 13d-3 and Rule 13d-5 under the Exchange Act,
              except that a person shall be deemed to have "beneficial
              ownership" of all securities that such person has the right to
              acquire, whether such right is currently exercisable or is
              exercisable only upon the occurrence of a subsequent condition),
              directly or indirectly, of more than 50% of the Voting Stock of
              the Company (measured by voting power rather than number of
              shares); provided that transfers of Equity Interests in the
              Company between or among the beneficial owners of the Company's
              Equity Interests and/or Equity Interests in CTSH, in each case as
              of the date hereof, will not be deemed to cause a Change of
              Control under this clause (3) so long as no single Person together
              with its Affiliates acquires a beneficial interest in more of the
              Voting Stock of the Company than is at the time collectively
              beneficially owned by the Principals and their Related Parties;

         (4)  the first day on which a majority of the members of the Board of
              Directors are not Continuing Directors; or

         (5)  the Company consolidates with, or merges with or into, any Person,
              or any Person consolidates with, or merges with or into, the
              Company, in any such event pursuant to a transaction in which any
              of the outstanding Voting Stock of the Company is converted into
              or exchanged for cash, securities or other property, other than
              any such transaction where:

              (a)  the Voting Stock of the Company outstanding immediately prior
                   to such transaction is converted into or exchanged for Voting
                   Stock (other than Disqualified Stock) of the surviving or
                   transferee Person constituting a majority of the outstanding
                   shares of such Voting Stock of such surviving or transferee
                   Person (immediately after giving effect to such issuance); or

              (b)  the Principals and their Related Parties own a majority of
                   such outstanding shares after such transaction.

         "Clearstream" means Clearstream Banking S.A.

         "Company" means Crown Castle International Corp., and any and all
         successors thereto.

         "Completed Tower" means any wireless transmission tower owned or
managed by the Company or any of its Restricted Subsidiaries that, as of any
date of determination:

         (1)  has at least one wireless communications or broadcast tenant that
              has executed a definitive lease with the Company or any of its
              Restricted Subsidiaries, which lease is producing revenue with
              respect to the tower as of the date of determination; and

         (2)  has capacity for at least two tenants in addition to the tenant
              referred to in clause (1) of this definition.

                                       5
<PAGE>

         "Consolidated Cash Flow" means, with respect to any Person for any
period, the Consolidated Net Income of such Person for such period; plus

         (1)  provision for taxes based on income or profits of such Person and
              its Restricted Subsidiaries for such period, to the extent that
              such provision for taxes was included in computing such
              Consolidated Net Income; plus

         (2)  consolidated interest expense of such Person and its Restricted
              Subsidiaries for such period, whether paid or accrued and whether
              or not capitalized (including, without limitation, amortization of
              debt issuance costs and original issue discount, non-cash interest
              payments, the interest component of any deferred payment
              obligations, the interest component of all payments associated
              with Capital Lease Obligations, commissions, discounts and other
              fees and charges incurred in respect of letters of credit or
              bankers' acceptance financings, and net payments (if any) pursuant
              to Hedging Obligations), to the extent that any such expense was
              deducted in computing such Consolidated Net Income; plus

         (3)  depreciation, amortization (including amortization of goodwill and
              other intangibles and other non-cash expenses (excluding any such
              non-cash expense to the extent that it represents an accrual of or
              reserve for cash expenses in any future period) of such Person and
              its Restricted Subsidiaries for such period to the extent that
              such depreciation, amortization and other non-cash expenses were
              deducted in computing such Consolidated Net Income; minus

         (4)  non-cash items increasing such Consolidated Net Income for such
              period (excluding any items that were accrued in the ordinary
              course of business),

in each case on a consolidated basis and determined in accordance with GAAP.

         "Consolidated Indebtedness" means, with respect to any Person as of any
date of determination, the sum, without duplication, of

         (1)  the total amount of Indebtedness of such Person and its Restricted
              Subsidiaries; plus

         (2)  the total amount of Indebtedness of any other Person, to the
              extent that such Indebtedness has been Guaranteed by the referent
              Person or one or more of its Restricted Subsidiaries; plus

         (3)  the aggregate liquidation value of all Disqualified Stock of such
              Person and all preferred stock of Restricted Subsidiaries of such
              Person, in each case, determined on a consolidated basis in
              accordance with GAAP.

         "Consolidated Interest Expense" means, with respect to any Person for
any period:

         (1)  the consolidated interest expense of such Person and its
              Restricted Subsidiaries for such period determined in accordance
              with GAAP, whether paid or accrued and whether or not capitalized
              (including, without limitation, amortization of debt issuance
              costs and original issue discount, non-cash interest payments, the
              interest component of any deferred payment obligations, the
              interest component of all payments associated with

                                       6
<PAGE>

              Capital Lease Obligations, imputed interest with respect to
              Attributable Debt, commissions, discounts and other fees and
              charges incurred in respect of letter of credit or bankers'
              acceptance financings, and net payments, if any, pursuant to
              Hedging Obligations); plus

         (2)  all preferred stock dividends paid or accrued in respect of the
              Company's and its Restricted Subsidiaries' preferred stock to
              Persons other than the Company or a Wholly Owned Restricted
              Subsidiary of the Company other than preferred stock dividends
              paid by the Company in shares of preferred stock that is not
              Disqualified Stock.

         "Consolidated Net Income" means, with respect to any Person for any
period, the aggregate of the Net Income of such Person and its Restricted
Subsidiaries for such period, on a consolidated basis, determined in accordance
with GAAP; provided that

         (1)  the Net Income (but not loss) of any Person other than the Company
              that is not a Restricted Subsidiary or that is accounted for by
              the equity method of accounting shall be included only to the
              extent of the amount of dividends or distributions paid in cash to
              the referent Person or a Restricted Subsidiary thereof;

         (2)  the Net Income of any Person acquired in a pooling of interests
              transaction for any period prior to the date of such acquisition
              shall be excluded;

         (3)  the cumulative effect of a change in accounting principles shall
              be excluded; and

         (4)  the Net Income (but not loss) of any Unrestricted Subsidiary shall
              be excluded whether or not distributed to the Company or one of
              its Restricted Subsidiaries.

         "Consolidated Tangible Assets" means, with respect to the Company, the
total consolidated assets of the Company and its Restricted Subsidiaries, less
the total intangible assets of the Company and its Restricted Subsidiaries, as
shown on the most recent internal consolidated balance sheet of the Company and
such Restricted Subsidiaries calculated on a consolidated basis in accordance
with GAAP.

         "Continuing Directors" means, as of any date of determination, any
member of the Board of Directors who:

         (1)  was a member of such Board of Directors on the date of the August
              1999 Senior Note Indenture;

         (2)  was nominated for election or elected to such Board of Directors
              with the approval of a majority of the Continuing Directors who
              were members of such Board of Directors at the time of such
              nomination or election; or

         (3)  is a designee of a Principal or was nominated by a Principal.

         "Corporate Trust Office of the Trustee" shall be at the address of the
Trustee specified in Section 11.02 hereof or such other address as to which the
Trustee may give notice to the Company.

         "Credit Facilities" means one or more debt facilities (including,
without limitation, the Senior Credit Facility) or commercial paper facilities
with banks or other institutional lenders providing for

                                       7
<PAGE>

revolving credit loans, term loans, receivables financing (including through the
sale of receivables to such lenders or to special purpose entities formed to
borrow from such lenders against such receivables) or letters of credit, in each
case, as amended, restated, modified, renewed, refunded, replaced or refinanced
in whole or in part from time to time.

         "CTI" means Crown Castle UK Limited, formerly known as Castle
Transmission International Limited.

         "CTSH" means Crown Castle UK Holdings Limited, formerly known as Crown
Transmission Services (Holdings) Ltd, and its successors.

         "Custodian" means the Trustee, as Custodian with respect to the Notes
in global form, or any successor entity thereto.

         "Debt to Adjusted Consolidated Cash Flow Ratio" means, as of any date
of determination, the ratio of:

         (1)  the Consolidated Indebtedness of the Company as of such date to

         (2)  the Adjusted Consolidated Cash Flow of the Company as of such
              date.

         "Default" means any event that is, or with the passage of time or the
giving of notice or both would be, an Event of Default.

         "Definitive Note" means a certificated Note registered in the name of
the Holder thereof and issued in accordance with Section 2.06 hereof,
substantially in the form of Exhibit A hereto except that such Note shall not
bear the Global Note Legend and shall not have the "Schedule of Exchanges of
Interests in the Global Note" attached thereto.

         "Depositary" means, with respect to the Notes issuable or issued in
whole or in part in global form, the Person specified in Section 2.03 hereof as
the Depositary with respect to the Notes, and any and all successors thereto
appointed as depositary hereunder and having become such pursuant to the
applicable provision of this Indenture.

         "Disqualified Stock" means any Capital Stock that, by its terms (or by
the terms of any security into which it is convertible or for which it is
exchangeable, in each case, at the option of the holder thereof), or upon the
happening of any event, matures or is mandatorily redeemable, pursuant to a
sinking fund obligation or otherwise, or redeemable at the option of the holder
thereof, in whole or in part, on or prior to the date that is 91 days after the
date on which the Notes mature; provided, however, that any Capital Stock that
would constitute Disqualified Stock solely because the holders thereof have the
right to require the Company to repurchase such Capital Stock upon the
occurrence of a Change of Control or an Asset Sale shall not constitute
Disqualified Stock if the terms of such Capital Stock provide that the Company
may not repurchase or redeem any such Capital Stock pursuant to such provisions
unless such repurchase or redemption complies with Section 4.07 hereof.

         "Eligible Indebtedness" means any Indebtedness other than:

         (1)  Indebtedness in the form of, or represented by, bonds or other
              securities or any guarantee thereof; and

                                       8
<PAGE>

         (2)  Indebtedness that is, or may be, quoted, listed or purchased and
              sold on any stock exchange, automated trading system or over-the-
              counter or other securities market (including, without prejudice
              to the generality of the foregoing, the market for securities
              eligible for resale pursuant to Rule 144A under the Securities
              Act).

         "Equity Interests" means Capital Stock and all warrants, options or
other rights to acquire Capital Stock (but excluding any debt security that is
convertible into, or exchangeable for, Capital Stock).

         "Euroclear" means Morgan Guaranty Trust Company of New York, Brussels
office, as operator of the Euroclear system.

         "Exchange Act" means the Securities Exchange Act of 1934, as amended.

         "Exchange Notes" means the Notes issued in the Exchange Offer pursuant
to Section 2.06(f) hereof.

         "Exchange Offer" has the meaning set forth in the Registration Rights
Agreement.

         "Exchange Offer Registration Statement" has the meaning set forth in
the Registration Rights Agreement.

         "Existing Indebtedness" means Indebtedness of the Company and its
Subsidiaries (other than Indebtedness under the Senior Credit Facility) in
existence on August 3, 1999, until such amounts are repaid.

         "GAAP" means generally accepted accounting principles set forth in the
opinions and pronouncements of the Accounting Principles Board of the American
Institute of Certified Public Accountants and statements and pronouncements of
the Financial Accounting Standards Board or in such other statements by such
other entity as have been approved by a significant segment of the accounting
profession, which are in effect on the date hereof.

         "Global Note Legend" means the legend set forth in Section 2.06(g)(ii),
which is required to be placed on all Global Notes issued under this Indenture.

         "Global Notes" means, individually and collectively, each of the
Restricted Global Notes and the Unrestricted Global Notes, substantially in the
form of Exhibit A hereto issued in accordance with Section 2.01, 2.06(b)(iv),
2.06(d)(ii) or 2.06(f) hereof.

         "Governance Agreement" means the agreement among the Company, TdF and
its affiliates, dated as of August 21, 1998, to provide for certain rights and
obligations of the Company, TdF and its affiliates with respect to the
management of the Company.

         "Government Securities" means direct obligations of, or obligations
guaranteed by, the United States of America, and the payment for which the
United States pledges its full faith and credit.

         "Guarantee" means a guarantee (other than by endorsement of negotiable
instruments for collection in the ordinary course of business), direct or
indirect, in any manner (including, without limitation, by way of a pledge of
assets or through letters of credit or reimbursement agreements in

                                       9
<PAGE>

respect thereof), of all or any part of any Indebtedness. The term "Guarantor"
shall mean any Person Guaranteeing any obligation.

         "Hedging Obligations" means, with respect to any Person, the
obligations of such Person under:

         (1)  interest rate swap agreements, interest rate cap agreements and
              interest rate collar agreements; and

         (2)  other agreements or arrangements designed to protect such Person
              against fluctuations in interest rates or currency exchange rates.

         "Holder" means a Person in whose name a Note is registered.

         "IAI Global Note" means the Global Note substantially in the form of
Exhibit A hereto bearing the Global Note Legend and the Private Placement Legend
and deposited with or on behalf of and registered in the name of the Depositary
or its nominee that will be issued in a denomination equal to the outstanding
principal amount of the Notes sold to Institutional Accredited Investors.

         "Indebtedness" means, with respect to any Person, any indebtedness of
such Person, whether or not contingent, in respect of borrowed money or
evidenced by bonds, notes, debentures or similar instruments or letters of
credit (or reimbursement agreements in respect thereof) or banker's acceptances
or representing Capital Lease Obligations or the balance deferred and unpaid of
the purchase price of any property or representing any Hedging Obligations,
except any such balance that constitutes an accrued expense or trade payable, if
and to the extent any of the foregoing indebtedness (other than letters of
credit and Hedging Obligations) would appear as a liability upon a balance sheet
of such Person prepared in accordance with GAAP, as well as all Indebtedness of
others secured by a Lien on any asset of such Person whether or not such
Indebtedness is assumed by such Person (the amount of such Indebtedness as of
any date being deemed to be the lesser of the value of such property or assets
as of such date or the principal amount of such Indebtedness of such other
Person so secured) and, to the extent not otherwise included, the Guarantee by
such Person of any Indebtedness of any other Person. The amount of any
Indebtedness outstanding as of any date shall be:

         (1)  the accreted value thereof, in the case of any Indebtedness issued
              with original issue discount; and

         (2)  the principal amount thereof, together with any interest thereon
              that is more than 30 days past due, in the case of any other
              Indebtedness.

         "Indenture" means this Indenture, as amended or supplemented from time
to time.

         "Indirect Participant" means a Person who holds a beneficial interest
in a Global Note through a Participant.

         "Initial Notes" means the first $450 million aggregate principal amount
of Notes issued under this Indenture on the date hereof.

         "Initial Purchasers" means J.P. Morgan Securities Inc., Goldman, Sachs
& Co., Credit Suisse First Boston Corporation, Lehman Brothers Inc., Morgan
Stanley & Co. Incorporated, BNY Capital

                                       10
<PAGE>

Markets, Inc., Scotia Capital (USA) Inc., and The Royal Bank of Scotland plc, as
purchasers of the Notes from the Company pursuant to the Purchase Agreement.

         "Institutional Accredited Investor" means an institution that is an
"accredited investor" as defined in Rule 501(a)(1), (2), (3) or (7) under the
Securities Act, who are not also QIBs.

         "Investments" means, with respect to any Person, all investments by
such Person in other Persons (including Affiliates) in the forms of direct or
indirect loans (including guarantees of Indebtedness or other obligations),
advances or capital contributions (excluding commission, travel and similar
advances to officers and employees made in the ordinary course of business),
purchases or other acquisitions for consideration of Indebtedness, Equity
Interests or other securities, together with all items that are or would be
classified as investments on a balance sheet prepared in accordance with GAAP.
If the Company or any Restricted Subsidiary of the Company sells or otherwise
disposes of any Equity Interests of any direct or indirect Subsidiary of the
Company or a Restricted Subsidiary of the Company issues any of its Equity
Interests such that, in each case, after giving effect to any such sale or
disposition, such Person is no longer a Restricted Subsidiary of the Company,
the Company shall be deemed to have made an Investment on the date of any such
sale or disposition equal to the fair market value of the Equity Interests of
such Subsidiary not sold or disposed of in an amount determined as provided in
the final paragraph of Section 4.07 hereof.

         "Legal Holiday" means a Saturday, a Sunday or a day on which banking
institutions in the City of New York or at a place of payment are authorized by
law, regulation or executive order to remain closed. If a payment date is a
Legal Holiday at a place of payment, payment may be made at that place on the
next succeeding day that is not a Legal Holiday, and no interest shall accrue on
such payment for the intervening period.

         "Lien" means, with respect to any asset, any mortgage, lien, pledge,
charge, security interest or encumbrance of any kind in respect of such asset,
whether or not filed, recorded or otherwise perfected under applicable law
(including any conditional sale or other title retention agreement, any lease in
the nature thereof, any option or other agreement to sell or give a security
interest in and any filing of or agreement to give any financing statement under
the Uniform Commercial Code (or equivalent statutes) of any jurisdiction).

         "May 1999 Senior Discount Note Indenture" means that certain indenture,
dated as of May 17, 1999, between the Company and the United States Trust
Company of New York, as trustee, governing the Company's 10-3/8% Senior Discount
Notes.

         "Net Income" means, with respect to any Person, the net income (loss)
of such Person, determined in accordance with GAAP and before any reduction in
respect of preferred stock dividends, excluding, however:

         (1)      any gain or loss, together with any related provision for
                  taxes on such gain or loss, realized in connection with:

                  (a)      any Asset Sale (including, without limitation,
                           dispositions pursuant to sale and leaseback
                           transactions); or

                                       11
<PAGE>

                  (b)      the disposition of any securities by such Person or
                           any of its Restricted Subsidiaries or the
                           extinguishment of any Indebtedness of such Person or
                           any of its Restricted Subsidiaries; and

         (2)      any extraordinary gain or loss, together with any related
                  provision for taxes on such extraordinary gain or loss.

         "Net Proceeds" means the aggregate cash proceeds received by the
Company or any of its Restricted Subsidiaries in respect of any Asset Sale
(including, without limitation, any cash received upon the sale or other
disposition of any non-cash consideration received in any Asset Sale), net of:

         (1)      the direct costs relating to such Asset Sale (including,
                  without limitation, legal, accounting and investment banking
                  fees, and sales commissions) and any relocation expenses
                  incurred as a result thereof;

         (2)      taxes paid or payable as a result thereof (after taking into
                  account any available tax credits or deductions and any tax
                  sharing arrangements);

         (3)      amounts required to be applied to the repayment of
                  Indebtedness (other than Indebtedness under a Credit Facility)
                  secured by a Lien on the asset or assets that were the subject
                  of such Asset Sale;

         (4)      all distributions and other payments required to be made to
                  minority interest holders in Restricted Subsidiaries as a
                  result of such Asset Sale;

         (5)      the deduction of appropriate amounts provided by the seller as
                  a reserve in accordance with GAAP against any liabilities
                  associated with the assets disposed of in such Asset Sale and
                  retained by the Company or any Restricted Subsidiary after
                  such Asset Sale; and

         (6)      without duplication, any reserves that Board of Directors
                  determines in good faith should be made in respect of the sale
                  price of such asset or assets for post closing adjustments;

provided that in the case of any reversal of any reserve referred to in clause
(5) or (6) above, the amount so reversed shall be deemed to be Net Proceeds from
an Asset Sale as of the date of such reversal.

         "Non-Recourse Debt" means Indebtedness:

         (1)      as to which neither the Company nor any of its Restricted
Subsidiaries:

                  (a)      provides credit support of any kind (including any
                           undertaking, agreement or instrument that would
                           constitute Indebtedness);

                  (b)      is directly or indirectly liable (as a guarantor or
                           otherwise); or

                  (c)      constitutes the lender;

         (2)      no default with respect to which (including any rights that
                  the holders thereof may have to take enforcement action
                  against an Unrestricted Subsidiary) would permit (upon


                                       12
<PAGE>

                  notice, lapse of time or both) any holder of any other
                  Indebtedness of the Company or any of its Restricted
                  Subsidiaries to declare a default on such other Indebtedness
                  or cause the payment thereof to be accelerated or payable
                  prior to its stated maturity; and

         (3)      as to which the lenders have been notified in writing that
                  they will not have any recourse to the stock or assets of the
                  Company or any of its Restricted Subsidiaries (except that
                  this clause (3) will not apply to any Indebtedness incurred by
                  CTSH and its Subsidiaries prior to the date CTSH became a
                  Subsidiary).

         "Non-U.S. Person" means a Person who is not a U.S. Person.

         "Notes" has the meaning assigned to it in the preamble to this
Indenture. The Initial Notes and the Additional Notes shall be treated as a
single class for all purposes under this Indenture.

         "Obligations" means any principal, interest, penalties, fees,
indemnifications, reimbursements, damages and other liabilities payable under
the documentation governing any Indebtedness.

         "Offering" means the offering of the Notes by the Company.

         "Offering Memorandum" means the Offering Memorandum dated May 10, 2001
relating to the offering of the Notes, including all amendments and all
materials incorporated by reference in such Offering Memorandum.

         "Officer" means, with respect to any Person, the Chairman of the Board,
the Chief Executive Officer, the President, the Chief Operating Officer, the
Chief Financial Officer, the Treasurer, any Assistant Treasurer, the Controller,
the Secretary or any Vice-President of such Person.

         "Officers' Certificate" means a certificate signed on behalf of the
Company by two Officers of the Company, one of whom must be the principal
executive officer, the principal financial officer, the treasurer or the
principal accounting officer of the Company, that meets the requirements of
Section 11.04 hereof.

         "Opinion of Counsel" means an opinion from legal counsel who is
reasonably acceptable to the Trustee, that meets the requirements of Section
11.04 hereof. The counsel may be an employee of or counsel to the Company, any
Subsidiary of the Company or the Trustee.

         "Participant" means, with respect to the Depositary, Euroclear or
Clearstream, a Person who has an account with the Depositary, Euroclear or
Clearstream, respectively (and, with respect to DTC, shall include Euroclear and
Clearstream).

         "Permitted Business" means any business conducted by the Company, its
Restricted Subsidiaries or CTSH and its Subsidiaries on the date hereof and any
other business related, ancillary or complementary to any such business.

         "Permitted Investment" means:

         (1)      any Investment in the Company or in a Restricted Subsidiary of
                  the Company;

         (2)      any Investment in Cash Equivalents;

                                       13
<PAGE>

         (3)      any Investment by the Company or any Restricted Subsidiary of
                  the Company in a Person, if as a result of such Investment:

                  (a)      such Person becomes a Restricted Subsidiary of the
                           Company; or

                  (b)      such Person is merged, consolidated or amalgamated
                           with or into, or transfers or conveys substantially
                           all of its assets to, or is liquidated into, the
                           Company or a Restricted Subsidiary of the Company;

         (4)      any Restricted Investment made as a result of the receipt of
                  non-cash consideration from an Asset Sale that was made
                  pursuant to and in compliance with Section 4.10 hereof;

         (5)      any acquisition of assets solely in exchange for the issuance
                  of Equity Interests (other than Disqualified Stock) of the
                  Company;

         (6)      receivables created in the ordinary course of business;

         (7)      loans or advances to employees made in the ordinary course of
                  business since the date of the August 1999 Senior Note
                  Indenture not to exceed $2.0 million at any one time
                  outstanding;

         (8)      securities and other assets received in settlement of trade
                  debts or other claims arising in the ordinary course of
                  business;

         (9)      purchases of additional Equity Interests in CTSH for cash
                  pursuant to the governance agreement as the same is in effect
                  on the date of the May 1999 Senior Discount Notes Indenture
                  for aggregate cash consideration not to exceed $20.0 million
                  since the beginning of the quarter during which the May 1999
                  Senior Discount Notes Indenture was executed;

         (10)     Investments since the date of the August 1999 Senior Note
                  Indenture of up to an aggregate of $100.0 million (each such
                  Investment being measured as of the date made and without
                  giving effect to subsequent changes in value); and

         (11)     other Investments in Permitted Businesses since the date of
                  the August 1999 Senior Note Indenture not to exceed an amount
                  equal to $10.0 million plus 10% of the Company's Consolidated
                  Tangible Assets at any one time outstanding (each such
                  Investment being measured as of the date made and without
                  giving effect to subsequent changes in value).

         "Permitted Liens" means:

         (1)      Liens securing Eligible Indebtedness of the Company under one
                  or more Credit Facilities that was permitted by the terms
                  hereof to be incurred;

         (2)      Liens securing any Indebtedness of any of the Company's
                  Restricted Subsidiaries that was permitted by the terms hereof
                  to be incurred;

         (3)      Liens in favor of the Company;

                                       14
<PAGE>

         (4)      Liens existing on the date of the August 1999 Senior Note
                  Indenture;

         (5)      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 promptly instituted and
                  diligently concluded; provided that any reserve or other
                  appropriate provision as shall be required in conformity with
                  GAAP shall have been made therefor;

         (6)      Liens securing Indebtedness permitted to be incurred under
                  clause (5) of the second paragraph of Section 4.09 hereof; and

         (7)      Liens incurred in the ordinary course of business of the
                  Company or any Restricted Subsidiary of the Company since the
                  date of the August 1999 Senior Note Indenture with respect to
                  obligations that do not exceed $5.0 million at any one time
                  outstanding and that:

                  (a)      are not incurred in connection with the borrowing of
                           money or the obtaining of advances or credit (other
                           than trade credit in the ordinary course of
                           business); and

                  (b)      do not in the aggregate materially detract from the
                           value of the property or materially impair the use
                           thereof in the operation of business by the Company
                           or such Restricted Subsidiary.

         "Permitted Refinancing Indebtedness" means any Indebtedness of the
Company or any of its Restricted Subsidiaries issued in exchange for, or the net
proceeds of which are used to extend, refinance, renew, replace, defease or
refund, other Indebtedness of the Company or any of its Restricted Subsidiaries
(other than intercompany Indebtedness); provided that:

         (1)      the principal amount (or initial accreted value, if
                  applicable) of such Permitted Refinancing Indebtedness does
                  not exceed the principal amount of (or accreted value, if
                  applicable), plus accrued interest on, the Indebtedness so
                  extended, refinanced, renewed, replaced, defeased or refunded
                  (plus the amount of expenses and prepayment premiums incurred
                  in connection therewith);

         (2)      such Permitted Refinancing Indebtedness has a final maturity
                  date later than the final maturity date of, and has a Weighted
                  Average Life to Maturity equal to or greater than the Weighted
                  Average Life to Maturity of, the Indebtedness being extended,
                  refinanced, renewed, replaced, defeased or refunded;

         (3)      if the Indebtedness being extended, refinanced, renewed,
                  replaced, defeased or refunded is subordinated in right of
                  payment to the Notes, such Permitted Refinancing Indebtedness
                  is subordinated in right of payment to the Notes on terms at
                  least as favorable to the Holders of Notes as those contained
                  in the documentation governing the Indebtedness being
                  extended, refinanced, renewed, replaced, defeased or refunded;
                  and

         (4)      such Indebtedness is incurred either by the Company or by the
                  Restricted Subsidiary who is the obligor on the Indebtedness
                  being extended, refinanced, renewed, replaced, defeased or
                  refunded.

                                       15
<PAGE>

         "Person" means any individual, corporation, partnership, joint venture,
association, joint-stock company, trust, unincorporated organization or
government or agency or political subdivision thereof (including any subdivision
or ongoing business of any such entity or substantially all of the assets of any
such entity, subdivision or business).

         "Principals" means Berkshire Fund III, Limited Partnership; Berkshire
Fund IV, Limited Partnership; Berkshire Investors LLC; Berkshire Partners LLC;
Centennial Fund IV, L.P.; Centennial Fund V, L.P.; Centennial Entrepreneurs Fund
V, L.P.; Nassau Capital Partners II, L.P.; and NAS Partners I, L.L.C. and any
Related Party of the foregoing.

         "Private Placement Legend" means the legend set forth in Section
2.06(g)(i) to be placed on all Notes issued under this Indenture except where
otherwise permitted by the provisions of this Indenture.

         "Public Equity Offering" means an underwritten primary public offering
of common stock of the Company pursuant to an effective registration statement
under the Securities Act.

         "Purchase Agreement" means the Purchase Agreement, dated as of May 10,
2001 between the Company and the Initial Purchasers.

         "QIB" means a "qualified institutional buyer" as defined in Rule 144A.

         "Registration Rights Agreement" means the Registration Rights
Agreement, dated as of May 16, 2001, by and among the Company and the other
parties named on the signature pages thereof, as such agreement may be amended,
modified or supplemented from time to time and, with respect to any Additional
Notes, one or more registration rights agreements between the Company and the
other parties thereto, as such agreement(s) may be amended, modified or
supplemented from time to time, relating to rights given by the Company to the
purchasers of Additional Notes to register such Additional Notes under the
Securities Act.

         "Regulation S" means Regulation S promulgated under the Securities Act.

         "Regulation S Global Note" means a global Note bearing the Private
Placement Legend and deposited with or on behalf of the Depositary and
registered in the name of the Depositary or its nominee, issued in a
denomination equal to the outstanding principal amount of the Notes initially
sold in reliance on Rule 903 of Regulation S.

         "Related Party" with respect to any Principal means:

         (1)      any controlling stockholder, 80% (or more) owned Subsidiary of
                  such Principal; or

         (2)      any trust, corporation, partnership or other entity, the
                  beneficiaries, stockholders, members, partners, owners or
                  Persons beneficially holding an 80% or more controlling
                  interest of which consist of such Principal and/or such other
                  Persons referred to in the immediately preceding clause (1).

         "Responsible Officer" with respect to the Trustee, means any officer
within the Corporate Trust Administration of the Trustee (or any successor group
of the Trustee) or any other officer of the Trustee customarily performing
functions similar to those performed by any of the above designated officers and

                                       16
<PAGE>

also means, with respect to a particular corporate trust matter, any other
officer to whom such matter is referred because of his knowledge of and
familiarity with the particular subject.

         "Restricted Definitive Note" means a Definitive Note bearing the
Private Placement Legend.

         "Restricted Global Note" means a Global Note bearing the Private
Placement Legend.

         "Restricted Investment" means an Investment other than a Permitted
Investment.

         "Restricted Period" means the 40-day restricted period as defined in
Regulation S.

         "Restricted Subsidiary" of a Person means any Subsidiary of the
referent Person that is not an Unrestricted Subsidiary.

         "Rule 144" means Rule 144 promulgated under the Securities Act.

         "Rule 144A" means Rule 144A promulgated under the Securities Act.

         "Rule 903" means Rule 903 promulgated under the Securities Act.

         "Rule 904" means Rule 904 promulgated the Securities Act.

         "SEC" means the Securities and Exchange Commission.

         "Securities Act" means the Securities Act of 1933, as amended.

         "Senior Credit Facility" means that certain Credit Agreement, dated as
of March 15, 2000, by and among The Chase Manhattan Bank, Key Corporate Capital,
Inc. The Bank of Nova Scotia, as agents for the several lenders, and Crown
Castle Operating Company and the Company, including any related notes,
guarantees, collateral documents, instruments and agreements executed in
connection therewith, and in each case as amended, modified, renewed, refunded,
replaced or refinanced from time to time.

         "Shelf Registration Statement" means the Shelf Registration Statement
as defined in the Registration Rights Agreement.

         "Significant Subsidiary" means, with respect to any Person, any
Restricted Subsidiary of such Person that would be a "significant subsidiary" of
such Person as defined in Article 1, Rule 1-02 of Regulation S-X, promulgated
pursuant to the Securities Act, as such Regulation is in effect on the date
hereof, except that all references to "10 percent" in Rule 1-02(w)(1), (2) and
(3) shall mean "5 percent" and that all Unrestricted Subsidiaries of the Company
shall be excluded from all calculations under Rule 1-02(w).

         "Special Interest" means all Special Interest (as defined in the
Registration Rights Agreement) then owing pursuant to Section 2(c) of the
Registration Rights Agreement.

         "Stated Maturity" means, with respect to any installment of interest or
principal on any series of Indebtedness, the date on which such payment of
interest or principal was scheduled to be paid in the original documentation
governing such Indebtedness, and shall not include any contingent obligations to

                                       17
<PAGE>

repay, redeem or repurchase any such interest or principal prior to the date
originally scheduled for the payment thereof.

         "Stockholders' Agreement" means the agreement among the Company and
certain stockholders of the Company, dated as of August 21, 1998, to provide for
certain rights and obligations of the Company and such stockholders with respect
to the governance of the Company and such stockholders' shares of Common Stock
and/or Class A Common Stock of the Company.

         "Strategic Equity Investment" means a cash contribution to the common
equity capital of the Company or a purchase from the Company of common Equity
Interests (other than Disqualified Stock), in either case by or from a Strategic
Equity Investor and for aggregate cash consideration of at least $50.0 million.

         "Strategic Equity Investor" means a Person engaged in a Permitted
Business whose Total Equity Market Capitalization exceeds $1.0 billion.

         "Subsidiary" means, with respect to any Person:

         (1)      any corporation, association or other business entity of which
                  more than 50% of the total voting power of shares of Capital
                  Stock entitled (without regard to the occurrence of any
                  contingency) to vote in the election of directors, managers or
                  trustees thereof is at the time owned or controlled, directly
                  or indirectly, by such Person or one or more of the other
                  Subsidiaries of that Person (or a combination thereof); and

         (2)      any partnership:

                  (a)      the sole general partner or the managing general
                           partner of which is such Person or a Subsidiary of
                           such Person; or

                  (b)      the only general partners of which are such Person or
                           one or more Subsidiaries of such Person (or any
                           combination thereof).

         "TdF" means TeleDiffusion de France International S.A.

         "TIA" means the Trust Indenture Act of 1939 (15 U.S.C. (S)(S).
77aaa-77bbbb) as in effect on the date on which this Indenture is qualified
under the TIA.

         "Total Equity Market Capitalization" of any Person means, as of any day
of determination, the sum of:

         (1)      the product of:

                  (a)      the aggregate number of outstanding primary shares of
                           common stock of such Person on such day (which shall
                           not include any options or warrants on, or securities
                           convertible or exchangeable into, shares of common
                           stock of such person); multiplied by

                                       18
<PAGE>

                  (b)      the average closing price of such common stock listed
                           on a national securities exchange or the Nasdaq
                           National Market System over the 20 consecutive
                           business days immediately preceding such day; plus

         (2)      the liquidation value of any outstanding shares of preferred
                  stock of such Person on such day.

         "Tower Asset Exchange" means any transaction in which the Company or
one of its Restricted Subsidiaries exchanges assets for Tower Assets and/or cash
or Cash Equivalents where the fair market value (evidenced by a resolution of
the Board of Directors set forth in an Officers' Certificate delivered to the
Trustee) of the Tower Assets and cash or Cash Equivalents received by the
Company and its Restricted Subsidiaries in such exchange is at least equal to
the fair market value of the assets disposed of in such exchange.

         "Tower Assets" means wireless transmission towers and related assets
that are located on the site of a transmission tower.

         "Tower Cash Flow" means, for any period, the Consolidated Cash Flow of
the Company and its Restricted Subsidiaries for such period that is directly
attributable to site rental revenue or license fees paid to lease or sublease
space on communication sites owned or leased by the Company, all determined on a
consolidated basis and in accordance with GAAP. Tower Cash Flow will not include
revenue or expenses attributable to non-site rental services provided by the
Company or any of its Restricted Subsidiaries to lessees of communication sites
or revenues derived from the sale of assets.

         "Trustee" means the party named as such above until a successor
replaces it in accordance with the applicable provisions of this Indenture and
thereafter means the successor serving hereunder.

         "Unrestricted Global Note" means a permanent global Note substantially
in the form of Exhibit A attached hereto that bears the Global Note Legend and
that has the "Schedule of Exchanges of Interests in the Global Note" attached
thereto, and that is deposited with or on behalf of and registered in the name
of the Depositary, representing a series of Notes that do not bear the Private
Placement Legend.

         "Unrestricted Definitive Note" means one or more Definitive Notes that
do not bear and are not required to bear the Private Placement Legend.

         "Unrestricted Subsidiary" means any Subsidiary of the Company that is
designated by the Board of Directors as an Unrestricted Subsidiary pursuant to a
board resolution; but only to the extent that such Subsidiary:

         (1)      has no Indebtedness other than Non-Recourse Debt;

         (2)      is not party to any agreement, contract, arrangement or
                  understanding with the Company or any Restricted Subsidiary of
                  the Company unless the terms of any such agreement, contract,
                  arrangement or understanding are no less favorable to the
                  Company or such Restricted Subsidiary than those that might be
                  obtained at the time from Persons who are not Affiliates of
                  the Company;

         (3)      is a Person with respect to which neither the Company nor any
                  of its Restricted Subsidiaries has any direct or indirect
                  obligation:

                                       19
<PAGE>

                  (a)      to subscribe for additional Equity Interests; or

                  (b)      to maintain or preserve such Person's financial
                           condition or to cause such Person to achieve any
                           specified levels of operating results;

         (4)      has not guaranteed or otherwise directly or indirectly
                  provided credit support for any Indebtedness of the Company or
                  any of its Restricted Subsidiaries; and

         (5)      has at least one director on its Board of Directors that is
                  not a director or executive officer of the Company or any of
                  its Restricted Subsidiaries and has at least one executive
                  officer that is not a director or executive officer of the
                  Company or any of its Restricted Subsidiaries.

         Any such designation by the Board of Directors shall be evidenced to
the Trustee by filing with the trustee a certified copy of the board resolution
giving effect to such designation and an Officers' Certificate certifying that
such designation complied with the foregoing conditions and was permitted by
Section 4.07 hereof. In addition, each Subsidiary of the Company that is an
"Unrestricted Subsidiary" as of the date hereof under the indentures relating to
the Company's existing indebtedness shall be an "Unrestricted Subsidiary" for
purposes of this Indenture. If, at any time, any Unrestricted Subsidiary would
fail to meet the foregoing requirements as an Unrestricted Subsidiary, it shall
thereafter cease to be an Unrestricted Subsidiary for purposes of this
Indenture, and any Indebtedness of that Subsidiary shall be deemed to be
incurred by a Restricted Subsidiary of the Company as of such date (and, if such
Indebtedness is not permitted to be incurred as of such date under Section 4.09
hereof, the Company shall be in default of Section 4.09 hereof). The Board of
Directors may at any time designate any Unrestricted Subsidiary to be a
Restricted Subsidiary; provided that the designation shall be deemed to be an
incurrence of Indebtedness by a Restricted Subsidiary of the Company of any
outstanding Indebtedness of such Unrestricted Subsidiary and the designation
shall only be permitted if (1) such Indebtedness is permitted under Section 4.09
hereof, calculated on a pro forma basis as if such designation had occurred at
the beginning of the four-quarter reference period and (2) no Default would
occur or be in existence following such designation.

         "U.S. Person" means a U.S. person as defined in Rule 902(o) under the
Securities Act.

         "Voting Stock" of any Person as of any date means the Capital Stock of
such Person that is at the time entitled to vote in the election of the board of
directors of such Person.

         "Weighted Average Life to Maturity" means, when applied to any
Indebtedness at any date, the number of years obtained by dividing:

         (1)      the sum of the products obtained by multiplying :

                  (a)      the amount of each then remaining installment,
                           sinking fund, serial maturity or other required
                           payments of principal, including payment at final
                           maturity, in respect thereof; by

                  (b)      the number of years (calculated to the nearest one-
                           twelfth) that will elapse between such date and the
                           making of such payment; by

         (2)      the then outstanding principal amount of such Indebtedness.

                                       20
<PAGE>

        "Wholly Owned Restricted Subsidiary" of any Person means a Restricted
Subsidiary of such Person all of the outstanding Capital Stock or other
ownership interests of which (other than directors' qualifying shares) shall at
the time be owned by such Person or by one or more Wholly Owned Restricted
Subsidiaries of such Person or by such Person and one or more Wholly Owned
Restricted Subsidiaries of such Person.

Section 1.02.  Other Definitions.

<TABLE>
<CAPTION>
                                                                                               Defined in
        Term                                                                                     Section
        ----                                                                                     -------
        <S>                                                                                    <C>
        "Affiliate Transaction"............................................................        4.11
        "Asset Sale".......................................................................        4.10
        "Asset Sale Offer".................................................................        3.09
        "Authentication Order".............................................................        2.02
        "Change of Control Offer"..........................................................        4.15
        "Change of Control Payment"........................................................        4.15
        "Change of Control Payment Date"...................................................        4.15
        "Covenant Defeasance"..............................................................        8.03
        "Event of Default".................................................................        6.01
        "Excess Proceeds"..................................................................        4.10
        "incur"............................................................................        4.09
        "Legal Defeasance".................................................................        8.02
        "Offer Amount".....................................................................        3.09
        "Offer Period".....................................................................        3.09
        "Paying Agent".....................................................................        2.03
        "Payment Default"..................................................................        6.01
        "Permitted Debt"...................................................................        4.09
        "Purchase Date"....................................................................        3.09
        "Registrar"........................................................................        2.03
        "Restricted Payments"..............................................................        4.07
</TABLE>

Section 1.03.  Incorporation by Reference of Trust Indenture Act.

        Whenever this Indenture refers to a provision of the TIA, the provision
is incorporated by reference in and made a part of this Indenture.

        The following TIA terms used in this Indenture have the following
meanings:

        "indenture securities" means the Notes;

        "indenture security Holder" means a Holder of a Note;

        "indenture to be qualified" means this Indenture;

        "indenture trustee" or "institutional trustee" means the Trustee; and

        "obligor" on the Notes means the Company and any successor obligor upon
the Notes.

                                       21
<PAGE>

         All other terms used in this Indenture that are defined by the TIA,
defined by the TIA's reference to another statute or defined by SEC rule under
the TIA have the meanings so assigned to them.

Section 1.04.  Rules of Construction.

         Unless the context otherwise requires:

         (a)   a term has the meaning assigned to it;

         (b)   an accounting term not otherwise defined has the meaning assigned
to it in accordance with GAAP;

         (c)   "or" is not exclusive;

         (d)   words in the singular include the plural, and in the plural
include the singular;

         (e)   provisions apply to successive events and transactions; and

         (f)   references to sections of or rules under the Securities Act shall
be deemed to include substitute, replacement or successor sections or rules
adopted by the SEC from time to time.

                                   ARTICLE 2
                                   THE NOTES

Section 2.01.  Form and Dating.

         (a)   General. The Notes and the Trustee's certificate of
authentication shall be substantially in the form of Exhibit A hereto. The Notes
may have notations, legends or endorsements required by law, stock exchange rule
or usage. Each Note shall be dated the date of its authentication. The Notes
shall be in denominations of $1,000 and integral multiples thereof.

         The terms and provisions contained in the Notes shall constitute, and
are hereby expressly made, a part of this Indenture and the Company and the
Trustee, by their execution and delivery of this Indenture, expressly agree to
such terms and provisions and to be bound thereby. However, to the extent any
provision of any Note conflicts with the express provisions of this Indenture,
the provisions of this Indenture shall govern and be controlling.

         (b)   Global Notes. Notes issued in global form shall be substantially
in the form of Exhibit A attached hereto (including the Global Note Legend
thereon and the "Schedule of Exchanges of Interests in the Global Note" attached
thereto). Notes issued in definitive form shall be substantially in the form of
Exhibit A attached hereto (but without the Global Note Legend thereon and
without the "Schedule of Exchanges of Interests in the Global Note" attached
thereto). Each Global Note shall represent such of the outstanding Notes as
shall be specified therein and each shall provide that it shall represent the
aggregate principal amount of outstanding Notes from time to time endorsed
thereon and that the aggregate principal amount of outstanding Notes represented
thereby may from time to time be reduced or increased, as appropriate, to
reflect exchanges and redemptions. Any endorsement of a Global Note to reflect
the amount of any increase or decrease in the aggregate principal amount of
outstanding Notes

                                       22
<PAGE>

represented thereby shall be made by the Trustee or the Custodian, at the
direction of the Trustee, in accordance with instructions given by the Holder
thereof as required by Section 2.06 hereof.

        (c)    Euroclear and Clearstream Procedures Applicable. The provisions
of the "Operating Procedures of the Euroclear System" and "Terms and Conditions
Governing Use of Euroclear" and the "General Terms and Conditions of Clearstream
Bank" and "Customer Handbook" of Clearstream Bank shall be applicable to
transfers of beneficial interests in Global Notes that are held by Participants
through Euroclear or Clearstream Bank.

Section 2.02.  Execution and Authentication.

         Two Officers shall sign the Notes for the Company by manual or
facsimile signature.

         If an Officer whose signature is on a Note no longer holds that office
at the time a Note is authenticated, the Note shall nevertheless be valid.

         A Note shall not be valid until authenticated by the manual signature
of the Trustee. The signature shall be conclusive evidence that the Note has
been authenticated under this Indenture.

         The Trustee shall, upon a written order of the Company signed by two
Officers (an "Authentication Order"), authenticate Notes for original issue up
to the aggregate principal amount stated in paragraph 4 of the Notes. The
aggregate principal amount of Notes outstanding at any time may not exceed such
amount except as provided in Section 2.08 hereof.

         The Trustee may appoint an authenticating agent acceptable to the
Company to authenticate Notes. An authenticating agent may authenticate Notes
whenever the Trustee may do so. Each reference in this Indenture to
authentication by the Trustee includes authentication by such agent. An
authenticating agent has the same rights as an Agent to deal with Holders or an
Affiliate of the Company.

Section 2.03.  Registrar and Paying Agent.

         The Company shall maintain an office or agency where Notes may be
presented for registration of transfer or for exchange ("Registrar") and an
office or agency where Notes may be presented for payment ("Paying Agent"). The
Registrar shall keep a register of the Notes and of their transfer and exchange.
The Company may appoint one or more co-registrars and one or more additional
paying agents. The term "Registrar" includes any co-registrar and the term
"Paying Agent" includes any additional paying agent. The Company may change any
Paying Agent or Registrar without notice to any Holder. The Company shall notify
the Trustee in writing of the name and address of any Agent not a party to this
Indenture. If the Company fails to appoint or maintain another entity as
Registrar or Paying Agent, the Trustee shall act as such. The Company or any of
its Subsidiaries may act as Paying Agent or Registrar.

         The Company initially appoints The Depository Trust Company ("DTC") to
act as Depositary with respect to the Global Notes.

         The Company initially appoints the Trustee to act as the Registrar and
Paying Agent and to act as Custodian with respect to the Global Notes.

                                       23
<PAGE>

Section 2.04.  Paying Agent to Hold Money in Trust.

         The Company shall require each Paying Agent other than the Trustee to
agree in writing that the Paying Agent will hold in trust for the benefit of the
Holders or the Trustee all money held by the Paying Agent for the payment of
principal of, or premium, if any, or interest on the Notes, and will notify the
Trustee of any default by the Company in making any such payment. While any such
default continues, the Trustee may require a Paying Agent to pay all money held
by it to the Trustee. The Company at any time may require a Paying Agent to pay
all money held by it to the Trustee. Upon payment over to the Trustee, the
Paying Agent (if other than the Company or a Subsidiary) shall have no further
liability for the money. If the Company or a Subsidiary acts as Paying Agent, it
shall segregate and hold in a separate trust fund for the benefit of the Holders
all money held by it as Paying Agent. Upon any bankruptcy or reorganization
proceedings relating to the Company, the Trustee shall serve as Paying Agent for
the Notes.

Section 2.05.  Holder Lists.

         The Trustee shall preserve in as current a form as is reasonably
practicable the most recent list available to it of the names and addresses of
all Holders and shall otherwise comply with TIA (S). 312(a). If the Trustee is
not the Registrar, the Company shall furnish to the Trustee at least seven
Business Days before each interest payment date and at such other times as the
Trustee may request in writing, a list in such form and as of such date as the
Trustee may reasonably require of the names and addresses of the Holders of
Notes, and the Company shall otherwise comply with TIA (S). 312(a).

Section 2.06.  Transfer and Exchange.

        (a)    Transfer and Exchange of Global Notes. A Global Note may not be
transferred as a whole except by the Depositary to a nominee of the Depositary,
by a nominee of the Depositary to the Depositary or to another nominee of the
Depositary, or by the Depositary or any such nominee to a successor Depositary
or a nominee of such successor Depositary. All Global Notes will be exchanged by
the Company for Definitive Notes if (i) the Company delivers to the Trustee
notice from the Depositary that it is unwilling or unable to continue to act as
Depositary or that it is no longer a clearing agency registered under the
Exchange Act and, in either case, a successor Depositary is not appointed by the
Company within 120 days after the date of such notice from the Depositary or
(ii) the Company in its sole discretion determines that the Global Notes (in
whole but not in part) should be exchanged for Definitive Notes and delivers a
written notice to such effect to the Trustee. Upon the occurrence of either of
the preceding events in (i) or (ii) above, Definitive Notes shall be issued in
such names as the Depositary shall instruct the Trustee. Global Notes also may
be exchanged or replaced, in whole or in part, as provided in Sections 2.07 and
2.10 hereof. Every Note authenticated and delivered in exchange for, or in lieu
of, a Global Note or any portion thereof, pursuant to this Section 2.06, or
Section 2.07 or 2.10 hereof, shall be authenticated and delivered in the form
of, and shall be, a Global Note. A Global Note may not be exchanged for another
Note other than as provided in this Section 2.06(a); however, beneficial
interests in a Global Note may be transferred and exchanged as provided in
Section 2.06(b), (c) or (f) hereof.

        (b)    Transfer and Exchange of Beneficial Interests in the Global
Notes. The transfer and exchange of beneficial interests in the Global Notes
shall be effected through the Depositary, in accordance with the provisions of
this Indenture and the Applicable Procedures. Beneficial interests in the
Restricted Global Notes shall be subject to restrictions on transfer comparable
to those set forth

                                       24
<PAGE>

herein to the extent required by the Securities Act. Transfers of beneficial
interests in the Global Notes also shall require compliance with either
subparagraph (i) or (ii) below, as applicable, as well as one or more of the
other following subparagraphs, as applicable:

               (i)    Transfer of Beneficial Interests in the Same Global Note.
         Beneficial interests in any Restricted Global Note may be transferred
         to Persons who take delivery thereof in the form of a beneficial
         interest in the same Restricted Global Note in accordance with the
         transfer restrictions set forth in the Private Placement Legend;
         provided, however, that prior to the expiration of the Restricted
         Period, transfers of beneficial interests in the Regulation S Global
         Note may not be made to a U.S. Person or for the account or benefit of
         a U.S. Person (other than an Initial Purchaser). Beneficial interests
         in any Unrestricted Global Note may be transferred to Persons who take
         delivery thereof in the form of a beneficial interest in an
         Unrestricted Global Note. No written orders or instructions shall be
         required to be delivered to the Registrar to effect the transfers
         described in this Section 2.06(b)(i).

               (ii)   All Other Transfers and Exchanges of Beneficial Interests
         in Global Notes. In connection with all transfers and exchanges of
         beneficial interests that are not subject to Section 2.06(b)(i) above,
         the transferor of such beneficial interest must deliver to the
         Registrar either (A) (1) a written order from a Participant or an
         Indirect Participant given to the Depositary in accordance with the
         Applicable Procedures directing the Depositary to credit or cause to be
         credited a beneficial interest in another Global Note in an amount
         equal to the beneficial interest to be transferred or exchanged and (2)
         instructions given in accordance with the Applicable Procedures
         containing information regarding the Participant account to be credited
         with such increase or (B) (1) a written order from a Participant or an
         Indirect Participant given to the Depositary in accordance with the
         Applicable Procedures directing the Depositary to cause to be issued a
         Definitive Note in an amount equal to the beneficial interest to be
         transferred or exchanged and (2) instructions given by the Depositary
         to the Registrar containing information regarding the Person in whose
         name such Definitive Note shall be registered to effect the transfer or
         exchange referred to in (1) above. Upon consummation of an Exchange
         Offer by the Company in accordance with Section 2.06(f) hereof, the
         requirements of this Section 2.06(b)(ii) shall be deemed to have been
         satisfied upon receipt by the Registrar of the instructions contained
         in the Letter of Transmittal delivered by the Holder of such beneficial
         interests in the Restricted Global Notes. Upon satisfaction of all of
         the requirements for transfer or exchange of beneficial interests in
         Global Notes contained in this Indenture and the Notes or otherwise
         applicable under the Securities Act, the Trustee shall adjust the
         principal amount of the relevant Global Note(s) pursuant to Section
         2.06(g) hereof.

               (iii)  Transfer of Beneficial Interests to Another Restricted
         Global Note. A beneficial interest in any Restricted Global Note may be
         transferred to a Person who takes delivery thereof in the form of a
         beneficial interest in another Restricted Global Note if the transfer
         complies with the requirements of Section 2.06(b)(ii) above and the
         Registrar receives the following:

                      (A)   if the transferee will take delivery in the form of
               a beneficial interest in the 144A Global Note, then the
               transferor must deliver a certificate in the form of Exhibit B
               hereto, including the certifications in item (1) thereof;

                                       25
<PAGE>

                      (B)   if the transferee will take delivery in the form of
               a beneficial interest in the Regulation S Global Note, then the
               transferor must deliver a certificate in the form of Exhibit B
               hereto, including the certifications in item (2) thereof; and

                      (C)   if the transferee will take delivery in the form of
               a beneficial interest in the IAI Global Note, then the transferor
               must deliver a certificate in the form of Exhibit B hereto,
               including the certifications and certificates and Opinion of
               Counsel required by item (3) thereof, if applicable.

               (iv)   Transfer and Exchange of Beneficial Interests in a
         Restricted Global Note for Beneficial Interests in the Unrestricted
         Global Note. A beneficial interest in any Restricted Global Note may be
         exchanged by any holder thereof for a beneficial interest in an
         Unrestricted Global Note or transferred to a Person who takes delivery
         thereof in the form of a beneficial interest in an Unrestricted Global
         Note if the exchange or transfer complies with the requirements of
         Section 2.06(b)(ii) above and:

                      (A)   such exchange or transfer is effected pursuant to
               the Exchange Offer in accordance with the Registration Rights
               Agreement and the holder of the beneficial interest to be
               transferred, in the case of an exchange, or the transferee, in
               the case of a transfer, certifies in the applicable Letter of
               Transmittal that it is not (1) a broker-dealer, (2) a Person
               participating in the distribution of the Exchange Notes or (3) a
               Person who is an affiliate (as defined in Rule 144) of the
               Company;

                      (B)   such transfer is effected pursuant to the Shelf
               Registration Statement in accordance with the Registration Rights
               Agreement;

                      (C)   such transfer is effected by a Broker-Dealer
               pursuant to the Exchange Offer Registration Statement in
               accordance with the Registration Rights Agreement; or

                      (D)   the Registrar receives the following:

                                   (1)    if the holder of such beneficial
                            interest in a Restricted Global Note proposes to
                            exchange such beneficial interest for a beneficial
                            interest in an Unrestricted Global Note, a
                            certificate from such holder in the form of Exhibit
                            C hereto, including the certifications in item
                            (1)(a) thereof; or

                                   (2)    if the holder of such beneficial
                            interest in a Restricted Global Note proposes to
                            transfer such beneficial interest to a Person who
                            shall take delivery thereof in the form of a
                            beneficial interest in an Unrestricted Global Note,
                            a certificate from such holder in the form of
                            Exhibit B hereto, including the certifications in
                            item (4) thereof;

               and, in each such case set forth in this subparagraph (D), if the
               Registrar so requests or if the Applicable Procedures so require,
               an Opinion of Counsel in form reasonably acceptable to the
               Registrar to the effect that such exchange or transfer is in
               compliance with the Securities Act and that the restrictions on
               transfer contained herein and in the

                                       26
<PAGE>

               Private Placement Legend are no longer required in order to
               maintain compliance with the Securities Act.

         If any such transfer is effected pursuant to subparagraph (B) or (D)
above at a time when an Unrestricted Global Note has not yet been issued, the
Company shall issue and, upon receipt of an Authentication Order in accordance
with Section 2.02 hereof, the Trustee shall authenticate one or more
Unrestricted Global Notes in an aggregate principal amount equal to the
aggregate principal amount of beneficial interests transferred pursuant to
subparagraph (B) or (D) above.

         Beneficial interests in an Unrestricted Global Note cannot be exchanged
for, or transferred to Persons who take delivery thereof in the form of, a
beneficial interest in a Restricted Global Note.

         (c)   Transfer or Exchange of Beneficial Interests for Definitive
Notes.

               (i)    Beneficial Interests in Restricted Global Notes to
         Restricted Definitive Notes. If any holder of a beneficial interest in
         a Restricted Global Note proposes to exchange such beneficial interest
         for a Restricted Definitive Note or to transfer such beneficial
         interest to a Person who takes delivery thereof in the form of a
         Restricted Definitive Note, then, upon receipt by the Registrar of the
         following documentation:

                      (A)   if the holder of such beneficial interest in a
               Restricted Global Note proposes to exchange such beneficial
               interest for a Restricted Definitive Note, a certificate from
               such holder in the form of Exhibit C hereto, including the
               certifications in item (2)(a) thereof;

                      (B)   if such beneficial interest is being transferred to
               a QIB in accordance with Rule 144A under the Securities Act, a
               certificate to the effect set forth in Exhibit B hereto,
               including the certifications in item (1) thereof;

                      (C)   if such beneficial interest is being transferred to
               a Non-U.S. Person in an offshore transaction in accordance with
               Rule 903 or Rule 904 under the Securities Act, a certificate to
               the effect set forth in Exhibit B hereto, including the
               certifications in item (2) thereof;

                      (D)   if such beneficial interest is being transferred
               pursuant to an exemption from the registration requirements of
               the Securities Act in accordance with Rule 144 under the
               Securities Act, a certificate to the effect set forth in Exhibit
               B hereto, including the certifications in item (3)(a) thereof;

                      (E)   if such beneficial interest is being transferred to
               an Institutional Accredited Investor in reliance on an exemption
               from the registration requirements of the Securities Act other
               than those listed in subparagraphs (B) through (D) above, a
               certificate to the effect set forth in Exhibit B hereto,
               including the certifications, certificates and Opinion of Counsel
               required by item (3) thereof, if applicable;

                                       27
<PAGE>

                      (F)   if such beneficial interest is being transferred to
               the Company or any of its Subsidiaries, a certificate to the
               effect set forth in Exhibit B hereto, including the
               certifications in item (3)(b) thereof; or

                      (G)   if such beneficial interest is being transferred
               pursuant to an effective registration statement under the
               Securities Act, a certificate to the effect set forth in Exhibit
               B hereto, including the certifications in item (3)(c) thereof,

               the Trustee shall cause the aggregate principal amount of the
               applicable Global Note to be reduced accordingly pursuant to
               Section 2.06(h) hereof, and the Company shall execute and the
               Trustee shall authenticate and deliver to the Person designated
               in the instructions a Definitive Note in the appropriate
               principal amount. Any Definitive Note issued in exchange for a
               beneficial interest in a Restricted Global Note pursuant to this
               Section 2.06(c) shall be registered in such name or names and in
               such authorized denomination or denominations as the holder of
               such beneficial interest shall instruct the Registrar through
               instructions from the Depositary and the Participant or Indirect
               Participant. The Trustee shall deliver such Definitive Notes to
               the Persons in whose names such Notes are so registered. Any
               Definitive Note issued in exchange for a beneficial interest in a
               Restricted Global Note pursuant to this Section 2.06(c)(i) shall
               bear the Private Placement Legend and shall be subject to all
               restrictions on transfer contained therein.

               (ii)   Beneficial Interests in Restricted Global Notes to
         Unrestricted Definitive Notes. A holder of a beneficial interest in a
         Restricted Global Note may exchange such beneficial interest for an
         Unrestricted Definitive Note or may transfer such beneficial interest
         to a Person who takes delivery thereof in the form of an Unrestricted
         Definitive Note only if:

                      (A)   such exchange or transfer is effected pursuant to
               the Exchange Offer in accordance with the Registration Rights
               Agreement and the holder of such beneficial interest, in the case
               of an exchange, or the transferee, in the case of a transfer,
               certifies in the applicable Letter of Transmittal that it is not
               (1) a broker-dealer, (2) a Person participating in the
               distribution of the Exchange Notes or (3) a Person who is an
               affiliate (as defined in Rule 144) of the Company;

                      (B)   such transfer is effected pursuant to the Shelf
               Registration Statement in accordance with the Registration Rights
               Agreement;

                      (C)   such transfer is effected by a Broker-Dealer
               pursuant to the Exchange Offer Registration Statement in
               accordance with the Registration Rights Agreement; or

                      (D)   the Registrar receives the following:

                                   (1)    if the holder of such beneficial
                            interest in a Restricted Global Note proposes to
                            exchange such beneficial interest for a Definitive
                            Note that does not bear the Private Placement
                            Legend, a certificate from such holder in the form
                            of Exhibit C hereto, including the certifications in
                            item (1)(b) thereof; or

                                       28
<PAGE>

                                   (2)    if the holder of such beneficial
                            interest in a Restricted Global Note proposes to
                            transfer such beneficial interest to a Person who
                            shall take delivery thereof in the form of a
                            Definitive Note that does not bear the Private
                            Placement Legend, a certificate from such holder in
                            the form of Exhibit B hereto, including the
                            certifications in item (4) thereof;

                            and, in each such case set forth in this
                      subparagraph (D), if the Registrar so requests or if the
                      Applicable Procedures so require, an Opinion of Counsel in
                      form reasonably acceptable to the Registrar to the effect
                      that such exchange or transfer is in compliance with the
                      Securities Act and that the restrictions on transfer
                      contained herein and in the Private Placement Legend are
                      no longer required in order to maintain compliance with
                      the Securities Act.

               (iii)  Beneficial Interests in Unrestricted Global Notes to
         Unrestricted Definitive Notes. If any holder of a beneficial interest
         in an Unrestricted Global Note proposes to exchange such beneficial
         interest for a Definitive Note or to transfer such beneficial interest
         to a Person who takes delivery thereof in the form of a Definitive
         Note, then, upon satisfaction of the conditions set forth in Section
         2.06(b)(ii) hereof, the Trustee shall cause the aggregate principal
         amount of the applicable Global Note to be reduced accordingly pursuant
         to Section 2.06(h) hereof, and the Company shall execute and the
         Trustee shall authenticate and deliver to the Person designated in the
         instructions a Definitive Note in the appropriate principal amount. Any
         Definitive Note issued in exchange for a beneficial interest pursuant
         to this Section 2.06(c)(iii) shall be registered in such name or names
         and in such authorized denomination or denominations as the holder of
         such beneficial interest shall instruct the Registrar through
         instructions from the Depositary and the Participant or Indirect
         Participant. The Trustee shall deliver such Definitive Notes to the
         Persons in whose names such Notes are so registered. Any Definitive
         Note issued in exchange for a beneficial interest pursuant to this
         Section 2.06(c)(iii) shall not bear the Private Placement Legend.

         (d)   Transfer and Exchange of Definitive Notes for Beneficial
Interests in Global Notes.

               (i)    Restricted Definitive Notes to Beneficial Interests in
         Restricted Global Notes. If any Holder of a Restricted Definitive Note
         proposes to exchange such Note for a beneficial interest in a
         Restricted Global Note or to transfer such Restricted Definitive Notes
         to a Person who takes delivery thereof in the form of a beneficial
         interest in a Restricted Global Note, then, upon receipt by the
         Registrar of the following documentation:

                      (A)   if the Holder of such Restricted Definitive Note
               proposes to exchange such Note for a beneficial interest in a
               Restricted Global Note, a certificate from such Holder in the
               form of Exhibit C hereto, including the certifications in item
               (2)(b) thereof;

                      (B)   if such Restricted Definitive Note is being
               transferred to a QIB in accordance with Rule 144A under the
               Securities Act, a certificate to the effect set forth in Exhibit
               B hereto, including the certifications in item (1) thereof;

                      (C)   if such Restricted Definitive Note is being
               transferred to a Non-U.S. Person in an offshore transaction in
               accordance with Rule 903 or Rule 904 under the

                                       29
<PAGE>

               Securities Act, a certificate to the effect set forth in Exhibit
               B hereto, including the certifications in item (2) thereof;

                      (D)   if such Restricted Definitive Note is being
               transferred pursuant to an exemption from the registration
               requirements of the Securities Act in accordance with Rule 144
               under the Securities Act, a certificate to the effect set forth
               in Exhibit B hereto, including the certifications in item (3)(a)
               thereof;

                      (E)   if such Restricted Definitive Note is being
               transferred to an Institutional Accredited Investor in reliance
               on an exemption from the registration requirements of the
               Securities Act other than those listed in subparagraphs (B)
               through (D) above, a certificate to the effect set forth in
               Exhibit B hereto, including the certifications, certificates and
               Opinion of Counsel required by item (3) thereof, if applicable;

                      (F)   if such Restricted Definitive Note is being
               transferred to the Company or any of its Subsidiaries, a
               certificate to the effect set forth in Exhibit B hereto,
               including the certifications in item (3)(b) thereof; or

                      (G)   if such Restricted Definitive Note is being
               transferred pursuant to an effective registration statement under
               the Securities Act, a certificate to the effect set forth in
               Exhibit B hereto, including the certifications in item (3)(c)
               thereof,

               the Trustee shall cancel the Restricted Definitive Note, increase
               or cause to be increased the aggregate principal amount of, in
               the case of clause (A) above, the appropriate Restricted Global
               Note, in the case of clause (B) above, the 144A Global Note, in
               the case of clause (C) above, the Regulation S Global Note, and
               in all other cases, the IAI Global Note.

               (ii)   Restricted Definitive Notes to Beneficial Interests in
         Unrestricted Global Notes. A Holder of a Restricted Definitive Note may
         exchange such Note for a beneficial interest in an Unrestricted Global
         Note or transfer such Restricted Definitive Note to a Person who takes
         delivery thereof in the form of a beneficial interest in an
         Unrestricted Global Note only if:

                      (A)   such exchange or transfer is effected pursuant to
               the Exchange Offer in accordance with the Registration Rights
               Agreement and the Holder, in the case of an exchange, or the
               transferee, in the case of a transfer, certifies in the
               applicable Letter of Transmittal that it is not (1) a broker-
               dealer, (2) a Person participating in the distribution of the
               Exchange Notes or (3) a Person who is an affiliate (as defined in
               Rule 144) of the Company;

                       (B)  such transfer is effected pursuant to the Shelf
               Registration Statement in accordance with the Registration Rights
               Agreement;

                       (C)  such transfer is effected by a Broker-Dealer
               pursuant to the Exchange Offer Registration Statement in
               accordance with the Registration Rights Agreement; or

                       (D)  the Registrar receives the following:

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<PAGE>

                         (1)   if the Holder of such Definitive Notes proposes
                    to exchange such Notes for a beneficial interest in the
                    Unrestricted Global Note, a certificate from such Holder in
                    the form of Exhibit C hereto, including the certifications
                    in item (1)(c) thereof; or

                         (2)   if the Holder of such Definitive Notes proposes
                    to transfer such Notes to a Person who shall take delivery
                    thereof in the form of a beneficial interest in the
                    Unrestricted Global Note, a certificate from such Holder in
                    the form of Exhibit B hereto, including the certifications
                    in item (4) thereof;

          and, in each such case set forth in this subparagraph (D), if the
          Registrar so requests or if the Applicable Procedures so require, an
          Opinion of Counsel in form reasonably acceptable to the Registrar to
          the effect that such exchange or transfer is in compliance with the
          Securities Act and that the restrictions on transfer contained herein
          and in the Private Placement Legend are no longer required in order to
          maintain compliance with the Securities Act.

     Upon satisfaction of the conditions of any of the subparagraphs in this
Section 2.06(d)(ii), the Trustee shall cancel the Definitive Notes and increase
or cause to be increased the aggregate principal amount of the Unrestricted
Global Note.

          (iii)  Unrestricted Definitive Notes to Beneficial Interests in
     Unrestricted Global Notes. A Holder of an Unrestricted Definitive Note may
     exchange such Note for a beneficial interest in an Unrestricted Global Note
     or transfer such Definitive Notes to a Person who takes delivery thereof in
     the form of a beneficial interest in an Unrestricted Global Note at any
     time. Upon receipt of a request for such an exchange or transfer, the
     Trustee shall cancel the applicable Unrestricted Definitive Note and
     increase or cause to be increased the aggregate principal amount of one of
     the Unrestricted Global Notes.

                 If any such exchange or transfer from a Definitive Note to a
          beneficial interest is effected pursuant to subparagraphs (ii)(B),
          (ii)(D) or (iii) above at a time when an Unrestricted Global Note has
          not yet been issued, the Company shall issue and, upon receipt of an
          Authentication Order in accordance with Section 2.02 hereof, the
          Trustee shall authenticate one or more Unrestricted Global Notes in an
          aggregate principal amount equal to the principal amount of Definitive
          Notes so transferred.

     (e)  Transfer and Exchange of Definitive Notes for Definitive Notes. Upon
request by a Holder of Definitive Notes and such Holder's compliance with the
provisions of this Section 2.06(e), the Registrar shall register the transfer or
exchange of Definitive Notes. Prior to such registration of transfer or
exchange, the requesting Holder shall present or surrender to the Registrar the
Definitive Notes duly endorsed or accompanied by a written instruction of
transfer in form satisfactory to the Registrar duly executed by such Holder or
by its attorney, duly authorized in writing. In addition, the requesting Holder
shall provide any additional certifications, documents and information, as
applicable, required pursuant to the following provisions of this Section
2.06(e).

                                       31
<PAGE>

     (i)  Restricted Definitive Notes to Restricted Definitive Notes. Any
Restricted Definitive Note may be transferred to and registered in the name of
Persons who take delivery thereof in the form of a Restricted Definitive Note if
the Registrar receives the following:

          (A)  if the transfer will be made pursuant to Rule 144A under the
     Securities Act, then the transferor must deliver a certificate in the form
     of Exhibit B hereto, including the certifications in item (1) thereof;

          (B)  if the transfer will be made pursuant to Rule 903 or Rule 904,
     then the transferor must deliver a certificate in the form of Exhibit B
     hereto, including the certifications in item (2) thereof; and

          (C)  if the transfer will be made pursuant to any other exemption from
     the registration requirements of the Securities Act, then the transferor
     must deliver a certificate in the form of Exhibit B hereto, including the
     certifications, certificates and Opinion of Counsel required by item (3)
     thereof, if applicable.

     (ii) Restricted Definitive Notes to Unrestricted Definitive Notes. Any
Restricted Definitive Note may be exchanged by the Holder thereof for an
Unrestricted Definitive Note or transferred to a Person or Persons who take
delivery thereof in the form of an Unrestricted Definitive Note if:

          (A)  such exchange or transfer is effected pursuant to the Exchange
     Offer in accordance with the Registration Rights Agreement and the Holder,
     in the case of an exchange, or the transferee, in the case of a transfer,
     certifies in the applicable Letter of Transmittal that it is not (1) a
     broker-dealer, (2) a Person participating in the distribution of the
     Exchange Notes or (3) a Person who is an affiliate (as defined in Rule 144)
     of the Company;

          (B)  any such transfer is effected pursuant to the Shelf Registration
     Statement in accordance with the Registration Rights Agreement;

          (C)  any such transfer is effected by a Broker-Dealer pursuant to the
     Exchange Offer Registration Statement in accordance with the Registration
     Rights Agreement; or

          (D)  the Registrar receives the following:

                    (1)  if the Holder of such Restricted Definitive Notes
               proposes to exchange such Notes for an Unrestricted Definitive
               Note, a certificate from such Holder in the form of Exhibit C
               hereto, including the certifications in item (1)(d) thereof; or

                    (2)  if the Holder of such Restricted Definitive Notes
               proposes to transfer such Notes to a Person who shall take
               delivery thereof in the form of an Unrestricted Definitive Note,
               a certificate from such Holder in the form of Exhibit B hereto,
               including the certifications in item (4) thereof;

                                       32
<PAGE>

          and, in each such case set forth in this subparagraph (D), if the
          Registrar so requests, an Opinion of Counsel in form reasonably
          acceptable to the Company to the effect that such exchange or transfer
          is in compliance with the Securities Act and that the restrictions on
          transfer contained herein and in the Private Placement Legend are no
          longer required in order to maintain compliance with the Securities
          Act.

          (iii)  Unrestricted Definitive Notes to Unrestricted Definitive Notes.
     A Holder of Unrestricted Definitive Notes may transfer such Notes to a
     Person who takes delivery thereof in the form of an Unrestricted Definitive
     Note. Upon receipt of a request to register such a transfer, the Registrar
     shall register the Unrestricted Definitive Notes pursuant to the
     instructions from the Holder thereof.

     (f)  Exchange Offer. Upon the occurrence of the Exchange Offer in
accordance with the Registration Rights Agreement, the Company shall issue and,
upon receipt of an Authentication Order in accordance with Section 2.02, the
Trustee shall authenticate (i) one or more Unrestricted Global Notes in an
aggregate principal amount equal to the principal amount of the beneficial
interests in the Restricted Global Notes tendered for acceptance by Persons that
certify in the applicable Letters of Transmittal that (x) they are not broker-
dealers, (y) they are not participating in a distribution of the Exchange Notes
and (z) they are not affiliates (as defined in Rule 144) of the Company, and
accepted for exchange in the Exchange Offer and (ii) Definitive Notes in an
aggregate principal amount equal to the principal amount of the Restricted
Definitive Notes accepted for exchange in the Exchange Offer. Concurrently with
the issuance of such Notes, the Trustee shall cause the aggregate principal
amount of the applicable Restricted Global Notes to be reduced accordingly, and
the Company shall execute and the Trustee shall authenticate and deliver to the
Persons designated by the Holders of Definitive Notes so accepted Definitive
Notes in the appropriate principal amount.

     (g)  Legends. The following legends shall appear on the face of all Global
Notes and Definitive Notes issued under this Indenture unless specifically
stated otherwise in the applicable provisions of this Indenture.

          (i)    Private Placement Legend.

                 (A)   Except as permitted by subparagraph (B) below, each
          Global Note and each Definitive Note (and all Notes issued in exchange
          therefor or substitution thereof) shall bear the legend in
          substantially the following form:

"THE NOTES EVIDENCED HEREBY HAVE NOT BEEN REGISTERED UNDER THE UNITED STATES
SECURITIES ACT OF 1933 (THE "SECURITIES ACT") AND MAY NOT BE OFFERED, SOLD,
PLEDGED OR OTHERWISE TRANSFERRED EXCEPT (A)(1) TO A PERSON WHO THE SELLER
REASONABLY BELIEVES IS A QUALIFIED INSTITUTIONAL BUYER WITHIN THE MEANING OF
RULE 144A UNDER THE SECURITIES ACT PURCHASING FOR ITS OWN ACCOUNT FOR THE
ACCOUNT OF A QUALIFIED INSTITUTIONAL BUYER IN A TRANSACTION MEETING THE
REQUIREMENTS OF RULE 144A, (2) IN AN OFFSHORE TRANSACTION COMPLYING WITH RULE
903 OR RULE 904 OF REGULATION S UNDER THE SECURITIES ACT, (3) TO AN
INSTITUTIONAL ACCREDITED INVESTOR IN A TRANSACTION

                                       33
<PAGE>

EXEMPT FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT, (4) PURSUANT TO
AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT PROVIDED BY RULE 144
THEREUNDER (IF AVAILABLE) OR (5) PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT
UNDER THE SECURITIES ACT AND (B) IN ACCORDANCE WITH ALL APPLICABLE SECURITIES
LAW OF THE STATES OF THE UNITED STATES."

                (B)   Notwithstanding the foregoing, any Global Note or
          Definitive Note issued pursuant to subparagraphs (b)(iv), (c)(ii),
          (c)(iii), (d)(ii), (d)(iii), (e)(ii), (e)(iii) or (f) to this Section
          2.06 (and all Notes issued in exchange therefor or substitution
          thereof) shall not bear the Private Placement Legend.

          (ii)  Global Note Legend. Each Global Note shall bear a legend in
     substantially the following form:

"THIS GLOBAL NOTE IS HELD BY THE DEPOSITARY (AS DEFINED IN THE INDENTURE
GOVERNING THIS NOTE) OR ITS NOMINEE IN CUSTODY FOR THE BENEFIT OF THE BENEFICIAL
OWNERS HEREOF, AND IS NOT TRANSFERABLE TO ANY PERSON UNDER ANY CIRCUMSTANCES
EXCEPT THAT (I) THE TRUSTEE MAY MAKE SUCH NOTATIONS HEREON AS MAY BE REQUIRED
PURSUANT TO SECTION 2.06 OF THE INDENTURE, (II) THIS GLOBAL NOTE MAY BE
EXCHANGED IN WHOLE BUT NOT IN PART PURSUANT TO SECTION 2.06(a) OF THE INDENTURE,
(III) THIS GLOBAL NOTE MAY BE DELIVERED TO THE TRUSTEE FOR CANCELLATION PURSUANT
TO SECTION 2.11 OF THE INDENTURE AND (IV) THIS GLOBAL NOTE MAY BE TRANSFERRED TO
A SUCCESSOR DEPOSITARY WITH THE PRIOR WRITTEN CONSENT OF CROWN CASTLE
INTERNATIONAL CORP."

     (h)  Cancellation and/or Adjustment of Global Notes. At such time as all
beneficial interests in a particular Global Note have been exchanged for
Definitive Notes or a particular Global Note has been redeemed, repurchased or
canceled in whole and not in part, each such Global Note shall be returned to or
retained and canceled by the Trustee in accordance with Section 2.11 hereof. At
any time prior to such cancellation, if any beneficial interest in a Global Note
is exchanged for or transferred to a Person who will take delivery thereof in
the form of a beneficial interest in another Global Note or for Definitive
Notes, the principal amount of Notes represented by such Global Note shall be
reduced accordingly and an endorsement shall be made on such Global Note by the
Trustee or by the Depositary at the direction of the Trustee to reflect such
reduction; and if the beneficial interest is being exchanged for or transferred
to a Person who will take delivery thereof in the form of a beneficial interest
in another Global Note, such other Global Note shall be increased accordingly
and an endorsement shall be made on such Global Note by the Trustee or by the
Depositary at the direction of the Trustee to reflect such increase.

     (i)  General Provisions Relating to Transfers and Exchanges.

          (i)    To permit registrations of transfers and exchanges, the Company
     shall execute and the Trustee shall authenticate Global Notes and
     Definitive Notes upon the Company's order or at the Registrar's request.

                                       34
<PAGE>

          (ii)   No service charge shall be made to a holder of a beneficial
     interest in a Global Note or to a Holder of a Definitive Note for any
     registration of transfer or exchange, but the Company may require payment
     of a sum sufficient to cover any transfer tax or similar governmental
     charge payable in connection therewith (other than any such transfer taxes
     or similar governmental charge payable upon exchange or transfer pursuant
     to Sections 2.10, 3.06, 3.09, 4.10, 4.15 and 9.05 hereof).

          (iii)  The Registrar shall not be required to register the transfer of
     or exchange any Note selected for redemption in whole or in part, except
     the unredeemed portion of any Note being redeemed in part.

          (iv)   All Global Notes and Definitive Notes issued upon any
     registration of transfer or exchange of Global Notes or Definitive Notes
     shall be the valid obligations of the Company, evidencing the same debt,
     and entitled to the same benefits under this Indenture, as the Global Notes
     or Definitive Notes surrendered upon such registration of transfer or
     exchange.

          (v)    The Company shall not be required (A) to issue, to register the
     transfer of or to exchange any Notes during a period beginning at the
     opening of business 15 days before the day of any selection of Notes for
     redemption under Section 3.02 hereof and ending at the close of business on
     the day of selection, (B) to register the transfer of or to exchange any
     Note so selected for redemption in whole or in part, except the unredeemed
     portion of any Note being redeemed in part or (C) to register the transfer
     of or to exchange a Note between a record date and the next succeeding
     Interest Payment Date.

          (vi)   Prior to due presentment for the registration of a transfer of
     any Note, the Trustee, any Agent and the Company may deem and treat the
     Person in whose name any Note is registered as the absolute owner of such
     Note for the purpose of receiving payment of principal of and interest on
     such Notes and for all other purposes, and none of the Trustee, any Agent
     or the Company shall be affected by notice to the contrary.

          (vii)  The Trustee shall authenticate Global Notes and Definitive
     Notes in accordance with the provisions of Section 2.02 hereof.

          (viii) All certifications, certificates and Opinions of Counsel
     required to be submitted to the Registrar pursuant to this Section 2.06 to
     effect a registration of transfer or exchange may be submitted by
     facsimile.

Section 2.07.  Replacement Notes.

     If any mutilated Note is surrendered to the Trustee or the Company and the
Trustee receives evidence to its satisfaction of the destruction, loss or theft
of any Note, the Company shall issue and the Trustee, upon receipt of an
Authentication Order, shall authenticate a replacement Note if the Trustee's
requirements are met. If required by the Trustee or the Company, an indemnity
bond must be supplied by the Holder that is sufficient in the judgment of the
Trustee and the Company to protect the Company, the Trustee, any Agent and any
authenticating agent from any loss that any of them may suffer if a Note is
replaced. The Company may charge for its expenses in replacing a Note.

                                       35
<PAGE>

     Every replacement Note is an additional obligation of the Company and shall
be entitled to all of the benefits of this Indenture equally and proportionately
with all other Notes duly issued hereunder.

Section 2.08.  Outstanding Notes.

     The Notes outstanding at any time are all the Notes authenticated by the
Trustee except for those canceled by it, those delivered to it for cancellation,
those reductions in the interest in a Global Note effected by the Trustee in
accordance with the provisions hereof, and those described in this Section as
not outstanding. Except as set forth in Section 2.09 hereof, a Note does not
cease to be outstanding because the Company or an Affiliate of the Company holds
the Note; however, Notes held by the Company or a Subsidiary of the Company
shall not be deemed to be outstanding for purposes of Section 3.07(b) hereof.

     If a Note is replaced pursuant to Section 2.07 hereof, it ceases to be
outstanding unless the Trustee receives proof satisfactory to it that the
replaced Note is held by a bona fide purchaser.

     If the principal amount of any Note is considered paid under Section 4.01
hereof, it ceases to be outstanding and interest on it ceases to accrue.

     If the Paying Agent (other than the Company, a Subsidiary or an Affiliate
of any thereof) holds, on a redemption date or maturity date, money sufficient
to pay Notes payable on that date, then on and after that date such Notes shall
be deemed to be no longer outstanding and shall cease to accrue interest.

Section 2.09.  Treasury Notes.

     In determining whether the Holders of the required principal amount of
Notes have concurred in any direction, waiver or consent, Notes owned by the
Company, or by any Person directly or indirectly controlling or controlled by or
under direct or indirect common control with the Company, shall be considered as
though not outstanding, except that for the purposes of determining whether the
Trustee shall be protected in relying on any such direction, waiver or consent,
only Notes that the Trustee knows are so owned shall be so disregarded.

Section 2.10.  Temporary Notes.

     Until certificates representing Notes are ready for delivery, the Company
may prepare and the Trustee, upon receipt of an Authentication Order, shall
authenticate temporary Notes. Temporary Notes shall be substantially in the form
of certificated Notes but may have variations that the Company considers
appropriate for temporary Notes and as shall be reasonably acceptable to the
Trustee. Without unreasonable delay, the Company shall prepare and the Trustee
shall authenticate definitive Notes in exchange for temporary Notes.

     Holders of temporary Notes shall be entitled to all of the benefits of this
Indenture.

Section 2.11.  Cancellation.

     The Company at any time may deliver Notes to the Trustee for cancellation.
The Registrar and Paying Agent shall forward to the Trustee any Notes
surrendered to them for registration of transfer, exchange or payment. The
Trustee and no one else shall cancel all Notes surrendered for registration of

                                       36
<PAGE>

transfer, exchange, payment, replacement or cancellation and shall destroy
canceled Notes (subject to the record retention requirement of the Exchange
Act). Certification of the destruction of all canceled Notes shall be delivered
to the Company. The Company may not issue new Notes to replace Notes that it has
paid or that have been delivered to the Trustee for cancellation.

Section 2.12.  Defaulted Interest.

     If the Company defaults in a payment of interest on the Notes, it shall pay
the defaulted interest in any lawful manner, plus, to the extent lawful,
interest payable on the defaulted interest, to the Persons who are Holders on a
subsequent special record date, in each case at the rate provided in the Notes
and in Section 4.01 hereof. The Company shall notify the Trustee in writing of
the amount of defaulted interest proposed to be paid on each Note and the date
of the proposed payment. The Company shall fix or cause to be fixed each such
special record date and payment date, provided that no such special record date
shall be less than 10 days prior to the related payment date for such defaulted
interest. At least 15 days before the special record date, the Company (or, upon
the written request of the Company, the Trustee in the name and at the expense
of the Company) shall mail or cause to be mailed to Holders a notice that states
the special record date, the related payment date and the amount of such
interest to be paid.

                                   ARTICLE 3
                           REDEMPTION AND PREPAYMENT

Section 3.01.  Notices to Trustee.

     If the Company elects to redeem Notes pursuant to the optional redemption
provisions of Section 3.07 hereof, it shall furnish to the Trustee, at least 30
days but not more than 60 days before a redemption date, an Officers'
Certificate setting forth (1) the clause of this Indenture pursuant to which the
redemption shall occur, (2) the redemption date, (3) the principal amount of
Notes to be redeemed and (4) the redemption price (expressed as a percentage of
the principal amount).

Section 3.02.  Selection of Notes to Be Redeemed.

     If less than all of the Notes are to be redeemed or purchased in an offer
to purchase at any time, the Trustee shall select the Notes to be redeemed as
follows:

     (1)  if the Notes are listed on any national securities exchange, in
compliance with the requirements of the principal national securities exchange,
if any, on which the Notes are listed; or

     (2)  if the Notes are not listed on any national securities exchange, on a
pro rata basis, by lot or by such other method as the Trustee shall deem fair
and appropriate.

     No Notes of $1,000 of principal amount or less will be redeemed in part.
Except as provided in the preceding sentence, provisions of this Indenture that
apply to Notes called for redemption also apply to portions of Notes called for
redemption. Notices of redemption will be mailed by first class mail at least 30
but not more than 60 days before the redemption date to each Holder of Notes to
be redeemed at its registered address. Notices of redemption may not be
conditional.

     If any Note is to be redeemed in part only, the notice of redemption that
relates to such Note shall state the portion of the principal amount of that
Note to be redeemed. A new Note in principal

                                       37
<PAGE>

amount equal to the unredeemed portion of the original Note presented for
redemption will be issued in the name of the Holder thereof upon cancellation of
the original Note. Notes called for redemption become due on the date fixed for
redemption. On and after the redemption date, interest ceases to accrue on Notes
or portions of them called for redemption.

Section 3.03.  Notice of Redemption.

     Subject to the provisions of Section 3.09 hereof, at least 30 days but not
more than 60 days before a redemption date, the Company shall mail or cause to
be mailed, by first class mail, a notice of redemption to each Holder whose
Notes are to be redeemed at its registered address.

     The notice shall identify the Notes to be redeemed and shall state:

     (1)  the redemption date;

     (2)  the redemption price;

     (3)  if any Note is being redeemed in part, the portion of the principal
amount of such Note to be redeemed and that, after the redemption date upon
surrender of such Note, a new Note or Notes in principal amount equal to the
unredeemed portion shall be issued upon cancellation of the original Note;

     (4)  the name and address of the Paying Agent;

     (5)  that Notes called for redemption must be surrendered to the Paying
Agent to collect the redemption price;

     (6)  that, unless the Company defaults in making such redemption payment,
interest on Notes called for redemption ceases to accrue on and after the
redemption date;

     (7)  the paragraph of the Notes and/or Section of this Indenture pursuant
to which the Notes called for redemption are being redeemed; and

     (8)  that no representation is made as to the correctness or accuracy of
the CUSIP number, if any, listed in such notice or printed on the Notes.

     At the Company's request, the Trustee shall give the notice of redemption
in the Company's name and at its expense; provided, however, that the Company
shall have delivered to the Trustee, at least 45 days prior to the redemption
date, an Officers' Certificate requesting that the Trustee give such notice and
setting forth the information to be stated in such notice as provided in the
preceding paragraph.

Section 3.04.  Effect of Notice of Redemption.

     Once notice of redemption is mailed in accordance with Section 3.03 hereof,
Notes called for redemption become irrevocably due and payable on the redemption
date at the redemption price. A notice of redemption may not be conditional.

Section 3.05.  Deposit of Redemption Price.

                                       38
<PAGE>

     One Business Day prior to the redemption date, the Company shall deposit
with the Trustee or with the Paying Agent money sufficient to pay the redemption
price of and accrued interest on all Notes, if any, to be redeemed on that date.
The Trustee or the Paying Agent shall promptly return to the Company any money
deposited with the Trustee or the Paying Agent by the Company in excess of the
amounts necessary to pay the redemption price of, and accrued interest, if any,
on all Notes to be redeemed.

     If the Company complies with the provisions of the preceding paragraph, on
and after the redemption date, interest shall cease to accrue on the Notes or
the portions of the Notes called for redemption. If a Note is redeemed on or
after an interest record date but on or prior to the related interest payment
date, then any accrued and unpaid interest shall be paid to the Person in whose
name such Note was registered at the close of business on such record date. If
any Note called for redemption shall not be so paid upon surrender for
redemption because of the failure of the Company to comply with the preceding
paragraph, interest shall be paid on the unpaid principal, from the redemption
date until such principal is paid, and, to the extent lawful, on any interest
not paid on such unpaid principal, in each case at the rate provided in the
Notes and in Section 4.01 hereof.

Section 3.06.  Notes Redeemed in Part.

     Upon surrender of a Note that is redeemed in part, the Company shall issue
and, upon the Company's written request, the Trustee shall authenticate for the
Holder at the expense of the Company a new Note equal in principal amount to the
unredeemed portion of the Note surrendered.

Section 3.07.  Optional Redemption.

     (a)  Except as provided in clause (b) of this Section 3.07, the Notes will
not be redeemable at the Company's option prior to August 1, 2006. On or after
August 1, 2006, the Company may redeem all or a part of the Notes upon not less
than 30 nor more than 60 days' notice, at the redemption prices (expressed as
percentages of principal amount) set forth below plus accrued and unpaid
interest, if any, on the Notes redeemed to the applicable redemption date
(subject to the right of Holders of record on the relevant record date to
receive interest due on the relevant interest payment date), if redeemed during
the twelve-month period beginning on August 1 of the years indicated below:

     Year                                                           Percentage
     ----                                                           ----------
     2006.......................................................     104.688%
     2007.......................................................     103.125%
     2008.......................................................     101.563%
     2009 and thereafter........................................     100.000%

     (b)  Notwithstanding the provisions of clause (a) of this Section 3.07, at
any time during the period after the date of the original issuance of the Notes
until August 1, 2004, the Company may on any one or more occasions redeem up to
35% of the aggregate principal amount of the Notes originally issued at a
redemption price equal to 109.375% of the aggregate principal amount of the
Notes to be redeemed on the redemption date with the net cash proceeds of one or
more Public Equity Offerings and/or Strategic Equity Investments provided that:

                                       39
<PAGE>

          (1)  at least 65% of the aggregate principal amount of the Notes
     originally issued remains outstanding immediately after the occurrence of
     such redemption (excluding Notes held by the Company or any of its
     Subsidiaries); and

          (2)  the redemption occurs within 60 days of the date of the closing
     of such Public Equity Offering or Strategic Equity Investment.

     (c)  Any redemption pursuant to this Section 3.07 shall be made pursuant to
the provisions of Section 3.01 through 3.06 hereof.

Section 3.08.  Mandatory Redemption.

     The Company shall not be required to make mandatory redemption or sinking
fund payments with respect to the Notes.

Section 3.09.  Offer to Purchase by Application of Excess Proceeds.

     In the event that, pursuant to Section 4.10 hereof, the Company shall be
required to commence an offer to all Holders to purchase Notes (an "Asset Sale
Offer"), it shall follow the procedures specified below.

     The Asset Sale Offer shall remain open for a period of 20 Business Days
following its commencement and no longer, except to the extent that a longer
period is required by applicable law (the "Offer Period"). No later than five
Business Days after the termination of the Offer Period (the "Purchase Date"),
the Company shall purchase the aggregate principal amount (or accreted value, as
applicable) of Notes and other senior Indebtedness of the Company required to be
purchased pursuant to Section 4.10 hereof (on a pro rata basis if Notes and
other senior Indebtedness of the Company tendered are in excess of the Excess
Proceeds) (which maximum amount shall be the "Offer Amount") or, if less than
the Offer Amount has been tendered, all Notes and other senior Indebtedness
tendered in response to the Asset Sale Offer. Payment for any Notes so purchased
shall be made in the same manner as interest payments are made.

     If the Purchase Date is on or after an interest record date and on or
before the related interest payment date, any accrued and unpaid interest shall
be paid to the Person in whose name a Note is registered at the close of
business on such record date, and no additional interest shall be payable to
Holders who tender Notes pursuant to the Asset Sale Offer.

     Upon the commencement of an Asset Sale Offer, the Company shall send, by
first class mail, a notice to the Trustee and each of the Holders, with a copy
to the Trustee. The notice shall contain all instructions and materials
necessary to enable such Holders to tender Notes pursuant to the Asset Sale
Offer. The Asset Sale Offer shall be made to all Holders. The notice, which
shall govern the terms of the Asset Sale Offer, shall state:

     (a)  that the Asset Sale Offer is being made pursuant to this Section 3.09
and Section 4.10 hereof and the length of time the Asset Sale Offer shall remain
open;

     (b)  the Offer Amount, the purchase price and the Purchase Date;

                                       40
<PAGE>

     (c)  that any Note not tendered or accepted for payment shall continue to
accrue interest;

     (d)  that, unless the Company defaults in making such payment, any Note
accepted for payment pursuant to the Asset Sale Offer shall cease to accrue
interest after the Purchase Date;

     (e)  that Holders electing to have a Note purchased pursuant to an Asset
Sale Offer may elect to have Notes purchased in integral multiples of $1,000
only;

     (f)  that Holders electing to have a Note purchased pursuant to any Asset
Sale Offer shall be required to surrender the Note, with the form entitled
"Option of Holder to Elect Purchase" on the reverse of the Note completed, or
transfer by book-entry transfer, to the Company, a depositary, if appointed by
the Company, or a Paying Agent at the address specified in the notice at least
three days before the Purchase Date;

     (g)  that Holders shall be entitled to withdraw their election if the
Company, the depositary or the Paying Agent, as the case may be, receives, not
later than the expiration of the Offer Period, a telegram, telex, facsimile
transmission or letter setting forth the name of the Holder, the principal
amount of the Note the Holder delivered for purchase and a statement that such
Holder is withdrawing his election to have such Note purchased;

     (h)  that, if the aggregate principal amount (or accreted value, as
applicable) of Notes and other senior Indebtedness of the Company surrendered by
Holders exceeds the Offer Amount, the Company shall select the Notes to be
purchased on a pro rata basis (with such adjustments as may be deemed
appropriate by the Company so that only Notes in denominations of $1,000, or
integral multiples thereof, shall be purchased); and

     (i)  that Holders whose Notes were purchased only in part shall be issued
new Notes equal in principal amount to the unpurchased portion of the Notes
surrendered (or transferred by book-entry transfer).

     On or before the Purchase Date, the Company shall, to the extent lawful,
accept for payment, on a pro rata basis to the extent necessary, the Offer
Amount of Notes or portions thereof tendered pursuant to the Asset Sale Offer,
or if less than the Offer Amount has been tendered, all Notes and other senior
Indebtedness tendered, and shall deliver to the Trustee an Officers' Certificate
stating that such Notes or portions thereof were accepted for payment by the
Company in accordance with the terms of this Section 3.09. The Company, the
Depositary or the Paying Agent, as the case may be, shall promptly (but in any
case not later than five days after the Purchase Date) mail or deliver to each
tendering Holder an amount equal to the purchase price of the Notes tendered by
such Holder and accepted by the Company for purchase, and the Company shall
promptly issue a new Note, and the Trustee, upon written request from the
Company shall authenticate and mail or deliver such new Note to such Holder, in
a principal amount equal to any unpurchased portion of the Note surrendered. Any
Note not so accepted shall be promptly mailed or delivered by the Company to the
Holder thereof. The Company shall publicly announce the results of the Asset
Sale Offer on the Purchase Date.

     Other than as specifically provided in this Section 3.09, any purchase
pursuant to this Section 3.09 shall be made pursuant to the provisions of
Sections 3.01 through 3.06 hereof.

                                       41
<PAGE>

                                   ARTICLE 4
                                   COVENANTS

Section 4.01.  Payment of Notes.

     The Company shall pay or cause to be paid the principal of, premium, if
any, and interest on the Notes on the dates and in the manner provided in the
Notes. Principal, premium, if any, and interest shall be considered paid on the
date due if the Paying Agent, if other than the Company or a Subsidiary thereof,
holds as of 10:00 a.m. Eastern Time on the due date money deposited by the
Company in immediately available funds and designated for and sufficient to pay
all principal, premium, if any, and interest then due.

     The Company shall pay interest (including post-petition interest in any
proceeding under any Bankruptcy Law) on overdue principal at the rate equal to
1% per annum in excess of the then applicable interest rate on the Notes to the
extent lawful; it shall pay interest (including post-petition interest in any
proceeding under any Bankruptcy Law) on overdue installments of interest
(without regard to any applicable grace period) at the same rate to the extent
lawful.

Section 4.02.  Maintenance of Office or Agency.

     The Company shall maintain in the Borough of Manhattan, the City of New
York, an office or agency (which may be an office of the Trustee or an affiliate
of the Trustee, Registrar or co-registrar) where Notes may be surrendered for
registration of transfer or for exchange and where notices and demands to or
upon the Company in respect of the Notes and this Indenture may be served. The
Company shall give prompt written notice to the Trustee of the location, and any
change in the location, of such office or agency. If at any time the Company
shall fail to maintain any such required office or agency or shall fail to
furnish the Trustee with the address thereof, such presentations, surrenders,
notices and demands may be made or served at the Corporate Trust Office of the
Trustee.

     The Company may also from time to time designate one or more other offices
or agencies where the Notes may be presented or surrendered for any or all such
purposes and may from time to time rescind such designations; provided, however,
that no such designation or rescission shall in any manner relieve the Company
of its obligation to maintain an office or agency in the Borough of Manhattan,
the City of New York, for such purposes. The Company shall give prompt written
notice to the Trustee of any such designation or rescission and of any change in
the location of any such other office or agency.

     The Company hereby designates the Corporate Trust Office of the Trustee as
one such office or agency of the Company in accordance with Section 2.03 hereof.

Section 4.03.  Reports.

     Whether or not required by the SEC, so long as any Notes are outstanding,
the Company shall furnish to the Holders of Notes:

          (1)  quarterly and annual financial information that would be required
     to be contained in a filing with the SEC on Forms 10-Q and 10-K if the
     Company were required to file such Forms, including a "Management's
     Discussion and Analysis of Financial Condition and Results of Operations"
     that describes the financial condition and results of operations of the

                                       42
<PAGE>

     Company and its consolidated Subsidiaries (showing in reasonable detail, in
     the footnotes to the financial statements and in the "Management's
     Discussion and Analysis of Financial Condition and Results of Operations"
     (in each case to the extent not prohibited by the SEC's rules and
     regulations):

               (a)  the financial condition and results of operations of the
          Company and its Restricted Subsidiaries separate from the financial
          condition and results of operations of the Unrestricted Subsidiaries
          of the Company; and

               (b)  the Tower Cash Flow for the most recently completed fiscal
          quarter and the Adjusted Consolidated Cash Flow for the most recently
          completed four-quarter period) and, with respect to the annual
          information only, a report thereon by the Company's certified
          independent accountants; and

          (2)  all current reports that would be required to be filed with the
     SEC on Form 8-K if the Company were required to file such reports, in each
     case within the time periods specified in the SEC's rules and regulations.

          (3)  For so long as any Notes remain outstanding, the Company shall
     furnish to the Holders and to securities analysts and prospective
     investors, upon their request, the information required to be delivered
     pursuant to Rule 144A(d)(4) under the Securities Act.

     In addition, whether or not required by the rules and regulations of the
SEC, the Company shall file a copy of all such information and reports with the
SEC for public availability within the time periods specified in the SEC's rules
and regulations (unless the SEC will not accept such a filing) and make such
information available to securities analysts and prospective investors upon
request. The Company shall at all times comply with TIA (S). 314(a).

Section 4.04.  Compliance Certificate.

          (1)  The Company shall deliver to the Trustee, within 90 days after
     the end of each fiscal year, an Officers' Certificate stating that a review
     of the activities of the Company and its Subsidiaries during the preceding
     fiscal year has been made under the supervision of the signing Officers
     with a view to determining whether the Company has kept, observed,
     performed and fulfilled its obligations under this Indenture, and further
     stating, as to each such Officer signing such certificate, that to the best
     of his or her knowledge the Company has kept, observed, performed and
     fulfilled each and every covenant contained in this Indenture and is not in
     default in the performance or observance of any of the terms, provisions
     and conditions of this Indenture (or, if a Default or Event of Default
     shall have occurred, describing all such Defaults or Events of Default of
     which he or she may have knowledge and what action the Company is taking or
     proposes to take with respect thereto) and that to the best of his or her
     knowledge no event has occurred and remains in existence by reason of which
     payments on account of the principal of or interest, if any, on the Notes
     is prohibited or if such event has occurred, a description of the event and
     what action the Company is taking or proposes to take with respect thereto.

          (2)  So long as not contrary to the then current recommendations of
     the American Institute of Certified Public Accountants, the year-end
     financial statements delivered pursuant to Section 4.03(a) above shall be
     accompanied by a written statement of the Company's

                                       43
<PAGE>

     independent public accountants (who shall be a firm of established national
     reputation) that in making the examination necessary for certification of
     such financial statements, nothing has come to their attention that would
     lead them to believe that the Company has violated any provisions of
     Article 4 or Article 5 hereof or, if any such violation has occurred,
     specifying the nature and period of existence thereof, it being understood
     that such accountants shall not be liable directly or indirectly to any
     Person for any failure to obtain knowledge of any such violation.

          (3)  The Company shall, so long as any of the Notes are outstanding,
     deliver to the Trustee, forthwith upon any Officer becoming aware of any
     Default or Event of Default, an Officers' Certificate specifying such
     Default or Event of Default and what action the Company is taking or
     proposes to take with respect thereto.

Section 4.05.  Taxes.

     The Company shall pay, and shall cause each of its Subsidiaries to pay,
prior to delinquency, all material taxes, assessments, and governmental levies
except such as are contested in good faith and by appropriate proceedings or
where the failure to effect such payment is not adverse in any material respect
to the Holders of the Notes.

Section 4.06.  Stay, Extension and Usury Laws.

     The Company covenants (to the extent that it may lawfully do so) that it
shall not at any time insist upon, plead, or in any manner whatsoever claim or
take the benefit or advantage of, any stay, extension or usury law wherever
enacted, now or at any time hereafter in force, that may affect the covenants or
the performance of this Indenture; and the Company (to the extent that it may
lawfully do so) hereby expressly waives all benefit or advantage of any such
law, and covenants that it shall not, by resort to any such law, hinder, delay
or impede the execution of any power herein granted to the Trustee, but shall
suffer and permit the execution of every such power as though no such law has
been enacted.

Section 4.07.  Restricted Payments.

     The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, directly or indirectly:

          (1)  declare or pay any dividend or make any other payment or
     distribution on account of the Company's or any of its Restricted
     Subsidiaries' Equity Interests (including, without limitation, any payment
     in connection with any merger or consolidation involving the Company or any
     of its Restricted Subsidiaries) or to the direct or indirect holders of the
     Company's or any of its Restricted Subsidiaries' Equity Interests in their
     capacity as such (other than dividends or distributions payable in Equity
     Interests (other than Disqualified Stock) of the Company or to the Company
     or a Restricted Subsidiary of the Company);

          (2)  purchase, redeem or otherwise acquire or retire for value
     (including without limitation, in connection with any merger or
     consolidation involving the Company) any Equity Interests of the Company or
     any direct or indirect parent of the Company (other than any such Equity
     Interests owned by the Company or any of its Restricted Subsidiaries);

                                       44
<PAGE>

          (3)  make any payment on or with respect to, or purchase, redeem,
     defease or otherwise acquire or retire for value any Indebtedness that is
     subordinated to the Notes, except a payment of interest or principal at
     Stated Maturity; or

          (4)  make any Restricted Investment, (all such payments and other
     actions set forth in these clauses (1) through (4) above, including those
     occurring since the date of the May 1999 Senior Discount Note Indenture,
     being collectively referred to as "Restricted Payments"),

unless, at the time of and after giving effect to such Restricted Payment:

          (1)  no Default has occurred and is continuing or would occur as a
     consequence of the Restricted Payment; and

          (2)  the Company would have been permitted to incur at least $1.00 of
     additional Indebtedness pursuant to the Debt to Adjusted Consolidated Cash
     Flow Ratio test set forth in the first paragraph of Section 4.09 hereof;
     provided that the Company and its Restricted Subsidiaries shall not be
     required to comply with this clause (2) in order to make any Restricted
     Investment; and

          (3)  such Restricted Payment, together with the aggregate amount of
     all other Restricted Payments made by the Company and its Restricted
     Subsidiaries after the date of the May 1999 Senior Discount Note Indenture
     (excluding Restricted Payments permitted by clauses (2), (3) and (4) of the
     paragraph of exceptions below), is less than the sum, without duplication,
     of:

               (a)  100% of the Consolidated Cash Flow of the Company for the
          period (taken as one accounting period) from the beginning of the
          fiscal quarter during which the May 1999 Senior Discount Note
          Indenture was executed to the end of the Company's most recently ended
          fiscal quarter for which internal financial statements are available
          at the time of such Restricted Payment (or, if the Consolidated Cash
          Flow for such period is a deficit, less 100% of the deficit), less
          1.75 times the Consolidated Interest Expense of the Company since the
          beginning of the fiscal quarter during which the May 1999 Senior
          Discount Note Indenture was executed; plus

               (b)  100% of the aggregate net cash proceeds received by the
          Company since the beginning of the fiscal quarter during which the May
          1999 Senior Discount Note Indenture was executed as a contribution to
          its common equity capital or from the issue or sale of Equity
          Interests of the Company (other than Disqualified Stock and except to
          the extent such net cash proceeds are used to incur new Indebtedness
          outstanding pursuant to clause (11) of the second paragraph of Section
          4.09 hereof) or from the issue or sale of Disqualified Stock or debt
          securities of the Company that have been converted into Equity
          Interests (other than Equity Interests (or Disqualified Stock or
          convertible debt securities) sold to a Subsidiary of the Company and
          other than Disqualified Stock or convertible debt securities that have
          been converted into Disqualified Stock); plus

               (c)  to the extent that any Restricted Investment that was made
          after the date of the May 1999 Senior Discount Note Indenture is sold
          for cash or otherwise liquidated or repaid for cash, the lesser of:

                                       45
<PAGE>

                    (A)  the cash return of capital with respect to the
               Restricted Investment (less the cost of disposition, if any); and

                    (B)  the initial amount of the Restricted Investment; plus

               (d)  to the extent that any Unrestricted Subsidiary of the
          Company and all of its Subsidiaries are designated as Restricted
          Subsidiaries after the date of the May 1999 Senior Discount Note
          Indenture, the lesser of:

                    (A)  the fair market value of the Company's Investments in
               such Subsidiaries as of the date of such designation; or

                    (B)  the sum of:

                              (x)  the fair market value of the Company's
                    Investments in such Subsidiaries as of the date on which
                    such Subsidiaries were originally designated as Unrestricted
                    Subsidiaries; and

                              (y)  the amount of any Investments made in such
                    Subsidiaries subsequent to such designation (and treated as
                    Restricted Payments) by the Company or any Restricted
                    Subsidiary;

               provided that:

                    (i)  in the event the Unrestricted Subsidiaries designated
               as Restricted Subsidiaries are CTSH and its Subsidiaries, the
               references in clauses (A) and (B) of this clause (d) to fair
               market value of the Company's Investments in such Subsidiaries
               shall mean the amount by which the fair market value of all such
               Investments exceeds 34.3% of the fair market value of CTSH and
               its Subsidiaries as a whole; and

                    (ii) in the event the Unrestricted Subsidiaries designated
               as Restricted Subsidiaries are CCAIC and its Subsidiaries, the
               references in clauses (A) and (B) of this clause (d) to fair
               market value of the Company's Investments in such Subsidiaries
               shall mean the amount by which the fair market value of all such
               Investments exceeds $250.0 million; plus

               (e)  50% of any dividends received by the Company or a Restricted
          Subsidiary after the date of the May 1999 Senior Discount Note
          Indenture from an Unrestricted Subsidiary of the Company, to the
          extent that such dividends were not otherwise included in Consolidated
          Net Income of the Company for such period.

     The preceding provisions shall not prohibit:

          (1)  the payment of any dividend within 60 days after the date of
     declaration of that dividend, if at said date of declaration such payment
     would have complied with the provisions of this Indenture;

                                       46
<PAGE>

          (2)  the making of any Investment or the redemption, repurchase,
     retirement, defeasance or other acquisition of any subordinated
     Indebtedness or Equity Interests of the Company in exchange for, or out of
     the net cash proceeds from the sale since the beginning of the fiscal
     quarter during which the May 1999 Senior Discount Note Indenture was
     executed (other than to a Subsidiary of the Company) of Equity Interests of
     the Company (other than any Disqualified Stock); provided that the net cash
     proceeds are not used to incur new Indebtedness pursuant to clause (11) of
     the second paragraph of Section 4.09 hereof); and provided further that, in
     each case, the amount of any net cash proceeds that are so utilized will be
     excluded from clause (3)(b) of the preceding paragraph;

          (3)  the defeasance, redemption, repurchase or other acquisition of
     subordinated Indebtedness with the net cash proceeds from an incurrence of
     Permitted Refinancing Indebtedness;

          (4)  the payment of any dividend by a Restricted Subsidiary of the
     Company to the holders of its Equity Interests on a pro rata basis;

          (5)  the repurchase, redemption or other acquisition or retirement for
     value of any Equity Interests of the Company or any Restricted Subsidiary
     of the Company held by any member of the Company's (or any of its
     Restricted Subsidiaries') management pursuant to any management equity
     subscription agreement or stock option agreement in effect as of the date
     of the May 1999 Senior Discount Note Indenture; provided that the aggregate
     price paid for all of the repurchased, redeemed, acquired or retired Equity
     Interests may not exceed (a) $500,000 in any twelve-month period and (b)
     $5.0 million in the aggregate since the date of the August 1999 Senior Note
     Indenture; or

          (6)  the payment of scheduled dividends on the Company's 123/4% Senior
     Exchangeable Preferred Stock due 2010, whether paid in cash or in kind
     through the issuance of additional shares of such preferred stock, all in
     accordance with the certificate of designations governing such preferred
     stock as in effect on the date of the May 1999 Senior Discount Note
     Indenture.

     The Board of Directors may designate any Restricted Subsidiary to be an
Unrestricted Subsidiary if such designation would not cause a Default. For
purposes of making such determination, all outstanding Investments by the
Company and its Restricted Subsidiaries (except to the extent repaid in cash) in
the Subsidiary so designated will be deemed to be Restricted Payments at the
time of the designation and will reduce the amount available for Restricted
Payments under the first paragraph in this Section 4.07. All of those
outstanding Investments will be deemed to constitute Investments in an amount
equal to the fair market value of the Investments at the time of such
designation. Such designation will only be permitted if the Restricted Payment
would be permitted at the time and if the Restricted Subsidiary otherwise meets
the definition of an Unrestricted Subsidiary. The Board of Directors may
designate any Unrestricted Subsidiary to be a Restricted Subsidiary if the
designation would not cause a Default.

     The amount of all Restricted Payments (other than cash) will be the fair
market value on the date of the Restricted Payment of the assets or securities
proposed to be transferred or issued by the Company or the applicable Restricted
Subsidiary, as the case may be, pursuant to the Restricted Payment. The fair
market value of any property, assets or Investments required by this covenant to
be valued will be valued

                                       47
<PAGE>

by the Board of Directors whose resolution with respect to the determination
will be delivered to the Trustee.

Section 4.08.  Dividend and Other Payment Restrictions Affecting Subsidiaries.

     The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, directly or indirectly, create or otherwise cause or suffer to
exist or become effective any encumbrance or restriction on the ability of any
Restricted Subsidiary to:

          (1)  pay dividends or make any other distributions to the Company or
     any of its Restricted Subsidiaries on its Capital Stock or with respect to
     any other interest or participation in, or measured by, its profits;

          (2)  pay any indebtedness owed to the Company or any of its Restricted
     Subsidiaries;

          (3)  make loans or advances to the Company or any of its Restricted
Subsidiaries; or

          (4)  transfer any of its properties or assets to the Company or any of
     its Restricted Subsidiaries.

     The preceding restrictions shall not apply to encumbrances or restrictions
existing under or by reason of:

          (1)  Existing Indebtedness as in effect on the date hereof, and any
     amendments, modifications, restatements, renewals, increases, supplements,
     refundings, replacements or refinancings thereof; provided that such
     amendments, modifications, restatements, renewals, increases, supplements,
     refundings, replacements or refinancings are no more restrictive, taken as
     a whole, with respect to such dividend and other payment restrictions than
     those contained in the applicable series of Existing Indebtedness as in
     effect on the date hereof;

          (2)  Indebtedness of any Restricted Subsidiary under any Credit
     Facility that is permitted to be incurred pursuant to Section 4.09 hereof;
     provided that such Credit Facility and Indebtedness contain only such
     encumbrances and restrictions on such Restricted Subsidiary's ability to
     engage in the activities set forth in clauses (1) through (4) of the
     preceding paragraph as are, at the time such Credit Facility is entered
     into or amended, modified, restated, renewed, increased, supplemented,
     refunded, replaced or refinanced, ordinary and customary for a Credit
     Facility of that type as determined in the good faith judgment of the Board
     of Directors (and evidenced in a board resolution), which determination
     shall be conclusively binding;

          (3)  encumbrances and restrictions applicable to any Unrestricted
     Subsidiary, as the same are in effect as of the date on which the
     Subsidiary becomes a Restricted Subsidiary, and as the same may be amended,
     modified, restated, renewed, increased, supplemented, refunded, replaced or
     refinanced; provided that such amendments, modifications, restatements,
     renewals, increases, supplements, refundings, replacement or refinancings
     are no more restrictive, taken as a whole, with respect to the dividend and
     other payment restrictions than those contained in the applicable series of
     Indebtedness of such Subsidiary as in effect on the date on which such
     Subsidiary becomes a Restricted Subsidiary;

                                       48
<PAGE>

          (4)  any Indebtedness incurred in compliance with Section 4.09 hereof
     or any agreement pursuant to which such Indebtedness is issued if the
     encumbrance or restriction applies only in the event of a payment default
     or default with respect to a financial covenant contained in the
     Indebtedness or agreement and the encumbrance or restriction is not
     materially more disadvantageous to the Holders of the Notes than is
     customary in comparable financings (as determined by the Company) and the
     Company determines that any such encumbrance or restriction will not
     materially affect the Company's ability to pay interest or principal on the
     Notes;

          (5)  this Indenture;

          (6)  applicable law;

          (7)  any instrument governing Indebtedness or Capital Stock of a
     Person acquired by the Company or any of its Restricted Subsidiaries as in
     effect at the time that Person is acquired by the Company (except to the
     extent the Indebtedness was incurred in connection with or in contemplation
     of the acquisition), which encumbrance or restriction is not applicable to
     any Person, or the properties or assets of any Person, other than the
     Person, or the property or assets of the Person, so acquired, provided
     that, in the case of Indebtedness, the Indebtedness was permitted by the
     terms hereof to be incurred;

          (8)  customary non-assignment provisions in leases or licenses entered
     into in the ordinary course of business;

          (9)  purchase money obligations for property acquired in the ordinary
     course of business that impose restrictions of the nature described in
     clause (5) in the second paragraph of Section 4.09 hereof on the property
     so acquired;

          (10) the provisions of agreements governing Indebtedness incurred
     pursuant to clause (4) of the second paragraph of Section 4.09 hereof;

          (11) any agreement for the sale of a Restricted Subsidiary that
     restricts that Restricted Subsidiary pending its sale;

          (12) Permitted Refinancing Indebtedness, provided that the
     restrictions contained in the agreements governing the Permitted
     Refinancing Indebtedness are no more restrictive, taken as a whole, than
     those contained in the agreements governing the Indebtedness being
     refinanced;

          (13) Liens permitted to be incurred pursuant to the provisions of
     Section 4.12 hereof that limit the right of the debtor to transfer the
     assets subject to such Liens;

          (14) provisions with respect to the disposition or distribution of
     assets or property in joint venture agreements and other similar
     agreements; and

          (15) restrictions on cash or other deposits or net worth imposed by
     customers under contracts entered into in the ordinary course of business.

Section 4.09.  Incurrence of Indebtedness and Issuance of Preferred Stock.

                                       49
<PAGE>

     The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, directly or indirectly, create, incur, issue, assume, guarantee
or otherwise become directly or indirectly liable, contingently or otherwise,
with respect to (collectively, "incur") any Indebtedness (including Acquired
Debt) and the Company will not issue any Disqualified Stock and will not permit
any of its Restricted Subsidiaries to issue any shares of preferred stock;
provided that the Company may incur Indebtedness (including Acquired Debt) or
issue shares of Disqualified Stock and the Company's Restricted Subsidiaries may
incur Indebtedness (including Acquired Debt) or issue preferred stock if, in
each case, the Company's Debt to Adjusted Consolidated Cash Flow Ratio at the
time of incurrence of the Indebtedness or the issuance of the preferred stock,
after giving pro forma effect to such incurrence or issuance as of such date and
to the use of proceeds from such incurrence or issuance as if the same had
occurred at the beginning of the most recently ended four full fiscal quarter
period of the Company for which internal financial statements are available,
would have been no greater than 7.5 to 1.

     The provisions of the first paragraph of this Section 4.09 shall not
prohibit the incurrence of any of the following items of Indebtedness or to the
issuance of any of the following items of Disqualified Stock or preferred stock
(collectively, "Permitted Debt"):

          (1)  the incurrence by the Company or any of its Restricted
     Subsidiaries of Indebtedness under Credit Facilities since the date of the
     August 1999 Senior Note Indenture in an aggregate principal amount (with
     letters of credit being deemed to have a principal amount equal to the
     maximum potential liability of the Company and its Restricted Subsidiaries
     thereunder) at any one time outstanding not to exceed the product of
     $150,000 times the number of Completed Towers on the date of such
     incurrence;

          (2)  the incurrence by the Company and its Restricted Subsidiaries of
     the Existing Indebtedness;

          (3)  the incurrence by the Company of the Indebtedness represented by
     notes issued on the date of the May 1999 Senior Discount Note Indenture;

          (4)  the issuance by the Company of additional shares of its 12 3/4%
     Senior Exchangeable Preferred Stock due 2010 solely for the purpose of
     paying dividends thereon and the incurrence by the Company of Indebtedness
     represented by the Company's 12 3/4% Senior Subordinated Exchange
     Debentures due 2010;

          (5)  the incurrence by the Company or any of its Restricted
     Subsidiaries of Indebtedness since the date of the August 1999 Senior Note
     Indenture represented by Capital Lease Obligations, mortgage financings or
     purchase money obligations, in each case incurred for the purpose of
     financing all or any part of the purchase price or cost of construction or
     improvement of property, plant or equipment used in the business of the
     Company or such Restricted Subsidiary, in an aggregate principal amount,
     including all Permitted Refinancing Indebtedness incurred to refund,
     refinance or replace any other Indebtedness incurred pursuant to this
     clause (5), not to exceed $10.0 million at any one time outstanding;

          (6)  the incurrence by the Company or any of its Restricted
     Subsidiaries of Permitted Refinancing Indebtedness in exchange for, or the
     net proceeds of which are used to extend, refinance, renew, replace,
     defease or refund Indebtedness of the Company or any of its Restricted
     Subsidiaries or Disqualified Stock of the Company (other than intercompany

                                       50
<PAGE>

     Indebtedness) that was permitted by this Indenture to be incurred under the
     first paragraph of this Section 4.09 or clauses (2), (3), (4), (5) or this
     clause (6) of this paragraph;

          (7)  the incurrence by the Company or any of its Restricted
     Subsidiaries of intercompany Indebtedness between or among the Company and
     any of its Restricted Subsidiaries; provided, however, that:

               (i)  if the Company is the obligor on such Indebtedness, such
          Indebtedness is expressly subordinated to the prior payment in full in
          cash of all Obligations with respect to the Notes of such series and
          that:

               (ii) (A)  any subsequent issuance or transfer of Equity Interests
          that results in any such Indebtedness being held by a Person other
          than the Company or a Restricted Subsidiary; and

                    (B)  any sale or other transfer of any such Indebtedness to
          a Person that is not either the Company or a Restricted Subsidiary,

               shall be deemed, in each case, to constitute an incurrence of the
          Indebtedness by the Company or the Restricted Subsidiary, as the case
          may be;

          (8)  the incurrence by the Company or any of its Restricted
     Subsidiaries of Hedging Obligations that are incurred for the purpose of
     fixing or hedging interest rate risk with respect to any floating rate
     Indebtedness that is permitted by the terms of this Indenture to be
     outstanding or currency exchange risk;

          (9)  the guarantee by the Company or any of its Restricted
     Subsidiaries of Indebtedness of the Company or a Restricted Subsidiary of
     the Company that was permitted to be incurred by another provision of this
     Indenture;

          (10) the incurrence by the Company or any of its Restricted
     Subsidiaries of Acquired Debt in connection with the acquisition of assets
     or a new Subsidiary and the incurrence by the Company's Restricted
     Subsidiaries of Indebtedness as a result of the designation of an
     Unrestricted Subsidiary as a Restricted Subsidiary; provided that, in the
     case of any such incurrence of Acquired Debt, such Acquired Debt was
     incurred by the prior owner of such assets or such Restricted Subsidiary
     prior to such acquisition by the Company or one of its Restricted
     Subsidiaries and was not incurred in connection with, or in contemplation
     of, the acquisition by the Company or one of its Restricted Subsidiaries;
     and provided further that, in the case of any incurrence pursuant to this
     clause (10), as a result of such acquisition by the Company or one of its
     Restricted Subsidiaries, the Company's Debt to Adjusted Consolidated Cash
     Flow Ratio at the time of incurrence of such Acquired Debt, after giving
     pro forma effect to such incurrence as if the same had occurred at the
     beginning of the most recently ended four full fiscal quarter period of the
     Company for which internal financial statements are available, would have
     been less than the Company's Debt to Adjusted Consolidated Cash Flow Ratio
     for the same period without giving pro forma effect to such incurrence;

          (11) the incurrence by the Company or any of its Restricted
     Subsidiaries of Indebtedness or Disqualified Stock not to exceed, at any
     one time outstanding, the sum of:

                                       51
<PAGE>

               (i)  2.0 times the aggregate net cash proceeds; plus

               (ii) 1.0 times the fair market value of non-cash proceeds
          (evidenced by a resolution of the Board of Directors set forth in an
          Officers' Certificate delivered to the Trustee); in each case, from
          the issuance and sale, other than to a Subsidiary, of Equity Interests
          (other than Disqualified Stock) of the Company since the beginning of
          the fiscal quarter during which the May 1999 Senior Discount Note
          Indenture was executed (less the amount of such proceeds used to make
          Restricted Payments as provided in clause (3)(b) of the first
          paragraph or clause (2) of the second paragraph of Section 4.07
          hereof); and

          (12) the incurrence by the Company or any of its Restricted
     Subsidiaries since the date of the August 1999 Senior Note Indenture of
     additional Indebtedness and/or the issuance by the Company of Disqualified
     Stock in an aggregate principal amount, accreted value or liquidation
     preference, as applicable, at any time outstanding, not to exceed $25.0
     million.

          In addition, the Company shall not:

          (1)  incur any Indebtedness that is contractually subordinated in
     right of payment to any other Indebtedness of the Company unless such
     Indebtedness is also contractually subordinated in right of payment to the
     Notes on substantially identical terms; provided, however, that no
     Indebtedness of the Company will be deemed to be contractually subordinated
     in right of payment to any other Indebtedness of the Company solely by
     virtue of being unsecured; and

          (2)  permit any of its Unrestricted Subsidiaries to incur any
     Indebtedness other than Non-Recourse Debt.

     For purposes of determining compliance with this Section 4.09, in the event
that an item of Indebtedness meets the criteria of more than one of the
categories of Permitted Debt described in clauses (1) through (12) above or is
entitled to be incurred pursuant to the first paragraph of this Section 4.09,
the Company shall, in its sole discretion, classify (or later reclassify in
whole or in part) such item of Indebtedness in any manner that complies with
this Section 4.09. Accrual of interest, accretion or amortization of original
issue discount and the payment of interest in the form of additional
Indebtedness shall not be deemed to be an incurrence of Indebtedness for
purposes of this Section 4.09. Indebtedness under Credit Facilities outstanding
on the date hereof shall be deemed to have been incurred on such date in
reliance on the exception provided by clause (1) of the definition of Permitted
Debt. The debt represented by the Notes issued on the date hereof shall be
deemed to have been incurred on such date in reliance on the exception provided
by clause (11) of the definition of Permitted Debt and the exchange notes to be
issued in exchange for the Notes shall be deemed to be a Permitted Refinancing
under such clause (11).

Section 4.10.  Asset Sales.

     The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, consummate an Asset Sale unless:

                                       52
<PAGE>

          (1)  the Company (or the Restricted Subsidiary, as the case may be)
     receives consideration at the time of the Asset Sale at least equal to the
     fair market value of the assets or Equity Interests issued or sold or
     otherwise disposed of;

          (2)  fair market value is determined by the Board of Directors and
     evidenced by a resolution of the Board of Directors set forth in an
     Officers' Certificate delivered to the Trustee; and

          (3)  except in the case of a Tower Asset Exchange, at least 75% of the
     consideration received in such Asset Sale by the Company or such Restricted
     Subsidiary is in the form of cash or Cash Equivalents.

     For purposes of this provision, each of the following shall be deemed to be
cash:

               (a)  any liabilities, as shown on the Company's or such
          Restricted Subsidiary's most recent balance sheet, of the Company's or
          any Restricted Subsidiary (other than contingent liabilities and
          liabilities that are by their terms subordinated to the Notes or any
          guarantee of the Notes) that are assumed by the transferee of any
          assets pursuant to a customary novation agreement that releases the
          Company or the Restricted Subsidiary from further liability; and

               (b)  any securities, notes or other obligations received by the
          Company or any Restricted Subsidiary from the transferee that are
          converted by the Company or the Restricted Subsidiary into cash within
          20 days of the applicable Asset Sale, to the extent of the cash
          received in that conversion.

     Within 365 days after the receipt of any Net Proceeds from an Asset Sale,
the Company or the Restricted Subsidiary may apply those Net Proceeds to:

          (1)  reduce Indebtedness under a Credit Facility;

          (2)  reduce other Indebtedness of any of the Restricted Subsidiaries;

          (3)  the acquisition of all or substantially all the assets of a
     Permitted Business;

          (4)  the acquisition of Voting Stock of a Permitted Business from a
     Person that is not a Subsidiary of the Company; provided that, after giving
     effect to the acquisition, the Company or its Restricted Subsidiary owns a
     majority of the Voting Stock of that business; or

          (5)  the making of a capital expenditure or the acquisition of other
     long-term assets that are used or useful in a Permitted Business.

     Pending the final application of any Net Proceeds, the Company may
temporarily reduce revolving credit borrowings or otherwise invest the Net
Proceeds in any manner that is not prohibited by this Indenture.

     Any Net Proceeds from Asset Sales that are not applied or invested as
provided in the preceding paragraph shall be deemed to constitute "Excess
Proceeds". When the aggregate amount of Excess Proceeds exceeds $10.0 million,
the Company shall make an Asset Sale Offer to all Holders of Notes,

                                       53
<PAGE>

and all holders of other senior Indebtedness of the Company containing
provisions similar to those set forth in this Indenture with respect to offers
to purchase or redeem with the proceeds of sales of assets, to purchase the
maximum principal amount of Notes and such other senior Indebtedness of the
Company that may be purchased out of the Excess Proceeds. The offer price in any
Asset Sale Offer will be payable in cash and will be 100% of the principal
amount of the Notes, plus accrued and unpaid interest to the date of purchase,
if any. In the case of any other senior Indebtedness, the offer price shall be
100% of the principal amount of the Indebtedness plus accrued and unpaid
interest thereon, if any, to the date of purchase. Each Asset Sale Offer shall
be made in accordance with the procedures set forth herein and the other senior
Indebtedness of the Company. If any Excess Proceeds remain after consummation of
an Asset Sale Offer, the Company may use the remaining Excess Proceeds for any
purpose not otherwise prohibited by this Indenture. If the aggregate principal
amount, as applicable, of Notes and the other senior Indebtedness of the Company
tendered into the Asset Sale Offer exceeds the amount of Excess Proceeds, the
Trustee shall select the Notes and such other senior Indebtedness to be
purchased on a pro rata basis. Upon completion of the Asset Sale Offer, the
amount of Excess Proceeds shall be reset at zero.

Section 4.11.  Transactions with Affiliates.

     The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, make any payment to, or sell, lease, transfer or otherwise
dispose of any of its properties or assets to, or purchase any property or
assets from, or enter into or make or amend any transaction, contract,
agreement, understanding, loan, advance or guarantee with, or for the benefit
of, any Affiliate (each of the foregoing, an "Affiliate Transaction"), unless:

          (1)  such Affiliate Transaction is on terms that are no less favorable
     to the Company or the relevant Restricted Subsidiary than those that would
     have been obtained in a comparable transaction by the Company or such
     Restricted Subsidiary with an unrelated Person; and

          (2)  the Company delivers to the Trustee:

               (a)  with respect to any Affiliate Transaction or series of
          related Affiliate Transactions involving aggregate consideration in
          excess of $1.0 million, a resolution of the Board of Directors set
          forth in an Officers' Certificate certifying that the Affiliate
          Transaction complies with clause (1) above and that the Affiliate
          Transaction has been approved by a majority of the disinterested
          members of the Board of Directors; and

               (b)  with respect to any Affiliate Transaction or series of
          related Affiliate Transactions involving aggregate consideration in
          excess of $10.0 million, an opinion to the Holders of the Notes as to
          the fairness of the Affiliate Transaction from a financial point of
          view issued by an accounting, appraisal or investment banking firm of
          national standing.

     Notwithstanding the foregoing, the following items shall not be deemed
Affiliate Transactions:

          (1)  any employment arrangements with any executive officer of the
     Company or a Restricted Subsidiary that is entered into by the Company or
     any of its Restricted Subsidiaries in the ordinary course of business and
     consistent with compensation arrangements of similarly situated executive
     officers at comparable companies engaged in Permitted Businesses;

                                       54
<PAGE>

          (2)  transactions between or among the Company and/or its Restricted
     Subsidiaries;

          (3)  payment of directors fees in an aggregate annual amount not to
     exceed $25,000 per Person;

          (4)  Restricted Payments that are permitted under Section 4.07 hereof;

          (5)  the issuance or sale of Equity Interests (other than Disqualified
     Stock) of the Company; and

          (6)  transactions pursuant to the provisions of the Governance
     Agreement and the Stockholders' Agreement, as the same are in effect on the
     date hereof.

Section 4.12.  Liens.

     The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, directly or indirectly, create, incur, assume or suffer to
exist any Lien securing Indebtedness or trade payables on any asset now owned or
hereafter acquired, or any income or profits therefrom or assign or convey any
right to receive income therefrom, except Permitted Liens.

Section 4.13.  Business Activities.

     The Company shall not, and shall not permit any Subsidiary to, engage in
any business other than Permitted Businesses, except to the extent as would not
be material to the Company and its Subsidiaries taken as a whole.

Section 4.14.  Corporate Existence.

     Subject to Article 5 hereof, the Company shall do or cause to be done all
things necessary to preserve and keep in full force and effect:

          (1)  its corporate existence, and the corporate, partnership or other
     existence of each of its Subsidiaries, in accordance with the respective
     organizational documents (as the same may be amended from time to time) of
     the Company or any such Subsidiary and

          (2)  the rights (charter and statutory), licenses and franchises of
     the Company and its Subsidiaries; provided, however, that the Company shall
     not be required to preserve any such right, license or franchise, or the
     corporate, partnership or other existence of any of its Subsidiaries, if
     the Board of Directors shall determine that the preservation thereof is no
     longer desirable in the conduct of the business of the Company and its
     Subsidiaries, taken as a whole, and that the loss thereof is not adverse in
     any material respect to the Holders of the Notes.

Section 4.15.  Offer to Repurchase Upon Change of Control.

     If a Change of Control occurs, the Company shall make an offer (a "Change
of Control Offer") to each Holder to repurchase all or any part (equal to $1,000
or an integral multiple thereof) of each Holder's Notes at a purchase price, in
cash, equal to 101% of the aggregate principal amount of the Notes repurchased,
plus accrued and unpaid interest thereon, if any, (subject to the right of
Holders of record on the relevant record date to receive interest due on the
relevant interest payment date), to the

                                       55
<PAGE>

date of purchase (the "Change of Control Payment"). Within 30 days following any
Change of Control, the Company shall mail a notice to each Holder describing the
transaction or transactions that constitute a change of control and stating:

          (1)  that the Change of Control Offer is being made pursuant to this
     covenant and that all Notes tendered will be accepted for payment;

          (2)  the purchase price and the purchase date, which shall be no
     earlier than 30 days and no later than 60 days from the date such notice is
     mailed (the "Change of Control Payment Date");

          (3)  that any Note not tendered will continue to accrue interest;

          (4)  that, unless the Company defaults in the payment of the Change of
     Control Payment, all Notes accepted for payment pursuant to the Change of
     Control Offer shall cease to accrue interest after the Change of Control
     Payment Date;

          (5)  that Holders electing to have any Notes purchased pursuant to a
     Change of Control Offer will be required to surrender the Notes, with the
     form entitled "Option of Holder to Elect Purchase" on the reverse of the
     Notes completed, to the Paying Agent at the address specified in the notice
     prior to the close of business on the third Business Day preceding the
     Change of Control Payment Date;

          (6)  that Holders will be entitled to withdraw their election if the
     Paying Agent receives, not later than the close of business on the second
     Business Day preceding the Change of Control Payment Date, a telegram,
     telex, facsimile transmission or letter setting forth the name of the
     Holder, the principal amount of Notes delivered for purchase, and a
     statement that such Holder is withdrawing his election to have the Notes
     purchased; and

          (7)  that Holders whose Notes are being purchased only in part will be
     issued new Notes equal in principal amount to the unpurchased portion of
     the Notes surrendered, which unpurchased portion must be equal to $1,000 in
     principal amount or an integral multiple thereof.

On the Change of Control Payment Date, the Company shall, to the extent lawful,

          (1)  accept for payment all Notes or portions of the Notes properly
     tendered pursuant to the Change of Control Offer;

          (2)  deposit with the Paying Agent an amount equal to the Change of
     Control Payment in respect of all Notes or portions of the Notes so
     tendered; and

          (3)  deliver or cause to be delivered to the Trustee the Notes so
     accepted together with an Officers' Certificate stating the aggregate
     principal amount of Notes or portions thereof being purchased by the
     Company.

     The Paying Agent shall promptly mail to each Holder of Notes properly
tendered payment in an amount equal to the purchase price for the Notes (the
"Change of Control Payment"), and the Trustee shall promptly authenticate and
mail (or cause to be transferred by book entry) to each Holder a new Note equal
in principal amount to any unpurchased portion of the Notes surrendered by such
Holder, if

                                       56
<PAGE>

any; provided, that each such new Note shall be in a principal amount of $1,000
or an integral multiple thereof. The Company shall publicly announce the results
of the Change of Control Offer on or as soon as practicable after the Change of
Control Payment Date.

     The Change of Control provisions described above shall be applicable
whether or not any other provisions of this Indenture are applicable. The
Company shall comply with the requirements of Section 14(e) of the Exchange Act
and any other securities laws or regulations to the extent those laws and
regulations are applicable to any Change of Control Offer. If the provisions of
any of the applicable securities laws or securities regulations conflict with
the provisions of this Section 4.15, the Company shall comply with the
applicable securities laws and regulations and shall not be deemed to have
breached its obligations under this Section 4.15 by virtue of the compliance.

     The Company shall not be required to make a Change of Control Offer upon a
Change of Control if a third party makes the Change of Control Offer in the
manner, at the times and otherwise in compliance with the requirements set forth
in this Indenture applicable to a Change of Control Offer made by the Company
and purchases all Notes properly tendered and not withdrawn under such Change of
Control Offer. The provisions under this Indenture relating to the Company's
obligation to make an offer to repurchase the Notes as a result of a Change of
Control may be waived or modified with the written consent of the Holders of a
at least a majority in principal amount of the Notes then outstanding.

Section 4.16.  Sale and Leaseback Transactions.

     The Company shall not, and shall not permit any of its Restricted
Subsidiaries to, enter into any sale and leaseback transaction; provided,
however, that the Company or any of its Restricted Subsidiaries may enter into a
sale and leaseback transaction if:

     (1)  the Company or such Restricted Subsidiary, as applicable, could have:

                    (a)  incurred Indebtedness in an amount equal to the
               Attributable Debt relating to such sale and leaseback transaction
               pursuant to the Debt to Adjusted Consolidated Cash Flow Ratio
               test set forth in the first paragraph of Section 4.09 hereof; or

                    (b)  incurred a Lien to secure such Indebtedness pursuant to
               the provisions of Section 4.12 hereof;

     (2)  the gross cash proceeds of such sale and leaseback transaction are at
least equal to the fair market value (as determined in good faith by the Board
of Directors) of the property that is the subject of the sale and leaseback
transaction; and

     (3)  the transfer of assets in the sale and leaseback transaction is
permitted by, and the Company applies the proceeds of such transaction in
compliance with, Section 4.10 hereof.

Section 4.17.  Limitation on Issuances and Sales of Capital Stock of Restricted
               Subsidiaries.

     The Company:

               (1)  shall not, and shall not permit any of its Restricted
     Subsidiaries to, transfer, convey, sell, lease or otherwise dispose of any
     Equity Interests in any Restricted Subsidiary of the

                                       57
<PAGE>

     Company to any Person (other than the Company or a Wholly Owned Restricted
     Subsidiary of the Company); and

               (2)  shall not permit any of its Restricted Subsidiaries to issue
     any of its Equity Interests (other than, if necessary, shares of its
     Capital Stock constituting directors' qualifying shares) to any Person
     other than to the Company or a Wholly Owned Restricted Subsidiary of the
     Company, unless, in each such case:

                         (a)  as a result of such transfer, conveyance, sale,
               lease or other disposition or issuance, such Restricted
               Subsidiary no longer constitutes a Subsidiary; and

                         (b)  the cash Net Proceeds from such transfer,
               conveyance, sale, lease or other disposition or issuance are
               applied in accordance with Section 4.10 hereof.

     Notwithstanding the foregoing, the issuance or sale of shares of Capital
Stock of any Restricted Subsidiary of the Company will not violate the
provisions of the immediately preceding sentence if such shares are issued or
sold in connection with (x) the formation or capitalization of a Restricted
Subsidiary or (y) a single transaction or a series of substantially
contemporaneous transactions whereby such Restricted Subsidiary becomes a
Restricted Subsidiary of the Company by reason of the acquisition of securities
or assets from another Person.

Section 4.18.  Limitation on Issuances of Guarantees of Indebtedness.

     The Company shall not permit any Restricted Subsidiary, directly or
indirectly, to Guarantee or pledge any assets to secure the payment of any other
Indebtedness of the Company unless such Subsidiary simultaneously executes and
delivers a supplemental indenture to this Indenture governing the Notes
providing for the Guarantee of the payment of the Notes by such Subsidiary,
which Guarantee shall be senior to or pari passu with such Subsidiary's
Guarantee of or pledge to secure such other Indebtedness. Notwithstanding the
foregoing, any Guarantee by a Subsidiary of the Notes shall provide by its terms
that it shall be automatically and unconditionally released and discharged upon
any sale, exchange or transfer, to any Person other than a Subsidiary of the
Company, of all of the Company's stock in, or all or substantially all the
assets of, such Subsidiary, which sale, exchange or transfer is made in
compliance with the applicable provisions of this Indenture. The form of such
Guarantee is attached as Exhibit F hereto.

                                   ARTICLE 5
                                  SUCCESSORS

Section 5.01.  Merger, Consolidation, or Sale of Assets.

     The Company shall not:

     (a)  consolidate or merge with or into (whether or not the Company is the
surviving corporation); or

     (b)  sell, assign, transfer, lease, convey or otherwise dispose of all or
substantially all of its properties or assets in one or more related
transactions, to another corporation, Person or entity, unless:

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<PAGE>

          (i)   either (A) the Company is the surviving corporation; or (B) the
     entity or the Person formed by or surviving any such consolidation or
     merger (if other than the Company) or to which the sale, assignment,
     transfer, lease, conveyance or other disposition shall have been made is a
     corporation organized or existing under the laws of the United States, any
     state thereof or the District of Columbia;

          (ii)  the entity or Person formed by or surviving any such
     consolidation or merger (if other than the Company) or the entity or Person
     to which the sale, assignment, transfer, lease, conveyance or other
     disposition shall have been made assumes all the Obligations of the Company
     under the Notes and this Indenture pursuant to a supplemental indenture in
     a form reasonably satisfactory to the Trustee;

          (iii) immediately after such transaction no Default exists; and

          (iv)  except in the case of (A) a merger of the Company with or into a
     Wholly Owned Restricted Subsidiary of the Company and (B) a merger entered
     into solely for the purpose of reincorporating the Company in another
     jurisdiction:

     (x)  in the case of a merger or consolidation in which the Company is the
surviving corporation, the Company's Debt to Adjusted Consolidated Cash Flow
Ratio at the time of the transaction, after giving pro forma effect to the
transaction as of such date for balance sheet purposes and as if the transaction
had occurred at the beginning of the most recently ended four full fiscal
quarter period of the Company for which internal financial statements are
available for income statement purposes, would have been less than the Company's
Debt to Adjusted Consolidated Cash Flow Ratio for the same period without giving
pro forma effect to such transaction, or

     (y)  in the case of any other such transaction, the Debt to Adjusted
Consolidated Cash Flow of the entity or Person formed by or surviving any such
consolidation or merger (if other than the Company), or to which the sale,
assignment, transfer, lease, conveyance or other disposition shall have been
made, at the time of the transaction, after giving pro forma effect to the
transaction as of such date for balance sheet purposes and as if such
transaction had occurred at the beginning of the most recently ended four full
fiscal quarter period of such entity or Person for which internal financial
statements are available for income statement purposes, would have been less
than the Company's Debt to Adjusted Consolidated Cash Flow Ratio for the same
period without giving pro forma effect to such transaction; provided that for
purposes of determining the Debt to Adjusted Consolidated Cash Flow Ratio of any
entity or Person for purposes of this clause (d) the entity or Person will be
substituted for the Company in the definition of Debt to Adjusted Consolidated
Cash Flow Ratio and the defined terms included therein under Section 4.09
hereof.

Section 5.02.  Successor Corporation Substituted.

     Upon any consolidation or merger, or any sale, assignment, transfer, lease,
conveyance or other disposition of all or substantially all of the assets of the
Company in accordance with Section 5.01 hereof, the successor corporation formed
by such consolidation or into or with which the Company is merged or to which
such sale, assignment, transfer, lease, conveyance or other disposition is made
shall succeed to, and be substituted for (so that from and after the date of
such consolidation, merger, sale, lease, conveyance or other disposition, the
provisions of this Indenture referring to the "Company" shall refer instead to
the successor corporation and not to the Company), and may exercise every right
and

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power of the Company under this Indenture with the same effect as if such
successor Person had been named as the Company herein; provided, however, that
the predecessor Company shall not be relieved from the obligation to pay the
principal of and interest on the Notes except in the case of a sale of all of
the Company's assets that meets the requirements of Section 5.01 hereof.

                                   ARTICLE 6
                             DEFAULTS AND REMEDIES

Section 6.01.  Events of Default.

     Each of the following constitutes an Event of Default:

          (1)  default for 30 days in the payment when due of interest on the
     Notes;

          (2)  default in payment when due of the principal of or premium, if
     any, on the Notes;

          (3)  failure by the Company or any of its Subsidiaries to comply with
     the provisions described under Article 5 hereof or failure by the Company
     to consummate a Change of Control Offer or Asset Sale Offer in accordance
     with the provisions of this Indenture;

          (4)  failure by the Company or any of its Subsidiaries for 30 days
     after notice by the Trustee or the Holders of at least 25% in aggregate
     principal amount of the Notes then outstanding voting as a single class, to
     comply with any of its other agreements in the Indenture or the Notes;

          (5)  default under any mortgage, indenture or instrument under which
     there may be issued or by which there may be secured or evidenced any
     Indebtedness for money borrowed by the Company or any of its Significant
     Subsidiaries (or the payment of which is guaranteed by the Company or any
     of its Significant Subsidiaries) whether such Indebtedness or guarantee now
     exists, or is created after the date of this Indenture, which default:

                    (a)  is caused by a failure to pay principal of or premium,
          if any, or interest on the Indebtedness prior to the expiration of the
          grace period provided in such Indebtedness on the date of the default
          (a "Payment Default"); or

                    (b)  results in the acceleration of the Indebtedness prior
          to its express maturity and, in each case, the principal amount of any
          such Indebtedness, together with the principal amount of any other
          such Indebtedness under which there has been a Payment Default or the
          maturity of which has been so accelerated, aggregates $20.0 million or
          more;

          (6)  failure by the Company or any of its Significant Subsidiaries to
     pay final judgments aggregating in excess of $20.0 million, which judgments
     are not paid, discharged or stayed for a period of 60 days; or

          (7)  the Company or any of its Restricted Subsidiaries pursuant to or
     within the meaning of Bankruptcy Law:

                    (a)  commences a voluntary case,

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                           (b)     consents to the entry of an order for relief
                  against it in an involuntary case,

                           (c)     consents to the appointment of a Custodian of
                  it or for all or substantially all of its property,

                           (d)     makes a general assignment for the benefit of
                  its creditors, or

                           (e)     generally is not paying its debts as they
                  become due; or

                  (8)  a court of competent jurisdiction enters an order or
          decree under any Bankruptcy Law that:

                           (a)     is for relief against the Company or any of
                  its Restricted Subsidiaries in an involuntary case;

                           (b)     appoints a Custodian of the Company or any of
                  its Restricted Subsidiaries or for all or substantially all of
                  the property of the Company or any of its Restricted
                  Subsidiaries; or

                           (c)     orders the liquidation of the Company or any
                  of its Restricted Subsidiaries;

and the order or decree remains unstayed and in effect for 60 consecutive days.

Section 6.02.     Acceleration.

         If any Event of Default occurs and is continuing, the Trustee or the
Holders of at least 25% in principal amount of the then outstanding Notes may
declare all the Notes to be due and payable immediately. Upon any such
declaration, the principal of, and accrued and unpaid interest if any, on such
Notes shall become due and payable immediately. Notwithstanding the foregoing,
if an Event of Default specified in clause (7) or (8) of Section 6.01 hereof
occurs with respect to the Company or any of its Restricted Subsidiaries, all
outstanding Notes shall be due and payable immediately without further action or
notice. The Holders of a majority in aggregate principal amount of the then
outstanding Notes by written notice to the Trustee may on behalf of all of the
Holders rescind an acceleration and its consequences if the rescission would not
conflict with any judgment or decree and if all existing Events of Default
(except nonpayment of principal, interest or premium that has become due solely
because of the acceleration) have been cured or waived.

Section 6.03.     Other Remedies.

         If an Event of Default occurs and is continuing, the Trustee may pursue
any available remedy to collect the payment of principal of, premium, if any,
and interest on the Notes or to enforce the performance of any provision of the
Notes or this Indenture.

         The Trustee may maintain a proceeding even if it does not possess any
of the Notes or does not produce any of them in the proceeding. A delay or
omission by the Trustee or any Holder of a Note in exercising any right or
remedy accruing upon an Event of Default shall not impair the right or remedy or

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<PAGE>

constitute a waiver of or acquiescence in the Event of Default. All remedies are
cumulative to the extent permitted by law.

Section 6.04.     Waiver of Past Defaults.

         Holders of not less than a majority in aggregate principal amount of
the then outstanding Notes by notice to the Trustee may on behalf of the Holders
of all of the Notes waive an existing Default or Event of Default and its
consequences hereunder, except a continuing Default or Event of Default in the
payment of the principal of, premium, if any, or interest on, the Notes
(including in connection with an offer to purchase) (provided, however, that the
Holders of a majority in aggregate principal amount of the then outstanding
Notes may rescind an acceleration and its consequences, including any related
payment default that resulted from such acceleration). Upon any such waiver,
such Default shall cease to exist, and any Event of Default arising therefrom
shall be deemed to have been cured for every purpose of this Indenture; but no
such waiver shall extend to any subsequent or other Default or impair any right
consequent thereon.

Section 6.05.     Control by Majority.

         Holders of a majority in principal amount of the then outstanding Notes
may direct the time, method and place of conducting any proceeding for
exercising any remedy available to the Trustee or exercising any trust or power
conferred on it. However, the Trustee may refuse to follow any direction that
conflicts with law or this Indenture that the Trustee determines may be unduly
prejudicial to the rights of other Holders of Notes or that may involve the
Trustee in personal liability.

Section 6.06.     Limitation on Suits.

         A Holder of a Note may pursue a remedy with respect to this Indenture
or the Notes only if:

         (1)   the Holder of a Note gives to the Trustee written notice of a
continuing Event of Default;

         (2)   the  Holders of at least 25% in principal amount of the then
outstanding Notes make a written request to the Trustee to pursue the remedy;

         (3)   such Holder of a Note or Holders of Notes offer and, if
requested, provide to the Trustee indemnity satisfactory to the Trustee against
any loss, liability or expense;

         (4)   the Trustee does not comply with the request within 60 days after
receipt of the request and the offer and, if requested, the provision of
indemnity; and

         (5)   during such 60-day period the Holders of a majority in principal
amount of the then outstanding Notes do not give the Trustee a direction
inconsistent with the request.

         A Holder of a Note may not use this Indenture to prejudice the rights
of another Holder of a Note or to obtain a preference or priority over another
Holder of a Note.

Section 6.07.     Rights of Holders of Notes to Receive Payment.

         Notwithstanding any other provision of this Indenture, the right of any
Holder of a Note to receive payment of principal of, premium, if any, and
interest on the Note, on or after the respective due

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<PAGE>

dates expressed in the Note (including in connection with an offer to purchase),
or to bring suit for the enforcement of any such payment on or after such
respective dates, shall not be impaired or affected without the consent of such
Holder.

Section 6.08.     Collection Suit by Trustee.

         If an Event of Default specified in Section 6.01(a) or (b) occurs and
is continuing, the Trustee is authorized to recover judgment in its own name and
as trustee of an express trust against the Company for the whole amount of
principal of, premium, if any, and interest remaining unpaid on the Notes and
interest on overdue principal and, to the extent lawful, interest and such
further amount as shall be sufficient to cover the costs and expenses of
collection, including the reasonable compensation, expenses, disbursements and
advances of the Trustee, its agents and counsel.

Section 6.09.     Trustee May File Proofs of Claim.

         The Trustee is authorized to file such proofs of claim and other papers
or documents as may be necessary or advisable in order to have the claims of the
Trustee (including any claim for the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel) and the
Holders of the Notes allowed in any judicial proceedings relative to the Company
(or any other obligor upon the Notes), its creditors or its property and shall
be entitled and empowered to collect, receive and distribute any money or other
property payable or deliverable on any such claims and any Custodian in any such
judicial proceeding is hereby authorized by each Holder to make such payments to
the Trustee, and in the event that the Trustee shall consent to the making of
such payments directly to the Holders, to pay to the Trustee any amount due to
it for the reasonable compensation, expenses, disbursements and advances of the
Trustee, its agents and counsel, and any other amounts due the Trustee under
Section 7.07 hereof. To the extent that the payment of any such compensation,
expenses, disbursements and advances of the Trustee, its agents and counsel, and
any other amounts due the Trustee under Section 7.07 hereof out of the estate in
any such proceeding, shall be denied for any reason, payment of the same shall
be secured by a Lien on, and shall be paid out of, any and all distributions,
dividends, money, securities and other properties that the Holders may be
entitled to receive in such proceeding whether in liquidation or under any plan
of reorganization or arrangement or otherwise. Nothing herein contained shall be
deemed to authorize the Trustee to authorize or consent to or accept or adopt on
behalf of any Holder any plan of reorganization, arrangement, adjustment or
composition affecting the Notes or the rights of any Holder, or to authorize the
Trustee to vote in respect of the claim of any Holder in any such proceeding.

Section 6.10.     Priorities.

         If the Trustee collects any money pursuant to this Article, it shall
pay out the money in the following order:

         First:   to the Trustee, its agents and attorneys for amounts due under
Section 7.07 hereof, including payment of all compensation, expense and
liabilities incurred, and all advances made, by the Trustee and the costs and
expenses of collection;

         Second:    to Holders of Notes for amounts due and unpaid on the Notes
for principal, premium, if any, and interest, ratably, without preference or
priority of any kind, according to the amounts due and payable on the Notes for
principal, premium, if any and interest, respectively; and

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<PAGE>

         Third:   to the Company or to such party as a court of competent
jurisdiction shall direct.

         The Trustee may fix a record date and payment date for any payment to
Holders of Notes pursuant to this Section 6.10.

Section 6.11.     Undertaking for Costs.

         In any suit for the enforcement of any right or remedy under this
Indenture or in any suit against the Trustee for any action taken or omitted by
it as a Trustee, a court in its discretion may require the filing by any party
litigant in the suit of an undertaking to pay the costs of the suit, and the
court in its discretion may assess reasonable costs, including reasonable
attorneys' fees, against any party litigant in the suit, having due regard to
the merits and good faith of the claims or defenses made by the party litigant.
This Section does not apply to a suit by the Trustee, a suit by a Holder of a
Note pursuant to Section 6.07 hereof, or a suit by Holders of more than 10% in
principal amount of the then outstanding Notes.

                                   ARTICLE 7
                                    TRUSTEE

Section 7.01.     Duties of Trustee.

         (a)   If an Event of Default has occurred and is continuing, the
Trustee shall exercise such of the rights and powers vested in it by this
Indenture, and use the same degree of care and skill in its exercise, as a
prudent person would exercise or use under the circumstances in the conduct of
such person's own affairs.

         (b)   Except during the continuance of an Event of Default:

               (i)      the duties of the Trustee shall be determined solely by
         the express provisions of this Indenture and the Trustee need perform
         only those duties that are specifically set forth in this Indenture and
         no others, and no implied covenants or obligations shall be read into
         this Indenture against the Trustee; and

               (ii)     in the absence of bad faith on its part, the Trustee may
         conclusively rely, as to the truth of the statements and the
         correctness of the opinions expressed therein, upon certificates or
         opinions furnished to the Trustee and conforming to the requirements of
         this Indenture. However, the Trustee shall examine the certificates and
         opinions to determine whether or not they conform to the requirements
         of this Indenture.

         (c)   The Trustee may not be relieved from liabilities for its own
negligent action, its own negligent failure to act, or its own willful
misconduct, except that:

               (i)      this paragraph does not limit the effect of paragraph
         (b) of this Section;

               (ii)     the Trustee shall not be liable for any error of
         judgment made in good faith by a Responsible Officer, unless it is
         proved that the Trustee was negligent in ascertaining the pertinent
         facts; and

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<PAGE>

               (iii)    the Trustee shall not be liable with respect to any
         action it takes or omits to take in good faith in accordance with a
         direction received by it pursuant to Section 6.05 hereof.

         (d)   Whether or not therein expressly so provided, every provision of
this Indenture that in any way relates to the Trustee is subject to paragraphs
(a), (b), and (c) of this Section.

         (e)   No provision of this Indenture shall require the Trustee to
expend or risk its own funds or incur any liability. The Trustee shall be under
no obligation to exercise any of its rights and powers under this Indenture at
the request of any Holders, unless such Holder shall have offered to the Trustee
security and indemnity satisfactory to it against any loss, liability or
expense.

         (f)   The Trustee shall not be liable for interest on any money
received by it except as the Trustee may agree in writing with the Company.
Money held in trust by the Trustee need not be segregated from other funds
except to the extent required by law.

Section 7.02.     Rights of Trustee.

         (a)   The Trustee may conclusively rely upon any document believed by
it to be genuine and to have been signed or presented by the proper Person. The
Trustee need not investigate any fact or matter stated in the document.

         (b)   Before the Trustee acts or refrains from acting, it may require
an Officers' Certificate or an Opinion of Counsel or both. The Trustee shall not
be liable for any action it takes or omits to take in good faith in reliance on
such Officers' Certificate or Opinion of Counsel. The Trustee may consult with
counsel and the written and oral advice of such counsel or any Opinion of
Counsel shall be full and complete authorization and protection from liability
in respect of any action taken, suffered or omitted by it hereunder in good
faith and in reliance thereon.

         (c)   The Trustee may act through its attorneys and agents and shall
not be responsible for the misconduct or negligence of any agent appointed with
due care.

         (d)   The Trustee shall not be liable for any action it takes or omits
to take in good faith that it believes to be authorized or within the rights or
powers conferred upon it by this Indenture.

         (e)   Unless otherwise specifically provided in this Indenture, any
demand, request, direction or notice from the Company shall be sufficient if
signed by an Officer of the Company.

         (f)   The Trustee shall be under no obligation to exercise any of the
rights or powers vested in it by this Indenture at the request or direction of
any of the Holders unless such Holders shall have offered to the Trustee
reasonable security or indemnity against the costs, expenses and liabilities
that might be incurred by it in compliance with such request or direction.

Section 7.03.     Individual Rights of Trustee.

         The Trustee in its individual or any other capacity may become the
owner or pledgee of Notes and may otherwise deal with the Company or any
Affiliate of the Company with the same rights it would have if it were not
Trustee. However, in the event that the Trustee acquires any conflicting
interest it must eliminate such conflict within 90 days, apply to the SEC for
permission to continue as trustee or

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<PAGE>

resign. Any Agent may do the same with like rights and duties. The Trustee is
also subject to Sections 7.10 and 7.11 hereof.

Section 7.04.     Trustee's Disclaimer.

         The Trustee shall not be responsible for and makes no representation as
to the validity or adequacy of this Indenture or the Notes, it shall not be
accountable for the Company's use of the proceeds from the Notes or any money
paid to the Company or upon the Company's direction under any provision of this
Indenture, it shall not be responsible for the use or application of any money
received by any Paying Agent other than the Trustee, and it shall not be
responsible for any statement or recital herein or any statement in the Notes or
any other document in connection with the sale of the Notes or pursuant to this
Indenture other than its certificate of authentication.

Section 7.05.     Notice of Defaults.

         If a Default or Event of Default occurs and is continuing and if it is
known to the Trustee, the Trustee shall mail to Holders of Notes a notice of the
Default or Event of Default within 90 days after it occurs. Except in the case
of a Default or Event of Default in payment of principal of, premium, if any, or
interest on any Note, the Trustee may withhold the notice if and so long as a
committee of its Responsible Officers in good faith determines that withholding
the notice is in the interests of the Holders of the Notes.

Section 7.06.     Reports by Trustee to Holders of the Notes.

         Within 60 days after each May 1 beginning with the May 1 following the
date of this Indenture, and for so long as Notes remain outstanding, the Trustee
shall mail to the Holders of the Notes a brief report dated as of such reporting
date that complies with TIA (s) 313(a) (but if no event described in TIA (s)
313(a) has occurred within the twelve months preceding the reporting date, no
report need be transmitted). The Trustee also shall comply with TIA (s) 313(b).
The Trustee shall also transmit by mail all reports as required by TIA (s)
313(c).

         A copy of each report at the time of its mailing to the Holders of
Notes shall be mailed to the Company and filed with the SEC and each stock
exchange on which the Notes are listed in accordance with TIA (S). 313(d). The
Company shall promptly notify the Trustee when the Notes are listed on any stock
exchange.

Section 7.07.     Compensation and Indemnity.

         The Company shall pay to the Trustee from time to time reasonable
compensation for its acceptance of this Indenture and services hereunder. The
Trustee's compensation shall not be limited by any law on compensation of a
trustee of an express trust. The Company shall reimburse the Trustee promptly
upon request for all reasonable disbursements, advances and expenses incurred or
made by it in addition to the compensation for its services. Such expenses shall
include the reasonable compensation, disbursements and expenses of the Trustee's
agents and counsel.

         The Company shall indemnify the Trustee against any and all losses,
liabilities or expenses incurred by it arising out of or in connection with the
acceptance or administration of its duties under this Indenture, including the
costs and expenses of enforcing this Indenture against the Company (including

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<PAGE>

this Section 7.07) and defending itself against any claim (whether asserted by
the Company or any Holder or any other person) or liability in connection with
the exercise or performance of any of its powers or duties hereunder, except to
the extent any such loss, liability or expense may be attributable to its
negligence or bad faith. The Trustee shall notify the Company promptly of any
claim for which it may seek indemnity. Failure by the Trustee to so notify the
Company shall not relieve the Company of its obligations hereunder. The Company
shall defend the claim and the Trustee shall cooperate in the defense. The
Trustee may have separate counsel and the Company shall pay the reasonable fees
and expenses of such counsel. The Company need not pay for any settlement made
without its consent, which consent shall not be unreasonably withheld.

         The obligations of the Company under this Section 7.07 shall survive
the satisfaction and discharge of this Indenture.

         To secure the Company's payment obligations in this Section, the
Trustee shall have a Lien prior to the Notes on all money or property held or
collected by the Trustee, except that held in trust to pay principal and
interest on particular Notes. Such Lien shall survive the satisfaction and
discharge of this Indenture.

         When the Trustee incurs expenses or renders services after an Event of
Default specified in Section 6.01(g) or (h) hereof occurs, the expenses and the
compensation for the services (including the fees and expenses of its agents and
counsel) are intended to constitute expenses of administration under any
Bankruptcy Law.

         The Trustee shall comply with the provisions of TIA ss. 313(b)(2) to
the extent applicable.

Section 7.08.     Replacement of Trustee.

         A resignation or removal of the Trustee and appointment of a successor
Trustee shall become effective only upon the successor Trustee's acceptance of
appointment as provided in this Section.

         The Trustee may resign in writing at any time and be discharged from
the trust hereby created by so notifying the Company. The Holders of a majority
in principal amount of the then outstanding Notes may remove the Trustee by so
notifying the Trustee and the Company in writing. The Company may remove the
Trustee if:

         (a)   the Trustee fails to comply with Section 7.10 hereof;

         (b)   the Trustee is adjudged a bankrupt or an insolvent or an order
for relief is entered with respect to the Trustee under any Bankruptcy Law;

         (c)   a Custodian or public officer takes charge of the Trustee or its
property; or

         (d)   the Trustee becomes incapable of acting.

         If the Trustee resigns or is removed or if a vacancy exists in the
office of Trustee for any reason, the Company shall promptly appoint a successor
Trustee. Within one year after the successor Trustee takes office, the Holders
of a majority in principal amount of the then outstanding Notes may appoint a
successor Trustee to replace the successor Trustee appointed by the Company.

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<PAGE>

         If a successor Trustee does not take office within 60 days after the
retiring Trustee resigns or is removed, the retiring Trustee, the Company, or
the Holders of at least 10% in principal amount of the then outstanding Notes
may petition any court of competent jurisdiction for the appointment of a
successor Trustee.

         If the Trustee, after written request by any Holder who has been a
Holder for at least six months, fails to comply with Section 7.10, such Holder
may petition any court of competent jurisdiction for the removal of the Trustee
and the appointment of a successor Trustee.

         A successor Trustee shall deliver a written acceptance of its
appointment to the retiring Trustee and to the Company. Thereupon, the
resignation or removal of the retiring Trustee shall become effective, and the
successor Trustee shall have all the rights, powers and duties of the Trustee
under this Indenture. The successor Trustee shall mail a notice of its
succession to Holders. The retiring Trustee shall promptly transfer all property
held by it as Trustee to the successor Trustee, provided all sums owing to the
Trustee hereunder have been paid and subject to the Lien provided for in Section
7.07 hereof. Notwithstanding replacement of the Trustee pursuant to this Section
7.08, the Company's obligations under Section 7.07 hereof shall continue for the
benefit of the retiring Trustee.

Section 7.09.     Successor Trustee by Merger, etc.

         If the Trustee consolidates, merges or converts into, or transfers all
or substantially all of its corporate trust business to, another corporation,
the successor corporation without any further act shall be the successor
Trustee.

Section 7.10.     Eligibility; Disqualification.

         There shall at all times be a Trustee hereunder that is a corporation
organized and doing business under the laws of the United States of America or
of any state thereof that is authorized under such laws to exercise corporate
trustee power, that is subject to supervision or examination by federal or state
authorities and that has a combined capital and surplus of at least $75 million
as set forth in its most recent published annual report of condition.

         This Indenture shall always have a Trustee who satisfies the
requirements of TIA (s) 310(a)(1), (2) and (5). The Trustee is subject to TIA
(s) 310(b).

Section 7.11.     Preferential Collection of Claims Against Company.

         The Trustee is subject to TIA (s) 311(a), excluding any creditor
relationship listed in TIA (s) 311(b). A Trustee who has resigned or been
removed shall be subject to TIA (s) 311(a) to the extent indicated therein.

                                   ARTICLE 8
                   LEGAL DEFEASANCE AND COVENANT DEFEASANCE

Section 8.01.     Option to Effect Legal Defeasance or Covenant Defeasance.

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<PAGE>

         The Company may, at the option of its Board of Directors evidenced by a
resolution set forth in an Officers' Certificate, at any time, elect to have
either Section 8.02 or 8.03 hereof be applied to all outstanding Notes upon
compliance with the conditions set forth below in this Article Eight.

Section 8.02.     Legal Defeasance and Discharge.

         Upon the Company's exercise under Section 8.01 hereof of the option
applicable to this Section 8.02, the Company shall, subject to the satisfaction
of the conditions set forth in Section 8.04 hereof, be deemed to have been
discharged from its obligations with respect to all outstanding Notes on the
date the conditions set forth below are satisfied (hereinafter, "Legal
Defeasance"). For this purpose, Legal Defeasance means that the Company shall be
deemed to have paid and discharged the entire Indebtedness represented by the
outstanding Notes, which shall thereafter be deemed to be "outstanding" only for
the purposes of Section 8.05 hereof and the other Sections of this Indenture
referred to in (1) and (2) below, and to have satisfied all its other
obligations under such Notes and this Indenture (and the Trustee, on demand of
and at the expense of the Company, shall execute proper instruments
acknowledging the same), except for the following provisions which shall survive
until otherwise terminated or discharged hereunder:

         (1)   the rights of Holders of outstanding Notes to receive solely from
the trust fund described in Section 8.04 hereof, and as more fully set forth in
such Section, payments in respect of the principal of, premium, if any, and
interest on such Notes when such payments are due;

         (2)   the Company's obligations with respect to such Notes under
Article 2 and Section 4.02 hereof;

         (3)   the rights, powers, trusts, duties and immunities of the Trustee
hereunder and the Company's obligations in connection therewith; and

         (4)   this Article Eight.

         Subject to compliance with this Article Eight, the Company may exercise
its option under this Section 8.02 notwithstanding the prior exercise of its
option under Section 8.03 hereof.

Section 8.03.     Covenant Defeasance.

         Upon the Company's exercise under Section 8.01 hereof of the option
applicable to this Section 8.03, the Company shall, subject to the satisfaction
of the conditions set forth in Section 8.04 hereof, be released from its
obligations under the covenants contained in Sections 4.07, 4.08, 4.09, 4.10,
4.11, 4.12, 4.13, 4.15, 4.16, 4.17 and 4.18 hereof and clause (4) of Section
5.01 hereof with respect to the outstanding Notes on and after the date the
conditions set forth in Section 8.04 are satisfied (hereinafter, "Covenant
Defeasance"), and the Notes shall thereafter be deemed not "outstanding" for the
purposes of any direction, waiver, consent or declaration or act of Holders (and
the consequences of any thereof) in connection with such covenants, but shall
continue to be deemed "outstanding" for all other purposes hereunder (it being
understood that such Notes shall not be deemed outstanding for accounting
purposes). For this purpose, Covenant Defeasance means that, with respect to the
outstanding Notes, the Company may omit to comply with and shall have no
liability in respect of any term, condition or limitation set forth in any such
covenant, whether directly or indirectly, by reason of any reference elsewhere
herein to any such covenant or by reason of any reference in any such covenant
to any other

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<PAGE>

provision herein or in any other document and such omission to comply shall not
constitute a Default or an Event of Default under Section 6.01 hereof, but,
except as specified above, the remainder of this Indenture and such Notes shall
be unaffected thereby. In addition, upon the Company's exercise under Section
8.01 hereof of the option applicable to this Section 8.03 hereof, subject to the
satisfaction of the conditions set forth in Section 8.04 hereof, Sections
6.01(3) through 6.01(6) hereof shall not constitute Events of Default.

Section 8.04.     Conditions to Legal or Covenant Defeasance.

         The following shall be the conditions to the application of either
Section 8.02 or 8.03 hereof to the outstanding Notes:

         In order to exercise either Legal Defeasance or Covenant Defeasance:

         (1)   the Company must irrevocably deposit with the Trustee, in trust,
for the benefit of the Holders, cash in United States dollars, non-callable
Government Securities, or a combination thereof, in such amounts as will be
sufficient, in the opinion of a nationally recognized firm of independent public
accountants, to pay the principal of, premium, if any, and interest on the
outstanding Notes on the stated date for payment thereof or on the applicable
redemption date, as the case may be;

         (2)   in the case of an election under Section 8.02 hereof, the Company
shall have delivered to the Trustee an Opinion of Counsel in the United States
reasonably acceptable to the Trustee confirming that:

               (a)  the Company has received from, or there has been published
         by, the Internal Revenue Service a ruling; or

               (b)  since the date of this Indenture, there has been a change in
         the applicable federal income tax law, in either case to the effect
         that, and based thereon such Opinion of Counsel shall confirm that, the
         Holders of the outstanding Notes will not recognize income, gain or
         loss for federal income tax purposes as a result of such Legal
         Defeasance and will be subject to federal income tax on the same
         amounts, in the same manner and at the same times as would have been
         the case if such Legal Defeasance had not occurred;

         (3)   in the case of an election under Section 8.03 hereof, the Company
shall have delivered to the Trustee an Opinion of Counsel in the United States
reasonably acceptable to the Trustee confirming that the Holders of the
outstanding Notes will not recognize income, gain or loss for federal income tax
purposes as a result of such Covenant Defeasance and will be subject to federal
income tax on the same amounts, in the same manner and at the same times as
would have been the case if such Covenant Defeasance had not occurred;

         (4)   no Default or Event of Default shall have occurred and be
continuing either:

               (a)  on the date of such deposit (other than a Default or Event
         of Default resulting from the borrowing of funds to be applied to such
         deposit); or

               (b)  insofar as Sections 6.01(7) or 6.01(8) hereof are concerned,
         at any time in the period ending on the 91st day after the date of
         deposit;

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         (5)  such Legal Defeasance or Covenant Defeasance shall not result in a
breach or violation of, or constitute a default under, any material agreement or
instrument (other than this Indenture) to which the Company or any of its
Restricted Subsidiaries is a party or by which the Company or any of its
Restricted Subsidiaries is bound;

         (6)  the Company shall have delivered to the Trustee an Opinion of
Counsel to the effect that on the 91st day following the deposit, the trust
funds will not be subject to the effect of any applicable bankruptcy,
insolvency, reorganization or similar laws affecting creditors' rights
generally;

         (7)  the Company shall have delivered to the Trustee an Officers'
Certificate stating that the deposit was not made by the Company with the intent
of preferring the Holders over any other creditors of the Company or with the
intent of defeating, hindering, delaying or defrauding any other creditors of
the Company or others; and

         (8)  the Company shall have delivered to the Trustee an Officers'
Certificate and an Opinion of Counsel, each stating that all conditions
precedent provided for or relating to the Legal Defeasance or the Covenant
Defeasance have been complied with.

Section 8.05. Deposited Money and Government Securities to be Held in Trust;
Other Miscellaneous Provisions.

         Subject to Section 8.06 hereof, all money and non-callable Government
Securities (including the proceeds thereof) deposited with the Trustee (or other
qualifying trustee, collectively for purposes of this Section 8.05, the
"Trustee") pursuant to Section 8.04 hereof in respect of the outstanding Notes
shall be held in trust and applied by the Trustee, in accordance with the
provisions of such Notes and this Indenture, to the payment, either directly or
through any Paying Agent (including the Company acting as Paying Agent) as the
Trustee may determine, to the Holders of such Notes of all sums due and to
become due thereon in respect of principal, premium, if any, and interest, but
such money need not be segregated from other funds except to the extent required
by law.

         The Company shall pay and indemnify the Trustee against any tax, fee or
other charge imposed on or assessed against the cash or non-callable Government
Securities deposited pursuant to Section 8.04 hereof or the principal and
interest received in respect thereof other than any such tax, fee or other
charge which by law is for the account of the Holders of the outstanding Notes.

         Anything in this Article Eight to the contrary notwithstanding, the
Trustee shall deliver or pay to the Company from time to time upon the request
of the Company any money or non-callable Government Securities held by it as
provided in Section 8.04 hereof which, in the opinion of a nationally recognized
firm of independent public accountants expressed in a written certification
thereof delivered to the Trustee (which may be the opinion delivered under
Section 8.04(a) hereof), are in excess of the amount thereof that would then be
required to be deposited to effect an equivalent Legal Defeasance or Covenant
Defeasance.

Section 8.06. Repayment to Company.

         Any money deposited with the Trustee or any Paying Agent, or then held
by the Company, in trust for the payment of the principal of, premium, if any,
or interest on any Note and remaining unclaimed for two years after such
principal, and premium, if any, or interest has become due and

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payable shall be paid to the Company on its request or (if then held by the
Company) shall be discharged from such trust; and the Holder of such Note shall
thereafter look only to the Company for payment thereof, and all liability of
the Trustee or such Paying Agent with respect to such trust money, and all
liability of the Company as trustee thereof, shall thereupon cease; provided,
however, that the Trustee or such Paying Agent, before being required to make
any such repayment, may at the expense of the Company cause to be published
once, in the New York Times and The Wall Street Journal (national edition),
notice that such money remains unclaimed and that, after a date specified
therein, which shall not be less than 30 days from the date of such notification
or publication, any unclaimed balance of such money then remaining will be
repaid to the Company.

Section 8.07. Reinstatement.

         If the Trustee or Paying Agent is unable to apply any United States
dollars or non-callable Government Securities in accordance with Section 8.02 or
8.03 hereof, as the case may be, by reason of any order or judgment of any court
or governmental authority enjoining, restraining or otherwise prohibiting such
application, then the Company's obligations under this Indenture and the Notes
shall be revived and reinstated as though no deposit had occurred pursuant to
Section 8.02 or 8.03 hereof until such time as the Trustee or Paying Agent is
permitted to apply all such money in accordance with Section 8.02 or 8.03
hereof, as the case may be; provided, however, that, if the Company makes any
payment of principal of, premium, if any, or interest on any Note following the
reinstatement of its obligations, the Company shall be subrogated to the rights
of the Holders of such Notes to receive such payment from the money held by the
Trustee or Paying Agent.

                                   ARTICLE 9
                       AMENDMENT, SUPPLEMENT AND WAIVER

Section 9.01. Without Consent of Holders of Notes.

         Notwithstanding Section 9.02 of this Indenture, the Company and the
Trustee may amend or supplement this Indenture or the Notes without the consent
of any Holder of Notes:

         (1)  to cure any ambiguity, defect or inconsistency;

         (2)  to provide for uncertificated Notes in addition to or in place of
certificated Notes or to alter the provisions of Article 2 hereof (including the
related definitions) in a manner that does not materially adversely affect any
Holder;

         (3)  to provide for the assumption of the Company's obligations to the
Holders of the Notes by a successor to the Company pursuant to Article 5 hereof;

         (4)  to make any change that would provide any additional rights or
benefits to the Holders of the Notes or that does not adversely affect the legal
rights hereunder of any Holder of Notes;

         (5)  to comply with requirements of the SEC in order to effect or
maintain the qualification of this Indenture under the TIA;

         (6)  to provide for the issuance of the Additional Notes in accordance
with the limitations set forth in this Indenture as of the date hereof.

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         Upon the request of the Company accompanied by a resolution of its
Board of Directors authorizing the execution of any such amended or supplemental
Indenture, and upon receipt by the Trustee of the documents described in Section
7.02 hereof, the Trustee shall join with the Company in the execution of any
amended or supplemental Indenture authorized or permitted by the terms of this
Indenture and to make any further appropriate agreements and stipulations that
may be therein contained, but the Trustee shall not be obligated to enter into
such amended or supplemental Indenture that affects its own rights, duties or
immunities under this Indenture or otherwise.

Section 9.02. With Consent of Holders of Notes.

         Except as provided below in this Section 9.02, the Company and the
Trustee may amend or supplement this Indenture (including Section 3.09, 4.10 and
4.15 hereof) and the Notes with the consent of the Holders of at least a
majority in principal amount of the Notes then outstanding, voting as a single
class, (including, without limitation, consents obtained in connection with a
tender offer or exchange offer for, or purchase of, the Notes), and, subject to
Sections 6.04 and 6.07 hereof, any existing Default or Event of Default (other
than a Default or Event of Default in the payment of the principal of, premium,
if any, or interest on the Notes, except a payment default resulting from an
acceleration that has been rescinded) or compliance with any provision of this
Indenture or the Notes may be waived with the consent of the Holders of a
majority in principal amount of the then outstanding Notes, voting as a single
class, (including consents obtained in connection with a tender offer or
exchange offer for, or purchase of, the Notes). Section 2.08 hereof shall
determine which Notes are considered to be "outstanding" for purposes of this
Section 9.02.

         Upon the request of the Company accompanied by a resolution of its
Board of Directors authorizing the execution of any such amended or supplemental
Indenture, and upon the filing with the Trustee of evidence satisfactory to the
Trustee of the consent of the Holders of Notes as aforesaid, and upon receipt by
the Trustee of the documents described in Section 7.02 hereof, the Trustee shall
join with the Company in the execution of such amended or supplemental Indenture
unless such amended or supplemental Indenture directly affects the Trustee's own
rights, duties or immunities under this Indenture or otherwise, in which case
the Trustee may in its discretion, but shall not be obligated to, enter into
such amended or supplemental Indenture.

         It shall not be necessary for the consent of the Holders of Notes under
this Section 9.02 to approve the particular form of any proposed amendment or
waiver, but it shall be sufficient if such consent approves the substance
thereof.

         After an amendment, supplement or waiver under this Section becomes
effective, the Company shall mail to the Holders of Notes affected thereby a
notice briefly describing the amendment, supplement or waiver. Any failure of
the Company to mail such notice, or any defect therein, shall not, however, in
any way impair or affect the validity of any such amended or supplemental
Indenture or waiver. Subject to Sections 6.04 and 6.07 hereof, the Holders of a
majority in aggregate principal amount of the Notes then outstanding, voting as
a single class, may waive compliance in a particular instance by the Company
with any provision of this Indenture or the Notes. However, without the consent
of each Holder affected, an amendment or waiver under this Section 9.02 may not
(with respect to any Notes held by a non-consenting Holder):

         (1)  reduce the principal amount of Notes whose Holders must consent to
an amendment, supplement or waiver;

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<PAGE>

         (2)  reduce the principal of or change the fixed maturity of any Note
or alter or waive any of the provisions with respect to the redemption of the
Notes, except as provided above with respect to Sections 3.09, 4.10 and 4.15
hereof;

         (3)  reduce the rate of or change the time for payment of interest,
including default interest, on any Note;

         (4)  waive a Default or Event of Default in the payment of principal of
or premium, if any, or interest on the Notes (except a rescission of
acceleration of the Notes by the Holders of at least a majority in aggregate
principal amount of the then outstanding Notes and a waiver of the payment
default that resulted from such acceleration);

         (5)  make any Note payable in money other than that stated in the
Notes;

         (6)  make any change in the provisions of this Indenture relating to
waivers of past Defaults or the rights of Holders of Notes to receive payments
of principal of, or premium, if any, or interest on the Notes;

         (7)  waive a redemption payment (but not any payment pursuant to
Sections 3.09, 4.10 or 4.15 hereof) with respect to any Note;

         (8)  except as provided under Article Eight hereof or in accordance
with the terms of any Note Guarantee, release any Guarantor from any of its
obligations under its Note Guarantee or make any change in a Note Guarantee that
would adversely affect the Holders of the Notes; or

         (9)  make any change in Section 6.04 or 6.07 hereof or in the foregoing
amendment and waiver provisions.

Section 9.03. Compliance with Trust Indenture Act.

         Every amendment or supplement to this Indenture or the Notes shall be
set forth in a amended or supplemental Indenture that complies with the TIA as
then in effect.

Section 9.04. Revocation and Effect of Consents.

         Until an amendment, supplement or waiver becomes effective, a consent
to it by a Holder of a Note is a continuing consent by the Holder of a Note and
every subsequent Holder of a Note or portion of a Note that evidences the same
debt as the consenting Holder's Note, even if notation of the consent is not
made on any Note. However, any such Holder of a Note or subsequent Holder of a
Note may revoke the consent as to its Note if the Trustee receives written
notice of revocation before the date the waiver, supplement or amendment becomes
effective. An amendment, supplement or waiver becomes effective in accordance
with its terms and thereafter binds every Holder.

Section 9.05. Notation on or Exchange of Notes.

         The Trustee may place an appropriate notation about an amendment,
supplement or waiver on any Note thereafter authenticated. The Company in
exchange for all Notes may issue and the Trustee shall, upon receipt of an
Authentication Order, authenticate new Notes that reflect the amendment,
supplement or waiver.

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<PAGE>

         Failure to make the appropriate notation or issue a new Note shall not
affect the validity and effect of such amendment, supplement or waiver.

Section 9.06.   Trustee to Sign Amendments, etc.

         The Trustee shall sign any amended or supplemental Indenture authorized
pursuant to this Article Nine if the amendment or supplement does not adversely
affect the rights, duties, liabilities or immunities of the Trustee. The Company
may not sign an amendment or supplemental Indenture until the Board of Directors
approves it. In executing any amended or supplemental indenture, the Trustee
shall be entitled to receive and (subject to Section 7.01 hereof) shall be fully
protected in relying upon, in addition to the documents required by Section
11.04 hereof, an Officer's Certificate and an Opinion of Counsel stating that
the execution of such amended or supplemental indenture is authorized or
permitted by this Indenture.

                                  ARTICLE 10
                                NOTE GUARANTEES

Section 10.01.  Guarantee.

         The provisions of this Article 10 shall apply only to those
Subsidiaries of the Company, if any, that execute one or more supplemental
indentures to this Indenture in the form of Exhibit E to this Indenture in
compliance with the requirements of Section 4.18 of this Indenture.

         Subject to this Article 10, each of the Guarantors hereby, jointly and
severally, unconditionally guarantees to each Holder of a Note authenticated and
delivered by the Trustee and to the Trustee and its successors and assigns,
irrespective of the validity and enforceability of this Indenture, the Notes or
the obligations of the Company hereunder or thereunder, that: (a) the principal
of and interest on the Notes will be promptly paid in full when due, whether at
maturity, by acceleration, redemption or otherwise, and interest on the overdue
principal of and interest on the Notes, if any, if lawful, and all other
obligations of the Company to the Holders or the Trustee hereunder or thereunder
will be promptly paid in full or performed, all in accordance with the terms
hereof and thereof; and (b) in case of any extension of time of payment or
renewal of any Notes or any of such other obligations, that same will be
promptly paid in full when due or performed in accordance with the terms of the
extension or renewal, whether at stated maturity, by acceleration or otherwise.
Failing payment when due of any amount so guaranteed or any performance so
guaranteed for whatever reason, the Guarantors shall be jointly and severally
obligated to pay the same immediately. Each Guarantor agrees that this is a
guarantee of payment and not a guarantee of collection.

         The Guarantors hereby agree that their obligations hereunder shall be
unconditional, irrespective of the validity, regularity or enforceability of the
Notes or this Indenture, the absence of any action to enforce the same, any
waiver or consent by any Holder of the Notes with respect to any provisions
hereof or thereof, the recovery of any judgment against the Company, any action
to enforce the same or any other circumstance which might otherwise constitute a
legal or equitable discharge or defense of a guarantor. Each Guarantor hereby
waives diligence, presentment, demand of payment, filing of claims with a court
in the event of insolvency or bankruptcy of the Company, any right to require a
proceeding first against the Company, protest, notice and all demands whatsoever
and covenant that this Note Guarantee shall not be discharged except by complete
performance of the obligations contained in the Notes and this Indenture.

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<PAGE>

         If any Holder or the Trustee is required by any court or otherwise to
return to the Company, the Guarantors or any Custodian, trustee, liquidator or
other similar official acting in relation to either the Company or the
Guarantors, any amount paid by either to the Trustee or such Holder, this Note
Guarantee, to the extent theretofore discharged, shall be reinstated in full
force and effect.

         Each Guarantor agrees that it shall not be entitled to any right of
subrogation in relation to the Holders in respect of any obligations guaranteed
hereby until payment in full of all obligations guaranteed hereby. Each
Guarantor further agrees that, as between the Guarantors, on the one hand, and
the Holders and the Trustee, on the other hand, (x) the maturity of the
obligations guaranteed hereby may be accelerated as provided in Article 6 hereof
for the purposes of this Note Guarantee, notwithstanding any stay, injunction or
other prohibition preventing such acceleration in respect of the obligations
guaranteed hereby, and (y) in the event of any declaration of acceleration of
such obligations as provided in Article 6 hereof, such obligations (whether or
not due and payable) shall forthwith become due and payable by the Guarantors
for the purpose of this Note Guarantee. The Guarantors shall have the right to
seek contribution from any non-paying Guarantor so long as the exercise of such
right does not impair the rights of the Holders under the Guarantee.

Section 10.02.  Limitation on Guarantor Liability.

         Each Guarantor, and by its acceptance of Notes, each Holder, hereby
confirms that it is the intention of all such parties that the Note Guarantee of
such Guarantor not constitute a fraudulent transfer or conveyance for purposes
of Bankruptcy Law, the Uniform Fraudulent Conveyance Act, the Uniform Fraudulent
Transfer Act or any similar federal or state law to the extent applicable to any
Note Guarantee. To effectuate the foregoing intention, the Trustee, the Holders
and the Guarantors hereby irrevocably agree that the obligations of such
Guarantor will, after giving effect to such maximum amount and all other
contingent and fixed liabilities of such Guarantor that are relevant under such
laws, and after giving effect to any collections from, rights to receive
contribution from or payments made by or on behalf of any other Guarantor in
respect of the obligations of such other Guarantor under this Article 10, result
in the obligations of such Guarantor under its Note Guarantee not constituting a
fraudulent transfer or conveyance.

Section 10.03.  Execution and Delivery of Note Guarantee.

         To evidence its Note Guarantee set forth in Section 10.01, each
Guarantor hereby agrees that a notation of such Note Guarantee substantially in
the form included in Exhibit F shall be endorsed by an Officer of such Guarantor
on each Note authenticated and delivered by the Trustee and that this Indenture
shall be executed on behalf of such Guarantor by its President or one of its
Vice Presidents.

         Each Guarantor hereby agrees that its Note Guarantee set forth in
Section 10.01 shall remain in full force and effect notwithstanding any failure
to endorse on each Note a notation of such Note Guarantee.

         If an Officer whose signature is on this Indenture or on the Note
Guarantee no longer holds that office at the time the Trustee authenticates the
Note on which a Note Guarantee is endorsed, the Note Guarantee shall be valid
nevertheless.

         The delivery of any Note by the Trustee, after the authentication
thereof hereunder, shall constitute due delivery of the Note Guarantee set forth
in this Indenture on behalf of the Guarantors.

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<PAGE>

         In the event that the Company creates or acquires any new Subsidiaries
subsequent to the date of this Indenture, if required by Section 4.18 hereof,
the Company shall cause such Subsidiaries to execute supplemental indentures to
this Indenture and Note Guarantees in accordance with Section 4.18 hereof and
this Article 10, to the extent applicable.

Section 10.04.  Guarantors May Consolidate, etc., on Certain Terms.

         Except as otherwise provided in Section 10.05, no Guarantor may
consolidate with or merge with or into (whether or not such Guarantor is the
surviving Person) another Person whether or not affiliated with such Guarantor
unless:

         (a)  subject to Section 10.05 hereof, the Person formed by or surviving
any such consolidation or merger (if other than a Guarantor or the Company)
unconditionally assumes all the obligations of such Guarantor, pursuant to a
supplemental indenture in form and substance reasonably satisfactory to the
Trustee, under the Notes, the Indenture and the Note Guarantee on the terms set
forth herein or therein; and

         (b)  immediately after giving effect to such transaction, no Default or
Event of Default exists.

         In case of any such consolidation, merger, sale or conveyance and upon
the assumption by the successor Person, by supplemental indenture, executed and
delivered to the Trustee and satisfactory in form to the Trustee, of the Note
Guarantee endorsed upon the Notes and the due and punctual performance of all of
the covenants and conditions of this Indenture to be performed by the Guarantor,
such successor Person shall succeed to and be substituted for the Guarantor with
the same effect as if it had been named herein as a Guarantor. Such successor
Person thereupon may cause to be signed any or all of the Note Guarantees to be
endorsed upon all of the Notes issuable hereunder which theretofore shall not
have been signed by the Company and delivered to the Trustee. All the Note
Guarantees so issued shall in all respects have the same legal rank and benefit
under this Indenture as the Note Guarantees theretofore and thereafter issued in
accordance with the terms of this Indenture as though all of such Note
Guarantees had been issued at the date of the execution hereof.

         Except as set forth in Articles 4 and 5 hereof, and notwithstanding
clauses (a) and (b) above, nothing contained in this Indenture or in any of the
Notes shall prevent any consolidation or merger of a Guarantor with or into the
Company or another Guarantor, or shall prevent any sale or conveyance of the
property of a Guarantor as an entirety or substantially as an entirety to the
Company or another Guarantor.

Section 10.05.  Releases Following Sale of Assets.

         In the event of a sale or other disposition of all of the assets of any
Guarantor, by way of merger, consolidation or otherwise, or a sale or other
disposition of all to the capital stock of any Guarantor, in each case to a
Person that is not (either before or after giving effect to such transactions) a
Subsidiary of the Company, then such Guarantor (in the event of a sale or other
disposition, by way of merger, consolidation or otherwise, of all of the capital
stock of such Guarantor) or the corporation acquiring the property (in the event
of a sale or other disposition of all or substantially all of the assets of such
Guarantor) will be released and relieved of any obligations under its Note
Guarantee; provided that the Net Proceeds of such sale or other disposition are
applied in accordance with the applicable provisions of this Indenture,
including without limitation Section 4.10 hereof. Upon delivery by the Company
to the

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Trustee of an Officers' Certificate and an Opinion of Counsel to the effect that
such sale or other disposition was made by the Company in accordance with the
provisions of this Indenture, including without limitation Section 4.10 hereof,
the Trustee shall execute any documents reasonably required in order to evidence
the release of any Guarantor from its obligations under its Note Guarantee.

         Any Guarantor not released from its obligations under its Note
Guarantee shall remain liable for the full amount of principal of and interest
on the Notes and for the other obligations of any Guarantor under this Indenture
as provided in this Article 10.



                                  ARTICLE 11
                                 MISCELLANEOUS

Section 11.01.  Trust Indenture Act Controls.

         If any provision of this Indenture limits, qualifies or conflicts with
the duties imposed by TIA (S).318(c), the imposed duties shall control.

Section 11.02.  Notices.

         Any notice or communication by the Company or the Trustee to the others
is duly given if in writing and delivered in Person or mailed by first class
mail (registered or certified, return receipt requested), telex, telecopier or
overnight air courier guaranteeing next day delivery, to the others' address:

                If to the Company:

                Crown Castle International Corp.
                510 Bering Drive, Suite 500
                Houston, Texas  77057
                Telecopier No.: (713) 570-3150
                Attention:  Chief Financial Officer

                With a copy to:

                Cravath, Swaine & Moore
                825 Eighth Avenue
                New York, New York  10019
                Telecopier No.: (212) 474-3700
                Attention:  Stephen L. Burns, Esq.

                If to the Trustee:

                The Bank of New York
                101 Barclay Street
                New York, New York  10286
                Telecopier No.: (212) 815 5915
                Attention:  Corporate Trust Administration

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<PAGE>

         The Company or the Trustee, by notice to the others, may designate
additional or different addresses for subsequent notices or communications.

         All notices and communications (other than those sent to Holders) shall
be deemed to have been duly given: at the time delivered by hand, if personally
delivered; five Business Days after being deposited in the mail, postage
prepaid, if mailed; when answered back, if telexed; when receipt acknowledged,
if telecopied; and the next Business Day after timely delivery to the courier,
if sent by overnight air courier guaranteeing next day delivery.

         Any notice or communication to a Holder shall be mailed by first class
mail, certified or registered, return receipt requested, or by overnight air
courier guaranteeing next day delivery to its address shown on the register kept
by the Registrar. Any notice or communication shall also be so mailed to any
Person described in TIA (S). 313(c), to the extent required by the TIA. Failure
to mail a notice or communication to a Holder or any defect in it shall not
affect its sufficiency with respect to other Holders.

         If a notice or communication is mailed in the manner provided above
within the time prescribed, it is duly given, whether or not the addressee
receives it.

         If the Company mails a notice or communication to Holders, it shall
mail a copy to the Trustee and each Agent at the same time.

Section 11.03.  Communication by Holders of Notes with Other Holders of Notes.

         Holders may communicate pursuant to TIA (S). 312(b) with other Holders
with respect to their rights under this Indenture or the Notes. The Company, the
Trustee, the Registrar and anyone else shall have the protection of TIA (S).
312(c).

Section 11.04.  Certificate and Opinion as to Conditions Precedent.

         Upon any request or application by the Company to the Trustee to take
any action under this Indenture, the Company shall furnish to the Trustee:

         (a) an Officers' Certificate in form and substance reasonably
satisfactory to the Trustee (which shall include the statements set forth in
Section 11.05 hereof) stating that, in the opinion of the signers, all
conditions precedent and covenants, if any, provided for in this Indenture
relating to the proposed action have been satisfied; and

         (b) an Opinion of Counsel in form and substance reasonably satisfactory
to the Trustee (which shall include the statements set forth in Section 11.05
hereof) stating that, in the opinion of such counsel, all such conditions
precedent and covenants have been satisfied.

Section 11.05.  Statements Required in Certificate or Opinion.

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<PAGE>

         Each certificate or opinion with respect to compliance with a condition
or covenant provided for in this Indenture (other than a certificate provided
pursuant to TIA (S). 314(a)(4)) shall comply with the provisions of TIA (S).
314(e) and shall include:

         (a) a statement that the Person making such certificate or opinion has
read such covenant or condition;

         (b) a brief statement as to the nature and scope of the examination or
investigation upon which the statements or opinions contained in such
certificate or opinion are based;

         (c) a statement that, in the opinion of such Person, he or she has made
such examination or investigation as is necessary to enable him to express an
informed opinion as to whether or not such covenant or condition has been
satisfied; and

         (d) a statement as to whether or not, in the opinion of such Person,
such condition or covenant has been satisfied.

Section 11.06.  Rules by Trustee and Agents.

         The Trustee may make reasonable rules for action by or at a meeting of
Holders. The Registrar or Paying Agent may make reasonable rules and set
reasonable requirements for its functions; provided that no such rule shall
conflict with the terms of this Indenture or the TIA.

Section 11.07.  No Personal Liability of Directors, Officers, Employees and
Stockholders.

         No past, present or future director, officer, employee, incorporator or
stockholder of the Company, as such, shall have any liability for any
obligations of the Company under the Notes, this Indenture or for any claim
based on, in respect of, or by reason of, such obligations or their creation.
Each Holder by accepting a Note waives and releases all such liability. The
waiver and release are part of the consideration for issuance of the Notes.

Section 11.08.  Governing Law.

         THE INTERNAL LAW OF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO
CONSTRUE THIS INDENTURE AND THE NOTES WITHOUT GIVING EFFECT TO APPLICABLE
PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF
ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

Section 11.09.  No Adverse Interpretation of Other Agreements.

         This Indenture may not be used to interpret any other indenture, loan
or debt agreement of the Company or its Subsidiaries or of any other Person. Any
such indenture, loan or debt agreement may not be used to interpret this
Indenture.

Section 11.10.  Successors.

                                       80
<PAGE>

         All agreements of the Company in this Indenture and the Notes shall
bind its successors. All agreements of the Trustee in this Indenture shall bind
its successors.


Section 11.11.  Severability.

         In case any provision in this Indenture or in the Notes shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

Section 11.12.  Counterpart Originals.

         The parties may sign any number of copies of this Indenture. Each
signed copy shall be an original, but all of them together represent the same
agreement.

Section 11.13.  Table of Contents, Headings, etc.

         The Table of Contents, Cross-Reference Table and Headings of the
Articles and Sections of this Indenture have been inserted for convenience of
reference only, are not to be considered a part of this Indenture and shall in
no way modify or restrict any of the terms or provisions hereof.


                        [Signatures on following page]

                                      81
<PAGE>

                                   SIGNATURES


Dated as of May 16, 2001


                                               Crown Castle International Corp.

                                               By: /s/ E. Blake Hawk
                                                  ----------------------------
                                               Name: E. Blake Hawk
                                               Title: Executive Vice President

Attest:


______________________
Name:
Title:





                                               The Bank of New York

                                               By: /s/ Van K. Brown
                                                  ----------------------------
                                               Name: Van K. Brown
                                               Title: Vice President
Attest:


______________________
Authorized Signatory
Date:
<PAGE>

                                                                       EXHIBIT A


                                [Face of Note]
--------------------------------------------------------------------------------

                                                   144A Note CUSIP: 228227AK0
                                                    144A Note ISIN: US228227AK00
                                                  Reg S Note CUSIP: U2159JAD2
                                                   Reg S Note ISIN: USU2159JAD29
                                                    IAI Note CUSIP: 228227AR5
                                                     IAI Note ISIN: US228227AR52

                         9 3/8% Senior Notes due 2011

No. ___                                            $____________


                       CROWN CASTLE INTERNATIONAL CORP.

promises to pay to CEDE & CO. or registered assigns,
the principal sum of ____________________________________________________DOLLARS
on August 1, 2011.

Interest Payment Dates:  February 1 and August 1

Record Dates:  January 15 and July 15

       Dated:  May 16, 2001


                                              CROWN CASTLE INTERNATIONAL CORP.

                                              By: /S/ E. Blake Hawk
                                                 -------------------------------
                                                 Name: E. Blake Hawk
                                                 Title: Executive Vice President


                                              By: /s/ [SIGNATURE ILLEGIBLE]
                                                 -------------------------------
                                                 Name:
                                                 Title:

This is one of the Notes referred to
in the within-mentioned Indenture:

The Bank of New York,
  as Trustee

By: __________________________________
      Authorized Signatory

--------------------------------------------------------------------------------
<PAGE>

                                [Back of Note]
                           9 % Senior Notes due 2011

[Insert the Global Note Legend, if applicable, pursuant to the provisions of the
Indenture]

[Insert the Private Placement Legend, if applicable, pursuant to the provisions
of the Indenture]

         Capitalized terms used herein shall have the meanings assigned to them
in the Indenture referred to below unless otherwise indicated.

         1. Interest. Crown Castle International Corp., a Delaware corporation
(the "Company"), promises to pay interest on the principal amount of this Note
at 9 3/8% per annum from May 16, 2001 until maturity. The Company will pay
interest semi-annually in arrears on February 1 and August 1 of each year, or if
any such day is not a Business Day, on the next succeeding Business Day (each an
"Interest Payment Date"). Interest on the Notes will accrue from the most recent
date to which interest has been paid or, if no interest has been paid, from the
date of issuance; provided that if there is no existing Default in the payment
of interest, and if this Note is authenticated between a record date referred to
on the face hereof and the next succeeding Interest Payment Date, interest shall
accrue from such next succeeding Interest Payment Date; provided, further, that
the first Interest Payment Date shall be August 1, 2001. The Company shall pay
interest (including post-petition interest in any proceeding under any
Bankruptcy Law) on overdue principal and premium and Special Interest, if any,
from time to time on demand at a rate that is 1% per annum in excess of the rate
then in effect; it shall pay interest (including post-petition interest in any
proceeding under any Bankruptcy Law) on overdue installments of interest
(without regard to any applicable grace periods) from time to time on demand at
the same rate to the extent lawful. Interest will be computed on the basis of a
360-day year of twelve 30-day months.

         2. Method of Payment. The Company will pay interest on the Notes
(except defaulted interest) to the Persons who are registered Holders of Notes
at the close of business on the January 15 or July 15 next preceding the
Interest Payment Date, even if such Notes are canceled after such record date
and on or before such Interest Payment Date, except as provided in Section 2.12
of the Indenture with respect to defaulted interest. The Notes will be payable
as to principal, premium, if any, and interest at the office or agency of the
Company maintained for such purpose within or without the City and State of New
York, or, at the option of the Company, payment of interest may be made by check
mailed to the Holders at their addresses set forth in the register of Holders,
and provided that payment by wire transfer of immediately available funds will
be required with respect to principal of and interest, premium on, all Global
Notes and all other Notes the Holders of which shall have provided wire transfer
instructions to the Company or the Paying Agent. Such payment shall be in such
coin or currency of the United States of America as at the time of payment is
legal tender for payment of public and private debts.

         3. Paying Agent and Registrar. Initially, United States Trust Company
of New York, the Trustee under the Indenture, will act as Paying Agent and
Registrar. The Company may change any Paying Agent or Registrar without notice
to any Holder. The Company or any of its Subsidiaries may act in any such
capacity.

         4. Indenture. The Company issued the Notes under an Indenture dated as
May 16, 2001 ("Indenture") between the Company and the Trustee. The terms of the
Notes include those stated in the Indenture and those made part of the Indenture
by reference to the Trust Indenture Act of 1939, as amended (15 U.S. Code (S)(S)
77aaa-77bbbb) (the "Trust Indenture Act"). The Notes are subject to all such
terms, and Holders are referred to the Indenture and such Act for a statement of
such terms. To the extent any provision of this Note conflicts with the express
provisions of the Indenture, the provisions of the Indenture shall govern and be
controlling. The Notes are obligations of the Company limited to $550,000,000
million in aggregate principal amount.

                                      A-2
<PAGE>

         5.  Optional Redemption.

         (a) Except as provided in clause (b) of this Paragraph 5, the Notes
will not be redeemable at the Company's option prior to August 1, 2006. On or
after August 1, 2006, the Company may redeem all or a part of the Notes upon not
less than 30 nor more than 60 days' notice, at the redemption prices (expressed
as percentages of principal amount) set forth below plus accrued and unpaid
interest, if any, on the Notes redeemed to the applicable redemption date
(subject to the right of Holders of record on the relevant record date to
receive interest due on the relevant interest payment date), if redeemed during
the twelve-month period beginning on August 1 of the years indicated below:

         Year                                             Percentage
         ----                                             ----------
         2006......................................        104.688%
         2007......................................        103.125%
         2008......................................        101.563%
         2009 and thereafter.......................        100.000%

         (b) Notwithstanding the provisions of clause (a) of this Paragraph 5,
at any time during the period after the date of the original issuance of the
Notes until August 1, 2004, the Company may on any one or more occasions redeem
up to 35% of the aggregate principal amount of the Notes originally issued at a
redemption price equal to 109.375% of the aggregate principal amount of the
Notes to be redeemed on the redemption date with the net cash proceeds of one or
more Public Equity Offerings and/or Strategic Equity Investments provided that:

         (1) at least 65% of the aggregate principal amount of the Notes
originally issued remains outstanding immediately after the occurrence of such
redemption (excluding Notes held by the Company or any of its Subsidiaries); and

         (2) the redemption occurs within 60 days of the date of the closing of
such Public Equity Offering or Strategic Equity Investment.

         6.  Mandatory Redemption.

         Except as set forth in paragraph 7 below, the Company shall not be
required to make mandatory redemption payments with respect to the Notes.

         7.  Repurchase at Option of Holder.

         (a) If there is a Change of Control, the Company shall be required to
make an offer (a "Change of Control Offer") to repurchase all or any part (equal
to $1,000 or an integral multiple thereof) of each Holder's Notes at a purchase
price equal to 101% of the aggregate principal amount thereof plus accrued and
unpaid interest thereon, if any, to the date of purchase (the "Change of Control
Payment"). Within 30 days following any Change of Control, the Company shall
mail a notice to each Holder setting forth the procedures governing the Change
of Control Offer as required by the Indenture.

         (b) If the Company or a Restricted Subsidiary consummates any Asset
Sales when the aggregate amount of Excess Proceeds exceeds $10 million, the
Company shall commence an offer to all Holders of Notes (as "Asset Sale Offer")
pursuant to Section 3.09 of the Indenture to purchase the maximum principal
amount of Notes that may be purchased out of the Excess Proceeds at an offer
price in cash in an amount equal to 100% of the principal amount thereof, plus
accrued and unpaid interest thereon, if any, to the date fixed for the closing
of such offer, in accordance with the procedures set forth in the Indenture. To
the extent that the aggregate amount of Notes tendered pursuant to an Asset Sale

                                      A-3
<PAGE>

Offer is less than the Excess Proceeds, the Company (or such Restricted
Subsidiary) may use such deficiency for any purpose not otherwise prohibited by
the Indenture. If the aggregate principal amount of Notes surrendered by Holders
thereof exceeds the amount of Excess Proceeds, the Trustee shall select the
Notes to be purchased on a pro rata basis. Holders of Notes that are the subject
of an offer to purchase will receive an Asset Sale Offer from the Company prior
to any related purchase date and may elect to have such Notes purchased by
completing the form entitled "Option of Holder to Elect Purchase" on the reverse
of the Notes.

         8.  Notice of Redemption. Notice of redemption will be mailed at least
30 days but not more than 60 days before the redemption date to each Holder
whose Notes are to be redeemed at its registered address. Notes in denominations
larger than $1,000 may be redeemed in part but only in whole multiples of
$1,000, unless all of the Notes held by a Holder are to be redeemed. On and
after the redemption date interest ceases to accrue on Notes or portions thereof
called for redemption.

         9.  Denominations, Transfer, Exchange. The Notes are in registered form
without coupons in denominations of $1,000 and integral multiples of $1,000. The
transfer of Notes may be registered and Notes may be exchanged as provided in
the Indenture. The Registrar and the Trustee may require a Holder, among other
things, to furnish appropriate endorsements and transfer documents and the
Company may require a Holder to pay any taxes and fees required by law or
permitted by the Indenture. The Company need not exchange or register the
transfer of any Note or portion of a Note selected for redemption, except for
the unredeemed portion of any Note being redeemed in part. Also, the Company
need not exchange or register the transfer of any Notes for a period of 15 days
before a selection of Notes to be redeemed or during the period between a record
date and the corresponding Interest Payment Date.

         10. Persons Deemed Owners. The registered Holder of a Note may be
treated as its owner for all purposes.

         11. Amendment, Supplement and Waiver. Subject to certain exceptions,
the Indenture or the Notes may be amended or supplemented with the consent of
the Holders of at least a majority in principal amount of the then outstanding
Notes, and any existing default or compliance with any provision of the
Indenture or the Notes may be waived with the consent of the Holders of a
majority in principal amount of the then outstanding Notes. Without the consent
of any Holder of Notes, the Indenture or the Notes may be amended or
supplemented to cure any ambiguity, defect or inconsistency, to provide for
uncertificated Notes in addition to or in place of certificated Notes, to
provide for the assumption of the Company's obligations to Holders of the Notes
in case of a merger or consolidation, to make any change that would provide any
additional rights or benefits to the Holders of the Notes or that does not
adversely affect the legal rights under the Indenture of any such Holder, or to
comply with the requirements of the Securities and Exchange Commission in order
to effect or maintain the qualification of the Indenture under the Trust
Indenture Act.

         12. Defaults and Remedies. Events of Default include: (i) default for
30 days in the payment when due of interest on the Notes; (ii) default in
payment when due of principal of or premium, if any, on the Notes, (iii) failure
by the Company or any of its Subsidiaries to comply with Section 3.09, 4.10,
4.15 or 5.01 of the Indenture; (iv) failure by the Company or any of its
Subsidiaries for 30 days after notice to the Company by the Trustee or the
Holders of at least 25% in principal amount of the Notes then outstanding to
comply with certain other agreements in the Indenture or the Notes; (v) default
under certain other agreements relating to Indebtedness of the Company which
default (a) is caused by a failure to pay principal of or premium, if any, or
interest on such Indebtedness prior to the expiration of the grace period
provided in such Indebtedness on the date of such default or (b) results in the
acceleration of such Indebtedness prior to its express maturity; (vi) certain
final judgments for the payment of money that remain undischarged for a period
of 60 days; and (vii) certain events of bankruptcy or insolvency with

                                      A-4
<PAGE>

respect to the Company or any of its Restricted Subsidiaries. If any Event of
Default occurs and is continuing, the Trustee or the Holders of at least 25% in
principal amount of the then outstanding Notes may declare all the Notes to be
due and payable. Notwithstanding the foregoing, in the case of an Event of
Default arising from certain events of bankruptcy or insolvency, all outstanding
Notes will become due and payable without further action or notice. Holders may
not enforce the Indenture or the Notes except as provided in the Indenture.
Subject to certain limitations, Holders of a majority in principal amount of the
then outstanding Notes may direct the Trustee in its exercise of any trust or
power. The Trustee may withhold from Holders of the Notes notice of any
continuing Default or Event of Default (except a Default or Event of Default
relating to the payment of principal or interest) if it determines that
withholding notice is in their interest. The Holders of a majority in aggregate
principal amount of the Notes then outstanding by notice to the Trustee may on
behalf of the Holders of all of the Notes waive any existing Default or Event of
Default and its consequences under the Indenture except a continuing Default or
Event of Default in the payment of interest on, or the principal of, the Notes.
The Company is required to deliver to the Trustee annually a statement regarding
compliance with the Indenture, and the Company is required upon becoming aware
of any Default or Event of Default, to deliver to the Trustee a statement
specifying such Default or Event of Default.

         13. Trustee Dealings with Company. The Trustee, in its individual or
any other capacity, may make loans to, accept deposits from, and perform
services for the Company or its Affiliates, and may otherwise deal with the
Company or its Affiliates, as if it were not the Trustee.

         14. No Recourse Against Others. A director, officer, employee,
incorporator or stockholder, of the Company, as such, shall not have any
liability for any obligations of the Company under the Notes or the Indenture or
for any claim based on, in respect of, or by reason of, such obligations or
their creation. Each Holder by accepting a Note waives and releases all such
liability. The waiver and release are part of the consideration for the issuance
of the Notes.

         15. Authentication. This Note shall not be valid until authenticated by
the manual signature of the Trustee or an authenticating agent.

         16. Abbreviations. Customary abbreviations may be used in the name of a
Holder or an assignee, such as: TEN COM (= tenants in common), TEN ENT (=
tenants by the entireties), JT TEN (= joint tenants with right of survivorship
and not as tenants in common), CUST (= Custodian), and U/G/M/A (= Uniform Gifts
to Minors Act).

         17. CUSIP Numbers. Pursuant to a recommendation promulgated by the
Committee on Uniform Security Identification Procedures, the Company has caused
CUSIP numbers to be printed on the Notes and the Trustee may use CUSIP numbers
in notices of redemption as a convenience to Holders. No representation is made
as to the accuracy of such numbers either as printed on the Notes or as
contained in any notice of redemption and reliance may be placed only on the
other identification numbers placed thereon.

The Company will furnish to any Holder upon written request and without charge a
copy of the Indenture. Requests may be made to: Crown Castle International
Corp., 510 Bering Drive, Suite 500, Houston, Texas 77057, Attention: Chief
Financial Officer.

                                      A-5
<PAGE>

                                 Assignment Form

     To assign this Note, fill in the form below:

(I) or (we) assign and transfer this Note to:
                                             ___________________________________
                                                (Insert assignee's legal name)

________________________________________________________________________________
                 (Insert assignee's soc. sec. or tax I.D. no.)

________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
             (Print or type assignee's name, address and zip code)

and irrevocably appoint ________________________________________________________
to transfer this Note on the books of the Company. The agent may substitute
another to act for him.

Date:__________________

                                        Your Signature:_________________________
                                              (Sign exactly as your name appears
                                                       on the face of this Note)


Signature Guarantee*:___________________

* Participant in a recognized Signature Guarantee Medallion Program (or other
signature guarantor acceptable to the Trustee).

                                      A-6
<PAGE>

                      Option of Holder to Elect Purchase

     If you want to elect to have this Note purchased by the Company pursuant to
Section 4.10 or 4.15 of the Indenture, check the appropriate box below:

               [_] Section 4.10         [_] Section 4.15

     If you want to elect to have only part of the Note purchased by the Company
pursuant to Section 4.10 or Section 4.15 of the Indenture, state the amount you
elect to have purchased:

                               $________________

Date:________________

                                          Your Signature:_______________________
                                              (Sign exactly as your name appears
                                                       on the face of this Note)


                                          Tax Identification No.:_______________

Signature Guarantee*:____________________

* Participant in a recognized Signature Guarantee Medallion Program (or other
signature guarantor acceptable to the Trustee).

                                      A-7
<PAGE>

            SCHEDULE OF EXCHANGES OF INTERESTS IN THE GLOBAL NOTE*

     The following exchanges of a part of this Global Note for an interest in
another Global Note or for a Definitive Note, or exchanges of a part of another
Global Note or Definitive Note for an interest in this Global Note, have been
made:

<TABLE>
                                                                                                           Signature of
                                                                             Principal Amount of      authorized officer of
                        Amount of decrease in     Amount of increase in        this Global Note             Trustee or
                         Principal Amount of       Principal Amount of     following such decrease             Note
   Date of Exchange       this Global Note           this Global Note           (or increase)               Custodian
   ----------------       ----------------           ----------------           -------------               ---------
   <S>                  <C>                       <C>                      <C>                        <C>
</TABLE>

* This schedule should be included only if the Note is issued in global form.

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

                                      A-8
<PAGE>

                                                                       EXHIBIT B

                        FORM OF CERTIFICATE OF TRANSFER

Crown Castle International Corp.
510 Bering Drive, Suite 500
Houston, Texas 77057

[Registrar address block]

         Re:  $ 450,000,000 9 % Senior Notes Due 2011

                  Reference is hereby made to the Indenture, dated as of May 16,
2001 (the "Indenture"), between Crown Castle International Corp., as issuer (the
"Company"), and The Bank of New York, as trustee. Capitalized terms used but not
defined herein shall have the meanings given to them in the Indenture.

                  ___________________, (the "Transferor") owns and proposes to
transfer the Note[s] or interest in such Note[s] specified in Annex A hereto, in
the principal amount of $___________ in such Note[s] or interests (the
"Transfer"), to ___________________________ (the "Transferee"), as further
specified in Annex A hereto. In connection with the Transfer, the Transferor
hereby certifies that:

                             [CHECK ALL THAT APPLY]

                  1. [_] Check if Transferee will take delivery of a beneficial
                         ------------------------------------------------------
interest in the 144A Global Note or a Definitive Note Pursuant to Rule 144A. The
---------------------------------------------------------------------------
Transfer is being effected pursuant to and in accordance with Rule 144A under
the United States Securities Act of 1933, as amended (the "Securities Act"),
and, accordingly, the Transferor hereby further certifies that the beneficial
interest or Definitive Note is being transferred to a Person that the Transferor
reasonably believed and believes is purchasing the beneficial interest or
Definitive Note for its own account, or for one or more accounts with respect to
which such Person exercises sole investment discretion, and such Person and each
such account is a "qualified institutional buyer" within the meaning of Rule
144A in a transaction meeting the requirements of Rule 144A and such Transfer is
in compliance with any applicable blue sky securities laws of any state of the
United States. Upon consummation of the proposed Transfer in accordance with the
terms of the Indenture, the transferred beneficial interest or Definitive Note
will be subject to the restrictions on transfer enumerated in the Private
Placement Legend printed on the 144A Global Note and/or the Definitive Note and
in the Indenture and the Securities Act.

                  2. [_] Check if Transferee will take delivery of a beneficial
                         ------------------------------------------------------
interest in the Regulation S Global Note or a Definitive Note pursuant to
-------------------------------------------------------------------------
Regulation S. The Transfer is being effected pursuant to and in accordance with
------------
Rule 903 or Rule 904 under the Securities Act and, accordingly, the Transferor
hereby further certifies that (i) the Transfer is not being made to a person in
the United States and (x) at the time the buy order was originated, the
Transferee was outside the United States or such Transferor and any Person
acting on its behalf reasonably believed and believes that the Transferee was
outside the United States or (y) the transaction was executed in, on or through
the facilities of a designated offshore securities market and neither such
Transferor nor any Person acting on its behalf knows that the transaction was
prearranged with a buyer in the United States, (ii) no directed selling efforts
have been made in contravention of the requirements of Rule 903(b) or Rule
904(b) of Regulation S under the Securities Act, (iii) the transaction is not
part of a plan or scheme to evade the registration requirements of the
Securities Act, and (iv) if the proposed transfer is being made prior to the

                                      B-1
<PAGE>

expiration of the Restricted Period, the transfer is not being made to a U.S.
Person or for the account or benefit of a U.S. Person (other than an Initial
Purchaser). Upon consummation of the proposed transfer in accordance with the
terms of the Indenture, the transferred beneficial interest or Definitive Note
will be subject to the restrictions on Transfer enumerated in the Private
Placement Legend printed on the Regulation S Global Note, and/or the Definitive
Note and in the Indenture and the Securities Act.

                  3. [_] Check and complete if Transferee will take delivery of
                         ------------------------------------------------------
a beneficial interest in the IAI Global Note or a Definitive Note pursuant to
-------------------------------------------------------------------------------
any provision of the Securities Act other than Rule 144A or Regulation S. The
------------------------------------------------------------------------
Transfer is being effected in compliance with the transfer restrictions
applicable to beneficial interests in Restricted Global Notes and Restricted
Definitive Notes and pursuant to and in accordance with the Securities Act and
any applicable blue sky securities laws of any state of the United States, and
accordingly the Transferor hereby further certifies that (check one):

                  (a) [_] such Transfer is being effected pursuant to and in
           accordance with Rule 144 under the Securities Act;

                                       OR

                  (b) [_] such Transfer is being effected to the Company or a
           subsidiary thereof;

                                       OR

                  (c) [_] such Transfer is being effected pursuant to an
           effective registration statement under the Securities Act and in
           compliance with the prospectus delivery requirements of the
           Securities Act;

                                       OR

                  (d) [_] such Transfer is being effected to an Institutional
           Accredited Investor and pursuant to an exemption from the
           registration requirements of the Securities Act other than Rule 144A,
           Rule 144 or Rule 904, and the Transferor hereby further certifies
           that it has not engaged in any general solicitation within the
           meaning of Regulation D under the Securities Act and the Transfer
           complies with the transfer restrictions applicable to beneficial
           interests in a Restricted Global Note or Restricted Definitive Notes
           and the requirements of the exemption claimed, which certification is
           supported by (1) a certificate executed by the Transferee in the form
           of Exhibit D to the Indenture and (2) an Opinion of Counsel provided
           by the Transferor or the Transferee (a copy of which the Transferor
           has attached to this certification), to the effect that such Transfer
           is in compliance with the Securities Act. Upon consummation of the
           proposed transfer in accordance with the terms of the Indenture, the
           transferred beneficial interest or Definitive Note will be subject to
           the restrictions on transfer enumerated in the Private Placement
           Legend printed on the IAI Global Note and/or the Definitive Notes and
           in the Indenture and the Securities Act.

                  4.  [_] Check if Transferee will take delivery of a beneficial
                          ------------------------------------------------------
interest in an Unrestricted Global Note or of an Unrestricted Definitive Note.
-----------------------------------------------------------------------------

                  (a) [_] Check if Transfer is pursuant to Rule 144. (i) The
Transfer is being effected pursuant to and in accordance with Rule 144 under the
Securities Act and in compliance with the transfer restrictions contained in the
Indenture and any applicable blue sky securities laws of any state of the United
States and (ii) the restrictions on transfer contained in the Indenture and the
Private Placement

                                      B-2
<PAGE>

Legend are not required in order to maintain compliance with the Securities Act.
Upon consummation of the proposed Transfer in accordance with the terms of the
Indenture, the transferred beneficial interest or Definitive Note will no longer
be subject to the restrictions on transfer enumerated in the Private Placement
Legend printed on the Restricted Global Notes, on Restricted Definitive Notes
and in the Indenture.

                 (b) [_] Check if Transfer is Pursuant to Regulation S. (i) The
Transfer is being effected pursuant to and in accordance with Rule 903 or Rule
904 under the Securities Act and in compliance with the transfer restrictions
contained in the Indenture and any applicable blue sky securities laws of any
state of the United States and (ii) the restrictions on transfer contained in
the Indenture and the Private Placement Legend are not required in order to
maintain compliance with the Securities Act. Upon consummation of the proposed
Transfer in accordance with the terms of the Indenture, the transferred
beneficial interest or Definitive Note will no longer be subject to the
restrictions on transfer enumerated in the Private Placement Legend printed on
the Restricted Global Notes, on Restricted Definitive Notes and in the
Indenture.

                 (c) [_] Check if Transfer is Pursuant to Other Exemption. (i)
The Transfer is being effected pursuant to and in compliance with an exemption
from the registration requirements of the Securities Act other than Rule 144,
Rule 903 or Rule 904 and in compliance with the transfer restrictions contained
in the Indenture and any applicable blue sky securities laws of any State of the
United States and (ii) the restrictions on transfer contained in the Indenture
and the Private Placement Legend are not required in order to maintain
compliance with the Securities Act. Upon consummation of the proposed Transfer
in accordance with the terms of the Indenture, the transferred beneficial
interest or Definitive Note will not be subject to the restrictions on transfer
enumerated in the Private Placement Legend printed on the Restricted Global
Notes or Restricted Definitive Notes and in the Indenture.

                 This certificate and the statements contained herein are made
for your benefit and the benefit of the Company.


                                            ___________________________________
                                               [Insert Name of Transferor]



                                            By:________________________________
                                              Name:
                                              Title:

                 Dated:  _______________________


                                      B-3
<PAGE>

                       ANNEX A TO CERTIFICATE OF TRANSFER

             1.  The Transferor owns and proposes to transfer the following:

                            [CHECK ONE OF (A) OR (B)]

     (a) [_] a beneficial interest in the:

                            (i)   [_]   144A Global Note (CUSIP _________), or

                            (ii)  [_]   Regulation S Global Note (CUSIP
_________), or

                            (iii) [_] IAI Global Note (CUSIP _________); or

                        (b) [_] a Restricted Definitive Note.

             2.  After the Transfer the Transferee will hold:

                                   [CHECK ONE]

                        (a) [_]   a beneficial interest in the:

                            (i)   [_]  144A Global Note (CUSIP _________), or

                            (ii)  [_]  Regulation S Global Note (CUSIP
________), or

                            (iii) [_]  IAI Global Note (CUSIP _________); or

                            (iv)  [_]  Unrestricted Global Note (CUSIP
_________); or

                        (b) [_]   a Restricted Definitive Note; or

                        (c) [_]   an Unrestricted Definitive Note,

in accordance with the terms of the Indenture.

                                      B-4
<PAGE>

                                                                       EXHIBIT C

                         FORM OF CERTIFICATE OF EXCHANGE

Crown Castle International Corp.
510 Bering Drive, Suite 500
Houston, Texas 77057


[Registrar address block]

         Re: $450,000,000 9 % Senior Notes due 2011

                              (CUSIP ____________)

                  Reference is hereby made to the Indenture, dated as of May 16,
2001 (the "Indenture"), between Crown Castle International Corp., as issuer (the
"Company"), and The Bank of New York, as trustee. Capitalized terms used but not
defined herein shall have the meanings given to them in the Indenture.

                  __________________________, (the "Owner") owns and proposes to
exchange the Note[s] or interest in such Note[s] specified herein, in the
principal amount of $____________ in such Note[s] or interests (the "Exchange").
In connection with the Exchange, the Owner hereby certifies that:

                  1.  Exchange of Restricted Definitive Notes or Beneficial
                      -----------------------------------------------------
Interests in a Restricted Global Note for Unrestricted Definitive Notes or
--------------------------------------------------------------------------
Beneficial Interests in an Unrestricted Global Note
---------------------------------------------------

                  (a) [_]  Check if Exchange is from beneficial interest in a
Restricted Global Note to beneficial interest in an Unrestricted Global Note. In
connection with the Exchange of the Owner's beneficial interest in a Restricted
Global Note for a beneficial interest in an Unrestricted Global Note in an equal
principal amount, the Owner hereby certifies (i) the beneficial interest is
being acquired for the Owner's own account without transfer, (ii) such Exchange
has been effected in compliance with the transfer restrictions applicable to the
Global Notes and pursuant to and in accordance with the United States Securities
Act of 1933, as amended (the "Securities Act"), (iii) the restrictions on
transfer contained in the Indenture and the Private Placement Legend are not
required in order to maintain compliance with the Securities Act and (iv) the
beneficial interest in an Unrestricted Global Note is being acquired in
compliance with any applicable blue sky securities laws of any state of the
United States.

                  (b) [_]  Check if Exchange is from beneficial interest in a
Restricted Global Note to Unrestricted Definitive Note. In connection with the
Exchange of the Owner's beneficial interest in a Restricted Global Note for an
Unrestricted Definitive Note, the Owner hereby certifies (i) the Definitive Note
is being acquired for the Owner's own account without transfer, (ii) such
Exchange has been effected in compliance with the transfer restrictions
applicable to the Restricted Global Notes and pursuant to and in accordance with
the Securities Act, (iii) the restrictions on transfer contained in the
Indenture and the Private Placement Legend are not required in order to maintain
compliance with the Securities Act and (iv) the Definitive Note is being
acquired in compliance with any applicable blue sky securities laws of any state
of the United States.

                                      C-1
<PAGE>

                  (c) [_] Check if Exchange is from Restricted Definitive Note
to beneficial interest in an Unrestricted Global Note. In connection with the
Owner's Exchange of a Restricted Definitive Note for a beneficial interest in an
Unrestricted Global Note, the Owner hereby certifies (i) the beneficial interest
is being acquired for the Owner's own account without transfer, (ii) such
Exchange has been effected in compliance with the transfer restrictions
applicable to Restricted Definitive Notes and pursuant to and in accordance with
the Securities Act, (iii) the restrictions on transfer contained in the
Indenture and the Private Placement Legend are not required in order to maintain
compliance with the Securities Act and (iv) the beneficial interest is being
acquired in compliance with any applicable blue sky securities laws of any state
of the United States.

                  (d) [_] Check if Exchange is from Restricted Definitive Note
to Unrestricted Definitive Note. In connection with the Owner's Exchange of a
Restricted Definitive Note for an Unrestricted Definitive Note, the Owner hereby
certifies (i) the Unrestricted Definitive Note is being acquired for the Owner's
own account without transfer, (ii) such Exchange has been effected in compliance
with the transfer restrictions applicable to Restricted Definitive Notes and
pursuant to and in accordance with the Securities Act, (iii) the restrictions on
transfer contained in the Indenture and the Private Placement Legend are not
required in order to maintain compliance with the Securities Act and (iv) the
Unrestricted Definitive Note is being acquired in compliance with any applicable
blue sky securities laws of any state of the United States.

                  2.  [_] Exchange of Restricted Definitive Notes or Beneficial
                          -----------------------------------------------------
Interests in Restricted Global Notes for Restricted Definitive Notes or
-----------------------------------------------------------------------
Beneficial Interests in Restricted Global Notes
-----------------------------------------------

                  (a) [_] Check if Exchange is from beneficial interest in a
Restricted Global Note to Restricted Definitive Note. In connection with the
Exchange of the Owner's beneficial interest in a Restricted Global Note for a
Restricted Definitive Note with an equal principal amount, the Owner hereby
certifies that the Restricted Definitive Note is being acquired for the Owner's
own account without transfer. Upon consummation of the proposed Exchange in
accordance with the terms of the Indenture, the Restricted Definitive Note
issued will continue to be subject to the restrictions on transfer enumerated in
the Private Placement Legend printed on the Restricted Definitive Note and in
the Indenture and the Securities Act.

                  (b) [_] Check if Exchange is from Restricted Definitive Note
to beneficial interest in a Restricted Global Note. In connection with the
Exchange of the Owner's Restricted Definitive Note for a beneficial interest in
the [CHECK ONE] 144A Global Note, Regulation S Global Note, IAI Global Note with
an equal principal amount, the Owner hereby certifies (i) the beneficial
interest is being acquired for the Owner's own account without transfer and (ii)
such Exchange has been effected in compliance with the transfer restrictions
applicable to the Restricted Global Notes and pursuant to and in accordance with
the Securities Act, and in compliance with any applicable blue sky securities
laws of any state of the United States. Upon consummation of the proposed
Exchange in accordance with the terms of the Indenture, the beneficial interest
issued will be subject to the restrictions on transfer enumerated in the Private
Placement Legend printed on the relevant Restricted Global Note and in the
Indenture and the Securities Act.

                  This certificate and the statements contained herein are made
for your benefit and the benefit of the Company.

                                     C-2


<PAGE>

                                               _________________________________
                                                  [Insert Name of Transferor]


                                              By:
                                                 -----------------------------
                                              Name:
                                              Title:

Dated:  ______________________

                                      C-3
<PAGE>

                                                                       EXHIBIT D

                            FORM OF CERTIFICATE FROM
                   ACQUIRING INSTITUTIONAL ACCREDITED INVESTOR

Crown Castle International Corp.
510 Bering Drive, Suite 500
Houston, Texas 77057


[Registrar address block]

         Re:  $450,000,00 9 % Senior Notes due 2011

                  Reference is hereby made to the Indenture, dated as of May 16,
2001 (the "Indenture"), between Crown Castle International Corp., as issuer (the
"Company"), and The Bank of New York, as trustee. Capitalized terms used but not
defined herein shall have the meanings given to them in the Indenture.

                  In connection with our proposed purchase of $____________
aggregate principal amount of:

                  (a) [_]  a beneficial interest in a Global Note, or

                  (b) [_]  a Definitive Note,

                  we confirm that:

                  1. We understand that any subsequent transfer of the Notes or
any interest therein is subject to certain restrictions and conditions set forth
in the Indenture and the undersigned agrees to be bound by, and not to resell,
pledge or otherwise transfer the Notes or any interest therein except in
compliance with, such restrictions and conditions and the United States
Securities Act of 1933, as amended (the "Securities Act").

                  2. We understand that the offer and sale of the Notes have not
been registered under the Securities Act, and that the Notes and any interest
therein may not be offered or sold except as permitted in the following
sentence. We agree, on our own behalf and on behalf of any accounts for which we
are acting as hereinafter stated, that if we should sell the Notes or any
interest therein, we will do so only (A) to the Company or any subsidiary
thereof, (B) in accordance with Rule 144A under the Securities Act to a
"qualified institutional buyer" (as defined therein), (C) to an institutional
"accredited investor" (as defined below) that, prior to such transfer, furnishes
(or has furnished on its behalf by a U.S. broker-dealer) to you and to the
Company a signed letter substantially in the form of this letter and an Opinion
of Counsel in form reasonably acceptable to the Company to the effect that such
transfer is in compliance with the Securities Act, (D) outside the United States
in accordance with Rule 904 of Regulation S under the Securities Act, (E)
pursuant to the provisions of Rule 144(k) under the Securities Act or (F)
pursuant to an effective registration statement under the Securities Act, and we
further agree to provide to any person purchasing the Definitive Note or
beneficial interest in a Global Note from us in a transaction meeting the
requirements of clauses (A) through (E) of this paragraph a notice advising such
purchaser that resales thereof are restricted as stated herein.

                                      D-1
<PAGE>

                  3. We understand that, on any proposed resale of the Notes or
beneficial interest therein, we will be required to furnish to you and the
Company such certifications, legal opinions and other information as you and the
Company may reasonably require to confirm that the proposed sale complies with
the foregoing restrictions. We further understand that the Notes purchased by us
will bear a legend to the foregoing effect.

                  4. We are an institutional "accredited investor" (as defined
in Rule 501(a)(1), (2), (3) or (7) of Regulation D under the Securities Act) and
have such knowledge and experience in financial and business matters as to be
capable of evaluating the merits and risks of our investment in the Notes, and
we and any accounts for which we are acting are each able to bear the economic
risk of our or its investment.

                  5. We are acquiring the Notes or beneficial interest therein
purchased by us for our own account or for one or more accounts (each of which
is an institutional "accredited investor") as to each of which we exercise sole
investment discretion.

                  You and the Company are entitled to rely upon this letter and
are irrevocably authorized to produce this letter or a copy hereof to any
interested party in any administrative or legal proceedings or official inquiry
with respect to the matters covered hereby.

                                          _____________________________________
                                          [Insert Name of Accredited Investor]


                                         By:__________________________________
                                           Name:
                                           Title:

Dated: _______________________

                                      D-2
<PAGE>

                                                                       EXHIBIT E

                         FORM OF SUPPLEMENTAL INDENTURE
                    TO BE DELIVERED BY SUBSEQUENT GUARANTORS


         Supplemental Indenture (this "Supplemental Indenture"), dated as of
________, among __________________ (the "Guaranteeing Subsidiary"), a subsidiary
of CROWN CASTLE INTERNATIONAL CORP. (or its permitted successor), a Delaware
corporation (the "Company"), the Company, the other Guarantors (as defined in
the Indenture referred to herein) and THE BANK OF NEW YORK, as trustee under the
Indenture referred to below (the "Trustee").

                              W I T N E S S E T H

         WHEREAS, the Company has heretofore executed and delivered to the
Trustee an indenture (the "Indenture"), dated as of May 16, 2001 providing for
the issuance of an aggregate principal amount of up to $550.0 million of
9 % Senior Notes due 2011 (the "Notes");

         WHEREAS, the Indenture provides that under certain circumstances the
Guaranteeing Subsidiary shall execute and deliver to the Trustee a supplemental
indenture pursuant to which the Guaranteeing Subsidiary shall unconditionally
guarantee all of the Company's Obligations under the Notes and the Indenture on
the terms and conditions set forth herein (the "Note Guarantee"); and

         WHEREAS, pursuant to Section 9.1 of the Indenture, the Trustee is
authorized to execute and deliver this Supplemental Indenture.

         NOW THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the
Guaranteeing Subsidiary and the Trustee mutually covenant and agree for the
equal and ratable benefit of the Holders of the Notes as follows:

         1. Capitalized Terms.  Capitalized terms used herein without definition
shall have the meanings assigned to them in the Indenture.

         2. Agreement to Guarantee.  The Guaranteeing Subsidiary hereby agrees
as follows:

            (a)  Along with all Guarantors named in the Indenture, to jointly
                 and severally Guarantee to each Holder of a Note authenticated
                 and delivered by the Trustee and to the Trustee and its
                 successors and assigns, irrespective of the validity and
                 enforceability of the Indenture, the Notes or the obligations
                 of the Company hereunder or thereunder, that:

                 (i)  the principal of and interest on the Notes will be
                      promptly paid in full when due, whether at maturity, by
                      acceleration, redemption or otherwise, and interest on the
                      overdue principal of and interest on the Notes, if any, if
                      lawful, and all other obligations of the Company to the
                      Holders or the Trustee hereunder or thereunder will be
                      promptly paid in full or performed, all in accordance with
                      the terms hereof and thereof; and

                 (ii) in case of any extension of time of payment or renewal of
                      any Notes or any of such other obligations, that same will
                      be promptly paid in full when due or performed in
                      accordance with the terms of the extension or

                                      E-1
<PAGE>

                                    renewal, whether at stated maturity, by
                                    acceleration or otherwise. Failing payment
                                    when due of any amount so guaranteed or any
                                    performance so guaranteed for whatever
                                    reason, the Guarantors shall be jointly and
                                    severally obligated to pay the same
                                    immediately.

                  (b)      The obligations hereunder shall be unconditional,
                           irrespective of the validity, regularity or
                           enforceability of the Notes or the Indenture, the
                           absence of any action to enforce the same, any waiver
                           or consent by any Holder of the Notes with respect to
                           any provisions hereof or thereof, the recovery of any
                           judgment against the Company, any action to enforce
                           the same or any other circumstance which might
                           otherwise constitute a legal or equitable discharge
                           or defense of a guarantor.

                  (c)      The following is hereby waived: diligence,
                           presentment, demand of payment, filing of claims with
                           a court in the event of insolvency or bankruptcy of
                           the Company, any right to require a proceeding first
                           against the Company, protest, notice and all demands
                           whatsoever.

                  (d)      This Note Guarantee shall not be discharged except by
                           complete performance of the obligations contained in
                           the Notes and the Indenture.

                  (e)      If any Holder or the Trustee is required by any court
                           or otherwise to return to the Company, the
                           Guarantors, or any Custodian, Trustee, liquidator or
                           other similar official acting in relation to either
                           the Company or the Guarantors, any amount paid by
                           either to the Trustee or such Holder, this Note
                           Guarantee, to the extent theretofore discharged,
                           shall be reinstated in full force and effect.

                  (f)      The Guaranteeing Subsidiary shall not be entitled to
                           any right of subrogation in relation to the Holders
                           in respect of any obligations guaranteed hereby until
                           payment in full of all obligations guaranteed hereby.

                  (g)      As between the Guarantors, on the one hand, and the
                           Holders and the Trustee, on the other hand, (x) the
                           maturity of the obligations guaranteed hereby may be
                           accelerated as provided in Article 6 of the Indenture
                           for the purposes of this Note Guarantee,
                           notwithstanding any stay, injunction or other
                           prohibition preventing such acceleration in respect
                           of the obligations guaranteed hereby, and (y) in the
                           event of any declaration of acceleration of such
                           obligations as provided in Article 6 of the
                           Indenture, such obligations (whether or not due and
                           payable) shall forthwith become due and payable by
                           the Guarantors for the purpose of this Note
                           Guarantee.

                  (h)      The Guarantors shall have the right to seek
                           contribution from any non-paying Guarantor so long as
                           the exercise of such right does not impair the rights
                           of the Holders under the Guarantee.

                  (i)      Pursuant to Section 10.02 of the Indenture, after
                           giving effect to any maximum amount and any other
                           contingent and fixed liabilities that are relevant
                           under any applicable Bankruptcy or fraudulent
                           conveyance laws, and after giving effect to any
                           collections from, rights to receive contribution from
                           or payments made by or on behalf of any other
                           Guarantor in respect of the obligations of such other

                                      E-2
<PAGE>

                           Guarantor under Article 10 of the Indenture shall
                           result in the obligations of such Guarantor under its
                           Note Guarantee not constituting a fraudulent transfer
                           or conveyance.

         3.  Execution and Delivery. Each Guaranteeing Subsidiary agrees that
the Note Guarantees shall remain in full force and effect notwithstanding any
failure to endorse on each Note a notation of such Note Guarantee.

         4.  Guaranteeing Subsidiary May Consolidate, Etc. on Certain
Terms.

             (a) The Guaranteeing Subsidiary may not consolidate with or merge
                 with or into (whether or not such Guarantor is the surviving
                 Person) another corporation, Person or entity whether or not
                 affiliated with such Guarantor unless:

                 (i)  subject to Section 10.05 of the Indenture, the Person
                      formed by or surviving any such consolidation or merger
                      (if other than a Guarantor or the Company) unconditionally
                      assumes all the obligations of such Guarantor, pursuant to
                      a supplemental indenture in form and substance reasonably
                      satisfactory to the Trustee, under the Notes, the
                      Indenture and the Note Guarantee on the terms set forth
                      herein or therein; and

                 (ii) immediately after giving effect to such transaction, no
                      Default or Event of Default exists.

             (b) In case of any such consolidation, merger, sale or conveyance
                 and upon the assumption by the successor corporation, by
                 supplemental indenture, executed and delivered to the Trustee
                 and satisfactory in form to the Trustee, of the Note Guarantee
                 endorsed upon the Notes and the due and punctual performance of
                 all of the covenants and conditions of the Indenture to be
                 performed by the Guarantor, such successor corporation shall
                 succeed to and be substituted for the Guarantor with the same
                 effect as if it had been named herein as a Guarantor. Such
                 successor corporation thereupon may cause to be signed any or
                 all of the Note Guarantees to be endorsed upon all of the Notes
                 issuable hereunder which theretofore shall not have been signed
                 by the Company and delivered to the Trustee. All the Note
                 Guarantees so issued shall in all respects have the same legal
                 rank and benefit under the Indenture as the Note Guarantees
                 theretofore and thereafter issued in accordance with the terms
                 of the Indenture as though all of such Note Guarantees had been
                 issued at the date of the execution hereof.

             (c) Except as set forth in Articles 4 and 5 of the Indenture, and
                 notwithstanding clauses (a) and (b) above, nothing contained in
                 the Indenture or in any of the Notes shall prevent any
                 consolidation or merger of a Guarantor with or into the Company
                 or another Guarantor, or shall prevent any sale or conveyance
                 of the property of a Guarantor as an entirety or substantially
                 as an entirety to the Company or another Guarantor.

         5.  Releases.

             (a) In the event of a sale or other disposition of all of the
                 assets of any Guarantor, by way of merger, consolidation or
                 otherwise, or a sale or other disposition of all to the capital
                 stock of any Guarantor, then such Guarantor (in the event of a
                 sale or other disposition, by way of merger, consolidation or
                 otherwise, of all of the capital stock of such Guarantor) or
                 the corporation acquiring the property (in the event of a sale
                 or

                                      E-3
<PAGE>

                  other disposition of all or substantially all of the assets of
                  such Guarantor) will be released and relieved of any
                  obligations under its Note Guarantee; provided that the Net
                  Proceeds of such sale or other disposition are applied in
                  accordance with the applicable provisions of the Indenture,
                  including without limitation Section 4.10 of the Indenture.
                  Upon delivery by the Company to the Trustee of an Officers'
                  Certificate and an Opinion of Counsel to the effect that such
                  sale or other disposition was made by the Company in
                  accordance with the provisions of the Indenture, including
                  without limitation Section 4.10 of the Indenture, the Trustee
                  shall execute any documents reasonably required in order to
                  evidence the release of any Guarantor from its obligations
                  under its Note Guarantee.

             (b)  Any Guarantor not released from its obligations under its Note
                  Guarantee shall remain liable for the full amount of principal
                  of and interest on the Notes and for the other obligations of
                  any Guarantor under the Indenture as provided in Article 10 of
                  the Indenture.

         6.  No Recourse Against Others. No past, present or future director,
officer, employee, incorporator, stockholder or agent of the Guaranteeing
Subsidiary, as such, shall have any liability for any obligations of the Company
or any Guaranteeing Subsidiary under the Notes, any Note Guarantees, the
Indenture or this Supplemental Indenture or for any claim based on, in respect
of, or by reason of, such obligations or their creation. Each Holder of the
Notes by accepting a Note waives and releases all such liability. The waiver and
release are part of the consideration for issuance of the Notes. Such waiver may
not be effective to waive liabilities under the federal securities laws and it
is the view of the Commission that such a waiver is against public policy.

         7.  New York Law to Govern. THE INTERNAL LAW OF THE STATE OF NEW YORK
SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE BUT WITHOUT
GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT
THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

         8.  Counterparts.  The parties may sign any number of copies of this
Supplemental Indenture. Each signed copy shall be an original, but all of them
together represent the same agreement.

         9.  Effect of Headings. The Section headings herein are for convenience
only and shall not affect the construction hereof.

         10. The Trustee.  The Trustee shall not be responsible in any
manner whatsoever for or in respect of the validity or sufficiency of this
Supplemental Indenture or for or in respect of the recitals contained herein,
all of which recitals are made solely by the Guaranteeing Subsidiary and the
Company.

         IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed and attested, all as of the date first above
written.

Dated:______________

                                      E-4
<PAGE>

                                                       [Guaranteeing Subsidiary]


                                              By:
                                                 ------------------------------
                                               Name:
                                               Title:


                                              Crown Castle International Corp.


                                              By: /s/ [SIGNATURE ILLEGIBLE]
                                                 ------------------------------
                                               Name:
                                               Title:


                                              [Other Guarantors]


                                              By:
                                                --------------------------------
                                                Name:
                                                Title


                                              The Bank of New York
                                              as Trustee


                                              By:
                                                 ------------------------------
                                                 Name:
                                                 Title:

                                      E-5
<PAGE>

                          FORM OF NOTATION OF GUARANTEE


         For value received, each Guarantor (which term includes any successor
Person under the Indenture) has, jointly and severally, unconditionally
guaranteed, to the extent set forth in the Indenture and subject to the
provisions in the Indenture dated as of May 16, 2001 (the "Indenture") among
CROWN CASTLE INTERNATIONAL CORP. and THE BANK OF NEW YORK, as trustee (the
"Trustee"), (a) the due and punctual payment of the principal of, premium, if
any, and interest on the Notes (as defined in the Indenture), whether at
maturity, by acceleration, redemption or otherwise, the due and punctual payment
of interest on overdue principal and premium, and, to the extent permitted by
law, interest, and the due and punctual performance of all other obligations of
the Company to the Holders or the Trustee all in accordance with the terms of
the Indenture and (b) in case of any extension of time of payment or renewal of
any Notes or any of such other obligations, that the same will be promptly paid
in full when due or performed in accordance with the terms of the extension or
renewal, whether at stated maturity, by acceleration or otherwise. The
obligations of the Guarantors to the Holders of Notes and to the Trustee
pursuant to the Note Guarantee and the Indenture are expressly set forth in
Article 10 of the Indenture and reference is hereby made to the Indenture for
the precise terms of the Note Guarantee. Each Holder of a Note, by accepting the
same, agrees to and shall be bound by such provisions.

                                                          [Name of Guarantor(s)]




                                                           By:
                                                             ------------------
                                                             Name:
                                                             Title:

                                      F-1