Document:

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                                                                     EXHIBIT 4.2

                              AETHER SYSTEMS, INC.

                                       and

                           FIRST UNION NATIONAL BANK,
                                   as Trustee

                                    INDENTURE

                           Dated as of March ___, 2000

                 _____% Convertible Subordinated Notes due 2005

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                                TABLE OF CONTENTS

                                                                            PAGE

SIGNATURES
ACKNOWLEDGMENTS
EXHIBIT A - FORMS OF CERTIFICATION
EXHIBIT A-2 - FORM OF RESTRICTIVE LEGEND

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                               TABLE OF CONTENTS

<TABLE>
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ARTICLE 1 DEFINITIONS AND OTHER PROVISIONS OF
        GENERAL APPLICATION..............................................................1
        Section 1.01.  Definitions.......................................................1
        Section 1.02.  Compliance Certificates and Opinions..............................8
        Section 1.03.  Form of Documents Delivered to Trustee............................8
        Section 1.04.  Acts of Holders...................................................9
        Section 1.05.  Notices, Etc., to Trustee and Company.............................10
        Section 1.06.  Notice to Holders; Waiver.........................................11
        Section 1.07.  Effect of Headings and Table of Contents..........................11
        Section 1.08.  Successors and Assigns............................................11
        Section 1.09.  Separability Clause...............................................11
        Section 1.10.  Benefits of Indenture.............................................12
        Section 1.11.  Governing Law.....................................................12
        Section 1.12.  Legal Holidays....................................................12
        Section 1.13.  Personal Immunity from Liability for Incorporators,
                Stockholders, Etc........................................................12
        Section 1.14.  Conflict with Trust Indenture Act.................................12
ARTICLE 2 SECURITIES FORMS...............................................................13
        Section 2.01.  Forms of Securities...............................................13
        Section 2.02.  Form of Trustee's Certificate of Authentification.................13
        Section 2.03.  Securities Issuable in Global Form................................13
ARTICLE 3 THE SECURITIES.................................................................14
        Section 3.01.  Title and Term....................................................14
        Section 3.02.  Denominations.....................................................14
        Section 3.03.  Execution, Authentication, Delivery and Dating....................14
        Section 3.04.  Registration, Registration of Transfer and Exchange...............15
        Section 3.05.  Mutilated, Destroyed, Lost and Stolen Securities..................17
        Section 3.06.  Payment of Interest, Interest Rights Preserved....................17
        Section 3.07.  Persons Deemed Owners.............................................19
        Section 3.08.  Cancellation......................................................19
        Section 3.09.  Computation of Interest...........................................19
ARTICLE 4 SATISFACTION AND DISCHARGE.....................................................20
        Section 4.01.  Satisfaction and Discharge of Indenture...........................20
        Section 4.02.  Application of Trust Funds........................................20
ARTICLE 5 REMEDIES.......................................................................21
        Section 5.01.  Events of Default.................................................21
        Section 5.02.  Acceleration of Maturity; Rescission and Annulment................22
        Section 5.03.  Collection of Indebtedness and Suits for Enforcement by
                    Trustee..............................................................23
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<TABLE>
<S>                                                                                     <C>
        Section 5.04.  Trustee May File Proofs of Claim..................................24
        Section 5.05.  Trustee May Enforce Claims Without Possession of Securities.......25
        Section 5.06.  Application of Money Collected....................................25
        Section 5.07.  Limitation of Suits...............................................25
        Section 5.08.  Unconditional Right of Holders to Receive Principal,
                Premium, If Any, and Interest............................................26
        Section 5.09.  Restoration of Rights and Remedies................................26
        Section 5.10.  Rights and Remedies Cumulative....................................26
        Section 5.11.  Delay or Omission Not Waiver......................................27
        Section 5.12.  Control by Holders of Securities..................................27
        Section 5.13.  Waiver of Past Defaults...........................................27
        Section 5.14.  Waiver of Usury, Stay or Extension Laws...........................27
        Section 5.15.  Undertaking for Costs.............................................28
ARTICLE 6 THE TRUSTEE....................................................................28
        Section 6.01.  General...........................................................28
        Section 6.02.  Certain Rights of Trustee.........................................28
        Section 6.03.  Individual Rights of Trustee......................................30
        Section 6.04.  Trustee's Disclaimer..............................................30
        Section 6.05.  Notice of Default.................................................30
        Section 6.06.  Conflicting Interests of Trustee..................................30
        Section 6.07.  Compensation and Indemnity........................................30
        Section 6.08.  Replacement of Trustee............................................31
        Section 6.09.  Successor Trustee by Merger, Etc..................................32
        Section 6.10.  Eligibility.......................................................32
        Section 6.11.  Money Held in Trust...............................................32
        Section 6.12.  Withholding Taxes.................................................33
        Section 6.13.  Preferential Collection of Claims.................................33
        Section 6.14.  Trustee's Application for Instructions from the Company...........33
ARTICLE 7 HOLDERS' LISTS AND REPORTS BY TRUSTEE AND
        COMPANY..........................................................................33
        Section 7.01.  Disclosure of Names and Addresses of Holders......................33
        Section 7.02.  Reports by Trustee................................................33
        Section 7.03.  Reports by Company................................................34
        Section 7.04.  Company to Furnish Trustee Names and Addresses of Holders.........34
ARTICLE 8 CONSOLIDATION, MERGER, SALE, LEASE OR
        CONVEYANCE.......................................................................35
        Section 8.01.  Consolidations and Mergers of Company and Sales, Leases
                and Conveyances Permitted Subject to Certain Conditions..................35
        Section 8.02.  Rights and Duties of Successor Corporation........................35
        Section 8.03.  Officers' Certificate and Opinion of Counsel......................36
ARTICLE 9 SUPPLEMENTAL INDENTURES........................................................36
        Section 9.01.  Supplemental Indentures Without Consent of Holders................36
        Section 9.02.  Supplemental Indentures with Consent of Holders...................37
        Section 9.03.  Execution of Supplemental Indentures..............................37
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<TABLE>
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        Section 9.04.  Effect of supplemental Indentures.................................38
        Section 9.05.  Conformity with Trust Indenture Act...............................38
        Section 9.06.  Reference in Securities to Supplemental Indentures................38
ARTICLE 10 COVENANTS.....................................................................38
        Section 10.01.  Payment of Principal, Premium, If Any, and Interest..............38
        Section 10.02.  Maintenance of Office or Agency..................................38
        Section 10.03.  Money for Securities Payments to Be Held in Trust................39
        Section 10.04.  Existence........................................................40
        Section 10.05.  Payment of Taxes and Other Claims................................40
        Section 10.06.  Statement as to Compliance.......................................40
        Section 10.07.  Waiver of Certain Covenants......................................41
ARTICLE 11 REDEMPTION OF SECURITIES......................................................41
        Section 11.01.  Provisional and Optional Redemption by the Company...............41
        Section 11.02.  Election to Redeem; Notice to Trustee............................42
        Section 11.03.  Selection by Trustee of Securities to Be Redeemed................42
        Section 11.04.  Notice of Redemption.............................................42
        Section 11.05.  Deposit of Redemption Price......................................44
        Section 11.06.  Securities Payable on Redemption Date............................44
        Section 11.07.  Securities Redeemed in Part......................................44
ARTICLE 12 REPURCHASE AT OPTION OF HOLDERS UPON
        CHANGE IN CONTROL................................................................45
        Section 12.01.  Right to Require Repurchase......................................45
        Section 12.02.  Conditions to the Company's Election to Pay the Repurchase
                Price in Common Stock....................................................45
        Section 12.03.  Notices; Method of Exercising Repurchase Right, Etc..............46
        Section 12.04.  Certain Definitions..............................................49
        Section 12.05.  Change in Control................................................49
        Section 12.06.  References to Repurchase Price...................................50
ARTICLE 13 CONVERSION....................................................................50
        Section 13.01.  Conversion Privilege and Conversion Price........................50
        Section 13.02.  Exercise of Conversion Privilege.................................51
        Section 13.03.  Fraction of Shares...............................................52
        Section 13.04.  Adjustment of Conversion Price...................................53
        Section 13.05.  Notice of Adjustments of Conversion Price........................59
        Section 13.06.  Notice of Certain Corporate Action...............................59
        Section 13.07.  Company's Obligation Regarding Common Stock......................60
        Section 13.08.  Taxes on Conversions.............................................60
        Section 13.09.  Covenant as to Common Stock......................................60
        Section 13.10.  Cancellation of Converted Securities.............................61
        Section 13.11.  Provisions in Case of Reclassification, Consolidation, Merger
                or Sale of Assets........................................................61
        Section 13.12.  Company's Obligation.............................................61
ARTICLE 14 SUBORDINATION.................................................................61
        Section 14.01  Securities Subordinate to Senior Indebtedness.....................61
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<TABLE>
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        Section 14.02.  Payment over of Proceeds upon Dissolution, Etc...................62
        Section 14.03.  No Payment When Senior Indebtedness in Default...................63
        Section 14.04.  Payment Permitted If No Default..................................63
        Section 14.05.  Subrogation to Rights of Holders of Senior Indebtedness..........64
        Section 14.06.  Provisions Solely to Define Relative Rights......................64
        Section 14.07.  Trustee to Effectuate Subordination..............................65
        Section 14.08.  No Waiver of Subordination Provisions............................65
        Section 14.09.  Notice to Trustee................................................65
        Section 14.10.  Reliance on Judicial Order or Certificate of Liquidating
                Agent....................................................................66
        Section 14.11.  Trustee No Fiduciary for Holders of Senior Indebtedness..........66
        Section 14.12.  Rights of Trustee as Holder of Senior Indebtedness;
                Preservation of Trustee's Rights.........................................66
        Section 14.13.  Article Applicable to Paying Agents..............................67
        Section 14.14.  Certain Conversions Deemed Payment...............................67
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        INDENTURE, dated as of March ___, 2000, between AETHER SYSTEMS, INC., a
Delaware corporation (the "COMPANY"), having its principal office at 11460
Cronridge Drive, Owings Mills, Maryland 21117 and FIRST UNION NATIONAL BANK, a
national banking association organized under the laws of the United States of
America, as Trustee hereunder (the "TRUSTEE"), having an office at 800 East Main
Street, Richmond, Virginia 23219.

                             RECITALS OF THE COMPANY

        The Company has duly authorized the issue of its _____% Convertible
Subordinated Notes due 2005 (the "SECURITIES"), and to provide for such
issuance, the Company has duly authorized the execution and delivery of this
Indenture.

        This Indenture is subject to the provisions of the Trust Indenture Act
that are deemed to be incorporated into this Indenture and shall, to the extent
applicable, be governed by such provisions.

        All things necessary to make this Indenture a valid agreement of the
Company, in accordance with 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 the holders of the Securities, as
follows:

                                    ARTICLE 1
             DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

        Section 1.01. 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 TIA, either
directly or by reference therein, have the meanings assigned to them therein,
and the terms "cash transaction" and "self-liquidating paper," as used in TIA
Section 311, shall have the meanings assigned to them in the rules of the
Commission adopted under the TIA;

        (3) all accounting terms not otherwise defined herein have the meanings
assigned to them in accordance with GAAP;

        (4) the word "including" means "including without limitation," and

        (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.

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        "ACT," when used with respect to any Holder, has the meaning specified
in Section 1.04.

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

        "AUTHORIZED NEWSPAPER" means a newspaper, printed in the English
language or in an official language of the country of publication, customarily
published on each Business Day, whether or not published on Saturdays, Sundays
or holidays, and of general circulation in each place in connection with which
the term is used or in the financial community of each such place. Whenever
successive publications are required to be made in Authorized Newspapers, the
successive publications may be made in the same or in different Authorized
Newspapers in the same city meeting the foregoing requirements and in each case
on any Business Day.

        "BANKRUPTCY LAW" has the meaning specified in Section 5.01.

        "BOARD OF DIRECTORS" means the board of directors of the Company, the
executive committee of that board or any committee of that board duly authorized
to act hereunder.

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

        "BUSINESS DAY," when used with respect to any Place of Payment or any
other particular location referred to in this Indenture or in the Securities,
means, any day, other than a Saturday or Sunday, that is neither a legal holiday
nor a day on which banking institutions in that Place of Payment or particular
location are authorized or required by law, regulation or executive order to
close.

        "CLOSING PRICE" has the meaning specified in Section 13.03.

        "COMMISSION" means the Securities and Exchange Commission, as from time
to time constituted, created under the Securities Exchange Act of 1934, or, if
at any time after 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 on such date.

        "COMMON STOCK" means the common stock of the Company, $0.01 par value,
as it exists on the date of this Indenture and any shares of any class or
classes of capital stock of the Company resulting from any reclassification or
reclassifications thereof.

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

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        "COMPANY REQUEST" and "COMPANY ORDER" mean, respectively, a written
request or order signed in the name of the Company by the Chief Executive
Officer, Chief Financial Officer, the President or a Vice President of the
Company and delivered to the Trustee.

        "CONVERSION AGENT" means any Person authorized by the Company pursuant
to Section 10.02 to convert Securities in accordance with Article 13.

        "CONVERSION RATE" has the meaning specified in Section 13.01.

        "CORPORATE TRUST OFFICE" means the office of the Trustee at which, at
any particular time, its corporate trust business as it relates to this
Indenture shall be principally administered, which office at the date hereof is
located at__________.

        "CORPORATION" means a corporation, association, partnership, companies
(including limited liability companies) joint-stock company or business trust.

        "CUSTODIAN" has the meaning specified in Section 5.01.

        "DEFAULTED INTEREST" has the meaning specified in Section 3.06.

        "DOLLAR" or "$" means a dollar or other equivalent unit in such coin or
currency of the United States of America as at the time shall be legal tender
for the payment of public and private debts.

        "DTC" means The Depository Trust Company.

        "EVENT OF DEFAULT" has the meaning specified in Article 5.

        "GAAP" means generally accepted accounting principles, as in effect from
time to time, as used in the United States, applied on a consistent basis.

        "GOVERNMENT OBLIGATIONS" means securities which are (i) direct
obligations of the United States of America, for the payment of which its full
faith and credit is pledged or (ii) obligations of a Person controlled or
supervised by and acting as an agency or instrumentality of the United States of
America, the payment of which is unconditionally guaranteed as a full faith and
credit obligation by the United States of America, which is not callable or
redeemable at the option of the issuer thereof, and shall also include a
depository receipt issued by a bank or trust company as custodian with respect
to any such Government Obligation or a specific payment of interest on or
principal of any such Government Obligation held by such custodian for the
account of the holder of a depository receipt, provided that (except as required
by law) such custodian is not authorized to make any deduction from the amount
payable to the holder of such depository receipt from any amount received by the
custodian in respect of the Government Obligation or the specific payment of
interest on or principal of the Government Obligation evidenced by such
depository receipt.

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

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        "INDEBTEDNESS" means, with respect to any Person, and without
duplication, (a) all indebtedness, obligations and other liabilities (contingent
or otherwise) of such Person for borrowed money (including obligations of such
Person in respect of overdrafts, foreign exchange contracts, currency exchange
or similar agreements, interest rate protection, hedging or similar agreements,
and any loans or advances from banks, whether or not evidenced by notes or
similar instruments) or evidenced by bonds, debentures, notes or similar
instruments (whether or not the recourse of the lender is to the whole of the
assets of such Person or to only a portion thereof) other than any account
payable or other accrued current liability or obligation, in each case incurred
in the ordinary course of business in connection with the obtaining of materials
or services; (b) all reimbursement obligations and other liabilities (contingent
or otherwise) of such Person with respect to letters of credit, bank guarantees,
bankers' acceptances, security purchase facilities or similar credit
transactions; (c) all obligations and liabilities (contingent or otherwise) in
respect of deferred and unpaid balances on any purchase price of any property;
(d) all obligations and liabilities (contingent or otherwise) in respect of
leases of such Person required, in conformity with generally accepted accounting
principles, to be accounted for as capitalized lease obligations on the balance
sheet of such Person and all obligations and other liabilities (contingent or
otherwise) under any lease or related document, including, without limitation,
the balance deferred and unpaid on any purchase price of any property and a
purchase agreement, in connection with the lease of real property which provides
that such Person is contractually obligated to purchase or cause a third party
to purchase the leased property and thereby guarantee a minimum residual value
of the leased property to the lessor and the obligations of such Person under
such lease or related document to purchase or to cause a third party to purchase
such leased property; (e) all obligations of such Person (contingent or
otherwise) with respect to an interest rate or other swap, cap or collar
agreement or other similar instrument or agreement or foreign currency hedge,
exchange, purchase or similar instrument or agreement; (f) all direct or
indirect guarantees or similar agreements by such Person in respect of, and
obligations or liabilities (contingent or otherwise) of such Person to purchase
or otherwise acquire or otherwise assure a creditor against loss in respect of
indebtedness, obligations or liabilities of another Person of the kind described
in clauses (a) through (f); (g) any indebtedness or other obligations described
in clauses (a) through (f) secured by any mortgage, pledge, lien or other
encumbrance existing on property which is owned or held by such Person,
regardless of whether the indebtedness or other obligation secured thereby shall
have been assumed by such Person; and (h) any and all deferrals, renewals,
extensions, refinancing, replacements, restatements and refundings of, or
amendments, modifications or supplements to, or any indebtedness, or obligation
issued in exchange for, any indebtedness, obligation or liability of the kind
described in clauses (a) through (g).

        "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.

        "INTEREST PAYMENT DATE," means the Stated Maturity of an installment of
interest on such Security.

        "MAKE-WHOLE PAYMENT" has the meaning specified in Section 11.01.

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        "MATURITY," means the date on which the principal of the Securities
becomes due and payable as therein or herein provided, whether at the Stated
Maturity, conversion or by declaration of acceleration, notice of redemption,
notice of option to elect repayment or otherwise.

        "MATERIAL ADVERSE EFFECT" has the meaning specified in Section 10.04.

        "OFFICERS' CERTIFICATE" means a certificate signed by the Chairman of
the Board of Directors, 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.

        "OPINION OF COUNSEL" means a written opinion of counsel, who may be
counsel for the Company or who may be an employee of or other counsel for the
Company and who shall be reasonably satisfactory 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, or portions thereof, for whose payment or redemption
or repayment at the option of the Holder, 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 3.05 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 converted into Common Stock pursuant to or in
accordance with this Indenture;

provided, however, that in determining whether the Holders of the requisite
principal amount of the Outstanding Securities have given any request, demand,
authorization, direction, notice, consent or waiver hereunder or are present at
a meeting of Holders for quorum purposes, and for the purpose of making the
calculations required by TIA Section 313, 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 making such
calculation or in relying upon any such request, demand, authorization,
direction, notice, consent or waiver, only Securities which the Trustee knows to
be so owned shall be so disregarded. Securities so owned which have been pledged
in good faith may be regarded as Outstanding if the pledgee establishes to the

                                       -5-

<PAGE>   12

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.

        "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.

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

        "PLACE OF PAYMENT," means the place or places where the principal of
(and premium, if any), interest on and the Redemption Prices and the Repurchase
Price with respect to the Securities are payable as specified as contemplated by
Section 10.2.

        "PREDECESSOR SECURITY" means every previous Security evidencing all or a
portion of the same debt as that evidenced by such Security; and, for the
purposes of this definition, any Security authenticated and delivered under
Section 3.05 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.

        "REDEMPTION DATE," when used with respect to any Security to be
redeemed, in whole or in part, means the date fixed for such redemption by or
pursuant to this Indenture as set forth in such Security.

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

        "REGULAR RECORD DATE" for the interest payable on any Interest Payment
Date on the Securities means the date specified for that purpose as contemplated
by Section 3.06, whether or not a Business Day.

        "REPURCHASE DATE" means, when used with respect to any Security to be
repaid at the option of the Holder, the date fixed for such repayment by or
pursuant to this Indenture.

        "REPURCHASE PRICE" means, when used with respect to any Security to be
repaid at the option of the Holder, the price at which it is to be repaid by or
pursuant to this Indenture.

        "RESPONSIBLE OFFICER," when used with respect to the Trustee, means the
chairman or vice-chairman of the Board of Directors, the chairman or
vice-chairman of the executive committee of the Board of Directors, the
president, any vice president (whether or not designated by a number or a word
or words added before or after the title "vice president,") the secretary, any
assistant secretary, the treasurer, any assistant treasurer, any corporate trust
officer, the controller or any other officer of the Trustee customarily
performing functions similar to those performed by any of the above designated
officers and also means, with respect to a particular corporate trust matter,
any other officer to whom such matter is referred because of such officer's
knowledge and familiarity with the particular subject.

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<PAGE>   13

        "SECURITY" has the meaning stated in the first recital of this Indenture
and, more particularly, means any Security or Securities authenticated and
delivered under this Indenture.

        "SECURITY REGISTER" and "SECURITY REGISTRAR" have the respective
meanings specified in Section 3.04.

        "SENIOR INDEBTEDNESS" means the principal of, premium, if any, interest
(including all interest accruing subsequent to the commencement of any
bankruptcy or similar proceeding, whether or not a claim for post-petition
interest is allowable as a claim in any such proceeding) and all other amounts
owed in respect of all Indebtedness of the Company, whether outstanding on the
date of this Indenture or thereafter created, incurred, assumed, guaranteed or
in effect guaranteed by the Company (including all deferrals, renewals,
extensions, refinancings, replacements, restatements or refundings of, or
amendments, modifications or supplements to, the foregoing); except for (i) any
such Indebtedness the terms of which expressly provide that such Indebtedness
shall not be senior in right of payment to the Securities, (ii) any such
Indebtedness that is by its terms subordinated to or pari passu with the
Securities, and (iii) any Indebtedness between or among the Company or any of
its Subsidiaries or its Affiliates, including all other debt securities and
guarantees in respect of those debt securities issued to any trust, or trustees
of any trust, partnership or other entity affiliated with the Company that is,
directly or indirectly, a financing vehicle used by the Company in connection
with the issuance by that financing vehicle of preferred securities or other
securities that rank pari passu with, or junior to, the Securities.

        "SIGNIFICANT SUBSIDIARY" means any Subsidiary which is a "significant
subsidiary" (as defined in Article 1, Rule 1-02 of Regulation S-X, promulgated
under the Securities Act of 1933) of the Company.

        "SPECIAL RECORD DATE" for the payment of any Defaulted Interest on the
Securities means a date fixed by the Trustee pursuant to Section 3.06.

        "STATED MATURITY," means the date specified in the Securities as the
fixed date on which the principal of, or interest on, such Securities is due and
payable.

        "SUBSIDIARY" means a corporation a majority of the outstanding voting
stock of which is owned, directly or indirectly, by the Company or by one or
more other Subsidiaries of the Company, or by the Company and one or more other
Subsidiaries. For the purposes of this definition, "VOTING STOCK " means stock
that ordinarily has voting power for the election of directors, whether at all
times or only so long as no senior class of stock has such voting power by
reason of any contingency.

        "TRADING DAY" has the meaning specified in Section 13.03.

        "TRUST INDENTURE ACT" or "TIA" means the Trust Indenture Act of 1939, as
amended, as in force at the date hereof; provided, however, that in the event
the Trust Indenture Act of 1939 or such rules and regulations are amended after
such date, "TRUST INDENTURE ACT" means, to the extent required by any such
amendment, the Trust Indenture Act of 1939 and such rules and regulations as so
amended.

                                       -7-

<PAGE>   14

        "TRUSTEE" means the Person named as the "Trustee" in the first paragraph
of this Indenture until a successor Trustee shall have become such pursuant to
the applicable provisions of this Indenture, and thereafter "Trustee" shall mean
or include each Person who is then a Trustee hereunder.

        "UNITED STATES" means the United States of America (including the states
and the District of Columbia), its territories, its possessions and other areas
subject to its jurisdiction.

        Section 1.02. Compliance Certificates and Option. 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 an Officers'
Certificate stating that all conditions precedent, if any, provided for in this
Indenture relating to the proposed action have been complied with and an Opinion
of Counsel stating that in the opinion of such counsel all such conditions
precedent, if any, have been complied with, except that in the case of any such
application or request as to which the furnishing of such documents is
specifically required by any provision of this Indenture relating to such
particular application or request, no additional certificate or opinion need be
refurnished.

        Every certificate or opinion with respect to compliance with a condition
or covenant provided for in this Indenture shall include:

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

        (b) a brief statement as to the nature and scope of the examination or
investigation upon which the statements or opinions contained in such
certificate or opinion are based;

        (c) a statement that, in the opinion of 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 condition or covenant has been
complied with; and

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

        Section 1.03. 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 as 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 an Opinion of Counsel, or a
certificate or representations by counsel, unless such officer knows, or in the
exercise of reasonable care should know, that the opinion, certificate or
representations with respect to the matters upon which his certificate or
opinion is based are erroneous. Any such Opinion of Counsel or certificate or
representations may be based, insofar as it relates to factual matters, upon a
certificate or opinion of, or representations

                                       -8-

<PAGE>   15

by, an officer or officers of the Company stating that the information as to
such factual matters is in the possession of the Company, unless such counsel
knows that the certificate or opinion or representations as 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 1.04. Acts of Holders. (a) Any request, demand, authorization,
direction, notice, consent, waiver or other action provided by this Indenture to
be given or taken by Holders of the Outstanding Securities, may be embodied in
and evidenced by one or more instruments of substantially similar tenor signed
by such Holders in person or by agents duly appointed in writing. Except as
herein otherwise expressly provided, such action shall become effective when
such instrument or instruments or record or both are delivered to the Trustee
and, where it is hereby expressly required, to the Company. Such instrument or
instruments and any such record (and the action embodied therein and evidenced
thereby) are herein sometimes referred to as the "ACT" of the Holders signing
such instrument or instruments or so voting at any such meeting. Proof of
execution of any such instrument or of a writing appointing any such agent, or
of the holding by any Person of a Security, shall be sufficient for any purpose
of this Indenture and conclusive in favor of the Trustee and the Company and any
agent of the Trustee or the Company, if made in the manner provided in this
Section 1.04.

        (b) 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 reasonable manner which the Trustee deems sufficient.

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

        (d) (i) If the Company shall solicit from the Holders of any request,
demand, authorization, direction, notice, consent, waiver or other Act, the
Company may, at its option, in or pursuant to a Board Resolution, fix in advance
a record date for the determination of Holders entitled to give such request,
demand, authorization, direction, notice, consent, waiver or other Act, but the
Company shall have no obligation to do so; provided that the Company shall not
be entitled to 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 clause 1.04(d)(iii) below. Notwithstanding
TIA Section 316(c), such record date shall be the record date specified in or
pursuant to such Board Resolution, which shall be a date not earlier than the
date 30 days prior to the first solicitation of Holders generally in connection
therewith and not later than the date such solicitation is completed. If such a
record date is fixed, such request, demand, authorization, direction, notice,
consent, waiver or other Act may be given before or after such record date, but
only the Holders of record at the close of business on such record date

                                       -9-

<PAGE>   16

shall be deemed to be Holders for the purposes of determining whether Holders of
the requisite proportion of Outstanding Securities have authorized or agreed or
consented to such request, demand, authorization, direction, notice, consent,
waiver or other Act, and for that purpose the Outstanding Securities shall be
computed as of such record date; provided that no such authorization, agreement
or consent by the Holders on such record date shall be deemed effective unless
it shall become effective pursuant to the provisions of this Indenture not later
than eleven months after the record date.

        (ii)  Subject to clause 1.04(d)(iii) below, in the absence of any such
record date fixed by the Company, regardless as to whether any solicitation of
the Holders is occurring on behalf of the Company or any Holder, the Trustee
may, at its option, fix in advance a record date for the determination of such
Holders entitled to give such request, demand, authorization, direction, notice,
consent, waiver or other Act, but the Trustee shall have no obligation to do so.
Any such record date shall be a date not more than 30 days prior to the first
solicitation of Holders generally in connection therewith and no later than the
date of such solicitation.

        (iii) 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 (A) any notice of default, (B) any declaration of acceleration
referred to in Section 5.02, (C) any request to institute proceedings referred
to in Section 5.07(b), or (D) any direction referred to in Section 5.12. 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 any applicable expiration date
by Holders of the requisite principal amount of Outstanding Securities on such
record date. 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
cancelled 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 proposed action
by Holders and the applicable expiration date to be given to the Company in
writing and to each Holder of Securities in the manner set forth in Section
1.06.

              (e) 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, any
Security Registrar, any Paying Agent or the Company in reliance thereon, whether
or not notation of such action is made upon such Security.

        Section 1.05. 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:

                                      -10-

<PAGE>   17

        (a) the Trustee by any Holder or by the Company shall be sufficient for
        every purpose hereunder if made, given, furnished or filed in writing to
        or with the Trustee at its __________ Office, Attention: __________;
        provided that notices to the Trustee shall only be deemed given when
        actually received by the Trustee,

        (b) 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 Indenture or at any other address previously
        furnished in writing to the Trustee by the Company.

        Section 1.06. Notice to Holders; Waiver. Where this Indenture provides
for notice of any event to Holders by the Company or the Trustee, such notice
shall be sufficiently given (unless otherwise herein expressly provided) if in
writing and mailed, first-class postage prepaid, to each such Holder affected by
such event, at his address as it appears in the Security Register, not later
than the latest date, and not earlier than the earliest date, 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 given as provided herein. Any notice mailed to a Holder
in the manner herein prescribed shall be conclusively deemed to have been
received by such Holder, whether or not such Holder actually receives such
notice.

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

        Any request, demand, authorization, direction, notice, consent or waiver
required or permitted under this Indenture shall be in the English language,
except that any published notice may be in an official language of the country
of publication.

        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.

        Section 1.07. 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 1.08. 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 1.09. Separability Clause. In case any provision in this
Indenture or in any Security 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.

                                      -11-

<PAGE>   18

        Section 1.10. Benefits of Indenture. Nothing in this Indenture or in the
Securities, express or implied, shall give to any Person, other than the parties
hereto, any Security Registrar, any Paying Agent and their successors hereunder
and the Holders any benefit or any legal or equitable right, remedy or claim
under this Indenture.

        Section 1.11. Governing Law. This Indenture and the Securities shall be
governed by and construed in accordance with the law of the State of New York
without regard to conflicts of laws principles. This Indenture is subject to the
provisions of the TIA that are required to be part of this Indenture and shall,
to the extent applicable, be governed by such provisions.

        Section 1.12. Legal Holidays. In any case where any Interest Payment
Date, Redemption Date, Repurchase Date, Stated Maturity or Maturity of any
Security or the last date on which a Holder has the right to convert his
Securities shall not be a Business Day at any Place of Payment, then
(notwithstanding any other provision of this Indenture or any Security), payment
of Redemption Price, Repurchase Price, interest or principal (and premium, if
any), or conversion of the Securities, need not be made at such Place of Payment
on such date, but may be made on the next succeeding Business Day at such Place
of Payment with the same force and effect as if made on the Interest Payment
Date, Redemption Date, Repurchase Date or at the Stated Maturity or Maturity or
on such last day for conversion; provided that no interest shall accrue on the
amount so payable for the period from and after such Interest Payment Date,
Redemption Date, Repurchase Date, Stated Maturity or Maturity or on such last
day for conversion, as the case may be.

        Section 1.13. Personal Immunity form Liability for Incorporators,
Stockholders, Etc. No recourse shall be had for the payment of the principal of
or premium, if any, or interest, if any, on any Security, or for any claim based
thereon, or otherwise in respect of any Security, or based on or in respect of
this Indenture or any indenture supplemental hereto, against any incorporator,
or against any past, present or future stockholder, director or officer, as
such, of the Company or of any successor corporation, whether by virtue of any
constitution, statute or rule of law, or by the enforcement of any assessment or
penalty or otherwise, all such liability being expressly waived and released as
a condition of, and as consideration for, the execution of this Indenture and
the issue of Securities.

        Section 1.14. Conflict with Trust Indenture Act. If any provision hereof
limits, qualifies or conflicts with a provision of the TIA which is required
under such Act to be a part of and govern this Indenture, the latter provision
shall control. If any provision of this Indenture modifies or excludes any
provision of the TIA which 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. To the extent a Security conflicts with a provision in the
Indenture, the Indenture governs.

                                      -12-

<PAGE>   19

                                    ARTICLE 2
                                SECURITIES FORMS

        Section 2.01. Forms of Securities. The Securities shall be in
substantially the form of Exhibit A hereto, and shall have notations, legends or
endorsements required by law, stock exchange rules or usage.

        Section 2.02. Form of Trustee's Certificate of Authentification

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

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

DATED:

                                   ---------------------------------------
                                   as Trustee

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

        Section 2.03. Securities Issuable in Global Form. Except as otherwise
provided in this Section 2.03 or Section 3.04, the Securities shall be issuable
in global form, and any such Security shall represent such of the Outstanding
Securities as shall be specified therein and may provide that it shall represent
the aggregate amount of Outstanding Securities from time to time endorsed
thereon and that the aggregate amount of Outstanding Securities represented
thereby may from time to time be increased or decreased to reflect exchanges.
Any endorsement of a Security in global form to reflect the amount, or any
increase or decrease in the amount, of Outstanding Securities represented
thereby shall be made by the Trustee in such manner and upon instructions given
by such Person or Persons as shall be specified therein or in the Company Order
to be delivered to the Trustee pursuant to Section 3.03. Subject to the
provisions of Section 3.03, the Trustee shall deliver and redeliver any Security
in global form in the manner and upon instructions given by the Person or
Persons specified therein or in the applicable Company Order. If a Company Order
pursuant to Section 3.03 has been, or simultaneously is, delivered, any
instructions by the Company with respect to endorsement or delivery or
redelivery of a Security in global form shall be in writing but need not comply
with Section 1.02 and need not be accompanied by an Opinion of Counsel.

        The provisions of the last sentence of Section 3.03 shall apply to any
Security represented by a Security in global form if such Security was never
issued and sold by the Company and the Company delivers to the Trustee the
Security in global form together with written instructions (which need not
comply with Section 1.02 and need not be accompanied by an Opinion of Counsel)
with regard to the reduction in the principal amount of Securities represented
thereby, together with the written statement contemplated by the last sentence
of Section 3.03.

                                      -13-

<PAGE>   20

        Notwithstanding the provisions of Section 3.07, payment of principal of
and any premium and interest on any Security in global form shall be made to the
Person or Persons specified therein.

        Notwithstanding the provisions of Section 3.07 and except as provided in
the preceding paragraph, the Company, the Trustee and any agent of the Company
and the Trustee shall treat the Holder of such principal amount of Outstanding
Securities represented by a global Security as the Holder of such global
Security in registered form.

        At the instruction of the Company, any Security may be issued in
definitive form, subject to Section 2.01 hereof.

                                    ARTICLE 3
                                 THE SECURITIES

        Section 3.01. Title and Term. The Securities shall be and are hereby
authorized to be designated as "_____% Convertible Subordinated Notes due 2005",
limited in aggregate principal amount to $__________. The Securities shall
mature and the principal thereof shall be due and payable, together will all
accrued and unpaid interest thereon, on __________, 2005. The Securities shall
be convertible into shares of Common Stock, $0.01 par value, of the Company, as
such shares shall be constituted at the time of conversion, in accordance with
Article 13 hereof.

        Section 3.02. Denominations. The Securities shall be issuable in
denominations of $1,000 and any integral multiple thereof.

        Section 3.03. Execution, Authentication, Delivery and Dating. The
Securities shall be executed on behalf of the Company by the Chief Executive
Officer, Chief Financial Officer, the President or a Vice President of the
Company and attested by its Secretary or one of its Assistant Secretaries. The
signature of any of these individuals on the Securities may be manual or
facsimile signatures of the present or any future such authorized officer and
may be imprinted or otherwise reproduced on the Securities.

        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 the Company Order shall authenticate and deliver such Securities.

        Each Security shall be dated the date of its authentication.

        No Security shall be entitled to any benefit under this Indenture or be
valid or obligatory for any purpose unless there appears on such Security a
certificate of authentication substantially

                                      -14-

<PAGE>   21

in the form provided for herein duly executed by the Trustee by manual signature
of an authorized signatory, and such certificate upon any Security shall be
conclusive evidence, and the only evidence, that such Security has been duly
authenticated and delivered hereunder and is entitled to the benefits of this
Indenture. Notwithstanding the foregoing, if any Security shall have been
authenticated and delivered hereunder but never issued and sold by the Company,
and the Company shall deliver such Security to the Trustee for cancellation as
provided in Section 3.08 together with a written statement (which need not
comply with Section 1.02 and need not be accompanied by an Opinion of Counsel)
stating that such Security has never been issued and sold by the Company, for
all purposes of this Indenture such Security shall be deemed not to have been
authenticated and delivered hereunder and shall never be entitled to the
benefits of this Indenture.

        Section 3.04. Registration, Registration of Transfer and Exchange. The
Company shall cause to be kept at the Corporate Trust Office of the Trustee or
in any office or agency of the Company in a Place of Payment a register for the
Securities (the "SECURITY REGISTER") in which, subject to such reasonable
regulations as it may prescribe, the Company shall provide for the registration
of the Securities and of transfers of the Securities. The Security Register
shall be in written form or any other form capable of being converted into
written form within a reasonable time. The Trustee, at its Corporate Trust
Office, is hereby appointed "SECURITY REGISTRAR" for the purpose of registering
the Securities and transfers of the Securities on such Security Register as
herein provided. In the event that the Trustee shall cease to be Security
Registrar, it shall have the right to examine the Security Register at all
reasonable times.

        Subject to the provisions of this Section 3.04 and except as otherwise
provided in any Security including any legend thereon, upon surrender for
registration of transfer of any Security at any office or agency of the Company
in a Place of Payment, 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, bearing a number not contemporaneously
outstanding, and containing identical terms and provisions.

        Subject to the provisions of this Section 3.04, at the option of the
Holder, the Securities may be exchanged for other Securities, of any authorized
denomination or denominations and of a like aggregate principal amount,
containing identical terms and provisions, upon surrender of the Securities to
be exchanged at any such office or agency. Whenever any such 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.

        Notwithstanding the foregoing, any global Security shall be exchangeable
only as provided in this paragraph. The depositary for the global Securities
shall be DTC, and the global Securities may be transferred, in whole but not in
part, only to a nominee of DTC, or by a nominee of DTC to DTC, or to a successor
to DTC for such global Security selected or approved by the Company or to a
nominee of such successor to DTC. If at any time DTC notifies the Company that
it is unwilling or unable to continue as depositary for the applicable global
Security or Securities or if at any time DTC ceases to be a clearing agency
registered under the Securities Exchange Act of 1934 if so required by
applicable law or regulation, the Company shall appoint a successor depositary
with respect to such global Security or Securities. If (x) a

                                      -15-

<PAGE>   22

successor depositary for such global Security or Securities is not appointed by
the Company within 90 days after the Company receives such notice or becomes
aware of such unwillingness, inability or ineligibility, (y) an Event of Default
has occurred and is continuing and the beneficial owners representing a majority
in principal amount of the applicable Securities represented by such global
Security or Securities advise DTC to cease acting as depositary for such global
Security or Securities or (z) the Company, in its sole discretion, determines at
any time that all Outstanding Securities (but not less than all) issued or
issuable in the form of one or more global Securities shall no longer be
represented by such global Security or Securities, then the Company shall
execute, and the Trustee shall authenticate and deliver, definitive Securities
of like rank, tenor and terms in definitive form in an aggregate principal
amount equal to the principal amount of such global Security or Securities. If a
Security is issued in exchange for any portion of a global Security after the
close of business at the office or agency where such exchange occurs on (i) any
Regular Record Date and before the opening of business at such office or agency
on the relevant Interest Payment Date or (ii) any Special Record Date and the
opening of business at such office or agency on the related proposed date for
payment of Defaulted Interest, interest or Defaulted Interest, as the case may
be, will not be payable on such Interest Payment Date or proposed date for
payment, as the case may be, in respect of such Security, but will be payable on
such Interest Payment Date or proposed date for payment, as the case may be,
only to the Person to whom interest in respect of such portion of such global
Security is payable in accordance with the provisions of this Indenture.

        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 or redemption shall (if so required by the Company or the Security
Registrar) 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 11.07 or 12.03(f) not involving any transfer.

        The Company or the Trustee, as applicable, shall not be required (i) to
issue, register the transfer of or exchange any Security if such Security may be
among those selected for redemption during a period beginning at the opening of
business 15 days before the day of mailing of the relevant notice of redemption
and ending at the close of business on the day of the mailing of the relevant
notice of redemption or (ii) to register the transfer of or exchange any
Security so selected for redemption in whole or in part, except, in the case of
any Security to be redeemed in part, the portion thereof not to be redeemed, or
(iii) to issue, register the transfer of or exchange any Security which has been
surrendered for repayment at the option of the Holder, except the portion, if
any, of such Security not to be so repaid.

                                      -16-

<PAGE>   23

        Section 3.05. Mutilated, Destroyed, Lost and Stolen Securities. If any
mutilated Security is surrendered to the Trustee or the Company, together with
such security or indemnity as may be required by the Company or the Trustee to
save each of them or any agent of either of them harmless, the Company shall, at
the relevant Holder's expense, execute and the Trustee shall authenticate and
deliver in exchange therefor a new Security of the same principal amount,
containing identical terms and provisions and bearing a number not
contemporaneously outstanding.

        If there shall be delivered to the Company and to the Trustee (i)
evidence to their satisfaction of the destruction, loss or theft of any Security
and (ii) such security or indemnity as may be required by them to save each of
them and any agent of either of them harmless, then, in the absence of notice to
the Company or the Trustee that such Security has been acquired by a bona fide
purchaser, the Company, at the relevant Holder's expense, 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 the same principal amount,
containing identical terms and provisions and bearing a number not
contemporaneously outstanding, appertaining to such destroyed, lost or stolen
Security.

        Notwithstanding the provisions of the previous two paragraphs, 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 3.06. Payment of Interest, Interest Rights Preserved. Interest
on any Security that 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 at the office or agency of
the Company maintained for such purpose pursuant to Section 10.02; provided,
however, that each installment of interest on any Security may at the Company's
option be paid by (i) mailing a check for such interest, payable to or upon the
written order of the Person entitled thereto pursuant to Section 3.07, to the
address of such Person as it appears on the Security Register or (ii) transfer
to an account maintained by the payee located inside the United States;
provided, however, that payments to DTC will be made by wire transfer of
immediately

                                      -17-

<PAGE>   24

available funds to the account of DTC or its nominee. The term "REGULAR RECORD
DATE" with respect to any Interest Payment Date shall mean the __________ or
__________ preceding __________ or __________, respectively.

        Any interest on any Security that 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 registered Holder thereof
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 3.06(a) or 3.06(b) below:

        (a) 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 (which shall not be less than 30 days after such notice is
received by the Trustee) and at the same time the Company shall deposit with the
Trustee an amount of money equal to the aggregate amount proposed to be paid in
respect of such Defaulted Interest or shall make arrangements satisfactory to
the Trustee for such deposit on or 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. The Trustee shall promptly notify the Company
of such Special Record Date and, in the name and at the expense of the Company,
shall cause notice of the proposed payment of such Defaulted Interest and the
Special Record Date therefor to be mailed, first-class postage prepaid, to each
Holder of Securities at his address as it appears in the Security Register not
less than 10 days prior to such Special Record Date. The Trustee may, in its
discretion, in the name and at the expense of the Company, cause a similar
notice to be published at least once in an Authorized Newspaper in each Place of
Payment, but such publications shall not be a condition precedent to the
establishment of such Special Record Date. Notice of the proposed payment of
such Defaulted Interest and the Special Record Date therefor having been mailed
as aforesaid, 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 (b).

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

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

                                      -18-

<PAGE>   25

        Section 3.07. 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 Sections 3.04 and 3.06)
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.

        None of the Company, the Trustee, any Paying Agent or the Security
Registrar will have any responsibility or liability for any aspect of the
records relating to or payments made on account of beneficial ownership
interests of a Security in global form or for maintaining, supervising or
reviewing any records relating to such beneficial ownership interests.

        Notwithstanding the foregoing, with respect to any global Security,
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 any depositary, as a Holder, with respect to
such global Security or impair, as between such depositary and owners of
beneficial interests in such global Security, the operation of customary
practices governing the exercise of the rights of such depositary (or its
nominee) as Holder of such global Security.

        Section 3.08. Cancellation. All Securities surrendered for payment,
redemption, repayment at the option of the Holder, registration of transfer or
exchange or for credit against any sinking fund payment shall, if surrendered to
any Person other than the Trustee, be delivered to the Trustee, and any such
Securities surrendered directly to the Trustee for any such purpose shall be
promptly canceled by it; provided, however, where the Place of Payment is
located outside of the United States, the Paying Agent at such Place of Payment
may cancel the Securities surrendered to it for such purposes prior to
delivering the Securities to the Trustee. The Company may at any time deliver to
the Trustee for cancellation any Securities previously authenticated and
delivered hereunder which the Company may have acquired in any manner
whatsoever, and may deliver to the Trustee (or to any other Person for delivery
to the Trustee) for cancellation any Securities previously authenticated
hereunder which the Company has not issued and sold, and all Securities so
delivered shall be promptly canceled by the Trustee. If the Company shall so
acquire any of the Securities, however, such acquisition shall not operate as a
redemption or satisfaction of the indebtedness represented by such Securities
unless and until the same are surrendered to the Trustee for cancellation. 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. Canceled Securities held by the Trustee shall be destroyed by the
Trustee and the Trustee shall deliver a certificate of such destruction to the
Company, unless by a Company Order the Company directs their return to it.

        Section 3.09 Computation of Interest. Interest on the Securities shall
be computed on the basis of a 360-day year consisting of twelve 30-day months.

                                      -19-

<PAGE>   26

                                    ARTICLE 4
                           SATISFACTION AND DISCHARGE

        Section 4.01. Satisfaction and Discharge of Indenture. This Indenture
shall upon Company Request cease to be of further effect with respect to any
Security specified in such Company Request (except as to any surviving rights of
conversion, registration of transfer or exchange of Securities herein expressly
provided for), and the Trustee, upon receipt of a Company Order, and at the
expense of the Company, shall execute proper instruments acknowledging
satisfaction and discharge of this Indenture when:

        (a)     either:
               (i) all Securities theretofore authenticated and delivered have
               been delivered to the Trustee for cancellation; or
               (ii) all Securities not theretofore delivered to the Trustee for
               cancellation:
                      (A) have become due and payable, or
                      (B) will become due and payable at their Stated Maturity
               within one year, or
                      (C) if redeemable at the option of the Company, 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 (A), (B) or (C) above, has irrevocably deposited
or caused to be deposited with the Trustee as trust funds in trust (1) an amount
of money, (2) Government Obligations that 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 (3) a combination thereof, sufficient in each case 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;

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

        (c) 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, the
obligations of the Company to the Trustee and any predecessor Trustee under
Section 6.07, and, if money shall have been deposited with and held by the
Trustee pursuant to Section 4.01(a)(ii), the obligations of the Trustee under
Section 4.02 and the last paragraph of Section 10.03 shall survive.

        Section 4.02. Application of Trust Funds. Subject to the provisions of
the last paragraph of Section 10.03, all amounts deposited with the Trustee
pursuant to Section 4.01 shall be held in trust and applied by it, in accordance
with the provisions of the Securities and this Indenture,

                                      -20-

<PAGE>   27

to the payment, either directly or through any Paying Agent (including the
Company acting as its own Paying Agent), as the Trustee may determine, to the
Persons entitled thereto, of the principal (and premium, if any) and any
interest for whose payment such amounts have been deposited with or received by
the Trustee, but such amounts need not be segregated from other funds except to
the extent required by law. All moneys deposited with the Trustee pursuant to
Section 4.01 (and held by it or any Paying Agent) for the payment of Securities
subsequently converted shall be returned to the Company upon Company Request.

                                    ARTICLE 5
                                    REMEDIES

        Section 5.01. Events of Default. "EVENT OF DEFAULT," wherever used
herein with respect to the Securities, means any one of the following events
(whatever the reason for such Event of Default and whether or not it shall be
occasioned by the provisions of Article 14 or 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):

        (a) default in the payment of any interest upon any Security, when such
interest becomes due and payable, and continuance of such default for a period
of 30 days (whether or not such payment is prohibited by the provisions of
Article 14); or

        (b) default in the payment of (i) the principal of (or premium, if any,
on) any Security when it becomes due and payable at its Maturity, or (ii) the
payment of the Redemption Price (including the Make-Whole Payment, if any) with
respect to any Security when it becomes due and payable (whether or not such
payment is prohibited by the provisions of Article 14); or

        (c) default in the payment of the Repurchase Price in respect of any
Security on the Repurchase Date therefor (whether or not such payment is
prohibited by the provisions of Article 14 hereof); or

        (d) failure by the Company to deliver shares of Common Stock (together
with cash in lieu of fractional shares) when such Common Stock (or cash in lieu
of fractional shares) is required to be delivered following conversion of a
Security and continuation of such default for a period of 10 days; or

        (e) default in the performance, or breach, of any covenant or warranty
of the Company in this Indenture with respect to any Security (other than a
covenant or warranty a default in whose performance or whose breach is elsewhere
in this Section specifically dealt with) 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 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

        (f) a default under any bonds, debentures, notes or other evidences of
indebtedness for money borrowed of the Company or under any mortgages,
indentures or instruments under which there may be issued or by which there may
be secured or evidenced any indebtedness for

                                      -21-

<PAGE>   28

money borrowed by the Company, whether such indebtedness now exists or shall
hereafter be created, which indebtedness, individually or in the aggregate, has
a principal amount outstanding in excess of $10,000,000, which default shall
have resulted in such indebtedness becoming or being declared due and payable
prior to the date on which it would otherwise have become due and payable,
without such indebtedness having been discharged, or such acceleration having
been rescinded or annulled, within a period of 30 days after there shall have
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
of the Securities then Outstanding, a written notice specifying such default and
requiring the Company to cause such indebtedness to be discharged or cause such
acceleration to be rescinded or annulled and stating that such notice is a
"Notice of Default" hereunder (unless such default has been cured or waived); or

        (g) the Company or any Significant Subsidiary pursuant to or within the
meaning of any Bankruptcy Law:

               (i)    commences a voluntary case,

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

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

               (iv) makes a general assignment for the benefit of its creditors;
or

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

               (i)    is for relief against the Company or any Significant
        Subsidiary in an involuntary case,

               (ii) appoints a Custodian of the Company or any Significant
        Subsidiary or for all or substantially all of the property of any of
        them, or

               (iii) orders the winding up or liquidation of the Company or any
        Significant Subsidiary,

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

        As used in this Section 5.01, the term "BANKRUPTCY LAW" means title 11,
U.S. Code or any similar Federal or State law for the relief of debtors and the
term "CUSTODIAN" means any receiver, trustee, assignee, liquidator or other
similar official under any Bankruptcy Law.

        Section 5.02. Acceleration of Maturity; Rescission and Annulment. If an
Event of Default with respect to Securities at the time Outstanding occurs and
is continuing, then and in every such case the Trustee or the Holders of not
less than 25% in principal amount of the Outstanding Securities may declare the
principal 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 the Holders), and upon
any such declaration such principal shall become immediately due and payable. If
an

                                      -22-

<PAGE>   29

Event of Default specified in Section 5.01(g) or 5.01(h) occurs, the principal
of, and accrued interest on, all the Securities shall automatically, and without
any declaration or other action on the part of the Trustee or any Holder, become
immediately due and payable.

        At any time after such a declaration of acceleration with respect to
Securities 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 of the Outstanding
Securities, by written notice to the Company and the Trustee, may rescind and
annul such declaration and its consequences if:

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

                      (i)    all overdue installments of interest on all
               Outstanding Securities,

                      (ii) the principal of (and premium, if any, on) any
               Outstanding Securities which have become due otherwise than by
               such declaration of acceleration and interest thereon at the rate
               or rates borne by or provided for in such Securities,

                      (iii) to the extent that payment of such interest is
               lawful, interest upon overdue installments of interest at the
               rate or rates borne by or provided for in such Securities, and

                      (iv) 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

        (b) all Events of Default with respect to Securities, other than the
nonpayment of the principal of (or premium, if any) or interest on Securities
which have become due solely by such declaration of acceleration, have been
cured or waived as provided in Section 5.13.

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

        Section 5.03.  Collection of Indebtedness and Suits for Enforcement by
Trustee. The Company covenants that if:

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

               (b)     default is made in the payment of the principal of (or
        premium, if any, on) any Security at its Maturity,

then 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, with
interest upon any overdue principal (and premium, if any) and, to the extent
that payment of such interest shall be legally enforceable,

                                      -23-

<PAGE>   30

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

        If an Event of Default with respect to Securities occurs and is
continuing, the Trustee may in its discretion proceed to protect and enforce its
rights and the rights of the Holders of Securities 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.

        Section 5.04. Trustee May File Proofs of Claim. In case of the pendency
of any receivership, insolvency, liquidation, bankruptcy, reorganization,
arrangement, adjustment, composition or other judicial proceeding relative to
the Company or any other obligor upon the Securities or the property of the
Company or of such other obligor or their creditors, the Trustee (irrespective
of whether the principal of the Securities shall then be due and payable as
therein expressed or by declaration or otherwise and irrespective of whether the
Trustee shall have made any demand on the Company for the payment of overdue
principal, premium, if any, or interest) shall be entitled and empowered, by
intervention in such proceeding or otherwise:

        (a) to file and prove a claim for the whole amount, or such lesser
        amount as may be provided for in the Securities, of principal (and
        premium, if any) and interest, owing and unpaid in respect of the
        Securities and to file such other papers or documents as may be
        necessary or advisable in order to have the claims of the Trustee
        (including any claim for the reasonable compensation, expenses,
        disbursements and advances of the Trustee, its agents and counsel) and
        of the Holders allowed in such judicial proceeding, and

        (b) 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 directed by
each Holder of Securities to make such payments to the Trustee, and in the event
that the Trustee shall request the making of such payments directly to the
Holders, to pay to the Trustee any amount due to it for the reasonable
compensation, expenses, disbursements and advances of the Trustee and any
predecessor Trustee, their agents and counsel, and any other amounts due the
Trustee or any predecessor Trustee under Section 6.07.

                                      -24-

<PAGE>   31

        Nothing herein contained shall be deemed to authorize the Trustee to
authorize or consent to or accept or adopt on behalf of any Holder of a
Security, 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 of a Security 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 5.05. Trustee May Enforce Claims Without Possession of
Securities. All rights of action and claims under this Indenture or any of 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 5.06. 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, or both, as the case may be, 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 and any predecessor
Trustee under Section 6.07;

        SECOND: To the holders of Senior Indebtedness to the extent required by
the provisions of Article 14.

        THIRD: To the payment of the amounts then due and unpaid upon the
Securities for principal (and premium, if any) and interest payable, 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 aggregate amounts
due and payable on such Securities for principal (and premium, if any) and,
interest, respectively; and

        FOURTH: To the payment of the remainder, if any, to the Company.

        Section 5.07. Limitation of 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:

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

        (b) the Holders of not less than 25% in principal amount 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;

                                      -25-

<PAGE>   32

        (c) such Holder or Holders have offered to the Trustee security or
indemnity reasonably satisfactory to the Trustee against the costs, expenses and
liabilities to be incurred in compliance with such request;

        (d) the Trustee for 60 days after its receipt of such notice, request
and offer of security or indemnity has failed to institute any such proceeding;
and

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

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

        Section 5.08. Unconditional Right of Holders to Receive Principal,
Premium, If Any, 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,
including the Redemption Prices and Make-Whole Payment upon redemption pursuant
to Article 11, and (subject to Sections 3.04 and 3.06) interest on such Security
on the respective due dates expressed in such Security (or, in the case of
redemption or repurchase, on the Redemption Date or Repurchase Date, as the case
may be) and to convert such Security in accordance with the provisions of this
Indenture and to institute suit for the enforcement of any such payment and
right to convert, and such rights shall not be impaired without the consent of
such Holder.

        Section 5.09. Restoration of Rights and Remedies. If the Trustee or any
Holder of a Security 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, the Company, the Trustee and the
Holders of Securities shall, subject to any determination in such proceeding, 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 5.10. 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 3.05, no right or
remedy herein conferred upon or reserved to the Trustee or to the Holders of
Securities 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.

                                      -26-

<PAGE>   33

        Section 5.11. 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 of Securities, as the case may be.

        Section 5.12. Control by Holders of Securities. The Holders of not less
than a majority in principal amount of the Outstanding Securities shall have the
right to direct the time, method and place of conducting any proceeding for any
remedy available to the Trustee or exercising any trust or power conferred on
the Trustee with respect to the Securities, provided that:

        (a) such direction shall not be in conflict with any rule of law or with
this Indenture,

        (b) the Trustee may take any other action deemed proper by the Trustee
which is not inconsistent with such direction, and

        (c) the Trustee need not take any action which might involve it in
personal liability or be unduly prejudicial to the Holders of Securities not
joining therein.

        Section 5.13. Waiver of Past Defaults. The Holders of not less than a
majority in principal amount of the Outstanding Securities may on behalf of the
Holders of all the Securities waive any past default hereunder with respect to
such Securities and its consequences, except a default:

        (a) in the payment of the principal of (or premium, if any) or  interest
on any Security,

        (b) in respect of the conversion by the Company of any Security into
Common Stock,

        (c) in the payment of the Redemption Prices or Make-Whole Payment
pursuant to Article 11,

        (d) in the payment of the Repurchase Price pursuant to Article 12, or

        (e) in respect of a covenant or provision hereof which under Article 9
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 Event of Default or impair any right consequent thereon.

        Section 5.14. Waiver of Usury, 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

                                      -27-

<PAGE>   34

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.

        Section 5.15. Undertaking for Costs. All parties to this Indenture
agree, and each Holder of any Security by his acceptance thereof shall be deemed
to have agreed, that any court may in its discretion require, in any suit for
the enforcement of any right or remedy under this Indenture, or in any suit
against the Trustee for any action taken or omitted by it as Trustee, the filing
by any party litigant in such suit of any undertaking to pay the costs of such
suit, and that such court may in its discretion assess reasonable costs,
including reasonable attorneys' fees, against any party litigant in such suit
having due regard to the merits and good faith of the claims or defenses made by
such party litigant; but the provisions of this Section shall not apply to any
suit instituted by the Trustee, to any suit instituted by any Holder, or group
of Holders, holding in the aggregate more than 10% in principal amount of the
Outstanding Securities, or to any suit instituted by any Holder for the
enforcement of the payment of the principal of (or premium, if any) or interest
on any Security on or after the respective Stated Maturities expressed in such
Security (or, in the case of redemption or repurchase, on or after the
Redemption Date or the Repurchase Date, respectively), or the right to convert
any Security in accordance with Article 13.

                                    ARTICLE 6
                                   THE TRUSTEE

        Section 6.01. General. The duties and responsibilities of the Trustee
shall be as provided by the TIA and as set forth herein. 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 the Trustee in its sole discretion shall believe that repayment of
such funds or adequate indemnity against such risk or liability is not
reasonably assured to it. Whether or not herein 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 Article 6.

        Section 6.02. Certain Rights of Trustee. Subject to TIA Sections 315(a)
through (d):

        (a) the Trustee may rely, and shall be protected in acting or refraining
from acting, upon any resolution, certificate, statement, instrument, facsimile
transmission, 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, made or presented by the
proper person and may accept and rely upon the same as conclusive evidence of
the truth and accuracy of the statement and opinions contained therein. The
Trustee need not investigate any fact or matter stated in any such document;

        (b) before the Trustee acts or refrains from acting, it may require an
Officers' Certificate or an Opinion of Counsel, which shall conform to Section
1.02. The Trustee shall not

                                      -28-

<PAGE>   35

be liable for any action it takes or omits to take in good faith in reliance on
such certificate or opinion;

        (c) the Trustee may consult with counsel and the written advice of such
counsel shall be full and complete authorization and protection with respect to
any action taken, suffered or omitted by it hereunder in good faith and reliance
thereon and may act through its attorneys and agents and shall not be
responsible for the misconduct or negligence of any attorney or agent appointed
with due care;

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

        (e) the Trustee shall not be liable for any action it takes or omits to
take in good faith that it believes to be authorized or within its rights or
powers or for any action it takes or omits to take in accordance with the
written direction of the holders of a majority in principal amount of the
Outstanding Securities relating to the time, method and place of conducting any
proceeding for any remedy available to the Trustee, or exercising any trust or
power conferred upon the Trustee, under this Indenture;

        (f) 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;

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

        (h) the Trustee shall not be required to take notice or be deemed to
have notice of any default hereunder unless the Trustee be specifically notified
of such default in writing by the Company or any holder of the Securities, and
in the absence of such notice the Trustee may conclusively assume that there is
no default; provided that if the Trustee is acting as Paying Agent, the Trustee
shall be required to take and be deemed to have notice of its failure to receive
payments of interest or principal hereunder;

        (i) except for information provided by the Trustee concerning the
Trustee, the Trustee shall have no responsibility with respect to any
information in any offering memorandum or other disclosure material distributed
with respect to the Securities, and the Trustee shall have no responsibility for
compliance with securities laws in connection with the issuance and sale of the
Securities;

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<PAGE>   36

        (j) in the event the Trustee shall receive inconsistent or conflicting
requests and indemnity from two or more groups of holders of the Securities,
each representing at least 25% (but less than 50%) of the aggregate principal
amount of the Securities then outstanding, the Trustee will act in accordance
with instructions received by the holders of the greater percentage thereof;

        (k) except as otherwise expressly provided by the provisions of this
Indenture, the Trustee shall not be obligated and may not be required to give or
furnish any notice, demand, report, request, reply, statement, advice or opinion
to the holder of any Security or to the Company or any other Person, and the
Trustee shall not incur any liability for its failure or refusal to give or
furnish the same unless obligated or required to do so by the express provisions
hereof; and

        (l) the Trustee shall not be required to give any bond or surety with
respect to the performance of its duties or the exercise of its powers under
this Indenture.

        Section 6.03. Individual Rights of Trustee. The Trustee, any Paying
Agent, 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 may
otherwise deal with the Company, its Subsidiaries or its Affiliates with the
same rights it would have if it were not the Trustee, Paying Agent, Security
Registrar or such other agent. Any registrar, co-registrar, paying agent,
conversion agent or authenticating agent may do the same with like rights.
However, the Trustee is subject to TIA Sections 310(b) and 311.

        Section 6.04. Trustee's Disclaimer. The Trustee (i) makes no
representation as to the validity or adequacy of this Indenture or the
Securities, (ii) shall not be accountable for the Company's use or application
of the proceeds from the Securities and (iii) shall not be responsible for any
statement in the Securities other than its certificate of authentication.

        Section 6.05. Notice of Default. If any Event of Default occurs and is
continuing and if the Trustee has actual knowledge of such Event of Default, the
Trustee shall mail to each holder in the manner and to the extent provided in
TIA Section 313(c) notice of the Event of Default within 90 days after it
occurs, unless such Event of Default has been cured or waived; provided,
however, that, except in the case of a default in the payment of the principal
of (or premium, if any) or interest on any Security, the Trustee shall be
protected in withholding such notice if and so long as Responsible Officers of
the Trustee in good faith determine that the withholding of such notice is in
the interests of the Holders of the Securities. For the purpose of this Section,
the term "DEFAULT" means any event which is, or after notice or lapse of time or
both would become, an Event of Default with respect to the Securities.

        Section 6.06. Conflicting Interests of Trustee. If the Trustee has or
shall acquire a conflicting interest within the meaning of the TIA, 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 TIA and this Indenture.

        Section 6.07. Compensation and Indemnity. The Company shall pay to the
Trustee such compensation as shall be agreed upon in writing for its services.
The compensation of the

                                      -30-

<PAGE>   37

Trustee shall not be limited by any law on compensation of a trustee of an
express trust. The Company shall reimburse the Trustee upon request for all
reasonable out-of-pocket expenses and advances incurred or made by the Trustee
in accordance with this Indenture. Such expenses shall include the reasonable
compensation and expenses of the Trustee's agents and counsel.

        The Company shall indemnify and hold harmless the Trustee and its
directors, agents and employees (collectively the "Indemnitees") against any and
all losses, liabilities, obligations, damages, penalties, fines, judgments,
actions, suits, proceedings, reasonable costs and expenses (including reasonable
fees and disbursements of counsel) of any kind whatsoever which may be incurred
by or imposed on the Indemnitees or any of them arising out of or in connection
with the acceptance or administration of its duties under this Indenture;
provided, however, that the Company need not reimburse any expense or indemnify
against any loss, obligation, damage, penalty, fine, judgment, action, suit,
proceeding, reasonable cost or expense (including reasonable fees and
disbursements of counsel) of any kind whatsoever which may be incurred by
Indemnitees or any of them which results from the negligence or willful
misconduct of the Indemnitees or any of them. The Trustee shall notify the
Company promptly of any claim for which it may seek indemnity. Failure by the
Trustee to so notify the Company shall not relieve the Company of its
obligations hereunder, unless the Company is materially prejudiced thereby. The
Company shall defend the claim and the Trustee shall cooperate in the defense.
Unless otherwise set forth herein, the Indemnitees of any of them may have
separate counsel and the Company shall pay the reasonable fees and expenses of
such counsel. The Company need not pay for any settlement made without its
consent, which consent shall not be unreasonably withheld. The provisions of
this Section 6.07 shall survive the termination of this Indenture and the
resignation or removal of the Trustee for any reason.

        To secure the Company's payment obligations in this Section 6.07, the
Trustee shall have a lien prior to the Securities on all money or property held
or collected by the Trustee, in its capacity as Trustee, except money or
property held in trust to pay principal of, premium, if any, and interest on
particular Securities.

        If the Trustee incurs expenses or renders services after the occurrence
of an Event of Default specified in Section 5.01(g) or Section 5.01(h), the
expenses and the compensation for the services will be intended to constitute
expenses of administration under Title 11 of the United States Bankruptcy Code
or any applicable federal or state law for the relief of debtors.

        Section 6.08. Replacement of Trustee. A resignation or removal of the
Trustee and appointment of a successor Trustee shall become effective only upon
the successor Trustee's acceptance of appointment as provided in this Section
6.08.

        The Trustee may resign at any time by so notifying the Company in
writing at least thirty (30) days prior to the date of the proposed resignation.
The holders of a majority in principal amount of the Outstanding Securities may
remove the Trustee by so notifying the Trustee in writing and may appoint a
successor Trustee with the prior consent of the Company. The Company may remove
the Trustee if: (i) the Trustee is no longer eligible under Section 6.10; (ii)
the Trustee is adjudged a bankrupt or an insolvent; (iii) a receiver or other
public officer takes charge of the Trustee or its property; or (iv) the Trustee
becomes incapable of acting.

                                      -31-

<PAGE>   38

        If the Trustee resigns or is removed, or if a vacancy exists in the
office of Trustee for any reason, the Company shall promptly appoint a successor
Trustee. Within one year after the successor Trustee takes office, the holders
of a majority in principal amount of the Outstanding Securities may appoint a
successor Trustee to replace the successor Trustee appointed by the Company. If
the successor Trustee does not deliver its written acceptance required by the
next succeeding paragraph of this Section 6.08 within thirty (30) days after the
retiring Trustee resigns or is removed, the retiring Trustee, the Company or the
holders of a majority in principal amount of the Outstanding Securities may
petition any court of competent jurisdiction for the appointment of a successor
Trustee.

        A successor Trustee shall deliver a written acceptance of its
appointment to the retiring Trustee and to the Company. Immediately after the
delivery of such written acceptance, subject to the lien provided in Section
6.07, (i) the retiring Trustee shall transfer all property held by it as Trustee
to the successor Trustee, (ii) the resignation or removal of the retiring
Trustee shall become effective and (iii) the successor Trustee shall have all
the rights, powers and duties of the Trustee under this Indenture. A successor
Trustee shall mail notice of its succession to each holder.

        If the Trustee is no longer eligible under Section 6.10, any holder who
satisfies the requirements of TIA Section 310(b) may petition any court of
competent jurisdiction for the removal of the Trustee and the appointment of a
successor Trustee.

        The Company shall give notice of any resignation and any removal of the
Trustee and each appointment of a successor Trustee to all holders. Each notice
shall include the name of the successor Trustee and the address of its Corporate
Trust Office.

        Notwithstanding replacement of the Trustee pursuant to this Section
6.08, the Company's obligation under Section 6.07 shall continue for the benefit
of the retiring Trustee.

        Section 6.09. Successor Trustee by Merger, Etc. If the Trustee
consolidates with, merges or converts into, or transfers all or substantially
all of its corporate trust business to, another corporation or national banking
association, the resulting, surviving or transferee corporation or national
banking association without any further act shall be the successor Trustee with
the same effect as if the successor Trustee had been named as the Trustee
herein.

        Section 6.10. Eligibility. This Indenture shall always have a Trustee
who satisfies the requirements of TIA Section 310(a)(1). The Trustee (or the
bank holding company to which the Trustee is a member) shall have a combined
capital and surplus of at least $25 million as set forth in its most recent
published annual report of condition.

        Section 6.11. Money Held in Trust. Subject to the provisions of Section
10.03 and Section 14.02, all monies received by the Trustee shall, until used or
applied as herein provided, be held in trust for the purposes for which they
were received. The Trustee shall not be liable for interest on any money
received by it except as the Trustee may agree with the Company. Money held in
trust by the Trustee need not be segregated from other funds except to the
extent required by law and except for money held in trust under Article 4 of
this Indenture.

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<PAGE>   39

        Section 6.12. Withholding Taxes. The Trustee, as agent for the Company,
shall exclude and withhold from each payment of principal and interest and other
amounts due hereunder or under the Securities any and all withholding taxes
applicable thereto as required by law. The Trustee agrees to act as such
withholding agent and, in connection therewith, whenever any present or future
taxes or similar charges are required to be withheld with respect to any amounts
payable in respect of the Securities, to withhold such amounts and timely pay
the same to the appropriate authority in the name of and on behalf of the
holders of the Securities, that it will file any necessary withholding tax
returns or statements when due, and that, as promptly as possible after the
payment thereof, it will deliver to each holder of a Security appropriate
documentation showing the payment thereof, together with such additional
documentary evidence as such holders may reasonably request from time to time.

        Section 6.13. Preferential Collection of Claims. 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 the claims against the Company (or any
such other obligor).

        Section 6.14. Trustee's Application for Instructions from the Company.
Any application by the Trustee for written instructions from the Company (other
than with regard to any action proposed to be taken or omitted to be taken by
the Trustee that affects the rights of the Holders of the Securities or holders
of Senior Indebtedness under this Indenture, including, without limitation,
under Article 14 hereof) may, at the option of the Trustee, set forth in writing
any action proposed to be taken or omitted by the Trustee under this Indenture
and the date on and/or after which such action shall be taken or such omission
shall be effective. The Trustee shall not be liable for any action taken by, or
omission of, the Trustee in accordance with a proposal included in such
application on or after the date specified in such application (which date shall
not be less than ten (10) Business Days after the date any officer of the
Company actually receives such application, unless any such officer shall have
consented in writing to any earlier date) unless prior to taking any such action
(or the effective date in the case of an omission), the Trustee shall have
received written instructions in response to such application specifying the
action to be taken or omitted.

                                    ARTICLE 7
                HOLDERS' LISTS AND REPORTS BY TRUSTEE AND COMPANY

        Section 7.01. Disclosure of Names and Addresses of Holders. 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 Paying Agent nor
any Security Registrar shall be held accountable by reason of the disclosure of
any information as to the names and addresses of the Holders of Securities in
accordance with TIA Section 312, regardless of the source from which such
information was derived, and that the Trustee shall not be held accountable by
reason of mailing any material pursuant to a request made under TIA Section
312(b).

        Section 7.02. Reports by Trustee. Within 60 days after May 15 of each
year commencing with the first May 15 after the first issuance of Securities
pursuant to this Indenture, the Trustee shall transmit by mail to all Holders of
Securities as provided in TIA Section 313(c)

                                      -33-

<PAGE>   40

a brief report dated as of such May 15 if required by TIA Section 313(a). A copy
of each such report shall at the time of such transmission to Holders be filed
by the Trustee with each stock exchange upon which any Securities are listed
with the Commission and the Company. The Company will notify the Trustee when
any Securities are listed on any stock exchange and of any delisting thereof.

        Section 7.03. Reports by Company. The Company will:

        (a) file with the Trustee, within 15 days after the Company is required
to file the same with the Commission, copies of the annual reports and of the
information, documents and other reports (or copies of such portions of any of
the foregoing as the Commission may from time to time by rules and regulations
prescribe) which the Company may be required to file with the Commission
pursuant to Sections 13(a) or 13(b) or Section 15(d) of the Securities Exchange
Act of 1934; or, if the Company is not required to file information, documents
or reports pursuant to either of such Sections, then it will file with the
Trustee, in accordance with rules and regulations prescribed from time to time
by the Commission, such of the supplementary and periodic information, documents
and reports which may be required pursuant to Section 13 of the Securities
Exchange Act of 1934 in respect of a security listed and registered on a
national securities exchange as may be prescribed from time to time in such
rules and regulations;

        (b) file with the Trustee and the Commission, in accordance with rules
and regulations prescribed from time to time by the Commission, such additional
information, documents and reports with respect to compliance by the Company
with the conditions and covenants of this Indenture as may be required from time
to time by such rules and regulations; and

        (c) file with the Trustee and the Commission, if applicable, and
transmit by mail to the Holders of Securities, within 30 days after the filing
thereof with the Trustee, in the manner and to the extent provided in TIA
Section 313(c), such summaries of any information, documents and reports
required to be filed by the Company pursuant to paragraphs (1) and (2) of this
Section as may be required by rules and regulations prescribed from time to time
by the Commission and other information as may be required pursuant to the TIA
at the time and in the manner provided pursuant to such Act.

        Section 7.04. Company to Furnish Trustee Names and Addresses of
Holders. (a) The Company will furnish or cause to be furnished to the Trustee:

        (i) semi-annually, not later than 10 days after the Regular Record Date
        for interest for the Securities, a list, in such form as the Trustee may
        reasonably require, of the names and addresses of the Holders of
        Securities as of such Regular Record Date, or if there is no Regular
        Record Date for interest for the Securities, semi-annually, upon such
        dates as are set forth in the Board Resolution or indenture supplemental
        hereto; and

        (ii) 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,

                                      -34-

<PAGE>   41

provided, however, that, so long as the Trustee is the Security Registrar, no
such list shall be required to be furnished.

        (b) The Company shall provide the Trustee with at least 30 days' prior
notice of any change in location of its principal executive offices or other
principal place of business.

                                    ARTICLE 8
                CONSOLIDATION, MERGER, SALE, LEASE OR CONVEYANCE

        Section 8.01. Consolidations and Mergers of Company and Sales, Leases
and Conveyances Permitted Subject to Certain Conditions. The Company may
consolidate with, or sell, lease, transfer, convey or otherwise dispose of all
or substantially all of its assets to, or merge with or into any other Person,
provided that in any such case, (1) either the Company shall be the continuing
corporation, or the Person (if other than the Company) formed by such
consolidation or into which the Company is merged or the Person which acquires
or leases the Company's assets substantially as an entirety is a corporation,
partnership, limited liability company or trust organized and existing under the
laws of any United States jurisdiction and expressly assumes the due and
punctual payment of the principal of (and premium, if any) and any interest
payable pursuant to this Indenture on all of the Securities, according to their
tenor, and the due and punctual performance and observance of all of the
covenants and conditions of this Indenture to be performed by the Company and
shall have provided for conversion rights, if applicable, in accordance with the
provisions of Article 13 hereof, by supplemental indenture, complying with
Article 9 hereof, satisfactory to the Trustee, executed and delivered to the
Trustee by such corporation and (2) immediately after giving effect to such
transaction and treating any indebtedness which becomes an obligation of the
Company or such Person or any Subsidiary as a result thereof as having been
incurred by the Company or such Subsidiary at the time of such transaction, no
Event of Default, and no event which, after notice or the lapse of time, or
both, would become an Event of Default, shall have occurred and be continuing.

        Section 8.02. Rights and Duties of Successor Corporation. In case of any
such consolidation, merger, sale, lease or conveyance and upon any such
assumption by the successor Person, such successor Person shall succeed to and
be substituted for the Company, with the same effect as if it had been named
herein as the party of the first part, and the predecessor corporation, except
in the event of a lease, shall be relieved of any further obligation under this
Indenture and the Securities. Such successor Person thereupon may cause to be
signed, and may issue either in its own name or in the name of the Company, any
or all of the Securities issuable hereunder which theretofore shall not have
been signed by the Company and delivered to the Trustee; and, upon the order of
such successor corporation, instead of the Company, and subject to all the
terms, conditions and limitations in this Indenture prescribed, the Trustee
shall authenticate and shall deliver any Securities which previously shall have
been signed and delivered by the officers of the Company to the Trustee for
authentication, and any Securities which such successor Person thereafter shall
cause to be signed and delivered to the Trustee for that purpose. All the
Securities so issued shall in all respects have the same legal rank and benefit
under this Indenture as the Securities theretofore or thereafter issued in
accordance with the terms of this Indenture as though all of such Securities had
been issued at the date of the execution hereof.

                                      -35-

<PAGE>   42

        In case of any such consolidation, merger, sale, lease or conveyance,
such changes in phraseology and form (but not in substance) may be made in the
Securities thereafter to be issued as may be appropriate.

        Section 8.03. Officers' Certificate and Opinion of Counsel. Any
consolidation, merger, sale, lease, transfer, conveyance or other dispositions
permitted under Section 8.01 is also subject to the condition that the Trustee
receive an Officers' Certificate and an Opinion of Counsel to the effect that
any such consolidation, merger, sale, lease, transfer or conveyance or other
dispositions and the assumption by any successor Person, complies with the
provisions of this Article and that all conditions precedent herein provided for
relating to such transaction have been complied with.

                                    ARTICLE 9
                             SUPPLEMENTAL INDENTURES

        Section 9.01. Supplemental Indentures Without Consent of Holders.
Without the consent of any Holders of Securities, the Company, when authorized
by or pursuant to 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:

        (a) to evidence the succession of another Person to the Company and the
assumption by any such successor of the covenants of the Company contained
herein and the Securities issued hereunder;

        (b) to add to the covenants of the Company for the equal and ratable
benefit of the Holders of the Securities or to surrender any right, power or
option herein conferred upon the Company;

        (c) to add any additional Events of Default for the benefit of the
Holders of the Securities; provided, however, that in respect of any such
additional Events of Default such supplemental indenture may provide for a
particular period of grace after default (which period may be shorter or longer
than that allowed in the case of other defaults) or may provide for an immediate
enforcement upon such default or may limit the remedies available to the Trustee
upon such default or may limit the right of the Holders of a majority in
aggregate principal amount of those Securities to which such additional Events
of Default apply to waive such default;

        (d) to evidence and provide for the acceptance of appointment hereunder
by a successor Trustee with respect to the Securities and to add to or change
any of the provisions of this Indenture as shall be necessary to provide for or
facilitate the administration of the trusts hereunder by more than one Trustee;

        (e) to cure any ambiguity, to correct or supplement any provision herein
which may be defective or inconsistent with any other provision herein; provided
such provisions shall not adversely affect the interests of the Holders of
Securities in any material respect;

                                      -36-

<PAGE>   43

        (f) to make any change that does not adversely affect the rights of any
holder of Securities;

        (g) to make any change to comply with any requirement of the Commission
in connection with the qualification of the Indenture under TIA; or

        (h) to provide for the issuance of uncertificated Securities in addition
to or in place of certificated Securities; provided, however, that the
uncertificated Securities are issued in registered form for purposes of Section
163(f) of the Code or in a manner such that the uncertificated Securities are
described in Section 163(f)(2)(B) of the Code.

        Section 9.02. Supplemental Indentures with Consent of Holders. With the
consent of the Holders of not less than a majority in principal amount of all
Outstanding Securities, by Act of said Holders delivered to the Company and the
Trustee, the Company, when authorized by or pursuant to 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 of Securities under this Indenture; provided, however, that no
such supplemental indenture shall, without the consent of the Holder of each
Outstanding Security affected thereby:

        (a) reduce the principal amount, Repurchase Price or Redemption Price
with respect to any Security, or extend the Stated Maturity of any Security or
alter the manner of payment or rate of interest on any Security or make any
Security payable in money or securities other than that stated in the Security;

        (b) reduce the percentage in principal amount 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 with
respect to Securities (or compliance with certain provisions of this Indenture
or certain defaults hereunder and their consequences) provided for in this
Indenture;

        (c) make any change that adversely affects the right to convert any
Security;

        (d) modify the provisions of the Indenture relating to the ranking of
the Securities in a manner adverse to the Holders of the Securities; or

        (e) impair the right to institute suit for the enforcement of any
payment with respect to, or conversion of, the Securities.

        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 9.03. Execution of Supplemental Indentures. In executing, or
accepting the additional trusts created by, any supplemental indenture permitted
by this Article or the modification thereby of the trusts created by this
Indenture, the Trustee shall be entitled to receive, and (subject to Article 6)
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

                                      -37-

<PAGE>   44

Indenture. The Trustee may, but shall not be obligated to, enter into any such
supplemental indenture which affects the Trustee's own rights, duties or
immunities under this Indenture or otherwise.

        Section 9.04. 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 9.05. Conformity with Trust Indenture Act. Every supplemental
indenture executed pursuant to this Article shall conform to the requirements of
the Trust Indenture Act as then in effect.

        Section 9.06. 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 10
                                    COVENANTS

        Section 10.01. Payment of Principal, Premium, If Any, and Interest. The
Company covenants and agrees for the benefit of the Holders of Securities that
it will duly and punctually pay the principal of (and premium, if any), interest
on, and the Repurchase Price, the Redemption Price and the Make-Whole Payment
with respect to the Securities in accordance with the terms of the Securities
and this Indenture. At the option of the Company, all payments of principal may
be paid by check to the registered Holder of the Security or other person
entitled thereto against surrender of such Security. The conversion of any
Securities pursuant to Article 13 hereof, together with any cash payments
required to be made in accordance with the terms of the Securities and this
Indenture, will satisfy the Company's obligations under this Section 10.01 with
respect to such Securities.

        Section 10.02. Maintenance of Office or Agency. The Company shall
maintain an office or agency in the Borough of Manhattan, City of New York,
where the Securities may be presented or surrendered for payment or conversion
or redemption, where the 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 (a "Place of
Payment"). The Company will give prompt written notice to the Trustee of the
location, and any change in the location, of each 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

                                      -38-

<PAGE>   45

Corporate Trust Office of the Trustee, and the Company hereby appoints the
Trustee its agent to receive all such presentations, surrenders, notices and
demands.

        The Company may from time to time designate one or more other offices or
agencies where the Securities may be presented or surrendered for any or all of
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 accordance with the
requirements set forth above 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. The Company hereby
designates as a Place of Payment of the Securities the Corporate Trust Office of
the Trustee at ___________. The Company hereby initially appoints the Trustee as
Paying Agent and Conversion Agent as its agent to receive all such
presentations, surrenders, notice and demands.

        Section 10.03. Money for Securities Payments to Be Held in Trust. If the
Company shall at any time act as its own Paying Agent with respect to any
Securities, it will, on or before each due date of the principal of (and
premium, if any), or interest on 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 for the
Securities, it will, before each due date of the principal of (and premium, if
any), or interest on, the 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 in trust for the benefit of the Persons entitled to
such principal, premium or interest and (unless such Paying Agent is the
Trustee) the Company will promptly notify the Trustee 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:

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

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

        (c) at any time during the continuance of any Event of Default upon the
written request of the Trustee, forthwith pay to the Trustee all sums so held in
trust by such Paying Agent.

        The Company may at any time, for the purpose of obtaining the
satisfaction and discharge of this Indenture or for any other purpose, pay, or
by Company Order direct any Paying Agent to pay, to the Trustee all sums held in
trust by the Company or such Paying Agent,

                                      -39-

<PAGE>   46

such sums to be held by the Trustee upon the same trusts as those upon which
such sums were held by the Company or such Paying Agent; and, upon such payment
by any Paying Agent to the Trustee, such Paying Agent shall be released from all
further liability with respect to such sums.

        Except as otherwise provided in the Securities, 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 upon 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 of such principal of (and
premium, if any) or interest on any Security, without interest thereon, 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 an Authorized Newspaper, 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 10.04. Existence. Subject to Article 8, the Company will do or
cause to be done all things necessary to preserve and keep in full force and
effect its corporate existence, rights (charter and statutory) and franchises,
except to the extent that the Board of Directors shall determine that the
failure to do so would not have a material adverse effect on the business,
assets, financial condition or results of operation of the Company (a "MATERIAL
ADVERSE EFFECT"); provided, however, that the Company shall not be required to
preserve any right or franchise if the Board of Directors shall determine that
the preservation thereof is no longer desirable in the conduct of the business
of the Company and that the loss thereof is not disadvantageous in any material
respect to the Holders.

        Section 10.05. Payment of Taxes and Other Claims. The Company will pay
or discharge or cause to be paid or discharged, before the same shall become
delinquent, (1) all taxes, assessments and governmental charges levied or
imposed upon it or any Subsidiary or upon the income, profits or property of the
Company or any Subsidiary, 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 Subsidiary and have a Material Adverse Effect; 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 10.06. Statement as to Compliance. The Company will deliver to
the Trustee, within 120 days after the end of each fiscal year of the Company, a
certificate from the principal executive officer, principal financial officer or
principal accounting officer as to his or her knowledge of the Company's
compliance with all terms, conditions and provisions under this Indenture and,
in the event of any noncompliance, specifying such noncompliance and the nature
and status thereof. For purposes of this Section 10.06, such compliance shall be
determined without regard to any period of grace or requirement of notice under
this Indenture.

                                      -40-

<PAGE>   47

        Section 10.07. Waiver of Certain Covenants. The Company may omit in any
particular instance to comply with any term, provision or condition set forth in
Sections 10.04 to 10.05, inclusive, if before the time for such compliance the
Holders of at least a majority in principal amount of all outstanding
Securities, 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
term, provision or condition shall remain in full force and effect.

                                   ARTICLE 11
                            REDEMPTION OF SECURITIES

        Section 11.01. Provisional and Optional Redemption by the Company. (a)
The Securities may be redeemed at the election of the Company, as a whole or
from time to time in part, at any time prior to __________, 2003 (a "PROVISIONAL
REDEMPTION"), upon notice as set forth in Section 11.04, at a redemption price
equal to $1,000 per $1,000 principal amount of the Securities redeemed plus
accrued and unpaid interest, if any, to but excluding the date of redemption
(the "PROVISIONAL REDEMPTION DATE") if the Closing Price of the Common Stock has
exceeded 150% of the conversion price (as defined in Article 13) then in effect
for at least 20 Trading Days in any consecutive 30-Trading Day period ending on
the Trading Day prior to the date of mailing of the provisional notice of
redemption pursuant to Section 11.04 (the "NOTICE DATE").

        Upon any such Provisional Redemption, the Company shall make an
additional payment in cash (the "MAKE-WHOLE PAYMENT") with respect to the
Securities called for redemption to holders on the Notice Date in an amount
equal to $_____ per $1,000 principal amount of the Securities, less the amount
of any interest actually paid on such Securities prior to the Notice Date. The
Company shall make the Make-Whole Payment on all Securities called for
Provisional Redemption, including those Securities converted into Common Stock
between the Notice Date and the Provisional Redemption Date.

        (b) The Securities may be redeemed at the election of the Company, as a
whole or from time to time in part, at any time on or after __________, 2003,
and prior to maturity (an "OPTIONAL REDEMPTION"), upon notice as set forth in
Section 11.04, at the following optional redemption prices (expressed as
percentages of the principal amount), together in each case with accrued and
unpaid interest, if any, up to but not including the date fixed for redemption.

        The table below shows Redemption Prices with respect to $1,000 principal
amount of the Securities if redeemed during the twelve-month periods described
below:

        Period                                      Redemption Price

        __________, 2003 through __________, 2004         _____%

        Thereafter                                        _____%.

                                      -41-

<PAGE>   48

        Section 11.02. Election to Redeem; Notice to Trustee. The election of
the Company to redeem any Securities shall be evidenced by or pursuant to a
Board Resolution. In case of any redemption at the election of the Company of
all or any part of the Securities pursuant to Section 11.01 (Provisional
Redemption or Optional Redemption), the Company shall, at least 45 days prior to
the giving of the notice of redemption in Section 11.04 (unless a shorter notice
shall be satisfactory to the Trustee), notify the Trustee of the Redemption Date
and of the principal amount of Securities to be redeemed. In the case of any
redemption of Securities prior to the expiration of any restriction on such
redemption provided in the terms of such Securities or elsewhere in this
Indenture, the Company shall furnish the Trustee with an Officers' Certificate
evidencing compliance with such restriction.

        Section 11.03. Selection by Trustee of Securities to Be Redeemed. If
less than all the Securities are to be redeemed, the particular Securities to be
redeemed shall be selected not more than 60 days prior to the Redemption Date by
the Trustee, from the Outstanding Securities not previously called for
redemption, by lot, pro rata or by such other method as the Trustee shall deem
fair and appropriate.

        If any Security selected for partial redemption is converted in part
before termination of the conversion right with respect to the portion of the
Security so selected, the converted portion of such Security shall be deemed,
solely for purposes of determining the aggregate principal amount of the
Securities to be redeemed, to be the portion selected for redemption (provided,
however, that the Holder of such Security so converted and deemed redeemed shall
not be entitled to any additional interest payment as a result of such deemed
redemption than such Holder would have otherwise been entitled to receive upon
conversion of such Security). Securities which have been converted during a
selection of Securities to be redeemed may be treated by the Trustee as
Outstanding for the purpose of such selection.

        Securities in denominations of $1,000 may only be redeemed in whole. The
Trustee may select for redemption portions (equal to $1,000 or any multiple
thereof) of the principal of Securities that have denominations larger than
$1,000. Provisions of this Indenture that apply to Securities called for
redemption also apply to portions of Securities called for redemption.

        The Trustee shall promptly notify the Company and the Security Registrar
(if other than itself) 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, unless the context otherwise
requires, all provisions relating to the redemption of Securities shall relate,
in the case of any Security redeemed or to be redeemed only in part, to the
portion of the principal amount of such Security which has been or is to be
redeemed.

        Section 11.04. Notice of Redemption. Notice of redemption shall be given
in the manner provided in Section 1.06, not less than 30 days nor more than 60
days prior to the Redemption Date to each Holder of Securities to be redeemed,
but failure to give such notice in the manner herein provided to the Holder of
any Security designated for redemption as a whole or in part, or any defect in
the notice to any such Holder, shall not affect the validity of the proceedings
for the redemption of any other such Security or portion thereof.

                                      -42-

<PAGE>   49

        Any notice that is mailed to the Holders of Securities in the manner
herein provided shall be conclusively presumed to have been duly given, whether
or not the Holder receives the notice.

        All notices of redemption shall state:

               (a)    the Redemption Date;

               (b) the Redemption Price, accrued interest to the Redemption Date
        payable as provided in Section 11.06, if any, and, with respect to
        Securities called for Provisional Redemption, the Make-Whole Payment;

               (c) if less than all Outstanding Securities are to be redeemed,
        the identification (and, in the case of partial redemption, the
        principal amount) of the particular Securities to be redeemed;

               (d) in case any Security is to be redeemed in part only, the
        notice which relates to such Security shall state that on and after the
        Redemption Date, upon surrender of such Security, the holder will
        receive, without a charge, a new Security or Securities of authorized
        denominations for the principal amount thereof remaining unredeemed;

               (e) that on the Redemption Date, the Redemption Price and accrued
        interest to the Redemption Date payable as provided in Section 11.06, if
        any, and, with respect to Securities called for Provisional Redemption,
        the Make-Whole Payment, will become due and payable upon each such
        Security, or the portion thereof, to be redeemed and, if applicable,
        that interest thereon shall cease to accrue on and after said date;

               (f) the Place or Places of Payment where such Securities,
        maturing after the Redemption Date, are to be surrendered for payment of
        the Redemption Price and accrued interest, if any, and, with respect to
        Securities called for Provisional Redemption, the Make-Whole Payment, or
        for conversion,

               (g) that Securities called for redemption must be presented and
        surrendered to the Paying Agent to collect the redemption price;

               (h)    the then current Conversion Price;

               (i) that the Securities called for redemption may be converted at
        any time before the close of business on the Redemption Date;

               (j)    the CUSIP number of such Security, if any; and

               (k) that a Holder of Securities who desires to convert Securities
        must satisfy the requirements for conversion contained in such
        Securities.

        Notice of redemption of Securities to be redeemed 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.

                                      -43-

<PAGE>   50

        Section 11.05. Deposit of Redemption Price. Not later than 11:00 a.m.
New York City time on the 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 10.03) an amount of
money sufficient to pay on the Redemption Date, the Redemption Price of, and
(except if the Redemption Date shall be an Interest Payment Date) accrued
interest on, and, with respect to the Securities called for Provisional
Redemption, the Make-Whole Payment on, all the Securities or portions thereof
which are to be redeemed on that date, other than Securities or portions thereof
called for redemption on that date which have been delivered by the Company to
the Trustee for cancellation or have been converted; provided that, with respect
to a Provisional Redemption, any money so deposited for payment of the
Make-Whole Payment shall remain segregated and held in trust for payment of the
Make-Whole Payment which shall be made on all Securities called for Provisional
Redemption, including Securities converted into shares of Common Stock after the
Notice Date and prior to the Provisional Redemption Date.

        Section 11.06. 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 (together with accrued interest, if any, to the Redemption
Date), and from and after such date (unless the Company shall default in the
payment of the Redemption Price and accrued interest) such Securities shall, if
the same were interest-bearing, cease to bear interest. Upon surrender of any
such Security for redemption in accordance with said notice, such Security shall
be paid by the Company at the Redemption Price, together with accrued interest,
if any, to the Redemption Date and with respect to Securities called for
Provisional Redemption (including Securities converted into Common Stock
pursuant to the terms hereof after the Notice Date and prior to the Provisional
Redemption Date), the Make-Whole Payment; and provided, however, that if the
Provisional Redemption Date is an Interest Payment Date, the semi-annual payment
of interest becoming due on such date shall be payable to the Holders of such
Securities registered as such on the relevant Regular Record Date according to
their terms and the provisions of Section 3.06, and with respect to a
Provisional Redemption, the holder of any Securities converted into Common Stock
pursuant to the terms hereof after the Notice Date and prior to the Provisional
Redemption Date shall have the right to the Make-Whole Payment regardless of the
conversion of such Securities.

        If any Security called for redemption shall not be so paid upon
surrender thereof for redemption, the principal and premium, if any (including
the Make-Whole Payment, if any), shall, until paid, bear interest from the
Redemption Date at the rate borne by the Security and such Security shall remain
convertible into Common Stock until the principal and premium, if any (including
the Make-Whole Payment, if any), shall have been paid.

        Section 11.07. Securities Redeemed in Part. Any Security which is to be
redeemed only in part (pursuant to the provisions of this Article) shall be
surrendered at a Place of Payment therefor (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

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<PAGE>   51

aggregate principal amount equal to and in exchange for the unredeemed portion
of the principal of the Security so surrendered.

                                   ARTICLE 12
             REPURCHASE AT OPTION OF HOLDERS UPON CHANGE IN CONTROL

        Section 12.01. Right to Require Repurchase. In the event that a Change
in Control shall occur, each Holder shall have the right, at the Holder's
option, to require the Company to repurchase (subject to the provisions of
Section 14.03 hereof), and upon the exercise of such right the Company shall
repurchase, all of such Holder's Securities, or any portion of the principal
amount thereof that is an integral multiple of $1,000 (provided that no single
Security may be repurchased in part unless the portion of the principal amount
of such Security to be outstanding after such repurchase is equal to $1,000 or
an integral multiple of $1,000), on the date (the "REPURCHASE DATE") that is not
later than 45 Business Days after the date of the occurrence of a Change in
Control at a purchase price equal to 100% of the principal amount plus interest
accrued and unpaid to the Repurchase Date (subject to the right of Holders of
record on the Regular Record Date to receive interest on the relevant Interest
Payment Date) (the "REPURCHASE PRICE"). At the option of the Company, the
Repurchase Price may be paid in cash or, subject to the fulfillment by the
Company of the conditions set forth in Section 12.02, by delivery of shares of
Common Stock having a fair market value equal to the Repurchase Price as
described in Section 12.02. If the Repurchase Date is between a Regular Record
Date and the related Interest Payment Date, then the interest payable on such
Interest Payment Date shall be paid to the Holder of record of the Security on
such Regular Record Date.

        Section 12.02. Conditions to the Company's Election to Pay the
Repurchase Price in Common Stock.

        The Company may elect to pay the Repurchase Price by delivery of shares
of Common Stock pursuant to Section 12.01 if and only if the following
conditions have been satisfied:

        (a) The shares of Common Stock deliverable in payment of the Repurchase
Price shall have a fair market value as of the Repurchase Date of not less than
the Repurchase Price. For purposes of this Section 12.02, the fair market value
of shares of Common Stock shall be determined by the Company and shall be equal
to 95% of the average of the Closing Prices of the Common Stock for the five
consecutive Trading Days ending on and including the third Trading Day
immediately preceding the Repurchase Date;

        (b) The shares of Common Stock deliverable in payment of the Repurchase
Price shall be listed for trading on a U.S. national securities exchange or
approved for trading on an established automated over-the-counter trading market
in the United States, in either case, immediately prior to the Repurchase Date;
and

        (c) All shares of Common Stock deliverable in payment of the Repurchase
Price shall be issued out of the Company's authorized but unissued Common Stock
and will, upon issue, be duly and validly issued and fully paid and
non-assessable and free of any preemptive rights.

                                      -45-

<PAGE>   52

        If all of the conditions set forth in this Section 12.02 are not
satisfied in accordance with the terms thereof, the Repurchase Price shall be
paid by the Company only in cash.

        Section 12.03. Notices; Method of Exercising Repurchase Right, Etc. (a)
Unless the Company shall have theretofore called for redemption all of the
Outstanding Securities, on or before the 15th day after the occurrence of a
Change in Control, the Company or, at the written request of the Company, on or
before the tenth (10th) day after receipt of such request, the Trustee, at the
Company's expense, shall give notice to all Holders of the Securities and to
beneficial holders of Securities as required by applicable law (the "COMPANY
NOTICE") of the occurrence of the Change in Control and of the repurchase right
set forth herein arising as a result thereof. If the Company gives such notice
of a repurchase right, the Company shall also deliver a copy of such notice of a
repurchase right to the Trustee.

        Each Company Notice shall state:

        (i) the date of such Change in Control and, briefly, the events causing
        such Change in Control;

        (ii) the date by which the Change in Control Purchase Notice (as defined
        below) must be delivered;

        (iii)  the Repurchase Date;

        (iv) the Repurchase Price, and whether the Repurchase Price shall be
        paid by the Company in cash or by delivery of shares of Common Stock;

        (v) a description of the procedure which a Holder must follow to
        exercise a repurchase right;

        (vi) the procedures for withdrawing a Change in Control Purchase Notice;

        (vii) the place or places where such Securities are to be surrendered
        for payment of the Repurchase Price and accrued interest, if any;

        (viii) briefly, the conversion rights of Holders of Securities;

        (ix) the conversion price and any adjustments thereto, the date on which
        the right to convert the Securities will terminate and the places where
        such Securities may be surrendered for conversion;

        (x) that Holders who want to convert Securities must satisfy the
        requirements set forth in the Securities; and

        (xi) that no failure of the Company to give the foregoing notice or
defect therein shall limit any Holder's right to exercise a repurchase right or
affect the validity of the proceedings for the repurchase of the Securities.

                                      -46-

<PAGE>   53

        The Company will comply with the provisions of Rule 13e-4, Rule 14e-1
and any other tender offer rules under the Exchange Act which may be applicable,
and the Company will file a Schedule 13E-4 or any other schedule required under
the Exchange Act in connection with the Company's obligations under this Article
12.

        (b) To exercise a repurchase right, a Holder shall deliver to the Paying
Agent or an office or agency maintained by the Company for such purpose in the
Borough of Manhattan, The City of New York, prior to the close of business on or
before the Repurchase Date written notice of the Holder's exercise of such right
(the "CHANGE IN CONTROL PURCHASE Notice"), which notice shall set forth (i) the
name of the Holder, the principal amount of the Securities to be repurchased
(and, if any Security is to be repurchased in part, the portion of the principal
amount thereof to be repurchased and the name of the Person in which the portion
thereof to remain outstanding after such repurchase is to be registered) and a
statement that an election to exercise the repurchase right is being made
thereby pursuant to the applicable provisions of the Securities, and, in the
event that the Repurchase Price shall be paid in shares of Common Stock, the
name or names (with addresses) in which the certificate or certificates for
shares of Common Stock shall be issued, and (ii) the certificate numbers of the
Securities with respect to which the repurchase right is being exercised.

        (c) In the event a repurchase right shall be exercised in accordance
with the terms hereof, the Company shall pay or cause to be paid to the Paying
Agent the Repurchase Price in cash or shares of Common Stock, if shares of
Common Stock are to be issued, as provided above, for payment to the Holder on
the Repurchase Date with respect to the Securities (or portion thereof) as to
which the repurchase right has been exercised; provided, however, that such
Security for which a repurchase right has been exercised has been delivered to
the Paying Agent at any time after the notice of exercise of a repurchase right
shall have been given. Payment of the Repurchase Price for such Security shall
be made promptly following the later of the Business Day following the
Repurchase Date and time of delivery of the Security. If the Paying Agent holds
money sufficient to pay the Repurchase Price on the Business Day following the
Repurchase Date, then, immediately after the Repurchase Date, such Security
shall cease to be outstanding and interest will cease to accrue and will be
deemed paid regardless of whether such Security has been delivered to the Paying
Agent, and all other rights of the Holder shall terminate (other than the right
of such Holder to receive the Repurchase Price upon delivery of such Security).

        (d) On or prior to the Repurchase 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 10.03 of the
Indenture) an amount of money sufficient to pay the Repurchase Price of the
Securities which are to be repaid on the Repurchase Date.

        (e) If any Security (or portion thereof) surrendered for repurchase
shall not be so paid on the Business Day following the Repurchase Date, the
principal amount of such Security (or portion thereof, as the case may be)
shall, until paid, bear interest from the Repurchase Date at the rate of _____%
per annum, and each Security shall remain convertible into Common Stock in
accordance with Article 13 herein until the principal of such Security (or
portion thereof, as the case may be) shall have been paid or duly provided for.

                                      -47-

<PAGE>   54

        (f) Any Security which is to be repurchased only in part shall be
surrendered to the Trustee (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, containing identical terms and conditions,
each in an authorized denomination in aggregate principal amount equal to and in
exchange for the portion of the principal of the Security so surrendered that
was not repurchased.

        (g) Any Holder that has delivered to the Trustee a Change in Control
Purchase Notice shall have the right to withdraw such notice at any time prior
to the close of business on the Repurchase Date by delivery of a written notice
of withdrawal to the Paying Agent prior to the close of business on such date.
The notice of withdrawal shall state the principal amount and the certificate
numbers of the Securities as to which the withdrawal notice relates and the
principal amount, if any, which remains subject to the notice of exercise of a
repurchase right. A Security in respect of which a Holder has exercised its
option to require repurchase upon a Change in Control may thereafter be
converted into Common Stock only if such Holder withdraws its notice in
accordance with the preceding sentence.

        (h) Any issuance of shares of Common Stock in respect of the Repurchase
Price shall be deemed to have been effected immediately prior to the close of
business on the Repurchase Date and the person or persons in whose name or names
any certificate or certificates for shares of Common Stock shall be issuable
upon such repurchase shall be deemed to have become on the Repurchase Date the
holder or holders of record of the shares represented thereby; provided,
however, that any surrender for repurchase on a date when the stock transfer
books of the Company shall be closed shall constitute the person or persons in
whose name or names the certificate or certificates for such shares are to be
issued as the record holder or holders thereof for all purposes at the opening
of business on the next succeeding day on which such stock transfer books are
open. No payment or adjustment shall be made for dividends or distributions on
any Common Stock issued upon repurchase of any Security declared prior to the
Repurchase Date.

        (i) No fractional shares of Common Stock or scrip representing
fractional shares shall be issued upon repurchase of Securities. If more than
one Security shall be repurchased from the same holder and the Repurchase Price
shall be payable in shares of Common Stock, the number of full shares which
shall be issued upon repurchase shall be computed on the basis of the aggregate
principal amount of the Securities (or specified portions thereof to the extent
permitted hereby) so repurchased. If any fractional share of stock otherwise
would be issuable upon repurchase of any Security or Securities, the Company
shall make an adjustment therefor in cash at the current market value thereof to
the Holder of Securities. For these purposes, the current market value of a
share of Common Stock shall be the Closing Price on the first Trading Day
immediately preceding the Repurchase Date.

        (j) The issue of stock certificates on repurchase of Securities shall be
made without charge to the Holder of Securities being repurchased for any tax in
respect of the issue thereof. The Company shall not, however, be required to pay
any tax which may be payable in respect of any transfer involved in the issue
and delivery of stock in any name other than that of the Holder

                                      -48-

<PAGE>   55

of any Security repurchased, and the Company shall not be required to issue or
deliver any such stock certificate unless and until the person or persons
requesting the issue thereof shall have paid to the Company the amount of such
tax or shall have established to the satisfaction of the Company that such tax
has been paid.

        Section 12.04. Certain Definitions. For purposes of this Article 12:

        (a) the terms "BENEFICIAL OWNER" and "BENEFICIAL OWNERSHIP" shall be
determined in accordance with Rules 13d-3 and 13d-5 promulgated by the
Commission pursuant to the Securities Exchange Act of 1934, as amended (the
"EXCHANGE ACT"), except that a Person shall be deemed to have "BENEFICIAL
OWNERSHIP" of all securities that such Person has the right to acquire, whether
such right is exercisable immediately or only after the passage of time; and

        (b) the term "PERSON" shall include any syndicate or group which would
be deemed to be a "Person" under Section 13(d)(3) of the Exchange Act.

        Section 12.05. Change in Control. A "CHANGE IN CONTROL" shall be deemed
to have occurred at such time after the original issuance of the Securities as:

        (a) any "person " or "group" (as such terms are used in Sections 13(d)
and 14(d) of the Exchange Act), acquires the "beneficial ownership," directly or
indirectly, through a purchase, merger or other acquisition transaction, of more
than 50% of the Company's total outstanding voting stock other than an
acquisition by the Company, any of its Subsidiaries or any of its employee
benefit plans.

        (b) the Company shall consolidate with, or merge with or into another
Person or convey, transfer, lease or otherwise dispose 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 event pursuant to a transaction in which the
Company's outstanding voting stock is converted into or exchanged for cash,
securities or other property, other than any such transactions where:

        (i)  the Company's voting stock is not converted or exchanged at all
        (except to the extent necessary to reflect a change in the Company's
        jurisdiction of incorporation) or is converted into or exchanged for
        voting stock (other than Redeemable Capital Stock) of the surviving or
        transferee corporation, and

        (ii) immediately after such transaction, no "person" or "group" (as such
        terms are used in Sections 13(d) and 14(d) of the Exchange Act) is the
        "beneficial owner", directly or indirectly, of more than 50% of the
        total outstanding voting stock of the surviving or transferee
        corporation, unless such person or group was the beneficial owner,
        directly or indirectly, of more than 50% of the total outstanding voting
        stock of the Company on the date hereof;

        (c) during any consecutive two-year period, individuals who at the
beginning of such period constituted the Board of Directors (together with any
new directors whose election to such Board of Directors, or whose nomination for
election by the Company's stockholders, was approved by a vote of a majority of
the directors then still in office who were either directors at

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<PAGE>   56

the beginning of such period of whose election or nomination for election was
previously so approved) cease for any reason to constitute a majority of the
Board of Directors then in office;

        (d) a special resolution is passed by the Company's stockholders
approving a plan of liquidation or dissolution other than in a transaction which
complies with the provisions described in Article 8 of the Indenture.

        "REDEEMABLE CAPITAL STOCK" means any class of series of capital stock
that, either by its terms, by the terms of any security into which it is
convertible or exchangeable or by contract or otherwise, is, or upon the
happening of an event or passage of time would be, required to be redeemed prior
to the final stated maturity of the Securities or is redeemable at the option of
the holder thereof at any time prior to such final stated maturity, or is
convertible into or exchangeable for debt securities at any time prior to such
final stated maturity; provided, however, that Redeemable Capital Stock shall
not include any common stock the holder of which has the right to put to the
Company upon certain terminations of employment.

        Section 12.06. References to Repurchase Price. Whenever in this
Indenture there is a reference, in any context, to the principal of any Security
as of any time, such reference shall be deemed to include reference to the
Repurchase Price payable in respect of such Security to the extent that such
Repurchase Price is, was or would be so payable at such time, and express
mention of the Repurchase Price in any provision of this Indenture shall not be
construed as excluding the Repurchase Price in those provisions of this
Indenture when such express mention is not made; provided, however, that for the
purposes of this Article 12, such reference shall be deemed to include reference
to the Repurchase Price only if the Repurchase Price is payable in cash.

                                   ARTICLE 13
                                   CONVERSION

        Section 13.01. Conversion Privilege and Conversion Price. Subject to and
upon compliance with the provisions of this Article 13, at the option of the
Holder thereof, any Security or any portion of the principal amount thereof
which is $1,000 or an integral multiple of $1,000 may be converted at the
principal amount thereof, or of such portion thereof, into fully paid and
nonassessable shares of Common Stock of the Company (the "CONVERSION SHARES") at
any time following the date of original issuance of Securities at the conversion
price, determined as hereinafter provided, in effect at the time of conversion.
Such conversion right shall expire at the close of business on __________, 2005,
subject to any rules and procedures of the depositary for such security in
effect from time to time (the "APPLICABLE PROCEDURES"). In case a Security or
portion thereof has previously been called for redemption at the election of the
Company, such conversion right in respect of the Security or portion so called
shall expire at the close of business, New York City time, on the Redemption
Date, unless the Company defaults in making the payment due upon redemption (in
each case subject as aforesaid to any Applicable Procedures). A Security in
respect of which a Holder has delivered a Change in Control Purchase Notice (as
defined in Article 12 hereof) exercising the option of such Holder to require
the Company to purchase such Security may be converted only if such notice is
withdrawn by a

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<PAGE>   57

written notice of withdrawal delivered by the Holder to the Paying Agent prior
to the close of business on the Repurchase Date, in accordance with the terms of
this Indenture.

        The price at which shares of Common Stock shall be delivered upon
conversion (herein called the "CONVERSION PRICE") shall be initially $_____ per
share of Common Stock, which is equal to a conversion rate of _____ shares per
$1,000 principal amount of the Securities (the "CONVERSION RATE"). The
conversion price shall be adjusted in certain instances as provided in Section
13.04.

        In case the Company shall, by dividend or otherwise, declare or make a
distribution on its Common Stock referred to in Section 13.04(d) or 13.04(e)
(including dividends or distributions referred to in the last sentence of
Section 13.04(d)), the Holder of each Security, upon the conversion thereof
pursuant to this Article 13 subsequent to the close of business on the date
fixed for the determination of stockholders entitled to receive such
distribution and prior to the effectiveness of the conversion price adjustment
in respect of such distribution pursuant to Section 13.04(d) or 13.04(e), shall
also be entitled to receive for each share of Common Stock into which such
Security is converted, the portion of the evidences of indebtedness, shares of
capital stock, securities, cash and other property so distributed applicable to
one share of Common Stock; provided, however, that, at the election of the
Company (whose election shall be evidenced by a Board Resolution) with respect
to all Holders so converting, the Company may, in lieu of distributing to such
Holder any portion of such distribution not consisting of cash or securities of
the Company, pay such Holder an amount in cash equal to the fair market value
thereof (as determined in good faith by the Board of Directors, whose
determination shall be conclusive and described in a Board Resolution). If any
conversion of a Security described in the immediately preceding sentence occurs
prior to the payment date for a distribution to holders of Common Stock which
the Holder of the Security so converted is entitled to receive in accordance
with the immediately preceding sentence, the Company may elect (such election to
be evidenced by a Board Resolution) to distribute to such Holder a due bill for
the evidences of indebtedness, shares of capital stock, securities, cash or
assets to which such Holder is so entitled; provided that such due bill (i)
meets any applicable requirements of the principal national securities exchange
or other market on which the Common Stock is then traded and (ii) requires
payment or delivery of such evidences of indebtedness, shares of capital stock,
securities, cash or assets no later than the date of payment or delivery thereof
to holders of Common Stock receiving such distribution.

        Section 13.02. Exercise of Conversion Privilege. In order to exercise
the conversion privilege, the Holder of any Security to be converted shall
surrender such Security, duly endorsed or assigned to the Company or in blank,
at any office or agency maintained by the Company pursuant to Section 10.02 of
this Indenture, accompanied by (a) written notice to the Company in
substantially the form of conversion notice attached to the form of Security
attached as Exhibit A hereto at such office or agency that the Holder elects to
convert such Security or, if less than the entire principal amount thereof is to
be converted, the portion thereof to be converted and (b) if shares or any
portion of such Security not to be converted are to be issued in the name of a
Person other than the Holder thereof, the name of the Person in which to issue
such shares.

                                      -51-

<PAGE>   58

        Except as provided in Sections 5.02 and 13.02 of this Indenture, no
Holder of Security will be entitled upon conversion thereof to any payment or
adjustment on account of accrued and unpaid interest thereon or on account of
dividends on the shares of Common Stock issued in connection therewith.
Securities surrendered for conversion during the period from the close of
business on any Regular Record Date to the opening of business on the
corresponding Interest Payment Date (except Securities or a portion thereof
being converted that shall have been called for redemption on a Redemption Date
during the period from the close of business on any Regular Record Date to the
opening of business on the corresponding Interest Payment Date) must be
accompanied by payment to the Company in immediately available funds or other
funds acceptable to the Company of an amount equal to the interest payable on
such Interest Payment Date on the principal amount converted.

        Securities shall be deemed to have been converted immediately prior to
the close of business on the day of surrender of such Securities for conversion
in accordance with the foregoing provisions (the "CONVERSION DATE"), and at such
time the rights of the Holders of such Securities as Holders shall cease, and
the Person or Persons entitled to receive the Common Stock issuable upon
conversion shall be treated for all purposes as the record holder or holders of
such Common Stock at such time. As promptly as practicable on or after the
Conversion Date, but in any event no later than the seventh Business Day
following the Conversion Date, the Company shall issue and shall deliver at such
office or agency a certificate or certificates for the number of full shares of
Common Stock issuable upon conversion, together with payment in lieu of any
fraction of a share as provided in Section 13.03. In the event the Company fails
to issue and deliver such certificate or certificates for such number of full
shares of Common Stock, then interest shall accrue on the aggregate conversion
price of such number of full shares from and after the seventh Business Day
following the Conversion Date to but excluding the date such shares are issued
and delivered. Such interest shall be due and payable upon demand of the
applicable Holder.

        In the case of any Security which is converted in part only, upon such
conversion the Company shall execute and the Trustee shall authenticate and
deliver to the Holder thereof, at the expense of the Company, a new Security or
Securities of authorized denominations in aggregate principal amount equal to
the unconverted portion of the principal amount of such Security. Any
requirements for notice, surrender or delivery of Securities pursuant to this
Article 13 shall be subject to any Applicable Procedures.

        Section 13.03. Fraction of Shares. No fractional shares of Common Stock
shall be issued upon conversion of Securities. If more than one Security shall
be surrendered for conversion at one time by the same Holder, the number of full
shares which shall be issuable upon conversion thereof shall be computed on the
basis of the aggregate principal amount of the Securities (or specified portions
thereof) so surrendered. Instead of any fractional share of Common Stock which
would otherwise be issuable upon conversion of any Security (or specified
portions thereof), the Company shall pay a cash adjustment in respect of such
fraction in an amount equal to the same fraction of the Closing Price per share
of the Common Stock at the close of business on the Trading Day immediately
preceding the Conversion Date or, alternatively, the Company shall round up to
the next higher whole share.

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<PAGE>   59

        "TRADING DAY" shall mean each day on which the primary securities
exchange or quotation system which is used to determine the Closing Price is
open for trading or quotation.

        "CLOSING PRICE" of a single share of Common Stock on any Trading Day
shall mean the closing sale price per share for the Common Stock (or if no
closing sale price is reported, the average of the bid and ask prices or, if
more than one in either case, the average of the average bid prices and the
average ask prices) on such Trading Day as reported in composite transactions
for the principal United States securities exchange on which the Common Stock is
traded or, if the Common Stock is not listed on a United States national or
regional stock exchange, as reported by the National Association of Securities
Dealers Automated Quotation System.

        In the event the Company fails to make any fractional share payment as
set forth above, then interest shall accrue on the amount of such fractional
share payment from and after the seventh Business Day following the Conversion
Date to but excluding the date such fractional share payment is made. Such
interest shall be due and payable upon demand of the applicable Holder.

        Section 13.04. Adjustment of Conversion Price. (a) In case the Company
shall pay or make a dividend or other distribution on its Common Stock
exclusively in Common Stock, the conversion price in effect at the opening of
business on the day next following the date fixed for the determination of
stockholders entitled to receive such dividend or other distribution shall be
reduced by multiplying such conversion price by a fraction of which the
numerator shall be the number of shares of Common Stock outstanding at the close
of business on the date fixed for such determination and the denominator shall
be the sum of such number of shares and the total number of shares constituting
such dividend or other distribution, such reduction to become effective
immediately after the opening of business on the day next following the date
fixed for such determination. For the purposes of this Section 13.04(a), the
number of shares of Common Stock at any time outstanding shall not include
shares held in the treasury of the Company but shall include shares issuable in
respect of scrip certificates issued in lieu of fractions of shares of Common
Stock. The Company shall not pay any dividend or make any distribution on shares
of Common Stock held in the treasury of the Company.

        (b) In case the Company shall pay or make a dividend or other
distribution on its Common Stock consisting exclusively of, or shall otherwise
issue to all holders of its Common Stock, rights, warrants or options entitling
the holders thereof, for a period not exceeding 45 days, to subscribe for or
purchase shares of Common Stock at a price per share less than the current
market price per share (determined as provided in Section 13.04(g)) of the
Common Stock on the date fixed for the determination of stockholders entitled to
receive such rights, warrants or options, the conversion price in effect at the
opening of business on the day following the date fixed for such determination
shall be reduced by multiplying such conversion price by a fraction of which the
numerator shall be the number of shares of Common Stock outstanding at the close
of business on the date fixed for such determination plus the number of shares
of Common Stock which the aggregate of the offering price of the total number of
shares of Common Stock so offered for subscription or purchase would purchase at
such current market price and the denominator shall be the number of shares of
Common Stock outstanding at the close of business on the date fixed for such
determination plus the number of shares of Common Stock so offered for
subscription or purchase, such reduction to become effective immediately

                                      -53-

<PAGE>   60

after the opening of business on the day following the date fixed for such
determination. For the purposes of this Section 13.04(b), the number of shares
of Common Stock at any time outstanding shall not include shares held in the
treasury of the Company but shall include shares issuable in respect of scrip
certificates issued in lieu of fractions of shares of Common Stock. The Company
shall not issue any rights, warrants or options in respect of shares of Common
Stock held in the treasury of the Company.

        (c) In case outstanding shares of Common Stock shall be subdivided into
a greater number of shares of Common Stock, the conversion price in effect at
the opening of business on the day following the day upon which such subdivision
becomes effective shall be proportionately reduced, and, conversely, in case
outstanding shares of Common Stock shall each be combined into a smaller number
of shares of Common Stock, the conversion price in effect at the opening of
business on the day following the day upon which such combination becomes
effective shall be proportionately increased, such reduction or increase, as the
case may be, to become effective immediately after the opening of business on
the day following the day upon which such subdivision or combination becomes
effective.

        (d) Subject to the last sentence of this Section 13.04(d), in case the
Company shall, by dividend or otherwise, distribute to all holders of its Common
Stock evidences of its indebtedness, shares of any class of capital stock,
securities, cash or property (excluding any rights, warrants or options referred
to in Section 13.04(b), any dividend or distribution paid exclusively in cash
and any dividend or distribution referred to in Section 13.04(a)), the
conversion price shall be reduced so that the same shall equal the price
determined by multiplying the conversion price in effect immediately prior to
the effectiveness of the conversion price reduction contemplated by this Section
13.04(d) by a fraction of which the numerator shall be the current market price
per share (determined as provided in Section 13.04(g)) of the Common Stock on
the date of such effectiveness less the fair market value (as determined in good
faith by the Board of Directors, whose determination shall be conclusive and
described in a Board Resolution and shall, in the case of securities being
distributed for which prior thereto there is an actual or when issued trading
market, be no less than the value determined by reference to the average of the
Closing Prices in such market over the period specified in the succeeding
sentence), on the date of such effectiveness, of the portion of the evidences of
indebtedness, shares of capital stock, securities, cash and property so
distributed applicable to one share of Common Stock and the denominator shall be
such current market price per share of the Common Stock, such reduction to
become effective immediately prior to the opening of business on the day next
following the later of (i) the date fixed for the payment of such distribution
and (ii) the date 20 days after the notice relating to such distribution is
given pursuant to Section 13.06 (such later date of (i) and (ii) being referred
to as the "REFERENCE DATE"). The provisions of this Section 13.04(d) shall not
be applicable to an event covered by Section 13.04(j). If the Board of Directors
determines the fair market value of any distribution for purposes of this
Section 13.04(d) by reference to the actual or when issued trading market for
any securities comprising such distribution, it must in doing so consider the
prices in such market over the same period used in computing the current market
price per share pursuant to Section 13.04(g). For purposes of this Section
13.04(d), any dividend or distribution that includes shares of Common Stock or
rights, warrants or options to subscribe for or purchase shares of Common Stock
shall be deemed instead to be (A) a dividend or distribution of the evidences of
indebtedness, cash, property, shares of capital stock or securities other than
such shares of

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<PAGE>   61

Common Stock or such rights, warrants or options (making any conversion price
reduction required by this Section 13.04(d)) immediately followed by (B) a
dividend or distribution of such shares of Common Stock or such rights (making
any further conversion price reduction required by Sections 13.04(a) or
13.04(b)), except (1) the Reference Date of such dividend or distribution as
defined in this Section 13.04(d) shall be substituted as "the date fixed for the
determination of stockholders entitled to receive such dividend or other
distributions", "the date fixed for the determination of stockholders entitled
to receive such rights, warrants or options" and "the date fixed for such
determination" within the meaning of Sections 13.04(a) and 13.04(b) and (2) any
shares of Common Stock included in such dividend or distribution shall not be
deemed "outstanding at the close of business on the date fixed for such
determination" within the meaning of this Section 13.04(b).

        (e) In case the Company shall, by dividend or otherwise, make a
distribution to all holders of its Common Stock exclusively in cash in an
aggregate amount that, together with (i) the aggregate amount of any other
distributions to all holders of its Common Stock made exclusively in cash within
the 12 months preceding the date of payment of such distribution and in respect
of which no conversion price adjustment pursuant to this Section 13.04(e) has
been made and (ii) the aggregate of any cash plus the fair market value (as
determined in good faith by the Board of Directors, whose determination shall be
conclusive and described in a Board Resolution), as of the expiration of the
tender or exchange offer referred to below, of consideration payable in respect
of any tender or exchange offer by the Company or a Subsidiary for all or any
portion of the Common Stock concluded within the 12 months preceding the date of
payment of such distribution and in respect of which no conversion price
adjustment pursuant to this Section 13.04(f) has been made, exceeds 10% of the
product of the current market price per share (determined as provided in this
Section 13.04(g) of the Common Stock as of the Trading Day immediately preceding
the record date fixed for stockholders entitled to receive such distribution
times the number of shares of Common Stock outstanding on such record date, the
conversion price shall be reduced so that the same shall equal the price
determined by multiplying the conversion price in effect immediately prior to
the effectiveness of the conversion price reduction contemplated by this Section
13.04(e) by a fraction of which the numerator shall be the current market price
per share (determined as provided in this Section 13.04(e) of the Common Stock
on the date of such effectiveness less an amount equal to the quotient of (x)
the excess of such combined amount over such 10% and (y) the number of shares of
Common Stock outstanding on the record date and (iii) the denominator of which
shall be equal to the current market price on such record date, such reduction
to become effective immediately prior to the opening of business on the later of
(a) the day following the record date fixed for the payment of such distribution
and (b) the date 20 days after the notice relating to such distribution is given
pursuant to Section 13.06.

        (f) In case a successful tender or exchange offer, other than an odd lot
offer, made by the Company or any Subsidiary for all or any portion of the
Common Stock shall involve an aggregate consideration having a fair market value
(as determined in good faith by the Board of Directors, whose determination
shall be conclusive and described in a Board Resolution) at the last time (the
"EXPIRATION TIME") tenders or exchanges may be made pursuant to such tender or
exchange offer (as it may be amended) that, together with (i) the aggregate of
the cash plus the fair market value (as determined in good faith by the Board of
Directors, whose determination shall be conclusive and described in a Board
Resolution), as of the expiration of the other tender

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<PAGE>   62

or exchange offer referred to below, of consideration payable in respect of any
other tender or exchange offer by the Company or a Subsidiary for all or any
portion of the Common Stock concluded within the preceding 12 months and in
respect of which no conversion price adjustment pursuant to this Section
13.04(f) has been made and (ii) the aggregate amount of any distributions to all
holders of the Common Stock made exclusively in cash within the preceding 12
months and in respect of which no conversion price adjustment pursuant to
Section 13.04(e) has been made, exceeds 10% of the product of the current market
price per share (determined as provided in Section 13.04(g)) of the Common Stock
outstanding (including any tendered shares) on the Expiration Time, the
conversion price shall be reduced (but not increased) so that the same shall
equal the price determined by multiplying the conversion price in effect
immediately prior to the Expiration Time by a fraction of which the numerator
shall be (i) the product of the current market price per share (determined as
provided in Section 13.04(g)) of the Common Stock on the Trading Day next
succeeding the Expiration Time times the number of shares of Common Stock
outstanding (including any tendered or exchanged shares) at the Expiration Time
minus (ii) the fair market value (determined as aforesaid) of the aggregate
consideration payable to stockholders based on the acceptance (up to any maximum
specified in the terms of the tender or exchange offer) of all shares validly
tendered or exchanged and not withdrawn as of the Expiration Time (the shares
deemed so accepted, up to any such maximum, being referred to as the "PURCHASED
SHARES") and the denominator shall be the product of (i) such current market
price per share on the Trading Day next succeeding the Expiration Time times
(ii) such number of outstanding shares at the Expiration Time less the number of
Purchased Shares, such reduction to become effective immediately prior to the
opening of business on the day following the Expiration Time.

        (g) For the purpose of any computation under this Section 13.04(g) and
Sections 13.04(b),(d) and (e), the current market price per share of Common
Stock on any date in question shall be deemed to be the average of the daily
Closing Prices per share of Common Stock for the ten consecutive Trading Days
immediately prior to the date in question; provided, however, that (i) if the
"ex" date (as hereinafter defined) for any event (other than the issuance or
distribution requiring such computation) that requires an adjustment to the
conversion price pursuant to Section 13.04(a), (b), (c), (d), (e) or (f) ("OTHER
EVENT") occurs on or after the 20th Trading Day prior to the date in question
and prior to the "ex" date for the issuance or distribution requiring such
computation (the "CURRENT EVENT"), the Closing Price for each Trading Day prior
to the "ex" date for such Other Event shall be adjusted by multiplying such
Closing Price by the same fraction by which the conversion price is so required
to be adjusted as a result of such Other Event, (ii) if the "ex" date for any
Other Event occurs after the "ex " date for the Current Event and on or prior to
the date in question, the Closing Price for each Trading Day on and after the
"ex" date for such Other Event shall be adjusted by multiplying such Closing
Price by the reciprocal of the fraction by which the conversion price is so
required to be adjusted as a result of such Other Event, (iii) if the "ex" date
for any Other Event occurs on the "ex" date for the Current Event, one of those
events shall be deemed for purposes of clauses (i) and (ii) of this proviso to
have an "ex" date occurring prior to the "ex" date for the Other Event, and (iv)
if the "ex" date for the Current Event is on or prior to the date in question,
after taking into account any adjustment required pursuant to clause (ii) of
this proviso, the Closing Price for each Trading Day on or after such "ex" date
shall be adjusted by adding thereto the amount of any cash and the fair market
value on the date in question (as determined in good faith by the Board of
Directors in a manner consistent with any determination of such value for
purposes of Section

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<PAGE>   63

13.04(d) or (e), whose determination shall be conclusive and described in a
Board Resolution) of the portion of the rights, warrants, options, evidences of
indebtedness, shares of capital stock, securities, cash or property being
distributed applicable to one share of Common Stock. For the purpose of any
computation under this Section 13.04(f), the current market price per share of
Common Stock on any date in question shall be deemed to be the average of the
daily Closing Prices for the 5 consecutive Trading Days selected by the Company
commencing on or after the latest (the "COMMENCEMENT DATE") of (i) the date 20
Trading Days before the date in question, (ii) the date of commencement of the
tender or exchange offer requiring such computation and (iii) the date of the
last amendment, if any, of such tender or exchange offer involving a change in
the maximum number of shares for which tenders are sought or a change in the
consideration offered, and ending not later than the Trading Day next succeeding
the Expiration Time of such tender or exchange offer (or, if such Expiration
Time occurs before the close of trading on a Trading Day, not later than the
Trading Day during which the Expiration Time occurs); provided, however, that if
the "ex" date for any Other Event (other than the tender or exchange offer
requiring such computation) occurs on or after the Commencement Date and on or
prior to the Trading Day next succeeding the Expiration Time for the tender or
exchange offer requiring such computation, the Closing Price for each Trading
Day prior to the "ex" date for such Other Event shall be adjusted by multiplying
such Closing Price by the same fraction by which the conversion price is so
required to be adjusted as a result of such other event. For purposes of this
paragraph, the term "ex" date, (i) when used with respect to any issuance or
distribution, means the first date on which the Common Stock trades regular way
on the relevant exchange or in the relevant market from which the Closing Price
was obtained without the right to receive such issuance or distribution, (ii)
when used with respect to any subdivision or combination of shares of Common
Stock, means the first date on which the Common Stock trades regular way on such
exchange or in such market after the time at which such subdivision or
combination becomes effective, and (iii) when used with respect to any tender or
exchange offer means the first date on which the Common Stock trades regular way
on such exchange or in such market after the Expiration Time of such tender or
exchange offer.

        (h) The Company may make such reductions in the conversion price, in
addition to those required by paragraphs (a), (b), (c), (d), (e) and (f) of this
Section 13.04, as it considers to be advisable in order that any event treated
for Federal income tax purposes as a dividend of stock or stock rights shall not
be taxable to the recipients, or to diminish the amount of such tax payable.

        (i) No adjustment in the conversion price shall be required (A) if
Holders may participate in the transactions otherwise giving rise to an
adjustment in the conversion price on a basis and with notice that the Board of
Directors determines to be fair and appropriate, or (B) unless such adjustment
would require an increase or decrease of at least 1% in the conversion price;
provided, however, that any adjustments which by reason of this Section
13.04(i)(B) are not required to be made shall be carried forward and taken into
account in any subsequent adjustment.

        (j) In the event that the Company distributes assets, debt securities,
rights, warrants or options (other than those referred to in Section 13.04(b)
above) pro rata to holders of Common Stock, and the fair market value of the
portion of assets, debt securities, rights, warrants or options applicable to
one share of Common Stock distributed to holders of Common Stock

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<PAGE>   64

exceeds the Average Sale Price (as defined below) per share of Common Stock, or
such Average Sale Price exceeds such fair market value by less than $1.00, then
so long as any such assets, debt securities, rights, options or warrants have
not expired or been redeemed by the Company, the Company shall make proper
provision so that the Holder of any Security upon conversion, rather than being
entitled to an adjustment in the conversion price, will be entitled to receive
upon such conversion, in addition to the Conversion Shares, a number of assets,
debt securities, rights, warrants and options to be determined as follows: (i)
if such conversion occurs on or prior to the date for the distribution to the
holders of assets, debt securities, rights, warrants or options of separate
certificates evidencing such assets, debt securities, rights, warrants or
options (the "DISTRIBUTION DATE"), the same number of assets, debt securities,
rights, warrants or options to which a holder of a number of shares of Common
Stock equal to the number of Conversion Shares is entitled at the time of such
conversion in accordance with the terms and provisions of and applicable to the
assets, debt securities, rights, warrants or options being distributed, and (ii)
if such conversion occurs after such Distribution Date, the same number of
assets, debt securities, rights, warrants or options to which a holder of the
number of shares of Common Stock into which the principal amount of such
Security so converted was convertible immediately prior to such Distribution
Date would have been entitled on such Distribution Date in accordance with the
terms and provisions of and applicable to the assets, debt securities, rights,
warrants or options.

        "AVERAGE SALE PRICE" means the average of the Closing Prices of the
Common Stock for the shorter of (i) 30 consecutive Trading Days ending on the
last full Trading Day prior to the Time of Determination (as defined below) with
respect to the rights, options, warrants or distribution in respect of which the
Average Sale Price is being calculated, or (ii) the period (x) commencing on the
date next succeeding the first public announcement of (a) the issuance of
rights, options or warrants or (b) the distribution, in each case, in respect of
which the Average Sale Price is being calculated and (y) proceeding through the
last full Trading Day prior to the Time of Determination with respect to the
rights, options, warrants or distribution in respect of which the Average Sale
Price is being calculated, or (iii) the period, if any, (x) commencing on the
date next succeeding the Ex-Dividend Time (as defined below) with respect to the
next preceding (a) issuance of rights, warrants or options or (b) distribution,
in each case, for which an adjustment is required by the provisions of Section
13.04(b) or Section 13.04(j) and (y) proceeding through the last full Trading
Day prior to the Time of Determination with respect to the rights, options,
warrants, or distribution in respect of which the Average Sale Price is being
calculated. If the Ex-Dividend Time (or in the case of a subdivision,
combination or reclassification, the effective date with respect thereto) with
respect to a dividend, subdivision, combination or reclassification to which
Section 13.04(a) or (b) applies occurs during the period applicable for
calculating "Average Sale Price" pursuant to the definition in the preceding
sentence, "Average Sale Price" shall be calculated for such period in a manner
determined in good faith by the Board of Directors to reflect the impact of such
dividend, subdivision, combination or reclassification on the Closing Price of
the Common Stock during such period.

        "TIME OF DETERMINATION" means the time and date of the earlier of (i)
the determination of stockholders entitled to receive rights, warrants or
options or a distribution, in each case, to which this Section 13.04(j) applies
and (ii) the time ("Ex-Dividend Time") immediately prior to the commencement of
"ex-dividend" trading for such rights, options, warrants or distribution on

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<PAGE>   65

the New York Stock Exchange or such other national or regional exchange or
market on which the shares of Common Stock are listed or quoted.

        Section 13.05. Notice of Adjustments of Conversion Price. Whenever the
conversion price is adjusted as herein provided: the Company shall compute the
adjusted conversion price in accordance with Section 13.04 and shall prepare a
certificate signed by the Chief Financial Officer of the Company setting forth
the adjusted conversion price and showing in reasonable detail the facts upon
which such adjustment is based, and such certificate shall forthwith be filed
(with a copy to the Trustee) at each office or agency maintained for the purpose
of conversion of Securities pursuant to Section 10.02 of the Indenture; and the
Company shall prepare a notice of such adjustment of the conversion price
setting forth the adjusted conversion price and the date on which each
adjustment becomes effective and shall mail such notice of such adjustment of
the conversion price to the Holder of each Security at such Holder's last
address appearing on the Security Register provided for in Section 3.04 of this
Indenture, within twenty (20) days after execution thereof. Failure to deliver
such notice shall not affect the legality or validity of any such adjustment.

        Section 13.06.  Notice of Certain Corporate Action.  In case:

        (a) the Company shall declare a dividend (or any other distribution) on
its Common Stock that would require a conversion price adjustment pursuant to
Section 13.04(e); or

        (b) the Company shall authorize the granting to all holders of its
Common Stock of rights, warrants or options to subscribe for or purchase any
shares of capital stock of any class or of any other rights (excluding rights
distributed pursuant to any stockholder rights plan); or

        (c) of any reclassification of the Common Stock of the Company (other
than a subdivision or combination of its outstanding shares of Common Stock), or
of any consolidation or merger to which the Company is a party and for which
approval of any stockholders of the Company is required, or of the sale or
transfer of all or substantially all of the assets of the Company; or

        (d) of the voluntary or involuntary dissolution, liquidation or winding,
up of the Company; or

        (e) the Company or any Subsidiary of the Company shall commence a tender
or exchange offer for all or a portion of the Company's outstanding shares of
Common Stock (or shall amend any such tender or exchange offer);

then the Company shall cause to be filed at each office or agency maintained for
the purpose of conversion of Securities pursuant to Section 10.02 of the
Indenture, and shall cause to be mailed to all Holders at their last addresses
as they shall appear in the Security Register, at least 20 days (or 10 days in
any case specified in clause 13.06(a) or 13.06(b) above) prior to the applicable
record, effective or expiration date hereinafter specified, a notice stating (x)
the date on which a record is to be taken for the purpose of such dividend,
distribution or granting of rights, warrants or options, or, if a record is not
to be taken, the date as of which the holders of Common Stock of record to be
entitled to such dividend, distribution, rights, warrants or options are to be
determined, or (y) the date on which such reclassification, consolidation,
merger, sale, transfer,

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<PAGE>   66
dissolution, liquidation or winding up is expected to become effective, and the
date as of which it is expected that holders of Common Stock of record shall be
entitled to exchange their shares of Common Stock for securities, cash or other
property deliverable upon such reclassification, consolidation, merger, sale,
transfer, dissolution, liquidation or winding up, or (z) the date on which such
tender offer commenced, the date on which such tender offer is scheduled to
expire unless extended, the consideration offered and the other material terms
thereof (or the material terms of any amendment thereto).

        Section 13.07. Company's Obligation Regarding Common Stock. The Company
shall at all times reserve and keep available, free from preemptive rights, out
of its authorized but unissued Common Stock, solely for the purpose of effecting
the conversion of Securities, the whole number of shares of Common Stock then
issuable upon the conversion in full of all outstanding Securities.

        Before taking any action which would cause an adjustment reducing the
conversion price below the then par value, if any, of the shares of Common Stock
issuable upon conversion of the Securities, the Company will take all corporate
action which may, in the opinion of its counsel, be necessary in order that the
Company may validly and legally issue shares of such Common Stock at such
adjusted conversion price.

        The Company covenants that if any shares of Common Stock to be provided
for the purpose of conversion of Securities hereunder require registration with
or approval of any governmental authority under any federal or state law before
such shares may be validly issued upon conversion, the Company will in good
faith and as expeditiously as practicable endeavor to secure such registration
or approval, as the case may be.

        The Company further covenants that so long as the Common Stock shall be
listed or quoted on the New York Stock Exchange, the Nasdaq Stock Market
(National Market), or any other national securities exchange the Company will,
if permitted by the rules of such exchange, list and keep listed so long as the
Common Stock shall be so listed on such market or exchange, all Common Stock
issuable upon conversion of the Securities.

        Section 13.08. Taxes on Conversions. The Company will pay any and all
taxes that may be payable in respect of the issue or delivery of shares of
Common Stock on conversion of Securities pursuant hereto. The Company shall not,
however, be required to pay any tax which may be payable in respect of any
transfer involved in the issue and delivery of shares of Common Stock in a name
other than that of the Holder of the Security or Securities to be converted, and
no such issue or delivery shall be made unless and until the Person requesting
such issue has paid to the Company the amount of any such tax, or has
established to the satisfaction of the Company that such tax has been paid.

        Section 13.09. Covenant as to Common Stock. The Company covenants that
all shares of Common Stock which may be issued upon conversion of Securities
shall upon issue be newly issued (and not treasury shares) and be duly
authorized, validly issued, fully paid and nonassessable and, except as provided
in Section 13.08, the Company shall pay all taxes, liens and charges with
respect to the issue thereof.

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<PAGE>   67

        Section 13.10. Cancellation of Converted Securities. All Securities
delivered for conversion shall be delivered to the Trustee to be cancelled by or
at the direction of the Trustee, which shall dispose of the same as provided in
Section 3.08 of this Indenture.

        Section 13.11. Provisions in Case of Reclassification, Consolidation,
Merger or Sale of Assets. In the event that the Company shall be a party to any
transaction (including any (i) recapitalization or reclassification of the
Common Stock (other than a change in par value, or from par value to no par
value, or from no par value to par value, or as a result of a subdivision or
combination of the Common Stock), (ii) any consolidation of the Company with, or
merger of the Company into, any other person, any merger of another person into
the Company (other than a merger which does not result in a reclassification,
conversion, exchange or cancellation of outstanding shares of Common Stock of
the Company), (iii) any sale, transfer or lease of all or substantially all of
the assets of the Company or (iv) any compulsory share exchange) pursuant to
which the Common Stock is converted into the right to receive other securities,
cash or other property, then lawful provision shall be made as part of the terms
of such transaction whereby the Holder of each Security then Outstanding shall
have the right thereafter to convert such Security only into (subject to funds
being legally available for such purpose under applicable law at the time of
such conversion) the kind and amount of securities, cash and other property
receivable upon such transaction by a holder of the number of shares of Common
Stock into which such Security might have been converted immediately prior to
such transaction. The Company or the person formed by such consolidation or
resulting from such merger or which acquired such assets or which acquired the
Company's shares of Common Stock, as the case may be, shall execute and deliver
to the Trustee a supplemental indenture establishing such rights. Such
supplemental indenture shall provide for adjustments which, for events
subsequent to the effective date of such supplemental indenture, shall be as
nearly equivalent as may be practicable to the adjustments provided for in this
Article. The above provisions of this Section 13.11 shall similarly apply to
successive transactions of the foregoing type.

        Section 13.12. Company's Obligation. All calculations, adjustments,
conversions and other determinations under this Article 13 shall be the sole
responsibility and obligation of the Company. The Trustee (a) shall have no
obligation to review, challenge or contest any such calculation, adjustment,
conversion or other determination and (b) shall not be liable for any default or
error by the Company under this Article 13.

                                   ARTICLE 14
                                  SUBORDINATION

        Section 14.01 Securities Subordinate to Senior Indebtedness. The Company
covenants and agrees, and each Holder of Securities, by such Holder's acceptance
thereof, likewise covenants and agrees, that, to the extent and in the manner
hereinafter set forth in this Article 14, the indebtedness represented by the
Securities and the payment of the principal of (and premium, if any), and
interest on and all other amounts payable under each and all of the Securities
including, but not limited to, the Redemption Prices, the Make-Whole Payment and
the Repurchase Price payable with respect to the Securities in accordance with
Article 11 or Article 12, as the case may be, and all obligations of the Company
under the Indenture are hereby

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<PAGE>   68

expressly made subordinate and subject in right of payment to the prior payment
in full of all Senior Indebtedness.

        Section 14.02. Payment over of Proceeds upon Dissolution, Etc. In the
event of (a) any insolvency or bankruptcy case or proceeding, or any
receivership, liquidation, reorganization or other similar case or proceeding in
connection therewith, relative to the Company or to its creditors, as such, or
to its assets, or (b) any liquidation, dissolution or other winding-up of the
Company, whether voluntary or involuntary and whether or not involving
insolvency or bankruptcy, or (c) any assignment for the benefit of creditors or
any other marshaling of assets and liabilities of the Company, then and in any
such event the holders of Senior Indebtedness shall be entitled to receive
payment in full of all amounts due or to become due on or in respect of all
Senior Indebtedness, or provision shall be made for such payment in cash or cash
equivalents or otherwise in a manner satisfactory to the holders of Senior
Indebtedness, before the Holders of the Securities are entitled to receive any
payment on account of principal of (or premium, if any), or interest on or any
other amount payable under the Securities, including, but not limited to, the
Redemption Prices, the Make-Whole Payment and the Repurchase Price payable with
respect to the Securities in accordance with Article 11 or Article 12, as the
case may be, and to that end the holders of Senior Indebtedness shall be
entitled to receive, for application to the payment thereof, any payment or
distribution of any kind or character, whether in cash, property or securities,
which may be payable or deliverable in respect of the Securities in any such
case, proceeding, dissolution, liquidation or other winding-up or event.

        In the event that, notwithstanding the foregoing provisions of this
Section 14.02, the Trustee or the Holder of Securities shall have received any
payment or distribution of assets of the Company prohibited by the foregoing
paragraph of any kind or character, whether in cash, property or securities,
before all Senior Indebtedness is paid in full or payment thereof provided for,
and if, at or prior to the time of such payment or distribution, written notice
that such payment or distribution is prohibited by the foregoing paragraph shall
have been actually given to a Responsible Officer of the Trustee or, as the case
may be, such Holder, then and in such event such payment or distribution shall
be paid over or delivered forthwith to the trustee in bankruptcy, receiver,
liquidating trustee, custodian, assignee, agent or other Person making payment
or distribution of assets of the Company for application to the payment of all
Senior Indebtedness remaining unpaid, to the extent necessary to pay all Senior
Indebtedness in full, after giving effect to any concurrent payment or
distribution to or for the holders of Senior Indebtedness.

        For purposes of this Article 14 only, the words "CASH, PROPERTY OR
SECURITIES" shall not be deemed to include shares of capital stock of the
Company as reorganized or readjusted, or securities of the Company or any other
corporation provided for by a plan of reorganization or readjustment which in
either case are subordinated in right of payment to all Senior Indebtedness
which may at the time be outstanding to substantially the same extent as, or to
a greater extent than, the Securities are so subordinated as provided in this
Article 14. The consolidation of the Company with, or the merger of the Company
into, another Person or the liquidation or dissolution of the Company following
the conveyance or transfer of its properties and assets substantially as an
entirety to another Person upon the terms and conditions set forth in Article 8
shall not be deemed a dissolution, winding-up, liquidation, reorganization,
assignment for the benefit of creditors or marshaling of assets and liabilities
of the Company for the purposes of this

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<PAGE>   69

Section 14.02 if the Person formed by such consolidation or into which the
Company is merged or which acquires by conveyance or transfer such properties
and assets substantially as an entirety, as the case may be, shall, as a part of
such consolidation, merger, conveyance or transfer, comply with the conditions
set forth in Article 8.

        Section 14.03. No Payment When Senior Indebtedness in Default. (a) In
the event and during the continuation of any default in the payment of principal
of (or premium, if any) or interest on any Senior Indebtedness beyond any
applicable grace period with respect thereto (unless and until such payment
default shall have been cured or waived in writing by the holders of such Senior
Indebtedness), or (b) any default (other than a payment default) with respect to
Senior Indebtedness occurs and is continuing that permits the acceleration of
the maturity thereof and judicial proceedings shall be pending with respect to
any such default or the Company receives written notice of such default (a
"SENIOR INDEBTEDNESS DEFAULT NOTICE"), then no payment shall be made by the
Company on account of principal of (or premium, if any) or interest on the
Securities or on account of the redemption, purchase or other acquisition of
Securities (including pursuant to Articles 2, 11, 12 and 13). Notwithstanding
the foregoing, payments with respect to the Securities may resume and the
Company may acquire Securities for cash when (x) the default with respect to the
Senior Indebtedness is cured or waived or ceases to exist or (y) in the case of
a default described in (b) above, 179 or more days pass after the Senior
Indebtedness Default Notice is received by the Company; provided, that the terms
of this Indenture otherwise permit the payment or acquisition of the Securities
at that time. If the Company receives a Senior Indebtedness Default Notice, then
a similar notice received within nine months thereafter relating to the same
default on the same issue of Senior Indebtedness shall not be effective to
prevent the payment or acquisition of the Securities as described in the first
sentence of this Section 14.03(a). In addition, no payment may be made on the
Securities if any Securities are declared due and payable prior to their Stated
Maturity by reason of the occurrence of an Event of Default until the earlier of
(i) 120 days after the date of such acceleration or (ii) the payment in full of
all Senior Indebtedness, but only if such payment is then otherwise permitted
under the terms of this Indenture.

        In the event that, notwithstanding the foregoing, the Company shall make
any payment to the Trustee or the Holder of Securities prohibited by the
foregoing provisions of this Section 14.03, and if, at or prior to the time of
such payment, written notice that such payment is prohibited by the foregoing
paragraph shall have been actually given to a Responsible Officer of the Trustee
or, as the case may be, such Holder, then and in such event such payment shall
be paid over and delivered forthwith to the Company.

        The provisions of this Section 14.03 shall not apply to any payment with
respect to which Section 14.02 would be applicable.

        Section 14.04. Payment Permitted If No Default. Nothing contained in
this Article 14 or elsewhere herein or in any of the Securities shall prevent
(a) the Company, at any time except during the pendency of any case, proceeding,
dissolution, liquidation or other winding-up, assignment for the benefit of
creditors or other marshaling of assets and liabilities of the Company referred
to in Section 14.02 or except under the conditions described in Section 14.03,
from making payments at any time of principal of (and premium, if any), or
interest on, or any other amount under the Securities, including, but not
limited to, the Redemption Prices, the

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<PAGE>   70
Make-Whole Payment and the Repurchase Price payable with respect to the
Securities in accordance with Article 11 or Article 12, as the case may be, or
(b) the application by the Trustee of any money deposited with it hereunder to
the payment of or on account of the principal of (and premium, if any), or
interest on, or any other amount under the Securities including, but not
limited to, the Redemption Prices, the Make-Whole Payment and the Repurchase
Price payable with respect to the Securities in accordance with Article 11 or
Article 12, as the case may be, or the retention of such payment by the
Holders, if, two Business Days prior to such application by the Trustee, the
Trustee had not received written notice that such payment would be prohibited
by the provisions of this Article 14.

        Section 14.05. Subrogation to Rights of Holders of Senior Indebtedness.
Subject to the payment in full of all Senior Indebtedness, and until the
Securities are paid in full, the Holders of the Securities shall be subrogated
(equally and ratably with the holders of all indebtedness of the Company which
by its express terms is subordinated to indebtedness of the Company to
substantially the same extent as the Securities are subordinated and is entitled
to like rights of subrogation) to the rights of the holders of such Senior
Indebtedness to receive payments and distributions of cash, property and
securities applicable to the Senior Indebtedness to the extent that payments and
distributions otherwise payable to Holders of Securities have been applied to
the payment of Senior Indebtedness as provided by this Article 14. For purposes
of such subrogation, no payments or distributions to the holders of the Senior
Indebtedness of any cash, property or securities to which the Holders of the
Securities or the Trustee would be entitled, except for the provisions of this
Article 14, and no payments over pursuant to the provisions of this Article 14
to the holders of Senior Indebtedness by Holders of the Securities or the
Trustee, shall, as among the Company, its creditors other than holders of Senior
Indebtedness and the Holders of the Securities, be deemed to be a payment or
distribution by the Company to or on account of the Senior Indebtedness.

        Section 14.06. Provisions Solely to Define Relative Rights. The
provisions of this Article 14 are and are intended solely for the purpose of
defining the relative rights of the Holders of the Securities on the one hand
and the holders of Senior Indebtedness on the other hand. Nothing contained in
this Article 14 or elsewhere herein or in the Securities is intended to or
shall:

        (a) impair, as among the Company, its creditors other than holders of
Senior Indebtedness and the Holders of the Securities, the obligation of the
Company, which is absolute and unconditional (and which, subject to the rights
under this Article 14 of the holders of Senior Indebtedness, is intended to rank
equally with all other general obligations of the Company), to pay to the
Holders of the Securities the principal of (and premium, if any), and interest
on, and any other amount payable under the Securities including, but not limited
to, the Redemption Prices and the Repurchase Price payable with respect to the
Securities in accordance with Article 11 and Article 12, respectively, as and
when the same shall become due and payable in accordance with their terms;

        (b) affect the relative rights against the Company of the Holders of the
Securities and creditors of the Company other than the holders of Senior
Indebtedness; or

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<PAGE>   71

        (c) prevent the Trustee or the Holder of any Securities from exercising
all remedies otherwise permitted by applicable law upon default under this
Indenture, subject to the rights, if any, under this Article 14 of the holders
of Senior Indebtedness to receive cash, property and securities otherwise
payable or deliverable to the Trustee or such Holder.

        Section 14.07. Trustee to Effectuate Subordination. Each Holder of
Securities by its acceptance thereof authorizes and directs the Trustee on its
behalf to take such action as may be necessary or appropriate to effectuate the
subordination provided in this Article 14 and appoints the Trustee its
attorney-in-fact for any and all such purposes.

        Section 14.08. No Waiver of Subordination Provisions. No right of any
present or future holder of any Senior Indebtedness to enforce subordination as
herein provided shall at any time in any way be prejudiced or impaired by any
act or failure to act on the part of the Company or by any act or failure to
act, in good faith, by any such holder, or by any noncompliance by the Company
with the terms, provisions and covenants of this Indenture, regardless of any
knowledge thereof any such holder may have or be otherwise charged with.

        Without in any way limiting the generality of the foregoing paragraph,
the holders of Senior Indebtedness may, at any time and from time to time,
without the consent of or notice to the Trustee or the Holders of the
Securities, without incurring responsibility to the Holders of the Securities
and without impairing or releasing the subordination provided in this Article 14
or the obligations hereunder of the Holders of the Securities to the holders of
Senior Indebtedness, do any one or more of the following:

        (a) change the manner, place or terms of payment or extend the time of
payment of, or renew or alter, Senior Indebtedness, or otherwise amend or
supplement in any manner Senior Indebtedness or any instrument evidencing the
same or any agreement under which Senior Indebtedness is outstanding;

        (b) sell, exchange, release or otherwise deal with any property pledged,
mortgaged or otherwise securing Senior Indebtedness;

        (c) release any Person liable in any manner for the collection of Senior
Indebtedness;

        (d) exercise or refrain from exercising any rights against the Company
and any other Person;

        (e) apply any and all sums received from time to time to the Senior
Indebtedness.

        Section 14.09. Notice to Trustee. The Company shall give prompt written
notice to the Trustee if, to the Company's knowledge, any payment to or by the
Trustee in respect of the Securities is prohibited by this Article 14.
Notwithstanding the provisions of this Article 14 or any other provision of this
Indenture, the Trustee shall not be charged with knowledge that any payment to
or by the Trustee in respect of the Securities is prohibited by this Article 14,
unless and until a Responsible Officer of the Trustee shall have received
written notice thereof from the Company or a holder of Senior Indebtedness or
from any trustee therefor; and, prior to the receipt of any such written notice,
the Trustee, subject to the provisions of Section 1.04, shall be entitled in all
respects to assume that no facts exist that would prohibit any payment in
respect of

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<PAGE>   72

the Securities; provided, however, that if a Responsible Officer of the Trustee
shall not have received the notice provided for in this Section 14.09 at least
two Business Days prior to the date upon which by the terms hereof any money may
become payable for any purpose (including the payment of the principal of (and
premium, if any) or interest on any Security), then, anything herein contained
to the contrary notwithstanding, the Trustee shall have full power and authority
to receive such money and to apply the same to the purpose for which such money
was received and shall not be affected by any notice to the contrary which may
be received by it within two Business Days prior to such date.

        Subject to the provisions of Article 6, the Trustee shall be entitled to
rely on the delivery to it of a written notice by a Person representing itself
to be a holder of Senior Indebtedness (or a trustee therefor) to establish that
such notice has been given by a holder of Senior Indebtedness (or a trustee
therefor). In the event that the Trustee determines in good faith that further
evidence is required with respect to the right of any Person as a holder of
Senior Indebtedness to participate in any payment or distribution pursuant to
this Article 14, the Trustee may request such Person to furnish evidence to the
reasonable satisfaction of the Trustee as to the amount of Senior Indebtedness
held by such Person, the extent to which such Person is entitled to participate
in such payment or distribution and any other facts pertinent to the rights of
such Person under this Article 14, and if such evidence is not furnished, the
Trustee may defer any payment to such Person pending judicial determination as
to the right of such Person to receive such payment.

        Section 14.10. Reliance on Judicial Order or Certificate of Liquidating
Agent. Upon any payment or distribution of assets of the Company referred to in
this Article 14, the Trustee, subject to the provisions of Article 6, and the
Holders of the Securities shall be entitled to rely upon any order or decree
entered by any court of competent jurisdiction in which such insolvency,
bankruptcy, receivership, liquidation, reorganization, dissolution, winding up
or similar case or proceeding is pending, or a certificate of the trustee in
bankruptcy, receiver, liquidating trustee, custodian, assignee for the benefit
of creditors, agent or other Person making such payment or distribution,
delivered to the Trustee or to the Holders of Securities, for the purpose of
ascertaining the Persons entitled to participate in such payment or
distribution, the holders of the Senior Indebtedness and other indebtedness of
the Company, the amount thereof or payable thereon, the amount or amounts paid
or distributed thereon and all other facts pertinent thereto or to this Article
14.

        Section 14.11. Trustee No Fiduciary for Holders of Senior Indebtedness.
The Trustee shall not be deemed to owe any fiduciary duty to the holders of
Senior Indebtedness and shall not be liable to any such holders if it shall in
good faith mistakenly pay over or distribute to Holders of Securities or to the
Company or to any other Person cash, property or securities to which any holders
of Senior Indebtedness shall be entitled by virtue of this Article 14 or
otherwise.

        Section 14.12. Rights of Trustee as Holder of Senior Indebtedness;
Preservation of Trustee's Rights. The Trustee in its individual capacity shall
be entitled to all the rights set forth in this Article 14 with respect to any
Senior Indebtedness which may at any time be held by it, to the same extent as
any other holder of Senior Indebtedness, and nothing in this Indenture shall
deprive the Trustee of any of its rights as such holder.

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<PAGE>   73

        Nothing in this Article 14 shall apply to claims of, or payments to, the
Trustee under or pursuant to Section 6.07.

        Section 14.13. Article Applicable to Paying Agents. In case at any time
any Paying Agent other than the Trustee shall have been appointed by the Company
and be then acting hereunder, the term "TRUSTEE" as used in this Article 14
shall in such case (unless the context otherwise requires) be construed as
extending to and including such Paying Agent within its meaning as fully for all
intents and purposes as if such Paying Agent were named in this Article 14 in
addition to or in place of the Trustee; provided, however, that Section 14.12
shall not apply to the Company or any Affiliate of the Company if it or such
Affiliate acts as Paying Agent.

        Section 14.14. Certain Conversions Deemed Payment. For the purposes of
this Article 14 only, (1) the issuance and delivery of junior securities upon
conversion of Securities in accordance with Article 13 shall not be deemed to
constitute a payment or distribution on account of the principal of or premium
or interest on Securities or on account of the redemption, purchase or other
acquisition of Securities, and (2) the payment, issuance or delivery of cash,
property or securities (other than junior securities) upon conversion of a
Security shall be deemed to constitute payment on account of the principal of
such Security. For the purposes of this Section 14.14, the term "JUNIOR
SECURITIES" means (a) shares of any stock of any class of the Company and (b)
securities of the Company which are subordinated in right of payment to the
prior payment in full of all Senior Indebtedness which may be outstanding at the
time of issuance or delivery of such securities to substantially the same extent
as, or to a greater extent than, the Securities are so subordinated as provided
in this Article 14. Nothing contained in this Article 14 or elsewhere in this
Indenture or in the Securities is intended to or shall impair, as among the
Company, its creditors other than holders of Senior Indebtedness and the Holders
of the Securities, the right, which is absolute and unconditional, of the Holder
of any Security to convert such Security in accordance with Article 13.

                                      -67-

<PAGE>   74

        IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be
duly executed all as of the day and year first above written.

                                        AETHER SYSTEMS, INC.

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

                                        FIRST UNION NATIONAL BANK, as Trustee

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

                                      -68-

<PAGE>   75
                                                                       EXHIBIT A

        [Legend for Global Security only

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

        UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), NEW YORK, NEW
YORK, 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
IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC, AND
ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN
AUTHORIZED REPRESENTATIVE OF DTC, ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR
VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL BECAUSE THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.]

                                      -69-

<PAGE>   76

                              AETHER SYSTEMS, INC.

                 _____ % CONVERTIBLE SUBORDINATED NOTE DUE 2005

        Registered                                                         $

        No. R-                                                             CUSIP

        -

        AETHER SYSTEMS, INC., a corporation duly organized and existing under
the laws of the State of Delaware (herein called the "COMPANY", which term
includes any successor under the Indenture hereinafter referred to), for value
received, hereby promises to pay to [CEDE & CO.]1 [ ] or registered assigns, the
principal sum of $      at the office or agency of the Company in the Borough of
Manhattan, The City of New York, on __________ in such coin or currency of the
United States of America as at the time of payment shall be legal tender for the
payment of public and private debts, and to pay interest on said principal sum
semiannually on __________ and __________ of each year, commencing __________,
2000 (each an "INTEREST PAYMENT DATE"), at said office or agency, in like coin
or currency, at the rate of _____% per annum, until the principal hereof is paid
or made available for payment. 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 __________ or __________
(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.

        Payment of the principal of, premium, if any, and interest on this
Security will be made at the office or agency of the Company in the Borough of
Manhattan, 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 either by (i) mailing a check for such interest, payable to or
upon the written order of the Person entitled thereto pursuant to Section 3.07
of the Indenture (as

--------
     1  For Global Securities Only.

                                      -70-

<PAGE>   77

defined herein) or (ii) transfer to an account maintained by the payee located
inside the United States.

        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.

                                      -71-

<PAGE>   78

        IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed.

                                         AETHER SYSTEMS, INC.

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

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

                                         FIRST UNION NATIONAL BANK, as Trustee

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

        TRUSTEE'S CERTIFICATE OF AUTHENTICATION

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

                                         FIRST UNION NATIONAL BANK, as Trustee

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

                                      -72-

<PAGE>   79

                          [FORM OF REVERSE OF SECURITY]

                              AETHER SYSTEMS, INC.

                  _____% CONVERTIBLE SUBORDINATED NOTE DUE 2005

        This Security is one of a duly authorized issue of Securities of the
Company designated as its _____% Convertible Subordinated Notes due 2005 (herein
called the "SECURITIES"), limited in aggregate principal amount to $__________,
issued and to be issued under an Indenture, dated as of March __, 2000 (the
"INDENTURE"), between the Company and First Union National Bank, as Trustee for
the Holders of Securities issued under said Indenture (herein called the
"TRUSTEE", which term includes any successor trustee under the Indenture), to
which Indenture and all indentures supplemental thereto reference is hereby made
for a statement of the respective rights, limitations of rights, duties and
immunities thereunder of the Company, the Trustee, the holders of Senior
Indebtedness and the Holders of the Securities and of the terms upon which the
Securities are, and are to be, authenticated and delivered.

        Subject to and upon compliance with the provisions of the Indenture, the
Holder of this Security is entitled, at its option, at any time on or before
maturity of the Securities, or in case this Security or a portion hereof is
called for redemption, then in respect of this Security or such portion hereof
until and including, but (unless the Company defaults in making the payment due
upon redemption or repurchase) not after, the close of business on the
Redemption Date or Repurchase Date, as the case may be, to convert this Security
(or any portion of the principal amount hereof which is U.S. $1,000 or an
integral multiple thereof), at the principal amount hereof, or of such portion,
into fully paid and nonassessable shares of Common Stock of the Company at a
conversion price equal to $_____ aggregate principal amount of Securities for
each share of Common Stock, which is equal to a conversion rate of _____ shares
of common stock per $1,000 principal amount of the Securities (or at the current
adjusted conversion price if an adjustment has been made as provided in Article
13 of the Indenture) by surrender of this Security, duly endorsed or assigned to
the Company or in blank, to the Company at its office or agency in the Borough
of Manhattan, The City of New York, accompanied by the conversion notice hereon
executed by the Holder hereof evidencing such Holder's election to convert this
Security, or if less than the entire principal amount hereof is to be converted,
the portion hereof to be converted, and, in case such surrender shall be made
during the period from the close of business on any Regular Record Date to the
opening of business on the corresponding Interest Payment Date (unless this
Security or the portion hereof being converted has been called for redemption on
a Redemption Date within such period between and including such Regular Record
Date and such Interest Payment Date), also accompanied by payment in funds
acceptable to the Company of an amount equal to the interest payable on such
Interest Payment Date on the principal amount of this Security then being
converted. Subject to the aforesaid requirement for payment of interest and, in
the case of a conversion after the close of business on any Regular Record Date
and on or before the corresponding Interest Payment Date, to the right of the
Holder of this Security (or any Predecessor Security) of record at such Regular
Record Date to receive an installment of interest (even if the Security has been
called for redemption on a Redemption Date within such period), no payment or
adjustment is to be made on conversion for interest

                                      -73-

<PAGE>   80

accrued hereon or for dividends on the Common Stock issued on conversion. No
fractions of shares or scrip representing fractions of shares will be issued on
conversion, but instead of any fractional interest the Company shall pay a cash
adjustment or round up to the next higher whole share as provided in Article 13
of the Indenture. The conversion price is subject to adjustment as provided in
Article 13 of the Indenture. In addition, the Indenture provides that in case of
certain reclassifications, consolidations, mergers, sales or transfers of assets
or other transactions pursuant to which the Common Stock is converted into the
right to receive other securities, cash or other property, the Indenture shall
be amended, without the consent of any Holders of Securities, so that this
Security, if then outstanding, will be convertible thereafter, during the period
this Security shall be convertible as specified above, only into the kind and
amount of securities, cash and other property receivable upon the transaction by
a holder of the number of shares of Common Stock into which this Security might
have been converted immediately prior to such transaction (assuming such holder
of Common Stock failed to exercise any rights of election and received per share
the kind and amount received per share by a plurality of non-electing shares).

        The Company will furnish to any Holder, upon request and without charge,
copies of the certificate of incorporation and by-laws of the Company then in
effect. Any such request may be addressed to the Company.

        The Securities may be redeemed at the election of the Company, as a
whole or from time to time in part, at any time prior to __________, 2003 (a
"PROVISIONAL REDEMPTION"), at a Redemption Price equal to $1,000 per $1,000
principal amount of the Securities plus accrued and unpaid interest, if any, to
but excluding the date of redemption (the "PROVISIONAL REDEMPTION DATE") if the
Closing Price of the Common Stock has exceeded 150% of the conversion price (as
defined in Article 13 of the Indenture) then in effect for at least 20 Trading
Days in any consecutive 30-Trading Day period ending on the Trading Day prior to
the date of mailing of the provisional notice of redemption pursuant to Section
11.04 (the "NOTICE DATE" ).

        Upon any such Provisional Redemption, the Company shall make an
additional payment in cash (the "MAKE-WHOLE PAYMENT") to holders of the
Securities called for redemption, including those Securities converted into
Common Stock between the Notice Date and the Provisional Redemption Date, in an
amount equal to $_____ per $1,000 principal amount of the Securities, less the
amount of any interest actually paid on the Securities before the Notice Date.

        The Securities (other than those Securities that have been converted in
accordance with the terms of the Indenture) are subject to redemption at the
option of the Company upon not less than 30 days' or more than 60 days' notice
by mail, as a whole or from time to time in part, at any time on or after
__________, 2003. The Redemption Prices (expressed as percentages of the
principal amount) shall be as set forth below for Securities redeemed during the
following 12-month period:

--------------------------------------------------------------------------------
               Period                                     Redemption Price

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

 __________, 2003 through __________, 2004                       _____%

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

                                      -74-

<PAGE>   81

and thereafter at a Redemption Price equal to _____% of the principal amount,
together, in the case of any such redemption, with accrued interest to (but not
including) the Redemption Date (subject to the right of holders of record on the
Regular Record Date to receive interest on the related Interest Payment Date).
Any redemption of Securities must be in integral multiples of $1,000.

        If fewer than all of the Securities are to be redeemed, the Trustee will
select the Securities to be redeemed in principal amounts at maturity of $1,000
or integral multiples thereof by lot, pro rata or by another method the Trustee
considers fair and appropriate. If a portion of a Holder's Securities is
selected for partial redemption and that holder converts a portion of those
Securities prior to the redemption, the converted portion shall be deemed,
solely for purposes of determining the aggregate principal amount of the
Securities to be redeemed by the Company, to be of the portion selected for
redemption.

        In certain circumstances involving a Change in Control, each Holder
shall have the right to require the Company to repurchase all or part of its
Securities at a repurchase price equal to 100% of the principal amount thereof,
together with accrued and unpaid interest to the Repurchase Date (subject to the
right of holders of record on the Regular Record Date to receive interest on the
related Interest Payment Date). At the option of the Company, the Repurchase
Price may be paid in cash or, subject to the conditions provided in the
Indenture, by delivery of shares of Common Stock having a fair market value
equal to the Repurchase Price. For the purposes of this paragraph, the fair
market value of shares of Common Stock shall be determined by the Company and
shall be equal to 95% of the average of the Closing Prices of the Common Stock
for the five consecutive Trading Days ending on and including the Third Trading
Day immediately preceding the Repurchase Date.

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

        In the event of redemption, conversion or repurchase of this Security in
part only, a new Security or Securities for the unredeemed, unconverted or
unrepurchased portion hereof will be issued in the name of the Holder hereof
upon the cancellation hereof.

        The indebtedness evidenced by this Security is, to the extent provided
in the Indenture, subordinate and subject in right of payment to the prior
payment in full of all Senior Indebtedness, and this Security is issued subject
to the provisions of the Indenture with respect thereto. Each Holder of this
Security, by accepting the same, (a) agrees to and shall be bound by such
provisions, (b) authorizes and directs the Trustee on his behalf to take such
action as may be necessary or appropriate to effectuate the subordination so
provided and (c) appoints the Trustee his attorney-in-fact for any and all such
purposes.

        If an Event of Default shall occur and be continuing, the principal of
all the Securities may be declared due and payable in the manner and with the
effect provided in Article 5 of the Indenture.

        Subject to certain conditions set forth in the Indenture, the Company at
any time may terminate some or all of its obligations under the Securities and
the Indenture if the Company

                                      -75-

<PAGE>   82

deposits with the Trustee money or Government Obligations for the payment of
principal and interest on the Securities to redemption or maturity, as the case
may be.

        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 with the consent of the Holders of a
majority in aggregate principal amount of the Securities at the time
Outstanding. The Indenture also contains provisions permitting the Holders of a
majority in aggregate principal amount of the Securities at the time
Outstanding, 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.

        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, premium, if any, and
interest on this Security at the times, place and rate, and in the coin or
currency, herein prescribed or to convert this Security as provided in the
Indenture.

        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
Corporate Trust Office 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.

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

        The depositary with respect to the Securities shall be The Depository
Trust Company.

        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 payment of or on this Security is 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. In the event that any date on which interest is
payable on the Securities is not a Business Day, then payment of interest
payable on such date will be made on the next

                                      -76-

<PAGE>   83

succeeding day which is a Business Day (and without any interest or other
payment in respect of any such delay).

        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 WITHOUT REGARD TO CONFLICT OF
LAWS PRINCIPLES.

                                      -77-

<PAGE>   84

                            FORM OF CONVERSION NOTICE

                                CONVERSION NOTICE

        To: AETHER SYSTEMS, INC.

        The undersigned Holder of this Security hereby irrevocably exercises the
option to convert this Security, or the portion hereof (which is $1,000 or an
integral multiple thereof) below designated, at any time following the date of
original issuance thereof, into shares of Common Stock in accordance with the
terms of the Indenture referred to in this Security, and directs that the shares
issuable and deliverable upon conversion, together with any check in payment for
a fractional share and any Security representing any unconverted principal
amount hereof, be issued and delivered to the registered owner hereof unless a
different name has been provided below. If shares or any portion of this
Security not converted are to be issued in the name of a person other than the
undersigned, the undersigned will pay all transfer taxes payable with respect
thereto and is delivering herewith a certificate in proper form certifying that
the applicable restrictions on transfer have been complied with. Any amount
required to be paid by the undersigned on account of interest accompanies this
Security.

        The undersigned hereby agrees that, promptly after request of the
Company, he or it will furnish such proof in support of this certification as
the Company or the Security Registrar for the Common Stock may, from time to
time, request.

Dated:

                                         By:
                                            ------------------------------
                                                   Signature*

                                         By:
                                            ------------------------------
                                                Signature Guaranty

                                      -78-

<PAGE>   85

<TABLE>
<S>                                     <C>
If shares or Securities are to be         Principal amount to be converted (if less than
registered in the name of a Person        all):$______,000
other than the Holder, please print
such Person's name and address:*
</TABLE>

------------------------------              ------------------------------------
Name                                        Social Security or Taxpayer
                                            Identification Number

------------------------------
Street Address

------------------------------
City, State and Zip Code

* Signature(s) must be guaranteed by an eligible guarantor institution (banks,
stock brokers, savings and loan associations and credit unions with membership
in an approved signature guarantee medallion program) pursuant to Securities and
Exchange Commission Rule 17Ad-15 if shares of Common Stock are to be delivered,
or unconverted Securities are to be issued, other than to and in the name of the
registered owner.

                                      -79-<PAGE>   1
                                                                     Exhibit 4.3

                               AMENDMENT NO. 1 TO
                                RIGHTS AGREEMENT

     Amendment No. 1 to Rights Agreement, dated as of March 14, 2000 (this
"Amendment"), is made and entered into by Aviall, Inc., a Delaware corporation
(the Company"). Capitalized terms used but not defined herein shall have the
meanings ascribed to such terms in the Rights Agreement, dated as of December 7,
1993 (the "Rights Agreement"), by and between the Company and BankBoston, N.A.,
a national banking association (as successor to The First National Bank of
Boston) (the "Rights Agent").

                                    RECITALS

     WHEREAS, Section 27 of the Rights Agreement provides that the Company may
from time to time supplement or amend any provision of the Rights Agreement as
the Company may deem necessary or desirable.

     NOW, THEREFORE, in accordance with Section 27 of the Rights Agreement, the
Company hereby amends the Rights Agreement as follows:

          1. Section 1(a) of the Rights Agreement is hereby amended and restated
in its entirety as follows:

               "Acquiring Person" shall mean any Person (as such term is
          hereinafter defined) who or which, together with all Affiliates and
          Associates (as such terms are hereinafter defined) of such Person,
          shall be the Beneficial Owner (as such term is hereinafter defined) of
          15% or more of the Common Shares of the Company then outstanding, but
          shall not include the Company, any Subsidiary (as such term is
          hereinafter defined) of the Company, any employee benefit plan of the
          Company or any Subsidiary of the Company, or any entity holding Common
          Shares for or pursuant to the terms of any such plan. Notwithstanding
          the foregoing, no Person shall become an "Acquiring Person" as the
          result of an acquisition of Common Shares by the Company which, by
          reducing the number of shares outstanding, increases the proportionate
          number of shares beneficially owned by such Person to 15% or more of
          the Common Shares of the Company then outstanding; provided, however,
          that if a Person shall become the Beneficial Owner of 15% or more of
          the Common Shares of the Company then outstanding by reason of share
          purchases by the Company and shall, after such share purchases by the
          Company, become the Beneficial Owner of any additional Common Shares
          of the Company, then such Person shall be deemed to be an "Acquiring
          Person". Notwithstanding the

<PAGE>   2

          foregoing, if the Board of Directors of the Company determines in good
          faith that a Person who would otherwise be an "Acquiring Person", as
          defined pursuant to the foregoing provisions of this paragraph (a),
          has become such inadvertently, and such Person divests as promptly as
          practicable a sufficient number of Common Shares so that such Person
          would no longer be an Acquiring Person, as defined pursuant to the
          foregoing provisions of this paragraph (a), then such Person shall not
          be deemed to be an "Acquiring Person" for any purposes of this
          Agreement.

          2. The Rights Agreement is hereby amended in the following additional
respects:

          (a) Section 2 is hereby amended by adding the following after the word
     "desirable": ", upon ten (10) days' prior written notice to the Rights
     Agent. The Rights Agent shall have no duty to supervise, and shall in no
     event be liable for, the acts or omissions of any such co-Rights Agent."

          (b) Section 18 is hereby amended by adding the word "gross" between
     the words "without" and "negligence" in the second sentence of Section 18.

          (c) Section 20(c) is hereby amended by adding the word "gross" between
     the words "own" and "negligence."

          (d) Section 26 is hereby amended by inserting the following address as
     the notice address for the Rights Agent:

              "BankBoston, N.A.
              c/o EquiServe Limited Partnership
              150 Royall Street
              Canton, MA 02021
              Attention: Client Administration"

          3. This Amendment shall be effective as of the date first above
written, and all references to the Rights Agreement shall, from and after such
time, be deemed to be references to the Rights Agreement as amended hereby.

          4. The Rights Agreement shall not otherwise be supplemented or amended
by virtue of this Amendment, but shall remain in full force and effect.

          5. Exhibits B and C to the Rights Agreement shall be deemed amended in
a manner consistent with this Amendment.

          6. This Amendment shall be deemed to be a contract made under the
substantive laws of the State of New York and for all purposes shall be governed
by and

                                        2

<PAGE>   3

construed in accordance with the substantive laws of the State of New York
applicable to contracts to be made and performed within such State.

          7. This Amendment may be executed in any number of counterparts and
each of such counterparts shall for all purposes be deemed to be an original,
and all such counterparts shall together constitute but one and the same
instrument.

     IN WITNESS WHEREOF, the Company and the Rights Agent have caused this
Amendment to be duly executed as of the date first above written.

                                AVIALL, INC.

                                By: /s/  JEFFREY J. MURPHY
                                   ----------------------------------------
                                Name: Jeffrey J. Murphy
                                Title: Senior Vice President and General Counsel

AGREED AND ACCEPTED:

BANKBOSTON, N.A.

By: /s/ JOSHUA P. MCGINN
    -----------------------------
    Name: Joshua P. Mcginn
    Title: Senior Account Manager

                                        3

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