<PAGE>   1
                           Nextel Communications, Inc.

                                       to

                          Harris Trust and Savings Bank
                                     Trustee



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


                                    Indenture

                          Dated as of November 4, 1998


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


                   12% Senior Serial Redeemable Notes due 2008






<PAGE>   2



                           Nextel Communications, Inc.

               Reconciliation and tie between Trust Indenture Act
               of 1939 and Indenture, dated as of November 4, 1998
<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
            (a)(5)                                             609
            (b)                                                608, 610
Section 311(a)                                                 613
            (b)                                                613
            (c)                                                613
Section 312(a)                                                 701, 702
            (b)                                                702(b)
            (c)                                                702(c)
Section 313(a)                                                 703
            (b)                                                703
            (c)                                                703
            (d)                                                703(b)
Section 314(a)(1)-(3)                                          704
            (a)(4)                                             1017
            (b)                                                Not Applicable
            (c)(1)                                             102, 401, 1204
            (c)(2)                                             102, 401, 1204
            (c)(3)                                             1204
            (d)                                                Not Applicable
            (e)                                                102
Section 315(a)                                                 601, 603
            (b)                                                602
            (c)                                                601
            (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



               INDENTURE, dated as of November 4, 1998, between Nextel
Communications, Inc., a Delaware corporation (herein called the "Company"),
having its principal office at 1505 Farm Credit Dr., McLean, Virginia 22102 and
Harris Trust and Savings Bank, an Illinois banking corporation, as Trustee
(herein called the "Trustee").

                             RECITALS OF THE COMPANY

               The Company has duly authorized the creation of an issue of its
Senior Serial Redeemable Notes due 2008 of substantially the tenor and amount
hereinafter set forth, and to provide therefor the Company has duly authorized
the execution and delivery of 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 covenanted and agreed, for the
equal and proportionate benefit of all Holders of the Securities, 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) whenever this Indenture requires that a particular ratio or
        amount be calculated with respect to a specified period after giving
        effect to certain transactions or events on a pro forma basis, such
        calculation will be made as if the transactions or events occurred on
        the first day of such period, unless otherwise specified herein, and all

<PAGE>   4


        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 at the date of such computation;

               (4) unless the context otherwise requires, any reference to an
        "Article" or a "Section" refers to an Article or Section, as the case
        may be, of this Indenture;

               (5) 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; and

               (6) each reference herein to a rule or form of the Commission
        shall mean such rule or form and any rule or form successor thereto, in
        each case as amended from time to time.

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

               Whenever this Indenture requires that a particular ratio or
amount be calculated with respect to a specified period after giving effect to
certain transactions or events on a pro forma basis, such calculation shall be
made as if the transactions or events occurred on the first day of such period,
unless otherwise specified.

               "Acquired Debt" means Debt of a Person existing at the time such
        Person becomes a Restricted Subsidiary or assumed by the Company or a
        Restricted Subsidiary in connection with the acquisition of assets from
        such Person.

               "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 Person. "Affiliate" shall be deemed to
        include, but only for purposes of Section 1011 and without limiting the
        application of the preceding sentence for the purpose of such or any
        other Section, any Person owning, directly or indirectly, (i) 10% or
        more of the Company's outstanding Common Stock or (ii) securities having
        10% or more of the total voting power of the Company's Voting Stock. 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. No
        individual shall be deemed 

<PAGE>   5


        to be controlled by or under common control with any specified Person
        solely by virtue of his or her status as an employee or officer of such
        specified Person or of any other Person controlled by or under common
        control with such specified Person.

               "Agent Members" has the meaning provided in Section 306(a).

               "Annualized Operating Cash Flow" means, for any fiscal quarter,
        the Operating Cash Flow for such fiscal quarter multiplied by four.

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

               "Average Life" means, at any date of determination with respect
        to any Debt, the quotient obtained by dividing (i) the sum of the
        products of (a) the number of years from such date of determination to
        the dates of each successive scheduled principal payment of such Debt
        and (b) the amount of such principal payment by (ii) the sum of all such
        principal payments.

               "Beneficial Owner" means a beneficial owner as defined in Rules
        13d-3 and 13d-5 under the Exchange Act (or any successor rules),
        including the provision of such Rules that a person shall be deemed to
        have beneficial ownership of all securities that such person has a right
        to acquire within 60 days, provided that a person shall not be deemed a
        beneficial owner of, or to own beneficially, any securities if such
        beneficial ownership (1) arises solely as a result of a revocable proxy
        delivered in response to a proxy or consent solicitation made pursuant
        to, and in accordance with, the Exchange Act and the applicable rules
        and regulations thereunder and (2) is not also then reportable on
        Schedule 13D (or any successor schedule) under the Exchange Act.

               "Board of Directors" means (i) whenever used in Sections 1009
        through 1015, inclusive, the board of directors of the Company and (ii)
        whenever used elsewhere herein, 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 (unless the context specifically
        requires that such resolution be adopted by a majority of the
        Disinterested Directors, in which case by a majority of such 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 are authorized or obligated
        by law or executive order to close.

               "Capital Lease Obligations" of any Person means the obligations
        to pay rent or other amounts under lease of (or other Debt arrangements
        conveying the right to use) real or personal property of such Person
        which are required to be classified and accounted for 

<PAGE>   6



        as a capital lease or a liability on the face of a balance sheet of such
        Person determined in accordance with generally accepted accounting
        principles and the amount of such obligations shall be the capitalized
        amount thereof in accordance with generally accepted accounting
        principles and the stated maturity thereof 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.

               "Capital Stock" of any Person means any and all shares,
        interests, participations or other equivalents (however designated) of
        stock of, or other ownership interests in, such Person.

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

                      (a) any person (as such term is used in Sections 13(d) and
               14(d) of the Exchange Act and the regulations thereunder) is or
               becomes the Beneficial Owner, directly or indirectly, of more
               than 50% of the total Voting Stock or Total Common Equity of the
               Company; provided that no Change of Control shall be deemed to
               occur pursuant to this clause (a) (x) if the person is a
               corporation with outstanding debt securities having a maturity at
               original issuance of at least one year and if such debt
               securities are rated Investment Grade by S&P or Moody's for a
               period of at least 90 consecutive days, beginning on the date of
               such event (which period will be extended up to 90 additional
               days for as long as the rating of such debt securities is under
               publicly announced consideration for possible downgrading by the
               applicable rating agency), or (y) if the person is a corporation
               (1) that is not, and does not have any outstanding debt
               securities that are, rated by S&P, Moody's or any other rating
               agency of national standing at any time during a period of 90
               consecutive days beginning on the date of such event (which
               period will be extended up to an additional 90 days for as long
               as any such rating agency has publicly announced that such
               corporation or debt thereof will be rated), unless after such
               date but during such period debt securities of such corporation
               having a maturity at original issuance of at least one year are
               rated Investment Grade by S&P or Moody's and remain so rated for
               the remainder of the period referred to in clause (x) above and
               (2) that, when determined as of the Trading Day immediately
               before and the Trading Day immediately after the date of such
               event, has Total Common Equity of at least $10 billion (provided
               that, solely for the purpose of calculating Total Common Equity
               as of such later Trading Day, the average Closing Price of the
               Common Stock of such person shall be deemed to equal the Closing
               Price of such Common Stock on such later Trading Day, subject to
               the last sentence of the definition of "Total Common Equity"); or

                       (b) the Company consolidates with, or merges with or
               into, another Person or sells, assigns, conveys, transfers,
               leases or otherwise disposes of all or substantially all of its
               assets to any Person, or any Person consolidates with, or merges
               with or into, the Company, in any such event pursuant to a
               transaction in which the outstanding Voting Stock of the Company
               is converted into or exchanged for cash, securities or other
               property, other than any such transaction where (i) the
               outstanding Voting Stock of the Company is converted into or
               exchanged for cash, securities or other property, other than any
               such transaction where (i) the outstanding Voting Stock of the
               Company is converted into or 
<PAGE>   7
                exchanged for (1) Voting Stock (other than Redeemable Stock) of
                the surviving or transferee Person or (2) cash, securities and
                other property in an amount which could be paid by the Company
                as a Restricted Payment under this Indenture and (ii)
                immediately after such transaction no person (as such term is
                used in Sections 13(d) and 14(d) of the Exchange Act and the
                regulations thereunder) is the Beneficial Owner, directly or
                indirectly, of more than 50% of the total Voting Stock or Total
                Common Equity of the surviving or transferee Person; provided
                that no Change of Control shall be deemed to occur pursuant to
                this clause (b), (x) if the surviving or transferee Person or
                the person referred to in clause (b)(ii) is a corporation with
                outstanding debt securities having a maturity at original
                issuance of at least one year and if such debt securities are
                rated Investment Grade by S&P or Moody's for a period of at
                least 90 consecutive days, beginning on the date of such event
                (which period will be extended up to 90 additional days for as
                long as the rating of such debt securities is under publicly
                announced consideration for possible downgrading by the
                applicable rating agency), or (y) if the surviving or transferee
                Person or such other person is a corporation (1) that is not,
                and does not have any outstanding debt securities that are,
                rated by S&P, Moody's or any other rating agency of national
                standing at any time during a period of 90 consecutive days
                beginning on the date of such event (which period will be
                extended up to an additional 90 days for as long as any such
                rating agency has publicly announced that such corporation or
                debt thereof will be rated), unless after such date but during
                such period debt securities of such corporation having a
                maturity at original issuance of at least one year are rated
                Investment Grade by S&P or Moody's and remain so rated for the
                remainder of the period referred to in clause (x) above and (2)
                that, when determined as of the Trading Day immediately before
                and the Trading Day immediately after the date of such event,
                has Total Common Equity of at least $10 billion (provided that,
                solely for the purpose of calculating Total Common Equity as of
                such later Trading Day, the average Closing Price of the Common
                Stock of such person shall be deemed to equal the Closing Price
                of such Common Stock on such later Trading Day, subject to the
                last sentence of the definition of "Total Common Equity"); or

                      (c) during any consecutive two-year period, individuals
               who at the beginning of such period constituted the Board of
               Directors (together with any directors who are members of the
               Board of Directors on the date hereof and any new directors whose
               election by such Board of Directors or whose nomination for
               election by the stockholders of the Company was approved by a
               vote of 66 2/3% of the directors 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.

               Any event that would constitute a Change of Control pursuant to
        clause (a) or (b) 



<PAGE>   8

        above (i) but for the proviso thereto shall not be deemed to be a Change
        of Control until such time (if any) as the conditions described in such
        proviso cease to have been met and (ii) if and to the extent resulting
        from any restructuring transaction or any sale or assignment of all or
        substantially all of the assets and liabilities of the Company to, or
        merger or consolidation of the Company with, any Person (any such
        transaction, a "Restructuring Transaction") effected at substantially
        the same time as and in connection with any of the Permitted
        Transactions described in clause (i) of the definition of the term
        "Permitted Transactions" shall not constitute a Change of Control so
        long as the Persons who, immediately prior to the closing of such
        Restructuring Transaction and the particular Permitted Transaction being
        consummated at substantially the same time and in connection therewith
        (the "Restructuring Closing"), were the Beneficial Owners, directly or
        indirectly, of more than 50% of the total Voting Stock and more than 50%
        of the Total Common Equity of the Company would remain, immediately
        after such Restructuring Closing (and after taking into account all
        issuances of securities in such Restructuring Transaction and related
        Permitted Transaction), the Beneficial Owners, directly or indirectly,
        of more than 50% of the total Voting Stock and more than 50% of the
        Total Common Equity of the Company (or the surviving transferee Person,
        as the case may be); provided that, immediately after any transaction or
        combination of transactions described in this clause (ii), no person (as
        such term is used in Sections 13(d) and 14(a) of the Exchange Act and
        the regulations thereunder) is the ultimate Beneficial Owner of more
        than 50% of the total Voting Stock or more than 50% of the Total Common
        Equity of the Company (or the surviving transferee Person, as the case
        may be) unless such person (as so defined) was the Beneficial Owner of
        more than 50% of the total Voting Stock and more than 50% of the Total
        Common Equity of the Company immediately before such transaction or
        combination of transactions.

                "Closing Date" means the date on which the Securities are
        originally issued hereunder.

                "Closing Price" on any Trading Day with respect to the per share
        price of any shares of Capital Stock means the last reported sale price
        regular way or, in case no such reported sale takes place on such day,
        the average of the reported closing bid and asked prices regular way, in
        either case on the New York Stock Exchange or, if such shares of Capital
        Stock are not listed or admitted to trading on such exchange, on the
        principal national securities exchange on which such shares are listed
        or admitted to trading or, if not listed or admitted to trading on any
        national securities exchange, on the Nasdaq Stock Market or, if such
        shares are not listed or admitted to trading on any national securities
        exchange or quoted on the Nasdaq Stock Market but the issuer is a
        Foreign Issuer (as defined in Rule 3b-4(b) under the Exchange Act) and
        the principal securities exchange on which such shares are listed or
        admitted to trading is a Designated Offshore Securities Market (as
        defined in Rule 902(a) under the Securities Act), the average of the
        reported closing bid and asked prices regular way on such principal
        exchange, or, if such shares are not listed or admitted to trading on
        any national securities exchange or quoted on the Nasdaq Stock Market
        and the issuer and principal securities exchange do not meet such
        requirements, the average of the closing bid and asked prices in the
        over-the-counter market as furnished by any New York Stock Exchange
        member firm of national standing 


<PAGE>   9

        that is selected from time to time by the Company for that purpose.

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

               "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 Stock" of any Person means Capital Stock of such Person
        that does not rank 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.

               "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 its Chairman of the Board,
        its President or a Vice President, and by its Treasurer, an Assistant
        Treasurer, its Secretary or an Assistant Secretary, and delivered to the
        Trustee.

               "Consolidated Adjusted Net Income" and "Consolidated Adjusted Net
        Loss" mean, for any period, the net income or net loss, as the case may
        be, of the Company and its Restricted Subsidiaries for such period, all
        as determined on a Consolidated basis in accordance with generally
        accepted accounting principles, adjusted, to the extent included in
        calculating such net income or net loss, as the case may be, by
        excluding without duplication (a) any after-tax gain or loss
        attributable to the sale, conversion or other disposition of assets
        other than in the ordinary course of business, (b) any after-tax gains
        resulting from the write-up of assets and any loss resulting from the
        write-down of assets, (c) any after-tax gain or loss on the repurchase
        or redemption of any securities (including in connection with the early
        retirement or defeasance of any Debt), (d) any foreign exchange gain or
        loss, (e) all payments in respect of dividends on shares of Preferred
        Capital Stock of the Company, (f) any other extraordinary, non-recurring
        or unusual items incurred by the Company or any of its Restricted
        Subsidiaries, (g) the net income (or loss) of any Person acquired by the
        Company or any Restricted Subsidiary in a pooling-of-interests
        transaction for any period prior to the date of such transaction and (h)
        all income or losses of Unrestricted Subsidiaries and Persons (other
        than Subsidiaries) accounted for by the Company using the equity method
        of accounting except, in the case of any such income, to the extent of
        dividends, interest or other cash distributions received directly or
        indirectly from any such Unrestricted Subsidiary or Person.
<PAGE>   10

                "Consolidated Adjusted Net Income (Loss)" means, for any period,
        the Company's Consolidated Adjusted Net Income or Consolidated Adjusted
        Net Loss for such period, as applicable.

                "Consolidated Debt to Annualized Operating Cash Flow Ratio"
        means, as at any date of determination, the ratio of (i) the aggregate
        amount of Debt of the Company and the Restricted Subsidiaries on a
        Consolidated basis outstanding as at the date of determination to (ii)
        the Annualized Operating Cash Flow of the Company for the most recently
        completed fiscal quarter of the Company.

                "Consolidated Interest Expense" of any Person means, for any
        period, the aggregate interest expense and fees and other financing
        costs in respect of Debt (including amortization of original issue
        discount and non-cash interest payments and accruals), the interest
        component in respect of Capital Lease Obligations and any deferred
        payment obligations of such Person and its Restricted Subsidiaries,
        determined on a Consolidated basis in accordance with generally accepted
        accounting principles and all commissions, discounts, other fees and
        charges owed with respect to letters of credit and bankers' acceptance
        financing and net costs (including amortizations of discounts)
        associated with interest rate swap and similar agreements and with
        foreign currency hedge, exchange and similar agreements and the amount
        of dividends paid in respect of Redeemable Stock.

                "Consolidated Net Income" and "Consolidated Net Loss" mean, for
        any period, the net income or net loss, as the case may be, of the
        Company and its Restricted Subsidiaries for such period, all as
        determined on a Consolidated basis in accordance with generally accepted
        accounting principles, adjusted, to the extent included in calculating
        such net income or net loss, as the case may be, by excluding without
        duplication (a) any after-tax gain or loss attributable to the sale,
        conversion or other disposition of assets other than in the ordinary
        course of business, (b) any after-tax gains resulting from the write-up
        of assets and any loss resulting from the write-down of assets, (c) any
        after-tax gain or loss on the repurchase or redemption of any securities
        (including in connection with the early retirement or defeasance of any
        Debt), (d) any foreign exchange gain or loss, (e) all payments in
        respect of dividends on shares of Preferred Capital Stock of the
        Company, (f) any other extraordinary, non-recurring or unusual items
        incurred by the Company or any of its Restricted Subsidiaries, (g) the
        net income (or loss) of any Person acquired by the Company or any
        Restricted Subsidiary in a pooling-of-interests transaction for any
        period prior to the date of such transaction, (h) all income or losses
        of Unrestricted Subsidiaries and Persons (other than Subsidiaries)
        accounted for by the Company using the equity method of accounting
        except, in the case of any such income, to the extent of dividends,
        interest or other cash distributions received directly or indirectly
        from any such Unrestricted Subsidiary or Person and (i) the net income
        (but not net loss) of any Restricted Subsidiary which is subject to
        restrictions which prevent the payment of dividends or the making of
        distributions to the Company but only to the extent of such
        restrictions.
<PAGE>   11

               "Consolidated Net Income (Loss)" means, for any period, the
        Company's Consolidated Net Income or Consolidated Net Loss for such
        period, as applicable.

               "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 Redeemable Stock of such Person; provided that,
        with respect to the Company, no effect shall be given to adjustments
        following the Closing Date 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.

               "Consolidation" means the consolidation of the accounts of each
        of the Restricted Subsidiaries with those of the Company, if and to the
        extent that the accounts of each such Restricted Subsidiary would
        normally be consolidated with those of the Company in accordance with
        generally accepted accounting principles; provided, however, that
        "Consolidation" shall not include consolidation of the accounts of any
        Unrestricted Subsidiary, but the interest of the Company or any
        Restricted Subsidiary in any Unrestricted Subsidiary shall be accounted
        for as an investment. The term "Consolidated" has a correlative meaning.

               "Corporate Trust Office" means the principal office of the
        Trustee at which at any particular time its corporate trust business
        shall be administered, which address as of the Closing Date is located
        at 311 West Monroe Street, 12th Floor, Chicago, Illinois 60606,
        Attention: Indenture Trust Division.

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

               "Covenant Defeasance" has the meaning specified in Section 1203.

               "Credit Facility" means any credit facility (whether a term or
        revolving type) of the type customarily entered into with banks, between
        the Company and/or any of its Restricted Subsidiaries, on the one hand,
        and any banks or other lenders, on the other hand (and any renewals,
        refundings, extensions or replacements of any such credit facility),
        which credit facility is designated by the Company as a "Credit
        Facility" for purposes of this Indenture, and shall include all such
        credit facilities in existence on the Closing Date whether or not so
        designated, to the extent that the aggregate principal balance of Debt
        that is Incurred and outstanding under all Credit Facilities at any time
        does not exceed $3 billion.

               "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 obligations
        Incurred in connection with the acquisition of property, assets or
        businesses, (iii) every reimbursement obligation of such Person with
        respect to letters of credit, bankers' 


<PAGE>   12

        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 (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) the
        maximum fixed redemption or repurchase price of Redeemable Stock of such
        Person at the time of determination plus accrued but unpaid dividends,
        (vii) every obligation of such Person under interest rate swap or
        similar agreements or foreign currency hedge, exchange or similar
        agreements of such Person, and (viii) every obligation of the type
        referred to in clauses (i) through (vii) of another Person and all
        dividends of another Person the payment of which, in either case, such
        Person has Guaranteed or is responsible or liable, directly or
        indirectly, as obligor, Guarantor or otherwise. The amount of Debt of
        any Person issued with original issue discount is the face amount of
        such Debt less the unamortized portion of the original issue discount of
        such Debt at the time of its issuance as determined in conformity with
        generally accepted accounting principles, and money borrowed at the time
        of the Incurrence of any Debt in order to pre-fund the payment of
        interest on such Debt shall be deemed not to be "Debt".

               "Default" means an event that is, or after notice or passage of
        time, or both, would be, an Event of Default.

               "Default Amount" has the meaning specified in Section 502.

               "Defaulted Interest" has the meaning specified in Section 309.

               "Defeasance" has the meaning specified in Section 1202.

               "Depository" shall mean The Depository Trust Company, as nominees
        and their respective successors.

               "Digital Mobile" means a radio communications system that employs
        digital technology with a multi-site configuration that will permit
        frequency reuse as described in the Memorandum.

               "Digital Mobile-SMR Operating Cash Flow" means, for any fiscal
        quarter, (i) the net income or loss, as the case may be, of the Company
        and its Restricted Subsidiaries from its Digital Mobile and Specialized
        Mobile Radio businesses and related activities and services for such
        fiscal quarter, plus (ii) depreciation and amortization charged with
        respect thereto for such fiscal quarter, all as determined on a
        Consolidated basis in accordance with generally accepted accounting
        principles, adjusted, to the extent included in calculating such net
        income or loss, by excluding (a) any after-tax gain or loss attributable
        to the sale, conversion or other disposition of assets other than in the
        ordinary course of business, (b) any gains resulting from the write-up
        of assets and any loss resulting from the write-down of assets, (c) any
        gain or loss on the repurchase or redemption of any securities
        (including in connection with the early retirement or defeasance of any
        Debt), (d) any foreign exchange gain or loss, (e) any other
<PAGE>   13

        extraordinary, non-recurring or unusual items and (f) all income or
        losses of Persons (other than Subsidiaries) accounted for by the Company
        using the equity method of accounting, except, in the case of any such
        income, to the extent of dividends, interest or other cash distributions
        received directly or indirectly from any such Person, plus (iii) all
        amounts deducted in calculating net income or loss for such fiscal
        quarter in respect of interest expense and other financing costs and all
        income taxes, whether or not deferred, applicable to such fiscal
        quarter, all as determined on a Consolidated basis in accordance with
        generally accepted accounting principles.

                "Directed Investment" by the Company or any of its Restricted
        Subsidiaries means any Investment for which the cash or property used
        for such Investment is received by the Company from the issuance and
        sale (other than to a Restricted Subsidiary) on or after June 1, 1997 of
        shares of its Capital Stock (other than Redeemable Stock), or any
        options, warrants or other rights to purchase such Capital Stock (other
        than Redeemable Stock) designated by the Board of Directors as a
        "Directed Investment" to be used for one or more specified investments
        in the telecommunications business (including related activities and
        services) and is so designated and used at any time within 365 days
        after the receipt thereof; provided that the aggregate amount of any
        such Directed Investments may not at any time exceed fifty percent (50%)
        of the aggregate amount of such cash or property received by the Company
        on or after June 1, 1997 from any such issuance and sale or capital
        contribution; and provided further that any proceeds from any such
        issuance or sale may not be used for such an Investment if such proceeds
        were, prior to being designated for use as a Directed Investment, (x)
        used to make a Restricted Payment or (y) used as the basis for the
        Incurrence of Debt under clause (i) of Section 1008 unless and until the
        amount of any such Debt (I) is treated as newly issued Debt and could be
        Incurred in accordance with Section 1008 (other than under clause (i)
        thereof) or (II) has been repaid or refinanced with the proceeds of Debt
        Incurred in accordance with Section 1008 (other than under clause (i)
        thereof) or (III) has otherwise been repaid and, in the circumstances
        described in clauses (I) and (II), the Company delivers to the Trustee a
        certificate confirming that the requirements of such clauses have been
        met.

                "Disinterested Director" means, with respect to any proposed
        transaction between the Company and an Affiliate thereof, a member of
        the Board of Directors who is not an officer or employee of the Company,
        would not be a party to, or have a financial interest in, such
        transaction and is not an officer, director or employee of, and does not
        have a financial interest in, such Affiliate. For purposes of this
        definition, no person would be deemed not to be a Disinterested Director
        solely because such person holds Capital Stock of the Company.

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

                "Exchange Securities" means any security of the Company
        containing terms identical to the Securities initially issued hereunder
        (except that such Securities shall have 


<PAGE>   14

        been registered under the Securities Act) that are issued and exchanged
        for the Securities pursuant to the Registration Rights Agreement.

                "Exchange Act" refers to the Securities Exchange Act of 1934 and
        any statute successor thereto, in each case as amended from time to
        time.

                "Expiration Date" has the meaning specified in the definition of
        Offer to Purchase.

                "Fair Market Value" means, for purposes of clause (i) of Section
        1008, the price that would be paid in an arm's-length transaction
        between an informed and willing seller under no compulsion to sell and
        an informed and willing buyer under no compulsion to buy, as determined
        in good faith by the Board of Directors, whose determination shall be
        conclusive if evidenced by a Board Resolution; provided that (x) the
        Fair Market Value of any security registered under the Exchange Act
        shall be the average of the closing prices, regular way, of such
        security for the 20 consecutive trading days immediately preceding the
        sale of Capital Stock and (y) in the event the aggregate Fair Market
        Value of any other property received by the Company exceeds $10 million,
        the Fair Market Value of such property shall be (i) so long as such a
        Fair Market Value determination of such property is required to be made
        pursuant to the Certificate of Designation for the Series D Preferred
        Stock, pursuant to the terms of the Series D Debenture Indenture,
        pursuant to the Certificate of Designation for the Series E Preferred
        Stock or pursuant to the terms of the Series E Debenture Indenture, the
        Fair Market Value as so determined, which shall be set forth in an
        Officer's Certificate delivered to the Trustee, and (ii) otherwise, such
        Fair Market Value shall be as determined in good faith by the Board of
        Directors, including a majority of Disinterested Directors who are then
        members of such Board of Directors, which determination shall be
        conclusive if evidenced by a Board Resolution.

                "FCC" means the Federal Communications Commission.

                "February Indenture" means the Indenture, dated February 11,
        1998, between the Company and Harris Trust and Savings Bank, Trustee,
        relating to the February Notes.

                "February Notes" means the Company's 9.95% Senior Serial
        Redeemable Discount Notes due 2008.

                "Global Securities" has the meaning provided in Section 201.

                "Guarantee" by any Person means any obligation, contingent or
        otherwise, of such Person guaranteeing any Debt of any other Person (the
        "primary obligor") in any manner, whether directly or indirectly, and
        including 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 


<PAGE>   15

        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.

                "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 (pursuant to a merger, consolidation, acquisition or
        other transaction), Guarantee or otherwise become liable in respect of
        such Debt or other obligation 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" and "Incurred", 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 Debt; provided further, however, that the accretion of original
        issue discount on Debt shall not be deemed to be an Incurrence of Debt.
        Debt otherwise Incurred by a Person before it becomes a Subsidiary of
        the Company shall be deemed to have been Incurred at the time it becomes
        such a 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.

                "Institutional Accredited Investor" means an institution that is
        an "accredited investor" as that term is defined in Rule 501(a)(1), (2),
        (3) or (7) under the Securities Act.

                "Interest Payment Date" means the Stated Maturity of an
        installment of interest on the Securities.

                "Investment" by any Person means any direct or indirect loan,
        advance or other extension of credit or capital contribution to (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), or
        purchase or acquisition of Capital Stock, bonds, notes, debentures or
        other securities or evidence of Debt issued by, any other Person or the
        designation of a Subsidiary as an Unrestricted Subsidiary; provided that
        a transaction will not be an Investment to the extent it involves (i)
        the issuance or sale by the Company of its Capital Stock (other than
        Redeemable Stock), including options, warrants or other rights to
        acquire such Capital Stock (other than Redeemable Stock) or (ii) a
        transfer, assignment or contribution by the Company of shares of Capital
        Stock (or any options, warrants or  

<PAGE>   16
        rights to acquire Capital Stock), or all or substantially all of the
        assets of, any Unrestricted Subsidiary of the Company to another
        Unrestricted Subsidiary of the Company.

               "Investment Grade" means a rating of at least BBB-, in the case
        of S&P, or Baa3, in the case of Moody's.

               "Licenses" means SMR licenses granted by the FCC that entitle the
        holder to use the radio channels covered thereby, subject to compliance
        with FCC rules and regulations, in connection with its SMR business.

               "Lien" means, with respect to any property or assets, any
        mortgage or deed of trust, pledge, hypothecation, assignment, deposit
        arrangement, security interest, lien, charge, easement, 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 any conditional sale or other title
        retention agreement having substantially the same economic effect as any
        of the foregoing).

               "Marketable Securities" means:

               (1) securities either issued directly or fully guaranteed or
        insured by the government of the United States of America or any agency
        or instrumentality thereof having maturities of not more than six
        months;

               (2) time deposits and certificates of deposit, having maturities
        of not more than six months from the date of deposit, of any domestic
        commercial bank having capital and surplus in excess of $500 million and
        having outstanding long-term debt rated A or better (or the equivalent
        thereof) by S&P or Aaa or better (or the equivalent thereof) by Moody's;
        and

               (3) commercial paper rated A-1 or the equivalent thereof by S&P
        or P-1 or the equivalent thereof by Moody's, and in each case maturing
        within six months.

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

               "Memorandum" means the offering memorandum dated October 28, 1998
        in connection with the offering of the Securities.

               "Moody's" means Moody's Investors Service, Inc. or, if Moody's
        Investors Service, Inc. shall cease rating debt securities having a
        maturity at original issuance of at 

<PAGE>   17

        least one year and such ratings business shall have been transferred to
        a successor Person, such successor Person; provided, however, that if
        Moody's Investors Service, Inc. ceases rating debt securities having a
        maturity at original issuance of at least one year and its ratings
        business with respect thereto shall not have been transferred to any
        successor Person, then "Moody's" shall mean any other national
        recognized rating agency (other than S&P) that rates debt securities
        having a maturity at original issuance of at least one year and that
        shall have been designated by the Company by a written notice given to
        the Trustee.

                "Non-U.S. Person" means a person who is not a "U.S. Person" (as
        defined in Regulation S).

                "Notice of Default" means a written notice of the kind specified
        in Section 501(5).

                "October Indenture" means the Indenture, dated October 22, 1997,
        between the Company and Harris Trust and Savings Bank, Trustee, relating
        to the October Notes.

                "October Notes" means the Company's 9 3/4% Senior Serial
        Redeemable Discount Notes due 2007.

                "Offer" has the meaning specified in the definition of Offer to
        Purchase.

                "Offer to Purchase" means a written offer (the "Offer") sent by
        the Company by first class mail, postage prepaid, to each Holder at his
        address appearing in the Security Register on the date of the Offer
        offering to purchase up to the principal amount of Securities 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 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, at a minimum, shall 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 required
        under applicable law, pro forma financial information concerning, among
        other things, the Offer to Purchase and the events requiring the Company
        to make the Offer to Purchase and 

<PAGE>   18

        (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 their Securities pursuant to
        the Offer to Purchase. The Offer shall also state:

                      (1) the section of this Indenture pursuant to which the
               Offer to Purchase is being made;

                      (2)  the Expiration Date and the Purchase Date;

                      (3) the aggregate principal amount at Stated Maturity of
               the Outstanding Securities offered to be purchased by the Company
               pursuant to the Offer to Purchase (the "Purchase Amount");

                      (4) the purchase price to be paid by the Company for each
               $1,000 principal amount at Stated Maturity of Securities accepted
               for payment (as specified pursuant to this Indenture) (the
               "Purchase Price");

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

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

                      (7) that interest, if any, on any Securities not tendered
               or tendered but not purchased by the Company pursuant to the
               Offer to Purchase will continue to accrue;

                      (8) 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;

                      (9) that each Holder electing to tender Securities
               pursuant to the Offer to Purchase will be required to surrender
               such Securities at the place or places specified in the Offer
               prior to the close of business on the Expiration Date (such
               Securities 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);

                      (10) that Holders will be entitled to withdraw all or any
               portion of the Securities tendered if the Company (or its Paying
               Agent) receives, not later than the close of business on the
               Expiration Date, a facsimile transmission or letter 


<PAGE>   19

                setting forth the name of the Holder, the principal amount at
                Stated Maturity of the Securities the Holder tendered, the
                certificate number of the Securities the Holder tendered and a
                statement that such Holder is withdrawing all or a portion of
                his tender;

                        (11) that the Company shall purchase all such Securities
                duly tendered and not withdrawn pursuant to the Offer to
                Purchase; and

                        (12) that in the case of any Holder whose Securities are
                purchased only in part, the Company shall execute, and the
                Trustee shall authenticate and deliver to the Holder of such
                Securities without service charge, new Securities of any
                authorized denomination as requested by such Holder, in an
                aggregate principal amount at Stated Maturity equal to and in
                exchange for the unpurchased portion of the aggregate principal
                amount at Stated Maturity of the Securities so tendered.

                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 the
        Chairman of the Board, the President or a Vice President, and by the
        Treasurer, an Assistant Treasurer, the Secretary or an Assistant
        Secretary, of the Company, and delivered to the Trustee. One of the
        officers signing an Officers' Certificate given pursuant to Section 1017
        shall be the principal executive, financial or accounting officer of the
        Company.

                "Offshore Global Securities" has the meaning provided in Section
        201.

                "Offshore Physical Securities" has the meaning provided in
        Section 201.

                "Operating Cash Flow" means, for any fiscal quarter, (i) the
        Company's Consolidated Adjusted Net Income (Loss) plus depreciation and
        amortization in respect thereof for such fiscal quarter, plus (ii) all
        amounts deducted in calculating Consolidated Adjusted Net Income (Loss)
        for such fiscal quarter in respect of interest expense and other
        financing costs, including dividends paid in respect of Redeemable
        Stock, and all income taxes, whether or not deferred, applicable to such
        income period, all as determined on a Consolidated basis in accordance
        with generally accepted accounting principles. For purposes of
        calculating Operating Cash Flow for the fiscal quarter most recently
        completed prior to any date on which an action is taken that requires a
        calculation of the Operating Cash Flow to Consolidated Interest Expense
        Ratio or Consolidated Debt to Annualized Operating Cash Flow Ratio, (1)
        any Person that is a Restricted Subsidiary on such date (or would become
        a Restricted Subsidiary in connection with the transaction that requires
        the determination of such ratio) will be deemed to have been a
        Restricted Subsidiary at all times during such fiscal quarter, (2) any
        Person that is not a Restricted Subsidiary on such date (or would cease
        to be a Restricted Subsidiary in connection with the transaction that
        requires the determination of such ratio) will be deemed not to have
        been a Restricted Subsidiary at any time during such fiscal quarter and
        (3) if the Company or any Restricted Subsidiary shall have in any 



<PAGE>   20

        manner acquired (including through commencement of activities
        constituting such operating business) or disposed (including through
        termination or discontinuance of activities constituting such operating
        business) of any operating business during or subsequent to the most
        recently completed fiscal quarter, such calculation will be made on a
        pro forma basis on the assumption that such acquisition or disposition
        had been completed on the first day of such completed fiscal quarter.

               "Operating Cash Flow to Consolidated Interest Expense Ratio"
        means, as at any date of determination, the ratio of (i) the Operating
        Cash Flow of the Company for the most recently completed fiscal quarter
        of the Company to (ii) the Consolidated Interest Expense of the Company
        and its Restricted Subsidiaries for the most recently completed fiscal
        quarter of the Company.

               "Opinion of Counsel" means a written opinion of counsel, who may
        be counsel for the Company, and who shall be acceptable to the Trustee.

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

                        (i) Securities theretofore canceled 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;

                        (iii) Securities which have been paid pursuant to
                Section 308 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 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; and

                        (iv) Securities as to which Defeasance has been effected
                pursuant to Section 1202;

        provided, however, that in determining whether the Holders of the
        requisite principal amount of the Outstanding Securities have given,
        made or taken any request, demand, 

<PAGE>   21

        authorization, direction, notice, consent, waiver or other action
        hereunder as of any date, 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 in
        relying upon any such request, demand, authorization, direction, notice,
        consent, waiver or other action, only Securities which the Trustee knows
        to be so owned shall be so disregarded. Securities 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 or any Affiliate of the
        Company or of such other obligor.

               "pari passu", when used with respect to the ranking of any Debt
        of any Person in relation to other Debt of such Person, means that each
        such Debt (a) either (i) is not subordinated in right of payment to any
        other Debt of such Person or (ii) is subordinate in right of payment to
        the same Debt of such Person as is the other and is so subordinate to
        the same extent and (b) is not subordinate in right of payment to the
        other or to any Debt of such Person as to which the other is not so
        subordinate.

               "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.

               "Permitted Debt" means:

                      (i) any Debt (including Guarantees thereof) outstanding on
               the Closing Date (including the Securities) and any accretion of
               original issue discount and accrual of interest with respect to
               such Debt;

                      (ii) any Debt outstanding under a Credit Facility;

                      (iii) any Vendor Financing Debt or any other Debt Incurred
               to finance the cost (including the cost of design, development,
               construction, improvement, installation or integration) of
               equipment, inventory or network assets acquired by the Company or
               any of its Restricted Subsidiaries after the Closing Date;

                      (iv) Debt (A) to the Company or (B) to any Restricted
               Subsidiary; provided that any event which results in any such
               Restricted Subsidiary ceasing to be a Restricted Subsidiary or
               any subsequent transfer of such Debt (other than to the Company
               or another Restricted Subsidiary) shall be deemed, in each case,
               to constitute an Incurrence of such Debt not permitted by this
               clause (iv);

                      (v) Debt (A) in respect of performance, surety or appeal
               bonds provided in the ordinary course of business, (B) under
               foreign currency hedge, interest rate swap or similar agreements;
               provided that such agreements (a) are designed solely to protect
               the Company or its Restricted Subsidiaries against fluctuations
               in foreign currency exchange rates or interest rates and (b) do
               not increase the Debt of the obligor outstanding at any time
               other than as a result of fluctuations in 

<PAGE>   22

                foreign currency exchange rates or interest rates or by reason
                of fees, indemnities and compensation payable thereunder; and
                (C) arising from agreements providing for indemnification,
                adjustment of purchase price or similar obligations, or from
                Guarantees or letters of credit, surety bonds or performance
                bonds securing any obligations of the Company or any Restricted
                Subsidiary pursuant to such agreements, in any case Incurred in
                connection with the disposition of any business, assets or
                Restricted Subsidiary (other than Guarantees of Debt Incurred by
                any Person acquiring all or any portion of such business, assets
                or Restricted Subsidiary for the purpose of financing such
                acquisition), in a principal amount not to exceed the gross
                proceeds actually received by the Company or any Restricted
                Subsidiary in connection with such disposition;

                        (vi) renewals, refundings or extensions of any Debt
                referred to in clause (i) or (iii) above or Incurred pursuant to
                clause (ii) of Section 1008 and any renewals, refundings or
                extensions thereof, plus (A) the amount of any premium
                reasonably determined by the Company as necessary to accomplish
                such renewal, refunding or extension and (B) such other fees and
                expenses of the Company reasonably incurred in connection with
                the renewal, refunding or extension, provided that such renewal,
                refunding or extension shall constitute Permitted Debt only (a)
                to the extent that it does not result in an increase in the
                aggregate principal amount (or, if such Debt provides for an
                amount less than the principal amount thereof to be due and
                payable upon a declaration of acceleration of the maturity
                thereof, in an amount not greater than such lesser amount) of
                such Debt (except as permitted by clause (A) or (B) above), and
                (b) to the extent such renewed, refunded or extended Debt does
                not have a mandatory redemption date prior to the mandatory
                redemption date of the Debt being renewed, refunded or extended
                or have an Average Life shorter than the remaining Average Life
                of the Debt being renewed, refunded or extended;

                        (vii) Debt payable solely in, or mandatorily convertible
                into, Capital Stock (other than Redeemable Stock) of the
                Company; and

                        (viii) Debt (in addition to Debt permitted under clauses
                (i) through (vii) above) in an aggregate principal amount
                outstanding at any time not to exceed $450 million.

                "Permitted Distribution" of a Person means (x) the exchange by
        such Person of Capital Stock (other than Redeemable Stock) for
        outstanding Capital Stock; (y) the redemption, repurchase, defeasance or
        other acquisition or retirement for value of Debt of the Company that is
        subordinate in right of payment to the Securities, in exchange for
        (including any such exchange pursuant to the exercise of a conversion
        right or privilege in connection with which cash is paid in lieu of the
        issuance of fractional shares or scrip), or out of the proceeds of a
        substantially concurrent issue and sale (other than to a Restricted
        Subsidiary) of, either (a) Capital Stock of the Company (other than
        Redeemable Stock) or (b) Debt of the Company that is subordinate in
        right of payment to the Securities on subordination terms no less
        favorable to the Holders of the Securities in 

<PAGE>   23

        their capacities as such than the subordination terms (or other
        arrangement) applicable to the Debt that is redeemed, repurchased,
        defeased or otherwise acquired or retired for value, provided that, in
        the case of this clause (b), such new Debt does not mature prior to the
        Stated Maturity or have a mandatory redemption date prior to the
        mandatory redemption date of the Debt being redeemed, repurchased,
        defeased or otherwise acquired or retired for value or have an Average
        Life shorter than the remaining Average Life of the Debt being redeemed,
        repurchased, defeased or otherwise acquired or retired for value; and
        (z) dividend, penalty or other mandated payments, including mandatory
        repurchases, on or in respect of any class or series of the Company's
        Preferred Capital Stock that is authorized and designated on the Closing
        Date (i.e., the Class A Preferred Stock, Class B Preferred Stock, Class
        C Preferred Stock, Series D Preferred Stock and Series E Preferred Stock
        of the Company).

                "Permitted Investment" means any Investment in Marketable
        Securities.

                "Permitted Transaction" means (i) any transaction pursuant to
        agreements (whether or not definitive, and regardless of whether binding
        or non-binding) existing on the Closing Date and described in or
        incorporated by reference into the Memorandum and (ii) any transaction
        or transactions with any vendor or vendors of property or materials used
        in the telecommunications business (including related activities and
        services) of the Company or any Restricted Subsidiary, provided (x) such
        transactions are in the ordinary course of business and (y) such vendor
        does not beneficially own more than 50% of the voting power of the
        Voting Stock of the Company.

                "Person" means any individual, corporation, partnership, joint
        venture, trust, unincorporated organization or government or any agency
        or political subdivision thereof.

               "Predecessor Security" of any particular Security means every
        previous Security 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 308
        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 Capital Stock" as applied to the Capital 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.

               "Private Placement Legend" means the legend initially set forth
        on the Securities in the form set forth in Section 205.
<PAGE>   24

                "Purchase Amount" has the meaning specified in the definition of
        Offer to Purchase.

                "Purchase Date" has the meaning specified in the definition of
        Offer to Purchase.

                "Purchase Price" has the meaning specified in the definition of
        Offer to Purchase.

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

                "Record Expiration Date" has the meaning specified in Section
        104.

                "Redeemable Stock" of any Person means any Capital Stock of such
        Person that by its terms or otherwise is (i) required to be redeemed
        prior to the Stated Maturity of the Securities, (ii) redeemable at the
        option of the holder thereof at any time prior to the Stated Maturity of
        the Securities or (iii) convertible into or exchangeable for Capital
        Stock referred to in clause (i) or (ii) above or Debt having a scheduled
        maturity prior to the Stated Maturity of the Securities; provided that
        any Capital Stock that would not constitute Redeemable Stock but for
        provisions thereof giving holders thereof the right to require such
        Person to repurchase or redeem such Capital Stock upon the occurrence of
        a "change of control" occurring prior to the Stated Maturity of the
        Securities shall not constitute Redeemable Stock if the "change of
        control" provisions applicable to such Capital Stock are no more
        favorable to the holders of such Capital Stock than the provisions
        contained in Section 1013 and such Capital Stock specifically provides
        that such Person will not repurchase or redeem any such stock pursuant
        to such provision prior to the Company's repurchase of such Securities
        as are required to be repurchased pursuant to Section 1013; and further
        provided that the Series D Preferred Stock and the Series E Preferred
        Stock shall not be considered to constitute Redeemable Stock.

                "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.

                "Registration Rights Agreement" means the Registration Rights
        Agreement dated the Closing Date, between the Company and Morgan Stanley
        & Co. Incorporated.

                "Registration Statement" means the Registration Statement as
        defined and described in the Registration Rights Agreement.

                "Regular Record Date" for the interest payable on any Interest
        Payment Date means the April 15 or October 15 (whether or not a Business
        Day), as the case may be, next preceding such Interest Payment Date.

                "Regulation S" means Regulation S under the Securities Act.
<PAGE>   25

               "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
        the Securities for any action 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, any past default
        and its consequences, and (ii) with respect to all other actions
        requiring the consent of holders of the Securities, the consent of
        either (x) a majority in aggregate principal amount at Stated Maturity
        of the Securities or (y) a majority in aggregate principal amount at
        Stated Maturity of (I) the Securities, (II) the September Notes, if the
        holders of the September Notes are being requested to consent to such
        action with respect to the terms of the September Notes or the September
        Indenture, (III) the October Notes, if the holders of the October Notes
        are being requested to consent to such action with respect to the terms
        of the October Notes or the October Indenture, (IV) the February Notes,
        if the holders of the February Notes are being requested to consent to
        such action with respect to the terms of the February Notes or the
        February Indenture and (V) any other issue of unsubordinated, unsecured
        notes issued by the Company, if such notes or the indenture pursuant to
        which such notes were issued both (A) require the consent of the holders
        of such notes to such action and (B) provide that the holders thereof
        will vote with the holders of the Securities with respect to such
        action.

               "Restricted Payments" has the meaning specified in Section 1009.

               "Restricted Subsidiary" means any Subsidiary of the Company,
        whether existing on the Closing Date or created subsequent thereto,
        designated from time to time by the Board of Directors as (or otherwise
        deemed to be) a "Restricted Subsidiary" in accordance with Section 1010.

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

               "S&P" means Standard & Poor's Ratings Services or, if Standard &
        Poor's Ratings Services shall cease rating debt securities having a
        maturity at original issuance of at least one year and such ratings
        business shall have been transferred to a successor Person, such
        successor Person; provided, however, that if Standard & Poor's Ratings
        Services ceases rating debt securities having a maturity at original
        issuance of at least one year and its ratings business with respect
        thereto shall not have been transferred to any successor Person, then
        "S&P" shall mean any other nationally recognized rating agency (other
        than Moody's) that rates debt securities having a maturity at original
        issuance of at least one year and that shall have been designated by the
        Company by a written notice given to the Trustee.

               "Securities" means securities designated in the first paragraph
        of the RECITALS OF THE COMPANY that are authenticated and delivered
        under this Indenture. For all purposes of this Indenture, the term
        "Securities" shall include the Securities issued on the Closing Date,
        any Exchange Securities to be issued and exchanged for any Securities

<PAGE>   26

        pursuant to the Registration Rights Agreement and any other Securities
        issued after the Closing Date under this Indenture. For purposes of this
        Indenture all Securities shall vote together as one series of Securities
        under this Indenture.

               "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.

               "September Indenture" means the Indenture, dated September 17,
        1997, between the Company and Harris Trust and Savings Bank, Trustee,
        relating to the September Notes.

               "September Notes" means the Company's 10.65% Senior Redeemable 
        Discount Notes due 2007.

               "Series D Debenture Indenture" means an indenture (having terms
        and conditions substantially as summarized in that certain confidential
        Offering Memorandum, dated July 16, 1997), prepared in connection with
        the original issuance by the Company of shares of Series D Preferred
        Stock, pursuant to which certain exchange debentures may be issued by
        the Company in exchange for outstanding shares of Series D Preferred
        Stock.

             "Series D Preferred Stock" means the 13% Series D Exchangeable
        Redeemable Preferred Stock of the Company issued on July 21, 1997 and
        any shares of Preferred Capital Stock issued in exchange therefor or as
        payment in kind dividends thereon.

               "Series E Debenture Indenture" means an indenture (having terms
        and conditions substantially as summarized in that certain confidential
        Offering Memorandum, dated February 6, 1998), prepared in connection
        with the original issuance by the Company of shares of Series E
        Preferred Stock, pursuant to which certain exchange debentures may be
        issued by the Company in exchange for outstanding shares of Series E
        Preferred Stock.

               "Series E Preferred Stock" means the 11.125% Series E
        Exchangeable Redeemable Preferred Stock of the Company issued on
        February 11, 1998 and any shares of Preferred Capital Stock issued in
        exchange therefor or as payment in kind dividends thereon.

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

               "Special Record Date" for the payment of any Defaulted Interest
        means a date 

<PAGE>   27

        fixed by the Trustee pursuant to Section 309.

               "Specialized Mobile Radio" or "SMR" means a mobile radio
        communications system that is operated as described in the Memorandum.

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

               "Subsidiary" of any Person means (i) a corporation more than 50%
        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.

               "Total Common Equity" of any Person means, as of any day of
        determination (and as modified for purposes of the definition of "Change
        of Control"), the product of (i) the aggregate number of outstanding
        primary shares of Common Stock of such Person on such day (which shall
        not include any options or warrants on, or securities convertible or
        exchangeable into, shares of Common Stock of such Person) and (ii) the
        average Closing Price of such Common Stock over the 20 consecutive
        Trading Days immediately preceding such day. If no such Closing Price
        exists with respect to shares of any such class, the value of such
        shares for purposes of clause (ii) of the preceding sentence shall
        be determined by the Board of Directors in good faith and evidenced by a
        Board Resolution.

               "Total Market Value of Equity" of the Company means, as of any
        day of determination, the sum of (1) the product of (i) the aggregate
        number of outstanding primary shares of Common Stock of the Company on
        such day (which shall not include any options or warrants on, or
        securities convertible or exchangeable into, shares of Common Stock of
        the Company) and (ii) the average Closing Price of such Common Stock
        over the 20 consecutive Trading Days immediately preceding such day,
        plus (2) the liquidation value of any outstanding shares of Preferred
        Capital Stock of the Company on such day. If no such Closing Price
        exists with respect to shares of any such class, the value of such
        shares for purposes of clause (ii) of the preceding sentence shall be
        determined by the Board of Directors in good faith and evidenced by a
        Board Resolution.

               "Trading Day" with respect to a securities exchange or automated
        quotation system means a day on which such exchange or system is open
        for a full day of trading.

               "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 such successor Trustee.
<PAGE>   28

               "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.

               "U.S. Global Securities" has the meaning provided in Section 201.

               "U.S. Government Obligation" has the meaning specified in Section
        1204.

               "U.S. Physical Securities" has the meaning provided in Section 
        201.

               "Unrestricted Subsidiary" means Unrestricted Subsidiary Funding
        Company and any other Subsidiary that is not a Restricted Subsidiary and
        includes any Restricted Subsidiary that becomes an Unrestricted
        Subsidiary in accordance with Section 1010.

               "Vendor Financing Debt" means any Debt owed to (i) a vendor or
        supplier of any property or materials used by the Company or its
        Restricted Subsidiaries in their telecommunications business, (ii) any
        Affiliate of such a vendor or supplier, (iii) any assignee of such a
        vendor, supplier or Affiliate of such a vendor or supplier, or (iv) a
        bank or other financial institution that has financed or refinanced the
        purchase of such property or materials from such a vendor, supplier,
        Affiliate of such a vendor or supplier or assignee of such a vendor or
        supplier; provided that the aggregate amount of such Debt does not
        exceed the sum of (w) the purchase price of such property or materials
        (including transportation, installation, warranty and testing charges,
        as well as applicable taxes paid, in respect of such property or
        materials), (x) the cost of design, development, site acquisition and
        construction, (y) any interest or other financing costs accruing or
        otherwise payable in respect of the foregoing, and (z) the cost of any
        services provided by such vendor, supplier or Affiliate of such vendor
        or supplier.

               "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 the Company means a
        Restricted Subsidiary all of the outstanding Capital Stock of which
        (other than directors' qualifying shares) shall at the time be owned by
        the Company or by one or more Wholly Owned Restricted Subsidiaries or by
        the Company and one or more Wholly Owned Restricted Subsidiaries.
<PAGE>   29


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 opinions as may be required under the Trust
Indenture Act. 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 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 

<PAGE>   30

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.


SECTION 104.  Acts of Holders; Record Dates.

               Any request, demand, authorization, direction, notice, consent,
waiver or other action provided or permitted 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 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 entitled to give or take any
request, demand, authorization, direction, notice, consent, waiver or other
action provided or permitted by this Indenture to be given or taken by Holders
of Securities, 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 any record date is set 

<PAGE>   31

pursuant to this paragraph, the Holders of Outstanding Securities 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 Record Expiration Date by Holders of the requisite principal amount
of Outstanding Securities on such record date; and provided, further, that for
the purpose of determining whether Holders of the requisite principal amount of
such Securities have taken such action, no Security shall be deemed to have been
Outstanding on such record date unless it is also Outstanding on the date such
action is to become effective. Nothing in this paragraph shall 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 canceled
and of no effect), nor shall anything in this paragraph be construed to render
ineffective any action taken by Holders of the requisite principal amount of
Outstanding Securities 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 Record Expiration Date to be given to the Trustee in writing and to
each Holder of Securities 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 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), (iv) any direction referred to in Section 512 or (v) the
Required Consent. If any record date is set pursuant to this paragraph, the
Holders of Outstanding Securities 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 Record Expiration Date by Holders of the requisite principal amount
of Outstanding Securities on such record date; and provided, further, that for
the purpose of determining whether Holders of the requisite principal amount of
such Securities have taken such action, no Security shall be deemed to have been
Outstanding on such record date unless it is also Outstanding on the date such
action is to become effective. Nothing in this paragraph shall be construed to
prevent the Trustee from setting a new record date for any action (whereupon the
record date previously set shall automatically and without any action by any
Person be canceled and of no effect), nor shall anything in this paragraph be
construed to render ineffective any action taken by Holders of the requisite
principal amount of Outstanding Securities 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 matter(s)
to be submitted for potential action by Holders and the applicable Record
Expiration Date to be given to the Company in writing and to each Holder of
Securities in the manner set forth in Section 106.

               With respect to any record date set pursuant to this Section, the
party hereto that sets such record date may designate any day as the "Record
Expiration Date" and from time to time may change the Record Expiration Date to
any earlier or later day, provided that no such change shall be effective unless
notice of the proposed new Record Expiration Date is given to the other party
hereto in writing, and to each Holder of Securities in the manner set forth in
Section 106, on or before the existing Record Expiration Date. If a Record
Expiration Date is 

<PAGE>   32

not designated with respect to any record date set pursuant to this Section, the
party hereto that set such record date shall be deemed to have initially
designated the 180th day after such record date as the Record Expiration Date
with respect thereto, subject to its right to change the Record Expiration Date
as provided in this paragraph. Notwithstanding the foregoing, no Record
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 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 made, given, furnished or
        filed in writing and mailed, first-class postage prepaid, to or with the
        Trustee at its Corporate Trust Office, Attention: Indenture Trust
        Division, 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 it 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 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 

<PAGE>   33

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 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.


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 

<PAGE>   34

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 (including with respect to the accrual of interest) as if
made on the Interest Payment Date, Redemption Date or Purchase Date, or at the
Stated Maturity.


SECTION 114.  No Recourse Against Others.

               No recourse for the payment of the principal of, premium, if any,
or interest on any of the Securities, or for any claim based thereon or
otherwise in respect thereof, and no recourse under or upon any obligation,
covenant or agreement of the Company contained in this Indenture, or in any of
the Securities, or because of the creation of any indebtedness represented
thereby, shall be had against any incorporator or against any past, present or
future partner, shareholder, other equity holder, officer, director, employee or
controlling person, as such, of the Company or of any successor Person, either
directly or through the Company or any successor Person, whether by virtue of
any constitution, statute or rule of law, or by the enforcement of any
assessment or penalty or otherwise; it being expressly understood that all such
liability is hereby expressly waived and released as a condition of, and as a
consideration for, the execution of this Indenture and the issue of the
Securities.


                                   ARTICLE TWO

                                 Security Forms

SECTION 201.  Forms Generally.

               The Securities and the Trustee's certificates of authentication
shall be in substantially the forms set forth in this Article, with such
appropriate 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
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 thereof.

               Securities offered and sold in reliance on Rule 144A shall be
issued initially in the form of one or more permanent global Securities in
registered form, substantially in the form set forth in Section 202 (the "U.S.
Global Securities"), deposited with the Trustee, as custodian for the
Depository, duly executed by the Company and authenticated by the Trustee as
hereinafter 

<PAGE>   35

provided. The aggregate principal amount of the Global Securities may from time
to time be increased or decreased by adjustments made on the records of the
Trustee as custodian for the Depository or its nominee, as hereinafter provided

               Securities offered and sold in offshore transactions in reliance
on Regulation S shall be issued initially in the form of one or more permanent
Global Securities in registered form substantially in the form set forth in
Section 202 (the "Offshore Global Securities") deposited with the Trustee, as
custodian for the Depositary, duly executed by the Company and authenticated by
the Trustee as hereinafter provided. The aggregate principal amount of the
Offshore Global Securities may from time to time be increased or decreased by
adjustments made on the records of the Trustee, as custodian for the Depositary,
as hereinafter provided. The U.S. Global Securities and the Offshore Global
Securities are sometimes collectively herein referred to as the "Global
Securities."

               Securities offered and sold in reliance on Regulation D under the
Securities Act or Securities issued pursuant to Section 307(b) shall be issued
in the form of permanent certificated Securities in registered form
substantially in the form set forth in Section 202 (the "U.S. Physical
Securities"). Securities issued pursuant to Section 307(d) in exchange for
interests in the Global Securities shall be in the form of permanent
certificated Securities in registered form substantially in the form set forth
in Section 202 (the "Offshore Physical Securities"). The Offshore Physical
Securities and U.S. Physical Securities are sometimes collectively herein
referred to as the "Physical 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 permitted by the rules of any
securities exchange on which the Securities may be listed, all as determined by
the officers executing such Securities, as evidenced by their execution of such
Securities.


SECTION 202.  Form of Face of Security.

                           Nextel Communications, Inc.
                   12% Senior Serial Redeemable Notes due 2008


                                                        No. __________$________
                                                              CUSIP NO.________
                                                               CINS NO.________


               Nextel Communications, Inc., a corporation duly organized and
existing under the laws of the State of Delaware (herein called the "Company",
which term includes any successor 

<PAGE>   36

Person under the Indenture hereinafter referred to), for value received, hereby
promises to pay to __________________, or registered assigns, the principal sum
of _____________________ Dollars on November 1, 2008 and to pay cash interest
thereon from November 4, 1998 or from the most recent Interest Payment Date to
which interest has been paid or duly provided for, semi-annually in arrears on
May 1 and November 1 in each year, commencing May 1, 1999 at the rate of 12% per
annum, until the principal hereof is paid or duly provided for, provided that
any principal and premium, and any such installment of interest, which is
overdue shall bear interest at the rate of 12 % per annum (to the extent that
the payment of such interest shall be legally enforceable), from the dates such
amounts are due until they are paid or duly provided for, and such interest
shall be payable on demand. The interest so payable, and punctually paid or duly
provided for, on any Interest Payment Date will, as provided in such Indenture,
be paid to the Person in whose name this Security (or one or more Predecessor
Securities) is registered at the close of business on the Regular Record Date
for such interest, which shall be the April 15 or October 15 (whether or not a
Business Day), as the case may be, next preceding such Interest Payment Date.
Any such interest not so punctually paid or duly provided for will forthwith
cease to be payable to the Holder on such Regular Record Date and may either be
paid to the Person in whose name this Security (or one or more Predecessor
Securities) is registered at the close of business on a Special Record Date for
the payment of such Defaulted Interest to be fixed by the Trustee, notice
whereof shall be given to Holders of Securities not less than 10 days prior to
such Special Record Date, or be paid at any time in any other lawful manner not
inconsistent with the requirements of any securities exchange on which the
Securities may be listed, and upon such notice as may be required by such
exchange, all as more fully provided in said Indenture.

               In the case of a default in payment of principal upon
acceleration, redemption or repurchase, the overdue principal and any overdue
premium shall bear interest at the rate of 12% per annum (to the extent that the
payment of such interest shall be legally enforceable), from the dates such
amounts are due until they are paid or duly provided for. Interest on any
overdue principal or premium shall be payable on demand. Any such interest on
overdue principal or premium which is not paid on demand shall bear interest at
the rate of 12% per annum (to the extent that the payment of such interest on
interest shall be legally enforceable), from the date of such demand until the
amount so demanded is paid or duly provided for, and such shall be payable on
demand.

               If an exchange offer registered under the Securities Act is not
consummated on or before June 1, 1999 in accordance with the terms of the
Registration Rights Agreement, incremental interest (in addition to the interest
otherwise due on the Securities after such date) will accrue from June 1, 1999,
at an annual rate of 0.5% of the principal amount of the Securities, and if such
exchange offer is not consummated on or before September 1, 1999, additional
incremental interest will accrue from September 1, 1999 at an annual rate of
0.5% of the principal amount of the Securities, with such incremental interest
payable in cash semi-annually, in arrears, on each May 1 and November 1,
commencing November 1, 1999, until the earlier of the date upon which (i) the
exchange offer is consummated, (ii) a Shelf Registration Statement with respect
to all Registrable Securities (as defined in the Registration Rights Agreement)
is declared effective, or (iii) the Securities become fully tradeable without
registration under the Securities Act, provided that from and after any such
relevant date, no such incremental interest will accrue on the Securities and
the interest rate on the Securities shall return to the original rate 

<PAGE>   37

of 12% per annum and shall accrue at such original rate thereafter; and provided
further that upon the request of any Holder of the Securities, the Company will
deliver to such Holder certificates evidencing such Holder's Securities without
the Private Placement Legend. The Holder of this Security is entitled to the
benefits of such Registration Rights Agreement.

               Payment of the principal of (and premium, if any) and any
interest on this Security will be made at the office or agency of the Company
maintained for that purpose in the Borough of Manhattan, The City of New York,
in such coin or currency of the United States of America as at the time of
payment is legal tender for payment of public and private debts; provided,
however, that at the option of the Company payment of interest may be made by
check mailed to the address of the Person entitled thereto as such address shall
appear in the Security Register.

               Reference is hereby made to the further provisions of this
Security set forth on the reverse hereof, which further provisions shall for all
purposes have the same effect as if set forth at this place.

               Unless the certificate of authentication hereon has been executed
by the Trustee referred to on the reverse hereof by manual signature, this
Security shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.

               IN WITNESS WHEREOF, the Company has caused this instrument to be
duly executed under its corporate seal.


                                            NEXTEL COMMUNICATIONS, INC.
[Seal]

                                            By:
                                               ---------------------------------
                                               Title:
Attest:

------------------------------
Title:


SECTION 203.  Form of Reverse of Security.

               This Security is one of a duly authorized issue of Securities of
the Company designated as its 12% Senior Serial Redeemable Notes due 2008
(herein called the "Securities"), limited in aggregate principal amount to
$300,000,000, issued and to be issued under an Indenture, dated as of November
4, 1998 (herein called the "Indenture", which term shall have the meaning
assigned to it in such instrument), between the Company and Harris Trust and
Savings Bank, as Trustee (herein called the "Trustee", which term includes any
successor trustee under the Indenture), and reference is hereby made to the
Indenture for a statement of the respective rights, limitations of rights,
duties and immunities thereunder of the Company, the 

<PAGE>   38

Trustee and the Holders of the Securities and of the terms upon which the
Securities are, and are to be, authenticated and delivered.

               The Securities may be redeemed at any time on or after November
1, 2003, at the Company's option, in whole or in part, upon not less than 30 nor
more than 60 days' prior written notice mailed by first class mail to each
holder's last address as it appears in the Security Register, at the Redemption
Prices (expressed as a percentage of the principal amount thereof) set forth
below, plus an amount in cash equal to all accrued and unpaid interest, if any,
to the Redemption Date, if redeemed during the 12-month period beginning
November 1 of each of the years set forth below.
<TABLE>
<CAPTION>

                   YEAR                           PERCENTAGE
                   ----                           ----------
<S>                                               <C>
                   2003                            106.000%
                   2004                            104.800%
                   2005                            103.600%
                   2006                            102.400%
                   2007                            101.200%
                   2008                            100.000%
</TABLE>

               Interest installments whose Stated Maturity is on or prior to any
Redemption Date will be payable to the Holders of Securities, or one or more
Predecessor Securities, of record at the close of business on the relevant
Record Dates referred to on the face hereof, all as provided in the Indenture.

               In addition to any redemption provided for in the immediately
preceding paragraphs, in the event of a sale by the Company after the Closing
Date and on or prior to November 1, 2001 of its Capital Stock (other than
Redeemable Stock) in a single transaction or series of transactions for an
aggregate purchase price equal to or exceeding $50 million, up to a maximum of
35% of the original aggregate principal amount of the Outstanding Securities
will, within 180 days of such sale, at the option of the Company, upon not less
than 30 nor more than 60 days' notice by mail, be redeemable from the net
proceeds thereof (but only to the extent such proceeds consist of cash or
readily marketable cash equivalents received in respect of the Company's Capital
Stock so sold, in each case net of all commissions, discounts, fees, expenses
and taxes incurred in respect thereof) at a Redemption Price equal to 112% of
the principal amount of the Securities to be redeemed plus accrued and unpaid
interest to the Redemption Date.

               The Securities do not have the benefit of any sinking fund
obligations.

               In the event of redemption, or purchase pursuant to an Offer to
Purchase, of this Security in part only, a new Security or Securities for the
unredeemed or unpurchased portion hereof will be issued in the name of the
Holder hereof upon the cancellation hereof.
<PAGE>   39

               The Indenture contains provisions for defeasance at any time of
the entire indebtedness of this Security or certain restrictive covenants and
Events of Default with respect to this Security, in each case upon compliance
with certain conditions set forth in the Indenture.

               If an Event of Default shall occur and be continuing, there may
be declared due and payable the Default Amount of the Securities, in the manner
and with the effect provided in the Indenture. The Default Amount in respect of
this Security as of any particular date shall equal 100% of the principal amount
payable in respect of this Security at the Stated Maturity hereof. Upon payment
of (i) the Default Amount so declared due and payable and any overdue
installment of interest in respect of this Security, (ii) any overdue principal
or premium payable on redemption or repurchase of this Security and (iii) as
provided on the face hereof, any interest on any overdue Default Amount,
principal, premium or interest in respect of this Security (to the extent that
the payment of such interest shall be legally enforceable), all of the Company's
obligations in respect of the payment of the principal of and any premium and
interest on this Security shall terminate.

               The Indenture provides that, subject to certain conditions, if a
Change of Control occurs, the Company shall be required to make an Offer to
Purchase for all of the Securities.

               Unless the context otherwise requires, references herein to the
principal amount of any Security mean, as of any day, (i) with respect to any
portion thereof required hereunder to be redeemed or repurchased on any
redemption or repurchase date on or prior to such day, the amount due and
payable in respect of such portion upon such redemption or repurchase date
(excluding premium and interest), (ii) with respect to any portion thereof not
required to be so redeemed or repurchased, but which has been declared due and
payable prior to the Stated Maturity thereof as provided in the Indenture, the
Default Amount in respect of such portion as of such day and (iii) with respect
to any portion thereof not required so to be redeemed or repurchased and not so
declared due and payable, such portion of the principal amount of such Security
payable at Stated Maturity thereof.

               The Indenture permits, with certain exceptions as therein
provided, the amendment thereof and the modification of the rights and
obligations of the Company and the rights of the Holders of the Securities under
the Indenture at any time by the Company and the Trustee after having received
the Required Consent (defined as follows). The Indenture also contains
provisions permitting those Persons giving the Required Consent, on behalf of
the Holders of all the Securities, to waive compliance by the Company with
certain provisions of the Indenture and certain past defaults under the
Indenture and their consequences. Any such consent or waiver by the Holder of
this Security shall be conclusive and binding upon such Holder and upon all
future Holders of this Security and of any Security issued upon the registration
of transfer hereof or in exchange herefor or in lieu hereof, whether or not
notation of such consent or waiver is made upon this Security.

               As used herein, "Required Consent" means, except as otherwise
expressly provided in the 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 the Securities for any action to (x) direct the time, method 

<PAGE>   40

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, any past default and its
consequences, and (ii) with respect to all other actions requiring the consent
of holders of the Securities, the consent of either (x) a majority in aggregate
principal amount at Stated Maturity of the Securities or (y) a majority in
aggregate principal amount at Stated Maturity of (I) the Securities, (II) the
September Notes, if the holders of the September Notes are being requested to
consent to such action with respect to the terms of the September Notes or the
September Indenture, (III) the October Notes, if the holders of the October
Notes are being requested to consent to such action with respect to the terms of
the October Notes or the October Indenture, (IV) the February Notes, if the
holders of the February Notes are being requested to consent to such action with
respect to the terms of the February Notes or the February Indenture and (V) any
other issue of unsubordinated, unsecured notes issued by the Company, if such
notes or the indenture pursuant to which such notes were issued both (A) require
the consent of the holders of such notes to such action and (B) provide that the
holders thereof will vote with the holders of the Securities with respect to
such action.

               As provided in and subject to the provisions of the Indenture,
the Holder of this Security shall not have the right to institute any proceeding
with respect to the Indenture or for the appointment of a receiver or trustee or
for any other remedy thereunder, unless such Holder shall have previously given
the Trustee written notice of a continuing Event of Default with respect to the
Securities, the Holders of not less than 25% in principal amount at Stated
Maturity of the Securities at the time Outstanding shall have made written
request to the Trustee to institute proceedings in respect of such Event of
Default as Trustee and offered the Trustee reasonable indemnity and the Trustee
shall not have received from the Holders of a majority in principal amount at
Stated Maturity of Securities at the time Outstanding a direction inconsistent
with such request, and shall have failed to institute any such proceeding,
within 60 days after receipt of such notice, request and offer of indemnity. The
foregoing shall not apply to certain suits described in the Indenture, including
any suit instituted by the Holder of this Security for the enforcement of any
payment of principal hereof or any premium or interest hereon on or after the
respective due dates expressed herein (or, in the case of redemption, on or
after the Redemption Date or, in the case of any purchase of this Security
required to be made pursuant to an Offer to Purchase, on or after the Purchase
Date.)

               No reference herein to the Indenture and no provision of this
Security or of the Indenture shall alter or impair the obligation of the
Company, which is absolute and unconditional, to pay the principal of (and
premium, if any) and interest on this Security at the times, place and rate, and
in the coin or currency, herein prescribed.

               As provided in the Indenture and subject to certain limitations
therein set forth, the transfer of this Security is registrable in the Security
Register, upon surrender of this Security for registration of transfer at the
office or agency of the Company in the Borough of Manhattan, The City of New
York, duly endorsed by, or accompanied by a written instrument of transfer in
form satisfactory to the Company and the Security Registrar duly executed by,
the Holder hereof or his attorney duly authorized in writing, and thereupon one
or more new Securities, of authorized denominations and for the same aggregate
principal amount, will be issued to the designated transferee or transferees.
<PAGE>   41

               The Securities are issuable only in registered form without
coupons in denominations of $1,000 and any integral multiple thereof. As
provided in the Indenture and subject to certain limitations therein set forth,
the Securities are exchangeable for a like aggregate principal amount of
Securities of like tenor of a different authorized denomination, as requested by
the Holder surrendering the same.

               No service charge shall be made for any such registration of
transfer or exchange, but the Company may require payment of a sum sufficient to
cover any tax or other governmental charge payable in connection therewith.

               Prior to due presentment of this 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 this Security is registered as the owner
hereof for all purposes, whether or not this Security be overdue, and neither
the Company, the Trustee nor any such agent shall be affected by notice to the
contrary.

               Interest on this Security shall be computed on the basis of a
360-day year of twelve 30-day months.

               All terms used in this Security which are defined in the
Indenture shall have the meanings assigned to them in the Indenture.

               The Indenture and this Security shall be governed by and
construed in accordance with the laws of the State of New York.

                            [FORM OF TRANSFER NOTICE]

               FOR VALUE RECEIVED the undersigned registered holder hereby 
sell(s), assign(s) and transfer(s) unto

Insert Taxpayer Identification No.


--------------------------------------------------------------------------------
Please print or typewrite name and address including zip code of assignee


--------------------------------------------------------------------------------
the within Note and all rights thereunder, hereby irrevocably constituting and
appointing ____________________________ attorney to transfer said Security on
the books of the Company with full power of substitution in the premises.


                     [THE FOLLOWING PROVISION TO BE INCLUDED
                ON ALL SECURITIES OTHER THAN EXCHANGE SECURITIES
             AND UNLEGENDED OFFSHORE PHYSICAL AND GLOBAL SECURITIES]
<PAGE>   42

               In connection with any transfer of this Security occurring prior
to the date which is the earlier of (i) the date the Shelf Registration
Statement with respect to resales of the Securities is declared effective or
(ii) the end of the period referred to in Rule 144(k) under the Securities Act,
the undersigned confirms that without utilizing any general solicitation or
general advertising that:

                                   [Check One]

[ ](a)  this Security is being transferred in compliance with the exemption from
        registration under the Securities Act of 1933, as amended, provided by
        Rule 144A thereunder.

[ ](b)  this Security is being transferred other than in accordance with (a)
        above and documents are being furnished which comply with the conditions
        of transfer set forth in this Security and the Indenture.

If none of the foregoing boxes is checked, the Trustee shall not be obligated to
register this Security in the name of any Person other than the Holder hereof
unless and until the conditions to any such transfer of registration set forth
herein and in Section 307 of the Indenture shall have been satisfied.

Date:_____________________          ____________________________________________
                                    NOTICE:
                                    The signature to this assignment must
                                    correspond with the name as written upon the
                                    face of the within-mentioned instrument in
                                    every particular, without alteration or any
                                    change whatsoever.


TO BE COMPLETED BY PURCHASER IF (a) ABOVE IS CHECKED.

        The undersigned represents and warrants that it is purchasing this
Security for its own account or an account with respect to which it exercises
sole investment discretion and that it and any such account is a "qualified
institutional buyer" within the meaning of Rule 144A under the Securities Act of
1933, as amended, and is aware that the sale to it is being made in reliance on
Rule 144A and acknowledges that it has received such information regarding the
Company as the undersigned has requested pursuant to Rule 144A or has determined
not to request such information and that it is aware that the transferor is
relying upon the undersigned's foregoing representations in order to claim the
exemption from registration provided by Rule 144A.

Date:_____________________          ____________________________________________
                                    NOTICE: To be executed by an executive 
                                    officer.

                       OPTION OF HOLDER TO ELECT PURCHASE

               If you want to elect to have this Security purchased in its 
entirety by the Company pursuant to Section 1013 of the Indenture, check the
box: [ ]
<PAGE>   43

               If you want to elect to have only a part of the principal amount
at Stated Maturity of this Security purchased by the Company pursuant to Section
1013 of the Indenture, state the portion of such amount: $_________

Dated:                       Your Signature:____________________________________
                                            (Sign exactly as name appears
                                            on the other side of this Security)

Signature Guarantee:______________________________________

(Signature must be guaranteed by a financial institution that is a member of the
Securities Transfer Agent Medallion Program ("STAMP"), the Stock Exchange
Medallion Program ("SEMP"), the New York Stock Exchange, Inc. Medallion
Signature Program ("MSP") or such other signature guarantee program as may be
determined by the Security Registrar in addition to, or in substitution for,
STAMP, SEMP or MSP, all in accordance with the Securities Exchange Act of 1934,
as amended.)


SECTION 204.  Form of Trustee's Certificate of Authentication.

Dated:

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


                                            Harris Trust and Savings Bank,
                                            as Trustee


                                            By ________________________________
                                               Authorized Signatory


SECTION 205. Restrictive Legends. Unless and until a Security is exchanged for
an Exchange Security or sold in connection with an effective Shelf Registration
Statement pursuant to the Registration Rights Agreement, (i) each U.S. Global
Security and each U.S. Physical Security shall bear the legend set forth below
on the reverse thereof and (ii) each Offshore Physical Security and each
Offshore Global Security shall bear the legend set forth below on the reverse
thereof, until at least the 41st day after the Closing Date and receipt by the
Company and the Trustee of a certificate substantially in the form of Exhibit A
hereto:

               THIS SENIOR NOTE HAS NOT BEEN REGISTERED UNDER THE U.S.
SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND ACCORDINGLY, MAY
NOT BE OFFERED OR SOLD WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR
BENEFIT OF, U.S. PERSONS EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE. BY ITS
ACQUISITION HEREOF, THE HOLDER 

<PAGE>   44


(1) REPRESENTS THAT (A) IT IS A "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED IN
RULE 144A UNDER THE SECURITIES ACT), (B) IT IS NOT A U.S. PERSON AND IS
ACQUIRING THIS SENIOR NOTE IN AN OFFSHORE TRANSACTION IN COMPLIANCE WITH
REGULATION S UNDER THE SECURITIES ACT, OR (C) IT IS AN INSTITUTIONAL "ACCREDITED
INVESTOR" (AS DEFINED IN RULE 501(a)(1), (2), (3) OR (7) OF REGULATION D UNDER
THE SECURITIES ACT) (AN "INSTITUTIONAL ACCREDITED INVESTOR"), (2) AGREES THAT IT
WILL NOT, WITHIN TWO YEARS AFTER THE ORIGINAL ISSUANCE OF THIS SENIOR NOTE,
RESELL OR OTHERWISE TRANSFER THIS SENIOR NOTE EXCEPT (A) TO NEXTEL
COMMUNICATIONS, INC. OR ANY SUBSIDIARY THEREOF, (B) TO A QUALIFIED INSTITUTIONAL
BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES ACT, (C) OUTSIDE THE
UNITED STATES IN AN OFFSHORE TRANSACTION IN COMPLIANCE WITH RULE 904 UNDER THE
SECURITIES ACT, (D) PURSUANT TO THE EXEMPTION FROM REGISTRATION PROVIDED BY RULE
144 UNDER THE SECURITIES ACT (IF AVAILABLE), (E) INSIDE THE UNITED STATES TO AN
INSTITUTIONAL ACCREDITED INVESTOR THAT, PRIOR TO SUCH TRANSFER, FURNISHES TO THE
TRUSTEE A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS
RELATING TO THE RESTRICTIONS ON TRANSFER OF THIS SENIOR NOTE (THE FORM OF WHICH
LETTER CAN BE OBTAINED FROM THE TRUSTEE) AND IF SUCH TRANSFER IS IN RESPECT OF
AN AGGREGATE PRINCIPAL AMOUNT OF SENIOR NOTES OF LESS THAN $250,000, AN OPINION
OF COUNSEL ACCEPTABLE TO NEXTEL COMMUNICATIONS, INC. THAT SUCH TRANSFER IS IN
COMPLIANCE WITH THE SECURITIES ACT, OR (F) AFTER REGISTRATION OR PURSUANT TO AN
EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT AND (3) AGREES THAT IT
WILL DELIVER TO EACH PERSON TO WHOM THIS SENIOR NOTE IS TRANSFERRED A NOTICE
SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. IN CONNECTION WITH ANY TRANSFER OF
THIS SENIOR NOTE WITHIN THE TIME PERIOD REFERRED TO ABOVE, THE HOLDER MUST CHECK
THE APPROPRIATE BOX SET FORTH ON THE REVERSE HEREOF RELATING TO THE MANNER OF
SUCH TRANSFER AND SUBMIT THIS CERTIFICATE TO THE TRUSTEE. IF THE PROPOSED
TRANSFEREE IS AN INSTITUTIONAL ACCREDITED INVESTOR, THE HOLDER MUST, PRIOR TO
SUCH TRANSFER, FURNISH TO THE TRUSTEE AND NEXTEL COMMUNICATIONS, INC. SUCH
CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS EITHER OF THEM MAY
REASONABLY REQUIRE TO CONFIRM THAT SUCH TRANSFER IS BEING MADE PURSUANT TO AN
EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION
REQUIREMENTS OF THE SECURITIES ACT. AS USED HEREIN, THE TERMS "OFFSHORE
TRANSACTION," "UNITED STATES" AND "U.S. PERSON" HAVE THE MEANINGS GIVEN TO THEM
BY REGULATION S UNDER THE SECURITIES ACT. THE INDENTURE CONTAINS A PROVISION
REQUIRING THE TRUSTEE TO REFUSE TO REGISTER ANY TRANSFER OF THIS SENIOR NOTE IN
VIOLATION OF THE FOREGOING RESTRICTIONS.
<PAGE>   45

               Each Global Security, whether or not an Exchange Security, shall
also bear the following legend on the reverse thereof:

               UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, TO THE COMPANY OR ITS AGENT FOR
REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS
REGISTERED IN THE NAME OF CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY
AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY OR SUCH OTHER
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY OR SUCH OTHER NAME AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (AND
ANY PAYMENT HEREON IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED
BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY), ANY TRANSFER,
PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS
WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

               TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS
IN WHOLE, BUT NOT IN PART, TO NOMINEES OF CEDE & CO., OR TO A SUCCESSOR THEREOF
OR SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL SECURITY
SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH
IN SECTION 307 OF THE INDENTURE.


                                  ARTICLE THREE

                                 The Securities

SECTION 301.  Title and Terms.

               The aggregate principal amount at Stated Maturity of Securities
which may be authenticated and delivered under this Indenture is limited to
$300,000,000, except for Securities authenticated and delivered upon
registration of transfer of, or in exchange for, or in lieu of, other Securities
pursuant to Section 304, 305, 308, 906 or 1108 or in connection with an Offer to
Purchase pursuant to Section 1013.

               The Securities shall be known and designated as the "Senior
Serial Redeemable Notes due 2008" of the Company. Their Stated Maturity shall be
November 1, 2008 and they shall bear cash interest at the rate of 12% per annum,
from November 4, 1998 or from the most recent Interest Payment Date to which
interest has been paid or duly provided for, as the case may be, payable
semi-annually on May 1 and November 1, commencing May 1, 1999 until the
principal thereof is paid or made available for payment.

               The principal of (and premium, if any) and interest on the
Securities shall be payable at the office or agency of the Company in the
Borough of Manhattan, The City of New 

<PAGE>   46

York maintained for such purpose and at any other office or agency maintained by
the Company for such purpose; provided, however, that at the option of the
Company payment of interest, may be made by check mailed to the address of the
Person entitled thereto as such address shall appear in the Security Register.

               The Company may be required to make an Offer to Purchase the
Securities as provided in Section 1013.

               The Securities shall be redeemable as provided in Article Two and
Article Eleven.

               The Securities shall be subject to Defeasance and/or Covenant
Defeasance as provided in Article Twelve.


SECTION 302.  Denominations.

               The Securities shall be issuable only in registered form without
coupons and only in denominations of $1,000 principal amount and any integral
multiple thereof.


SECTION 303.  Execution, Authentication, Delivery and Dating.

               The Securities shall be executed on behalf of the Company by its
Chairman of the Board, its President or one of its Vice Presidents, under its
corporate seal reproduced thereon attested by its Secretary or one of its
Assistant Secretaries. 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 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 as in
this Indenture provided and not otherwise.

               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 

<PAGE>   47

such certificate upon any Security shall be conclusive evidence, and the only
evidence, that such Security has been duly authenticated and delivered
hereunder.


SECTION 304.  Temporary Securities.

               Pending the preparation of definitive Securities, the Company may
execute, and upon 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 are issued, the Company will cause
definitive Securities to be prepared without unreasonable delay. After the
preparation of definitive Securities, the temporary Securities shall be
exchangeable for definitive Securities upon surrender of the temporary
Securities 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 the Company shall execute and the Trustee shall
authenticate and deliver in exchange therefor a like principal amount of
definitive Securities of authorized denominations and of a like tenor. Until so
exchanged the temporary Securities shall in all respects be entitled to the same
benefits under this Indenture as definitive Securities.


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 it may prescribe, the Company shall provide
for the registration of Securities and of transfers of Securities. The Trustee
is hereby appointed "Security Registrar" for the purpose of registering
Securities and transfers of Securities as herein provided.

               Upon surrender for registration of transfer of any Security 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 any authorized denominations and of a like aggregate principal
amount and tenor. No such transfer shall be effected until, and such transferee
shall succeed to the rights of a Holder only upon, final acceptance and
registration of the transfer by the Security Registrar in the Security Register.
Prior to the registration of any transfer by a Holder as provided herein, the
Company, the Trustee and any agent of the Company shall treat the person in
whose name the Security is registered as the owner thereof for all purposes
whether or not the Security shall be overdue, and neither the Company, the
Trustee, nor any such agent shall be affected by notice to the contrary.
Furthermore, any Holder of a Global Security shall, by acceptance of such Global
Security, agree that transfers of beneficial interests 


<PAGE>   48

in such Global Security may be effected only through a book entry system
maintained by the Holder of such Global Security (or its agent) and that
ownership of a beneficial interest in the Security shall be required to be
reflected in a book entry.

               At the option of the Holder, Securities may be exchanged for
other Securities (including an exchange of securities for Exchange Securities)
of any authorized denominations and of a like aggregate principal amount and
tenor, upon surrender of the Securities to be exchanged at such office or agency
provided, that no exchange of Securities for Exchange Securities shall occur
until a Registration Statement shall have been declared effective by the
Commission and that Securities that are exchanged for Exchange Securities
pursuant to such Registration Statement shall be canceled by the Trustee.
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 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, 906 or 1108 or in accordance with any
Offer to Purchase pursuant to Section 1013, and in any such case not involving
any transfer.

               The Company shall not be required (i) to issue, register the
transfer of or exchange any Security 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 1104 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.

SECTION 306.  Book-Entry Provisions for Global Security.

               (a) The Global Security initially shall (i) be registered in the
name of the Depository for such Global Security or the nominee of such
Depository; (ii) be delivered to the 


<PAGE>   49

Trustee as custodian for such Depository; and (iii) bear legends as set forth in
Section 205.

               Members of, or participants in, the Depository ("Agent Members")
shall have no rights under this Indenture with respect to any Global Security
held on their behalf by the Depository, or the Trustee as its custodian, or
under the Global Security and the Depository may be treated by the Company, the
Trustee and any agent of the Company or the Trustee as the absolute owner of
such Global Security for all purposes whatsoever. Notwithstanding the foregoing,
nothing herein shall prevent the Company, the Trustee or any agent of the
Company or the Trustee, from giving effect to any written certification, proxy
or other authorization furnished by the Depository or impair, as between the
Depository and its Agent Members, the operation of customary practices governing
the exercise of the rights of a holder of any Security.

               (b) Transfers of a Global Security shall be limited to transfers
of such Global Security in whole, but not in part, to the Depository, its
successors or their respective nominees. Interests of beneficial owners in a
Global Security may be transferred in accordance with the rules and procedures
of the Depository and the provisions of Section 307. In addition, U.S. Physical
Securities and Offshore Physical Securities shall be transferred to all
beneficial owners in exchange for their beneficial interests in the U.S. Global
Securities or Offshore Global Securities, respectively, if (i) the Depository
notifies the Company that it is unwilling or unable to continue as Depository
for the U.S. Global Securities or Offshore Global Securities, as the case may
be, and a successor depository is not appointed by the Company within 90 days of
such notice, (ii) an Event of Default has occurred and is continuing and the
Security Registrar has received a request therefor from the Depository or (iii)
in accordance with the rules and procedures of the Depository and the provisions
of Section 307.

               (c) In connection with any transfer of a portion of the
beneficial interests in the Global Security to beneficial owners pursuant to
paragraph (b) of this Section, the Security Registrar shall reflect on the
Security Register the date and a decrease in the principal amount of the Global
Security in an amount equal to the principal amount of the beneficial interest
in the Global Security to be transferred, and the Company shall execute, and the
Trustee shall authenticate and deliver, one or more Physical Securities of like
tenor and amount.

               (d) In connection with the transfer of an entire U.S. Global
Security or Offshore Global Security to beneficial owners pursuant to paragraph
(b) of this Section, such U.S. Global Security or Offshore Global Security shall
be deemed to be surrendered to the Trustee for cancellation, and the Company
shall execute, and the Trustee shall authenticate and deliver, to each
beneficial owner identified by the Depository in exchange for its beneficial
interest in such U.S. Global Security or Offshore Global Security, as the case
may be, an equal aggregate principal amount of U.S. Physical Securities or
Offshore Physical Securities of authorized denominations.

               (e) Any Physical Security delivered in exchange for an interest
in the Global Security pursuant to paragraph (b), (c) or (d) of this Section
shall, except as otherwise provided by paragraph (d) of Section 307 bear the
legend regarding transfer restrictions applicable to the Physical Securities set
forth in Section 205.
<PAGE>   50

               (f) The registered holder of a Global Security may grant proxies
and otherwise authorize any person, including Agent Members and persons that may
hold interests through Agent Members, to take any action which a Holder is
entitled to take under this Indenture or the Securities.


SECTION 307.  Special Transfer Provisions.

               Unless and until a Security is exchanged for an Exchange Security
or sold in connection with an effective Shelf Registration Statement pursuant to
the Registration Rights Agreement, the following provisions shall apply:

               (a) Transfers to QIBs. The following provisions shall apply with
respect to the registration of any proposed transfer of a Physical Security or
an interest in the Global Security prior to the removal of the Private Placement
Legend to a QIB (excluding Non-U.S.
Persons):

               (i) If the Security to be transferred consists of (x) (A) U.S.
        Physical Securities or (B) an interest in an Offshore Global Security
        prior to the removal of the Private Placement Legend, the Security
        Registrar shall register the transfer if such transfer is being made by
        a proposed transferor who has checked the box provided for on the form
        of security stating, or has otherwise advised the Company and the
        Security Registrar in writing, that the sale has been made in compliance
        with the provisions of Rule 144A, to a transferee who has signed the
        certification provided for on the form of Security stating, or has
        otherwise advised the Company and the Security Registrar in writing,
        that it is purchasing the Security for its own account or an account
        with respect to which it exercises sole investment discretion and that
        it and any such account is a QIB within the meaning of Rule 144A, and is
        aware that the sale to it is being made in reliance on Rule 144A and
        acknowledges that it has received such information regarding the Company
        as it has requested pursuant to Rule 144A or has determined not to
        request such information and that it is aware that the transferor is
        relying upon its foregoing representations in order to claim the
        exemption from registration provided by Rule 144A or (y) an interest in
        a U.S. Global Security, the transfer of such interest may be effected
        only through the book entry system maintained by the Depository.

               (ii) If the proposed transferee is an Agent Member, and the
        Security to be transferred consists of U.S. Physical Securities, upon
        receipt by the Security Registrar of the documents referred to in clause
        (i) and instructions given in accordance with the Depository's and the
        Security Registrar's procedures, the Security Registrar shall reflect in
        the Security Register the date and an increase in the principal amount
        at maturity of the U.S. Global Security in an amount equal to the
        principal amount at maturity of the U.S. Physical Securities to be
        transferred, and the Trustee shall cancel the U.S. Physical Securities
        so transferred.

               (b) Transfers to Non-QIB Institutional Accredited Investors. The
following provisions shall apply with respect to the registration of any
proposed transfer of a Security to any Institutional Accredited Investor which
is not a QIB (excluding Non-U.S. Persons):
<PAGE>   51

               (i) The Security Registrar shall register the transfer of any
        Security, whether or not such Security bears the Private Placement
        Legend, if (x) the requested transfer is after the time period referred
        to in Rule 144(k) under the Securities Act as in effect with respect to
        such transfer or (y) the proposed transferee has delivered to the
        Security Registrar (A) a certificate substantially in the form of
        Exhibit B hereto and (B) if the aggregate principal amount of the Notes
        being transferred is less than $250,000 at the time of such transfer, an
        Opinion of Counsel acceptable to the Company that such transfer is in
        compliance with the Securities Act.

               (ii) If the proposed transferor is an Agent Member holding a
        beneficial interest in the U.S. Global Security, upon receipt by the
        Security Registrar of (x) the documents, if any, required by the
        preceding paragraph (i), and (y) instructions given in accordance with
        the Depositary's and the Security Registrar's procedures, the Security
        Registrar shall reflect on its books and records the date and a decrease
        in the principal amount of the U.S. Global Security in an amount equal
        to the principal amount of the beneficial interest in the U.S. Global
        Security to be transferred, and the Company shall execute, and the
        Trustee shall authenticate and deliver, one or more U.S. Physical
        Securities of like tenor and amount.

               (c) Transfers of Interests in the Offshore Global Securities or
Offshore Physical Securities. The following provisions shall apply with respect
to any transfer of interests in the Offshore Global Securities or Offshore
Physical Securities:

               (i) prior to removal of the Private Placement Legend from an
        Offshore Global Security or Offshore Physical Security pursuant to
        Section 205, the Security Registrar shall refuse to register such
        transfer unless such transfer complies with Section 307(a) or Section
        307(d), as the case may be; and

               (ii) after such removal, the Security Registrar shall register
        the transfer of any such Security without requiring any additional
        certification.

               (d) Transfers to Non-U.S. Persons at Any Time. The following
provisions shall apply with respect to any transfer of a Security to a Non-U.S.
Person:

               (i) The Security Registrar shall register any proposed transfer
        to any Non-U.S. Person if the Security to be transferred is a U.S.
        Physical Security or an interest in a U.S. Global Security only upon
        receipt of a certificate substantially in the form of Exhibit C hereto
        from the proposed transferor.

               (ii) (A) If the proposed Transferor is an Agent Member holding a
        beneficial interest in a U.S. Global Security, upon receipt by the
        Security Registrar of (x) the documents required by paragraph (i) and
        (y) instructions in accordance with the Depositary's and the Security
        Registrar's procedures, the Security Registrar shall reflect on its
        books and records the date and a decrease in the principal amount of
        such U.S. Global Security in an amount equal to the principal amount of
        the beneficial interest in 

<PAGE>   52

        the U.S. Global Security to be transferred, and (B) if the proposed
        transferee is an Agent Member, upon receipt by the Security Registrar of
        instructions given in accordance with the Depositary's and the Security
        Registrar's procedures, the Security Registrar shall reflect on its
        books and records the date and an increase in the principal amount of
        the Offshore Global Security in an amount equal to the principal amount
        of the U.S. Physical Securities or the U.S. Global Security, as the case
        may be, to be transferred, and the Trustee shall cancel the Physical
        Security, if any, so transferred or decrease the amount of the U.S.
        Global Security.

               (e) Private Placement Legend. Upon the transfer, exchange or
replacement of Securities not bearing the Private Placement Legend, the Security
Registrar shall deliver Securities that do not bear the Private Placement
Legend. Upon the transfer, exchange or replacement of securities bearing the
Private Placement Legend, the Security Registrar shall deliver only Securities
that bear the Private Placement Legend unless either (i) the circumstances
contemplated by Section 205 exist or (ii) there is delivered to the Trustee an
Opinion of Counsel reasonably satisfactory to the Company and the Trustee to the
effect that neither such legend nor the related restrictions on transfer are
required in order to maintain compliance with the provisions of the Securities
Act.

               (f) General. By its acceptance of any Security bearing the
Private Placement Legend, each Holder of such a Security acknowledges the
restrictions on transfer of such Security set forth in this Indenture and in the
Private Placement Legend and agrees that it will transfer such Security only as
provided in this Indenture. The Security Registrar shall not register a transfer
of any Security unless such transfer complies with the restrictions on transfer
of such Security set forth in the Private Placement Legend and in this
Indenture. In connection with any transfer of Securities, each Holder agrees by
its acceptance of the Securities to furnish the Trustee or the Company such
certifications, legal opinions or other information as either of them may
reasonably require to confirm that such transfer is being made pursuant to an
exemption from, or a transaction not subject to, the registration requirements
of the Securities Act; provided that the Trustee shall not be required to
determine (but may rely on a determination made by the Company with respect to)
the sufficiency of any such certifications, legal opinions or other information.

               The Trustee shall retain copies of all letters, notices and other
written communications received pursuant to Section 306 or this Section 307. The
Company shall have the right to inspect and make copies of all such letters,
notices or other written communications at any reasonable time upon the giving
of reasonable written notice to the Trustee.


SECTION 308.  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 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 

<PAGE>   53

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 upon its request the Trustee shall authenticate and deliver, in lieu of any
such destroyed, lost or stolen Security, a new Security 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 its discretion
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 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 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 309.  Payment of Interest; Interest Rights Preserved.

               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 which is payable, but is not
punctually paid or duly provided for, on any Interest Payment Date (herein
called "Defaulted Interest") shall 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 (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 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


<PAGE>   54

        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 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 given
        to each Holder in the manner specified in Section 106, 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 (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 in any
        other lawful manner not inconsistent with the requirements of any
        securities exchange on which the 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 310.  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 309) interest on such Security and for all other
purposes whatsoever, whether or not such Security be overdue, and neither the
Company, the Trustee nor any agent of the Company or the Trustee shall be
affected by notice to the contrary.


SECTION 311.  Cancellation.

               All Securities surrendered for payment, redemption, registration
of transfer or exchange or for credit against any Offer to Purchase pursuant to
Section 1013 shall, if surrendered to any Person other than the Trustee, be
delivered to the Trustee and shall be promptly canceled by it. The Company may
at any time deliver to the Trustee for cancellation 

<PAGE>   55

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 canceled by the Trustee. No Securities shall be
authenticated in lieu of or in exchange for any Securities canceled as provided
in this Section, except as expressly permitted by this Indenture. All canceled
Securities held by the Trustee shall be disposed of as directed by a Company
Order; provided, however, that the Trustee shall not be required to destroy
canceled Securities.


SECTION 312.  Computation of Interest.

               Interest on the Securities shall be computed on the basis of a
360-day year of twelve 30-day months.


SECTION 313.  CUSIP, CINS and ISIN Numbers.

               The Company in issuing the Securities may use "CUSIP," "CINS" and
"ISIN" numbers (if then generally in use), and, if so, the Trustee shall use the
"CUSIP," "CINS" and "ISIN" numbers in notices of redemption or repurchase as a
convenience to Holders; provided that any such notice may state that no
representation is made as to the correctness of such numbers either as printed
on the Securities or as contained in any notice of a redemption or repurchase
and that reliance may be placed only on the other identification numbers printed
on the Securities, and any such redemption or repurchase shall not be affected
by any defect in or omission of such numbers.


                                  ARTICLE FOUR

                           Satisfaction and Discharge

SECTION 401.  Satisfaction and Discharge of Indenture.

               This Indenture shall cease to be of further effect (except as to
any surviving rights of registration of transfer or exchange of Securities
herein expressly provided for), 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) all Securities theretofore authenticated and delivered
               (other than (i) Securities which have been destroyed, lost or
               stolen and which have been replaced or paid as provided in
               Section 308 and (ii) Securities for whose payment money has
               theretofore been deposited in trust or segregated and held in
               trust by 

<PAGE>   56

                the Company and thereafter repaid to the Company or discharged
                from such trust, as provided in Section 1003) have been
                delivered to the Trustee for cancellation; or

                        (B) all such Securities not theretofore delivered to the
                Trustee for cancellation

                                (i) have become due and payable, or

                                (ii) will become due and payable at their Stated
                        Maturity within one year, or

                                (iii) are to be called for redemption within one
                        year under arrangements satisfactory to the Trustee for
                        the giving of notice of redemption by the Trustee in the
                        name, and at the expense, of the Company,

                and the Company, in the case of (i), (ii) or (iii) 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
                discharge the entire indebtedness on such Securities not
                theretofore delivered to the Trustee for cancellation, for
                principal (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; and

                (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.

Notwithstanding the satisfaction and discharge of this Indenture pursuant to
this Article Four, the obligations of the Company to the Trustee under Section
607, the obligations of the Trustee to any Authenticating Agent under Section
614 and, 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 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) 

<PAGE>   57

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, 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):

                (1) default in the payment of the principal of (or premium, if
        any, on) any Security at its Maturity; or

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

                (3) default, on the applicable Purchase Date, in the purchase of
        Securities required to be purchased by the Company pursuant to an Offer
        to Purchase as to which an Offer has been mailed to Holders or failure
        to make an Offer to Purchase as required hereunder; or

                (4) default in the performance, or breach, of Section 801; or

                (5) default in the performance, or breach, of any covenant or
        warranty of the Company in this Indenture (other than a covenant or
        warranty a default whose performance or whose breach is elsewhere in
        this Section specifically dealt with) or in the Securities, 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 principal amount at Stated Maturity of the Outstanding Securities
        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

                (6) a default or defaults under any bond(s), debenture(s),
        note(s) or other evidence(s) of Debt for money borrowed by the Company
        or any Restricted Subsidiary (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 for money borrowed by the Company or any
        Restricted Subsidiary) having, individually or in the aggregate, a
        principal or similar amount outstanding of at least $25,000,000, whether
        such Debt now

<PAGE>   58

        exists or shall hereafter be created, which default or defaults shall
        constitute a failure to pay any portion of the principal or similar
        amount of such Debt when due and payable after the expiration of any
        applicable grace period with respect thereto or shall have resulted in
        such Debt becoming or being declared due and payable; or

               (7) a final judgment or final judgments for the payment of money
        are entered against the Company or any Restricted Subsidiary in an
        aggregate amount in excess of $25,000,000 by a court or courts of
        competent jurisdiction, which judgments remain undischarged or unbonded
        for a period (during which execution shall not be effectively stayed) of
        60 days after the right to appeal all such judgments has expired; or

               (8) 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
        Restricted Subsidiary in an involuntary case or proceeding under any
        applicable Federal or State bankruptcy, insolvency, reorganization or
        other similar law or (B) a decree or order adjudging the Company or any
        Restricted 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 Restricted 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 Restricted Subsidiary or of any
        substantial part of the property of the Company or any Restricted
        Subsidiary, or ordering the winding up or liquidation of the affairs of
        the Company or any Restricted Subsidiary, 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; or

               (9) the commencement by the Company or any Restricted 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 the Company or any Restricted Subsidiary to the entry of
        a decree or order for relief in respect of the Company or any Restricted
        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 the Company or any Restricted Subsidiary, or the
        filing by the Company or any Restricted Subsidiary of a petition or
        answer or consent seeking reorganization or relief under any applicable
        Federal or State law, or the consent by the Company or any Restricted
        Subsidiary to the filing of such petition or to the appointment of or
        taking possession by a custodian, receiver, liquidator, assignee,
        trustee, sequestrator or similar official of the Company or any
        Restricted Subsidiary or of any substantial part of the property of the
        Company or any Restricted Subsidiary, or the making by the Company or
        any Restricted Subsidiary of an assignment for the benefit of creditors,
        or the admission by the Company or any Restricted Subsidiary 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 Restricted Subsidiary
        in furtherance of any such action.

<PAGE>   59

SECTION 502.  Acceleration of Maturity; Rescission and Annulment.

               If an Event of Default (other than an Event of Default specified
in Section 501(8) or (9)) occurs and is continuing, then and in every such case
the Trustee or the Holders of not less than 25% in principal amount at Stated
Maturity of the Outstanding Securities may declare the Default Amount of all the
Securities 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 shall become immediately due and
payable. If an Event of Default specified in Section 501(8) or (9) occurs, the
Default Amount of, and any accrued interest on, the Securities then Outstanding
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 particular Security as of
any particular date shall equal 100% of the principal amount payable in respect
of the Security at the Stated Maturity thereof.

               At any time after such a declaration of acceleration has been
made and before a judgment or decree for payment of the money due has been
obtained by the Trustee as hereinafter in this Article provided, the Holders of
a majority in principal amount at Stated Maturity of the Outstanding Securities,
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 (without
               duplication of any amount thereof paid or deposited pursuant to
               Clause (B) or (C) below),

                      (B) the principal of (and premium, if any, on) any
               Securities which have become due otherwise than by such
               declaration of acceleration (including any Securities required to
               have been purchased on the Purchase Date pursuant to an Offer to
               Purchase made by the Company) and, to the extent that payment of
               such interest is lawful, interest thereon at the rate provided by
               the Securities (without duplication of any amount thereof paid or
               deposited pursuant to Clause (A) above or Clause (C) below),

                      (C) to the extent that payment of such interest is lawful,
               interest upon overdue interest at the rate provided by the
               Securities (without duplication of any amount thereof paid or
               deposited pursuant to Clause (A) or (B) above), 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


<PAGE>   60

               (2) all Events of Default, other than the non-payment of the
        principal of Securities 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.

               Unless the context otherwise requires, references in this
Indenture to the principal amount of any Security mean, as of any day, (i) with
respect to any portion thereof required thereunder to be redeemed or repurchased
on any redemption or repurchase date on or prior to such day, the amount due and
payable in respect of such portion upon such redemption or repurchase date
(excluding premium and interest), (ii) with respect to any portion thereof not
required to be so redeemed or repurchased, but which has been declared due and
payable prior to the Stated Maturity thereof, the Default Amount in respect of
such portion as of such day and (iii) with respect to any portion thereof not
required so to be redeemed or repurchased and not so declared due and payable,
such portion of the principal amount of such Security payable at Stated Maturity
thereof.


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 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 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,

the Company will, upon demand of the Trustee, pay to the Trustee, for the
benefit of the Holders of such Securities, 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 provided by the Securities, and, in addition thereto, such further amount
as shall be sufficient to cover the costs and expenses of collection, including
the reasonable compensation, expenses, disbursements and advances of the
Trustee, its agents and counsel.

               If an Event of Default occurs and is continuing, the Trustee may
in its discretion proceed to protect and enforce its rights and the rights of
the Holders by such appropriate judicial proceedings as the Trustee shall deem
most effectual 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.

<PAGE>   61

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 or other property payable or deliverable on 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.


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
<PAGE>   62

               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.


SECTION 507.  Limitation on Suits.

               No Holder of any Security 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;

               (2) the Holders of not less than 25% in principal amount at
        Stated Maturity of the Outstanding Securities 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 to the Trustee reasonable
        indemnity against the costs, expenses and liabilities to be incurred in
        compliance with such request;

               (4) the Trustee for 60 days after its receipt of such notice,
        request and offer 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 at Stated Maturity of the Outstanding
        Securities;

it being understood and intended that no one or more 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 Holders,
or to obtain or to seek to obtain priority or preference over any other Holders
or to enforce any right under this Indenture, except in the manner herein
provided and for the equal and ratable benefit of all the 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 309) interest on such Security on the respective Stated Maturities
expressed in such Security (or, in the case of redemption, on the Redemption

<PAGE>   63

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 308, 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.


SECTION 511.  Delay or Omission Not Waiver.

               No delay or omission of the Trustee or of any Holder of any
Security 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, provided that

               (1) such direction shall not be in conflict with any rule of law
        or with this Indenture, and
<PAGE>   64

               (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 the Securities, waive any past
default hereunder and its consequences, except a default

               (1) in the payment of the principal of (or premium, if any) or
        interest on any Security (including any Security 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 affected.

               Upon any such waiver, such default shall cease to exist, and any
Event of Default arising therefrom shall be deemed to have been cured, for every
purpose of this Indenture; but no such waiver shall extend to any subsequent or
other default or impair any right consequent thereon.


SECTION 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, suffered 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 usury, 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.
<PAGE>   65


                                   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.

               The Trustee shall give the Holders notice of any Default
hereunder as and to the extent provided by the Trust Indenture Act; provided,
however, that in the case of any Default of the character specified in Section
501(5), no such notice to Holders 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:

               (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 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;
<PAGE>   66

               (d) the Trustee may consult with counsel and the 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 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;

               (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 (subject to reasonable
        confidentiality arrangements as may be proposed by the Company) to
        examine the books, records and premises of the Company, personally or by
        agent or attorney; and

               (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.


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

               The recitals contained herein and in the Securities, 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 makes no representations as to the validity or sufficiency of this
Indenture or of the Securities. The Trustee shall not be accountable for the use
or application by the Company of Securities or the proceeds thereof.


SECTION 605.  May Hold Securities.

               The Trustee, any Authenticating Agent, any Paying Agent, any
Security Registrar or any other agent of the Company, in its individual or any
other capacity, may become the owner or pledgee of Securities 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.

<PAGE>   67

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 in writing with the Company.


SECTION 607.  Compensation and Reimbursement.

               The Company agrees:

               (1) to pay to the Trustee from time to time such compensation as
        the Company and the Trustee shall from time to time agree in writing 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 and all loss, damage, claim, liability or expense incurred
        without negligence or bad faith on its part, including taxes (other than
        taxes based upon, measured by or determined by the revenue or income of
        the Trustee), arising out of or in connection with the acceptance or
        administration of this trust, including the costs and expenses of
        defending itself against any claim or liability in connection with the
        exercise or performance of any of its powers or duties hereunder.

               The Trustee shall have a lien prior to the Securities as to all
property and funds held by it hereunder for any amount owing to it pursuant to
this Section 607, except with respect to funds held in trust for the benefit of
the Holders of particular Securities.

               When the Trustee incurs expenses or renders services in
connection with an Event of Default specified in Section 501(8) or Section
501(9), the expenses (including the reasonable charges and expenses of its
counsel) and the compensation for the services are intended to constitute
expenses of administration under any applicable Federal or state bankruptcy,
insolvency or other similar law.

               The provisions of this Section shall survive any termination of
this Indenture.
<PAGE>   68


SECTION 608.  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.


SECTION 609.  Corporate Trustee Required; Eligibility.

               There shall at all times be a Trustee hereunder which 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 Chicago, Illinois or the Borough of Manhattan, The City of New
York. If such Person 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 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 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 in accordance with the
applicable requirements of Section 611.

               (b) The Trustee may resign at any time by giving written notice
thereof to the Company. If an instrument of acceptance by a successor Trustee in
accordance with the applicable requirements of Section 611 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.

               (c) The Trustee may be removed at any time by Act of the Holders
of a majority in principal amount at Stated Maturity of the Outstanding
Securities, delivered to the Trustee and to the Company. If an instrument of
acceptance by a successor Trustee in accordance with the applicable requirements
of Section 611 shall not have been delivered to the Trustee within 30 days after
the giving of such notice of removal, the Trustee may petition any court of
competent jurisdiction for the appointment of a successor Trustee.

               (d) If at any time:

               (1) the Trustee shall fail to comply with Section 608 after
        written request 


<PAGE>   69

        therefor by the Company or by any Holder who has been a bona fide Holder
        of a Security 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 a Board Resolution may remove the
Trustee, 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 and the appointment of a successor Trustee.

               (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,
the Company, by a Board Resolution, shall promptly appoint a successor Trustee.
If, within one year after such resignation, removal or incapability, or the
occurrence of such vacancy, a successor Trustee shall be appointed by Act of the
Holders of a majority in principal amount at Stated Maturity of the Outstanding
Securities 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 and supersede the successor Trustee appointed by the Company. If no
successor Trustee shall have been so appointed by the Company or the Holders and
accepted appointment in accordance with the applicable requirements of Section
611, 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 appointment of a successor Trustee.

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


SECTION 611.  Acceptance of Appointment by Successor.

               Every successor Trustee appointed hereunder 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 

<PAGE>   70

and money held by such retiring Trustee hereunder. 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.

               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 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 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 which
shall be authorized to act on behalf of the Trustee to authenticate Securities
issued upon original issue and upon exchange, registration of transfer or
partial redemption or partial purchase or pursuant to Section 308, 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 

<PAGE>   71

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.

               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 as their names
and addresses appear in the Security Register. 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 Company agrees to pay to each Authenticating Agent from time
to time reasonable compensation for its services under this Section.

               If an appointment is made pursuant to this Section, the
Securities may have endorsed thereon, in addition to the Trustee's certificate
of authentication, an alternative certificate of authentication in the following
form:

               This is one of the Securities described in the within-mentioned
Indenture.

Dated:

                                            Harris Trust and Savings Bank,
                                            as Trustee


<PAGE>   72

                                            By___________________________,
                                               As Authenticating Agent


                                            By___________________________
                                               Authorized Signatory



                                  ARTICLE SEVEN

                Holders' Lists and Reports by Trustee and 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 April 15 and
        October 15, commencing April 15, 1999, a list, in such form as the
        Trustee may reasonably require, of the names and addresses of the
        Holders 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 neither the Company nor the
Trustee nor any agent of either of them shall be held accountable by reason of
any disclosure of information as to the names and addresses of Holders made
pursuant to the Trust Indenture Act.

<PAGE>   73

SECTION 703.  Reports by Trustee.

               (a) Within 60 days after January 15 of each year commencing
January 15, 1999, 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 the Securities are listed, with the Commission and with the Company. The
Company will promptly notify the Trustee when the Securities are listed on any
stock exchange.


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; 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 shall be filed with the
Trustee within 15 days after the same is so required to be filed with the
Commission. The Trustee's receipt of such reports, information and documents
shall not constitute constructive notice of any information contained therein or
determinable from information contained therein.


                                  ARTICLE EIGHT

              Consolidation, Merger, Conveyance, Transfer or Lease

SECTION 801.  Company May Consolidate, Etc. Only on Certain Terms.

        The Company (x) shall not, in any transaction or series of related
transactions, merge or consolidate with or into, or sell, assign, convey,
transfer, lease or otherwise dispose of its properties and assets substantially
as an entirety to, any Person, and (y) shall not permit any of its Restricted
Subsidiaries to enter into any such transaction or series of transactions if
such transaction or series of transactions, in the aggregate, would result in a
sale, assignment, conveyance, transfer, lease or other disposition of the
properties and assets of the Company and its Restricted Subsidiaries, taken as a
whole, substantially as an entirety to any Person, unless, in each case (x) or
(y), at the time and after giving effect thereto

               (i) either: (A) if the transaction or series of transactions is a
        consolidation of the Company with or a merger of the Company with or
        into any other Person, the 


<PAGE>   74

        Company shall be the surviving Person of such merger or consolidation,
        or (B) the Person formed by any consolidation with or merger with or
        into the Company, or to which the properties and assets of the Company
        or the Company and its Restricted Subsidiaries, taken as a whole, as the
        case may be, substantially as an entirety are sold, assigned, conveyed,
        leased or otherwise transferred (any such surviving Person or transferee
        Person referred to in this clause (B) being the "Surviving Entity"),
        shall be a corporation, partnership or trust organized and existing
        under the laws of the United States of America, 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 the obligations of the Company under the Securities and
        this Indenture and, in each case, this Indenture, as so supplemented,
        shall remain in full force and effect, and

               (ii) immediately before and immediately after giving effect to
        such transaction or series of transactions on a pro forma basis
        (including any Debt Incurred or anticipated to be Incurred in connection
        with or in respect of such transaction or series of transactions), no
        Default or Event of Default shall have occurred and be continuing, and

               (iii) the Consolidated Net Worth of the Company or the Surviving
        Entity, as the case may be, shall be equal to or greater than that of
        the Company immediately prior to such transaction or series of
        transactions;

provided, however, that the foregoing requirements shall not apply to any
transaction or series of transactions involving the sale, assignment,
conveyance, transfer, lease or other disposition of the properties and assets by
any Restricted Subsidiary to any other Restricted Subsidiary, or the merger or
consolidation of any Restricted Subsidiary with or into any other Restricted
Subsidiary.

        In connection with any consolidation, merger, sale, assignment,
conveyance, transfer, lease or other disposition contemplated by the foregoing
provisions, the Company shall deliver, or cause to be delivered, to the Trustee,
in form and substance reasonably satisfactory to the Trustee, an Officers'
Certificate stating that such consolidation, merger, sale, assignment,
conveyance, transfer, lease or other disposition and the supplemental indenture
in respect thereof (required under clause (i)(B) of the preceding paragraph)
comply with the requirements of this Indenture and an Opinion of Counsel that
the conditions of this Article 8 have been complied with. Each such Officers'
Certificate shall set forth the manner of determination of the Consolidated Net
Worth in accordance with clause (iii) of the preceding paragraph.

        For all purposes of this Indenture and the Securities (including the
provisions described in the two immediately preceding paragraphs and Section
1008 and Section 1010), Subsidiaries of any Surviving Entity will, upon such
transaction or series of transactions, become Restricted Subsidiaries or
Unrestricted Subsidiaries as provided pursuant to Section 1010 and all Debt of
the Surviving Entity and its Subsidiaries that was not Debt of the Company and
its Subsidiaries immediately prior to such transaction or series of transactions
shall be deemed to have been Incurred upon such transaction or series of
transactions.
<PAGE>   75

SECTION 802.  Successor Substituted.

               Upon any transaction or series of transactions that are of the
type described in clause (x) or (y) of, and are effected in accordance with,
Section 801, the Surviving Entity 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 Surviving Entity 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 a 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
        herein and in the Securities; or

               (2) to add to the covenants of the Company for the benefit of the
        Holders, or to surrender any right or power herein conferred upon the
        Company; or

               (3) to comply with any requirements of the Commission in order to
        effect and maintain the qualification of this Indenture under the Trust
        Indenture Act; or

               (4) to cure any ambiguity, to correct or supplement any provision
        herein which may be defective or 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 such action pursuant to
        this Clause (5) shall not adversely affect the interests of the Holders
        in any material respect (as determined in good faith by the Board of
        Directors).


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,
the Company, when authorized by 

<PAGE>   76

a 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 of
modifying in any manner the rights of the Holders under this Indenture;
provided, however, that no such supplemental indenture shall, without the
consent of the Holder of each Outstanding Security affected thereby,

               (1) change the Stated Maturity 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 reduce the Default Amount that would be due and payable on
        acceleration of the Maturity thereof pursuant to Section 502, 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 Stated Maturity thereof (or, in the case of redemption, on or
        after the Redemption Date or, in the case of any Security required to be
        purchased pursuant to an Offer to Purchase, on or after the applicable
        Purchase Date), or

               (2) reduce the percentage in principal amount at Stated Maturity
        of the Outstanding Securities, 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 1018, 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 pursuant to Section 1013, modify the provisions of this
        Indenture with respect to such Offer to Purchase in a manner adverse to
        such Holder.

               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.


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.

<PAGE>   77

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.


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 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 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.


                                   ARTICLE TEN

                                    Covenants

SECTION 1001.  Payment of Principal, Premium and Interest.

               The Company will duly and punctually pay the principal of (and
premium, if any) and interest on the Securities 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, an office or agency where Securities may be presented or
surrendered for payment, where Securities may be surrendered for registration of
transfer or exchange and where notices and demands to or upon the Company in
respect of the Securities 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 

<PAGE>   78

Office of the Trustee, and the Company hereby appoints the Trustee as its agent
to receive all such presentations, surrenders, notices and demands. In the event
any such notice or demands are so made or served on the Trustee, the Trustee
will promptly forward copies thereof to the Company.

               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) where the Securities may be presented or surrendered for any or all
such purposes and may from time to time rescind such designations; provided,
however, that no such designation or rescission shall in any manner relieve the
Company of its obligation to maintain an office or agency in the Borough of
Manhattan, The City of New York, for such purposes. The Company 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.


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

               If the Company shall at any time act as its own Paying Agent, it
will, on or before each due date of the principal of (and premium, if any) or
interest on any of the Securities, 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 of its action or failure so to act.

               Whenever the Company shall have one or more Paying Agents, it
will, prior to each due date of the principal of (and premium, if any) or
interest on any Securities, 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 as provided by the Trust Indenture Act, and (unless such Paying Agent is
the Trustee) the Company will promptly notify the Trustee of its action or
failure so to act.

               The Company will cause each Paying Agent 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: (i) comply with the provisions of the Trust Indenture
Act applicable to it as Paying Agent and (ii) during the continuance of any
default by the Company (or any other obligor upon the Securities) in the making
of any payment in respect of the Securities, upon the written request of the
Trustee, forthwith pay to the Trustee all sums held in trust by such Paying
Agent as such.

               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 

<PAGE>   79

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.

               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 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 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 City of 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 material franchises; provided,
however, that the Company shall not be required to preserve any such right or
franchise if the Board of Directors in good faith 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 material properties used or useful in
the conduct of its business or the business of any Restricted Subsidiary 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 material properties if
such discontinuance is, as determined by the Board of Directors in good faith,
desirable in the conduct of its business or the business of any Restricted
Subsidiary and not disadvantageous in any material respect to the Holders.


SECTION 1006.  Payment of Taxes and Other Claims.
<PAGE>   80

               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 of its
Restricted Subsidiaries or upon the income, profits or property of the Company
or any of its Restricted Subsidiaries, and (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 of its Restricted Subsidiaries; 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.  Maintenance of Insurance.

               The Company shall, and shall cause its Restricted Subsidiaries
to, keep at all times all of their properties which are of an insurable nature
insured against loss or damage with insurers believed by the Company to be
responsible to the extent that property of similar character is usually so
insured by corporations similarly situated and owning like properties in
accordance with good business practice. The Company shall, and shall cause its
Restricted Subsidiaries to, use the proceeds from any such insurance policy to
repair, replace or otherwise restore all material properties to which such
proceeds relate, provided, however, that the Company shall not be required to
repair, replace or otherwise restore any such material property if the Board of
Directors in good faith determines that such inaction is desirable in the
conduct of the business of the Company or any Restricted Subsidiary and not
disadvantageous in any material respect to the Holders.


SECTION 1008.  Limitation on Consolidated Debt.

        The Company shall not, and shall not permit any Restricted Subsidiary
to, Incur any Debt (including Acquired Debt), other than Permitted Debt, unless
(i) with respect to Debt Incurred under this clause (i), the Debt so Incurred
and outstanding is in an aggregate principal amount that does not exceed 2.25
times, with respect to Capital Stock sales after June 1, 1997 and on or prior to
March 31, 1998, or 2.00 times, with respect to Capital Stock sales after March
31, 1998, the aggregate amount of net cash proceeds (or 80% of the Fair Market
Value of property other than cash) received by the Company after June 1, 1997
from the issuance and sale (other than to a Restricted Subsidiary) of shares of
its Capital Stock (other than Redeemable Stock), or any options, warrants or
other rights to purchase such Capital Stock (other than Redeemable Stock), other
than (x) proceeds applied for use as a Directed Investment (unless such
designation has been revoked by the Board of Directors and the Company either
abandons its plans to make such Investment or is able to make such Investment
pursuant to Section 1009 (other than as a Directed Investment)) and (y) proceeds
which have been included in the computation of the amounts available for
Restricted Payments pursuant to clause (c)(2) of Section 1009, to the extent the
inclusion thereof was necessary to allow a subsequent Restricted Payment to be
made, or (ii) on 

<PAGE>   81

the date of such Incurrence, after giving effect to the Incurrence of such Debt
(or Acquired Debt) and the receipt and application of the net proceeds thereof
(and, if the net proceeds of such new Debt are used to acquire a Person that
becomes a Restricted Subsidiary or an operating business of the Company or a
Restricted Subsidiary, to all terms of such acquisition) on a pro forma basis,
the Operating Cash Flow to Consolidated Interest Expense Ratio would equal or
exceed 1.75 to 1.


SECTION 1009.  Limitation on Restricted Payments.

        The Company shall not, directly or indirectly:

               (i) declare or pay any dividend on, or make any distribution to
        the holders of, any shares of its Capital Stock (other than dividends or
        distributions payable solely in its Capital Stock (other than Redeemable
        Stock) or in options, warrants or other rights to purchase any such
        Capital Stock (other than Redeemable Stock));

               (ii) purchase, redeem or otherwise acquire or retire for value,
        or permit any Restricted Subsidiary to, directly or indirectly,
        purchase, redeem or otherwise acquire or retire for value (other than
        value consisting solely of Capital Stock of the Company that is not
        Redeemable Stock or options, warrants or other rights to acquire such
        Capital Stock that is not Redeemable Stock), any Capital Stock of the
        Company (including options, warrants or other rights to acquire such
        Capital Stock);

               (iii) redeem, repurchase, defease or otherwise acquire or retire
        for value, or permit any Restricted Subsidiary to, directly or
        indirectly, redeem, repurchase, defease or otherwise acquire or retire
        for value (other than value consisting solely of Capital Stock of the
        Company that is not Redeemable Stock or options, warrants or other
        rights to acquire such Capital Stock that is not Redeemable Stock),
        prior to any scheduled maturity, scheduled repayment or scheduled
        sinking fund payment, any Debt that is subordinate (whether pursuant to
        its terms or by operation of law) in right of payment to the Securities;
        or

               (iv) make, or permit any Restricted Subsidiary, directly or
        indirectly, to make, any Investment (other than any Permitted
        Investment) in any Person (other than in a Restricted Subsidiary or a
        Person that becomes a Restricted Subsidiary as a result of such
        Investment);

(each of the foregoing actions set forth in clauses (i) through (iv), other than
any such action that is a Permitted Investment or a Permitted Distribution,
being referred to as a "Restricted Payment") unless, at the time of such
Restricted Payment, and after giving effect thereto:

               (a) no Default or Event of Default shall have occurred and be
        continuing;

               (b) except with respect to Investments, after giving effect, on a
        pro forma basis, to such Restricted Payment and the Incurrence of any
        Debt the net proceeds of which are 

<PAGE>   82

        used to finance such Restricted Payment, the Consolidated Debt to
        Annualized Operating Cash Flow Ratio would not have exceeded 7.0 to 1;
        and

               (c) after giving effect to such Restricted Payment on a pro forma
        basis, the aggregate amount of all Restricted Payments made on or after
        February 15, 1994 shall not exceed:

                      (1) 50% of the Consolidated Net Income (or, in the case of
               a Consolidated Net Loss, minus 100% of such deficit) of the
               Company for the period (taken as one accounting period) from
               April 1, 1994 to the last day of the last fiscal quarter
               preceding the date of the proposed Restricted Payment, plus

                      (2) the aggregate net proceeds, including the fair market
               value of property other than cash (as determined by the Board of
               Directors, whose good faith determination shall be conclusive and
               evidenced by a Board Resolution), received by the Company from
               the issuance and sale (other than to a Restricted Subsidiary) on
               or after February 15, 1994 of shares of its Capital Stock (other
               than Redeemable Stock), or any options, warrants or other rights
               to purchase such Capital Stock (other than Redeemable Stock),
               other than (x) (except for purposes of determining whether an
               Investment under clause (iv) above is permitted) shares of
               Capital Stock or options, warrants or other rights to purchase
               Capital Stock (or shares issuable upon exercise thereof) issued
               or sold in the PowerFone Merger, Questar/AMI Share Exchanges,
               Motorola Business Acquisition and NTT transactions as defined and
               described in the Company's prospectus, dated February 9, 1994,
               relating to the Company's Senior Redeemable Discount Notes due
               2004 and (y) shares of Capital Stock or options, warrants or
               other rights to purchase Capital Stock (or shares issuable upon
               exercise thereof), the proceeds of the issuance of which is used
               (A) to make a Directed Investment (unless such designation has
               been revoked by the Board of Directors and the Company is able
               to make such Investment pursuant to this Section 1009 (other than
               as a Directed Investment)) or (B) to Incur Debt under clause (i)
               of Section 1008 (unless and until the amount of any such Debt (I)
               is treated as newly issued Debt and could be Incurred in
               accordance with the Section 1008 (other than under clause (i)
               thereof) or (II) has been repaid or refinanced with the proceeds
               of Debt Incurred in accordance with Section 1008 (other than
               under clause (i) thereof) or (III) has otherwise been repaid),
               plus

                      (3) the aggregate net proceeds, including the fair market
               value of property other than cash (as determined by the Board of
               Directors, whose good faith determination shall be conclusive and
               evidenced by a Board Resolution), received by the Company from
               the issuance or sale (other than to a Restricted Subsidiary)
               after February 15, 1994 of any Capital Stock of the Company
               (other than Redeemable Stock), or any options, warrants or other
               rights to purchase such Capital Stock (other than Redeemable
               Stock), upon the conversion of, or exchange for, Debt of the
               Company or a Restricted Subsidiary.
<PAGE>   83

        The foregoing limitations in this Section 1009 do not limit or restrict
the making of any Permitted Distribution, Permitted Investment or Directed
Investment, and none of a Permitted Distribution, Permitted Investment or
Directed Investment shall be counted as a Restricted Payment for purposes of
clause (c) above. In addition, the foregoing limitations do not prevent the
Company from (I) paying a dividend on Capital Stock of the Company within 60
days after the declaration thereof if, on the date when the dividend was
declared, the Company could have paid such dividend in accordance with the
provisions of this Indenture, (II) repurchasing Capital Stock of the Company
(including options, warrants or other rights to acquire such Capital Stock) from
employees or former employees of the Company or any Subsidiary thereof for
consideration not to exceed $500,000 in the aggregate in any fiscal year (with
repurchases pursuant to this clause (II) not being counted as Restricted
Payments for purposes of clause (c) above) or (III) the repurchase, redemption
or other acquisition for value of Capital Stock of the Company to the extent
necessary to prevent the loss or secure the renewal or reinstatement of any
license or franchise held by the Company or any of its Subsidiaries from any
governmental agency; or (IV) Investments in Unrestricted Subsidiary Funding
Company so long as (x) such Investments are invested in Nextel International,
Inc. and (y) Nextel International, Inc. is a Subsidiary of the Company.

        Notwithstanding the foregoing limitations in this Section 1009, the
Company will be permitted to make any Investment in a Person that is not (either
before or after giving effect thereto) a Subsidiary of the Company, provided
that, immediately after giving effect thereto, the amount equal to (a) the
aggregate amount of all Investments made pursuant to this paragraph minus (b)
all cash received by the Company or any Restricted Subsidiary from the sale,
transfer or other disposition to a Person that is not a Subsidiary of the
Company of any such Investment (or portion thereof) included in such aggregate
amount (with the amount of cash to be counted for this purpose not to exceed the
amount of such Investment (or portion thereof) so included), shall not exceed
the greater of (i) $250 million and (ii) 2% of the Total Market Value of Equity
of the Company as of such time. For purposes of determining the aggregate amount
of Investments referred to in clause (a), the amount of any Investment shall be
deemed to equal the cash portion thereof plus the fair market value of any
non-cash portion thereof (to the extent such portion constitutes an Investment)
at the time such Investment is made, as determined by the Board of Directors
(whose good faith determination shall be conclusive and evidenced by a Board
Resolution).

        Notwithstanding the foregoing, no Investment in a Person that
immediately thereafter would be a Restricted Subsidiary will be a Restricted
Payment. In addition, if any Person in which an Investment is made, which
Investment constitutes a Restricted Payment when made, thereafter becomes a
Restricted Subsidiary, all such Investments previously made in such Person shall
no longer be counted as Restricted Payments for purposes of calculating the
aggregate amount of Restricted Payments pursuant to clause (c) of the third
preceding paragraph or the aggregate amount of Investments pursuant to clause
(a) of the immediately preceding paragraph, in each case to the extent such
Investments would otherwise be so counted.
<PAGE>   84

        For purposes of clause (c)(3) above, the net proceeds received by the
Company from the issuance or sale of its Capital Stock either upon the
conversion of, or exchange for, Debt of the Company or any Restricted Subsidiary
shall be deemed to be an amount equal to (a) the sum of (i) the principal amount
or accreted value (whichever is less) of such Debt on the date of such
conversion or exchange and (ii) the additional cash consideration, if any,
received by the Company upon such conversion or exchange, less any payment on
account of fractional shares, minus (b) all expenses incurred in connection with
such issuance or sale. In addition, for purposes of clause (c)(3) above, the net
proceeds received by the Company from the issuance or sale of its Capital Stock
upon the exercise of any options or warrants of the Company or any Restricted
Subsidiary shall be deemed to be an amount equal to (a) the additional cash
consideration, if any, received by the Company upon such exercise, minus (b) all
expenses incurred in connection with such issuance or sale.

        For purposes of this Section 1009, if a particular Restricted Payment
involves a non-cash payment, including a distribution of assets, then such
Restricted Payment shall be deemed to be an amount equal to the cash portion of
such Restricted Payment, if any, plus an amount equal to the fair market value
of the non-cash portion of such Restricted Payment, as determined by the Board
of Directors (whose good faith determination shall be conclusive and evidenced
by a Board Resolution).


SECTION 1010.  Restricted Subsidiaries.

        The Company shall not designate any Restricted Subsidiary as an
Unrestricted Subsidiary, and shall not itself, and shall not permit any
Restricted Subsidiary to, sell, convey, transfer or otherwise dispose of any
assets, other than in the ordinary course of business, to any Unrestricted
Subsidiary or any Person that becomes an Unrestricted Subsidiary as part of such
transaction, unless, after giving effect to any such action, the assets (not
including any assets so sold, conveyed, transferred or otherwise disposed of,
other than in the ordinary course of business, to any Unrestricted Subsidiary or
any Person that becomes an Unrestricted Subsidiary as part of such transaction)
and business of the Company and its remaining Restricted Subsidiaries generated
at least 90% of Digital Mobile-SMR Operating Cash Flow in the fiscal quarter of
the Company most recently completed prior to the date of such action.

        The Board of Directors may designate any existing Unrestricted
Subsidiary or any Person that is about to become a Subsidiary of the Company as
a Restricted Subsidiary if, after giving effect to such action (and, if such
designation is made in connection with the acquisition of a Person or an
operating business that is about to become a Subsidiary of the Company, after
giving effect to all terms of such acquisition) on a pro forma basis, on the
date of such action, the Debt, if any, of such Unrestricted Subsidiary or Person
outstanding immediately prior to such designation would have been permitted to
be Incurred (and shall be deemed to have been Incurred) for all purposes of this
Indenture.

        Subject to the second preceding paragraph and compliance with Section
1009, the Board of Directors may designate any Restricted Subsidiary as an
Unrestricted Subsidiary.
<PAGE>   85

        The designation by the Board of Directors of a Restricted Subsidiary as
an Unrestricted Subsidiary shall, for all purposes of Section 1009 (including
clause (b) thereof), be deemed to be a Restricted Payment of an amount equal to
the fair market value of the Company's ownership interest in such Subsidiary
(including, without duplication, such indirect ownership interest in all
Subsidiaries of such Subsidiary), as determined by the Board of Directors in
good faith and evidenced by a Board Resolution.

        Notwithstanding the foregoing provisions of this Section 1010, the Board
of Directors may not designate a Subsidiary of the Company to be an Unrestricted
Subsidiary if, after such designation, (a) the Company or any of its other
Restricted Subsidiaries (i) provides credit support for, or a Guarantee of, any
Debt of such Subsidiary (including any undertaking, agreement or instrument
evidencing such Debt) or (ii) is directly or indirectly liable for any Debt of
such Subsidiary, (b) a default with respect to any Debt of such Subsidiary
(including any right which the holders thereof may have to take enforcement
action against such Subsidiary) would permit (upon notice, lapse of time or
both) any holder of any other Debt of the Company or any Restricted Subsidiary
to declare a default on such other Debt or cause the payment thereof to be
accelerated or payable prior to its final scheduled maturity or (c) such
Subsidiary owns any Capital Stock of, or owns or holds any Lien on any property
of, any Restricted Subsidiary which is not a Subsidiary of the Subsidiary to be
so designated.

        The Board of Directors, from time to time, may designate any Person that
is about to become a Subsidiary of the Company as an Unrestricted Subsidiary,
and may designate any newly-created Subsidiary as an Unrestricted Subsidiary, if
at the time such Subsidiary is created it contains no assets (other than such de
minimis amount of assets then required by law for the formation of corporations)
and no Debt. Subsidiaries of the Company that are not designated by the Board of
Directors as Restricted or Unrestricted Subsidiaries shall be deemed to be
Restricted Subsidiaries. Notwithstanding any provisions of this Section 1010,
all Subsidiaries of an Unrestricted Subsidiary shall be Unrestricted
Subsidiaries. The Board of Directors shall not change the designation of a
Subsidiary of the Company more than twice in any period of five years.


SECTION 1011.  Transactions with Affiliates.

        The Company shall not, and shall not permit any Restricted Subsidiary
to, directly or indirectly, enter into any transaction (including the purchase,
sale, lease or exchange of any property or the rendering of any service) or
series of related transactions with any Affiliate of the Company on terms that
are less favorable to the Company or such Restricted Subsidiary, as the case may
be, than those which might be obtained at the time of such transaction from a
Person that is not such an Affiliate; provided, however, that this Section 1011
shall not limit, or be applicable to, (i) any transaction between Unrestricted
Subsidiaries not involving the Company or any Restricted Subsidiary, (ii) any
transaction between the Company and any Restricted Subsidiary or between
Restricted Subsidiaries or (iii) any Permitted Transactions. In addition, any
transaction or series of related transactions, other than Permitted
Transactions, between the Company or any Restricted Subsidiary and any Affiliate
of the Company (other than a Restricted Subsidiary) involving an aggregate
consideration of $5 million or more must be approved in 

<PAGE>   86

good faith by a majority of the Company's Disinterested Directors (of which
there must be at least one) and evidenced by a Board Resolution. For purposes of
this Section 1011, any transaction or series of related transactions between the
Company or any Restricted Subsidiary and an Affiliate of the Company that is
approved by a majority of the Disinterested Directors (of which there must be at
least one) and evidenced by a Board Resolution shall be deemed to be on terms as
favorable as those that might be obtained at the time of such transaction (or
series of transactions) from a Person that is not such an Affiliate and thus
shall be permitted under this Section 1011.


SECTION 1012.  [Intentionally Omitted]


SECTION 1013.  Change of Control.

        Upon the occurrence of a Change of Control, the Company shall be
required to make an Offer to Purchase Outstanding Securities at a purchase price
in cash equal to 101% of the principal amount thereof, plus accrued and unpaid
interest, if any, to the relevant Purchase Date. The Offer to Purchase must be
made within 30 days following a Change of Control, must remain open for at least
30 and not more than 60 days and must comply with the requirements of Rule 14e-1
under the Exchange Act and any other applicable securities laws and regulations.


SECTION 1014.  [Intentionally Omitted]


SECTION 1015.  Activities of the Company and Restricted Subsidiaries.

        The Company shall not, and shall not permit any Restricted Subsidiary
to, engage in any business other than the telecommunications business and
related activities and services, including such businesses, activities and
services as the Company and the Restricted Subsidiaries are engaged in on the
Closing Date.


SECTION 1016.  Provision of Financial Information.

        Whether or not the Company is subject to Section 13(a) or 15(d) of the
Exchange Act, or any successor provision thereto, the Company shall file with
the Commission the annual reports, quarterly reports and other documents which
the Company would have been required to file with the Commission pursuant to
such Section 13(a) or 15(d) or any successor provision thereto if the Company
were subject thereto, such documents to be filed with the Commission on or prior
to the respective dates (the "Required Filing Dates") by which the Company would
have been required to file them. The Company shall also in any event (a) within
15 days of each Required 

<PAGE>   87

Filing Date (i) transmit by mail to all Holders, as their names and addresses
appear in the Security Register, without cost to such Holders, and (ii) file
with the Trustee copies of the annual reports, quarterly reports and other
documents which the Company would have been required to file with the Commission
pursuant to Section 13(a) or 15(d) of the Exchange Act or any successor
provisions thereto if the Company were subject thereto and (b) if filing such
documents by the Company with the Commission is not permitted under the Exchange
Act, promptly upon written request supply copies of such documents to any
prospective Holder. The Trustee's receipt of such reports, information and
documents shall not constitute constructive notice of any information contained
therein or determinable from information contained therein.


SECTION 1017.  Statement by Officers as to Default; Compliance Certificates.

               (a) The Company shall deliver to the Trustee, within 120 days
after the end 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 (without regard to
any period of grace or requirement of notice provided hereunder), 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 1018.  Waiver of Certain Covenants.

               The Company may omit in any particular instance to comply with
any covenant or condition set forth in Section 801, provided pursuant to Section
901(2) and set forth in Sections 1004 to 1016, inclusive, if before the time for
such compliance the Holders of at least a majority in principal amount at Stated
Maturity of the Outstanding Securities shall, by Act of such Holders, 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; provided, however, with respect to an Offer to Purchase as to
which an Offer has been mailed, no such waiver may be made or shall be effective
against any Holder tendering Securities pursuant to such Offer, and the Company
may not omit to comply with the terms of such Offer as to such Holder.


                                 ARTICLE ELEVEN

                            Redemption of Securities


<PAGE>   88

SECTION 1101.  Right of Redemption.

               The Securities may be redeemed at any time on or after November
1, 2003, at the Company's option, in whole or in part, upon not less than 30 or
more than 60 days' prior written notice mailed by first class mail to each
Holder's last address as it appears in the Security Register, at the redemption
prices (expressed as a percentage of the principal amount thereof) set forth
below, plus an amount in cash equal to all accrued and unpaid interest to the
Redemption Date, if redeemed during the 12-month period beginning November 1 of
each of the years set forth below.
<TABLE>
<CAPTION>

                   YEAR                         PERCENTAGE
                   ----                         ----------
<S>                                             <C>     
                   2003                          106.000%
                   2004                          104.800%
                   2005                          103.600%
                   2006                          102.400%
                   2007                          101.200%
                   2008                          100.000%
</TABLE>

               Interest installments whose Stated Maturity is on or prior to any
Redemption Date will be payable to the Holders of Securities, or one or more
Predecessor Securities, of record at the close of business on the relevant
Record Dates for the payment of such interest installments.

               In addition to any redemption provided for in the immediately
preceding paragraphs, in the event of a sale by the Company after the Closing
Date and on or prior to November 1, 2001 of its Capital Stock (other than
Redeemable Stock) in a single transaction or series of transactions for an
aggregate purchase price equal to or exceeding $50 million, up to a maximum of
35% of the original aggregate principal amount of the Outstanding Securities
will, within 180 days of such sale, at the option of the Company, upon not less
than 30 nor more than 60 days' notice by mail, be redeemable from the net
proceeds thereof (but only to the extent such proceeds consist of cash or
readily marketable cash equivalents received in respect of the Company's Capital
Stock so sold, in each case net of all commissions, discounts, fees, expenses
and taxes incurred in respect thereof) at a Redemption Price equal to 112% of
the principal amount of the Securities to be redeemed plus accrued and unpaid
interest to the Redemption Date.


SECTION 1102.  Applicability of Article.

               Redemption of Securities at the election of the Company, as
permitted by this Indenture and the provisions of the Securities, shall be made
in accordance with such provisions and this Article.


SECTION 1103.  Election to Redeem; Notice to Trustee.

               The election of the Company to redeem any Securities pursuant to
Section 1101 


<PAGE>   89

shall be evidenced by a Board Resolution. In case of any redemption at the
election of the Company pursuant to Section 1101, 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 and of the principal amount of Securities to be redeemed.


SECTION 1104.  Selection by Trustee of Securities to Be Redeemed.

               In the case of any partial redemption, selection of the
Securities for redemption will be made by the Trustee in compliance with the
requirements of the principal national securities exchange, if any, on which the
Securities are listed or, if the Securities are not listed on a national
securities exchange, on a pro rata basis, by lot or by such other method as the
Trustee in its sole discretion shall deem to be fair and appropriate; provided
that no Security of $1,000 in principal amount or less shall be redeemed in
part.

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

               For all purposes of this Indenture and of the Securities, 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 1105.  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 his address appearing in
the Security Register.

               All notices of redemption shall state (including CUSIP, CINS and
ISIN numbers, if any):

               (1) the Redemption Date,

               (2) the Redemption Price,

               (3) if less than all the Outstanding Securities are to be
        redeemed, the identification (and, in the case of partial redemption,
        the principal amounts) of the particular Securities to be redeemed,
        including CUSIP, CINS and ISIN numbers,

               (4) that on the Redemption Date the Redemption Price will become
        due and 

<PAGE>   90

        payable upon each such Security to be redeemed and that cash interest
        thereon will cease to accrue on and after said Redemption Date,

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

               (6) if the redemption is being made pursuant to the provisions of
        the Securities set forth in the third paragraph of Section 203, a brief
        description of the nature and amount of Capital Stock sold by the
        Company, the aggregate purchase price thereof and the net cash proceeds
        therefrom available for such redemption, the date or dates on which such
        sale was completed and the percentage of the aggregate principal amount
        of Outstanding Securities being redeemed.

               Notice of redemption of Securities to be redeemed at the election
of the Company shall be given by the Company or, at the Company's request, by
the Trustee in the name and at the expense of the Company and shall be
irrevocable.


SECTION 1106.  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) any applicable accrued interest on, all
the Securities which are to be redeemed on that date.


SECTION 1107.  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 any
applicable accrued interest) such Securities shall not 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 any applicable accrued and unpaid interest to the Redemption Date;
provided, however, that installments of interest whose Stated Maturity is on or
prior to the Redemption Date shall 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 309.

               If any Security called for redemption in accordance with the
election of the Company made pursuant to Section 1101 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.

<PAGE>   91

SECTION 1108.  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 any authorized denomination as
requested by such Holder, in aggregate principal amount at Stated Maturity equal
to and in exchange for the unredeemed portion of the principal amount at Stated
Maturity of the Security so surrendered.


                                 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 the Outstanding Securities (as a whole and not
in part) upon compliance with the conditions set forth below in this Article.
Any such election shall be evidenced by a Board Resolution.


SECTION 1202.  Defeasance and Discharge.

               Upon the Company's exercise of its option to have this Section
applied to the Outstanding Securities (as a whole and not in part), the Company
shall be deemed to have been discharged from its obligations with respect to
such Securities as provided in this Section on and after the date the conditions
set forth in Section 1204 are satisfied (hereinafter called "Defeasance"), and
thereafter such Securities shall not be subject to redemption pursuant thereto.
For this purpose, such Defeasance means that the Company shall be deemed to have
paid and discharged the entire indebtedness represented by such Securities 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), subject to the following which shall survive until otherwise terminated
or discharged hereunder: (1) the rights of Holders of such Securities 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 any
premium and interest on such Securities when payments are due, (2) the Company's
obligations with respect to such Securities under Sections 304, 305, 308, 1002
and 1003, (3) the rights, powers, trusts, duties and immunities of the Trustee
hereunder and 

<PAGE>   92

(4) this Article. Subject to compliance with this Article, the Company may
exercise its option to have this Section applied to the Outstanding Securities
(as a whole and not in part) notwithstanding the prior exercise of its option to
have Section 1203 applied to such Securities.


SECTION 1203.  Covenant Defeasance.

               Upon the Company's exercise of its option to have this Section
applied to the Outstanding Securities (as a whole and not in part), (1) the
Company shall be released from its obligations under Section 801(iii), Sections
1005 through 1016, inclusive, and any covenant provided pursuant to Section
901(2) and (2) the occurrence of any event specified in Section 501(4) (with
respect to Section 801(iii)), Section 501(5) (with respect to any of Sections
1005 through 1016, inclusive, and any such covenants provided pursuant to
Section 901(2)), Section 501(6) or Section 501(7) shall be deemed not to be or
result in an Event of Default, in each case with respect to such Securities as
provided in this Section on and after the date the conditions set forth in
Section 1204 are satisfied (hereinafter called "Covenant Defeasance"). For this
purpose, such Covenant Defeasance means that, with respect to such Securities,
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 specified Section (to
the extent so specified in the case of Sections 501(4) and 501(5)), whether
directly or indirectly by reason of any reference elsewhere herein to any such
Section or by reason of any reference in any such Section 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 the application of
Section 1202 or Section 1203 to the Outstanding Securities:

               (1) The Company shall irrevocably have deposited or caused to be
        deposited with the Trustee (or another trustee which satisfies the
        requirements contemplated by Section 609 and agrees to comply with the
        provisions of this Article applicable to it) as trust funds in trust for
        the purpose of making the following payments, specifically pledged as
        security for, and dedicated solely to, the benefits 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, in each case sufficient, in the
        opinion of a nationally recognized firm of independent public
        accountants expressed in a written certification thereof delivered to
        the Trustee, to pay and discharge, and which shall be applied by the
        Trustee (or any such other qualifying trustee) to pay and discharge, the
        principal of and any installment of interest on such Securities on the
        respective Stated Maturities thereof, in accordance with the terms of
        this Indenture and such Securities. As used herein, "U.S. Government
        Obligation" means (x) any security which is (i) a direct obligation of
        the United States of America for the payment of which the full faith and


<PAGE>   93

        credit of the United States of America is pledged or (ii) an obligation
        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 (i) or (ii), is not
        callable or redeemable at the option of the issuer thereof, and (y) any
        depository receipt issued by a bank (as defined in Section 3(a)(2) of
        the Securities Act) as custodian with respect to any U.S. Government
        Obligation which is specified in Clause (x) above and held by such bank
        for the account of the holder of such depository receipt, or with
        respect to any specific payment of principal of or interest on any U.S.
        Government Obligation which is so specified and held, 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 depository
        receipt from any amount received by the custodian in respect of the U.S.
        Government Obligation or the specific payment of principal or interest
        evidenced by such depository receipt.

               (2) In the event of an election to have Section 1202 apply to the
        Outstanding Securities, the Company shall have delivered to the Trustee
        an Opinion of Counsel stating that (A) the Company has received from, or
        there has been published by, the Internal Revenue Service a ruling or
        (B) since the Closing Date there has been a change in the applicable
        Federal income tax law, in either case (A) or (B) to the effect that,
        and based thereon such opinion shall confirm that, the Holders of such
        Securities will not recognize gain or loss for Federal income tax
        purposes as a result of the deposit, Defeasance and discharge to be
        effected with respect to such Securities and will be subject to Federal
        income tax on the same amount, in the same manner and at the same times
        as would be the case if such deposit, Defeasance and discharge were not
        to occur.

               (3) In the event of an election to have Section 1203 apply to the
        Outstanding Securities, the Company shall have delivered to the Trustee
        an Opinion of Counsel to the effect that the Holders of such Securities
        will not recognize gain or loss for Federal income tax purposes as a
        result of the deposit and Covenant Defeasance to be effected with
        respect to such Securities and will be subject to Federal income tax on
        the same amount, in the same manner and at the same times as would be
        the case if such deposit and Covenant Defeasance were not to occur.

               (4) No Default with respect to the Outstanding Securities shall
        have occurred and be continuing at the time of such deposit or, with
        regard to any such event specified in Sections 501(8) and (9), at any
        time on or prior to the 90th day after the date of such deposit (it
        being understood that this condition shall not be deemed satisfied until
        after such 90th day).

               (5) Such Defeasance or Covenant Defeasance shall not cause the
        Trustee to have a conflicting interest within the meaning of the Trust
        Indenture Act (assuming all Securities are in default within the meaning
        of such Act).
<PAGE>   94

               (6) Such Defeasance or Covenant Defeasance shall not result in a
        breach or violation of, or constitute a default under, any other
        agreement or instrument to which the Company is a party or by which it
        is bound.

               (7) Such Defeasance or Covenant Defeasance shall not result in
        the trust arising from such deposit constituting an investment company
        within the meaning of the Investment Company Act unless such trust shall
        be registered under such Act or exempt from registration thereunder.

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


SECTION 1205.     Deposited Money and U.S. Government Obligations to Be Held in 
                  Trust; 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 (solely for purposes of
this Section and Section 1206, the Trustee and any such other trustee are
referred to collectively as the "Trustee") pursuant to Section 1204 in respect
of the Outstanding 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 such 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 any premium and interest, but money so held in trust 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 Outstanding Securities.

               Anything in this Article 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 which, in the opinion of a nationally recognized firm of
independent public accountants 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 the Defeasance or Covenant Defeasance, as
the case may be, with respect to the Outstanding Securities.


SECTION 1206.  Reinstatement.

               If the Trustee or the Paying Agent is unable to apply any money
in accordance 


<PAGE>   95

with this Article with respect to any Securities by reason of any order or
judgment of any court or governmental authority enjoining, restraining or
otherwise prohibiting such application, then the obligations under this
Indenture and such Securities from which the Company has been discharged or
released pursuant to Section 1202 or 1203 shall be revived and reinstated as
though no deposit had occurred pursuant to this Article with respect to such
Securities, until such time as the Trustee or Paying Agent is permitted to apply
all money held in trust pursuant to Section 1205 with respect to such Securities
in accordance with this Article; provided, however, that if the Company makes
any payment of principal of or any premium or interest on any such Security
following such reinstatement of its obligations, the Company shall be subrogated
to the rights (if any) of the Holders of such Securities to receive such payment
from the money so held in trust.

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

               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.

<PAGE>   96



               IN WITNESS WHEREOF, the parties hereto have caused this Indenture
to be duly executed, and their respective corporate seals to be hereunto affixed
and attested, all as of the day and year first above written.


                                         NEXTEL COMMUNICATIONS, INC.


                                         By:

                                         Title:

Attest:




                                         HARRIS TRUST AND SAVINGS BANK, Trustee


                                         By:

                                         Title:

Attest:




<PAGE>   97



                                                                       EXHIBIT A
                                                                       ---------

                            Form of Certificate to Be
                          Delivered in Connection with
                       Transfers Pursuant to Regulation S

                                                          ---------------, -----

Harris Trust and Savings Bank
311 West Monroe Street
12th Floor
Chicago, Illinois  60606

Nextel Communications, Inc.
1505 Farm Credit Drive
McLean, Virginia 22102
Attn:  Treasurer

           Re: Nextel Communications, Inc. (the "Company")
               12% Senior Serial Redeemable Notes Due 2008 (the "Notes")

Dear Sirs:

               This letter relates to U.S. $__________ principal amount of Notes
represented by a Note (the "Legended Note") which bears a legend outlining
restrictions upon transfer of such Legended Note. Pursuant to Section 2.02 of
the Indenture dated as of November 4, 1998 (the "Indenture") relating to the
Notes, we hereby certify that we are (or we will hold such securities on behalf
of) a person outside the United States to whom the Notes could be transferred in
accordance with Rule 904 of Regulation S promulgated under the U.S. Securities
Act of 1933, as amended. Accordingly, you are hereby requested to exchange the
legended certificate for an unlegended certificate representing an identical
principal amount of Notes, all in the manner provided for in the Indenture.

               You and the Company are entitled to rely upon this letter and are
irrevocably authorized to produce this letter or a copy hereof to any interested
party in any administrative or legal proceedings or official inquiry with
respect to the matters covered hereby. Terms used in this certificate have the
meanings set forth in Regulation S.

                                Very truly yours,

                                [Name of Holder]


                                            By:
                                               Authorized Signature
<PAGE>   98

                                                                       EXHIBIT B
                                                                       ---------

                       Form of Certificate to Be Delivered
                         in Connection with Transfers to
                   Non-QIB Institutional Accredited Investors

                                                             ------------, -----


Harris Trust and Savings Bank
311 West Monroe Street
12th Floor
Chicago, Illinois  60606

Nextel Communications, Inc.
1505 Farm Credit Drive
McLean, Virginia  22102
Attn:  Treasurer

        Re:    Nextel Communications, Inc. (the "Company")
               12% Senior Serial Redeemable Notes due 2008 (the "Notes")

Dear Sirs:

               In connection with our proposed purchase of U.S.$__________
aggregate principal amount at stated maturity of the Notes, we confirm that:

               1. We understand that any subsequent transfer of the Notes is
subject to certain restrictions and conditions set forth in the Indenture dated
as of November 4, 1998 (the "Indenture"), relating to the Notes, and we agree to
be bound by, and not to resell, pledge or otherwise transfer the Notes except in
compliance with, such restrictions and conditions and the Securities Act of
1933, as amended (the "Securities Act").

               2. We understand that the offer and sale of the Notes have not
been registered under the Securities Act, and that the Notes may not be offered
or sold except as permitted in the following sentence. We agree, on our own
behalf and on behalf of any accounts for which we are acting as hereinafter
stated, that if we should offer or sell any Notes, we will do so only (A) to the
Company or any subsidiary thereof, (B) in accordance with Rule 144A under the
Securities Act to a "qualified institutional buyer" (as defined therein), (C) to
an institutional "accredited investor" (as defined below) that, prior to such
transfer, furnishes (or has furnished on its behalf by a U.S. broker-dealer) to
you and to the Company a signed letter substantially in the form of this letter,
(D) pursuant to the exemption from registration provided by Rule 144 under the
Securities Act, (E) pursuant to an effective registration statement under the
Securities 

<PAGE>   99

Act, if available, or (F) outside the United States in accordance with Rule 904
of Regulation S under the Securities Act, and we further agree to provide to any
person purchasing any of the Notes from us a notice advising such purchaser that
resales of the Notes are restricted as stated herein.

               3. We understand that, on any proposed resale of any Notes, we
will be required to furnish to you and the Company such certifications, legal
opinions and other information as you and the Company may reasonably require to
confirm that the proposed sale complies with the foregoing restrictions. We
further understand that the Notes purchased by us will bear a legend to the
foregoing effect.

               4. We are an institutional "accredited investor" (as defined in
Rule 501(a)(1), (2), (3) or (7) of Regulation D under the Securities Act) and
have such knowledge and experience in financial and business matters as to be
capable of evaluating the merits and risks of our investment in the notes, and
we and any accounts for which we are acting are each able to bear the economic
risk of our or its investment.

               5. We are acquiring the Notes purchased by us for our own account
or for one or more accounts (each of which is an institutional "accredited
investor") as to each of which we exercise sole investment discretion.

               You and the Company are entitled to rely upon this letter and are
irrevocably authorized to produce this letter or a copy hereof to any interested
party in any administrative or legal proceedings or official inquiry with
respect to the matters covered hereby.

                                Very truly yours,

                              [Name of Transferee]

                                       By:
                                           Authorized Signature



<PAGE>   100



                                                                       EXHIBIT C
                                                                       ---------

                       Form of Certificate to Be Delivered
                          in Connection with Transfers
                            Pursuant to Regulation S


                                                          ---------------, -----

Harris Trust and Savings Bank
311 West Monroe Street
12th Floor
Chicago, Illinois  60606

Nextel Communications, Inc.
1505 Farm Credit Drive
McLean, Virginia  22102
Attn:  Treasurer

        Re:    Nextel Communications, Inc. (the "Company")
               12% Senior Redeemable Notes due 2008 (the "Notes")

Dear Sirs:

               In connection with our proposed sale of U.S. $__________
aggregate principal amount of the Notes, we confirm that such sale has been
effected pursuant to and in accordance with Regulation S under the Securities
Act of 1933 and, accordingly, we represent that:

               (1) the offer of the Notes was not made to a person in the United
States;

               (2) at the time the buy order was originated, the transferee was
outside the United States or we and any person acting on our behalf reasonably
believed that the transferee was outside the United States;

               (3) no directed selling efforts have been made by us in the
United States in contravention of the requirements of Rule 903(b) or Rule 904(b)
of Regulation S, as applicable; and

               (4) the transaction is not part of a plan or scheme to evade the
registration requirements of the U.S. Securities Act of 1933.

               You and the Company are entitled to rely upon this letter and are
irrevocably authorized to produce this letter or a copy hereof to any interested
party in any administrative or 

<PAGE>   101

legal proceedings or official inquiry with respect to the matters covered
hereby. Terms used in this certificate have the meanings set forth in Regulation
S.

                                Very truly yours,

                                [Name of Transferor]



                                            By:
                                                   Authorized Signature


<PAGE>   102
<TABLE>
<CAPTION>

                                  TABLE OF CONTENTS

                                                                                          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
                    Agent Members............................................................2
                    Annualized Operating Cash Flow...........................................3
                    Authenticating Agent.....................................................3
                    Average Life.............................................................3
                    Beneficial Owner.........................................................3
                    Board of Directors.......................................................3
                    Board Resolution.........................................................3
                    Business Day.............................................................3
                    Capital Lease Obligations................................................3
                    Capital Stock............................................................4
                    Change of Control........................................................4
                    Closing Date.............................................................6
                    Closing Price............................................................6
                    Code ....................................................................6
                    Commission...............................................................6
                    Common Stock.............................................................7
                    Company..................................................................7
                    Company Request..........................................................7
                    Company Order............................................................7
                    Consolidated Adjusted Net Income.........................................7
                    Consolidated Adjusted Net Loss...........................................7
                    Consolidated Adjusted Net Income (Loss)..................................7
                    Consolidated Debt to Annualized Operating Cash Flow
                         Ratio...............................................................7
                    Consolidated Interest Expense............................................8
                    Consolidated Net Income..................................................8
                    Consolidated Net Loss....................................................8
                    Consolidated Net Income (Loss)...........................................8
                    Consolidated Net Worth...................................................8
                    Consolidation............................................................9
                    Corporate Trust Office...................................................9
</TABLE>

<PAGE>   103
<TABLE>

<S>                                                                                         <C>
                    Corporation..............................................................9
                    Covenant Defeasance......................................................9
                    Credit Facility..........................................................9
                    Debt ....................................................................9
                    Default.................................................................10
                    Default Amount..........................................................10
                    Defaulted Interest......................................................10
                    Defeasance..............................................................10
                    Depository..............................................................10
                    Digital Mobile..........................................................10
                    Digital Mobile-SMR Operating Cash Flow..................................10
                    Directed Investment.....................................................11
                    Disinterested Director..................................................11
                    Event of Default........................................................11
                    Exchange Securities.....................................................11
                    Exchange Act............................................................11
                    Expiration Date.........................................................11
                    Fair Market Value.......................................................12
                    FCC  ...................................................................12
                    February Indenture......................................................12
                    Global Securities.......................................................12
                    Guarantee...............................................................12
                    Holder..................................................................12
                    Incur...................................................................13
                    Indenture...............................................................13
                    Institutional Accredited Investor.......................................13
                    Interest Payment Date...................................................13
                    Investment..............................................................13
                    Investment Grade........................................................13
                    Licenses................................................................14
                    Lien ...................................................................14
                    Marketable Securities...................................................14
                    Maturity................................................................14
                    Memorandum..............................................................14
                    Moody's.................................................................14
                    Non-U.S. Person.........................................................15
                    Notice of Default.......................................................15
                    October Indenture.......................................................15
                    October Notes...........................................................15
                    Offer...................................................................15
                    Offer to Purchase.......................................................15
                    Officers' Certificate...................................................17
                    Offshore Global Securities..............................................17
</TABLE>

<PAGE>   104
<TABLE>

<S>                                                                                         <C>
                    Offshore Physical Securities............................................17
                    Operating Cash Flow.....................................................17
                    Operating Cash Flow to Consolidated Interest Expense
                         Ratio..............................................................17
                    Opinion of Counsel......................................................18
                    Outstanding.............................................................18
                    pari passu..............................................................18
                    Paying Agent............................................................19
                    Permitted Debt..........................................................19
                    Permitted Distribution..................................................20
                    Permitted Investment....................................................20
                    Permitted Transaction...................................................21
                    Person..................................................................21
                    Predecessor Security....................................................21
                    Preferred Capital Stock.................................................21
                    Private Placement Legend................................................21
                    Purchase Amount.........................................................21
                    Purchase Date...........................................................21
                    Purchase Price..........................................................21
                    QIB  ...................................................................21
                    Record Expiration Date..................................................21
                    Redeemable Stock........................................................21
                    Redemption Date.........................................................22
                    Redemption Price........................................................22
                    Registration Rights Agreement...........................................22
                    Registration Statement..................................................22
                    Regular Record Date.....................................................22
                    Regulation S............................................................22
                    Required Consent........................................................22
                    Restricted Payments.....................................................23
                    Restricted Subsidiary...................................................23
                    Rule 144A...............................................................23
                    S&P  ...................................................................23
                    Securities..............................................................23
                    Securities Act..........................................................23
                    Security Register.......................................................23
                    September Indenture.....................................................23
                    September Notes.........................................................23
                    Series D Debenture Indenture............................................24
                    Series D Preferred Stock................................................24
                    Series E Debenture Indenture............................................24
                    Series E Preferred Stock................................................24
                    Shelf Registration Statement............................................24
                    Special Record Date.....................................................24
</TABLE>

<PAGE>   105
<TABLE>

<S>                                                                                         <C>
                    Specialized Mobile Radio................................................24
                    Stated Maturity.........................................................24
                    Subsidiary..............................................................24
                    Total Common Equity.....................................................25
                    Total Market Value of Equity............................................25
                    Trading Day.............................................................25
                    Trustee.................................................................25
                    Trust Indenture Act.....................................................25
                    U.S. Global Securities..................................................25
                    U.S. Government Obligation..............................................25
                    U.S. Physical Securities................................................25
                    Unrestricted Subsidiary.................................................25
                    Vendor Financing Debt...................................................26
                    Vice President..........................................................26
                    Voting Stock............................................................26
                    Wholly Owned Restricted Subsidiary......................................26

SECTION 102.  Compliance Certificates and Opinions..........................................26

SECTION 103.  Form of Documents Delivered to Trustee........................................27

SECTION 104.  Acts of Holders; Record Dates.................................................27

SECTION 105.  Notices, Etc., to Trustee and Company.........................................29

SECTION 106.  Notice to Holders; Waiver.....................................................30

SECTION 107.  Conflict with Trust Indenture Act.............................................30

SECTION 108.  Effect of Headings and Table of Contents......................................31

SECTION 109.  Successors and Assigns........................................................31

SECTION 110.  Separability Clause...........................................................31

SECTION 111.  Benefits of Indenture.........................................................31

SECTION 112.  Governing Law.................................................................31

SECTION 113.  Legal Holidays................................................................31

SECTION 114.  No Recourse Against Others....................................................31
</TABLE>

<PAGE>   106
<TABLE>

<S>                                                                                         <C>

                                           ARTICLE TWO

                                         Security Forms

SECTION 201.  Forms Generally...............................................................32

SECTION 202.  Form of Face of Security......................................................33

SECTION 203.  Form of Reverse of Security...................................................35

SECTION 204.  Form of Trustee's Certificate of Authentication...............................41

SECTION 205.  Restrictive Legends...........................................................41

                                          ARTICLE THREE

                                         The Securities

SECTION 301.  Title and Terms...............................................................43

SECTION 302.  Denominations.................................................................44

SECTION 303.  Execution, Authentication, Delivery and Dating................................44

SECTION 304.  Temporary Securities..........................................................44

SECTION 305.  Registration, Registration of Transfer and Exchange...........................45

SECTION 306.  Book-Entry Provisions for Global Security.....................................46

SECTION 307.  Special Transfer Provisions...................................................47

SECTION 308.  Mutilated, Destroyed, Lost and Stolen Securities..............................50

SECTION 309.  Payment of Interest; Interest Rights Preserved................................51

SECTION 310.  Persons Deemed Owners.........................................................52

SECTION 311.  Cancellation..................................................................52

SECTION 312.  Computation of Interest.......................................................52

SECTION 313.  CUSIP, CINS and ISIN Numbers..................................................53



                                          ARTICLE FOUR

                                    Satisfaction and Discharge

SECTION 401.  Satisfaction and Discharge of Indenture.......................................53

SECTION 402.  Application of Trust Money....................................................54
</TABLE>

<PAGE>   107
<TABLE>

<S>                                                                                         <C>
                                         ARTICLE FIVE

                                           Remedies

SECTION 501.  Events of Default.............................................................54

SECTION 502.  Acceleration of Maturity; Rescission and Annulment............................56

SECTION 503.  Collection of Indebtedness and Suits for Enforcement by
                    Trustee.................................................................58

SECTION 504.  Trustee May File Proofs of Claim..............................................58

SECTION 505.  Trustee May Enforce Claims Without Possession of
                    Securities..............................................................59

SECTION 506.  Application of Money Collected................................................59

SECTION 507.  Limitation on Suits...........................................................59

SECTION 508.  Unconditional Right of Holders to Receive Principal,
                    Premium and Interest....................................................60

SECTION 509.  Restoration of Rights and Remedies............................................60

SECTION 510.  Rights and Remedies Cumulative................................................60

SECTION 511.  Delay or Omission Not Waiver..................................................61

SECTION 512.  Control by Holders............................................................61

SECTION 513.  Waiver of Past Defaults.......................................................61

SECTION 514.  Undertaking for Costs.........................................................62

SECTION 515.  Waiver of Stay or Extension Laws..............................................62

                                            ARTICLE SIX

                                            The Trustee

SECTION 601.  Certain Duties and Responsibilities...........................................62

SECTION 602.  Notice of Defaults............................................................62

SECTION 603.  Certain Rights of Trustee.....................................................63

</TABLE>

<PAGE>   108
<TABLE>

<S>                                                                                         <C>
SECTION 604.  Not Responsible for Recitals or Issuance of Securities........................64

SECTION 605.  May Hold Securities...........................................................64

SECTION 606.  Money Held in Trust...........................................................64

SECTION 607.  Compensation and Reimbursement................................................64

SECTION 608.  Conflicting Interests.........................................................65

SECTION 609.  Corporate Trustee Required; Eligibility.......................................65

SECTION 610.  Resignation and Removal; Appointment of Successor.............................65

SECTION 611.  Acceptance of Appointment by Successor........................................67

SECTION 612.  Merger, Conversion, Consolidation or Succession to
                    Business................................................................67

SECTION 613.  Preferential Collection of Claims Against Company.............................67

SECTION 614.  Appointment of Authenticating Agent...........................................68


                                           ARTICLE SEVEN

                            Holders' Lists and Reports by Trustee and Company

SECTION 701.  Company to Furnish Trustee Names and Addresses of
                    Holders.................................................................69

SECTION 702.  Preservation of Information; Communications to Holders........................70

SECTION 703.  Reports by Trustee............................................................70

SECTION 704.  Reports by Company............................................................70

                                            ARTICLE EIGHT

                           Consolidation, Merger, Conveyance, Transfer or Lease

SECTION 801.  Company May Consolidate, Etc..................................................71

SECTION 802.  Successor Substituted.........................................................72


                                            ARTICLE NINE

                                      Supplemental Indentures

SECTION 901.  Supplemental Indentures Without Consent of Holders............................72

</TABLE>

<PAGE>   109
<TABLE>

<S>                                                                                         <C>
SECTION 902.  Supplemental Indentures with Consent of Holders...............................73

SECTION 903.  Execution of Supplemental Indentures..........................................74

SECTION 904.  Effect of Supplemental Indentures.............................................74

SECTION 905.  Conformity with Trust Indenture Act...........................................74

SECTION 906.  Reference in Securities to Supplemental Indentures............................74

                                           ARTICLE TEN

                                            Covenants

SECTION 1001.  Payment of Principal, Premium and Interest...................................75

SECTION 1002.  Maintenance of Office or Agency..............................................75

SECTION 1003.  Money for Security Payments to be Held in Trust..............................75

SECTION 1004.  Existence....................................................................76

SECTION 1005.  Maintenance of Properties....................................................77

SECTION 1006.  Payment of Taxes and Other Claims............................................77

SECTION 1007.  Maintenance of Insurance.....................................................77

SECTION 1008.  Limitation on Consolidated Debt..............................................78

SECTION 1009.  Limitation on Restricted Payments............................................78

SECTION 1010.  Restricted Subsidiaries......................................................81

SECTION 1011.  Transactions with Affiliates.................................................83

SECTION 1012.  [Intentionally Omitted]......................................................83

SECTION 1013.  Change of Control............................................................83

SECTION 1014.  [Intentionally Omitted]......................................................83

SECTION 1015.  Activities of the Company and Restricted Subsidiaries........................83

</TABLE>

<PAGE>   110
<TABLE>

<S>                                                                                         <C>
SECTION 1016.  Provision of Financial Information...........................................84

SECTION 1017.  Statement by Officers as to Default; Compliance
                    Certificates............................................................84

SECTION 1018.  Waiver of Certain Covenants..................................................84

                                          ARTICLE ELEVEN

                                    Redemption of Securities

SECTION 1101.  Right of Redemption..........................................................85

SECTION 1102.  Applicability of Article.....................................................86

SECTION 1103.  Election to Redeem; Notice to Trustee........................................86

SECTION 1104.  Selection by Trustee of Securities to Be Redeemed............................86

SECTION 1105.  Notice of Redemption.........................................................86

SECTION 1106.  Deposit of Redemption Price..................................................87

SECTION 1107.  Securities Payable on Redemption Date........................................87

SECTION 1108.  Securities Redeemed in Part..................................................88

                                          ARTICLE TWELVE

                               Defeasance and Covenant Defeasance

SECTION 1201.  Company's Option to Effect Defeasance or Covenant
                    Defeasance..............................................................88

SECTION 1202.  Defeasance and Discharge.....................................................88

SECTION 1203.  Covenant Defeasance..........................................................89

SECTION 1204.  Conditions to Defeasance or Covenant Defeasance..............................89

SECTION 1205.  Deposited Money and U.S. Government Obligations to Be
                    Held in Trust; Miscellaneous Provisions.................................91

SECTION 1206.  Reinstatement................................................................92

</TABLE>

<PAGE>   111

                                    EXHIBITS

 EXHIBIT A      Form of Certificate to Be Delivered in Connection with Transfers
                Pursuant to Regulation S

 EXHIBIT B      Form of Certificate to Be Delivered in Connection with Transfers
                to Non-QIB Institutional Accredited Investors

 EXHIBIT C      Form of Certificate to Be Delivered in Connection with
                Transfers Pursuant to Regulation S