<PAGE>   1
                                                                     Exhibit 4.1







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                             XO COMMUNICATIONS, INC.
                                       TO
                               -------------------

                                                 Trustee
                                                 -------



                                    INDENTURE
                         Dated as of ____________, 200__




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




                               ____% SENIOR NOTES
                                    DUE 20__


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<PAGE>   2
                               Table of Contents

                             XO COMMUNICATIONS, INC.
                 Certain Sections of this Indenture relating to
                         Sections 310 through 318 of the
                          Trust Indenture Act of 1939:

<TABLE>
<CAPTION>
Trust Indenture                                                                                 Indenture
Act Section                                                                                      Section
<S>                                                                                             <C>
Section 310(a)(1).............................................................................      609
        (a)(2)................................................................................      609
        (a)(3)................................................................................      Not Applicable
        (a)(4)................................................................................      Not Applicable
        (b)...................................................................................      608, 610
Section 311(a)................................................................................      613
        (b)...................................................................................      613
Section 312(a)................................................................................      701, 702
        (b)...................................................................................      702
        (c)...................................................................................      702
Section 313(a)................................................................................      703
        (b)...................................................................................      703
        (c)...................................................................................      703
        (d)...................................................................................      703
Section 314(a)................................................................................      704, 1018
        (b)...................................................................................      Not Applicable
        (c)(1)................................................................................      102, 401, 1204
        (c)(2)................................................................................      102, 401, 1204
        (c)(3)................................................................................      Not Applicable
        (d)...................................................................................      Not Applicable
        (e)...................................................................................      102
Section 315(a)................................................................................      601
        (b)...................................................................................      602
        (c)...................................................................................      601, 603
        (d)...................................................................................      601
        (e)...................................................................................      514
Section 316(a)(1)(A)..........................................................................      512
        (a)(1)(B).............................................................................      513
        (a)(2)................................................................................      Not Applicable
        (b)...................................................................................      508
        (c)...................................................................................      104
Section 317(a)(1).............................................................................      503
        (a)(2)................................................................................      504
        (b)...................................................................................      1003
Section 318(a)................................................................................      107
</TABLE>
<PAGE>   3

                               TABLE OF CONTENTS
                                  (continued)

<TABLE>
<CAPTION>
                                                                                 PAGE



<S>                                                                              <C>
RECITALS OF THE COMPANY.............................................................1

                                      ARTICLE ONE
                DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

SECTION 101.Definitions.............................................................1
         Acquired Debt..............................................................2
         Act    ....................................................................2
         Affiliate..................................................................2
         Authenticating Agent.......................................................2
         Bank Credit Agreement......................................................2
         Board of Directors.........................................................2
         Board Resolution...........................................................2
         Business Day...............................................................2
         Capital Lease Obligation...................................................2
         Capital Stock..............................................................3
         Change of Control..........................................................3
         Commission.................................................................3
         Common Equity..............................................................3
         Company....................................................................3
         Company Request or Company Order...........................................3
         Consolidated Net Worth.....................................................3
         Corporate Trust Office.....................................................3
         Corporation................................................................3
         Debt   ....................................................................3
         Default....................................................................4
         Defaulted Interest.........................................................4
         Depositary.................................................................4
         Disqualified Stock.........................................................4
         DTC    ....................................................................5
         Eagle River................................................................5
         Event of Default...........................................................5
         Exchange Act...............................................................5
         Expiration Date............................................................5
         Global Security............................................................5
         Guarantee..................................................................5
         Holder ....................................................................5
         Incur  ....................................................................5
         Indenture..................................................................6
         Interest Payment Date......................................................6
         Interest Rate or Currency Protection Agreement.............................6
         Investment.................................................................6
         Issue Date.................................................................6
         Joint Venture..............................................................6
         Lien   ....................................................................6
</TABLE>
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<PAGE>   4
                                TABLE OF CONTENTS
                                   (continued)

<TABLE>
<CAPTION>
                                                                                 PAGE


<S>                                                                              <C>
         Maturity...................................................................7
         Offer to Purchase..........................................................7
         Officers' Certificate......................................................9
         Opinion of Counsel.........................................................9
         Outstanding................................................................9
         Paying Agent..............................................................10
         Permitted Interest Rate or Currency Protection Agreement..................10
         Person....................................................................10
         Predecessor Security......................................................10
         Preferred Stock...........................................................10
         Purchase Date.............................................................10
         Purchase Money Debt.......................................................10
         Purchase Money Lien.......................................................11
         Receivables...............................................................11
         Receivables Sale..........................................................11
         Redemption Date...........................................................11
         Redemption Price..........................................................11
         Regular Record Date.......................................................11
         Required Consent..........................................................11
         Restricted Subsidiary.....................................................12
         SEC Reports...............................................................12
         Securities................................................................12
         Securities Act............................................................12
         Security Register and Security Registrar..................................12
         Significant Subsidiary....................................................12
         Special Record Date.......................................................12
         Stated Maturity...........................................................12
         Subsidiary................................................................12
         Telecommunications Assets.................................................12
         Telecommunications Business...............................................12
         Trustee...................................................................13
         Trust Indenture Act.......................................................13
         Unrestricted Subsidiary...................................................13
         Vendor Financing Facility.................................................13
         Vice President............................................................13
         Voting Stock..............................................................13
         Wholly-Owned Restricted Subsidiary........................................13

SECTION 102.Compliance Certificates and Opinions...................................13
SECTION 103.Form of Documents Delivered to Trustee.................................14
SECTION 104.Acts of Holders; Record Dates..........................................15
SECTION 105.Notices, Etc., to Trustee and Company..................................17
SECTION 106.Notice to Holders; Waiver..............................................17
SECTION 107.Conflict with Trust Indenture Act......................................17
</TABLE>

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                                TABLE OF CONTENTS
                                   (continued)

<TABLE>
<CAPTION>
                                                                                 PAGE


<S>                                                                              <C>
SECTION 108.Effect of Headings and Table of Contents...............................18
SECTION 109.Successors and Assigns.................................................18
SECTION 110.Separability Clause....................................................18
SECTION 111.Benefits of Indenture..................................................18
SECTION 112.Governing Law..........................................................18
SECTION 113.Legal Holidays.........................................................18

                                      ARTICLE TWO
                                    SECURITY FORMS

SECTION 201.Forms Generally........................................................18
SECTION 202.[intentionally omitted]................................................19
SECTION 203.[intentionally omitted]................................................19
SECTION 204.Additional Provisions Required in Global Security......................19
SECTION 205.Form of Trustee's Certificate of Authentication........................19

                                     ARTICLE THREE
                                    THE SECURITIES

SECTION 302.Denominations..........................................................22
SECTION 303.Execution, Authentication, Delivery and Dating.........................23
SECTION 304.Temporary Securities...................................................23
SECTION 305.Registration, Registration of Transfer and Exchange....................24
SECTION 306.Mutilated, Destroyed, Lost and Stolen Securities.......................25
SECTION 307.Payment of Interest; Interest Rights Preserved.........................26
SECTION 308.Persons Deemed Owners..................................................27
SECTION 309.Cancellation...........................................................27
SECTION 310.Computation of Interest................................................28
SECTION 311.CUSIP Numbers..........................................................28

                                     ARTICLE FOUR
                              SATISFACTION AND DISCHARGE

SECTION 401.Satisfaction and Discharge of Indenture................................28
SECTION 402.Application of Trust Money.............................................29

                                     ARTICLE FIVE
                                       REMEDIES

SECTION 501.Events of Default......................................................29
SECTION 502.Acceleration of Maturity; Rescission and Annulment.....................31
SECTION 503.Collection of Indebtedness and Suits for Enforcement by Trustee........32
SECTION 504.Trustee May File Proofs of Claim.......................................33
SECTION 505.Trustee May Enforce Claims Without Possession of Securities............34
SECTION 506.Application of Money Collected.........................................34
SECTION 507.Limitation on Suits....................................................34
SECTION 508.Unconditional Right of Holders to Receive Principal, Premium and
              Interest.............................................................35
SECTION 509.Restoration of Rights and Remedies.....................................35
</TABLE>


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                                TABLE OF CONTENTS
                                   (continued)

<TABLE>
<CAPTION>
                                                                                 PAGE


<S>                                                                              <C>
SECTION 510.Rights and Remedies Cumulative.........................................35
SECTION 511.Delay or Omission Not Waiver...........................................36
SECTION 512.Control by Holders.....................................................36
SECTION 513.Waiver of Past Defaults................................................36
SECTION 514.Undertaking for Costs..................................................37
SECTION 515.Waiver of Stay or Extension Laws.......................................37

                                      ARTICLE SIX
                                      THE TRUSTEE

SECTION 601.Certain Duties and Responsibilities....................................37
SECTION 602.Notice of Defaults.....................................................37
SECTION 603.Certain Rights of Trustee..............................................37
SECTION 604.Not Responsible for Recitals or Issuance of Securities.................38
SECTION 605.May Hold Securities....................................................39
SECTION 606.Money Held in Trust....................................................39
SECTION 607.Compensation and Reimbursement.........................................39
SECTION 608.Disqualification; Conflicting Interests................................40
SECTION 609.Corporate Trustee Required; Eligibility................................40
SECTION 610.Resignation and Removal; Appointment of Successor......................40
SECTION 611.Acceptance of Appointment by Successor.................................42
SECTION 612.Merger, Conversion, Consolidation or Succession to Business............43
SECTION 613.Preferential Collection of Claims Against the Company..................43
SECTION 614.Appointment of Authenticating Agent....................................43

                                     ARTICLE SEVEN
                 HOLDERS' LISTS AND REPORTS BY TRUSTEE AND THE COMPANY

SECTION 701.Company to Furnish Trustee Names and Addresses of Holders..............45
SECTION 702.Preservation of Information; Communications to Holders.................45
SECTION 703.Reports by Trustee.....................................................45
SECTION 704.Reports by Company.....................................................46

                                     ARTICLE EIGHT
                              MERGER, CONSOLIDATION, ETC.

SECTION 801.Mergers, Consolidations and Certain Sales of Assets....................46
SECTION 802.Successor Substituted..................................................47

                                     ARTICLE NINE
                                SUPPLEMENTAL INDENTURES

SECTION 901.Supplemental Indentures Without Consent of Holders.....................47
SECTION 902.Supplemental Indentures with Consent of Holders........................48
SECTION 903.Execution of Supplemental Indentures...................................49
SECTION 904.Effect of Supplemental Indentures......................................49
SECTION 905.Conformity with Trust Indenture Act....................................50
SECTION 906.Reference in Securities to Supplemental Indentures.....................50
</TABLE>

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                                TABLE OF CONTENTS
                                   (continued)

<TABLE>
<CAPTION>
                                                                                 PAGE


<S>                                                                              <C>

                                      ARTICLE TEN
                                       COVENANTS

SECTION 1001.Payment of Principal, Premium and Interest............................50
SECTION 1002.Maintenance of Office or Agency.......................................50
SECTION 1003.Money for Security Payments to be Held in Trust.......................51
SECTION 1004.Existence.............................................................52
SECTION 1005.Maintenance of Properties.............................................52
SECTION 1006.Payment of Taxes and Other Claims.....................................52
SECTION 1007.[intentionally omitted]...............................................53
SECTION 1008.[intentionally omitted]...............................................53
SECTION 1009.[intentionally omitted]...............................................53
SECTION 1010.[intentionally omitted]...............................................53
SECTION 1011.[intentionally omitted]...............................................53
SECTION 1012.[intentionally omitted]...............................................53
SECTION 1013.[intentionally omitted]...............................................53
SECTION 1014.[intentionally omitted]...............................................53
SECTION 1015.[intentionally omitted]...............................................53
SECTION 1016.Change of Control.....................................................53
SECTION 1017.Provision of Financial Information....................................54
SECTION 1018.Statement by Officers as to Default...................................54
SECTION 1019.Waiver of Certain Covenants...........................................55

                                         ARTICLE ELEVEN
                                    REDEMPTION OF SECURITIES

SECTION 1101.Applicability of Article..............................................55
SECTION 1102.Election to Redeem; Notice to Trustee.................................55
SECTION 1103.Selection by Trustee of Securities to be Redeemed.....................56
SECTION 1104.Notice of Redemption..................................................56
SECTION 1105.Deposit of Redemption Price...........................................57
SECTION 1106.Securities Payable on Redemption Date.................................57
SECTION 1107.Securities Redeemed in Part...........................................57

                                         ARTICLE TWELVE
                               DEFEASANCE AND COVENANT DEFEASANCE

SECTION 1201.Company's Option to Effect Defeasance or Covenant Defeasance..........58
SECTION 1202.Defeasance and Discharge..............................................58
SECTION 1203.Covenant Defeasance...................................................59
SECTION 1204.Conditions to Defeasance or Covenant Defeasance.......................59
SECTION 1205.Deposited Money and U.S. Government Obligations to Be Held in Trust;
               Other Miscellaneous Provisions......................................61
SECTION 1206.Reinstatement.........................................................62
</TABLE>

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      INDENTURE, dated as of ___________, 200__, between XO Communications,
Inc., a corporation organized under the laws of the State of Delaware (the
"Company"), having its principal office at 11111 Sunset Hills Road, Reston,
Virginia 20190, and _____________________, duly organized and existing under the
laws of _______________, as Trustee (herein called the "Trustee").

                             RECITALS OF THE COMPANY

      The Company has duly authorized the execution and delivery of this
Indenture to provide for the issuance from time to time of its unsecured
debentures, notes or other evidences of indebtedness (herein called the
"Securities"), to be issued in one or more series as provided in this Indenture.

      All things necessary to make the Securities, when executed by the Company
and authenticated and delivered hereunder and duly issued by the Company, the
valid obligations of the Company, and to make this Indenture a valid agreement
of the Company, in accordance with their and its terms, have been done.

                   NOW, THEREFORE, THIS INDENTURE WITNESSETH:

      For and in consideration of the premises and the purchase of the
Securities by the Holders thereof, it is mutually agreed, for the equal and
proportionate benefit of all Holders of the Securities or of series thereof, as
follows:

                                  ARTICLE ONE

                        DEFINITIONS AND OTHER PROVISIONS
                             OF GENERAL APPLICATION

SECTION 101.       Definitions.

      For all purposes of this Indenture, except as otherwise expressly provided
or unless the context otherwise requires:

            (1)    the terms defined in this Article have the meanings assigned
      to them in this Article and include the plural as well as the singular;

            (2)    all other terms used herein which are defined in the Trust
      Indenture Act, either directly or by reference therein, have the meanings
      assigned to them therein;

            (3)    all accounting terms not otherwise defined herein have the
      meanings assigned to them in accordance with generally accepted accounting
      principles (whether or not such is indicated herein) and, except as
      otherwise herein expressly provided, the term "generally accepted
      accounting principles" with respect to any computation required or
      permitted hereunder shall mean such accounting principles as are generally
      accepted as consistently applied by the Company at the date of such
      computation; and
<PAGE>   9

            (4)    the words "herein", "hereof" and "hereunder" and other words
      of similar import refer to this Indenture as a whole and not to any
      particular Article, Section or other subdivision.

Certain terms, used principally in Article Six, are defined in that Article.

      "Acquired Debt" means, with respect to any specified Person, (i) Debt of
any other Person existing at the time such Person merges with or into or
consolidates with or becomes a Restricted Subsidiary of such specified Person
and (ii) Debt secured by a Lien encumbering any asset acquired by such specified
Person, which Debt was not Incurred in anticipation of, and was outstanding
prior to, such merger, consolidation or acquisition.

      "Act", when used with respect to any Holder, has the meaning specified in
Section 104.

      "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 the purposes of this definition,
"control" when used with respect to any specified Person means the power to
direct the management and policies of such Person, directly or indirectly,
whether through the ownership of voting securities, by contract or otherwise;
and the terms "controlling" and "controlled" have meanings correlative to the
foregoing.

      "Authenticating Agent" means any Person authorized by the Trustee pursuant
to Section 614 to act on behalf of the Trustee to authenticate Securities of one
or more series.

      "Bank Credit Agreement" means any one or more credit agreements (which may
include or consist of revolving credits) between the Company or any Restricted
Subsidiary of the Company and one or more banks or other financial institutions
providing financing for the business of the Company and its Restricted
Subsidiaries.

      "Board of Directors" means either the board of directors of the Company or
any duly authorized committee of that board.

      "Board Resolution" means a copy of a resolution certified by the Secretary
or an Assistant Secretary of the Company to have been duly adopted by the Board
of Directors and to be in full force and effect on the date of such
certification, and delivered to the Trustee.

      "Business Day" means each Monday, Tuesday, Wednesday, Thursday and Friday
which is not a day on which banking institutions in The Borough of Manhattan,
The City of New York, New York are authorized or obligated by law or executive
order to close.

      "Capital Lease Obligation" of any Person means the obligation to pay rent
or other payment amounts under a lease of (or other Debt arrangements conveying
the right to use) real or personal property of such Person which is required to
be classified and accounted for as a capital lease or a liability on the face of
a balance sheet of such Person in accordance with generally accepted accounting
principles (a "Capital Lease"). The stated maturity of such obligation shall be
the date of the last payment of rent or any other amount due under such lease
prior to the first date upon which such lease may be terminated by the lessee
without payment of a penalty. The principal amount of such obligation shall be
the capitalized amount thereof that


                                      -2-
<PAGE>   10

would appear on the face of a balance sheet of such Person in accordance with
generally accepted accounting principles.

      "Capital Stock" of any Person means any and all shares, interests,
participations or other equivalents (however designated) of corporate stock or
other equity participations, including partnership interests, whether general or
limited, of such Person.

      "Change of Control" has the meaning specified in Section 1016.

      "Commission" means the Securities and Exchange Commission, as from time to
time constituted, created under the Exchange Act, or, if at any time after the
execution of this instrument such Commission is not existing and performing the
duties now assigned to it under the Trust Indenture Act, then the body
performing such duties at such time.

      "Common Equity" of any Person means Capital Stock of such Person that is
not Disqualified Stock, and a "sale of Common Equity" includes any sale of
Common Equity effected by private sale or public offering.

      "Company" means the Person named as the "Company" in the first paragraph
of this instrument until a successor Person shall have become such pursuant to
the applicable provisions of this Indenture and thereafter "Company" shall mean
such successor Person.

      "Company Request" or "Company Order" means a written request or order
signed in the name of the Company by (i) the Chief Executive Officer, the
President, an Executive Vice President or a Vice President of the Company, and
(ii) the Treasurer, Assistant Treasurer, Secretary or an Assistant Secretary of
the Company, and delivered to the Trustee.

      "Consolidated Net Worth" of any Person means the consolidated
stockholders' equity of such Person, determined on a consolidated basis in
accordance with generally accepted accounting principles, less amounts
attributable to Disqualified Stock of such Person; provided that, with respect
to the Company, adjustments following the date of this Indenture to the
accounting books and records of the Company in accordance with Accounting
Principles Board Opinions Nos. 16 and 17 (or successor opinions thereto) or
otherwise resulting from the acquisition of control of the Company by another
Person shall not be given effect to.

      "Corporate Trust Office" means the principal office of the Trustee in the
Borough of Manhattan, The City of New York, New York, at which at any particular
time its corporate trust business shall be administered, which at the date
hereof is located at _____________________________.

      "Corporation" means a corporation, association, company, limited liability
company, joint-stock company or business trust.

      "Debt" means (without duplication), with respect to any Person, whether
recourse is to all or a portion of the assets of such Person and whether or not
contingent, (i) every obligation of such Person for money borrowed, (ii) every
obligation of such Person evidenced by bonds, debentures, notes or other similar
instruments, including any such obligations Incurred in connection with the
acquisition of property, assets or businesses, (iii) every reimbursement


                                      -3-
<PAGE>   11


obligation of such Person with respect to letters of credit, bankers'
acceptances or similar facilities issued for the account of such Person, (iv)
every obligation of such Person issued or assumed as the deferred purchase price
of property or services (including securities repurchase agreements but
excluding trade accounts payable or accrued liabilities arising in the ordinary
course of business which are not overdue or which are being contested in good
faith), (v) every Capital Lease Obligation of such Person, (vi) all Receivables
Sales of such Person, together with any obligation of such Person to pay any
discount, interest, fees, indemnities, penalties, recourse, expenses or other
amounts in connection therewith, (vii) all obligations to redeem Disqualified
Stock issued by such Person, (viii) every obligation under Interest Rate or
Currency Protection Agreements of such Person and (ix) every obligation of the
type referred to in clauses (i) through (viii) of another Person and all
dividends of another Person the payment of which, in either case, such Person
has Guaranteed. The "amount" or "principal amount" of Debt at any time of
determination as used herein represented by (a) any Debt issued at a price that
is less than the principal amount at maturity thereof, shall be the amount of
the liability in respect thereof determined in accordance with generally
accepted accounting principles, (b) any Receivables Sale, shall be the amount of
the unrecovered capital or principal investment of the purchaser (other than the
Company or a Wholly-Owned Restricted Subsidiary of the Company) thereof,
excluding amounts representative of yield or interest earned on such investment,
(c) any Disqualified Stock, shall be the maximum fixed redemption or repurchase
price in respect thereof, (d) any Capital Lease Obligation, shall be determined
in accordance with the definition thereof, or (e) any Permitted Interest Rate or
Currency Protection Agreement, shall be zero. In no event shall Debt include any
liability for taxes.

      "Default" means an event that with the passing of time or the giving of
notice or both shall constitute an Event of Default.

      "Defaulted Interest" has the meaning specified in Section 307.

      "Depositary" means, with respect to Securities of any series or issued in
whole or in part in the form of one or more Global Securities, DTC for so long
as it shall be a clearing agency registered under the Exchange Act, or such
successor (which shall be a clearing agency registered under the Exchange Act)
as the Company shall designate from time to time in an Officers' Certificate
delivered to the Trustee.

      "Disqualified Stock" of any Person means, with respect to Securities of
any series, any Capital Stock of such Person (other than Capital Stock
outstanding on the Issue Date of that series) which, by its terms (or by the
terms of any security into which it is convertible or for which it is
exchangeable), or upon the happening of any event, matures or is mandatorily
redeemable, pursuant to a sinking fund obligation or otherwise, or is redeemable
at the option of the holder thereof, in whole or in part, on or prior to the
final Stated Maturity of the Securities of that series (or, if earlier, the date
as of which the Securities of that series have been paid in full); provided,
however, that any Preferred Stock which would not constitute Disqualified Stock
but for provisions thereof giving holders thereof the right to require the
Company to repurchase or redeem such Preferred Stock upon the occurrence of an
asset sale or a Change of Control occurring prior to the final Stated Maturity
of the Securities of that series shall not constitute Disqualified Stock with
respect to such series if the asset sale or change of control provisions
applicable to such Preferred Stock are no more favorable to the holders of such
Preferred Stock


                                      -4-
<PAGE>   12

than the provisions applicable to the Securities contained in Section 1016 as
may be modified in the manner provided as contemplated by Section 301 and such
Preferred Stock specifically provides that the Company will not repurchase or
redeem any such stock pursuant to such provisions prior to the Company's
repurchase of the Securities of such series as are required to be repurchased
pursuant to Section 1016.

      "DTC" means The Depository Trust Company.

      "Eagle River" means Eagle River Investments, L.L.C., a limited liability
company formed under the laws of the State of Washington.

      "Event of Default "has the meaning specified in Section 501.

      "Exchange Act" means the Securities Exchange Act of 1934, as amended (or
any successor act) and the rules and regulations thereunder.

      "Expiration Date" has the meaning set forth in the definition of "Offer to
Purchase" in this Section 101.

      "Global Security" means a Security in the form prescribed in Section 204
and as contemplated by Section 301, evidencing all or part of the Securities of
any series, issued to the Depositary or its nominee, and registered in the name
of such Depositary or its nominee.

      "Guarantee" by any Person means any obligation, contingent or otherwise,
of such Person guaranteeing, or having the economic effect of guaranteeing, any
Debt of any other Person (the "primary obligor") in any manner, whether directly
or indirectly, and including, without limitation, any obligation of such Person,
(i) to purchase or pay (or advance or supply funds for the purchase or payment
of) such Debt or to purchase (or to advance or supply funds for the purchase of)
any security for the payment of such Debt, (ii) to purchase property, securities
or services for the purpose of assuring the holder of such Debt of the payment
of such Debt, or (iii) to maintain working capital, equity capital or other
financial statement condition or liquidity of the primary obligor so as to
enable the primary obligor to pay such Debt (and "Guaranteed", "Guaranteeing"
and "Guarantor" shall have meanings correlative to the foregoing); provided,
however, that the Guarantee by any Person shall not include endorsements by such
Person for collection or deposit, in either case, in the ordinary course of
business; and provided, further, that the incurrence by a Restricted Subsidiary
of the Company of a Purchase Money Lien shall not be deemed to constitute a
Guarantee by such Restricted Subsidiary.

      "Holder" means a Person in whose name a Security is registered in the
Security Register.

      "Incur" means, with respect to any Debt or other obligation of any Person,
to create, issue, incur (by conversion, exchange or otherwise), assume,
Guarantee or otherwise become liable in respect of such Debt or other obligation
including by acquisition of Subsidiaries or the recording, as required pursuant
to generally accepted accounting principles or otherwise, of any such Debt or
other obligation on the balance sheet of such Person (and "Incurrence",
"Incurred", "Incurrable" and "Incurring" shall have meanings correlative to the
foregoing); provided, however, that a change in generally accepted accounting
principles that results in an obligation of such Person that exists at such time
becoming Debt shall not be deemed an Incurrence of such


                                      -5-
<PAGE>   13


Debt and that neither the accrual of interest nor the accretion of original
issue discount shall be deemed an Incurrence of Debt; provided, further,
however, that the Company may elect to treat all or any portion of revolving
credit debt of the Company or a Subsidiary as being incurred from and after any
date beginning the date the revolving credit commitment is extended to the
Company or a Subsidiary, by furnishing notice thereof to the Trustee, and any
borrowings or reborrowings by the Company or a Subsidiary under such commitment
up to the amount of such commitment designated by the Company as Incurred shall
not be deemed to be new Incurrences of Debt by the Company or such Subsidiary.

      "Indenture" means this instrument as originally executed or as it may from
time to time be supplemented or amended by one or more indentures supplemental
hereto entered into pursuant to the applicable provisions hereof, including, for
all purposes of this instrument and any such supplemental indenture, the
provisions of the Trust Indenture Act that are deemed to be a part of and govern
this instrument and any such supplemental indenture, respectively. The term
"Indenture" shall also include the terms of particular series of Securities
established as contemplated by Section 301.

      "Interest Payment Date" when used with respect to any installment of
interest on a Security of any series means the date specified in such Security
on which such installment of interest is due and payable.

      "Interest Rate or Currency Protection Agreement" of any Person means any
forward contract, futures contract, swap, option or other financial agreement or
arrangement (including, without limitation, caps, floors, collars and similar
agreements) relating to, or the value of which is dependent upon, interest rates
or currency exchange rates or indices.

      "Investment" by any Person means any direct or indirect loan, advance or
other extension of credit or capital contribution (by means of transfers of cash
or other property to others or payments for property or services for the account
or use of others, or otherwise) to, or purchase or acquisition of Capital Stock,
bonds, notes, debentures or other securities or evidence of Debt issued by, any
other Person, including any payment on a Guarantee of any obligation of such
other Person, but excluding any loan, advance or extension of credit to an
employee of the Company or any of its Restricted Subsidiaries in the ordinary
course of business, accounts receivable and other commercially reasonable
extensions of trade credit.

      "Issue Date" means, with respect to Securities of any series, the date on
which the Securities of that series are first authenticated and delivered under
this Indenture.

      "Joint Venture" means a corporation, partnership or other entity engaged
in one or more Telecommunications Businesses as to which the Company (directly
or through one or more Restricted Subsidiaries) exercises managerial control and
in which the Company owns (i) a 50% or greater interest, or (ii) a 30% or
greater interest, together with options or other contractual rights, exercisable
not more than seven years after the Company's initial Investment in such Joint
Venture, to increase its interest to not less than 50%.

      "Lien" means, with respect to any property or assets, any mortgage or deed
of trust, pledge, hypothecation, assignment, Receivables Sale, deposit
arrangement, security interest, lien,


                                      -6-
<PAGE>   14

charge, easement (other than any easement not materially impairing usefulness or
marketability), encumbrance, preference, priority or other security agreement or
preferential arrangement of any kind or nature whatsoever on or with respect to
such property or assets (including, without limitation, any conditional sale or
other title retention agreement having substantially the same economic effect as
any of the foregoing).

      "Maturity", when used with respect to any Security, means the date on
which the principal of such Security or as installment of principal becomes due
and payable as therein or herein provided, whether at the Stated Maturity or by
declaration of acceleration, call for repurchase, call for redemption or
otherwise.

      "Offer to Purchase" means a written offer (the "Offer") sent by the
Company by first class mail, postage prepaid, to each Holder of Securities of a
particular series at his address appearing in the Security Register on the date
of the Offer offering to purchase up to the principal amount of Securities of
that series specified in such Offer at the purchase price specified in such
Offer (as determined pursuant to this Indenture). Unless otherwise required by
applicable law, the Offer shall specify an expiration date (the "Expiration
Date") of the Offer to Purchase which shall be, subject to any contrary
requirements of applicable law, not less than 30 days or more than 60 days after
the date of such Offer and a settlement date (the "Purchase Date") for purchase
of Securities within five Business Days after the Expiration Date. The Company
shall notify the Trustee at least 15 Business Days (or such shorter period as is
acceptable to the Trustee) prior to the mailing of the Offer of the Company's
obligation to make an Offer to Purchase, and the Offer shall be mailed by the
Company or, at the Company's request, by the Trustee in the name and at the
expense of the Company. The Offer shall contain information concerning the
business of the Company and its Subsidiaries which the Company in good faith
believes will enable such Holders to make an informed decision with respect to
the Offer to Purchase (which at a minimum will include (i) the most recent
annual and quarterly financial statements and "Management's Discussion and
Analysis of Financial Condition and Results of Operations" contained in the
documents required to be filed with the Trustee pursuant to this Indenture
(which requirements may be satisfied by delivery of such documents together with
the Offer), (ii) a description of material developments in the Company's
business subsequent to the date of the latest of such financial statements
referred to in clause (i) (including a description of the events requiring the
Company to make the Offer to Purchase), (iii) if applicable, appropriate pro
forma financial information concerning the Offer to Purchase and the events
requiring the Company to make the Offer to Purchase and (iv) any other
information required by applicable law to be included therein). The Offer shall
contain all instructions and materials necessary to enable such Holders to
tender Securities pursuant to the Offer to Purchase. The Offer shall also state:

            (a)    the Section of this Indenture pursuant to which the Offer to
      Purchase is being made and the series of Securities to which the Offer to
      Purchase relates;

            (b)    the Expiration Date and the Purchase Date;

            (c)    the aggregate principal amount of Outstanding Securities of
      that series offered to be purchased by the Company pursuant to the Offer
      to Purchase (including, if


                                      -7-
<PAGE>   15

      less than 100%, the manner by which such has been determined pursuant
      Section 1016) (the "Purchase Amount");

            (d)    the purchase price to be paid by the Company for each $1,000
      aggregate principal amount of Securities of that series accepted for
      payment (as specified pursuant to this Indenture) (the "Purchase Price");

            (e)    that the Holder may tender all or any portion of the
      Securities of that series registered in the name of such Holder and that
      any portion of any such Security tendered must be tendered in an integral
      multiple of $1,000 principal amount;

            (f)    the place or places where Securities are to be surrendered
      for tender pursuant to the Offer to Purchase;

            (g)    that interest on any Security of that series not tendered or
      tendered but not purchased by the Company pursuant to the Offer to
      Purchase will continue to accrue;

            (h)    that on the Purchase Date the Purchase Price will become due
      and payable upon each Security being accepted for payment pursuant to the
      Offer to Purchase and that interest thereon shall cease to accrue on and
      after the Purchase Date;

            (i)    that each Holder electing to tender a Security pursuant to
      the Offer to Purchase will be required to surrender such Security at the
      place or places specified in the Offer prior to the close of business on
      the Expiration Date (such Security being, if the Company or the Trustee so
      requires, duly endorsed by, or accompanied by a written instrument of
      transfer in form satisfactory to the Company and the Trustee duly executed
      by, the Holder thereof or his attorney duly authorized in writing);

            (j)    that Holders of tendered Securities will be entitled to
      withdraw all or any portion of Securities tendered if the Company (or its
      Paying Agent) receives, not later than the close of business on the
      Expiration Date, a telegram, telex, facsimile transmission or letter
      setting forth the name of the Holder, the principal amount of the Security
      the Holder tendered, the certificate number and series of the Security the
      Holder tendered and a statement that such Holder is withdrawing all or a
      portion of his tender;

            (k)    that (a) if Securities of such series in an aggregate
      principal amount less than or equal to the Purchase Amount are duly
      tendered and not withdrawn pursuant to the Offer to Purchase, the Company
      shall purchase all such Securities and (b) if Securities of such series in
      an aggregate principal amount in excess of the Purchase Amount are
      tendered and not withdrawn pursuant to the Offer to Purchase, the Company
      shall purchase Securities of such series having an aggregate principal
      amount equal to the Purchase Amount on a pro rata basis (with such
      adjustments as may be deemed appropriate so that only Securities in
      denominations of $1,000 or integral multiples thereof shall be purchased);

            (l)    that in the case of any Holder whose Security is purchased
      only in part, the Company shall execute, and the Trustee shall
      authenticate and deliver to the Holder of such Security without service
      charge, a new Security or Securities of the same series of


                                      -8-
<PAGE>   16

      any authorized denomination as requested by such Holder, in an aggregate
      principal amount equal to and in exchange for the unpurchased portion of
      the Security so tendered; and

            (m)    the CUSIP number or numbers of the Securities offered to be
      purchased by the Company pursuant to the Offer to Purchase.

Any Offer to Purchase shall be governed by and effected in accordance with the
Offer for such Offer to Purchase.

      "Officers' Certificate" means a certificate signed by (i) the Chief
Executive Officer, President, an Executive Vice President or a Vice President,
and (ii) the Treasurer, Assistant Treasurer, Secretary or an Assistant
Secretary, of the Company, and delivered to the Trustee and containing the
statements provided for in Section 102. One of the officers signing an Officers'
Certificate given pursuant to Section 1018 shall be the principal executive,
financial or accounting officer of the Company.

      "Opinion of Counsel" means a written opinion of legal counsel, who may be
counsel for the Company, and who shall be acceptable to the Trustee, and
containing the statements provided for in Section 102.

      "Outstanding", when used with respect to Securities of any series, means,
as of the date of determination, all Securities of that series theretofore
authenticated and delivered under this Indenture, except:

            (i)    Securities theretofore cancelled by the Trustee or delivered
      to the Trustee for cancellation;

            (ii)   Securities for whose payment or redemption money in the
      necessary amount has been theretofore deposited with the Trustee or any
      Paying Agent (other than the Company) in trust or set aside and segregated
      in trust by the Company (if the Company shall act as its own Paying Agent)
      for the Holders of such Securities; provided that, if such Securities are
      to be redeemed, notice of such redemption has been duly given pursuant to
      this Indenture or provision therefor satisfactory to the Trustee has been
      made; and

            (iii)  Securities which have been paid pursuant to Section 306 or in
      exchange for or in lieu of which other Securities have been authenticated
      and delivered pursuant to this Indenture, other than any such Securities
      of that series in respect of which there shall have been presented to the
      Trustee proof satisfactory to it that such Securities are held by a bona
      fide purchaser in whose hands such Securities are valid obligations of the
      Company;

provided, however, that in determining whether the Holders of the requisite
principal amount of Outstanding Securities of any series have given any request,
demand, authorization, direction, notice, consent or waiver hereunder,
Securities owned by the Company or any other obligor upon the Securities or any
Affiliate of the Company or of such other obligor shall be disregarded and
deemed not to be Outstanding, except that, in determining whether the Trustee
shall be protected

                                      -9-
<PAGE>   17

in relying upon any such request, demand, authorization, direction, notice,
consent or waiver, only Securities which the Trustee knows to be so owned shall
be so disregarded. Securities of that series so owned which have been pledged in
good faith may be regarded as Outstanding if the pledgee establishes to the
satisfaction of the Trustee the pledgee's right so to act with respect to such
Securities and that the pledgee is not the Company or any other obligor upon the
Securities of that series or any Affiliate of the Company or of such other
obligor.

      "Paying Agent" means any Person authorized by the Company to pay the
principal of (and premium, if any) or interest on any Securities on behalf of
the Company. The Trustee is hereby authorized by the Company to act as a "Paying
Agent" for the purposes of this Indenture, until such time as the Company
notifies the Trustee in writing that such authorization is revoked.

      "Permitted Interest Rate or Currency Protection Agreement" of any Person
means any Interest Rate or Currency Protection Agreement entered into with one
or more financial institutions in the ordinary course of business that is
designed to protect such Person against fluctuations in interest rates or
currency exchange rates with respect to Debt Incurred and which shall have a
notional amount no greater than the payments due with respect to the Debt being
hedged thereby and not for purposes of speculation.

      "Person" means any individual, corporation, partnership, limited liability
company, joint venture, association, joint stock company, trust, unincorporated
organization, or government or any agency or political subdivision thereof or
any other entity.

      "Predecessor Security" of any particular Security means every previous
Security issued before, and evidencing all or a portion of the same debt as that
evidenced by, such particular Security; and, for the purposes of this
definition, any Security authenticated and delivered under Section 306 in
exchange for or in lieu of a mutilated, destroyed, lost or stolen Security shall
be deemed to evidence the same debt as the mutilated, destroyed, lost or stolen
Security.

      "Preferred Stock" of any Person means Capital Stock of such Person of any
class or classes (however designated) that ranks prior, as to the payment of
dividends or as to the distribution of assets upon any voluntary or involuntary
liquidation, dissolution or winding up of such Person, to shares of Capital
Stock of any other class of such Person.

      "Purchase Date" has the meaning set forth in the definition of "Offer to
Purchase" in this Section 101.

      "Purchase Money Debt" means (i) Acquired Debt Incurred in connection with
the acquisition of Telecommunications Assets and (ii) Debt of the Company or of
any Restricted Subsidiary of the Company (including, without limitation, Debt
represented by Bank Credit Agreements, Capital Lease Obligations, Vendor
Financing Facilities, mortgage financings and purchase money obligations)
Incurred for the purpose of financing all or any part of the cost of
construction, acquisition or improvement by the Company or any Restricted
Subsidiary of the Company or any Joint Venture of any Telecommunications Assets
of the Company, any Restricted Subsidiary of the Company or any Joint Venture,
and including any related notes, Guarantees, collateral documents, instruments
and agreements executed in connection therewith, as the same may be amended,
supplemented, modified or restated from time to time.

                                      -10-
<PAGE>   18

      "Purchase Money Lien" means, with respect to Securities of any series,
Liens on real or personal property of the Company or a Restricted Subsidiary of
the Company acquired, constructed or constituting improvements made after the
Issue Date of that series to secure Purchase Money Debt which is Incurred for
the construction, acquisition and improvement of Telecommunications Assets and
is otherwise permitted under this Indenture, provided, however, that

            (a)    the net proceeds of any Debt secured by such a Lien does not
      exceed 100% of such purchase price or cost of construction or improvement
      of the property subject to such Lien,

            (b)    such Lien attaches to such property prior to, at the time of
      or within 180 days after the acquisition, completion of construction or
      commencement of operation of such property and

            (c)    such Lien does not extend to or cover any property other than
      the property (or identifiable portions thereof) acquired, constructed or
      constituting the improvements made with the proceeds of such Purchase
      Money Debt (it being understood and agreed that all Debt owed to any
      single lender or group of lenders or outstanding under any single credit
      facility shall be considered a single Purchase Money Debt, whether drawn
      at one time or from time to time);

      "Receivables" means receivables, chattel paper, instruments, documents or
intangibles evidencing or relating to the right to payment of money in respect
of the sale of goods or services.

      "Receivables Sale" of any Person means any sale of Receivables of such
Person (pursuant to a purchase facility or otherwise), other than in connection
with a disposition of the business operations of such Person relating thereto or
a disposition of defaulted Receivables for purpose of collection and not as a
financing arrangement.

      "Redemption Date", when used with respect to any Security to be redeemed,
means the date fixed for such redemption by or pursuant to this Indenture.

      "Redemption Price", when used with respect to any Security to be redeemed,
means the price at which it is to be redeemed pursuant to this Indenture.

      "Regular Record Date" for the interest payable on any Interest Payment
Date on the Securities of any series means the date specified for that purpose
as contemplated by Section 301.

      "Required Consent" means, except as otherwise expressly provided in this
Indenture with respect to matters requiring the consent of each Holder of
Securities affected thereby: (i) the consent of Holders of not less than a
majority in aggregate principal amount at Stated Maturity of Securities of any
series for any action relating to that series to (x) direct the time, method and
place of conducting any proceeding for any remedy available to the Trustee, or
exercising any power conferred upon such Trustee, or (y) consent to or waive, on
behalf of the Holders of all the Securities of that series, any past default and
its consequences, and (ii) with respect to all other


                                      -11-
<PAGE>   19
actions requiring the consent of holders of Securities of any series, the
consent of either (x) the Holders of a majority in aggregate principal amount at
Stated Maturity of the Securities of that series or, (y) voting together as a
single class,  the Holders of a majority in aggregate principal amount at Stated
Maturity of (I) the Securities of that series, (II) the Securities of each other
series whose Holders are being requested to consent to such action with respect
to the terms of that series or this Indenture, (III) the securities of each
series issued under the Indenture filed as Exhibit 4.2 to the Company's
Registration Statement on Form S-3 (Reg. No. 333- ______), filed with the
Commission on February 1, 2001, if the Holders of such securities are being
requested to consent to such action with respect to the terms of such series or
that Indenture, and (IV) any other class of debt securities issued by the
Company, if such debt securities or the indenture pursuant to which such debt
securities were issued both (A) require the consent of the Holders of such debt
securities to such action and (B) provide that the holders thereof will vote
with the Holders of Securities of any series with respect to such action.

      "Restricted Subsidiary" of the Company means any Subsidiary, whether
existing on or after the date of this Indenture, unless such Subsidiary is an
Unrestricted Subsidiary.

      "SEC Reports" has the meaning specified in Section 704.

      "Securities" has the meaning specified in the second paragraph of this
instrument.

      "Securities Act" means the Securities Act of 1933 and any statute
successor thereto, in each case as amended from time to time.

      "Security Register" and "Security Registrar" have the respective meanings
specified in Section 305.

      "Significant Subsidiary" means a Restricted Subsidiary that is a
"significant subsidiary" as defined in Rule 1-02(w) of Regulation S-X under the
Securities Act and the Exchange Act.

      "Special Record Date" for the payment of any Defaulted Interest means a
date fixed by the Trustee pursuant to Section 307.

      "Stated Maturity", when used with respect to any Security or any
installment of principal thereon, means the date specified in such Security as
the fixed date on which the principal of such Security or such installment of
principal is due and payable.

      "Subsidiary" of any Person means (i) a corporation more than 50% of the
combined voting power of the outstanding Voting Stock of which is owned,
directly or indirectly, by such Person or by one or more other Subsidiaries of
such Person or by such Person and one or more Subsidiaries thereof or (ii) any
other Person (other than a corporation) in which such Person, or one or more
other Subsidiaries of such Person or such Person and one or more other
Subsidiaries thereof, directly or indirectly, has at least a majority ownership
and power to direct the policies, management and affairs thereof.

      "Telecommunications Assets" means all assets, rights (contractual or
otherwise) and properties, whether tangible or intangible, used or intended for
use in connection with a Telecommunications Business.

      "Telecommunications Business" means, with respect to Securities of any
series, the business of (i) transmitting, or providing services relating to the
transmission of, voice, video or data through owned or leased transmission
facilities, (ii) creating, developing or marketing


                                      -12-
<PAGE>   20

communications related network equipment, software and other devices for use in
a Telecommunication Business or (iii) evaluating, participating or pursuing any
other activity or opportunity that is primarily related to those identified in
(i) or (ii) above and shall, in any event, include all businesses in which the
Company or any of its Subsidiaries are engaged on the Issue Date of that series;
provided that the determination of what constitutes a Telecommunications
Business shall be made in good faith by the Board of Directors, which
determination shall be conclusive.

      "Trustee" means the Person named as the "Trustee" in the first paragraph
of this instrument until a successor Trustee shall have become such pursuant to
the applicable provisions of this Indenture, and thereafter "Trustee" shall mean
or include each Person who is then a Trustee hereunder, and if at any time there
is more than one such Person, "Trustee" as used with respect to the Securities
of any series shall mean the Trustee with respect to Securities of that series.

      "Trust Indenture Act" means the Trust Indenture Act of 1939 as in force at
the date as of which this instrument was executed; provided, however, that in
the event the Trust Indenture Act of 1939 is amended after such date, "Trust
Indenture Act" means, to the extent required by any such amendment, the Trust
Indenture Act of 1939 as so amended.

      "Unrestricted Subsidiary" will have the meaning given to it in an
indenture supplemental hereto.

      "Vendor Financing Facility" means any agreements between the Company or a
Restricted Subsidiary of the Company and one or more vendors or lessors of
equipment or other capital assets to the Company or any of its Restricted
Subsidiaries (or any affiliate of any such vendor or lessor) providing financing
for the acquisition by the Company or any such Restricted Subsidiary of
equipment or other capital assets from any such vendor or lessor.

      "Vice President", when used with respect to the Company or the Trustee,
means any vice president, whether or not designated by a number or a word or
words added before or after the title "vice president".

      "Voting Stock" of any Person means Capital Stock of such Person which
ordinarily has voting power for the election of directors (or persons performing
similar functions) of such Person, whether at all times or only so long as no
senior class of securities has such voting power by reason of any contingency.

      "Wholly-Owned Restricted Subsidiary" of any Person means a Restricted
Subsidiary of such Person 99% or more 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 102.       Compliance Certificates and Opinions.

      Upon any application or request by the Company to the Trustee to take any
action under any provision of this Indenture, the Company shall furnish to the
Trustee such certificates and


                                      -13-
<PAGE>   21

opinions as may be required under the Trust Indenture Act and under this
Indenture. Each such certificate or opinion shall be given in the form of an
Officers' Certificate, if to be given by an officer of the Company, or an
Opinion of Counsel, if to be given by counsel, and shall comply with the
requirements of the Trust Indenture Act and any other requirement set forth in
this Indenture.

      Every certificate or opinion with respect to compliance with a condition
or covenant provided for in this Indenture (except for certificates provided for
in Section 1018) shall include

            (1)    a statement that each individual signing such certificate or
      opinion has read such covenant or condition and the definitions herein
      relating thereto;

            (2)    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;

            (3)    a statement that, in the opinion of each such individual, he
      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 complied with; and

            (4)    a statement as to whether, in the opinion of each such
      individual, such condition or covenant has been complied with.

SECTION 103.       Form of Documents Delivered to Trustee.

      In any case where several matters are required to be certified by, or
covered by an opinion of, any specified Person, it is not necessary that all
such matters be certified by, or covered by the opinion of, only one such
Person, or that they be so certified or covered by only one document, but one
such Person may certify or give an opinion with respect to some matters and one
or more other such Persons as to other matters, and any such Person may certify
or give an opinion as to such matters in one or several documents.

      Any certificate or opinion of an officer of the Company may be based,
insofar as it relates to legal matters, upon a certificate or opinion of, or
representations by, counsel, unless such officer knows, or in the exercise of
reasonable care should know, that the certificate or opinion or representations
with respect to the matters upon which his certificate or opinion is based are
erroneous. Any such certificate or opinion of counsel may be based, insofar as
it relates to factual matters, upon a certificate or opinion of, or
representations by, an officer or officers of the Company stating that the
information with respect to such factual matters is in the possession of the
Company, unless such counsel knows, or in the exercise of reasonable care should
know, that the certificate or opinion or representations with respect to such
matters are erroneous.

      Where any Person is required to make, give or execute two or more
applications, requests, consents, certificates, statements, opinions or other
instruments under this Indenture, they may, but need not, be consolidated and
form one instrument.

                                      -14-

<PAGE>   22
SECTION 104.   Acts of Holders; Record Dates.

      Any request, demand, authorization, direction, notice, consent, waiver
or other action provided by this Indenture to be given or taken by Holders may
be embodied in and evidenced by one or more instruments of substantially similar
tenor signed by such Holders in person or by agent duly appointed in writing;
and, except as herein otherwise expressly provided, such action shall become
effective when such instrument or instruments are delivered to the Trustee and,
where it is hereby expressly required, to the Company. Such instrument or
instruments (and the action embodied therein and evidenced thereby) are herein
sometimes referred to as the "Act" of the Holders signing such instrument or
instruments. Proof of execution of any such instrument or of a writing
appointing any such agent shall be sufficient for any purpose of this Indenture
and (subject to Section 601) conclusive in favor of the Trustee and the Company,
if made in the manner provided in this Section.

      The fact and date of the execution by any Person of any such instrument
or writing pursuant to this Section 104 may be proved by the affidavit of a
witness of such execution or by a certificate of a notary public or other
officer authorized by law to take acknowledgments of deeds, certifying that the
individual signing such instrument or writing acknowledged to him the execution
thereof. Where such execution is by a signer acting in a capacity other than his
individual capacity, such certificate or affidavit shall also constitute
sufficient proof of his authority. The fact and date of the execution of any
such instrument or writing, or the authority of the Person executing the same,
may also be proved in any other manner which the Trustee deems sufficient.

      The ownership of Securities shall be proved by the Security Register.

      Any request, demand, authorization, direction, notice, consent, waiver
or other Act of the Holder of any Security shall bind every future Holder of the
same Security and the Holder of every Security issued upon the registration of
transfer thereof or in exchange therefor or in lieu thereof in respect of
anything done, omitted or suffered to be done by the Trustee or the Company in
reliance thereon, whether or not notation of such action is made upon such
Security.

      The Company may set any day as a record date for the purpose of
determining the Holders of Outstanding Securities of any series entitled to
give, make or take any request, demand, authorization, direction, notice,
consent, waiver or other action provided or permitted by this Indenture to be
given, made or taken by Holders of Securities of such series, provided that the
Company may not set a record date for, and the provisions of this paragraph
shall not apply with respect to, the giving or making of any notice,
declaration, request or direction referred to in the next paragraph. If not set
by the Company prior to the first solicitation of a Holder made by any Person in
respect of any such matter referred to in the foregoing sentence, the record
date for any such matter shall be the 30th day (or, if later, the date of the
most recent list of Holders required to be provided pursuant to Section 701)
prior to such first solicitation. If any record date is set pursuant to this
paragraph, the Holders of Outstanding Securities of the relevant series on such
record date, and no other Holders, shall be entitled to take the relevant
action, whether or not such Holders remain Holders after such record date;
provided that no such action shall be effective hereunder unless taken on or
prior to the applicable Expiration Date by Holders of the requisite principal
amount of Outstanding Securities of the relevant series on such


                                      -15-
<PAGE>   23

record date. Nothing in this paragraph shall be construed to prevent the Company
from setting a new record date for any action for which a record date has
previously been set pursuant to this paragraph (whereupon the record date
previously set shall automatically and with no action by any Person be cancelled
and of no effect), and nothing in this paragraph shall be construed to render
ineffective any action taken by Holders of the requisite principal amount of
Outstanding Securities of the relevant series on the date such action is taken.
Promptly after any record date is set pursuant to this paragraph, the Company,
at its own expense, shall cause notice of such record date, the proposed action
by Holders and the applicable Expiration Date to be given to the Trustee in
writing and to each Holder of Securities of the relevant series in the manner
set forth in Section 106.

      The Trustee may set any day as a record date for the purpose of
determining the Holders of Outstanding Securities of any series entitled to join
in the giving or making of (i) any Notice of Default, (ii) any declaration of
acceleration referred to in Section 502, (iii) any request to institute
proceedings referred to in Section 507(2) or (iv) any direction referred to in
Section 512, in each case with respect to Securities of such series or (v) the
Required Consent. If any record date is set pursuant to this paragraph, the
Holders of Outstanding Securities of such series on such record date, and no
other Holders, shall be entitled to join in such notice, declaration, request or
direction, whether or not such Holders remain Holders after such record date;
provided that no such action shall be effective hereunder unless taken on or
prior to the applicable Expiration Date by Holders of the requisite principal
amount of Outstanding Securities of such series on such record date. Nothing in
this paragraph shall be construed to prevent the Trustee from setting a new
record date for any action for which a record date has previously been set
pursuant to this paragraph (whereupon the record date previously set shall
automatically and with no action by any Person be cancelled and of no effect),
and nothing in this paragraph shall be construed to render ineffective any
action taken by Holders of the requisite principal amount of Outstanding
Securities of the relevant series on the date such action is taken. Promptly
after any record date is set pursuant to this paragraph, the Trustee, at the
Company's expense, shall cause notice of such record date, the proposed action
by Holders and the applicable Expiration Date to be given to the Company in
writing and to each Holder of Securities of the relevant series in the manner
set forth in Section 106.

        With respect to any record date set pursuant to this Section, the party
hereto which sets such record dates may designate any day as the "Expiration
Date" and from time to time may change the Expiration Date to any earlier or
later day; provided that no such change shall be effective unless notice of the
proposed new Expiration Date is given to the other party hereto in writing, and
to each Holder of Securities of the relevant series in the manner set forth in
Section 106, on or prior to the existing Expiration Date. If an Expiration Date
is not designated with respect to any record date set pursuant to this Section,
the party hereto which set such record date shall be deemed to have initially
designated the 180th day after such record date as the Expiration Date with
respect thereto, subject to its right to change the Expiration Date as provided
in this paragraph. Notwithstanding the foregoing, no Expiration Date shall be
later than the 180th day after the applicable record date.

        Without limiting the foregoing, a Holder entitled hereunder to take any
action hereunder with regard to any particular Security may do so with regard to
all or any part of the principal


                                      -16-
<PAGE>   24

amount of such Security or by one or more duly appointed agents each of which
may do so pursuant to such appointment with regard to all or any part of such
principal amount.

SECTION 105.   Notices, Etc., to Trustee and Company.

      Any request, demand, authorization, direction, notice, consent, waiver
or Act of Holders or other document provided or permitted by this Indenture to
be made upon, given or furnished to, or filed with,

             (1)    the Trustee by any Holder or by the Company shall be
      sufficient for every purpose hereunder if delivered in writing to the
      Trustee at its Corporate Trust Office, Attention: Corporate Trust
      Administration, or

             (2)    the Company by the Trustee or by any Holder shall be
      sufficient for every purpose hereunder (unless otherwise herein expressly
      provided) if in writing and mailed, first-class postage prepaid, to the
      Company addressed to the Company at the address of its principal office
      specified in the first paragraph of this instrument or at any other
      address previously furnished in writing to the Trustee by the Company.

SECTION 106.   Notice to Holders; Waiver.

      Where this Indenture provides for notice to Holders of any event, such
notice shall be sufficiently given (unless otherwise herein expressly provided)
if (i) in the case of a Global Security, in writing by facsimile and/or by
overnight mail to the Depositary, and (ii) in the case of Securities other than
Global Securities, in writing and mailed, first-class postage prepaid, to each
Holder affected by such event, at his address as it appears in the Security
Register, not later than the latest date (if any), and not earlier than the
earliest date (if any), prescribed for the giving of such notice. In any case
where notice to Holders is given by mail, neither the failure to mail such
notice, nor any defect in any notice so mailed, to any particular Holder shall
affect the sufficiency of such notice with respect to other Holders. Where this
Indenture provides for notice in any manner, such notice may be waived in
writing by the Person entitled to receive such notice, either before or after
the event, and such waiver shall be the equivalent of such notice. Waivers of
notice by Holders shall be filed with the Trustee, but such filing shall not be
a condition precedent to the validity of any action taken in reliance upon such
waiver.

      In case by reason of the suspension of regular mail service or by reason
of any other cause it shall be impracticable to give such notice by mail, then
such notification as shall be made with the approval of the Trustee shall
constitute a sufficient notification for every purpose hereunder.

SECTION 107.   Conflict with Trust Indenture Act.

      If any provision hereof limits, qualifies or conflicts with a provision
of the Trust Indenture Act that is required under such Act to be a part of and
govern this Indenture, the latter provision shall control. If any provision of
this Indenture modifies or excludes any provision of the Trust Indenture Act
that may be so modified or excluded, the latter provision shall be deemed to
apply to this Indenture as so modified or to be excluded, as the case may be.

                                      -17-
<PAGE>   25

SECTION 108.   Effect of Headings and Table of Contents.

      The Article and Section headings herein and the Table of Contents are
for convenience only and shall not affect the construction hereof.

SECTION 109.   Successors and Assigns.

      All covenants and agreements in this Indenture by the Company shall bind
its successors and assigns, whether so expressed or not.

SECTION 110.   Separability Clause.

      In case any provision in this Indenture or in the Securities 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 111.   Benefits of Indenture.

      Nothing in this Indenture or in the Securities, express or implied,
shall give to any Person, other than the parties hereto and their successors
hereunder and the Holders of Securities, any benefit or any legal or equitable
right, remedy or claim under this Indenture.

SECTION 112.   Governing Law.

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

SECTION 113.   Legal Holidays.

      In any case where any Interest Payment Date, Redemption Date, Purchase
Date or Stated Maturity of any Security shall not be a Business Day, then
(notwithstanding any other provision of this Indenture or of the Securities)
payment of interest or principal (and premium, if any) need not be made on such
date, but may be made on the next succeeding Business Day with the same force
and effect as if made on the Interest Payment Date, Redemption Date, Purchase
Date or at the Stated Maturity, provided that no interest shall accrue for the
period from and after such Interest Payment Date, Redemption Date, Purchase Date
or Stated Maturity, as the case may be.

                                  ARTICLE TWO

                                 SECURITY FORMS

SECTION 201.   Forms Generally.

      The Securities of each series and the Trustee's certificates of
authentication thereof shall be in substantially the forms set forth in this
Article, or in such other forms as shall be established by or pursuant to a
Board Resolution or in one or more indentures supplemental hereto, in each case
with such appropriate legends, insertions, omissions, substitutions and other
variations as are required or permitted by this Indenture, and may have such
letters, numbers or other marks of identification and such legends or
endorsements placed thereon as


                                      -18-
<PAGE>   26

may be required to comply with the rules of any securities exchange or as may,
consistently herewith, be determined by the officers executing such Securities,
as evidenced by their execution of the Securities. If the form of Securities of
any series is established by action taken pursuant to a Board Resolution, a copy
of an appropriate record of such action shall be certified by the Secretary or
an Assistant Secretary of the Company and delivered to the Trustee at or prior
to the delivery of the Company Order contemplated by Section 303 for the
authentication and delivery of such Securities.

      The definitive Securities shall be printed, lithographed or engraved or
produced by any combination of these methods on steel engraved borders or may be
produced in any other manner, all as determined by the officers executing such
Securities, as evidenced by their execution of such Securities.

SECTION 202.   [intentionally omitted].

SECTION 203.   [intentionally omitted].

SECTION 204.   Additional Provisions Required in Global Security.

      Unless otherwise specified as contemplated by Section 301 for the
Securities evidenced thereby, every Global Security issued hereunder shall bear
a legend in substantially the following form:

      [If a Global Security, insert -- THIS SECURITY IS A GLOBAL SECURITY
WITHIN THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN
THE NAME OF A DEPOSITARY OR A NOMINEE THEREOF. THIS SECURITY MAY NOT BE
EXCHANGED IN WHOLE OR IN PART FOR A SECURITY REGISTERED, AND NO TRANSFER OF THIS
SECURITY IN WHOLE OR IN PART MAY BE REGISTERED, IN THE NAME OF ANY PERSON OTHER
THAN SUCH DEPOSITARY OR A NOMINEE THEREOF, EXCEPT IN THE LIMITED CIRCUMSTANCES
DESCRIBED IN THE INDENTURE.]

      [If a Global Security to be held by The Depository Trust Company, insert
-- UNLESS THIS SECURITY IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO ISSUER OR ITS AGENT
FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY SECURITY ISSUED IS
REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN
AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO
SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY
TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY A PERSON IS
WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST
HEREIN.]

SECTION 205.   Form of Trustee's Certificate of Authentication.

      The Trustee's certificate of authentication shall be in substantially the
following form:

This is one of the Securities of the series designated therein referred to in
the within-mentioned Indenture.

                                      -19-
<PAGE>   27


                                   ------------------------------,
                                   as Trustee


                                   By
                                      ------------------------------------------
                                      Authorized Signatory


                                 ARTICLE THREE

                                 THE SECURITIES

SECTION 301.   Amount Unlimited; Issuable in Series.

      The aggregate principal amount of Securities which may be authenticated
and delivered under this Indenture is unlimited.

      The Securities may be issued in one or more series. There shall be
established in or pursuant to a Board Resolution and, subject to Section 303,
set forth, or determined in the manner provided, in an Officers' Certificate, or
established in one or more indentures supplemental hereto, prior to the issuance
of Securities of any series,

             (1)    the title of the Securities of the series (which shall
      distinguish the Securities of the series from Securities of any other
      series);

             (2)    any limit upon the aggregate principal amount of the
      Securities of the series which may be authenticated and delivered under
      this Indenture (except for Securities authenticated and delivered upon
      registration of transfer of, or in exchange for, or in lieu of, other
      Securities of the series pursuant to Section 304, 305, 306, 906 or 1107
      and except for any Securities which, pursuant to Section 303, are deemed
      never to have been authenticated and delivered hereunder);

             (3)    the Person to whom any interest on a Security of the series
      shall be payable, if other than the Person in whose name that Security (or
      one or more Predecessor Securities) is registered at the close of business
      on the Regular Record Date for such interest;

             (4)    the date or dates on which the principal of any Securities
      of the series is payable;

             (5)    the rate or rates at which any Securities of the series
      shall bear interest, if any, the date or dates from which any such
      interest shall accrue, the Interest Payment Dates on which any such
      interest shall be payable and the Regular Record Date for any such
      interest payable on any Interest Payment Date;

                                      -20-
<PAGE>   28

              (6)   the place or places where the principal of and any premium
        and interest on any Securities of the series shall be payable;

              (7)   the period or periods within which, the price or prices at
        which and the terms and conditions upon which any Securities of the
        series may be redeemed, in whole or in part, at the option of the
        Company and, if other than by a Board Resolution, the manner in which
        any election by the Company to redeem the Securities shall be evidenced;

              (8)   the obligation, if any, of the Company to redeem or purchase
        any Securities of the series pursuant to any sinking fund or analogous
        provisions or at the option of the Holder thereof and the period or
        periods within which, the price or prices at which and the terms and
        conditions upon which any Securities of the series shall be redeemed or
        purchased, in whole or in part, pursuant to such obligation;

              (9)   if other than denominations of $1,000 and any integral
        multiple thereof, the denominations in which any Securities of the
        series shall be issuable;

             (10)   if the amount of principal of or any premium or interest on
        any Securities of the series may be determined with reference to an
        index or pursuant to a formula, the manner in which such amounts shall
        be determined;

             (11)   if other than the currency of the United States of America,
        the currency, currencies or currency units in which the principal of or
        any premium or interest on any Securities of the series shall be payable
        and the manner of determining the equivalent thereof in the currency of
        the United States of America for any purpose, including for purposes of
        the definition of "Outstanding" in Section 101;

             (12)   if the principal of or any premium or interest on any
        Securities of the series is to be payable, at the election of the
        Company or the Holder thereof, in one or more currencies or currency
        units other than that or those in which such Securities are stated to be
        payable, the currency, currencies or currency units in which the
        principal of or any premium or interest on such Securities as to which
        such election is made shall be payable, the periods within which and the
        terms and conditions upon which such election is to be made and the
        amount so payable (or the manner in which such amount shall be
        determined);

             (13)   if other than the entire principal amount thereof, the
        portion of the principal amount of any Securities of the series which
        shall be payable upon declaration of acceleration of the Maturity
        thereof pursuant to Section 502;

             (14)   if the principal amount payable at the Stated Maturity of
        any Securities of the series will not be determinable as of any one or
        more dates prior to the Stated Maturity, the amount which shall be
        deemed to be the principal amount of such Securities as of any such date
        for any purpose thereunder or hereunder, including the principal amount
        thereof which shall be due and payable upon any Maturity other than the
        Stated Maturity or which shall be deemed to be Outstanding as of any
        date prior to the Stated


                                      -21-
<PAGE>   29
      Maturity (or, in any such case, the manner in which such amount deemed to
      be the principal amount shall be determined);

             (15)   if applicable, that the Securities of the series, in whole
      or any specified part, shall be defeasible pursuant to Section 1202 or
      Section 1203 or both such Sections and, if other than by a Board
      Resolution, the manner in which any election by the Company to defease
      such Securities shall be evidenced;

             (16)   if applicable, that any Securities of the series shall be
      issuable in whole or in part in the form of one or more Global Securities
      and, in such case, the respective Depositaries for such Global Securities,
      the form of any legend or legends which shall be borne by any such Global
      Security in addition to or in lieu of that set forth in Section 204 and
      any circumstances in addition to or in lieu of those set forth in Clause
      (2) of the last paragraph of Section 305 in which any such Global Security
      may be exchanged in whole or in part for Securities registered, and any
      transfer of such Global Security in whole or in part may be registered, in
      the name or names of Persons other than the Depositary for such Global
      Security or a nominee thereof;

             (17)   any addition to or change in the Events of Default which
      applies to any Securities of the series and any change in the right of the
      Trustee or the requisite Holders of such Securities to declare the
      principal amount thereof due and payable pursuant to Section 502;

             (18)   any addition to or change in the covenants set forth in
      Article Ten which applies to Securities of the series;

             (19)   if the Securities of the series will be issued with original
      issue discount, the amount of original issue discount, the method by which
      the accreted value of the securities will be determined, the dates from
      and to which original issue discount will accrue and other provisions
      relating to original issue discount; and

             (20)   any other terms of the series (which terms shall not be
      inconsistent with the provisions of this Indenture, except as permitted by
      Section 901).

      All Securities of any one series shall be substantially identical except
as to denomination and except as may otherwise be provided in or pursuant to the
Board Resolution referred to above and (subject to Section 303) set forth, or
determined in the manner provided, in the Officers' Certificate referred to
above or in any such indenture supplemental hereto.

      If any of the terms of the series are established by action taken
pursuant to a Board Resolution, a copy of an appropriate record of such action
shall be certified by the Secretary or an Assistant Secretary of the Company and
delivered to the Trustee at or prior to the delivery of the Officers'
Certificate setting forth the terms of the series.

SECTION 302.   Denominations.

      The Securities of each series shall be issuable only in registered form
without coupons and only in such denominations as shall be specified as
contemplated by Section 301. In the

                                      -22-
<PAGE>   30

absence of any such specified denomination with respect to the Securities of any
series, the Securities of such series shall be issuable in denominations of
$1,000 and any integral multiple thereof.

SECTION 303.   Execution, Authentication, Delivery and Dating.

      The Securities shall be executed on behalf of the Company by its Chief
Executive Officer, its President, its Executive Vice President or one of its
Vice Presidents and attested by its Secretary or an Assistant Secretary. The
signature of any of these officers on the Securities may be manual or facsimile.

      Securities bearing the manual or facsimile signatures of individuals who
were at any time the proper officers of the Company shall bind the Company,
notwithstanding that such individuals or any of them have ceased to hold such
offices prior to the authentication and delivery of such Securities or did not
hold such offices at the date of such Securities.

      At any time and from time to time after the execution and delivery of
this Indenture, the Company may deliver Securities of any series executed by the
Company to the Trustee for authentication, together with a Company Order for the
authentication and delivery of such Securities; and the Trustee in accordance
with such Company Order shall authenticate and deliver such Securities.

      Each Security shall be dated the date of its authentication.

      No Security shall be entitled to any benefit under this Indenture or be
valid or obligatory for any purpose unless there appears on such Security a
certificate of authentication substantially in the form provided for herein
executed by the Trustee by manual signature, and such certificate upon any
Security shall be conclusive evidence, and the only evidence, that such Security
has been duly authenticated and delivered hereunder. Notwithstanding the
foregoing, if any Security shall have been authenticated and delivered hereunder
but never issued and sold by the Company, and the Company shall deliver such
Security to the Trustee for cancellation as provided in Section 309, for all
purposes of this Indenture such Security shall be deemed never to have been
authenticated and delivered hereunder and shall never be entitled to the
benefits of this Indenture.

SECTION 304.   Temporary Securities.

      Pending the preparation of definitive Securities of any series, the
Company may execute, and upon a Company Order the Trustee shall authenticate and
deliver, temporary Securities which are printed, lithographed, typewritten,
mimeographed or otherwise produced, in any authorized denomination,
substantially of the tenor of the definitive Securities in lieu of which they
are issued and with such appropriate insertions, omissions, substitutions and
other variations as the officers executing such Securities may determine, as
evidenced by their execution of such Securities.

      If temporary Securities of any series are issued, the Company will cause
definitive Securities of that series to be prepared without unreasonable delay.
After the preparation of definitive Securities of such series, the temporary
Securities of such series shall be exchangeable

                                      -23-
<PAGE>   31

for definitive Securities of such series upon surrender of the temporary
Securities of such series at any office or agency of the Company designated
pursuant to Section 1002, without charge to the Holder. Upon surrender for
cancellation of any one or more temporary Securities of any series, the Company
shall execute and the Trustee shall authenticate and deliver in exchange
therefor one or more definitive Securities of the same series, of any authorized
denominations and of like tenor and aggregate principal amount. Until so
exchanged, the temporary Securities of such series shall in all respects be
entitled to the same benefits under this Indenture as definitive Securities of
such series and tenor.

SECTION 305.   Registration, Registration of Transfer and Exchange.

      The Company shall cause to be kept at the Corporate Trust Office of the
Trustee a register (the register maintained in such office and in any other
office or agency designated pursuant to Section 1002 being herein sometimes
collectively referred to as the "Security Register") in which, subject to such
reasonable regulations as they may prescribe, the Company shall provide for the
registration of Securities and of transfers and exchanges of Securities. The
Trustee is hereby appointed "Security Registrar" for the purpose of registering
Securities and transfers and exchanges of Securities as herein provided.

      Upon surrender for registration of transfer of any Security of a series
at an office or agency of the Company designated pursuant to Section 1002 for
such purpose, the Company shall execute, and the Trustee shall authenticate and
deliver, in the name of the designated transferee or transferees, one or more
new Securities of the same series, of any authorized denominations and of a like
tenor and aggregate principal amount and bearing any applicable legends provided
as contemplated by this Indenture.

      At the option of the Holder, Securities of any series may be exchanged
for other Securities of the same series, of any authorized denominations and of
a like tenor and aggregate principal amount, upon surrender of the Securities to
be exchanged at such office or agency. Whenever any Securities are so
surrendered for exchange, the Company shall execute, and the Trustee shall
authenticate and deliver, the Securities which the Holder making the exchange is
entitled to receive.

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

      Every Security presented or surrendered for registration of transfer or
for exchange shall (if so required by the Company or the Trustee) be duly
endorsed, or be accompanied by a written instrument of transfer in form
satisfactory to the Company and the Security Registrar duly executed, by the
Holder thereof or his attorney duly authorized in writing.

      No service charge shall be made to the Holder for any registration of
transfer or exchange of Securities, but the Company may require payment of a sum
sufficient to cover any tax or other governmental charge that may be imposed in
connection with any registration of transfer or exchange of Securities, other
than exchanges pursuant to Section 304, 305, 906 or 1107 or in accordance with
any Offer to Purchase not involving any transfer.

                                      -24-
<PAGE>   32

      If the Securities of any series (or of any series and specified tenor) are
to be redeemed in part, the Company shall not be required (i) to issue, register
the transfer of or exchange any Securities of that series (or of that series and
specified tenor, as the case may be) during a period beginning at the opening of
business 15 days before the day of the mailing of a notice of redemption of
Securities selected for redemption under Section 1103 and ending at the close of
business on the day of such mailing, or (ii) to register the transfer of or
exchange any Security so selected for redemption in whole or in part, except the
unredeemed portion of any Security being redeemed in part.

      The provisions of Clauses (1), (2), (3) and (4) below shall apply only
to Global Securities:

             (1)    Each Global Security authenticated under this Indenture

      shall be registered in the name of the Depositary designated for such
      Global Security or a nominee thereof and delivered to such Depositary or a
      nominee thereof or custodian therefor, and each such Global Security shall
      constitute a single Security for all purposes of this Indenture.

             (2)    Notwithstanding any other provisions in this Indenture, no
      Global Security may be exchanged in whole or in part for Securities
      registered, and no transfer of a Global Security in whole or in part may
      be registered, in the name of any Person other than the Depositary for
      such Global Security or a nominee thereof unless (A) such Depositary (i)
      has notified the Company that it is unwilling or unable to continue as
      Depositary for such Global Security or (ii) has ceased to be a clearing
      agency registered under the Exchange Act, (B) there shall have occurred
      and be continuing an Event of Default with respect to such Global
      Security, or (C) there shall exist such circumstances, if any, in addition
      to or in lieu of the foregoing as have been specified for this purpose as
      contemplated by Section 301.

             (3)    Subject to Clause (2) above, any exchange of a Global
      Security for other Securities may be made in whole or in part, and all
      Securities issued in exchange for a Global Security or any portion thereof
      shall be registered in such names as the Depositary for such Global
      Security shall direct.

             (4)    Every Security authenticated and delivered upon registration
      of transfer of, or in exchange for or in lieu of, a Global Security or any
      portion thereof, whether pursuant to this Section, Section 304, 306, 906
      or 1107 or otherwise, shall be authenticated and delivered in the form of,
      and shall be, a Global Security, unless such Security is registered in the
      name of a Person other than the Depositary for such Global Security or a
      nominee thereof.

SECTION 306.   Mutilated, Destroyed, Lost and Stolen Securities.

      If any mutilated Security is surrendered to the Trustee, the Company
shall execute and the Trustee shall authenticate and deliver in exchange
therefor a new Security of the same series and of like tenor and principal
amount and bearing a number not contemporaneously outstanding.

      If there shall be delivered to the Company and the Trustee (i) evidence
to their satisfaction of the destruction, loss or theft of any Security and (ii)
such security or indemnity as may be required by them to save each of them and
any agent of either of them harmless, then, in the absence of notice to the
Company or the Trustee that such Security has been acquired by a bona fide
purchaser, the Company shall execute and the Trustee shall authenticate and
deliver, in

                                      -25-
<PAGE>   33

lieu of any such destroyed, lost or stolen Security, a new Security of the same
series and of like tenor and principal amount and bearing a number not
contemporaneously outstanding.

      In case any such mutilated, destroyed, lost or stolen Security has
become or is about to become due and payable, the Company in the discretion of
the Company may, instead of issuing a new Security, pay such Security.

      Upon the issuance of any new Security under this Section, the Company
may require the payment of a sum sufficient to cover any tax or other
governmental charge that may be imposed in relation thereto and any other
expenses (including the fees and expenses of the Trustee) connected therewith.

      Every new Security of any series issued pursuant to this Section in lieu
of any destroyed, lost or stolen Security shall constitute an original
additional contractual obligation of the Company, whether or not the destroyed,
lost or stolen Security shall be at any time enforceable by anyone, and shall be
entitled to all the benefits of this Indenture equally and proportionately with
any and all other Securities of that series duly issued hereunder.

      The provisions of this Section are exclusive and shall preclude (to the
extent lawful) all other rights and remedies with respect to the replacement or
payment of mutilated, destroyed, lost or stolen Securities.

SECTION 307.   Payment of Interest; Interest Rights Preserved.

      Except as otherwise provided as contemplated by Section 301 with respect
to any series of Securities, interest on any Security which is payable, and is
punctually paid or duly provided for, on any Interest Payment Date shall be paid
to the Person in whose name that Security (or one or more Predecessor
Securities) is registered at the close of business on the Regular Record Date
for such interest.

      Any interest on any Security of any series which is payable, but is not
punctually paid or duly provided for, on any Interest Payment Date (herein
called "Defaulted Interest") shall (a) bear interest at the rate stated in the
form of Security provided as contemplated by Section 301 with respect to any
series of Securities (to the extent that the payment of such interest shall be
legally enforceable), and (b) forthwith cease to be payable to the Holder on the
relevant Regular Record Date by virtue of having been such Holder, and such
Defaulted Interest may be paid by the Company, at its election in each case, as
provided in Clause (1) or (2) below:

             (1)    The Company may elect to make payment of any Defaulted
      Interest to the Persons in whose names the Securities of such series (or
      their respective Predecessor Securities) are registered at the close of
      business on a Special Record Date for the payment of such Defaulted
      Interest, which shall be fixed in the following manner. The Company shall
      notify the Trustee in writing of the amount of Defaulted Interest proposed
      to be paid on each Security of such series and the date of the proposed
      payment, and at the same time the Company shall deposit with the Trustee
      an amount of money equal to the aggregate amount proposed to be paid in
      respect of such Defaulted Interest or shall make arrangements satisfactory
      to the Trustee for such deposit prior to the date of the proposed payment,
      such money when deposited to be held in trust for the benefit of the


                                      -26-
<PAGE>   34
      Persons entitled to such Defaulted Interest as in this Clause provided.
      Thereupon the Trustee shall fix a Special Record Date for the payment of
      such Defaulted Interest which shall be not more than 15 days and not less
      than 10 days prior to the date of the proposed payment and not less than
      10 days after the receipt by the Trustee of the notice of the proposed
      payment. The Trustee shall promptly notify the Company of such Special
      Record Date and, in the name and at the expense of the Company, shall
      cause notice of the proposed payment of such Defaulted Interest and the
      Special Record Date therefor to be mailed, first-class postage prepaid, to
      each Holder of Securities of such series at his address as it appears in
      the Security Register, not less than 10 days prior to such Special Record
      Date. Notice of the proposed payment of such Defaulted Interest and the
      Special Record Date therefor having been so mailed, such Defaulted
      Interest shall be paid to the Persons in whose names the Securities of
      such series (or their respective Predecessor Securities) are registered at
      the close of business on such Special Record Date and shall no longer be
      payable pursuant to the following Clause (2).

             (2)    The Company may make payment of any Defaulted Interest on
      the Securities of any series in any other lawful manner not inconsistent
      with the requirements of any securities exchange on which such Securities
      may be listed, and upon such notice as may be required by such exchange,
      if, after notice given by the Company to the Trustee of the proposed
      payment pursuant to this Clause, such manner of payment shall be deemed
      practicable by the Trustee.

      Subject to the foregoing provisions of this Section, each Security
delivered under this Indenture upon registration of transfer of or in exchange
for or in lieu of any other Security shall carry the rights to interest accrued
and unpaid, and to accrue, which were carried by such other Security.

SECTION 308.   Persons Deemed Owners.

      Prior to due presentment of a Security for registration of transfer, the
Company, the Trustee and any agent of the Company or the Trustee may treat the
Person in whose name such Security is registered as the owner of such Security
for the purpose of receiving payment of principal of and premium, if any, and
(subject to Section 307) interest on such Security and for all other purposes
whatsoever, whether or not such Security be overdue, and none of the Company,
the Trustee or any agent of the Company or the Trustee shall be affected by
notice to the contrary.

SECTION 309.   Cancellation.

     All Securities surrendered for payment, redemption, registration of
transfer, exchange, for credit against any sinking fund payment or pursuant to
any Offer to Purchase shall, if surrendered to any Person other than the
Trustee, be delivered to the Trustee and shall be promptly cancelled by it. The
Company may at any time deliver to the Trustee for cancellation any Securities
previously authenticated and delivered hereunder which the Company may have
acquired in any manner whatsoever, and all Securities so delivered shall be
promptly cancelled by the Trustee. No Securities shall be authenticated in lieu
of or in exchange for any Securities cancelled as provided in this Section,
except as expressly permitted by this Indenture. All


                                      -27-
<PAGE>   35

cancelled Securities held by the Trustee shall be disposed of in accordance with
its standard procedures or as directed by a Company Order.

SECTION 310.   Computation of Interest.

      Except as otherwise specified as contemplated by Section 301 for
Securities of any series, interest on the Securities of each series shall be
computed on the basis of a 360-day year of twelve 30-day months.

SECTION 311.   CUSIP Numbers.

      The Company shall in issuing the Securities of any series use CUSIP
numbers, and the Trustee shall use the applicable CUSIP number in notices of
redemption or exchange as a convenience to the Holders of the Securities of the
relevant series; provided, that any such notice may state that no representation
is made as to the accuracy or correctness of the CUSIP number or numbers printed
in the notice or on the certificates representing the Securities of the relevant
series and that reliance may be placed only on the other identification numbers
printed on the certificates representing the Securities of such series.

                                  ARTICLE FOUR

                           SATISFACTION AND DISCHARGE

SECTION 401. Satisfaction and Discharge of Indenture.

      This Indenture shall cease to be of further effect as to all Outstanding
Securities (except as to (i) rights of registration of transfer and exchange and
the Company's right of optional redemption, (ii) substitution of apparently
mutilated, defaced, destroyed, lost or stolen Securities, (iii) rights of
holders of Securities to receive payment of principal of and premium, if any,
and interest on the Securities, (iv) rights, obligations and immunities of the
Trustee under the Indenture and (v) rights of the holders of the Securities as
beneficiaries of the Indenture with respect to any property deposited with the
Trustee payable to all or any of them), and the Trustee, on demand of and at the
expense of the Company, shall execute proper instruments acknowledging
satisfaction and discharge of this Indenture, when

            (1)     either

                    (A)    the Company will have paid or caused to be paid the
            principal of, premium, if any, and interest on the Securities as
            and when the same will have become due and payable; or

                    (B)    all Outstanding Securities (except lost, stolen or
            destroyed Securities which have been replaced or paid) have been
            delivered to the Trustee for cancellation;

      and the Company, in the case of (A) above, has deposited or caused to be
      deposited with the Trustee as trust funds in trust for the purpose an
      amount sufficient to pay and



                                      -28-
<PAGE>   36
      discharge the entire indebtedness on such Securities not theretofore
      delivered to the Trustee for cancellation, for principal of and premium,
      if any, and interest to the date of such deposit (in the case of
      Securities which have become due and payable) or to the Stated Maturity or
      Redemption Date, as the case may be;

             (2)    the Company has paid or caused to be paid all other sums
      payable hereunder by the Company;

             (3)    the Company has delivered to the Trustee an Officers'
      Certificate and an Opinion of Counsel, each stating that all conditions
      precedent herein provided for relating to the satisfaction and discharge
      of this Indenture have been complied with; and

             (4)    the Trustee shall have received such other documents and
      assurances as the Trustee shall have reasonably requested.

Notwithstanding the satisfaction and discharge of this Indenture, (i) the
obligations of the Company to the Trustee under Section 607, (ii) substitution
of apparently mutilated, defaced, destroyed, lost or stolen Securities of any
series, (iii) rights of Holders of Securities of any series to receive payment
of principal of and premium, if any, and interest on the Securities of such
series, (iv) rights, obligations and immunities of the Trustee under this
Indenture (including, if money shall have been deposited with the Trustee
pursuant to subclause (B) of Clause (1) of this Section, the obligations of the
Trustee under Section 402 and the last paragraph of Section 1003), and (v)
rights of Holders of the Securities of any series as beneficiaries of this
Indenture with respect to any property deposited with the Trustee payable to all
or any of them, shall survive.

SECTION 402.   Application of Trust Money.

      Subject to the provisions of the last paragraph of Section 1003, all
money deposited with the Trustee pursuant to Section 401 shall be held in trust
and applied by it, in accordance with the provisions of the Securities and this
Indenture, to the payment, either directly or through any Paying Agent
(including the Company acting as its own Paying Agent) as the Trustee may
determine, to the Persons entitled thereto, of the principal (and premium, if
any) and interest for whose payment such money has been deposited with the
Trustee.

                                  ARTICLE FIVE

                                    REMEDIES

SECTION 501.   Events of Default.

      "Event of Default", wherever used herein with respect to Securities of
any series, means any one of the following events (whatever the reason for such
Event of Default and whether it shall be voluntary or involuntary or be effected
by operation of law or pursuant to any judgment, decree or order of any court or
any order, rule or regulation of any administrative or governmental body):

                                      -29-
<PAGE>   37

            (1)     default in the payment of any interest upon any Security of
        that series when it becomes due and payable, and continuance of such
        default for a period of 30 days; or

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

            (3)     default in the payment of principal and interest upon any
        Security of that series required to be purchased pursuant to an Offer to
        Purchase when due and payable; or

            (4)     if applicable, default in the deposit of any sinking fund
        payment when and as due by the terms of a Security of that series; or

            (5)     default in the performance, or breach, of Section 801 by the
        Company; or

            (6)     default in the performance, or breach, of any covenant or
        warranty of the Company in this Indenture or in any Security (other than
        a covenant or warranty a default in whose performance or whose breach is
        elsewhere in this Section specifically dealt with or which has expressly
        been included in this Indenture solely for the benefit of series of
        Securities other than that series), and continuance of such default or
        breach for a period of 60 days after there has been given, by registered
        or certified mail, to the Company by the Trustee or to the Company and
        the Trustee by the Holders of at least 25% in aggregate principal amount
        of the Outstanding Securities of that series a written notice specifying
        such default or breach and requiring it to be remedied and stating that
        such notice is a "Notice of Default" hereunder; or

            (7)     a default or defaults under any bond(s), debenture(s),
        note(s) or other evidence(s) of Debt by the Company or any Significant
        Subsidiary of the Company or under any mortgage(s), indenture(s) or
        instrument(s) under which there may be issued or by which there may be
        secured or evidenced any Debt of such type by the Company or any such
        Significant Subsidiary with a principal amount then outstanding,
        individually or in the aggregate, in excess of an amount specified as
        contemplated by Section 301 for Securities of that series, whether such
        Debt now exists or shall hereafter be created, which default or defaults
        shall constitute a failure to pay such Debt when due at the final
        maturity thereof, or shall have resulted in such Debt becoming or being
        declared due and payable prior to the date on which it would otherwise
        have become due and payable; or

            (8)     a final judgment or final judgments (not subject to appeal)
        for the payment of money are entered against the Company or any
        Significant Subsidiary in an aggregate amount in excess of an amount
        specified as contemplated by Section 301 for Securities of that series
        by a court or courts of competent jurisdiction, which judgments remain
        undischarged or unstayed for a period (during which execution shall not
        be effectively stayed) of 45 days after the right to appeal all such
        judgments has expired; or

            (9)     the entry by a court having jurisdiction in the premises of
        (A) a decree or order for relief in respect of the Company or any
        Significant Subsidiary in an involuntary case or proceeding under any
        applicable Federal or State bankruptcy, insolvency,


                                      -30-
<PAGE>   38
      reorganization or other similar law or (B) a decree or order adjudging the
      Company or any Significant Subsidiary a bankrupt or insolvent, or
      approving as properly filed a petition seeking reorganization,
      arrangement, adjustment or composition of or in respect of the Company or
      any Significant Subsidiary under any applicable Federal or State law, or
      appointing a custodian, receiver, liquidator, assignee, trustee,
      sequestrator or other similar official of the Company or any Significant
      Subsidiary or of any substantial part of its property, or ordering the
      winding up or liquidation of its affairs, and the continuance of any such
      decree or order for relief or any such other decree or order unstayed and
      in effect for a period of 60 consecutive days;

             (10)   the commencement by the Company or any Significant
      Subsidiary of a voluntary case or proceeding under any applicable Federal
      or State bankruptcy, insolvency, reorganization or other similar law or of
      any other case or proceeding to be adjudicated a bankrupt or insolvent, or
      the consent by it to the entry of a decree or order for relief in respect
      of the Company or any Significant Subsidiary in an involuntary case or
      proceeding under any applicable Federal or State bankruptcy, insolvency,
      reorganization or other similar law or to the commencement of any
      bankruptcy or insolvency case or proceeding against it, or the filing by
      it of a petition or answer or consent seeking reorganization or relief
      under any applicable Federal or State law, or the consent by it to the
      filing of such petition or to the appointment of or taking possession by a
      custodian, receiver, liquidator, assignee, trustee, sequestrator or other
      similar official of the Company or any Significant Subsidiary or of any
      substantial part of its property, or the making by it of an assignment for
      the benefit of creditors, or the admission by it in writing of its
      inability to pay its debts generally as they become due, or the taking of
      corporate action by the Company or any Significant Subsidiary in
      furtherance of any such action; or

      (ii) any other Event of Default provided as contemplated by Section 301
with respect to Securities of that series.

SECTION 502.   Acceleration of Maturity; Rescission and Annulment.

      If an Event of Default (other than an Event of Default specified in
Section 501(9) or (10) with respect to the Company) with respect to Securities
of any series at the time Outstanding occurs and is continuing, then and in
every such case the Trustee or the Holders of not less than 25% in aggregate
principal amount of the Outstanding Securities of that series may declare the
Default Amount of all the Securities of that series to be due and payable
immediately, by a notice in writing to the Company (and to the Trustee if given
by Holders), and upon any such declaration such Default Amount and any accrued
interest, together with all other amounts due under this Indenture with respect
to such series of Outstanding Securities, shall become immediately due and
payable. If an Event of Default specified in Section 501(9) or (10) with respect
Securities of any series at the time Outstanding occurs, the Default Amount of
and any accrued interest on the Securities of such series then Outstanding,
together with all other amounts due under this Indenture, shall ipso facto
become immediately due and payable without any declaration or other Act on the
part of the Trustee or any Holder.

      The "Default Amount" in respect of any Security of a particular series
as of any particular date of acceleration shall equal the principal amount of
the Security plus accrued and unpaid interest to such date.

                                      -31-
<PAGE>   39

      At any time after such a declaration of acceleration with respect to
Securities of any series has been made and before a judgment or decree for
payment of the money due based on acceleration has been obtained by the Trustee
as hereinafter in this Article provided, the Holders of a majority in aggregate
principal amount of the Outstanding Securities of that series, by written notice
to the Company and the Trustee, may rescind and annul such declaration and its
consequences if:

             (1)    the Company has paid or deposited with the Trustee a sum
      sufficient to pay

                    (A)    all overdue interest on all Securities of that
             series,

                    (B)    the principal of (and premium, if any, on) any
             Securities of that series which have become due otherwise than by
             such declaration of acceleration (including any Securities of that
             series required to have been purchased on the Purchase Date
             pursuant to an Offer to Purchase made by the Company) and interest
             thereon at the rate borne by such series of Securities,

                    (C)    to the extent that payment of such interest is
             lawful, interest upon overdue interest at the applicable rate borne
             by the Securities of that series, and

                    (D)    all sums paid or advanced by the Trustee hereunder
             and the reasonable compensation, expenses, disbursements and
             advances of the Trustee, its agents and counsel;

      and

             (2)    all Events of Default with respect to Securities of that
      series, other than the non-payment of the principal of Securities of that
      series which have become due solely by such declaration of acceleration,
      have been cured or waived as provided in Section 513.

No such rescission shall affect any subsequent default or impair any right
consequent thereon.

SECTION 503.   Collection of Indebtedness and Suits for Enforcement by Trustee.

      The Company covenants that if

             (1)    default is made in the payment of any interest on any
      Security of any series when such interest becomes due and payable and such
      default continues for a period of 30 days, or

             (2)    default is made in the payment of the principal of (or
      premium, if any, on) any Security of any series at the Maturity thereof
      or, with respect to any Security required to have been purchased pursuant
      to an Offer to Purchase made by the Company, at the Purchase Date thereof,

                                      -32-
<PAGE>   40

the Company will, upon demand of the Trustee, pay to it, for the benefit of the
Holders of such Securities of such series, the whole amount then due and payable
on such Securities for principal (and premium, if any) and interest, and, to the
extent that payment of such interest shall be legally enforceable, interest on
any overdue principal (and premium, if any) and on any overdue interest, at the
rate or rates prescribed therefor in such Securities and, in addition thereto,
such further amount as shall be sufficient to cover the costs and expenses of
collection incurred by the Trustee under this Indenture, including the
reasonable compensation, expenses, disbursements and advances of the Trustee,
its agents and counsel.

      If the Company fails to pay such amounts forthwith upon such demand, the
Trustee, in its own name and as trustee of an express trust, may institute a
judicial proceeding for the collection of the sums so due and unpaid, may
prosecute such proceeding to judgment or final decree, and may enforce the same
against the Company or any other obligor upon the Securities of the relevant
series and collect the moneys adjudged or decreed to be payable in the manner
provided by law out of the property of the Company or any other obligor upon
such Securities, wherever situated.

      If an Event of Default occurs and is continuing with respect to
Securities of any series, the Trustee may in its discretion proceed to protect
and enforce its rights and the rights of the Holders of Securities of such
series by such appropriate judicial proceedings as the Trustee shall deem most
effective to protect and enforce any such rights, whether for the specific
enforcement of any covenant or agreement in this Indenture or in aid of the
exercise of any power granted herein, or to enforce any other proper remedy.

SECTION 504.   Trustee May File Proofs of Claim.

      In case of any judicial proceeding relative to the Company (or any other
obligor upon the Securities), its property or its creditors, the Trustee shall
be entitled and empowered, by intervention in such proceeding or otherwise, to
take any and all actions authorized under the Trust Indenture Act in order to
have claims of the Holders and the Trustee allowed in any such proceeding. In
particular, the Trustee shall be authorized to collect and receive any moneys,
securities or other property payable or deliverable upon the exchange of the
Securities or upon any such claims and to distribute the same; and any
custodian, receiver, assignee, trustee, liquidator, sequestrator or other
similar official 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 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 607.

      No provision of this Indenture 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
Securities or the rights of any Holder thereof or to authorize the Trustee to
vote in respect of the claim of any Holder in any such proceeding; provided,
however, that the Trustee may, on behalf of the Holders, vote for the election
of a trustee in bankruptcy or similar official and be a member of a creditors or
other similar committee.

                                      -33-
<PAGE>   41

SECTION 505.   Trustee May Enforce Claims Without Possession of Securities.

      All rights of action and claims under this Indenture or the Securities
may be prosecuted and enforced by the Trustee without the possession of any of
the Securities or the production thereof in any proceeding relating thereto, and
any such proceeding instituted by the Trustee shall be brought in its own name
as trustee of an express trust, and any recovery of judgment shall, after
provision for the payment of the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel, be for the
ratable benefit of the Holders of the Securities in respect of which such
judgment has been recovered.

SECTION 506.   Application of Money Collected.

      Any money collected by the Trustee pursuant to this Article shall be
applied in the following order, at the date or dates fixed by the Trustee and,
in case of the distribution of such money on account of principal (or premium,
if any) or interest, upon presentation of the Securities and the notation
thereon of the payment if only partially paid and upon surrender thereof if
fully paid:

            FIRST:  To the payment of all amounts due the Trustee under Section
607; and

            SECOND: To the payment of the amounts then due and unpaid for
principal of (and premium, if any) and interest on the Securities in respect of
which or for the benefit of which such money has been collected, ratably,
without preference or priority of any kind, according to the amounts due and
payable on such Securities for principal (and premium, if any) and interest,
respectively.

      The Trustee, upon prior written notice to the Company, may fix a record
date and payment date for any payment to the Holders of Securities of any series
pursuant to this Section 506.

SECTION 507.   Limitation on Suits.

      No Holder of any Security of any series shall have any right to
institute any proceeding, judicial or otherwise, with respect to this Indenture,
or for the appointment of a receiver or trustee, or for any other remedy
hereunder, unless

             (1)    such Holder has previously given written notice to the
      Trustee of a continuing Event of Default with respect to the Securities of
      that series;

             (2)    the Holders of at least 25% in aggregate principal amount of
      the Outstanding Securities of that series shall have made written request
      to the Trustee to institute proceedings in respect of such Event of
      Default in its own name as Trustee hereunder;

             (3)    such Holder or Holders have offered and, if requested,
      provided to the Trustee reasonable indemnity against the costs, expenses
      and liabilities to be incurred in compliance with such request;



                                      -34-
<PAGE>   42

             (4)    the Trustee for 60 days after its receipt of such notice,
      request and offer and, if requested, provision of indemnity has failed to
      institute any such proceeding; and

             (5)     no direction inconsistent with such written request has
      been given to the Trustee during such 60-day period by the Holders of a
      majority in principal amount of the Outstanding Securities of that series;

it being understood and intended that no one or more of such Holders shall have
any right in any manner whatever by virtue of, or by availing of, any provision
of this Indenture to affect, disturb or prejudice the rights of any other of
such Holders, or to obtain or to seek to obtain priority or preference over any
other of such Holders or to enforce any right under this Indenture, except in
the manner herein provided and for the equal and ratable benefit of all of such
Holders.

SECTION 508.   Unconditional Right of Holders to Receive Principal, Premium and
               Interest.


      Notwithstanding any other provision in this Indenture, the Holder of any
Security shall have the right, which is absolute and unconditional, to receive
payment of the principal of (and premium, if any) and (subject to Section 307)
interest on such Security on the respective Stated Maturities expressed in such
Security (or, in the case of redemption, on the Redemption Date or, in the case
of an Offer to Purchase made by the Company and required to be accepted as to
such Security, on the Purchase Date) and to institute suit for the enforcement
of any such payment, and such rights shall not be impaired without the consent
of such Holder.

SECTION 509.   Restoration of Rights and Remedies.

      If the Trustee or any Holder has instituted any proceeding to enforce
any right or remedy under this Indenture and such proceeding has been
discontinued or abandoned for any reason, or has been determined adversely to
the Trustee or to such Holder, then and in every such case, subject to any
determination in such proceeding, the Company, the Trustee and the Holders shall
be restored severally and respectively to their former positions hereunder and
thereafter all rights and remedies of the Trustee and the Holders shall continue
as though no such proceeding had been instituted.

SECTION 510.   Rights and Remedies Cumulative.

      Except as otherwise provided with respect to the replacement or payment of
mutilated, destroyed, lost or stolen Securities in the last paragraph of Section
306, no right or remedy herein conferred upon or reserved to the Trustee or to
the Holders is intended to be exclusive of any other right or remedy, and every
right and remedy shall, to the extent permitted by law, be cumulative and in
addition to every other right and remedy given hereunder or now or hereafter
existing at law or in equity or otherwise. The assertion or employment of any
right or remedy hereunder, or otherwise, shall not prevent the concurrent
assertion or employment of any other appropriate right or remedy.



                                      -35-
<PAGE>   43
SECTION 511.   Delay or Omission Not Waiver.

        No delay or omission of the Trustee or of any Holder of any Securities
to exercise any right or remedy accruing upon any Event of Default shall impair
any such right or remedy or constitute a waiver of any such Event of Default or
an acquiescence therein. Every right and remedy given by this Article or by law
to the Trustee or to the Holders may be exercised from time to time, and as
often as may be deemed expedient, by the Trustee or by the Holders, as the case
may be.

SECTION 512.   Control by Holders.

        By giving the Required Consent, those Persons giving the Required
Consent shall have the right to direct the time, method and place of conducting
any proceeding for any remedy available to the Trustee or exercising any trust
or power conferred on the Trustee, with respect to Securities of the relevant
series, provided that:

                (1) such direction shall not be in conflict with any rule of law
        or with this Indenture or expose the Trustee to personal liability (as
        determined in the sole discretion of the Trustee), and

                (2) the Trustee may take any other action deemed proper by the
        Trustee which is not inconsistent with such direction.

SECTION 513.   Waiver of Past Defaults.

        By giving the Required Consent, those Persons giving the Required
Consent may, on behalf of the Holders of all Securities of the relevant series,
waive any past default hereunder with respect to such series and its
consequences, except a default:

                (1) in the payment of the principal of (or premium, if any) or
        interest on any Security of such series (including any Security of such
        series which is required to have been purchased pursuant to an Offer to
        Purchase which has been made by the Company), or

                (2) in respect of a covenant or provision hereof which under
        Article Nine cannot be modified or amended without the consent of the
        Holder of each Outstanding Security of such series affected, or

                (3) arising from failure to purchase any Security of such series
        tendered pursuant to an Offer to Purchase.

        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.






                                      -36-
<PAGE>   44

SECTION 514.   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 Trustee, a court may require any party litigant in such suit to file an
undertaking to pay the costs of such suit, and may assess costs against any such
party litigant, in the manner and to the extent provided in the Trust Indenture
Act; provided that neither this Section nor the Trust Indenture Act shall be
deemed to authorize any court to require such an undertaking or to make such an
assessment in any suit instituted by the Company.

SECTION 515.   Waiver of Stay or Extension Laws.

        The Company covenants (to the extent that it may lawfully do so) that it
will not at any time insist upon, or plead, or in any manner whatsoever claim or
take the benefit or advantage of, any stay or extension law wherever enacted,
now or at any time hereafter in force, which 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 will not hinder, delay or impede the execution of any
power herein granted to the Trustee, but will suffer and permit the execution of
every such power as though no such law had been enacted.

                                  ARTICLE SIX

                                  THE TRUSTEE

SECTION 601.   Certain Duties and Responsibilities.

        The duties and responsibilities of the Trustee shall be as provided by
the Trust Indenture Act. Notwithstanding the foregoing, no provision of this
Indenture shall require the Trustee to expend or risk its own funds or otherwise
incur any financial liability in the performance of any of its duties hereunder,
or in the exercise of any of its rights or powers, if it shall have reasonable
grounds for believing that repayment of such funds or adequate indemnity against
such risk or liability is not reasonably assured to it. Whether or not therein
expressly so provided, every provision of this Indenture relating to the conduct
or affecting the liability of or affording protection to the Trustee shall be
subject to the provisions of this Section.

SECTION 602.   Notice of Defaults.

        If a Default occurs hereunder with respect to Securities of any series,
the Trustee shall give the Holders of Securities of such series notice of such
Default as and to the extent provided by the Trust Indenture Act, unless such
Default has been cured or waived; provided, however, that in the case of any
Default of the character specified in Section 501(6) with respect to Securities
of such series, no such notice to Holders of Securities of such series shall be
given until at least 30 days after the occurrence thereof.

SECTION 603.   Certain Rights of Trustee.

        Subject to the provisions of Section 601:





                                      -37-
<PAGE>   45

        (a) the Trustee may rely and shall be protected in acting or refraining
from acting upon any resolution, certificate, statement, instrument, opinion,
report, notice, request, direction, consent, order, bond, debenture, note, other
evidence of indebtedness or other paper or document believed by it to be genuine
and to have been signed or presented by the proper party or parties;

        (b) any request or direction of the Company mentioned herein shall be
sufficiently evidenced by a Company Request or a Company Order and any
resolution of the Board of Directors may be sufficiently evidenced by a Board
Resolution;

        (c) whenever in the administration of this Indenture the Trustee shall
deem it desirable that a matter be proved or established prior to taking,
suffering or omitting any action hereunder, the Trustee (unless other evidence
be herein specifically prescribed) may, in the absence of bad faith on its part,
rely upon an Officers' Certificate or an Opinion of Counsel;

        (d) the Trustee may consult with counsel and the written advice of such
counsel or any Opinion of Counsel shall be full and complete authorization and
protection in respect of any action taken, suffered or omitted by it hereunder
in good faith and in reliance thereon;

        (e) 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 of Securities of any series pursuant to this Indenture,
unless such Holders shall have offered to the Trustee reasonable security or
indemnity against the costs, expenses and liabilities which might be incurred by
it in compliance with such request or direction reasonably satisfactory to the
Trustee;

        (f) the Trustee shall not be bound to make any investigation into the
facts or matters stated in any resolution, certificate, statement, instrument,
opinion, report, notice, request, direction, consent, order, bond, debenture,
note, other evidence of indebtedness or other paper or document, but the
Trustee, in its discretion, may make such further inquiry or investigation into
such facts or matters as it may see fit, and, if the Trustee shall determine to
make such further inquiry or investigation, it shall be entitled to examine the
books, records and premises of the Company, personally or by agent or attorney;

        (g) the Trustee may execute any of the trusts or powers hereunder or
perform any duties hereunder either directly or by or through agents or
attorneys and the Trustee shall not be responsible for any misconduct or
negligence on the part of any agent or attorney appointed with due care by it
hereunder; and

        (h) the Trustee shall not be liable for any action taken, suffered or
omitted by it in good faith which the Trustee reasonably believed to have been
authorized or within its rights or powers.

SECTION 604.   Not Responsible for Recitals or Issuance of Securities.

        The recitals contained herein and in the Securities of any series,
except the Trustee's certificates of authentication, shall be taken as the
statements of the Company, and the Trustee assumes no responsibility for their
correctness. The Trustee and any Authenticating Agent make no representations
as to the validity or sufficiency of this Indenture or the Securities of any
series. The Trustee and any Authenticating Agent shall not be






                                      -38-
<PAGE>   46

accountable for the use or application by the Company of Securities of
any series or the proceeds thereof.

SECTION 605.   May Hold Securities.

        The Trustee, any Authenticating Agent, any Paying Agent, any Security
Registrar (if other than the Trustee) or any other agent of the Company, in its
individual or any other capacity, may become the owner or pledgee of Securities
of any series and, subject to Sections 608 and 613, may otherwise deal with the
Company with the same rights it would have if it were not Trustee,
Authenticating Agent, Paying Agent, Security Registrar or such other agent.

SECTION 606.   Money Held in Trust.

        Money held by the Trustee in trust hereunder need not be segregated from
other funds except to the extent required by law. The Trustee shall be under no
liability for interest on any money received by it hereunder except as otherwise
agreed with the Company.

SECTION 607.   Compensation and Reimbursement.

        The Company agrees:

                (1) to pay to the Trustee from time to time reasonable
        compensation for all services rendered by it hereunder (which
        compensation shall not be limited by any provision of law in regard to
        the compensation of a trustee of an express trust);

                (2) except as otherwise expressly provided herein, to reimburse
        the Trustee upon its request for all reasonable expenses, disbursements
        and advances incurred or made by the Trustee in accordance with any
        provision of this Indenture (including the reasonable compensation and
        the expenses and disbursements of its agents and counsel), except any
        such expense, disbursement or advance as may be attributable to its
        negligence or bad faith; and

                (3) to indemnify the Trustee for, and to hold it harmless
        against, any loss, liability or expense (including the reasonable
        compensation, expenses and disbursements of its agents, accountants,
        experts and counsel) incurred without negligence or bad faith on its
        part, arising out of or in connection with the acceptance or
        administration of this trust, including the costs and expenses of
        enforcing this Indenture against the Company (including, without
        limitation, this Section 607) and of defending itself against any claim
        (whether asserted by any Holder or the Company) or liability in
        connection with the exercise or performance of any of its powers or
        duties hereunder.

        As security for the performance of the obligations of the Company under
this Section 607, the Trustee shall have a lien prior to the Securities of every
series upon all property and funds held or collected by the Trustee, except
funds held in trust for the payment of principal of (and premium, if any) or
interest on particular series of Securities. The Trustee's right to





                                      -39-
<PAGE>   47

receive payment of any amounts due under this Section 607 shall not be
subordinate to any other liability or indebtedness of the Company (even though
the Securities may be so subordinated).

        When the Trustee incurs expenses or renders services after an Event of
Default specified in Section 501(9) or (10) occurs, the expenses and the
compensation for such services are intended to constitute expenses of
administration under Title 11, U.S. Code, or any similar Federal state or
foreign law for the relief of debtors.

SECTION 608.   Disqualification; Conflicting Interests.

        If the Trustee has or shall acquire a conflicting interest within the
meaning of the Trust Indenture Act, the Trustee shall either eliminate such
interest or resign, to the extent and in the manner provided by, and subject to
the provisions of, the Trust Indenture Act and this Indenture. To the extent
permitted by the Trust Indenture Act, the Trustee shall not be deemed to have a
conflicting interest by virtue of being a trustee under this Indenture with
respect to Securities of more than one series.

SECTION 609.   Corporate Trustee Required; Eligibility.

        There shall at all times be a Trustee hereunder with respect to the
Securities of each series which may be a Trustee hereunder for Securities of one
or more other series. Each Trustee shall be a Person that is eligible pursuant
to the Trust Indenture Act to act as such and has a combined capital and surplus
of at least $50,000,000 and its Corporate Trust Office in the Borough of
Manhattan, The City of New York, New York. If any Person publishes reports of
condition at least annually, pursuant to law or to the requirements of a
Federal, State, Territorial or District of Columbia supervising or examining
authority, then for the purposes of this Section, and to the extent permitted by
the Trust Indenture Act, the combined capital and surplus of such Person shall
be deemed to be its combined capital and surplus as set forth in its most recent
report of condition so published. If at any time the Trustee with respect to the
Securities of any series shall cease to be eligible in accordance with the
provisions of this Section, it shall resign immediately in the manner and with
the effect hereinafter specified in this Article.

SECTION 610.   Resignation and Removal; Appointment of Successor.

        (a) No resignation or removal of the Trustee and no appointment of a
successor Trustee pursuant to this Article shall become effective until the
acceptance of appointment by the successor Trustee under Section 611, at which
time the retiring Trustee shall be fully discharged from its obligations
hereunder.

        (b) A Trustee may resign at any time with respect to the Securities of
one or more series by giving written notice thereof to the Company. If an
instrument of acceptance by a successor Trustee shall not have been delivered to
the Trustee within 30 days after the giving of such notice of resignation, the
resigning Trustee may petition any court of competent jurisdiction for the
appointment of a successor Trustee with respect to the Securities of such
series.

        (c) A Trustee may be removed at any time with respect to the Securities
of any series by Act of the Holders of a majority in principal amount of the
Outstanding Securities of such series, delivered to the Trustee and to the
Company.






                                      -40-
<PAGE>   48

        (d) If at any time:

                (1) the Trustee shall fail to comply with Section 608 after
        written request therefor by the Company or by any Holder who has been a
        bona fide Holder of a Security of any series for at least six months, or

                (2) the Trustee shall cease to be eligible under Section 609 and
        shall fail to resign after written request therefor by the Company or by
        any such Holder, or

                (3) the Trustee shall become incapable of acting or shall be
        adjudged a bankrupt or insolvent or a receiver of the Trustee or of its
        property shall be appointed or any public officer shall take charge or
        control of the Trustee or of its property or affairs for the purpose of
        rehabilitation, conservation or liquidation,

then, in any such case, (i) the Company, by Board Resolution, may remove the
Trustee with respect to all Securities, or (ii) subject to Section 514, any
Holder who has been a bona fide Holder of a Security for at least six months
may, on behalf of himself and all others similarly situated, petition any court
of competent jurisdiction for the removal of the Trustee with respect to all
Securities and the appointment of a successor Trustee or Trustees.

        (e) If the Trustee shall resign, be removed or become incapable of
acting, or if a vacancy shall occur in the office of Trustee for any cause, with
respect to the Securities of one or more series, the Company, by Board
Resolution, shall promptly appoint a successor Trustee or Trustees with respect
to the Securities of that or those series (it being understood that any such
successor Trustee may be appointed with respect to the Securities of one or more
or all of such series and that at any time there shall be only one Trustee with
respect to the Securities of any particular series) and shall comply with the
applicable requirements of Section 611. If, within one year after such
resignation, removal or incapability, or the occurrence of such vacancy, a
successor Trustee with respect to the Securities of any series shall be
appointed by Act of the Holders of a majority in principal amount of the
Outstanding Securities of such series delivered to the Company and the retiring
Trustee, the successor Trustee so appointed shall, forthwith upon its acceptance
of such appointment in accordance with the applicable requirements of Section
611, become the successor Trustee with respect to the Securities of such series
and to that extent supersede the successor Trustee appointed by the Company. If
no successor Trustee with respect to the Securities of any series shall have
been so appointed by the Company or the Holders and accepted appointment in the
manner required by Section 611, any Holder who has been a bona fide Holder of a
Security of such series for at least six months may, on behalf of himself and
all others similarly situated, petition any court of competent jurisdiction for
the appointment of a successor Trustee with respect to the Securities of such
series.

        (f) The Company shall give notice of each resignation and each removal
of the Trustee with respect to the Securities of any series and each appointment
of a successor Trustee with respect to the Securities of any series to all
Holders of Securities of such series in the manner provided in Section 106. Each
notice shall include the name of the successor Trustee with respect to the
Securities of such series and the address of its Corporate Trust Office.





                                      -41-
<PAGE>   49

SECTION 611.   Acceptance of Appointment by Successor.

        In case of the appointment hereunder of a successor Trustee with respect
to all Securities, every such successor Trustee so appointed shall execute,
acknowledge and deliver to the Company and to the retiring Trustee an instrument
accepting such appointment, and thereupon the resignation or removal of the
retiring Trustee shall become effective and such successor Trustee, without any
further act, deed or conveyance, shall become vested with all the rights,
powers, trusts and duties of the retiring Trustee; but, on request of the
Company or the successor Trustee, such retiring Trustee shall, upon payment of
its charges, execute and deliver an instrument transferring to such successor
Trustee all the rights, powers and trusts of the retiring Trustee and shall duly
assign, transfer and deliver to such successor Trustee all property and money
held by such retiring Trustee hereunder.

        In case of the appointment hereunder of a successor Trustee with respect
to the Securities of one or more (but not all) series, the Company, the retiring
Trustee and each successor Trustee with respect to the Securities of one or more
series shall execute and deliver an indenture supplemental hereto wherein each
successor Trustee shall accept such appointment and which (1) shall contain such
provisions as shall be necessary or desirable to transfer and confirm to, and to
vest in, each successor Trustee all the rights, powers, trusts and duties of the
retiring Trustee with respect to the Securities of that or those series to which
the appointment of such successor Trustee relates, (2) if the retiring Trustee
is not retiring with respect to all Securities, shall contain such provisions as
shall be deemed necessary or desirable to confirm that all the rights, powers,
trusts and duties of the retiring Trustee with respect to the Securities of that
or those series as to which the retiring Trustee is not retiring shall continue
to be vested in the retiring Trustee, and (3) shall add to or change any of the
provisions of this Indenture as shall be necessary to provide for or facilitate
the administration of the trusts hereunder by more than one Trustee, it being
understood that nothing herein or in such supplemental indenture shall
constitute such Trustees co-trustees of the same trust and that each such
Trustee shall be trustee of a trust or trusts hereunder separate and apart from
any trust or trusts hereunder administered by any other such Trustee; and upon
the execution and delivery of such supplemental indenture the resignation or
removal of the retiring Trustee shall become effective to the extent provided
therein and each such successor Trustee, without any further act, deed or
conveyance, shall become vested with all the rights, powers, trusts and duties
of the retiring Trustee with respect to the Securities of that or those series
to which the appointment of such successor Trustee relates; but, on request of
the Company or any successor Trustee, such retiring Trustee shall duly assign,
transfer and deliver to such successor Trustee all property and money held by
such retiring Trustee hereunder with respect to the Securities of that or those
series to which the appointment of such successor Trustee relates.

        Upon request of any such successor Trustee, the Company shall execute
any and all instruments for more fully and certainly vesting in and confirming
to such successor Trustee all such rights, powers and trusts referred to in the
first or second preceding paragraph, as the case may be.






                                      -42-
<PAGE>   50

        No successor Trustee shall accept its appointment unless at the time of
such acceptance such successor Trustee shall be qualified and eligible under
this Article.

SECTION 612.   Merger, Conversion, Consolidation or Succession to Business.

        Any corporation into which the Trustee may be merged or converted or
with which it may be consolidated, or any corporation resulting from any merger,
conversion or consolidation to which the Trustee shall be a party, or any
corporation succeeding to all or substantially all the corporate trust business
of the Trustee, shall be the successor of the Trustee hereunder, provided that
such corporation shall be otherwise qualified and eligible under this Article,
without the execution or filing of any paper or any further act on the part of
any of the parties hereto. In case any Securities shall have been authenticated,
but not delivered, by the Trustee then in office, any successor by merger,
conversion or consolidation to such authenticating Trustee may adopt such
authentication and deliver the Securities so authenticated with the same effect
as if such successor Trustee had itself authenticated such Securities.

SECTION 613.   Preferential Collection of Claims Against the Company.

        If and when the Trustee shall be or become a creditor of the Company (or
any other obligor upon the Securities), the Trustee shall be subject to the
provisions of the Trust Indenture Act regarding the collection of claims against
the Company (or any such other obligor).

SECTION 614.   Appointment of Authenticating Agent.

        The Trustee may appoint an Authenticating Agent or Agents with respect
to one or more series of Securities which shall be authorized to act on behalf
of the Trustee to authenticate Securities of such series issued upon original
issue and upon exchange, registration of transfer or partial redemption thereof
or pursuant to Section 306, and Securities so authenticated shall be entitled to
the benefits of this Indenture and shall be valid and obligatory for all
purposes as if authenticated by the Trustee hereunder. Wherever reference is
made in this Indenture to the authentication and delivery of Securities by the
Trustee or the Trustee's certificate of authentication, such reference shall be
deemed to include authentication and delivery on behalf of the Trustee by an
Authenticating Agent and a certificate of authentication executed on behalf of
the Trustee by an Authenticating Agent. Each Authenticating Agent shall be
acceptable to the Company and shall at all times be a corporation organized and
doing business under the laws of the United States of America, any State thereof
or the District of Columbia, authorized under such laws to act as Authenticating
Agent, having a combined capital and surplus of not less than $50,000,000 and
subject to supervision or examination by Federal or State authority. If such
Authenticating Agent publishes reports of condition at least annually, pursuant
to law or to the requirements of said supervising or examining authority, then
for the purposes of this Section, the combined capital and surplus of such
Authenticating Agent shall be deemed to be its combined capital and surplus as
set forth in its most recent report of condition so published. If at any time an
Authenticating Agent shall cease to be eligible in accordance with the
provisions of this Section, such Authenticating Agent shall resign immediately
in the manner and with the effect specified in this Section.






                                      -43-
<PAGE>   51

        Any corporation into which an Authenticating Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or consolidation to which such Authenticating Agent
shall be a party, or any corporation succeeding to the corporate agency or
corporate trust business of an Authenticating Agent, shall continue to be an
Authenticating Agent, provided such corporation shall be otherwise eligible
under this Section, without the execution or filing of any paper or any further
act on the part of the Trustee or the Authenticating Agent.

        An Authenticating Agent may resign at any time by giving written notice
thereof to the Trustee and to the Company. The Trustee may at any time terminate
the agency of an Authenticating Agent by giving written notice thereof to such
Authenticating Agent and to the Company. Upon receiving such a notice of
resignation or upon such a termination, or in case at any time such
Authenticating Agent shall cease to be eligible in accordance with the
provisions of this Section, the Trustee may appoint a successor Authenticating
Agent which shall be acceptable to the Company and shall give notice of such
appointment in the manner provided in Section 106 to all Holders of Securities
of the series with respect to which such Authenticating Agent will serve. Any
successor Authenticating Agent upon acceptance of its appointment hereunder
shall become vested with all the rights, powers and duties of its predecessor
hereunder, with like effect as if originally named as an Authenticating Agent.
No successor Authenticating Agent shall be appointed unless eligible under the
provisions of this Section.

        The Trustee agrees to pay to each Authenticating Agent from time to time
reasonable compensation for its services under this Section, and the Trustee
shall be entitled to be reimbursed for such payments, subject to the provisions
of Section 607.

        If an appointment with respect to one or more series of Securities is
made pursuant to this Section, the Securities of such series may have endorsed
thereon, in lieu of the Trustee's certificate of authentication, an alternative
certificate of authentication in the following form:

        This is one of the Securities of the series designated therein referred
to in the within-mentioned Indenture.

                                          --------------------------------------
                                          As Trustee


                                          By
                                            ------------------------------------
                                          As Authenticating Agent


                                          By
                                            ------------------------------------
                                          Authorized Signatory






                                      -44-
<PAGE>   52


                                  ARTICLE SEVEN

              HOLDERS' LISTS AND REPORTS BY TRUSTEE AND THE COMPANY

SECTION 701.   Company to Furnish Trustee Names and Addresses of Holders.

        The Company will furnish or cause to be furnished to the Trustee

        (a) semi-annually, not more than 15 days after each Regular Record Date,
a list, in such form as the Trustee may reasonably require, of the names and
addresses of the Holders of Securities of each series as of such Regular Record
Date, and

        (b) at such other times as the Trustee may request in writing, within 30
days after the receipt by the Company of any such request, a list of similar
form and content as of a date not more than 15 days prior to the time such list
is furnished;

excluding from any such list names and addresses received by the Trustee in its
capacity as Security Registrar.

SECTION 702.   Preservation of Information; Communications to Holders.

        (a) The Trustee shall preserve, in as current a form as is reasonably
practicable, the names and addresses of Holders contained in the most recent
list furnished to the Trustee as provided in Section 701 and the names and
addresses of Holders received by the Trustee in its capacity as Security
Registrar. The Trustee may destroy any list furnished to it as provided in
Section 701 upon receipt of a new list so furnished.

        (b) The rights of Holders to communicate with other Holders with respect
to their rights under this Indenture or under the Securities, and the
corresponding rights and duties of the Trustee, shall be as provided by the
Trust Indenture Act.

        (c) Every Holder of Securities, by receiving and holding the same,
agrees with the Company and the Trustee that none of the Company, the Trustee or
any agent of any of them shall be held accountable by reason of any disclosure
of information as to names and addresses of Holders made pursuant to the Trust
Indenture Act.

SECTION 703.   Reports by Trustee.

        (a) The Trustee shall transmit to Holders such reports concerning the
Trustee and its actions under this Indenture as may be required pursuant to the
Trust Indenture Act at the times and in the manner provided pursuant thereto.

        (b) A copy of each such report shall, at the time of such transmission
to Holders, be filed by the Trustee with each stock exchange upon which any
Securities are listed, with the Commission and with the Company. The Company
will notify the Trustee when any Securities are listed on any stock exchange.







                                      -45-
<PAGE>   53

SECTION 704.   Reports by Company.

        The Company shall file with the Trustee and the Commission, and transmit
to Holders, such information, documents and other reports, and such summaries
thereof, as may be required pursuant to the Trust Indenture Act at the times and
in the manner provided pursuant to such Act and in the manner set forth in
Section 1017; provided that any such information, documents or reports required
to be filed with the Commission pursuant to Section 13 or 15(d) of the Exchange
Act ("SEC Reports") shall be filed with the Trustee within 15 days after the
same is so required to be filed with the Commission. In the event the Company
shall cease to be required to file SEC Reports pursuant to the Exchange Act, the
Company will nonetheless continue to file such reports with the Commission
(unless the Commission will not accept such a filing) and the Trustee and to
furnish copies of such SEC Reports to the Holders of Securities at the time the
Company is required to file such reports with the Trustee and will make such
information available to investors who request it in writing.

                                ARTICLE EIGHT

                         MERGER, CONSOLIDATION, ETC.

SECTION 801.   Mergers, Consolidations and Certain Sales of Assets.

        (a) The Company may not, in a single transaction or a series of related
transactions, (i) consolidate with or merge into any other Person or permit any
other Person to consolidate with or merge into the Company (other than a
consolidation or merger of a Wholly-Owned Restricted Subsidiary organized under
the laws of a State of the United States into the Company), or (ii) directly or
indirectly, transfer, sell, lease or otherwise dispose of (other than (A) any
transfer, sale, lease or disposition from any Restricted Subsidiary to another
Restricted Subsidiary, or (B) a transfer of any ownership or membership interest
in any Restricted Subsidiary from the Company to any Restricted Subsidiary) all
or substantially all of its assets (determined on a consolidated basis for the
Company and its Restricted Subsidiaries taken as a whole and provided that the
creation of a Lien on or in any of its assets shall not in and of itself
constitute the transfer, sale, lease or disposition of the assets subject to the
Lien), unless: (1) in a transaction in which the Company does not survive or in
which the Company sells, leases or otherwise disposes of all or substantially
all of its assets to any other Person, the successor entity to the Company shall
be a corporation, limited liability company, partnership or trust organized
under the laws of the United States of America or any State thereof or the
District of Columbia and shall expressly assume, by a supplemental indenture
executed and delivered to the Trustee in form satisfactory to the Trustee, all
of the Company's obligations under this Indenture; (2) immediately after giving
pro forma effect to such transaction as if such transaction had occurred at the
beginning of the last full fiscal quarter immediately prior to the consummation
of such transaction with the appropriate adjustments with respect to the
transaction being included in such pro forma calculation and treating any Debt
which becomes an obligation of the Company or a Subsidiary as a result of such
transaction as having been Incurred by the Company or such Subsidiary at the
time of the transaction, no Default or Event of Default shall have occurred and
be continuing; (3) immediately after giving effect to such transaction, the
Consolidated Net Worth of the Company (or other successor entity to the Company)
is equal to or greater than that of the Company immediately prior to the
transaction; (4) if, as a result of any such transaction,






                                      -46-

<PAGE>   54

property or assets of the Company would become subject to a Lien prohibited by
the provisions of any indenture supplemental hereto, the Company or the
successor entity to the Company shall have secured the Securities as required by
such supplemental indenture; (5) the Company has delivered to the Trustee an
Officer's Certificate and an Opinion of Counsel, each in form and substance
satisfactory to the Trustee stating that such consolidation, merger, conveyance,
transfer, lease or acquisition and, if a supplemental indenture is required in
connection with such transaction, such supplemental indenture, complies with
this Article and that all conditions precedent herein provided for relating to
such transaction have been complied with, and, with respect to such Officer's
Certificate, setting forth the manner of determination of the Consolidated Net
Worth in accordance with Clause (3) of this Section 801(a), of the Company or,
if applicable, of the Successor Company as required pursuant to the foregoing.

        (b) In the event of any transaction (other than a lease) described in
and complying with the immediately preceding paragraph in which the Company is
not the surviving Person and the surviving Person assumes all the obligations of
the Company under the Securities and this Indenture pursuant to a supplemental
indenture, such surviving Person shall succeed to, and be substituted for, and
may exercise every right and power of, the Company, and the Company will be
discharged from its obligations under this Indenture and the Securities.

SECTION 802.   Successor Substituted.

        Upon any consolidation of the Company with, or merger of the Company
with or into, any other Person or any conveyance, transfer or lease of the
properties and assets of the Company substantially as an entirety in accordance
with Section 801, the successor Person formed by such consolidation or into
which the Company is merged or to which such conveyance, transfer or lease is
made shall succeed to, and be substituted for, and may exercise every right and
power of, the Company under this Indenture with the same effect as if such
successor Person had been named as the Company herein, and thereafter, except in
the case of a lease, the predecessor Person shall be relieved of all obligations
and covenants under this Indenture and the Securities.

                                  ARTICLE NINE

                            SUPPLEMENTAL INDENTURES

SECTION 901.   Supplemental Indentures Without Consent of Holders.

        Without the consent of any Holders, the Company, when authorized by
Board Resolution, and the Trustee, at any time and from time to time, may enter
into one or more indentures supplemental hereto, in form satisfactory to the
Trustee, for any of the following purposes:

                (1) to evidence the succession of another Person to the Company
        and the assumption by any such successor of the covenants of the Company
        in this Indenture and in the Securities; or

                (2) make any change (including, but not limited to, adding to
        the covenants of the Company or adding additional Events of Default)
        that would provide any additional






                                      -47-
<PAGE>   55



        rights or benefits to the Holders of all or any series of Securities
        (and if such covenants are to be for the benefit of less than all series
        of Securities, stating that such covenants are expressly being included
        solely for the benefit of such series) or that does not adversely affect
        the legal rights under the Indenture of any such Holder in any material
        respect, or to surrender any right or power herein conferred upon the
        Company; or

                (3) to secure all or any series of the Securities as provided as
        contemplated by Section 301 or otherwise; or

                (4) to modify, eliminate or add to the provisions of this
        Indenture to such extent as shall be necessary to comply with any
        requirement of the Commission in order to maintain the qualification of
        this Indenture under the Trust Indenture Act;

                (5) to add to, change or eliminate any of the provisions of this
        Indenture in respect of one or more series of Securities, provided that
        any such addition, change or elimination (A) shall neither (i) apply to
        any Security of any series created prior to the execution of such
        supplemental indenture and entitled to the benefit of such provision nor
        (ii) modify the rights of the Holder of any such Security with respect
        to such provision or (B) shall become effective only when there is no
        such Security Outstanding; or

                (6) to cure any ambiguity, to correct or supplement any
        provision herein which may be inconsistent with any other provision
        herein, or to make any other provisions with respect to matters or
        questions arising under this Indenture which shall not be inconsistent
        with the provisions of this Indenture, provided that such action
        pursuant to this Clause (6) shall not adversely affect the legal rights
        of the Holders of Securities of any relevant series; or

                (7) to provide for or facilitate the issuance of Securities in
        bearer form registrable or not registrable as to principal, and with or
        without interest coupons, or to provide for or facilitate the issuance
        of uncertificated Securities in addition to or in place of certificated
        Securities; or

                (8) to establish the form or terms of Securities of any series
        as permitted by Sections 201 or 301; or

                (9) to evidence and provide for the acceptance of appointment
        hereunder by a successor trustee with respect to the Securities of one
        or more series and to add or to change any of the provisions of this
        Indenture as may be necessary to provide for or facilitate the
        administration of the trusts hereunder by more than one Trustee, subject
        to the requirements of Section 611.

SECTION 902.   Supplemental Indentures with Consent of Holders.

        After receipt of the Required Consent, given by Act of those Persons
giving the Required Consent delivered to the Company and the Trustee, and
consistent with Section 513, the Company, when authorized by Board Resolution,
and the Trustee may enter into an indenture or indentures supplemental hereto
for the purpose of adding any provisions to or changing in any manner or
eliminating any of the provisions of this Indenture or modifying in any manner
the rights of the Holders of Securities of relevant series under this Indenture;
provided, however, that






                                      -48-
<PAGE>   56

no such supplemental indenture shall, without the consent of the Holder of each
Outstanding Security affected thereby,

                (1) change the due date of the principal of, or any installment
        of interest on, any Security, or reduce the principal amount thereof or
        the rate of interest thereon or any premium payable thereon, or change
        the place of payment where, or the coin or currency in which, any
        Security or any premium or interest thereon is payable, or impair the
        right to institute suit for the enforcement of any such payment on or
        after the due date thereof (or, in the case of redemption, on or after
        the Redemption Date), or, in the case of an Offer to Purchase which has
        been made, on or after the applicable Purchase Date, or

                (2) reduce the percentage in principal amount of the Outstanding
        Securities of any series, the consent of whose Holders is required for
        any such supplemental indenture, or the consent of whose Holders is
        required for any waiver (of compliance with certain provisions of this
        Indenture or certain defaults hereunder and their consequences) provided
        for in this Indenture, or

                (3) modify any of the provisions of this Section, Section 513 or
        Section 1019, except to increase any such percentage or to provide that
        certain other provisions of this Indenture cannot be modified or waived
        without the consent of the Holder of each Outstanding Security affected
        thereby, or

                (4) following the mailing of an Offer with respect to an Offer
        to Purchase and until the Expiration Date of such Offer to Purchase,
        modify the provisions of this Indenture with respect to such Offer to
        Purchase in a manner materially adverse to such Holder.


        A supplemental indenture which changes or eliminates any covenant or
other provision of this Indenture that has expressly been included solely for
the benefit of one or more particular series of Securities, or which modifies
the rights of the Holders of Securities of such series with respect to such
covenant or other provision, shall be deemed not to affect the rights under
this Indenture of the Holders of Securities of any other series.

        It shall not be necessary for any Act of Holders under this Section to
approve the particular form of any proposed supplemental indenture, but it shall
be sufficient if such Act shall approve the substance thereof.

        Notwithstanding anything to the contrary in this Section 902, no
consent of Holders of Securities shall be required for the Company to enter
into a supplemental indenture pursuant to Section 901.

SECTION 903.   Execution of Supplemental Indentures.

        In executing, or accepting the additional trusts created by, any
supplemental indenture permitted by this Article or the modifications thereby of
the trusts created by this Indenture, the Trustee shall be entitled to receive,
and (subject to Section 601) shall be fully protected in relying upon, an
Opinion of Counsel stating that the execution of such supplemental indenture is
authorized or permitted by this Indenture. The Trustee may, but shall not be
obligated to, enter into any such supplemental indenture which affects the
Trustee's own rights, duties or immunities under this Indenture or otherwise.

SECTION 904.   Effect of Supplemental Indentures.

        Upon the execution of any supplemental indenture under this Article,
this Indenture shall be modified in accordance therewith, and such supplemental
indenture shall form a part of this Indenture for all purposes; and every Holder
of Securities theretofore or thereafter authenticated and delivered hereunder
shall be bound thereby.






                                      -49-
<PAGE>   57


SECTION 905.   Conformity with Trust Indenture Act.

        Every supplemental indenture executed pursuant to this Article shall
conform to the requirements of the Trust Indenture Act.

SECTION 906.   Reference in Securities to Supplemental Indentures.

        Securities of any series authenticated and delivered after the execution
of any supplemental indenture pursuant to this Article may, and shall if
required by the Trustee, bear a notation in form approved by the Trustee as to
any matter provided for in such supplemental indenture. If the Company shall so
determine, new Securities of any series so modified as to conform, in the
opinion of the Trustee and the Company, to any such supplemental indenture may
be prepared and executed by the Company and authenticated and delivered by the
Trustee in exchange for Outstanding Securities of such series.

                                  ARTICLE TEN

                                   COVENANTS

SECTION 1001.   Payment of Principal, Premium and Interest

        The Company will, for the benefit of each series of Securities, duly and
punctually pay the principal of and premium, if any, and interest on the
Securities of that series in accordance with the terms of the Securities and
this Indenture.

SECTION 1002.   Maintenance of Office or Agency.

        The Company will maintain in the Borough of Manhattan, The City of New
York, New York, an office or agency where Securities of any series may be
presented or surrendered for payment, where Securities of any series may be
surrendered for registration of transfer or exchange and where notices and
demands to or upon the Company in respect of the Securities of any series and
this Indenture may be served. The Company will 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, and the Company hereby appoints the
Trustee as its agent to receive all such presentations, surrenders, notices and
demands.

        The Company may also from time to time designate one or more other
offices or agencies (in or outside the Borough of Manhattan, The City of New
York, New York) where the Securities of one or more series 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, New York for such purposes.
The Company will 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.






                                      -50-
<PAGE>   58

SECTION 1003.   Money for Security Payments to be Held in Trust.

        If the Company shall at any time act as its own Paying Agent with
respect to any series of Securities, it will, on or before each due date of the
principal of (and premium, if any) or interest on any Securities of that series,
segregate and hold in trust for the benefit of the Persons entitled thereto a
sum sufficient to pay the principal (and premium, if any) or interest so
becoming due until such sums shall be paid to such Persons or otherwise disposed
of as herein provided and will promptly notify the Trustee in writing of its
action or failure so to act. As provided in Section 504, upon any bankruptcy or
reorganization proceeding relative to the Company, the Trustee shall serve as
the Paying Agent for the Securities.

        Whenever the Company shall have one or more Paying Agents for any series
of Securities, it will, prior to each due date of the principal of (and premium,
if any) or interest on any Securities of that series, deposit with a Paying
Agent a sum sufficient to pay the principal (and premium, if any) or interest so
becoming due, such sum to be held in trust for the benefit of the Persons
entitled to such principal, premium or interest, and (unless such Paying Agent
is the Trustee) the Company will promptly notify the Trustee in writing of its
action or failure so to act. As provided in Section 504, upon any bankruptcy or
reorganization proceeding relative to the Company the Trustee shall serve as the
Paying Agent for the Securities.

        The Company will cause each Paying Agent for any series of Securities
other than the Trustee to execute and deliver to the Trustee an instrument in
which such Paying Agent shall agree with the Trustee, subject to the provisions
of this Section, that such Paying Agent will:

                (1) hold all sums held by it for the payment of the principal of
        (and premium, if any) or interest on Securities in trust for the benefit
        of the Persons entitled thereto until such sums shall be paid to such
        Persons or otherwise disposed of as herein provided;

                (2) give the Trustee notice of any default by the Company (or
        any other obligor upon the Securities of such series) in the making of
        any payment of principal (and premium, if any) or interest with respect
        to Securities of such series;

                (3) at any time during the continuance of any such default, upon
        the written request of the Trustee, forthwith pay to the Trustee all
        sums so held in trust by such Paying Agent for payment in respect of the
        Securities of that series; and

                (4) acknowledge, accept and agree to comply in all respects with
        the provisions of this Indenture relating to the duties, rights and
        obligations of such Paying Agent.

        The Company may at any time, for the purpose of obtaining the
satisfaction and discharge of this Indenture or for any other purpose, pay, or
by Company Order direct any Paying Agent to pay, to the Trustee all sums held in
trust by the Company or such Paying Agent, such sums to be held by the Trustee
upon the same trusts as those upon which such sums were held by the Company or
such Paying Agent; and, upon such payment by any Paying Agent to the Trustee,
such Paying Agent shall be released from all further liability with respect to
such money.






                                      -51-
<PAGE>   59

        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 (and premium, if
any) or interest on any Security of any series and remaining unclaimed for two
years after such principal (and premium, if any) or interest has become due and
payable shall be paid to the Company on the Company Request, or (if then held by
the Company) shall be discharged from such trust; and the Holder of such
Security shall thereafter, as an unsecured general creditor, 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 a newspaper published in
the English language, customarily published on each Business Day and of general
circulation in the Borough of Manhattan, The City of New York, New York, 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 publication, any
unclaimed balance of such money then remaining will be repaid to the Company.

SECTION 1004.   Existence.

        Subject to Article Eight, the Company will do or cause to be done all
things necessary to preserve and keep in full force and effect its existence,
rights (charter and statutory) and franchises; provided, however, that the
Company shall not be required to preserve any such right or franchise 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 that the loss
thereof is not disadvantageous in any material respect to the Holders.

SECTION 1005.   Maintenance of Properties.

        The Company will cause all properties material to the conduct of its and
its Restricted Subsidiaries' business taken as a whole, to be maintained and
kept in good condition, repair and working order and supplied with all necessary
equipment and will cause to be made all necessary repairs, renewals,
replacements, betterments and improvements thereof, all as in the judgment of
the Company may be necessary so that the business carried on in connection
therewith may be properly and advantageously conducted at all times; provided,
however, that nothing in this Section shall prevent the Company from
discontinuing the operation or maintenance of any of such properties if such
discontinuance is, as determined in the good faith judgment of the Company,
desirable in the conduct of its business or, in the case of the Company, the
business of any Subsidiary, and not disadvantageous in any material respect to
the Holders.

SECTION 1006.   Payment of Taxes and Other Claims.

        The Company will pay or discharge or cause to be paid or discharged,
before the same shall become delinquent,

                (1) all taxes, assessments and governmental charges levied or
        imposed upon the Company or any Subsidiaries of the Company or upon the
        income, profits or property of the Company or any Subsidiaries, and






                                      -52-
<PAGE>   60

                (2) all lawful claims for labor, materials and supplies which,
        if unpaid, might by law become a lien upon the property of the Company
        or any Subsidiaries of the Company; provided, however, that the Company
        shall not be required to pay or discharge or cause to be paid or
        discharged any such tax, assessment, charge or claim whose amount,
        applicability or validity is being contested in good faith by
        appropriate proceedings.

SECTION 1007.   [intentionally omitted].

SECTION 1008.   [intentionally omitted].

SECTION 1009.   [intentionally omitted].

SECTION 1010.   [intentionally omitted].

SECTION 1011.   [intentionally omitted].

SECTION 1012.   [intentionally omitted].

SECTION 1013.   [intentionally omitted].

SECTION 1014.   [intentionally omitted].

SECTION 1015.   [intentionally omitted].

SECTION 1016.   Change of Control.

        (a) Within 30 days of the occurrence of a Change of Control, the Company
will be required to make an Offer to Purchase all Outstanding Securities at a
purchase price equal to 101% of their principal amount plus accrued and unpaid
interest to the date of purchase.

        (b) The Company and Trustee shall perform their respective obligations
specified in the Offer for the Offer to Purchase. On or prior to the Purchase
Date, the Company shall

                (i)   accept for payment Securities or portions thereof tendered
        pursuant to the Offer,

                (ii)  deposit with the Paying Agent (or, if the Company is
        acting as its own Paying Agent, segregate and hold in trust as
        provided in Section 1003) money sufficient to pay the purchase price of
        all Securities or portions thereof so accepted and

                (iii) deliver or cause to be delivered to the Trustee all
        Securities so accepted together with an Officers' Certificate stating
        the Securities or portions thereof accepted for payment by the Company.
        The Paying Agent shall promptly mail or deliver to Holders of Securities
        so accepted payment in an amount equal to the purchase price, and the
        Trustee shall promptly authenticate and mail or deliver to such Holders
        a new Security or Securities equal in principal amount to any
        unpurchased portion of the





                                      -53-
<PAGE>   61

        Security surrendered as requested by the Holder. Any Security not
        accepted for payment shall be promptly mailed or delivered by the
        Company to the Holder thereof.

        (c) A "Change of Control" will be deemed to have occurred at such time
as either

                (i)   any Person or any Persons acting together that would
        constitute a "group" (a "Group") for purposes of Section 13(d) of the
        Exchange Act, or any successor provision thereto (other than Eagle
        River, Mr. Craig O. McCaw and their respective Affiliates or an
        underwriter engaged in a firm commitment underwriting on behalf of the
        Company), shall beneficially own (within the meaning of Rule 13d-3 under
        the Exchange Act, or any successor provision thereto) more than 50% of
        the aggregate voting power of all classes of Voting Stock of the
        Company; or

                (ii)  neither Mr. Craig O. McCaw nor any person designated by
        him to the Company as acting on his behalf shall be a director of the
        Company; or

                (iii) during any period of two consecutive years, individuals
        who at the beginning of such period constituted the Board of Directors
        (together with any new directors whose election by the Board of
        Directors or whose nomination for election by the shareholders of the
        Company was proposed by a vote of a majority of the directors of the
        Company then still in office who were either directors at the beginning
        of such period or whose election or nomination for election was
        previously so approved) cease for any reason to constitute a majority of
        the Board of Directors then in office.

        (d) In the event that the Company makes an Offer to Purchase the
Securities, the Company intends to comply with any applicable securities laws
and regulations, including any applicable requirements of Section 14(e) of, and
Rule 14e-1 under, the Exchange Act.

        (e) Unless the Company defaults in the payment of the Purchase Price,
any Security accepted for payment pursuant to an Offer to Purchase shall cease
to accrue interest after the Purchase Date.

SECTION 1017.   Provision of Financial Information.

        The Company has agreed to file with the Trustee, within 15 days after it
files them with the Commission, copies of the SEC Reports. In the event the
Company shall cease to be required to file SEC Reports pursuant to the Exchange
Act, the Company will nevertheless continue to file such reports with the
Commission (unless the Commission will not accept such a filing) and the
Trustee. The Company will furnish copies of the SEC Reports to the Holders of
Securities at the time the Company is required to file the same with the Trustee
and will make such information available to investors who request it in writing.

SECTION 1018.   Statement by Officers as to Default.

        (a) The Company will deliver to the Trustee, within 120 days after the
end of each quarter of each fiscal year of the Company ending after the date
hereof, an Officers' Certificate, stating whether or not to the best knowledge
of the signers thereof the Company is in default in the performance and
observance of any of the terms, provisions and conditions of this Indenture





                                      -54-
<PAGE>   62

and if the Company shall be in default, specifying all such defaults and the
nature and status thereof of which they may have knowledge.

        (b) The Company shall deliver to the Trustee, as soon as possible and in
any event within 10 days after the Company becomes aware of the occurrence of a
Default or an Event of Default, an Officers' Certificate setting forth the
details of such Default or Event of Default and the action which the Company
proposes to take with respect thereto.

SECTION 1019.   Waiver of Certain Covenants.

        Except as otherwise specified as contemplated by Section 301 for
Securities of such series, the Company may, with respect to the Securities of
any series, omit in any particular instance to comply with any covenant or
condition set forth in Sections 1004 through 1017, inclusive, if by giving the
Required Consent before or after the time for such compliance, those Persons
giving the Required Consent shall, by Act of such Persons, either waive such
compliance in such instance or generally waive compliance with such covenant or
condition, but no such waiver shall extend to or affect such covenant or
condition except to the extent so expressly waived, and, until such waiver shall
become effective, the obligations of the Company and the duties of the Trustee
in respect of any such covenant or condition shall remain in full force and
effect.

                                 ARTICLE ELEVEN

                            REDEMPTION OF SECURITIES

SECTION 1101.   Applicability of Article.

        Securities of any series which are redeemable before their Stated
Maturity shall be redeemable in accordance with their terms and (except as
otherwise specified as contemplated by Section 301 for such Securities) in
accordance with this Article.

SECTION 1102.   Election to Redeem; Notice to Trustee.

        The election of the Company to redeem any Securities of any series shall
be evidenced by a Board Resolution or in another manner specified as
contemplated by Section 301 for such Securities. In case of any redemption at
the election of the Company of less than all the Securities of any series
(including any such redemption affecting only a single Security), the Company
shall, at least 60 days prior to the Redemption Date fixed by the Company
(unless a shorter notice shall be satisfactory to the Trustee), notify the
Trustee of such Redemption Date, of the principal amount of Securities of such
series to be redeemed and, if applicable, of the tenor of the Securities to be
redeemed. In the case of any redemption of Securities prior to the expiration of
any restriction on such redemption provided in the terms of such Securities or
elsewhere in this Indenture, the Company shall furnish the Trustee with an
Officers' Certificate evidencing compliance with such restriction.







                                      -55-
<PAGE>   63

SECTION 1103.   Selection by Trustee of Securities to Be Redeemed.

        If less than all the Securities of any series are to be redeemed (unless
all the Securities of such series and of a specified tenor are to be redeemed or
unless such redemption affects only a single Security), the particular
Securities to be redeemed shall be selected not more than 60 days prior to the
Redemption Date by the Trustee, from the Outstanding Securities of such series
not previously called for redemption, by such method as the Trustee shall deem
fair and appropriate and which may provide for the selection for redemption of a
portion of the principal amount of any Security of such series, provided that
the unredeemed portion of the principal amount of any Security of such series
shall be in an authorized denomination (which shall not be less than the minimum
authorized denomination) for such Security. If less than all the Securities of
such series and of a specified tenor are to be redeemed (unless such redemption
affects only a single Security), the particular Securities to be redeemed shall
be selected not more than 60 days prior to the Redemption Date by the Trustee,
from the Outstanding Securities of such series and specified tenor not
previously called for redemption in accordance with the preceding sentence.

        The Trustee shall promptly notify the Company in writing of the
Securities selected for redemption as aforesaid and, in case of any Securities
selected for partial redemption as aforesaid, the principal amount thereof to be
redeemed.

        The provisions of the two preceding paragraphs shall not apply with
respect to any redemption affecting only a single Security, whether such
Security is to be redeemed in whole or in part. In the case of any such
redemption in part, the unredeemed portion of the principal amount of the
Security shall be in an authorized denomination (which shall not be less than
the minimum authorized denomination) for such Security.

        For all purposes of this Indenture, unless the context otherwise
requires, all provisions relating to the redemption of Securities shall relate,
in the case of any Securities redeemed or to be redeemed only in part, to the
portion of the principal amount of such Securities which has been or is to be
redeemed.


SECTION 1104.   Notice of Redemption.

        Notice of redemption shall be given by first-class mail, postage
prepaid, mailed not less than 30 nor more than 60 days prior to the Redemption
Date, to each Holder of Securities to be redeemed, at such Holder's address
appearing in the Security Register.

        All notices of redemption shall state:

                (1) the Redemption Date,

                (2) the Redemption Price,

                (3) if less than all the Outstanding Securities of any series
        consisting of more than a single Security are to be redeemed, the
        identification (and, in the case of partial redemption of any such
        Securities, the principal amounts) of the particular Securities to be
        redeemed and, if less than all the Outstanding Securities of any series
        consisting of a single Security are to be redeemed, the principal amount
        of the particular Security to be redeemed,

                (4) that on the Redemption Date the Redemption Price will become
        due and payable upon each such Security to be redeemed and that interest
        thereon will cease to accrue on and after said date,

                (5) the place or places where such Securities are to be
        surrendered for payment of the Redemption Price,






                                      -56-
<PAGE>   64

                (6) that in the case that a Security of any series is only
        redeemed in part, the Company shall execute and the Trustee shall
        authenticate and deliver to the Holder of such Security without service
        charge, a new Security or Securities of that series in an aggregate
        amount equal to the unredeemed portion of the Security,

                (7) the aggregate principal amount of Securities being redeemed,
        and

                (8) the CUSIP number or numbers of the Securities being
        redeemed.

        Notice of redemption of Securities to be redeemed at the election of the
Company shall be given by the Company or, if request is made to the Trustee no
less than 35 days prior to the Redemption Date, by the Trustee in the name and
at the expense of the Company.

SECTION 1105.   Deposit of Redemption Price.

        Prior to any Redemption Date, the Company shall deposit with the Trustee
or with a Paying Agent (or, if the Company is acting as its own Paying Agent,
segregate and hold in trust as provided in Section 1003) an amount of money
sufficient to pay the Redemption Price of, and (except if the Redemption Date
shall be an Interest Payment Date) accrued and unpaid interest on, all the
Securities which are to be redeemed on that date.

SECTION 1106.   Securities Payable on Redemption Date.

        Notice of redemption having been given as aforesaid, the Securities so
to be redeemed shall, on the Redemption Date, become due and payable at the
Redemption Price therein specified, and from and after such date (unless the
Company shall default in the payment of the Redemption Price and accrued and
unpaid interest) such Securities shall cease to bear interest. Upon surrender of
any such Security for redemption in accordance with said notice, such Security
shall be paid by the Company at the Redemption Price, together with accrued and
unpaid interest to the Redemption Date; provided, however, that, unless
otherwise specified as contemplated by Section 301, installments of interest
whose Stated Maturity is on or prior to the Redemption Date will be payable to
the Holders of such Securities, or one or more Predecessor Securities,
registered as such at the close of business on the relevant Record Dates
according to their terms and the provisions of Section 307.

        If any Security called for redemption shall not be so paid upon
surrender thereof for redemption, the principal (and premium, if any) shall,
until paid, bear interest from the Redemption Date at the rate provided by the
Security.

SECTION 1107.   Securities Redeemed in Part.

        Any Security which is to be redeemed only in part shall be surrendered
at an office or agency of the Company designated for that purpose pursuant to
Section 1002 (with, if the Company or the Trustee so requires, due endorsement
by, or a written instrument of transfer in form satisfactory to the Company and
the Trustee duly executed by, the Holder thereof or his attorney duly authorized
in writing), and the Company shall execute, and the Trustee shall authenticate
and deliver to the Holder of such Security without service charge, a new
Security or Securities of the same series and of like tenor, of any authorized
denomination as requested by






                                      -57-
<PAGE>   65

such Holder, in aggregate principal amount equal to and in exchange for the
unredeemed portion of the principal of the Security so surrendered. If a Global
Security is so surrendered, such new Security shall also be a Global Security.

                                 ARTICLE TWELVE

                       DEFEASANCE AND COVENANT DEFEASANCE

SECTION 1201.   Company's Option to Effect Defeasance or Covenant Defeasance.

        The Company may elect, at its option at any time, to have Section 1202
or Section 1203 applied to any Securities or any series of Securities, as the
case may be, designated pursuant to Section 301 as being defeasible pursuant to
such Section 1202 or 1203, in accordance with any applicable requirements
provided pursuant to Section 301 and upon compliance with the conditions set
forth below in this Article. Any such election shall be evidenced by a Board
Resolution or in another manner specified as contemplated by Section 301 for
such Securities.

SECTION 1202.   Defeasance and Discharge.

        Upon the Company's exercise of the option provided in Section 1201
applicable to this Section, the Company shall be deemed to have been discharged
from its obligations with respect to the Outstanding Securities or any series of
Outstanding Securities, as the case may be, on the date the conditions set forth
below are satisfied (hereinafter, "defeasance"). For this purpose, such
defeasance means that the Company shall be deemed to have paid and discharged
the entire indebtedness represented by the Outstanding Securities or any series
of Outstanding Securities, as the case may be, and to have satisfied all its
other obligations under such Securities and this Indenture insofar as such
Securities are concerned (and the Trustee, at the expense of the Company, shall
execute proper instruments acknowledging the same), except for the following
which shall survive until otherwise terminated or discharged hereunder:

                (A) the rights of Holders of the Outstanding Securities or the
        relevant series of Outstanding Securities, as the case may be, to
        receive, solely from the trust fund described in Section 1204 and as
        more fully set forth in such Section, payments in respect of the
        principal of (and premium, if any) and interest on such Securities when
        such payments are due,

                (B) the Company's obligations with respect to such Securities
        under Sections 304, 305, 306, 1002 and 1003,

                (C) the rights, powers, trusts, duties and immunities of the
        Trustee hereunder and

                (D) this Article Twelve.

        Subject to compliance with this Article Twelve, the Company may exercise
its option under this Section 1202 notwithstanding the prior exercise of its
option under Section 1203.






                                      -58-
<PAGE>   66

SECTION 1203.   Covenant Defeasance.

        Upon the Company's exercise of the option provided in Section 1201
applicable to this Section

                (i)  the Company shall be released from its obligations under
        Sections 1005 through 1017, inclusive, and Section 801, with respect to
        the Outstanding Securities or any series of Outstanding Securities, as
        the case may be,

                (ii) the occurrence of an event specified in Sections 501(3),
        501(5), 501 (6) (with respect to Sections 1005 through 1017, inclusive)
        and 501(7) with respect to the Outstanding Securities or any series of
        Outstanding Securities, as the case may be, shall not be deemed to be an
        Event of Default, on and after the date the conditions set forth below
        are satisfied (hereinafter, "covenant defeasance"). For this purpose,
        such covenant defeasance means that 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 Section or Article, whether directly or
        indirectly by reason of any reference elsewhere herein to any such
        Section or Article or by reason of any reference in any such Section or
        Article to any other provision herein or in any other document, but the
        remainder of this Indenture and such Securities shall be unaffected
        thereby.

SECTION 1204.   Conditions to Defeasance or Covenant Defeasance.

        The following shall be the conditions to application of either Section
1202 or Section 1203 to the Outstanding Securities or any series of Outstanding
Securities, as the case may be:

                (1) The Company shall irrevocably have deposited or caused to be
        deposited with the Trustee as trust funds in trust for the purpose of
        making the following payments, specifically pledged as security for, and
        dedicated solely to, the benefit of the Holders of such Securities,

                        (A) money in an amount, or

                        (B) U.S. Government Obligations which through the
                scheduled payment of principal and interest in respect thereof
                in accordance with their terms will provide, not later than one
                day before the due date of any payment, money in an amount, or

                        (C) a combination thereof, sufficient, in the opinion of
                a nationally recognized firm of independent certified public
                accountants expressed in a written certification thereof
                delivered to the Trustee, to pay and discharge, and which shall
                be applied by the Trustee to pay and discharge, the principal
                of, premium, if any, and each installment of interest on the
                Securities on the days on which such payments are due and
                payable in accordance with the terms of this Indenture and of
                such Securities as established as contemplated by Section 301.
                For this purpose, "U.S. Government Obligations" means securities
                that are






                                      -59-
<PAGE>   67



                            (x) direct obligations of the United States of
                    America for the payment of which its full faith and credit
                    is pledged or

                            (y) obligations of a Person controlled or
                    supervised by and acting as an agency or instrumentality of
                    the United States of America the payment of which is
                    unconditionally guaranteed as a full faith and credit
                    obligation by the United States of America, which, in
                    either case, are not callable or redeemable at the option
                    of the issuer thereof, and shall also include a depositary
                    receipt issued by a bank (as defined in Section 3(a)(2) of
                    the Securities Act) as custodian with respect to any such
                    U.S. Government Obligation or a specific payment of
                    principal of or interest on any such U.S. Government
                    Obligation held by such custodian for the account of the
                    holder of such depositary receipt, provided that (except
                    as required by law) such custodian is not authorized to
                    make any deduction from the amount payable to the holder
                    of such depositary receipt from any amount received by the
                    custodian in respect of the U.S. Government Obligation or
                    the specific payment of principal of or interest on the
                    U.S. Government Obligation evidenced by such depositary
                    receipt.

                (2) No Default or Event of Default with respect to Securities of
        the relevant series shall have occurred and be continuing on the date of
        such deposit or, insofar as subsections 501(9) and (10) are concerned,
        at any time during the period ending on the 91st day after the date of
        such deposit (it being understood that this condition shall not be
        deemed satisfied until the expiration of such period).

                (3) Such defeasance or covenant defeasance shall not cause the
        Trustee to have a conflicting interest as defined in Section 608 and for
        purposes of the Trust Indenture Act with respect to any securities of
        the Company.

                (4) Such defeasance or covenant defeasance shall not result in a
        breach or violation of, or constitute a default under, this Indenture or
        any other agreement or instrument to which the Company is a party or by
        which it is bound.

                (5) The Company shall have delivered to the Trustee an Officers'
        Certificate and an Opinion of Counsel, each stating that all conditions
        precedent provided for relating to either the defeasance under Section
        1202 or the covenant defeasance under Section 1203 (as the case may be)
        have been complied with.

                (6) In the case of an election under Section 1202, the Company
        shall have delivered to the Trustee an Opinion of Counsel stating that

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

                                (y) 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 shall confirm that, the Holders of the
                        Outstanding Securities or relevant series of Outstanding
                        Securities, as the




                                      -60-
<PAGE>   68
                    case may be, will not recognize income, gain or loss for
                    Federal income tax purposes as a result of such deposit,
                    defeasance and discharge 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 deposit,
                    defeasance and discharge had not occurred.

                (7) In the case of an election under Section 1203, the Company
        shall have delivered to the Trustee an Opinion of Counsel to the effect
        that the Holders of the Outstanding Securities or the relevant series of
        Outstanding Securities, as the case may be, will not recognize income,
        gain or loss for Federal income tax purposes as a result of such deposit
        and 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.

                (8) The Company shall have delivered to the Trustee an Opinion
        of Counsel to the effect that such deposit and defeasance or covenant
        defeasance shall not result in the trust arising from such deposit
        constituting an investment company as defined in the Investment Company
        Act of 1940, as amended, or such trust shall be qualified under such act
        or exempt from regulation thereunder.

SECTION 1205.   Deposited Money and U.S. Government Obligations to Be Held in
                Trust; Other Miscellaneous Provisions.

        Subject to the provisions of the last paragraph of Section 1003, all
money and U.S. Government Obligations (including the proceeds thereof) deposited
with the Trustee (or other qualifying trustee--collectively, for purposes of
this Section 1205, the "Trustee") pursuant to Section 1204 in respect of any
Securities shall be held in trust and applied by the Trustee, in accordance with
the provisions of such Securities and this Indenture, to the payment, either
directly or through any Paying Agent (including the Company acting as its own
Paying Agent) as the Trustee may determine, to the Holders of such Securities,
of all sums due and to become due thereon in respect of principal (and 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 U.S. Government Obligations
deposited pursuant to Section 1204 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 Securities.

        Anything in this Article Twelve to the contrary notwithstanding, the
Trustee shall deliver or pay to the Company from time to time upon Company
Request any money or U.S. Government Obligations held by it as provided in
Section 1204 with respect to any Securities which, in the opinion of a
nationally recognized accounting firm expressed in a written certification
thereof delivered to the Trustee, are in excess of the amount thereof which
would then be required to be deposited to effect an equivalent defeasance or
covenant defeasance, as the case may be, with respect to such Securities.






                                      -61-
<PAGE>   69

SECTION 1206.   Reinstatement.

        If the Trustee or the Paying Agent is unable to apply any money in
accordance with Section 1202 or 1203 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
Securities of relevant series shall be revived and reinstated as though no
deposit had occurred pursuant to this Article Twelve until such time as the
Trustee or Paying Agent is permitted to apply all such money in accordance with
Section 1202 and 1203; provided, however, that if the Company makes any payment
of principal of (and premium, if any) any Security following the reinstatement
of its obligations, the Company shall be subrogated to the rights of the Holders
of Securities of such series to receive such payment from the money held by the
Trustee or the Paying Agent.


                                      * * *

                          ----------------------------
        This instrument may be executed in any number of counterparts, each of
which so executed shall be deemed to be an original, but all such counterparts
shall together constitute but one and the same instrument.






                                      -62-
<PAGE>   70


        IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be
duly executed and attested, and the Trustee has caused its seal to be hereunto
affixed and attested, all as of the day and year first above written.

                                               XO Communications, Inc.

                                               By
                                                 -------------------------------
                                               Name:
                                                    ----------------------------
                                               Title:
                                                     ---------------------------

Attest:

------------------------------
Name:
     -------------------------
Title:
     -------------------------


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

                                               By
                                                 -------------------------------
                                               Name:
                                                    ----------------------------
                                               Title:
                                                     ---------------------------

Attest:

------------------------------
Name:
     -------------------------
Title:
     -------------------------







<PAGE>   71


STATE OF_____________________)
                             )      ss:
COUNTY OF____________________)



        On this ____ day of ______, 200__ before me personally appeared
________________, to me known, who, being duly sworn, did depose and say that
he/ she is the _______________ of XO Communications, Inc., one of the
corporations described in and which executed the foregoing instrument, and duly
acknowledged to me that he/ she executed the same by authority of the Board of
Directors of said corporation.

                                                  ------------------------------
                                                  Notary Public

                                                  COMMISSION EXPIRES



<PAGE>   72

STATE OF_____________________)
                             )      ss:
COUNTY OF____________________)


        On this ____ day of _______, 200__ before me personally appeared
______________, to me known, who, being duly sworn, did depose and say that he/
she is the _______________ of _________________________________, one of the
corporations described in and which executed the foregoing instrument, and duly
acknowledged to me that he/ she executed the same by authority of the Board of
Directors of said corporation.

                                                  ------------------------------
                                                  Notary Public

                                                  COMMISSION EXPIRES