Document:

<PAGE>   1
                                                                     EXHIBIT 4.1

                            CERTIFICATE OF AMENDMENT
                                       OF
                AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

         Intelect Communications, Inc., a corporation organized and existing
under and by virtue of the General Corporation Law of the State of Delaware,
DOES HEREBY CERTIFY:

         FIRST: That the Amended and Restated Certificate of Incorporation, as
amended, of said Corporation has been amended by amending Section 4.1 of Article
IV to read as follows:

SECTION 4.1. TOTAL NUMBER OF SHARES OF CAPITAL STOCK. The total number of shares
of capital stock of all classes which the Company shall have authority to issue
is 250,000,000 shares, consisting of 200,000,000 shares of Common Stock, par
value $0.01 per share (the "Common Stock"), and 50,000,000 shares of Preferred
Stock, par value $0.01 per share (the "Preferred Stock").

         SECOND, the aforesaid amendment was duly proposed by the Board of
Directors of the Corporation and was duly adopted by the stockholders of the
Corporation entitled to vote thereon in accordance with the applicable
provisions of section 242 of the General Corporation Law of the State of
Delaware.

         IN WITNESS WHEREOF, said Intelect Communications, Inc. has caused this
Certificate of Amendment to be signed by Herman M. Frietsch, its Chairman and
Chief Executive Officer and attested by Robert P. Capps, its Secretary, this
16th day of June, 2000.

                                   INTELECT COMMUNICATIONS, INC.

                                   By: /s/ Herman M. Frietsch
                                      ---------------------------------------
                                      Herman M. Frietsch
                                      Chairman and Chief Executive Officer

ATTEST:

By: /s/ Robert P. Capps
    ------------------------------------
        Robert P. Capps
        Secretary

<PAGE>   2

                            CERTIFICATE OF AMENDMENT
                                       OF
                AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

         Intelect Communications, Inc., a corporation organized and existing
under and by virtue of the General Corporation Law of the States of Delaware,
DOES HEREBY CERTIFY:

         FIRST: That the Amended and Restated Certificate of Incorporation of
said Corporation has been amended by inserting Section 4.1 of Article IV to read
as follows:

         Section 4.1. Total number of shares of Capital Stock. The total number
of shares of capital stock of all classes which the Company shall have authority
to issue is 150,000,000 shares, consisting of 100,000,000 shares of Common
Stock, par value $0.01 per share (the "Common Stock"), and 50,000,000 shares of
Preferred Stock, par value $0.01 per share (the "Preferred Stock").

         SECOND, the aforesaid amendment was duly proposed by the Board of
Directors of the Corporation and was duly adopted by the stockholders of the
Corporation entitled to vote thereon in accordance with the applicable
provisions of section 242 of the General Corporation Law of the State of
Delaware.

         IN WITNESS WHEREOF, said Intelect Communications, Inc. has caused this
certificate of be signed by Herman M. Frietsch, it Chairman and Chief Executive
Officer and attested by Edwin J. Ducayet, its Assistant Secretary, this 3rd day
of March, 1999.

                                INTELECT COMMUNICATIONS, INC.

                                By: /s/ Herman M. Frietsch
                                   --------------------------------------
                                   Herman M. Frietsch
                                   Chairman and Chief Executive Officer

ATTEST:

By: /s/ Edwin J. Ducayet, Jr.
   -----------------------------------
   Edwin J. Ducayet, Jr.
   Assistant Secretary

<PAGE>   3

                              AMENDED AND RESTATED
                          CERTIFICATE OF INCORPORATION
                                       OF
                          INTELECT COMMUNICATIONS, INC.

         This document constitutes an amendment and restatement of the original
Certificate of Incorporation of Intelect Communications, Inc. (the
"Corporation"), which was filed with the Secretary of State of Delaware on May
23, 1995. The name under which the original Certificate of Incorporation was
filed was Intelect Systems Corp. This Amended and Restated Certificate of
Incorporation was duly adopted in accordance with the provisions of Section
245(c) and 242 of the Delaware General Corporation Law.

                                    ARTICLE I

                                      Name

          The name of the Corporation is Intelect Communications, Inc.

                                   ARTICLE II

                          Address of Registered Office:
                            Name of Registered Agent

         The address of the registered office of the Corporation in the State of
Delaware is Corporation Trust Center, 1209 Orange Street, in the City of
Wilmington, county of New Castle, 19801. The name of its registered agent at
that address in the State of Delaware is The Corporation Trust Company.

                                   ARTICLE III

                               Purpose and Powers

         The purpose of the Corporation is to engage in any lawful act or
activity for which a Corporation may now or hereafter be organized under the
Delaware General Corporation Law ("Delaware Law"). It shall have all powers that
may now or hereafter be lawful for a corporation under the Delaware Law.

                                   ARTICLE IV

                                  Capital Stock

         Section 4.1. Total Number of Shares of Stock. The total number of
shares of capital stock of all classes that the Corporation shall have authority
to issue is 100,000,000 (One Hundred Million) shares. The authorized capital
stock is divided into 50,000,000 (Fifty Million) shares of preferred stock, of
the par value of $.01 each (the "Preferred Stock"), and 50,000,000 (Fifty
Million) shares of common stock, or the par value of $.01 each (the "Common
Stock").

                                       14
<PAGE>   4

         Section 4.2. Preferred Stock. (a) The shares of Preferred Stock of the
Corporation may be issued from time to time in one or more classes or series
thereof, the shares of each class or series thereof to have such voting powers,
full or limited, or no voting powers, and such designations, preferences and
relative, participating, optional or other special rights, and qualifications,
limitations or restrictions thereof, as are stated and expressed herein or in
the resolution or resolutions providing for the issue of such class or series,
adopted by the board of directors of the Corporation (the "Board of Directors")
as hereinafter provided.

         (b) Authority is hereby expressly granted to the Board of Directors,
subject to the provisions of this Article IV and to the limitations prescribed
by the Delaware Law, to authorize the issue of one or more classes, or series
thereof, of Preferred Stock and with respect to each such class or series to fix
by resolution or resolutions providing for the issue of such class or series the
voting powers, full or limited, if any, of the shares of such class or series
and the designations, preferences, and relative, participating, optional or
other special rights, and qualifications, limitations or restrictions thereof.
The authority of the Board of Directors with respect to each class or series
thereof shall include, but not be limited to the determination or fixing of the
following:

                  (i) the maximum number of shares to constitute such class or
         series, which may subsequently be increased or decreased by resolutions
         of the Board of Directors unless otherwise provided in the resolution
         providing for the issue of such class or series, the distinctive
         designation thereof and the sated value thereof if different than the
         par value thereof;

                  (ii) the dividend rate of such class or series, the conditions
         and dates upon which such dividends shall be payable, the relation
         which such dividends shall bear to the dividends payable on any other
         class or classes of stock or any other series of any class of stock of
         the Corporation, and whether such dividends shall be cumulative or
         noncumulative;

                  (iii) whether the shares of such class or series shall be
         subject to redemption, in whole or in part, and if made subject to such
         redemption the times, prices and other terms and conditions of such
         redemption, including whether or not such redemption may occur at the
         option of the Corporation or at the option of the holder or holders
         thereof or upon the happening of a special event;

                  (iv) the terms and amount of any sinking fund established for
         the purchase or redemption of the shares of such class or series;

                   (v) whether or not the shares of such class or series shall
         be convertible into or exchangeable for shares of any other class or
         classes of any stock or any other series of any class of stock of the
         Corporation, and, if provision is made for conversion or

<PAGE>   5

         exchange, the times, prices, rates, adjustments, and other terms and
         conditions of such conversion or exchange;

                  (vi) the extent, if any, to which the holders of shares of
         such class or series shall be entitled to vote with respect to the
         election of directors or otherwise;

                  (vii) the restrictions, if any, on the issue or reissue of any
         additional Preferred Stock;

                  (viii) the rights of the holders of the shares of such class
         or series upon the dissolution of, or upon the subsequent distribution
         or assets of, the Corporation; and

                  (ix) the manner in which any facts ascertainable outside the
         resolution or resolutions providing for the issue of such class or
         series shall operate upon the voting powers, designations, preferences,
         rights and qualifications, limitations or restrictions of such class or
         series.

         Section 4.3. Common Stock. The shares of Common Stock of the
Corporation shall be of one and the same class. The holders of Common Stock
shall have one vote per share of Common Stock on all matters on which holders of
Common Stock are entitled to vote.

                                    ARTICLE V

                               Board of Directors

         Section 5.1 Power of the Board of Directors. The business and affairs
of the Corporation shall be managed by or under the direction of its Board of
Directors which shall consist of not less than three members. In furtherance,
and not in limitation, of the powers conferred by the laws of the State of
Delaware, the Board of Directors is expressly authorized to:

         (a) adopt, amend, alter, change, or repeal the By-Laws of the
Corporation; provided, however, that no By-Laws hereafter adopted shall
invalidate any prior act of the directors that would have been valid if such new
By-Laws had not been adopted;

         (b) determine the rights, powers, duties, rules and procedures that
affect the power of the Board of Directors to manage and direct the business and
affairs of the Corporation, including the power to designate and empower
committees of the Board of Directors, to elect, appoint and empower the officers
and other agents of the Corporation, and to determine the time and place of the
notice requirements for Board meetings, as well as quorum and voting
requirements for and the manner of taking Board action; and

         (c) exercise all such powers and do all such acts as may be exercised
or done by the Corporation, subject to the provisions of the Delaware Law, this
Certificate of Incorporation and the By-Laws of the Corporation.

         Section 5.2. Number of Directors. The number of directors constituting
the Board of Directors shall be determined from time to time exclusively by a
vote of a majority of the Board of Directors in office at the time of such vote.

                                       17
<PAGE>   6

         Section 5.3. Classified Board of Directors. The directors shall be
divided into three classes, with each class to be as nearly equal in number as
reasonable possible, and with the initial term of office of the first class of
directors to expire at the 1998 annual meeting of stockholders, the initial term
of office of the second class of directors to expire at the 1999 annual meeting
of stockholders and the initial term of office of the third class of directors
to expire at the 2000 annual meeting of stockholders, in each case upon the
election and qualification of their successors. Commencing with the 1998 annual
meeting of stockholders, directors elected to succeed those directors whose
terms have thereupon expired shall be elected to a terms of office to expire at
the third succeeding annual meeting of stockholders after their election, and
upon the election and qualification of their successors. If the number of
directors is changed, any increase or decrease shall be apportioned among the
classes so as to maintain or attain the number of directors in each class as
nearly equal as reasonable possible, but in no case will a decrease in the
number of directors shorten the term of any incumbent director.

         Section 5.4 Vacancies. Any vacancies in the Board of Directors for any
reason and any newly created directorship resulting by reason of any increase in
the number of directors may be filled only by the Board of Directors, acting by
a majority of the remaining directors then in office, although less than a
quorum, or by a sole remaining director, and any directors so appointed shall
hold office until the next election of the class for which such directors have
been chosen and until their successors are elected and qualified.

         Section 5.5 Removal of Directors. Except as may be provided in a
resolution or resolutions providing for any class or series of Preferred Stock
pursuant to Article IV hereof with respect to any directors elected by the
holders of such class or series, any director may be removed from office at any
time, but only for cause, and only by the affirmative vote of the holders of at
least ninety percent (90%) of the voting power of all of the shares of capital
stock of the Corporation then entitled to vote generally in the election of
directors, voting together as a single class.

                                   ARTICLE VI

                 Stockholder Actions and Meeting of Stockholders

         Except as may be provided in a resolution or resolutions providing for
any class or series of Preferred Stock pursuant to Article IV hereof, any action
required or permitted to be taken by the stockholders of the Corporation must be
effected at a duly called annual or special meeting of such holders and may not
be effected by any written consent in lieu of a meeting by such holders. Special
meetings of stockholders of the Corporation may be called only by the Board of
Directors pursuant to a resolution adopted by a majority of the members of the
Board of Directors then in office. Election of directors need not be by written
ballot unless otherwise provided in the By-Laws.

<PAGE>   7

                                   ARTICLE VII

                      Limitation on Liability of Directors

         No person shall personally liable to the Corporation or its
stockholders for monetary damages for breach of a fiduciary duty as a director,
including , without limitation, directors serving on committees of the Board of
Directors; provided however, that the foregoing shall not eliminate or limit the
liability of a director (i) for any breach of the director's duty of loyalty to
the Corporation or its stockholders, (ii) for acts or omissions not in good
faith or which involve intentional misconduct or a knowing violation of law,
(iii) under Section 174 of the Delaware Law, or (iv) for any transaction from
which the director derived an improper personal benefit. If the Delaware Law is
amended hereafter to authorize corporate action further eliminating or limiting
the personal liability of directors, then the liability of a director of the
Corporation shall be eliminated or limited to the fullest extent permitted by
the Delaware Law as so amended. Any amendment, repeal or modification of this
Article VII shall not adversely affect any right or protection of a director of
the Corporation existing hereunder with respect to any act or omission occurring
prior to such amendment, repeal or modification.

                                  ARTICLE VIII

                              Amendment of By-Laws

         The power to adopt, amend, alter, change, or repeal any By-Laws of the
Corporation shall be vested exclusively with the Board of Directors.

                                   ARTICLE IX

                    Amendment of Certificate of Incorporation

         The Corporation hereby reserves the right to amend, alter, change or
repeal any provision contained in this Certificate of Incorporation in any
manner permitted by Delaware law and all rights and powers conferred upon
stockholders, directors, and officers herein are granted subject to this
reservation. Except as may be provided in a resolution or resolutions providing
for any class or series of Preferred Stock pursuant to Article IV hereof and
which relate to such class or series of Preferred Stock, any such amendment,
alteration, change or repeal shall require the affirmative vote of both (a) a
majority of the members of the Board of Directors then in office and (b) a
majority of the voting power of all of the shares of capital stock of the
Corporation entitled to vote generally in the election of directors voting
together as a single class; except that any proposal to amend, alter, change or
repeal the provisions of Article V, Article VI, Article VII, Article VIII, and
this Article IX shall require the affirmative vote of ninety percent (90%) of
the voting power of all of the shares of capital stock entitled to vote
generally in the election of directors, voting together as a single class.

<PAGE>   8

                                    ARTICLE X

                                  Severability

         In the event that any of the provisions of this Certificate of
Incorporation (including any provision within a single Section, paragraph or
sentence) are held by a court of competent jurisdiction to be unenforceable for
any reason, the remaining provisions of this Certificate of Incorporation shall
be and remain enforceable to the fullest extent permitted by law.

         THE UNDERSIGNED, being the Chairman and Chief Executive Officer of the
Corporation, for the purpose of amending and restating the Certificate of
Incorporation of the Corporation pursuant to Delaware Law does make this
Certificate, hereby declaring and certifying that this is the act and deed of
the Corporation and that the facts herein stated are true, and accordingly have
hereunto set my hand as of 28th day of October 1997.

                                   /s/ Herman M. Frietsch
                                  -----------------------------------------
                                  HERMAN M. FRIETSCH
                                  CHAIRMAN AND CHIEF EXECUTIVE OFFICER

                                  ATTEST:

                                  /s/ Edwin J. Ducayet, Jr.
                                  -----------------------------------------
                                  EDWIN J. DUCAYET, JR.
                                  ASSISTANT SECRETARY<PAGE>   1
                                                         EXHIBIT 4.1 "TIE SHEET"

                     ALLIED RISER COMMUNICATIONS CORPORATION

               RECONCILIATION AND TIE BETWEEN TRUST INDENTURE ACT
                OF 1939 AND INDENTURE, DATED AS OF JUNE 28, 2000

<TABLE>
<CAPTION>
Trust Indenture                                                                          Indenture
  Act Section                                                                             Section
-----------------                                                                        ---------
<S>                                                                                         <C>
Section 310(a)(1)..............................................................................6.8
           (a)(2)..............................................................................6.8
           (a)(3)...................................................................Not Applicable
           (a)(4)...................................................................Not Applicable
           (a)(5)..............................................................................6.8
           (b)................................................................................6.13
Section 311(a)................................................................................6.14
           (b)................................................................................6.14
           (c)................................................................................6.14
Section 312(a)................................................................................15.1
           (b)................................................................................15.2
           (c)................................................................................15.2
Section 313(a)................................................................................15.3
           (b)................................................................................15.3
           (c)................................................................................15.3
           (d)................................................................................15.3
Section 314(a)(1)-(3).........................................................................15.4
           (a)(4).............................................................................10.7
           (b)......................................................................Not Applicable
           (c)(1).........................................................................1.2, 4.1
           (c)(2).........................................................................1.2, 4.1
           (c)(3)...................................................................Not Applicable
           (d)......................................................................Not Applicable
           (e).................................................................................1.2
Section 315(a).................................................................................6.1
           (b)...........................................................................6.2, 1.13
           (c).................................................................................6.1
           (d).................................................................................6.1
           (e)................................................................................5.14
Section 316(a)(1)(A)..........................................................................5.12
           (a)(1)(B)..........................................................................5.13
           (a)(2)...................................................................Not Applicable
           (b)............................................................................5.7, 5.8
           (c)..............................................................................1.4(5)
Section 317(a)(1)..............................................................................5.3
           (a)(2)..............................................................................5.4
           (b)..........................................................................4.2, 13.14
Section 318(a)................................................................................1.13
</TABLE>

         Note: This reconciliation and tie shall not, for any purpose, be deemed
to be a part of the Indenture.

<PAGE>   2
                                                                     EXHIBIT 4.1

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

                    ALLIED RISER COMMUNICATIONS CORPORATION,

                                     ISSUER

                                       TO

                            WILMINGTON TRUST COMPANY,

                                     TRUSTEE

                                   ----------

                                    INDENTURE

                            Dated as of June 28, 2000

                                   ----------

                  7.50% CONVERTIBLE SUBORDINATED NOTES DUE 2007

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

<PAGE>   3

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                  Page
<S>             <C>                                                               <C>
              ARTICLE I DEFINITIONS AND OTHER PROVISIONS OF GENERAL
                                   APPLICATION

Section 1.1     Definitions..........................................................1
Section 1.2     Compliance Certificates and Opinions................................10
Section 1.3     Form of Documents Delivered to the Trustee..........................10
Section 1.4     Acts of Holders of Securities.......................................11
Section 1.5     Notices, Etc. to the Trustee and Company............................13
Section 1.6     Notice to Holders of Securities; Waiver.............................13
Section 1.7     Effect of Headings and Table of Contents............................14
Section 1.8     Successors and Assigns..............................................14
Section 1.9     Separability Clause.................................................14
Section 1.10    Benefits of Indenture...............................................14
Section 1.11    Governing Law.......................................................14
Section 1.12    Legal Holidays......................................................14
Section 1.13    Conflict With Trust Indenture Act...................................14

                            ARTICLE II SECURITY FORMS

Section 2.1     Form Generally......................................................15
Section 2.2     Form of Security....................................................16
Section 2.3     Form of Certificate of Authentication...............................29
Section 2.4     Form of Conversion Notice...........................................30
Section 2.5     Form of Assignment..................................................31

                           ARTICLE III THE SECURITIES

Section 3.1     Title and Terms.....................................................32
Section 3.2     Denominations.......................................................32
Section 3.3     Execution, Authentication, Delivery and Dating......................33
Section 3.4     Restrictive Legends.................................................33
Section 3.5     Registration; Registration of Transfer and Exchange;
                Restrictions on Transfer............................................36
Section 3.6     Book-Entry Provisions for Global Securities.........................37
Section 3.7     Special Transfer Provisions.........................................38
Section 3.8     Mutilated, Destroyed, Lost or Stolen Securities.....................41
Section 3.9     Payment of Interest; Interest Rights Preserved......................42
Section 3.10    Persons Deemed Owners...............................................43
Section 3.11    Cancellation........................................................43
Section 3.12    Computation of Interest.............................................43
Section 3.13    CUSIP Numbers.......................................................43
</TABLE>

                                       i
<PAGE>   4

<TABLE>
<S>             <C>                                                               <C>
                      ARTICLE IV SATISFACTION AND DISCHARGE

Section 4.1     Satisfaction And Discharge of Indenture.............................44
Section 4.2     Application of Trust Money..........................................45

                               ARTICLE V REMEDIES

Section 5.1     Events of Default...................................................45
Section 5.2     Acceleration of Maturity; Rescission and Annulment..................47
Section 5.3     Collection of Indebtedness and Suits for Enforcement by
                Trustee.............................................................48
Section 5.4     Trustee May File Proofs of Claim....................................48
Section 5.5     Trustee May Enforce Claims Without Possession of Securities.........49
Section 5.6     Application of Money Collected......................................49
Section 5.7     Limitation on Suits.................................................50
Section 5.8     Unconditional Right of Holders to Receive Principal, Premium
                and Interest and to Convert.........................................50
Section 5.9     Restoration of Rights and Remedies..................................51
Section 5.10    Rights and Remedies Cumulative......................................51
Section 5.11    Delay or Omission Not Waiver........................................51
Section 5.12    Control by Holders of Securities....................................51
Section 5.13    Waiver of Past Defaults.............................................51
Section 5.14    Undertaking for Costs...............................................52
Section 5.15    Waiver of Stay, Usury or Extension Laws.............................52

                             ARTICLE VI THE TRUSTEE

Section 6.1     Certain Duties and Responsibilities.................................52
Section 6.2     Notice of Defaults..................................................53
Section 6.3     Certain Rights of Trustee...........................................54
Section 6.4     Not Responsible for Recitals or Issuance of Securities..............55
Section 6.5     May Hold Securities, Act as Trustee under Other Indentures..........55
Section 6.6     Money Held in Trust.................................................55
Section 6.7     Compensation and Reimbursement......................................55
Section 6.8     Corporate Trustee Required; Eligibility.............................56
Section 6.9     Resignation and Removal; Appointment of Successor...................56
Section 6.10    Acceptance of Appointment by Successor..............................57
Section 6.11    Merger, Conversion, Consolidation or Succession to Business.........58
Section 6.12    Authenticating Agents...............................................58
Section 6.13    Disqualification; Conflicting Interests.............................59
Section 6.14    Preferential Collection of Claims Against Company...................59

           ARTICLE VII CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR
                                     LEASE

Section 7.1     Company May Consolidate, Etc., Only on Certain Terms................60
Section 7.2     Successor Substituted...............................................60
</TABLE>

                                       ii
<PAGE>   5

<TABLE>
<S>             <C>                                                               <C>
                      ARTICLE VIII SUPPLEMENTAL INDENTURES

Section 8.1     Supplemental Indentures Without Consent of Holders of
                Securities..........................................................61
Section 8.2     Supplemental Indentures with Consent of Holders of Securities.......62
Section 8.3     Execution of Supplemental Indentures................................63
Section 8.4     Effect of Supplemental Indentures...................................63
Section 8.5     Reference in Securities to Supplemental Indentures..................63
Section 8.6     Notice of Supplemental Indentures...................................63

                  ARTICLE IX MEETINGS OF HOLDERS OF SECURITIES

Section 9.1     Purposes for Which Meetings May Be Called...........................63
Section 9.2     Call, Notice and Place of Meetings..................................63
Section 9.3     Persons Entitled to Vote at Meetings................................64
Section 9.4     Quorum; Action......................................................64
Section 9.5     Determination of Voting Rights; Conduct and Adjournment of
                Meetings............................................................65
Section 9.6     Counting Votes and Recording Action of Meetings.....................65

                               ARTICLE X COVENANTS

Section 10.1    Payment of Principal, Premium and Interest..........................66
Section 10.2    Maintenance of Offices or Agencies..................................66
Section 10.3    Money for Security Payments to Be Held in Trust.....................67
Section 10.4    Existence...........................................................68
Section 10.5    Maintenance of Properties...........................................68
Section 10.6    Payment of Taxes and Other Claims...................................68
Section 10.7    Statement by Officers as to Default.................................69
Section 10.8    Waiver of Certain Covenants.........................................69

                       ARTICLE XI REDEMPTION OF SECURITIES

Section 11.1    Right of Redemption.................................................69
Section 11.2    Applicability of Article............................................69
Section 11.3    Election to Redeem; Notice to Trustee...............................69
Section 11.4    Selection by Trustee of Securities to Be Redeemed...................70
Section 11.5    Notice of Redemption................................................70
Section 11.6    Deposit of Redemption Price.........................................71
Section 11.7    Securities Payable on Redemption Date...............................71
Section 11.8    Conversion Arrangement on Call for Redemption.......................72

                      ARTICLE XII CONVERSION OF SECURITIES

Section 12.1    Conversion Privilege and Conversion Rate............................73
Section 12.2    Exercise of Conversion Privilege....................................73
Section 12.3    Fractions of Shares.................................................74
Section 12.4    Adjustment of Conversion Rate.......................................74
</TABLE>

                                      iii
<PAGE>   6

<TABLE>
<S>             <C>                                                               <C>
Section 12.5    Notice of Adjustments of Conversion Rate............................79
Section 12.6    Notice of Certain Corporate Action..................................79
Section 12.7    Company to Reserve Common Stock.....................................80
Section 12.8    Taxes on Conversions................................................80
Section 12.9    Covenant as to Common Stock.........................................81
Section 12.10   Cancellation of Converted Securities................................81
Section 12.11   Provision in Case of Consolidation, Merger or Sale of Assets........81
Section 12.12   Rights Issued in Respect of Common Stock............................82
Section 12.13   Responsibility of Trustee for Conversion Provisions.................82

                    ARTICLE XIII SUBORDINATION OF SECURITIES

Section 13.1    Securities Subordinate to Senior Debt...............................83
Section 13.2    No Payment in Certain Circumstances, Payment over of
                Proceeds upon Dissolution, Etc .....................................83
Section 13.3    Prior Payment to Senior Debt upon Acceleration of Securities........85
Section 13.4    Payment Permitted If No Default.....................................85
Section 13.5    Subrogation to Rights of Holders of Senior Debt.....................86
Section 13.6    Provisions Solely to Define Relative Rights.........................86
Section 13.7    Trustee to Effectuate Subordination.................................86
Section 13.8    No Waiver of Subordination Provisions...............................86
Section 13.9    Notice to Trustee...................................................87
Section 13.10   Reliance on Judicial Order or Certificate of Liquidating Agent......87
Section 13.11   Trustee Not Fiduciary for Holders of Senior Debt....................88
Section 13.12   Reliance by Holders of Senior Debt on Subordination
                Provisions..........................................................88
Section 13.13   Rights of Trustee as Holder of Senior Debt; Preservation of
                Trustee's Rights....................................................88
Section 13.14   Article Applicable to Paying Agents.................................88
Section 13.15   Certain Conversions and Repurchases Deemed Payment..................88

            ARTICLE XIV REPURCHASE OF SECURITIES AT THE OPTION OF THE
                        HOLDER UPON A CHANGE IN CONTROL

Section 14.1    Right to Require Repurchase.........................................89
Section 14.2    Conditions to the Company's Election to Pay the Repurchase
                Price in Common Stock...............................................90
Section 14.3    Notices; Method of Exercising Repurchase Right, Etc.................90
Section 14.4    Certain Definitions.................................................93
Section 14.5    Consolidation, Merger, Etc..........................................94

          ARTICLE XV HOLDERS LISTS AND REPORTS BY TRUSTEE AND COMPANY;
                                  NON-RECOURSE

Section 15.1    Company to Furnish Trustee Names and Addresses of Holders...........95
Section 15.2    Preservation of Information.........................................95
Section 15.3    Reports by Trustee..................................................96
</TABLE>

                                       iv
<PAGE>   7

<TABLE>
<S>             <C>                                                               <C>
Section 15.4    Reports by Company..................................................96

          ARTICLE XVI IMMUNITY OF INCORPORATORS, STOCKHOLDERS, OFFICERS
                                 AND DIRECTORS

Section 16.1    Indenture and Securities Solely Corporate Obligations...............96

EXHIBIT A      Form of Certificate..................................................A-1
EXHIBIT B      Form of Certificate to Be Delivered in Connection with Transfers
               Pursuant to Non-QIB Accredited Investors.............................B-1
EXHIBIT C      Form of Certificate to Be Delivered in Connection with Transfers
               Pursuant to Regulation S.............................................C-1
</TABLE>

                                       v
<PAGE>   8

          INDENTURE, dated as of June 28, 2000, between ALLIED RISER
COMMUNICATIONS CORPORATION, a corporation duly organized and existing under the
laws of the State of Delaware, having its principal office at 1700 Pacific
Avenue, Suite 400, Dallas, Texas 75201 (herein called the "Company"), and
WILMINGTON TRUST COMPANY, a banking corporation, as Trustee hereunder (herein
called the "Trustee").

                             RECITALS OF THE COMPANY

          The Company has duly authorized the creation of an issue of its 7.50%
Convertible Subordinated Notes due 2007 (herein called the "Securities") of
substantially the tenor and amount hereinafter set forth, and to provide
therefor the Company has duly authorized the execution and delivery of this
Indenture.

          All things necessary to make the Securities, when the Securities are
executed by the Company and authenticated and delivered hereunder, the valid
obligations of the Company, and to make this Indenture a valid agreement of the
Company, in accordance with their and its terms, have been done. Further, all
things necessary to duly authorize the issuance of the Common Stock of the
Company issuable upon the conversion of the Securities, and to duly reserve for
issuance the number of shares of Common Stock issuable upon such conversion,
have been done.

          This Indenture is subject to, and shall be governed by, the provisions
of the Trust Indenture Act of 1939, as amended, that are required to be a part
of and to govern indentures qualified under the Trust Indenture Act of 1939, as
amended.

                   NOW, THEREFORE, THIS INDENTURE WITNESSETH:

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

                                   ARTICLE I

             DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

          SECTION 1.1 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 accounting terms not otherwise defined herein have the
     meanings assigned to them in accordance with generally accepted accounting
     principles in the United States, and, except as otherwise herein expressly
     provided, the term "generally accepted

                                       1
<PAGE>   9

     accounting principles" with respect to any computation required or
     permitted hereunder shall mean such accounting principles as are generally
     accepted at the date of such computation; and

          (3) 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.

          "Act", when used with respect to any Holder of a Security, has the
meaning specified in Section 1.4.

          "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.

          "Agent Member" means any member of, or participant in, the Depositary.

          "Applicable Procedures" means, with respect to any transfer or
transaction involving a Global Security or beneficial interest therein, the
rules and procedures of The Depository Trust Company or any successor
Depository, in each case to the extent applicable to such transaction and as in
effect from time to time.

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

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

          "Board Resolution" means a resolution duly adopted by the Board of
Directors, a copy of which, 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, shall have been
delivered to the Trustee.

          "Business Day", when used with respect to any Place of Payment, Place
of Conversion or any other place, as the case may be, means each Monday,
Tuesday, Wednesday, Thursday and Friday which is not a day on which banking
institutions in such Place of Payment, Place of Conversion or other place, as
the case may be, are authorized or obligated by law or executive order to close;
provided, however, that a day on which banking institutions in New York, New
York are authorized or obligated by law or executive order to close shall not be
a Business Day for purposes of Section 13.9.

          "Change in Control" has the meaning specified in Section 14.4(2).

          "Closing Price Per Share" means, with respect to the Common Stock, for
any day, the reported last sale price on such day or in case no sale takes place
on such day, the average of

                                       2
<PAGE>   10

the reported closing bid and asked prices on the principal national securities
exchange on which such Common Stock is listed or admitted to trading or, if not
listed or admitted to trading on any national securities exchange, the average
of the closing bid and asked prices as furnished by any independent registered
broker-dealer firm, selected by the Company for that purpose, in each case
adjusted for any stock split during the relevant period.

          "Code" has the meaning specified in Section 2.l.

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

          "Common Stock" means the Common Stock, par value $0.0001 per share, of
the Company authorized at the date of this instrument as originally executed.
Subject to the provisions of Section 12.11, shares issuable on conversion or
repurchase of Securities shall include only shares of Common Stock or shares of
any class or classes of common stock resulting from any reclassification or
reclassifications thereof; provided, however, that if at any time there shall be
more than one such resulting class, the shares so issuable on conversion of
Securities shall include shares of all such classes, and the shares of each such
class then so issuable shall be substantially in the proportion which the total
number of shares of such class resulting from all such reclassifications bears
to the total number of shares of all such classes resulting from all such
reclassifications.

          "common stock" includes any stock of any class of capital stock which
has no preference in respect of dividends or of amounts payable in the event of
any voluntary or involuntary liquidation, dissolution or winding up of the
issuer thereof and which is not subject to redemption by the issuer thereof.

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

          "Company Notice" has the meaning specified in Section 14.3.

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

          "Constituent Person" has the meaning specified in Section 12.11.

          "Conversion Agent" means any Person authorized by the Company to
convert Securities in accordance with Article XII. The Company has initially
appointed the Trustee as its Conversion Agent pursuant to Section 10.2 hereof.

          "Conversion Price" has the meaning specified in Section 14.4(3).

                                       3
<PAGE>   11
          "Conversion Rate" has the meaning specified in Section 12.1.

          "Conversion Share" means shares of Common Stock of the Company
issuable upon conversion of a Security.

          "Corporate Trust Office" means the office of the Trustee at which at
any particular time the trust created by this Indenture shall be principally
administered (which at the date of this Indenture is located at 1100 North
Market Street, Rodney Square North, Wilmington, DE 19890, Attention: Corporate
Trust Administration (Allied Riser Communications Corporation, 7.50% Convertible
Subordinated Notes due 2007)).

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

          "Defaulted Interest" has the meaning specified in Section 3.9.

          "Depositary" means, with respect to any Securities (including any
Global Securities), a clearing agency that is registered as such under the
Exchange Act and is designated by the Company to act as Depositary for such
Securities (or any successor securities clearing agency so registered).

          "Designated Senior Debt" means the Company's obligations under any
particular Senior Debt in which the instrument creating or evidencing the same
or the assumption or guarantee thereof (or related agreements or documents to
which the Company is a party) expressly provides that such Senior Debt shall be
"Designated Senior Debt" for purposes of this Indenture (provided that such
instrument, agreement or other document may place limitations and conditions on
the right of such Senior Debt to exercise the rights of Designated Senior Debt).

          "Distribution Date" shall mean the "Distribution Date" as such term is
defined in the Registration Rights Agreement.

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

          "DTC" means The Depository Trust Company, a New York corporation.

          "Event of Default" has the meaning specified in Section 5.1.

          "Exchange Act" means the United States Securities Exchange Act of 1934
(or any successor statute), as amended from time to time.

          "Global Security" has the meanings specified in Section 2.1.

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

                                       4
<PAGE>   12

          "Indenture" means this instrument as originally executed or as it may
from time to time be supplemented or amended by one or more indentures
supplemental hereto entered into pursuant to the applicable provisions hereof,
including, for all purposes of this instrument and any such supplemental
indenture, the provisions of the Trust Indenture Act that are deemed to be a
part of and govern this instrument and any such supplemental indenture,
respectively.

          "Initial Purchaser" means Goldman, Sachs & Co.

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

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

          "Issue Date" means June 28, 2000.

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

          "Non-electing Share" has the meaning specified in Section 12.11.

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

          "Notice of Default" has the meaning specified in Section 5.1.

          "Offshore Global Security" has the meaning specified in Section 2.2.

          "Offshore Physical Security" has the meaning specified in Section 2.2.

          "Officers' Certificate" means a certificate signed by (i) the Chairman
of the Board, a Vice Chairman of the Board, the Chief Executive Officer, the
President, an Executive Vice President or a Vice President and by (ii) the
principal financial officer, the Treasurer, an Assistant Treasurer, the
Secretary or an Assistant Secretary of the Company, and delivered to the
Trustee. One of the Officers signing an Officers' Certificate given pursuant to
Section 10.7 shall be the principal executive, financial or accounting officer
of the Company.

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

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

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

                                       5
<PAGE>   13

          (ii) Securities for the payment or redemption of which 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 3.8 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 Article XII;

provided, however, that in determining whether the Holders of the requisite
principal amount of Outstanding Securities are present at a meeting of Holders
of Securities for quorum purposes or have given any request, demand,
authorization, direction, notice, consent or waiver hereunder, Securities owned
by the Company or any other obligor upon the Securities or any Affiliate of the
Company or such other obligor shall be disregarded and deemed not to be
Outstanding, except that, in determining whether the Trustee shall be protected
in relying upon any such determination as to the presence of a quorum or upon
any such request, demand, authorization, direction, notice, consent or waiver,
only Securities which a Responsible Officer of the Trustee has been notified in
writing 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 is not
the Company or any other obligor upon the Securities or any Affiliate of the
Company or such other obligor, and the Trustee shall be protected in relying
upon an Officer's Certificate to such effect.

          "Over-allotment Option" has the meaning specified in Section 3.1.

          "Paying Agent" means any Person authorized by the Company to pay the
principal of or interest on any Securities on behalf of the Company and, except
as otherwise specifically set forth herein, such term shall include the Company
if it shall act as its own Paying Agent. The Company has initially appointed the
Trustee as its Paying Agent pursuant to Section 10.2 hereof.

          "Payment Blockage Notice" has the meaning specified in Section 13.2.

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

          "Physical Securities" has the meaning specified in Section 2.1.

          "Place of Conversion" has the meaning specified in Section 3.1.

          "Place of Payment" has the meaning specified in Section 3.1.

                                       6
<PAGE>   14

          "Predecessor Security" of any particular Security means every previous
Security evidencing all or a portion of the same debt as that evidenced by such
particular Security; and, for the purposes of this definition, any Security
authenticated and delivered under Section 3.8 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.

          "Press Release" means any press release issued by the Company and
disseminated to Reuters Business News Services and Bloomberg News Services.

          "Private Placement Legend" means the legend initially set forth in
Section 3.4.

          "Purchase Agreement" means the Purchase Agreement, dated as of June
22, 2000, between the Company and the Initial Purchaser, as such agreement may
be amended from time to time.

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

          "Record Date" means any Regular Record Date or Special Record Date.

          "Record Date Period" means the period from the close of business of
any Regular Record Date next preceding any Interest Payment Date to the opening
of business on such Interest Payment Date.

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

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

          "Registration Rights Agreement" means the Registration Rights
Agreement dated June 22, 2000 between the Company and the Initial Purchaser.

          "Regular Record Date" for interest payable in respect of any Security
on any Interest Payment Date means the June 1 or December 1 (whether or not a
Business Day), as the case may be, next preceding such Interest Payment Date.

          "Representative" means the (a) indenture trustee or other trustee,
agent or representative for any Senior Debt or (b) with respect to any Senior
Debt that does not have any such trustee, agent or other representative, (i) in
the case of such Senior Debt issued pursuant to an agreement providing for
voting arrangements as among the holders or owners of such Senior Debt, any
holder or owner of such Senior Debt acting with the consent of the required
persons necessary to bind such holders or owners of such Senior Debt and (ii) in
the case of all other such Senior Debt, the holder or owner of such Senior Debt.

          "Repurchase Date" has the meaning specified in Section 14.1.

          "Repurchase Price" has the meaning specified in Section 14.1.

                                       7
<PAGE>   15

          "Responsible Officer", when used with respect to the Trustee, means
any officer within the Corporate Trust Office of the Trustee with direct
responsibility for the administration of this Indenture and also means, with
respect to a particular corporate trust matter, any other officer to whom such
matter is referred because of his knowledge and familiarity with the particular
subject.

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

          "Securities" has the meaning ascribed to it in the first paragraph
under the caption "Recitals of the Company".

          "Securities Act" means the United States Securities Act of 1933 (or
any successor statute), as amended from time to time.

          "Security Register" and "Security Registrar" have the respective
meanings specified in Section 3.5.

          "Senior Debt" means the principal of (and premium, if any) and
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) on, and all fees and
other amounts payable in connection with, the following, whether absolute or
contingent, secured or unsecured, due or to become due, outstanding on the date
of this Indenture or thereafter created, incurred or assumed: (a) indebtedness
of the Company evidenced by a credit or loan agreement, note, bond, debenture or
other written obligation, (b) all obligations of the Company for money borrowed,
(c) all obligations of the Company evidenced by a note or similar instrument
given in connection with the acquisition of any businesses, properties or assets
of any kind, (d) obligations of the Company (i) as lessee under leases required
to be capitalized on the balance sheet of the lessee under generally accepted
accounting principles and (ii) as lessee under other leases for facilities,
capital equipment or related assets, whether or not capitalized, entered into or
leased for financing purposes, (e) all obligations of the Company under interest
rate and currency swaps, caps, floors, collars, hedge agreements, forward
contracts or similar agreements or arrangements, (f) all obligations of the
Company with respect to letters of credit, bankers' acceptances and similar
facilities (including reimbursement obligations with respect to the foregoing),
(g) all obligations of the Company issued or assumed as the deferred purchase
price of property or services (but excluding trade accounts payable and accrued
liabilities arising in the ordinary course of business), (h) all obligations of
the type referred to in clauses (a) through (g) above of another Person and all
dividends of another Person, the payment of which, in either case, the Company
has assumed or guaranteed, or for which the Company is responsible or liable,
directly or indirectly, jointly or severally, as obligor, guarantor or
otherwise, or which is secured by a lien on the property of the Company, and (i)
renewals, extensions, modifications, replacements, restatements and refundings
of, or any indebtedness or obligation issued in exchange for, any such
indebtedness or obligation described in clauses (a) through (h) of this
paragraph; provided, however, that Senior Debt shall not include any such
indebtedness or obligation if the terms of such indebtedness or obligation (or
the terms of the instrument under which, or pursuant to which it is issued)
expressly provide that such indebtedness or obligation is not superior in right
of payment to the Securities.

                                       8
<PAGE>   16

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

          "Significant Subsidiary" means, with respect to any Person, a
Subsidiary of such Person that would constitute a "significant subsidiary" as
such term is defined under Rule 1-02 of Regulation S-X under the Securities Act
and the Exchange Act.

          "Special Record Date" for the payment of any Defaulted Interest means
a date fixed by the Company pursuant to Section 3.9.

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

          "Subsidiary" means a corporation more than 50% of the outstanding
voting stock of which is owned, directly or indirectly, by the Company or by one
or more other Subsidiaries, or by the Company and one or more other
Subsidiaries. For the purposes of this definition, "voting stock" means stock or
other similar interests in the corporation which ordinarily has or have voting
power for the election of directors, or persons performing similar functions,
whether at all times or only so long as no senior class of stock or other
interests has or have such voting power by reason of any contingency.

          "Successor Security" of any particular Security means every Security
issued after, and evidencing all or a portion of the same debt as that evidenced
by, such particular Security; and, for the purposes of this definition, any
Security authenticated and delivered under Section 3.8 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.

          "Trading Day" means, in respect of any securities exchange or
securities market, each Monday, Tuesday, Wednesday, Thursday and Friday, other
than any day on which securities are not traded on the applicable securities
exchange or in the applicable securities market.

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

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

          "U.S. Global Security" has the meaning specified in Section 2.2.

          "U.S. Physical Security" has the meaning specified in Section 2.2.

                                       9
<PAGE>   17

          "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 (its "possessions" including Puerto Rico, the
U.S. Virgin Islands, Guam, American Samoa, Wake Island and the Northern Mariana
Islands).

          SECTION 1.2 COMPLIANCE CERTIFICATES AND OPINIONS. Upon any application
or request by the Company to the Trustee to take any action under any provision
of this Indenture, the Company shall furnish to the Trustee 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
furnished.

          Every certificate or opinion with respect to compliance with a
condition or covenant provided for in this Indenture (including certificates
provided for in Section 10.7) shall include:

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

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

          (3) a statement that, in the opinion of such individual, he has made
     such examination or investigation as is necessary to enable him to express
     an informed opinion as to whether or not such covenant or condition has
     been complied with; and

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

          SECTION 1.3 FORM OF DOCUMENTS DELIVERED TO THE TRUSTEE

          In any case where several matters are required to be certified by, or
covered by an opinion of, any specified Person, it is not necessary that all
such matters be certified by, or covered by the opinion of, only one such
Person, or that they be so certified or covered by only one document, but one
such Person may certify or give an opinion with respect to some matters and one
or more other such Persons as to other matters, and any such Person may certify
or give an opinion as to such matters in one or several documents. Any
certificate or opinion of an officer of the Company may be based, insofar as it
relates to legal matters, upon a certificate or opinion of, or representations
by, counsel, unless such officer knows, or in the exercise of reasonable care
should know, that the certificate or opinion or representations with respect to
the matters upon which such certificate or opinion is based are erroneous. Any
such certificate or opinion of counsel may be based, insofar as it relates to
factual matters, upon a certificate or opinion of, or representations by, an
officer or officers of the Company or any other Person stating that the
information with respect to such factual matters is in the possession of the
Company or such other Person, unless such counsel knows, or in the exercise of
reasonable care should know, that the certificate or opinion or representations
with respect to such matters are erroneous.

                                       10
<PAGE>   18

          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 1.4 ACTS OF HOLDERS OF SECURITIES.

          (1) Any request, demand, authorization, direction, notice, consent,
waiver or other action provided or permitted by this Indenture to be given or
taken by Holders of Securities may be embodied in and evidenced by (A) one or
more instruments of substantially similar tenor signed by such Holders in person
or by an agent or proxy duly appointed in writing by such Holders or (B) the
record of Holders of Securities voting in favor thereof, either in person or by
proxies duly appointed in writing, at any meeting of Holders of Securities duly
called and held in accordance with the provisions of Article IX. Such action
shall become effective when such instrument or instruments or record is
delivered to the Trustee and, where it is hereby expressly required, to the
Company. The Trustee shall, within a reasonable time period, deliver to the
Company copies of all such instruments and records delivered to the Trustee.
Such instrument or instruments and records (and the action embodied therein and
evidenced thereby) are herein sometimes referred to as the "Act" of the Holders
of Securities signing such instrument or instruments and so voting at such
meeting. Proof of execution of any such instrument or of a writing appointing
any such agent or proxy, or of the holding by any Person of a Security, shall be
sufficient for any purpose of this Indenture and (subject to Section 6.1)
conclusive in favor of the Trustee and the Company if made in the manner
provided in this Section. The record of any meeting of Holders of Securities
shall be proved in the manner provided in Section 9.6.

          (2) 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.

          (3) The principal amount and serial number of any Security held by any
Person, and the date of his holding the same, shall be proved by the Security
Register.

          (4) The fact and date of execution of any such instrument or writing
and the authority of the Person executing the same may also be proved in any
other manner which the Trustee deems sufficient; and the Trustee may in any
instance require further proof with respect to any of the matters referred to in
this Section 1.4.

          (5) The Company may set any day as the record date for the purpose of
determining the Holders entitled to give or take any request, demand,
authorization, direction, notice, consent, waiver or other action, or to vote on
any action, authorized or permitted by this Indenture to be given or taken by
Holders. Promptly and in any case not later than ten days after setting a record
date, the Company shall notify the Trustee and the Holders of such record date.

                                       11
<PAGE>   19

If not set by the Company prior to the first solicitation of a Holder made by
any Person in respect of any such action, or, in the case of any such vote,
prior to such vote, the record date for any such action or vote shall be the
30th day (or, if later, the date of the most recent list of Holders required to
be provided pursuant to Section 15.1) prior to such first solicitation or vote,
as the case may be. With regard to any record date, the Holders on such date (or
their duly appointed agents or proxies), and only such Persons, shall be
entitled to give or take, or vote on, the relevant action, whether or not such
Holders remain Holders after such record date. Notwithstanding the foregoing,
the Company shall not set a record date for, and the provisions of this
paragraph shall not apply with respect to, any notice, declaration or direction
referred to in the next paragraph.

          Upon receipt by the Trustee from any Holder of (i) any notice of
default or breach referred to in Section 5.1(4), if such default or breach has
occurred and is continuing and the Trustee shall not have given such a notice to
the Company, (ii) any declaration of acceleration referred to in Section 5.2, if
an Event of Default has occurred and is continuing and the Trustee shall not
have given such a declaration to the Company, or (iii) any direction referred to
in Section 5.12, if the Trustee shall not have taken the action specified in
such direction, then, with respect to clauses (ii) and (iii), a record date
shall automatically and without any action by the Company or the Trustee be set
for determining the Holders entitled to join in such declaration or direction,
which record date shall be the close of business on the tenth day (or, if such
day is not a Business Day, the first Business Day thereafter) following the day
on which the Trustee receives such declaration or direction, and, with respect
to clause (i), the Trustee may set any day as a record date for the purpose of
determining the Holders entitled to join in such notice of default. Within a
reasonable time period after such receipt by the Trustee of any such declaration
or direction referred to in clause (ii) or (iii), and promptly after setting any
record date with respect to clause (i), and as soon as practicable thereafter,
the Trustee shall notify the Company and the Holders of any such record date so
fixed. The Holders on such record date (or their duly appointed agents or
proxies), and only such Persons, shall be entitled to join in such notice,
declaration or direction, whether or not such Holders remain Holders after such
record date; provided that, unless such notice, declaration or direction shall
have become effective by virtue of Holders of the requisite principal amount of
Securities on such record date (or their duly appointed agents or proxies)
having joined therein on or prior to the 90th day after such record date, such
notice, declaration or direction shall automatically and without any action by
any Person be canceled and of no further effect. Nothing in this paragraph shall
be construed to prevent a Holder (or a duly appointed agent or proxy thereof)
from giving, before or after the expiration of such 90-day period, a notice,
declaration or direction contrary to or different from, or, after the expiration
of such period, identical to, the notice, declaration or direction to which such
record date relates, in which event a new record date in respect thereof shall
be set pursuant to this paragraph. In addition, nothing in this paragraph shall
be construed to render ineffective any notice, declaration or direction of the
type referred to in this paragraph given at any time to the Trustee and the
Company by Holders (or their duly appointed agents or proxies) of the requisite
principal amount of Securities on the date such notice, declaration or direction
is so given.

          (6) Except as provided in Sections 5.12 and 5.13, any request, demand,
authorization, direction, notice, consent, election, 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

                                       12
<PAGE>   20

issued upon the registration of transfer thereof or in exchange therefor or in
lieu thereof in respect of anything done, omitted or suffered to be done by the
Trustee or the Company in reliance thereon, whether or not notation of such
action is made upon such Security.

          (7) The provisions of this Section 1.4 are subject to the provisions
of Section 9.5.

          SECTION 1.5 NOTICES, ETC. TO THE TRUSTEE AND COMPANY. Any request,
demand, authorization, direction, notice, consent, election, waiver or other Act
of Holders of Securities or other document provided or permitted by this
Indenture to be made upon, given or furnished to, or filed with,

          (i) the Trustee by any Holder of Securities or by the Company shall be
     sufficient for every purpose hereunder if made, given, furnished or filed
     in writing to or with a Responsible Officer of the Trustee and received at
     its Corporate Trust Office, Attention: Corporate Trust Administration
     (Allied Riser Communications Corporation, 7.50% Convertible Subordinated
     Notes due 2007); or

          (ii) the Company by the Trustee or by any Holder of Securities shall
     be sufficient for every purpose hereunder (unless otherwise herein
     expressly provided) if in writing, mailed, first-class postage prepaid, or
     telecopied and confirmed by mail, first-class postage prepaid, or delivered
     by hand or overnight courier, addressed to the Company at 1700 Pacific
     Avenue, Suite 400, Dallas, Texas 75201, Attention: General Counsel, or at
     any other address previously furnished in writing to the Trustee by the
     Company.

          SECTION 1.6 NOTICE TO HOLDERS OF SECURITIES; WAIVER. Except as
otherwise expressly provided herein, where this Indenture provides for notice to
Holders of Securities of any event, such notice shall be sufficiently given to
Holders if in writing and mailed, first-class postage prepaid or delivered by an
overnight delivery service, to each Holder of a Security affected by such event,
at the address of such Holder as it appears in the Security Register, not
earlier than the earliest date and not later than the latest date prescribed for
the giving of such notice.

          Neither the failure to mail such notice, nor any defect in any notice
so mailed, to any particular Holder of a Security shall affect the sufficiency
of such notice with respect to other Holders of Securities. In case by reason of
the suspension of regular mail service or by reason of any other cause it shall
be impracticable to give such notice by mail, then such notification to Holders
of Securities as shall be made with the approval of the Trustee, which approval
shall not be unreasonably withheld, shall constitute a sufficient notification
to such Holders for every purpose hereunder.

          Such notice shall be deemed to have been given when such notice is
mailed.

          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 of Securities 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.

                                       13
<PAGE>   21

          SECTION 1.7 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 1.8 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 1.9 SEPARABILITY CLAUSE. In case any provision in this
Indenture or the Securities shall be invalid, illegal or unenforceable, the
validity, legality and enforceability of the remaining provisions shall not in
any way be affected or impaired thereby.

          SECTION 1.10 BENEFITS OF INDENTURE. Except as provided in the next
sentence, nothing in this Indenture or in the Securities, express or implied,
shall give to any Person, other than the parties hereto and their successors
assigns hereunder and the Holders of Securities, any benefit or legal or
equitable right, remedy or claim under this Indenture. The provisions of Article
XIII are intended to be for the benefit of, and shall be enforceable directly
by, the holders of Senior Debt.

          SECTION 1.11 GOVERNING LAW. THIS INDENTURE AND THE SECURITIES SHALL BE
GOVERNED BY THE LAWS OF THE STATE OF NEW YORK.

          SECTION 1.12 LEGAL HOLIDAYS. In any case where any Interest Payment
Date, Redemption Date, Repurchase Date or Stated Maturity of any Security or the
last day on which a Holder of a Security has a right to convert his Security
shall not be a Business Day at a Place of Payment or Place of Conversion, as the
case may be, then (notwithstanding any other provision of this Indenture or of
the Securities) payment of principal of, premium, if any, or interest on, or the
payment of the Redemption Price or Repurchase Price (whether the same is payable
in cash or in shares of Common Stock that have been registered under the
Securities Act in the case of the Repurchase Price) with respect to, or delivery
for conversion of, such Security need not be made at such Place of Payment or
Place of Conversion, as the case may be, on or by such day, but may be made on
or by the next succeeding Business Day at such Place of Payment or Place of
Conversion, as the case may be, with the same force and effect as if made on the
Interest Payment Date, Redemption Date or Repurchase Date, or at the Stated
Maturity or by such last day for conversion; provided, however, that in the case
that payment is made on such succeeding Business Day, 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 last day for
conversion, as the case may be.

          SECTION 1.13 CONFLICT WITH TRUST INDENTURE ACT. If any provision
hereof limits, qualifies or conflicts with a provision of the Trust Indenture
Act that is required under such Act to be a part of and govern this Indenture,
the latter provision shall control. If any provision of this Indenture modifies
or excludes any provision of the Trust Indenture Act that may be so modified or
excluded, the latter provision shall be deemed to apply to this Indenture as so
modified or to be excluded, as the case may be. Until such time as this
Indenture shall be qualified under the Trust Indenture Act, this Indenture, the
Company and the Trustee shall be deemed for all purposes hereof to be subject to
and governed by the Trust Indenture Act to the same extent as would be the case
if this Indenture were so qualified on the date hereof.

                                       14
<PAGE>   22

                                   ARTICLE II
                                 SECURITY FORMS

          SECTION 2.1 FORM GENERALLY. The Securities shall be in substantially
the form set forth in this Article, with such appropriate insertions, omissions,
substitutions and other variations as are required or permitted by this
Indenture, and may have such letters, numbers or other marks of identification
and such legends or endorsements placed thereon as may be required to comply
with the rules of any securities exchange, the Internal Revenue Code of 1986, as
amended, and regulations thereunder (the "Code"), or as may, consistent
herewith, be determined by the officers executing such Securities, as evidenced
by their execution thereof. All Securities shall be in fully registered form.

          The Trustee's certificates of authentication shall be in substantially
the form set forth in Section 2.3.

          Conversion notices shall be in substantially the form set forth in
Section 2.4.

          Repurchase notices shall be substantially in the form set forth in
Section 2.2.

          Securities offered and sold in reliance on Rule 144A shall be issued
initially in the form of one or more permanent global Securities in registered
form, substantially in the form set forth in Section 2.2 (the "U.S. Global
Securities"), registered in the name of the nominee of the Depositary, deposited
with the Trustee, as custodian for the Depositary, duly executed by the Company
and authenticated by the Trustee as hereinafter provided. The aggregate
principal amount of the U.S. Global Securities may from time to time be
increased or decreased by adjustments made on the records of the Trustee, as
custodian for the Depositary, or its nominee, in accordance with the
instructions given by the Holder thereof, as hereinafter provided.

          Securities offered and sold in offshore transaction in reliance on
Regulation S shall be issued in the form of permanent global Securities in
registered form substantially in the form recited above (the "Offshore Global
Securities") deposited with the Trustee, as custodian for the Depositary, duly
executed by the Company and authenticated by the Trustee as hereinafter
provided. The aggregate principal amount of the Offshore Global Security may
from time to time be increased or decreased by adjustments made in the records
of the Trustee, as custodian for the Depositary or its nominee, as herein
provided.

          Securities issued pursuant to Section 3.6 in exchange for interests in
the U.S. Global Securities and Offshore Global Securities shall be in the form
of permanent certificated Securities in registered form substantially in the
form set forth in Section 2.2 hereto (the "U.S. Physical Securities" and the
"Offshore Physical Securities," respectively).

          The Offshore Physical Securities and U.S. Physical Securities are
sometimes collectively herein referred to as the "Physical". The U.S. Global
Securities and the Offshore Global Securities are sometimes referred to as the
"Global Securities."

                                       15
<PAGE>   23

          The definitive Securities shall be printed, lithographed, typewritten
or engraved or produced by any combination of these methods or may be produced
in any other manner permitted by the rules of any automated quotation system or
securities exchange (including on steel engraved borders if so required by any
securities exchange upon which the Securities may be listed) on which the
Securities may be quoted or listed, as the case may be, all as determined by the
officers executing such Securities, as evidenced by their execution thereof.

          SECTION 2.2 FORM OF SECURITY.

                                 [FORM OF FACE]

          [THE FOLLOWING LEGEND SHALL APPEAR ON THE FACE OF EACH GLOBAL
SECURITY:

          UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE
OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), 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
ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC OR SUCH OTHER
REPRESENTATIVE OF DTC OR 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 INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST
HEREIN.

          TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS IN
WHOLE, BUT NOT IN PART, TO NOMINEES OF CEDE & CO. OR TO A SUCCESSOR THEREOF OR
SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL SECURITY SHALL
BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN
SECTION 3.7 OF THE INDENTURE.

          THIS NOTE AND ANY COMMON STOCK ISSUABLE UPON THE CONVERSION OF THIS
NOTE HAVE NOT BEEN AND WILL NOT BE REGISTERED UNDER THE U.S. SECURITIES ACT OF
1933, AS AMENDED (THE "SECURITIES ACT"), AND ACCORDINGLY, MAY NOT BE SOLD OR
OTHERWISE TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE
EXEMPTION THEREFROM. EACH PURCHASER OF THIS NOTE IS HEREBY NOTIFIED THAT THE
SELLER OF THIS NOTE MAY BE RELYING ON THE EXEMPTION FROM THE PROVISIONS OF
SECTION 5 OF THE SECURITIES ACT PROVIDED BY RULE 144A THEREUNDER. BY ITS
ACQUISITION HEREOF, THE HOLDER (1) REPRESENTS THAT IT IS A "QUALIFIED
INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) OR (B)
IT IS NOT A U.S. PERSON AND IS ACQUIRING THIS NOTE IN AN OFFSHORE TRANSACTION IN
COMPLIANCE WITH REGULATION S UNDER THE SECURITIES ACT, (2) AGREES THAT IT WILL
NOT RESELL OR OTHERWISE

                                       16
<PAGE>   24

TRANSFER THE NOTE EVIDENCED HEREBY OR THE COMMON STOCK ISSUABLE UPON CONVERSION
OF SUCH NOTE WITHIN THE TIME PERIOD REFERRED TO IN RULE 144(k) (TAKING INTO
ACCOUNT THE PROVISIONS OF RULE 144(d) IN THE CASE OF SUCH STOCK) EXCEPT (A) TO
THE COMPANY OR ANY SUBSIDIARY THEREOF, (B) INSIDE THE UNITED STATES TO A
QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A UNDER THE SECURITIES
ACT, (C) INSIDE THE UNITED STATES TO AN INSTITUTIONAL ACCREDITED INVESTOR THAT,
PRIOR TO SUCH TRANSFER, FURNISHES TO THE TRUSTEE A SIGNED LETTER CONTAINING
CERTAIN REPRESENTATIONS AND AGREEMENTS RELATING TO THE RESTRICTIONS ON TRANSFER
OF THE NOTE EVIDENCED HEREBY AND SUCH COMMON STOCK (THE FORM OF WHICH LETTER CAN
BE OBTAINED FROM THE TRUSTEE), (D) OUTSIDE THE UNITED STATES IN COMPLIANCE WITH
RULE 904 UNDER THE SECURITIES ACT OR (E) PURSUANT TO THE EXEMPTION FROM
REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE) AND
(3) AGREES THAT IT WILL DELIVER TO EACH PERSON TO WHOM THE NOTE EVIDENCED HEREBY
IS TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. IN
CONNECTION WITH ANY TRANSFER OF THE NOTE EVIDENCED HEREBY WITHIN THE TIME PERIOD
REFERRED TO IN RULE 144(k), THE HOLDER MUST CHECK THE APPROPRIATE BOX SET FORTH
ON THE REVERSE HEREOF RELATING TO THE MANNER OF SUCH TRANSFER AND SUBMIT THIS
CERTIFICATE TO THE TRUSTEE. IF THE PROPOSED TRANSFEREE IS AN INSTITUTIONAL
ACCREDITED INVESTOR, THE HOLDER MUST, PRIOR TO SUCH TRANSFER, FURNISH TO THE
TRUSTEE OR THE COMPANY, SUCH CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION
AS EITHER OF THEM MAY REASONABLY REQUIRE TO CONFIRM THAT SUCH TRANSFER IS BEING
MADE PURSUANT TO AN EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE
REGISTRATION REQUIREMENTS OF THE SECURITIES ACT. AS USED HEREIN, THE TERMS
"OFFSHORE TRANSACTION," "UNITED STATES" AND "U.S. PERSON" HAVE THE MEANINGS
GIVEN TO THEM BY REGULATION S UNDER THE SECURITY ACT.

                                       17
<PAGE>   25

                     ALLIED RISER COMMUNICATIONS CORPORATION

                  7.50% CONVERTIBLE SUBORDINATED NOTE DUE 2007

No. 01                                                       CUSIP NO. 019496AA6

                                                                 $150,000,000

          ALLIED RISER COMMUNICATIONS CORPORATION, a corporation duly organized
and existing under the laws of the State of Delaware (herein called the
"Company", which term includes any successor Person under the Indenture referred
to on the reverse hereof), for value received, hereby promises to pay to Cede &
Co., or registered assigns, the principal sum of One Hundred and Fifty Million
United States Dollars (U.S.$150,000,000) on June 15, 2007 and to pay interest
thereon, from June 28, 2000, or from the most recent Interest Payment Date (as
defined below) to which interest has been paid or duly provided for,
semi-annually in arrears on June 15 and December 15 in each year (each, an
"Interest Payment Date"), commencing December 15, 2000, at the rate of 7.50% per
annum, until the principal hereof is due, and at the rate of 7.50% per annum on
any overdue principal and premium, if any, and, to the extent permitted by law,
on any overdue interest. The interest so payable, and punctually paid or duly
provided for, on any Interest Payment Date will, as provided in the 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 June 1 or December 1 (whether or not a
Business Day), as the case may be, next preceding such Interest Payment Date.
Except as otherwise provided in the Indenture, 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 Company, notice whereof shall be given to Holders of
Securities not less than 10 days prior to the Special Record Date, or be paid at
any time in any other lawful manner not inconsistent with the requirements of
any automated quotation system or securities exchange on which the Securities
may be quoted or listed, and upon such notice as may be required by such
exchange, all as more fully provided in the Indenture. Payments of principal
shall be made upon the surrender of this Security at the option of the Holder at
the Corporate Trust Office of the Trustee, or at such other office or agency of
the Company as may be designated by it for such purpose in the Borough of
Manhattan, The City of New York, in such lawful monies of the United States of
America as at the time of payment shall be legal tender for the payment of
public and private debts, or at such other offices or agencies as the Company
may designate, by United States Dollar check drawn on, or wire transfer to, a
United States Dollar account (such a transfer to be made only to a Holder of an
aggregate principal amount of Securities in excess of U.S.$2,000,000 and only if
such Holder shall have furnished wire instructions in writing to the Trustee no
later than 15 days prior to the relevant payment date). Payment of interest on
this Security may be made by United States Dollar check

                                       18
<PAGE>   26

mailed to the address of the Person entitled thereto as such address shall
appear in the Security Register, or, upon written application by the Holder to
the Security Registrar setting forth wire instructions not later than the
relevant Record Date, by transfer to a United States Dollar account (such a
transfer to be made only to a Holder of an aggregate principal amount of
Securities in excess of U.S. $2,000,000 and only if such Holder shall have
furnished wire instructions in writing to the Trustee no later than 15 days
prior to the relevant payment date).

          The Company may, at its option, pay interest on the Securities in
Common Stock that has been registered under the Securities Act. If the Company
elects to pay interest in shares of Common Stock, the number of shares of Common
Stock to be distributed will be calculated by dividing the amount of such
interest otherwise payable in cash by 95% of the average of the Closing Price
Per Share for the five consecutive Trading Days immediately preceding the
Interest Payment Date. If the Company elects to pay any interest in Common
Stock, the Company will give the DTC 15 business days notice prior to the
related interest payment date and the DTC will forward such notice to Holders.

          If a shelf registration statement under the Securities Act with
respect to resales of the Securities and the shares of Common Stock, issuable
upon conversion of the Securities is not declared effective by the Commission on
or before December 28, 2000 in accordance with the terms of the Registration
Rights Agreement dated June 22, 2000 between the Company and Goldman, Sachs &
Co., the Company will pay, subject to the terms of the Registration Rights
Agreement, liquidated damages, in respect of the Securities, at a rate per annum
equal to (a) 0.25% of the principal amount per annum to and including the 90th
day after December 28, 2000 and (b) 0.50% of the principal amount per annum from
and after the 91st day after December 28, 2000.

          Except as specifically provided herein and in the Indenture, the
Company shall not be required to make any payment with respect to any tax,
assessment or other governmental charge imposed by any government or any
political subdivision or taxing authority thereof or therein.

          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 or an Authenticating Agent by the
manual signature of one of their respective authorized signatories, this
Security shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.

                                       19
<PAGE>   27

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

                                        ALLIED RISER COMMUNICATIONS
                                        CORPORATION

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

Attest:

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

TRUSTEE'S CERTIFICATE OF AUTHENTICATION

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

Dated:

WILMINGTON TRUST COMPANY,
as Trustee

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

                                       20
<PAGE>   28

                                [FORM OF REVERSE]

          This Security is one of a duly authorized issue of securities of the
Company designated as its " 7.50% Convertible Subordinated Notes due 2007"
(herein called the "Securities"), limited in aggregate principal amount to U.S.
$150,000,000 or if the Over-allotment Option is exercised in full, up to U.S.
$200,000,000 issued and to be issued under an Indenture, dated as of June 28,
2000 (herein called the "Indenture"), between the Company and Wilmington Trust
Company, as Trustee (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 Debt and the Holders of the Securities and of
the terms upon which the Securities are, and are to be, authenticated and
delivered. As provided in the Indenture and subject to certain limitations
therein set forth, Securities are exchangeable for a like aggregate principal
amount of Securities of any authorized denominations as requested by the Holder
surrendering the same upon surrender of the Security or Securities to be
exchanged, at the Corporate Trust Office of the Trustee. The Trustee upon such
surrender by the Holder will issue the new Securities in the requested
denominations.

          No sinking fund is provided for the Securities. The Securities will
not be subject to redemption until on or after the third Business Day after June
15, 2004 and will be redeemable on and after that date at the option of the
Company, in whole or in part, upon not less than 30 nor more than 60 days notice
to the Holders prior to the Redemption Date at the Redemption Prices (expressed
as percentages of the principal amount) set forth below.

          The following table sets forth the Redemption Prices (expressed as
percentages of the principal amount) if such Security is redeemed during the
12-month period beginning June 15 (beginning the third Business Day after June
15, 2004 through June 14, 2005 in the case of the first such period):

<TABLE>
<CAPTION>
                  YEAR                                REDEMPTION PRICE
                  ----                                ----------------
<S>                                                   <C>
                  2004                                    103.214%
                  2005                                    102.143%
                  2006                                    101.071%
                  2007                                    100.000%
</TABLE>

and thereafter at a Redemption Price equal to 100% of the principal amount,
together, in each case, with accrued interest to the Redemption Date; provided,
however, that interest installments on Securities whose Stated Maturity is on or
prior to such Redemption Date will be payable to the Holders of such Securities,
or one or more Predecessor Securities, of record at the close of business on the
relevant Record Dates referred to on the face hereof, all as provided in the
Indenture.

          In the event of a redemption of the Securities, the Company will not
be required (a) to register the transfer or exchange of Securities for a period
of 15 days immediately preceding the date notice is given identifying the serial
numbers of the Securities called for such redemption or (b) to register the
transfer or exchange of any Security, or portion thereof, called for redemption.

                                       21
<PAGE>   29

          In any case where the due date for the payment of the principal of,
premium, if any, or interest on, any Security or the last day on which a Holder
of a Security has a right to convert his Security shall be, at any Place of
Payment or Place of Conversion as the case may be, a day on which banking
institutions at such Place of Payment or Place of Conversion are authorized or
obligated by law or executive order to close, then payment of principal,
premium, if any, interest, or delivery for conversion of such Security need not
be made on or by such date at such place but may be made on or by the next
succeeding day at such place which is not a day on which banking institutions
are authorized or obligated by law or executive order to close, with the same
force and effect as if made on the date for such payment or the date fixed for
redemption or repurchase, or by such last day for conversion, and no interest
shall accrue on the amount so payable for the period after such date.

          Subject to and upon compliance with the provisions of the Indenture,
the Holder of this Security is entitled, at his option, at any time on or before
the close of business on the date of Maturity, or in case this Security or a
portion hereof is called for redemption or the Holder hereof has exercised his
right to require the Company to repurchase this Security or such portion hereof,
then in respect of this Security until the Business Day immediately preceding,
but (unless the Company defaults in making the payment due upon redemption or
repurchase, as the case may be) not after, the close of business on the Business
Day immediately preceding the Redemption Date or the Repurchase Date, as the
case may be, to convert this Security (or any portion of the principal amount
hereof that is an integral multiple of U.S.$1,000, provided that the unconverted
portion of such principal amount is U.S.$1,000 or any integral multiple of
U.S.$1,000 in excess thereof) into fully paid and nonassessable shares of Common
Stock of the Company at an initial Conversion Rate of 65.0618 shares of Common
Stock for each U.S.$1,000 principal amount of Securities (or at the current
adjusted Conversion Rate if an adjustment has been made as provided in the
Indenture) by surrender of this Security, duly endorsed or assigned to the
Company or in blank and, in case such surrender shall be made during the period
from the close of business on any Regular Record Date next preceding any
Interest Payment Date to the opening of business on such Interest Payment Date
(except if this Security or portion thereof has been called for redemption on a
Redemption Date or is repurchasable on a Repurchase Date occurring, in either
case, during such period and, as a result, the right to convert this Security
would otherwise terminate in such period if not exercised), also accompanied by
payment in New York Clearing House or other 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, and also the conversion
notice hereon duly executed, to the Company at the Corporate Trust Office of the
Trustee, or at such other office or agency of the Company, subject to any laws
or regulations applicable thereto and subject to the right of the Company to
terminate the appointment of any Conversion Agent (as defined below) as may be
designated by it for such purpose in the Borough of Manhattan, The City of New
York, or at such other offices or agencies as the Company may designate (each a
"Conversion Agent"), provided, further, that if this Security or portion hereof
has been called for redemption on a Redemption Date or is repurchasable on a
Repurchase Date occurring, in either case, during the period from the close of
business on any Regular Record Date next preceding any Interest Payment Date to
the opening of business on such succeeding Interest Payment Date, and as a
result, the right to convert this

                                       22
<PAGE>   30

Security would otherwise terminate in such period if not exercised and this
Security is surrendered for conversion during such period, then the Holder of
this Security on such Regular Record Date will be entitled to receive the
interest accruing hereon from the Interest Payment Date next preceding the date
of such conversion to such succeeding Interest Payment Date and the Holder of
this Security who converts this Security or a portion hereof during such period
shall not be required to pay such interest upon surrender of this Security for
conversion. Subject to the provisions of the preceding sentence and, in the case
of a conversion after the close of business on the Regular Record Date next
preceding any Interest Payment Date and on or before the close of business on
such Interest Payment Date, to the right of the Holder of this Security (or any
Predecessor Security) of record as of such Regular Record Date to receive the
related installment of interest to the extent and under the circumstances
provided in the Indenture, no cash payment or adjustment is to be made on
conversion for interest accrued hereon from the Interest Payment Date next
preceding the day of conversion, or for dividends on the Common Stock issued on
conversion hereof. The Company shall thereafter deliver to the Holder the fixed
number of shares of Common Stock (together with any cash adjustment, as provided
in the Indenture) into which this Security is convertible and such delivery will
be deemed to satisfy the Company's obligation to pay the principal amount of
this Security. No fractions of shares or scrip representing fractions of shares
will be issued on conversion, but instead of any fractional interest (calculated
to the nearest 1/100th of a share) the Company shall pay a cash adjustment as
provided in the Indenture. The Conversion Rate is subject to adjustment as
provided in the Indenture. In addition, the Indenture provides that in case of
certain consolidations or mergers to which the Company is a party (other than a
consolidation or merger that does not result in any reclassification,
conversion, exchange or cancellation of the Common Stock) or the conveyance,
transfer, sale or lease of all or substantially all of the property and assets
of the Company, 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 such consolidation, merger, conveyance, transfer, sale
or lease by a holder of the number of shares of Common Stock of the Company into
which this Security could have been converted immediately prior to such
consolidation, merger, conveyance, transfer, sale or lease (assuming such holder
of Common Stock is not a Constituent Person or an Affiliate of a Constituent
Person, 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. No
adjustment in the Conversion Rate will be made until such adjustment would
require an increase or decrease of at least one percent of such rate, provided
that any adjustment that would otherwise be made will be carried forward and
taken into account in the computation of any subsequent adjustment.

          If a Change in Control occurs, the Holder of this Security, at the
Holder's option, shall have the right, in accordance with the provisions of the
Indenture, to require the Company to repurchase this Security (or any portion of
the principal amount hereof that is at least $1,000 or an integral multiple of
$1,000 in excess thereof, provided that the portion of the principal amount of
this Security to be Outstanding after such repurchase is at least equal to
U.S.$1,000) for cash at a Repurchase Price equal to 100% of the principal amount
thereof plus interest accrued to the Repurchase 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 that have been
registered under the Securities Act having a fair market value equal to the
Repurchase Price. For purposes of this paragraph, the fair market value of
shares of

                                       23
<PAGE>   31

Common Stock shall be determined by the Company and shall be equal to 95% of the
average of the Closing Prices Per Share for the 20 consecutive Trading Days
immediately preceding and including the third Trading Day prior to the
Repurchase Date. Whenever in this Security 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
Security shall not be construed as excluding the Repurchase Price so payable in
those provisions of this Security when such express mention is not made;
provided, however, that, for the purposes of the second succeeding paragraph,
such reference shall be deemed to include reference to the Repurchase Price only
to the extent the Repurchase Price is payable in cash.

          [THE FOLLOWING PARAGRAPH SHALL APPEAR IN EACH GLOBAL SECURITY:

          In the event of a deposit or withdrawal of any interest in this
Security, including an exchange, transfer, redemption, repurchase or conversion
of this Security in part only, the Trustee, as custodian of the Depositary,
shall make an adjustment on its records to reflect such deposit or withdrawal in
accordance with the Applicable Procedures.]

          [THE FOLLOWING PARAGRAPH SHALL APPEAR IN EACH SECURITY THAT IS NOT A
GLOBAL SECURITY:

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

          The indebtedness evidenced by this Security is, to the extent and in
the manner provided in the Indenture, subordinate and subject in right of
payment to the prior payment in full of all Senior Debt of the Company, and this
Security is issued subject to such 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, together with accrued interest to the date of declaration,
may be declared due and payable in the manner and with the effect provided in
the Indenture. Upon payment (i) of the amount of principal so declared due and
payable, together with accrued interest to the date of declaration, and (ii) of
interest on any overdue principal and, to the extent permitted by applicable
law, overdue interest, all of the Company's obligations in respect of the
payment of the principal of and interest on the Securities shall terminate.

          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 either (a) the written consent of
the Holders of not less than a majority in principal

                                       24
<PAGE>   32

amount of the Securities at the time Outstanding, or (b) by the adoption of a
resolution, at a meeting of Holders of the Outstanding Securities at which a
quorum is present, by the Holders of at least 66*% in aggregate principal amount
of the Outstanding Securities represented and entitled to vote at such meeting.
The Indenture also contains provisions permitting the Holders of specified
percentages in 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 in exchange therefore
or in lieu hereof whether or not notation of such consent or waiver is made upon
this Security or such other Security.

          As provided in and subject to the provisions of the Indenture, the
Holder of this Security shall not have the right to institute any proceeding
with respect to the Indenture or for the appointment of a receiver or trustee or
for any other remedy thereunder, unless such Holder shall have previously given
the Trustee written notice of a continuing Event of Default, 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 as Trustee and offered the Trustee reasonable indemnity and the
Trustee shall not have received from the Holders of a majority in principal
amount of the Securities Outstanding a direction inconsistent with such request,
and shall have failed to institute any such proceeding, for 60 days after
receipt of such notice, request and offer of indemnity. The foregoing shall not
apply to any suit instituted by the Holder of this Security for the enforcement
of any payment of principal hereof, premiums if any, or interest hereon on or
after the respective due dates expressed herein or for the enforcement of the
right to convert this Security as provided in the Indenture.

          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, places 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 on the Security
Register upon surrender of this Security for registration of transfer at the
Corporate Trust Office of the Trustee or at such other office or agency of the
Company as may be designated by it for such purpose in the Borough of Manhattan,
The City of New York (which shall initially be an office or agency of the
Trustee), or at such other offices or agencies as the Company may designate,
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 thereof 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 by
the Security Registrar. 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 recover any tax or other governmental charge payable in
connection therewith.

                                       25
<PAGE>   33

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

          No recourse for the payment of the principal (and premium, if any) or
interest on this Security and no recourse under or upon any obligation, covenant
or agreement of the Company in the Indenture or any indenture supplemental
thereto or in any Security, or because of the creation of any indebtedness
represented thereby, shall be had against any incorporator, stockholder,
employee, agent, officer or director or subsidiary, as such, past, present or
future, of the Company or of any successor corporation, either directly or
through the Company or 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, by the acceptance hereof and as
part of consideration for the issue hereof, expressly waived and released.

          THE INDENTURE AND THIS SECURITY SHALL BE GOVERNED BY THE LAWS OF THE
STATE OF NEW YORK.

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

                                  ABBREVIATIONS

          The following abbreviations, when used in the inscription of the face
of this Security, shall be construed as though they were written out in full
according to applicable laws or regulations:

TEN COM -- as tenant in common
TEN ENT -- as tenants by the entireties (Cust)
JT TEN  -- as joint tenants with right
           of survivorship and not as
           tenants in common

UNIF GIFT MIN ACT--
______________ Custodian
(cust)

______________ under
(Minor)

Uniform Gifts to Minors Act
_____________________ (State)

     Additional abbreviations may also be used though not in the above list.

                                       26
<PAGE>   34

                            [FORM OF TRANSFER NOTICE]

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

Insert Taxpayer Identification No.

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

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

                     [THE FOLLOWING PROVISION TO BE INCLUDED
                             ON ALL NOTES OTHER THAN
                    UNLEGENDED OFFSHORE GLOBAL SECURITIES AND
                    UNLEGENDED OFFSHORE PHYSICAL SECURITIES]

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

                                   [Check One]

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

or

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

                                       27
<PAGE>   35

          If none of the foregoing boxes is checked, the Trustee or other
Security Registrar shall not be obligated to register this Security in the name
of any Person other than the Holder hereof unless and until the conditions to
any such transfer of registration set forth herein and in Section 3.7 of the
Indenture shall have been satisfied.

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

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

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

Dated:
     -------------------          ----------------------------------------------
                                  NOTICE: To be executed by an executive officer

                                       28
<PAGE>   36

                    ELECTION OF HOLDER TO REQUIRE REPURCHASE

          (1) Pursuant to Section 14.1 of the Indenture, the undersigned hereby
elects to have this Security repurchased by the Company.

          (2) The undersigned hereby directs the Trustee or the Company to pay
it or ______________ an amount in cash or, at the Company's election, Common
Stock that has been registered under the Securities Act valued as set forth in
the Indenture, equal to 100% of the principal amount to be repurchased (as set
forth below), plus interest accrued to the Repurchase Date, as provided in the
Indenture.

Dated:
      -----------------------

      -----------------------
      Signature(s)

Signature(s) must be guaranteed by an Eligible Guarantor Institution with
membership in an approved signature guarantee program pursuant to Rule 17Ad-15
under the Securities Exchange Act of 1934.

-----------------------
Signature Guaranteed

Principal amount to be repurchased (at least U.S. $1,000 or an integral multiple
of $1,000 in excess thereof): ______________

Remaining principal amount following such repurchase (not less than U.S.
$1,000):

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

          NOTICE: The signature to the foregoing Election must correspond to the
Name as written upon the face of this Security in every particular, without
alteration or any change whatsoever.

          SECTION 2.3 FORM OF CERTIFICATE OF AUTHENTICATION. The Trustee's
certificate of authentication shall be in substantially the following form:

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

Dated:
      -----------------------

                  WILMINGTON TRUST COMPANY
                   as Trustee

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

                                       29
<PAGE>   37

          SECTION 2.4 FORM OF CONVERSION NOTICE.

                                CONVERSION NOTICE

          The undersigned Holder of this Security hereby irrevocably exercises
the option to convert this Security, or any portion of the principal amount
hereof (which is U.S. $1,000 or an integral multiple of U.S. $1,000 in excess
thereof, provided that the unconverted portion of such principal amount is U.S.
$1,000 or any integral multiple of U.S. $1,000 in excess thereof) below
designated, into shares of Common Stock in accordance with the terms of the
Indenture referred to in this Security, and directs that such shares, together
with a check in payment for any fractional share and any Securities representing
any unconverted principal amount hereof, be delivered to and be registered in
the name of the undersigned unless a different name has been indicated below. If
shares of Common Stock or Securities are to be registered in the name of a
Person other than the undersigned, (a) the undersigned will pay all transfer
taxes payable with respect thereto and (b) signature(s) must be guaranteed by an
Eligible Guarantor Institution with membership in an approved signature
guarantee program pursuant to Rule 17Ad-15 under the Securities Exchange Act of
1934. Any amount required to be paid by the undersigned on account of interest
accompanies this Security.

Dated:

-------------              ---------------------------
                                   Signature(s)

If shares or Securities are to be registered in the name of a Person other than
the Holder, please print such Person's name and address:

--------------------------
(Name)

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

--------------------------
(Address)

--------------------------
Social Security or other Identification
Number, if any

--------------------------
[Signature Guaranteed]

If only a portion of the Securities is to be converted, please indicate:

1.   Principal amount to be converted: U.S. $ ___________

                                       30
<PAGE>   38

2.   Principal amount and denomination of Securities representing unconverted
principal amount to be issued:

     Amount: U.S. $___________ Denominations: U.S. $____________

(U.S. $1,000 or any integral multiple of U.S. $1,000 in excess thereof, provided
that the unconverted portion of such principal amount is U.S. $1,000 or any
integral multiple of U.S. $1,000 in excess thereof)

          SECTION 2.5 FORM OF ASSIGNMENT.

          For value received ________________ hereby sell(s), assign(s) and
transfer(s) unto ________________ (Please insert social security or other
identifying number of assignee) the within Security, and hereby irrevocably
constitutes and appoints ____________________as attorney to transfer the said
Security on the books of the Company, with full power of substitution in the
premises.

Dated:

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

                           ------------------------------
                           Signature(s)

                           Signature(s) must be guaranteed by an Eligible
                           Guarantor Institution with membership in an approved
                           signature guarantee program pursuant to Rule 17Ad-15
                           under the Securities Exchange Act of 1934.

                           ------------------------------
                           Signature Guaranteed

                                       31
<PAGE>   39

                                  ARTICLE III

                                 THE SECURITIES

          SECTION 3.1 TITLE AND TERMS. The aggregate principal amount of
Securities which may be authenticated and delivered under this Indenture is
limited to U.S. $150,000,000 (or U.S.$200,000,000 if the Over-allotment Option
set forth in Section 2 of the Purchase Agreement is exercised in full (the
"Over-allotment Option")), except for Securities authenticated and delivered
pursuant to Section 3.5, 3.6, 3.8, 8.5, 12.2 or 14.3(5) in exchange for, or in
lieu of, other Securities previously authenticated and delivered under this
Indenture.

          The Securities shall be known and designated as the "7.50% Convertible
Subordinated Notes due 2007" of the Company. Their Stated Maturity shall be June
15, 2007 and they shall bear interest on their principal amount from June 28,
2000, payable semi-annually in arrears on June 15 and December 15 in each year,
commencing December 15, 2000, at the rate of 7.50 % per annum until the
principal thereof is due and at the rate of 7.50% per annum on any overdue
principal and, to the extent permitted by law, on any overdue interest;
provided, however, that payments shall only be made on a Business Day as
provided in Section 1.12.

          The principal of, premium, if any, and interest on the Securities
shall be payable as provided in the form of Securities set forth in Section 2.2,
and the Repurchase Price, whether payable in cash or in shares of Common Stock
that have been registered under the Securities Act, shall be payable at such
places as are identified in the Company Notice given pursuant to Section 14.3
(any city in which any Paying Agent is located being herein called a "Place of
Payment").

          The Securities shall be redeemable at the option of the Company at any
time on or after the third Business Day after June 15, 2004, in whole or in
part, subject to the conditions and as otherwise provided in Article XI and in
the form of Security set forth in Section 2.2.

          The Securities shall be convertible as provided in Article XII (any
city in which any Conversion Agent is located being herein called a "Place of
Conversion").

          The Securities shall be subordinated in right of payment to Senior
Debt of the Company as provided in Article XIII.

          The Securities shall be subject to repurchase by the Company at the
option of the Holders as provided in Article XIV.

          SECTION 3.2 DENOMINATIONS. The Securities shall be issuable only in
registered form, without coupons, in denominations of U.S. $1,000 and integral
multiples of U.S. $1,000 in excess thereof.

                                       32
<PAGE>   40

          SECTION 3.3 EXECUTION, AUTHENTICATION, DELIVERY AND DATING. The
Securities shall be executed on behalf of the Company by its Chairman of the
Board, its Vice Chairman of the Board, its Chief Executive Officer, its
President, one of its Executive Vice Presidents or one of its Vice Presidents,
and attested by its Chief Financial Officer, Secretary or one of its Assistant
Secretaries. Any such signature may be manual or facsimile.

          Securities bearing the manual or facsimile signature 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 or to its order for authentication, together with a Company Order
for the authentication and delivery of such Securities, and the Trustee in
accordance with such Company Order shall authenticate and make available for
delivery such Securities as in this Indenture provided.

          Each Security shall be dated the date of its authentication.

          No Security shall be entitled to any benefit under this Indenture or
be valid or obligatory for any purpose unless there appears on such Security a
certificate of authentication substantially in the form provided for herein
executed by the Trustee by manual signature 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.

          SECTION 3.4 RESTRICTIVE LEGENDS. (a) (i) The U.S. Global Security and
each U.S. Physical Security shall bear the legend set forth below on the face
thereof until the expiration of the time period referred to in Rule 144(k) under
the Securities Act, as in effect from time to time, with respect to such
Security, unless such Security has been sold pursuant to an effective Shelf
Registration Statement, and (ii) the Offshore Physical Securities shall bear the
legend set forth below on the face thereof until at least 41 days after the
Closing Date and receipt by the Company and the Trustee of a certificate
substantially in the form of Exhibit A hereto:

     THIS NOTE AND ANY COMMON STOCK ISSUABLE UPON THE CONVERSION OF THIS NOTE
     HAVE NOT BEEN AND WILL NOT BE REGISTERED UNDER THE U.S. SECURITIES ACT OF
     1933, AS AMENDED (THE "SECURITIES ACT"), AND ACCORDINGLY, MAY NOT BE
     OFFERED OR SOLD WITHIN THE UNITED STATES OR TO, OR FOR THE ACCOUNT OR
     BENEFIT OF, U.S. PERSONS EXCEPT AS SET FORTH IN THE FOLLOWING SENTENCE. BY
     ITS ACQUISITION HEREOF, THE HOLDER (1) REPRESENTS THAT (A) IT IS A
     "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE
     SECURITIES ACT) OR (B) (C) IT IS NOT A U.S. PERSON AND IS ACQUIRING THE
     NOTE EVIDENCED HEREBY IN AN OFFSHORE TRANSACTION, (2) AGREES THAT IT WILL
     NOT RESELL OR OTHERWISE TRANSFER THE NOTE EVIDENCED HEREBY OR THE COMMON
     STOCK ISSUABLE UPON CONVERSION OF SUCH NOTE

                                       33
<PAGE>   41

     WITHIN THE TIME PERIOD REFERRED TO UNDER RULE 144(k) (TAKING INTO ACCOUNT
     THE PROVISIONS OF RULE 144(d) IN THE CASE OF SUCH STOCK) EXCEPT (A) TO THE
     COMPANY OR ANY SUBSIDIARY THEREOF, (B) INSIDE THE UNITED STATES TO A
     QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A UNDER THE
     SECURITIES ACT, (C) INSIDE THE UNITED STATES TO AN INSTITUTIONAL ACCREDITED
     INVESTOR THAT, PRIOR TO SUCH TRANSFER, FURNISHES TO THE TRUSTEE A SIGNED
     LETTER CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS RELATING TO THE
     RESTRICTIONS ON TRANSFER OF THE NOTE EVIDENCED HEREBY AND SUCH COMMON STOCK
     (THE FORM OF WHICH LETTER CAN BE OBTAINED FROM THE TRUSTEE), (D) OUTSIDE
     THE UNITED STATES IN COMPLIANCE WITH RULE 904 UNDER THE SECURITIES ACT OR
     (E) PURSUANT TO THE EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER
     THE SECURITIES ACT (IF AVAILABLE) AND (3) AGREES THAT IT WILL DELIVER TO
     EACH PERSON TO WHOM THE NOTE EVIDENCED HEREBY IS TRANSFERRED A NOTICE
     SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND. IN CONNECTION WITH ANY TRANSFER
     OF THE NOTE EVIDENCED HEREBY WITHIN THE TIME PERIOD REFERRED TO IN RULE
     144(k), THE HOLDER MUST CHECK THE APPROPRIATE BOX SET FORTH ON THE REVERSE
     HEREOF RELATING TO THE MANNER OF SUCH TRANSFER AND SUBMIT THIS CERTIFICATE
     TO THE TRUSTEE. IF THE PROPOSED TRANSFEREE IS AN INSTITUTIONAL ACCREDITED
     INVESTOR, THE HOLDER MUST, PRIOR TO SUCH TRANSFER, FURNISH TO THE TRUSTEE
     OR THE COMPANY, SUCH CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS
     EITHER OF THEM MAY REASONABLY REQUIRE TO CONFIRM THAT SUCH TRANSFER IS
     BEING MADE PURSUANT TO AN EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT
     TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT. THIS LEGEND WILL
     BE REMOVED AFTER THE EXPIRATION OF SUCH TIME PERIOD. AS USED HEREIN, THE
     TERMS "OFFSHORE TRANSACTION," "UNITED STATES" AND "U.S. PERSON" HAVE THE
     MEANINGS GIVEN TO THEM BY REGULATION S UNDER THE SECURITIES ACT.

          (b) Unless a Conversion Share has been sold pursuant to a Shelf
Registration statement, each stock certificate representing any Conversion Share
shall bear the legend set forth below:

     THE COMMON STOCK EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER THE U.S.
     SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE
     SECURITIES LAWS, AND ACCORDINGLY, MAY NOT BE OFFERED OR SOLD WITHIN THE
     UNITED STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT OF, U.S. PERSONS EXCEPT
     AS SET FORTH IN THE FOLLOWING SENTENCE. THE HOLDER HEREOF AGREES THAT UNTIL
     THE EXPIRATION OF THE

                                       34
<PAGE>   42

     TIME PERIOD REFERRED TO IN RULE 144(k) (1) IT WILL NOT RESELL OR OTHERWISE
     TRANSFER THE COMMON STOCK EVIDENCED HEREBY EXCEPT (A) TO THE COMPANY OR ANY
     SUBSIDIARY THEREOF, (B) INSIDE THE UNITED STATES TO A "QUALIFIED
     INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) IN
     COMPLIANCE WITH RULE 144A, (C) INSIDE THE UNITED STATES TO AN INSTITUTIONAL
     "ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(A)(1), (2), (3) OR (7) UNDER
     THE SECURITIES ACT) THAT, PRIOR TO SUCH TRANSFER, FURNISHES TO THE TRANSFER
     AGENT A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS
     RELATING TO THE RESTRICTIONS ON TRANSFER OF THE COMMON STOCK EVIDENCED
     HEREBY (THE FORM OF WHICH LETTER CAN BE OBTAINED FROM THE TRANSFER AGENT),
     (D) OUTSIDE THE UNITED STATES IN COMPLIANCE WITH RULE 904 UNDER THE
     SECURITIES ACT, (E) PURSUANT TO THE EXEMPTION FROM REGISTRATION PROVIDED BY
     RULE 144 UNDER THE SECURITIES ACT (IF AVAILABLE), OR (F) PURSUANT TO A
     REGISTRATION STATEMENT WHICH HAS BEEN DECLARED EFFECTIVE UNDER THE
     SECURITIES ACT (AND WHICH CONTINUES TO BE EFFECTIVE AT THE TIME OF SUCH
     TRANSFER); (2) PRIOR TO SUCH TRANSFER (OTHER THAN A TRANSFER PURSUANT TO
     CLAUSE (F) ABOVE), IT WILL FURNISH TO THE TRANSFER AGENT SUCH
     CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS IT MAY REASONABLY
     REQUIRE TO CONFIRM THAT SUCH TRANSFER IS BEING MADE PURSUANT TO AN
     EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION
     REQUIREMENTS OF THE SECURITIES ACT AND (3) IT WILL DELIVER TO EACH PERSON
     TO WHOM THE COMMON STOCK EVIDENCED HEREBY IS TRANSFERRED (OTHER THAN A
     TRANSFER PURSUANT TO CLAUSE (F) ABOVE) A NOTICE SUBSTANTIALLY TO THE EFFECT
     OF THIS LEGEND. THIS LEGEND WILL BE REMOVED UPON THE EARLIER OF THE
     TRANSFER OF THE COMMON STOCK EVIDENCED HEREBY PURSUANT TO CLAUSE (F) ABOVE)
     OR THE EXPIRATION OF THE TIME PERIOD REFERRED TO ABOVE OR UPON THE EARLIER
     SATISFACTION OF EXIDE CORPORATION AND THE TRANSFER AGENT THAT THE COMMON
     STOCK HAS BEEN OR IS BEING OFFERED AND SOLD IN COMPLIANCE WITH RULE 904
     UNDER THE SECURITIES ACT. AS USED HEREIN, THE TERMS "UNITED STATES" AND
     "U.S. PERSON" HAVE THE MEANINGS GIVEN TO THEM BY REGULATION S UNDER THE
     SECURITIES ACT.

          (c) Each Global Security shall also bear the following legend on the
face thereof:

     UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
     DEPOSITORY TRUST COMPANY TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF
     TRANSFER, EXCHANGE OR PAYMENT, AND ANY NOTE ISSUED IS REGISTERED IN

                                       35
<PAGE>   43

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

     TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS IN WHOLE,
     BUT NOT IN PART, TO NOMINEES OF CEDE & CO. OR TO A SUCCESSOR THEREOF OR
     SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL SECURITY
     SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET
     FORTH IN SECTION 3.7 OF THE INDENTURE.

          SECTION 3.5 REGISTRATION; REGISTRATION OF TRANSFER AND EXCHANGE;
RESTRICTIONS ON TRANSFER. The Company shall cause to be kept at the Corporate
Trust Office of the Trustee a register (the register maintained in such office
referred to as the "Security Register") in which, subject to such reasonable
regulations as it may prescribe, the Company shall provide for the registration
of Securities and of transfers of Securities. The Trustee is hereby appointed
"Security Registrar" for the purpose of registering Securities and transfers and
exchanges of Securities as herein provided.

          Upon surrender for registration of transfer of any Security at an
office or agency of the Company designated pursuant to Section 10.2 for such
purpose, the Company shall execute, and the Trustee shall authenticate and
deliver, in the name of the designated transferee or transferees, one or more
new Securities of any authorized denominations and of a like aggregate principal
amount.

          At the option of the Holder, and subject to the other provisions of
this Section 3.5, Securities may be exchanged for other Securities of any
authorized denomination and of a like aggregate principal amount, upon surrender
of the Securities to be exchanged at any such office or agency. Whenever any
Securities are so surrendered for exchange, and subject to the other provisions
of this Section 3.5, the Company shall execute, and the Trustee shall
authenticate and deliver, the Securities which the Holder making the exchange is
entitled to receive. Every Security presented or surrendered for registration of
transfer or for exchange 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, the Trustee and the Security
Registrar duly executed, by the Holder thereof or his attorney duly authorized
in writing.

                                       36
<PAGE>   44
          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.

          No service charge shall be made to a Holder for any registration of
transfer or exchange of Securities except as provided in Section 3.8, 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
3.6, 8.5, 12.2 or 14.3 (other than where the shares of Common Stock are to be
issued or delivered in a name other than that of the Holder of the Security) not
involving any transfer and other than any stamp and other duties, if any, which
may be imposed in connection with any such transfer or exchange by the United
States or any political subdivision thereof or therein, which shall be paid by
the Company.

          In the event of a redemption of the Securities, neither the Company
nor the Securities Registrar will be required (a) to register the transfer of or
exchange Securities for a period of 15 days immediately preceding the date
notice is given identifying the serial numbers of the Securities called for such
redemption or (b) to register the transfer of or exchange any Security, or
portion thereof, called for redemption.

          SECTION 3.6 BOOK-ENTRY PROVISIONS FOR GLOBAL SECURITIES. (a) The U.S.
Global Securities and Offshore Global Securities initially shall (i) be
registered in the name of the Depositary for such Global Securities or the
nominee of such Depositary, (ii) be delivered to the Trustee as custodian for
such Depositary and (iii) bear legends as set forth in Section 3.4.

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

          (b) Transfers of a Global Security shall be limited to transfers of
such Global Security in whole, but not in part, to the Depositary, its
successors or their respective nominees. Interests of beneficial owners in a
Global Security may be transferred in accordance with the applicable rules and
procedures of the Depositary and the provisions of Section 3.7. In addition,
U.S. Physical Securities and Offshore Physical Securities shall be transferred
to all beneficial owners in exchange for their beneficial interests in the U.S.
Global Security or the Offshore Global Security, respectively, if (i) the
Depositary notifies the Company that it is unwilling or unable to continue as
Depositary for the U.S. Global Securities or the Offshore Global Security, as
the case may be, and a successor depositary is not appointed by the Company
within 90 days of such notice, (ii) an Event of Default has occurred and is
continuing and the Security Registrar

                                       37
<PAGE>   45

has received a request to the foregoing effect from the Depositary, or (iii) in
accordance with the rules and procedures of the Depositary and the provisions of
Section 3.7.

          (c) Any beneficial interest in one of the Global Securities that is
transferred to a Person who takes delivery in the form of an interest in the
other Global Security will, upon transfer, cease to be an interest in such
Global Securities and become an interest in the other Global Security and,
accordingly, will thereafter be subject to all transfer restrictions, if any,
and other procedures applicable to beneficial interests in such other Global
Security for as long as it remains such an interest.

          (d) In connection with any transfer pursuant to paragraph (b) of this
Section 3.6 of a portion of the beneficial interests in the U.S. Global Security
to beneficial owners who are required to hold U.S. Physical Securities, the
Security Registrar shall reflect on its books and records the date and a
decrease in the principal amount at maturity of the U.S. Global Security in an
amount equal to the principal amount at maturity of the beneficial interest in
the U.S. Global Security to be transferred, and the Company shall execute, and
the Trustee shall authenticate and deliver, one or more U.S. Physical Securities
of like tenor and amount.

          (e) In connection with the transfer of the entire U.S. Global Security
or Offshore Global Security to beneficial owners pursuant to paragraph (b) of
this Section 3.6, the U.S. Global Security or Offshore Global Security, as the
case may be, shall be deemed to be surrendered to the Trustee for cancellation,
and the Company shall execute, and the Trustee shall authenticate and deliver,
to each beneficial owner identified by the Depositary in exchange for its
beneficial interest in the U.S. Global Security or Offshore Global Security, as
the case may be, an equal aggregate principal amount at maturity of U.S.
Physical Securities or Offshore Physical Securities, as the case may be, of
authorized denominations.

          (f) Any U.S. Physical Security delivered in exchange for an interest
in the U.S. Global Security pursuant to paragraph (b) or (d) of this Section 3.6
shall, except as otherwise provided by paragraph (f) of Section 3.7, bear the
legend regarding transfer restrictions applicable to the U.S. Physical Security
set forth in Section 3.4.

          (g) Any Offshore Physical Security delivered in exchange for an
interest in the Offshore Global Security pursuant to paragraph (b), (d) or (e)
of this Section 3.6 shall, except as otherwise provided by paragraph (f) of
Section 3.7, bear the legend regarding transfer restrictions applicable to the
Offshore Physical Security set forth in Section 3.4.

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

          SECTION 3.7 SPECIAL TRANSFER PROVISIONS. Unless and until a Security
is sold in connection with an effective Shelf Registration Statement, the
following provisions shall apply:

                                       38
<PAGE>   46

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

               (i) The Security Registrar shall register the transfer of any
          Security, whether or not such Security bears the Private Placement
          Legend, if (x) the requested transfer is after the time period
          referred to in Rule 144(k) under the Securities Act or (y) the
          proposed transferee has delivered to the Security Registrar (A) a
          certificate substantially in the form of Exhibit B hereto and (B) if
          the aggregate principal amount of the Securities being transferred is
          less than $100,000, an opinion of counsel acceptable to the Company
          that such transfer is in compliance with the Securities Act.

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

          (b) Transfers to QIBs. The following provisions shall apply with
respect to the registration of any proposed transfer of a Securities to a QIB
(excluding Non-U.S. Persons):

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

               (ii) If the proposed transferee is an Agent Member, and the
          Security to be transferred consists of either Offshore Physical
          Securities prior to removal of the Private Placement Legend or U.S.
          Physical Securities, upon receipt by the Security Registrar of the
          documents referred to in paragraph (i) above and instructions given in
          accordance

                                       39
<PAGE>   47

          with the Depositary's and the Security Registrar's procedures, the
          Security Registrar shall reflect on its books and records the date and
          an increase in the principal amount of U.S. Global Securities in an
          amount equal to the principal amount of the Offshore Physical Notes or
          U.S. Physical Securities to be transferred, and the Trustee shall
          cancel the Offshore Physical Securities or U.S. Physical Securities so
          transferred.

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

               (i)  prior to the removal of the Private Placement Legend from
                    the Offshore Global Securities or Offshore Physical
                    Securities pursuant to Section 3.4, the Security Registrar
                    shall refuse to register such transfer unless such transfer
                    complied with Section 3.7(b).

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

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

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

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

          (e) Private Placement Legend. Upon the transfer, exchange or
replacement of Securities not bearing the Private Placement Legend, the Security
Registrar shall deliver Securities that do not bear the Private Placement
Legend. Upon the transfer, exchange or replacement of Securities bearing the
Private Placement Legend, the Security Registrar shall deliver only Securities
that bear the Private Placement Security Legend unless (i) the Private Placement
Legend is no longer required by Section 3.4, (ii) the circumstances contemplated
by

                                       40
<PAGE>   48

paragraph (a)(i)(x) of this Section 3.7 exist or (iii) there is delivered to the
Security Registrar an Opinion of Counsel reasonably satisfactory to the Company
and the Trustee to the effect that neither such legend nor the related
restrictions on transfer are required in order to maintain compliance with the
provisions of the Securities Act.

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

          The Security Registrar shall retain copies of all letters, notices and
other written communications received pursuant to Section 3.6 or this Section
3.7. The Company shall have the right to inspect and make copies of all such
letters, notices or other written communications at any reasonable time upon the
giving of reasonable written notice to the Security Registrar.

          SECTION 3.8 MUTILATED, DESTROYED, LOST OR STOLEN SECURITIES. If any
mutilated Security is surrendered to the Trustee, the Company shall execute and
the Trustee shall authenticate and deliver in exchange therefor a new Security
of like tenor and principal amount and bearing a number not contemporaneously
outstanding.

          If there be delivered to the Company and to the Trustee:

          (1) evidence to their satisfaction of the destruction, loss or theft
     of any Security, and

          (2) such security or indemnity as may be satisfactory to the Company
     and the Trustee to save each of them and any agent of either of them
     harmless, then, in the absence of actual notice to the Company or the
     Trustee that such Security has been acquired by a bona fide purchaser, the
     Company shall execute and the Trustee shall authenticate and deliver, in
     lieu of any such destroyed, lost or stolen Security, a new Security of like
     tenor and principal amount and bearing a number not contemporaneously
     outstanding.

          In case any such mutilated, destroyed, lost or stolen Security has
become or is about to become due and payable, the Company in its discretion, but
subject to any conversion rights, may, instead of issuing a new Security, pay
such Security, upon satisfaction of the conditions set forth in the preceding
paragraph.

          Upon the issuance of any new Security under this Section 3.8, the
Company may require the payment of a sum sufficient to cover any tax or other
governmental charge that may

                                       41
<PAGE>   49

be imposed in relation thereto (other than any stamp and other duties, if any,
which may be imposed in connection therewith by the United States or any
political subdivision thereof or therein, which shall be paid by the Company)
and any other expenses (including the fees and expenses of the Trustee)
connected therewith.

          Every new Security issued pursuant to this Section 3.8 in lieu of any
mutilated, destroyed, lost or stolen Security shall constitute an original
additional contractual obligation of the Company, whether or not the mutilated,
destroyed, lost or stolen Security shall be at any time enforceable by anyone,
and such new Security 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 3.8 are exclusive and shall preclude
(to the extent lawful) all other rights and remedies of any Holder with respect
to the replacement or payment of mutilated, destroyed, lost or stolen
Securities.

          SECTION 3.9 PAYMENT OF INTEREST; INTEREST RIGHTS PRESERVED. Interest
on any Security which is payable, and is punctually paid or duly provided for,
on any Interest Payment Date shall be paid to the Person in whose name that
Security (or one or more Predecessor Securities) is registered at the close of
business on the Regular Record Date for such interest.

          Any interest on any Security which is payable, but is not punctually
paid or duly provided for, on any Interest Payment Date (herein called
"Defaulted Interest") shall forthwith cease to be payable to the Holder on the
relevant Regular Record Date by virtue of having been such Holder, and such
Defaulted Interest may be paid by the Company, at its election in each case, as
provided in Clause (1) or (2) below:

          (1) The Company may elect to make payment of any Defaulted Interest to
     the Persons in whose names the Securities (or their respective Predecessor
     Securities) are registered at the close of business on a Special Record
     Date for the payment of such Defaulted Interest, which shall be fixed in
     the following manner. The Company shall notify the Trustee in writing of
     the amount of Defaulted Interest proposed to be paid on each Security, the
     date of the proposed payment and the Special Record Date, and at the same
     time the Company shall deposit with the Trustee an amount of money equal to
     the aggregate amount proposed to be paid in respect of such Defaulted
     Interest or shall make arrangements satisfactory to the Trustee for such
     deposit prior to the date of the proposed payment, such money when
     deposited to be held in trust for the benefit of the Persons entitled to
     such Defaulted Interest as in this Clause provided. The Special Record Date
     for the payment of such Defaulted Interest shall be not more than 15 days
     and not less than 10 days prior to the date of the proposed payment and not
     less than 10 days after the receipt by the Trustee of the notice of the
     proposed payment. The Trustee, 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 at such Holder's address as it appears in
     the Security Register, not less than 10 days prior to such Special Record
     Date. Notice of the proposed payment of such Defaulted Interest and the
     Special Record Date therefor having been so mailed, such Defaulted Interest
     shall be paid to the Persons in whose names the Securities (or their

                                       42
<PAGE>   50

     respective Predecessor Securities) are registered at the close of business
     on such Special Record Date and shall no longer be payable pursuant to the
     following Clause (2).

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

          Subject to the foregoing provisions of this Section and Section 3.5,
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.

          Interest on any Security which is converted in accordance with Section
12.2 during a Record Date Period shall be payable in accordance with the
provisions of Section 12.2.

          SECTION 3.10 PERSONS DEEMED OWNERS. Prior to due presentment of a
Security for registration of transfer, the Company, the Trustee, any Paying
Agent and any agent of the Company, the Trustee or any Paying Agent 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, premium, if any,
and (subject to Section 3.9) interest on such Security and for all other
purposes whatsoever, whether or not such Security be overdue, and neither the
Company, the Trustee, any Paying Agent nor any agent of the Company, the Trustee
or any Paying Agent shall be affected by notice to the contrary.

          SECTION 3.11 CANCELLATION. All Securities surrendered for payment,
redemption, repurchase, registration of transfer or exchange or conversion
shall, if surrendered to any Person other than the Trustee, be delivered to the
Trustee. All Securities so delivered to the Trustee shall be canceled promptly
by the Trustee (or its agent). No Securities shall be authenticated in lieu of
or in exchange for any Securities canceled as provided in this Section 3.11. The
Trustee shall dispose of all canceled Securities in accordance with applicable
law and its customary practices in effect from time to time.

          SECTION 3.12 COMPUTATION OF INTEREST. Interest on the Securities shall
be computed on the basis of a 360-day year of twelve 30-day months.

          SECTION 3.13 CUSIP NUMBERS. The Company in issuing Securities may use
"CUSIP" numbers (if then generally in use) in addition to serial numbers; if so,
the Trustee shall use such CUSIP numbers in addition to serial numbers in
notices of redemption and repurchase as a convenience to Holders; provided that
any such notice may state that no representation is made as to the correctness
of such CUSIP numbers either as printed on the Securities or as contained in any
notice of a redemption or repurchase and that reliance may be placed only on the
serial or other identification numbers printed on the Securities, and any such
redemption or repurchase shall not be affected by any defect in or omission of
such CUSIP numbers.

                                       43
<PAGE>   51

                                   ARTICLE IV

                           SATISFACTION AND DISCHARGE

          SECTION 4.1 SATISFACTION AND DISCHARGE OF INDENTURE. This Indenture
shall upon Company Request cease to be of further effect (except as to any
surviving rights of conversion, or registration of transfer or exchange, or
replacement of Securities herein expressly provided for and in the form of
Securities set forth in Section 2.2 and the Company's obligations to the Trustee
pursuant to Section 6.7), and the Trustee, at the expense of the Company, shall
execute proper instruments in form and substance satisfactory to the Trustee
acknowledging satisfaction and discharge of this Indenture, when

          (1) either

          (i) all Securities theretofore authenticated and delivered (other
     than (A) Securities which have been destroyed, lost or stolen and which
     have been replaced or paid as provided in Section 3.8 and (B) Securities
     for whose payment money has theretofore been deposited in trust or
     segregated and held in trust by the Company and thereafter repaid to the
     Company or discharged from such trust, as provided in Section 10.3) have
     been delivered to the Trustee for cancellation; or

          (ii) all such Securities not theretofore delivered to the Trustee or
     its agent for cancellation (other than Securities referred to in clauses
     (A) and (B) of clause (1)(i) above)

               (a) have become due and payable, or

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

               (c) 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 clause (a), (b) or (c) above,
          has deposited or caused to be deposited with the Trustee as trust
          funds (immediately available to the Holders in the case of clause (a))
          in trust for the purpose an amount in cash sufficient to pay and
          discharge the entire indebtedness on such Securities not theretofore
          delivered to the Trustee for cancellation, for principal, premium, if
          any, and interest to the date of such deposit (in the case of
          Securities which have become due and payable) or to the Stated
          Maturity or Redemption Date, as the case may be;

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

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

                                       44
<PAGE>   52

          Notwithstanding the satisfaction and discharge of this Indenture, the
obligations of the Company to the Trustee under Section 6.7, the obligations of
the Company to any Authenticating Agent under Section 6.12, if money shall have
been deposited with the Trustee pursuant to clause (1)(ii) of this Section 4.1,
the obligations of the Trustee under Section 4.2 and the last paragraph of
Section 10.3 and the obligations of the Company and the Trustee under Section
3.5 and Article XII shall survive. Funds held in trust pursuant to this Section
are not subject to the provisions of Article XIII.

          SECTION 4.2 APPLICATION OF TRUST MONEY. Subject to the provisions of
the last paragraph of Section 10.3, all money or property deposited with the
Trustee pursuant to Section 4.1 and in accordance with the provisions of Article
XIII shall be held in trust for the sole benefit of the Holders and not be
subject to the subordination provisions of Article XIII, and such monies shall
be applied by the Trustee, in accordance with the provisions of the Securities
and this Indenture, to the payment, either directly or through any Paying Agent,
to the Persons entitled thereto, of the principal, premium, if any, and interest
for whose payment such money has been deposited with the Trustee.

          All moneys deposited with the Trustee pursuant to Section 4.1 (and
held by it or any Paying Agent) for the payment of Securities subsequently
converted shall be returned to the Company upon Company Request.

          The Company shall pay and indemnify the Trustee against any tax, fee
or other charge imposed or assessed against all money deposited with the Trustee
pursuant to Section 4.1 (other than income taxes and franchise taxes incurred or
payable by the Trustee and such other taxes, fees or charges incurred or payable
by the Trustee that are not directly the result of the deposit of such money
with the Trustee).

                                   ARTICLE V

                                    REMEDIES

          SECTION 5.1 EVENTS OF DEFAULT.

          "Event of Default", wherever used herein, means any one of the
following events (whatever the reason for such Event of Default and whether it
shall be occasioned by the provisions of Article XIII 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):

          (1) default in the payment of the principal of or premium, if any, on
     any Security at its Maturity, whether or not such payment is prohibited by
     the subordination provisions of the Securities or of this Indenture; or

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

                                       45
<PAGE>   53

          (3) failure by the Company to give a Company Notice in accordance with
     Section 14.3 whether or not such Company Notice is prohibited by the
     subordination provisions of the Securities or the Indenture; or

          (4) default in the performance, or breach, of any covenant or warranty
     of the Company in this Indenture (other than a covenant or warranty a
     default in the performance or breach of which is specifically dealt with
     elsewhere in this Section), 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

          (5) any indebtedness under any bonds, debentures, notes or other
     evidences of indebtedness for money borrowed (or guarantee thereof) by the
     Company or any Significant Subsidiary or under any mortgage, indenture or
     instrument under which there may be issued or by which there may be secured
     or evidenced any indebtedness for money borrowed by the Company or any
     Significant Subsidiary (an "Instrument") with an aggregate principal amount
     in excess of U.S. $25,000,000, whether such indebtedness now exists or
     shall hereafter be created, is not paid at final maturity under any
     Instrument (either at its stated maturity or upon acceleration thereof),
     and such indebtedness is not discharged, or such acceleration is not
     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 Outstanding Securities a written notice specifying
     such default and requiring the Company to cause such indebtedness to be
     discharged or cause such default to be cured or waived or such acceleration
     to be rescinded or annulled and stating that such notice is a "Notice of
     Default" hereunder; or

          (6) the entry by a court having jurisdiction in the premises of (A) a
     decree or order for relief in respect of the Company or any Significant
     Subsidiary in an involuntary case or proceeding under any applicable
     Federal or State bankruptcy, insolvency, reorganization or other similar
     law or (B) a decree or order adjudging the Company or any Significant
     Subsidiary a bankrupt or insolvent, or approving as properly filed a
     petition seeking reorganization, arrangement, adjustment or composition of
     or in respect of the Company or any Significant Subsidiary under any
     applicable Federal or State law, or appointing a custodian, receiver,
     liquidator, assignee, trustee, sequestrator or other similar official of
     the Company or any Significant Subsidiary or of any substantial part of the
     property of either, or ordering the winding up or liquidation of its
     affairs, and the continuance of any such decree or order for relief or any
     such other decree or order unstayed and in effect for a period of 60
     consecutive days; or

          (7) the commencement by the Company or any Significant Subsidiary of a
     voluntary case or proceeding under any applicable Federal or State
     bankruptcy,

                                       46
<PAGE>   54

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

          SECTION 5.2 ACCELERATION OF MATURITY; RESCISSION AND ANNULMENT. If an
Event of Default (other than an Event of Default specified in Section 5.1(6) or
5.1(7) with respect to the Company) occurs and is continuing, then in every such
case the Trustee or the Holders of not less than 25% in principal amount of the
Outstanding Securities may, subject to the provisions of Article XIII, 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 and all accrued interest thereon
shall become immediately due and payable. If an Event of Default specified in
Section 5.1(6) or 5.1(7) with respect to the Company occurs, the principal of,
and accrued interest on, all the Securities shall, subject to the provisions of
Article XIII, ipso facto become immediately due and payable without any
declaration or other Act of the Holders or any act on the part of the Trustee.

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

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

               (i) all overdue interest on all Securities,

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

               (iii) to the extent permitted by applicable law, interest upon
          overdue interest, if any, at the rate prescribed therefor by 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;

                                       47
<PAGE>   55

          (2) all Events of Default, other than the nonpayment of the principal
     of and any premium and interest on, Securities which have become due solely
     by such declaration of acceleration, have been cured or waived as provided
     in Section 5.13; and

          (3) such rescission and annulment would not conflict with any judgment
     or decree issued in appropriate judicial proceedings regarding the payment
     by the Trustee to the Holders of the amounts referred to in 5.2(1).

          No rescission or annulment referred to above shall affect any
subsequent default or impair any right consequent thereon.

          SECTION 5.3 COLLECTION OF INDEBTEDNESS AND SUITS FOR ENFORCEMENT BY
TRUSTEE. The Company covenants that if:

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

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

the Company will, upon demand of the Trustee but subject to the provisions of
Article XIII pay to it, for the benefit of the Holders of such Securities the
whole amount then due and payable on such Securities for principal and interest
and interest on any overdue principal and premium, if any, and, to the extent
permitted by applicable law, on any overdue interest, if any, at the rate
prescribed therefor by such Securities, and in addition thereto, such further
amount as shall be sufficient to cover the reasonable 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, may
prosecute such proceeding to judgment or final decree and may enforce the same
against the Company or any other obligor upon the 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 the Securities, wherever
situated.

          If an Event of Default occurs and is continuing, the Trustee may in
its discretion proceed to protect and enforce its rights and the rights of the
Holders 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 5.4 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 the creditors of either, the Trustee
(irrespective of whether the principal of, and any interest on, the Securities
shall then be

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<PAGE>   56

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 or interest) shall be entitled and
empowered, by intervention in such proceeding or otherwise,

          (1) to file and prove a claim for the whole amount of principal,
     premium, if any, and interest owing and unpaid in respect of the Securities
     and take such other actions, including participating as a member, voting or
     otherwise, of any official committee of creditors appointed in such matter,
     and to file such other papers or documents, in each of the foregoing cases,
     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 of Securities allowed in such judicial proceeding, and

          (2) to collect and receive any moneys or other property payable or
     deliverable on any such claim and to distribute the same; and any
     custodian, receiver, assignee, trustee, liquidator, sequestrator or other
     similar official in any such judicial proceeding is hereby authorized by
     each Holder of Securities to make such payments to the Trustee and, in the
     event that the Trustee shall consent to the making of such payments
     directly to the Holders of Securities to pay to the Trustee any amount due
     to it for the reasonable compensation, expenses, disbursements and advances
     of the Trustee, its agents and counsel and any other amounts due the
     Trustee under Section 6.7.

          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 such Holders, vote for the
election of a trustee in bankruptcy or similar official.

          SECTION 5.5 TRUSTEE MAY ENFORCE CLAIMS WITHOUT POSSESSION OF
SECURITIES. All rights of action and claims under this Indenture or the
Securities may be prosecuted and enforced by the Trustee without the possession
of any of the Securities or the production thereof in any proceeding relating
thereto, and any such proceeding instituted by the Trustee shall be brought in
its own name as trustee of an express trust, and any recovery of judgment shall,
after provision for the payment of the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel, be for the
ratable benefit of the Holders of the Securities in respect of which judgment
has been recovered.

          SECTION 5.6 APPLICATION OF MONEY COLLECTED. Subject to Article XIII,
any money or property collected by the Trustee pursuant to this Article V 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, premium,
if any, or interest, upon presentation of the Securities and the notation
thereon of the payment if only partially paid and upon surrender thereof if
fully paid:

          FIRST: To the payment of all amounts due the Trustee under Section
     6.7;

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<PAGE>   57

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

          THIRD: To such other Person or Persons, if any, to the extent entitled
     thereto; and

          FOURTH: Any remaining amounts shall be repaid to the Company.

          SECTION 5.7 LIMITATION ON SUITS. No Holder of any Security shall have
any right to institute any proceeding, judicial or otherwise, with respect to
this Indenture, or for the appointment of a receiver or trustee, or for any
other remedy hereunder, unless:

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

          (2) the Holders of not less than 25% in principal amount of the
     Outstanding Securities shall have made written request to the Trustee to
     institute proceedings in respect of such Event of Default in its own name
     as Trustee hereunder;

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

          (4) the Trustee for 60 days after its receipt of such notice and
     receipt of indemnity has failed to institute any such proceeding; and

          (5) no direction inconsistent with such written request has been given
     to the Trustee during such 60 day period by the Holders of a majority in
     principal amount of the Outstanding Securities, 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 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 5.8 UNCONDITIONAL RIGHT OF HOLDERS TO RECEIVE PRINCIPAL,
PREMIUM AND INTEREST AND TO CONVERT. Notwithstanding any other provision in this
Indenture, but subject to the provisions of Article XIII, the Holder of any
Security shall have the right, which is absolute and unconditional, to receive
payment of the principal of, premium, if any, and (subject to Section 3.9)
interest on such Security on the respective Stated Maturities 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 Article XII, 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.

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<PAGE>   58

          SECTION 5.9 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, subject to any determination in such
proceeding, the Company, the Trustee and the Holders of Securities shall be
restored severally and respectively to their former positions hereunder and
thereafter all rights and remedies of the Trustee and such 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 3.8, 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.

          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 any acquiescence therein.
Every right and remedy given by this Article V or by law to the Trustee or to
the Holders of Securities may be exercised from time to time, and as often as
may be deemed expedient, by the Trustee or (subject to the limitations contained
in this Indenture) by the Holders of Securities as the case may be.

          SECTION 5.12 CONTROL BY HOLDERS OF SECURITIES. Subject to Section 6.3,
the Holders of 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, provided that

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

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

          (3) the Trustee need not take any action which might involve it in
     personal liability or be unjustly prejudicial to the Holders of Securities
     not consenting.

          SECTION 5.13 WAIVER OF PAST DEFAULTS. The Holders, either (i) through
the written consent of not less than a majority in principal amount of the
Outstanding Securities or (ii) by the adoption of a resolution, at a meeting of
Holders of the Outstanding Securities at which a quorum is present, by the
Holders of at least 66 2/3% in principal amount of the Outstanding Securities
represented at such meeting, may on behalf of the Holders of all the Securities
waive any past default hereunder and its consequences, except a default (A) in
the payment of the principal of, premium, if any, or interest on any Security,
or (B) in respect of a

                                       51
<PAGE>   59

covenant or provision hereof which under Article VIII cannot be modified or
amended without the consent of the Holder of each Outstanding Security affected.

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

          SECTION 5.14 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 any suit against
the Trustee for any action taken, suffered or omitted by it as Trustee, the
filing by any party litigant in such suit of an 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 5.14 shall not apply to
any suit instituted by the Company, 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 of any Security for the enforcement of the payment of
the principal of, premium, if any, or interest on any Security on or after the
respective Stated Maturity or Maturities expressed in such Security (or, in the
case of redemption or repurchase, on or after the Redemption Date or Repurchase
Date, as the case may be) or for the enforcement of the right to convert any
Security in accordance with Article XII.

          SECTION 5.15 WAIVER OF STAY, USURY OR EXTENSION LAWS. The Company
covenants (to the extent that it may lawfully do so) that it will not at any
time insist upon, or plead, or in any manner whatsoever claim or take the
benefit or advantage of, any stay, usury or extension law wherever enacted, now
or at any time hereafter in force, which may affect the covenants or the
performance of this Indenture; and the Company (to the extent that it may
lawfully do so) hereby expressly waives all benefit or advantage of any such law
and covenants that it will not hinder, delay or impede by reason of such law the
execution of any power herein granted to the Trustee, but will suffer and permit
the execution of every such power as though no such law had been enacted.

                                   ARTICLE VI

                                   THE TRUSTEE

          SECTION 6.1 CERTAIN DUTIES AND RESPONSIBILITIES.

          (1) Except during the continuance of an Event of Default,

          (i) the Trustee undertakes to perform such duties and only such
     duties as are specifically set forth in this Indenture, and no implied
     covenants or obligations shall be read into this Indenture against the
     Trustee; and

                                       52
<PAGE>   60

          (ii) in the absence of bad faith on its part, the Trustee may
     conclusively rely, as to the truth of the statements and the correctness of
     the opinions expressed therein, upon certificates or opinions furnished to
     the Trustee and conforming to the requirements of this Indenture, but in
     the case of any such certificates or opinions which by any provision hereof
     are specifically required to be furnished to the Trustee, the Trustee shall
     be under a duty to examine the same to determine whether or not they
     conform to the requirements of this Indenture, but not to verify the
     contents thereof.

          (2) In case an Event of Default has occurred and is continuing, the
Trustee shall exercise such of the rights and powers vested in it by this
Indenture, and use the same degree of care and skill in their exercise, as a
prudent man would exercise or use under the circumstances in the conduct of his
own affairs.

          (3) No provision of this Indenture shall be construed to relieve the
Trustee from liability for its own negligent action, its own negligent failure
to act, or its own willful misconduct, except that

          (i) this paragraph (3) shall not be construed to limit the effect of
     paragraph (1) of this Section;

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

          (iii) the Trustee shall not be liable with respect to any action
     taken, suffered or omitted to be taken by it in good faith in accordance
     with the 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; and

          (iv) no provision of this Indenture shall require the Trustee to
     expend or risk its own funds or otherwise incur any financial liability in
     the performance of any of its duties hereunder, or in the exercise of any
     of its rights or powers, if it shall have reasonable grounds for believing
     that repayment of such funds or adequate indemnity against such risk or
     liability is not reasonably assured to it.

          (4) Whether or not therein expressly so provided, every provision of
this Indenture relating to the conduct or affecting the liability of or
affording protection to the Trustee shall be subject to the provisions of this
Section.

          SECTION 6.2 NOTICE OF DEFAULTS. Within 120 days after the occurrence
of any default hereunder as to which the Trustee has received written notice,
the Trustee shall give to all Holders of Securities, in the manner provided in
Section 1.6, notice of such default, unless such default shall have been cured
or waived; provided, however, that, except in the case of a default in the
payment of the principal of, premium, if any, or interest on any Security the
Trustee shall be protected in withholding such notice if and so long as the
board of directors, the executive committee or a trust committee of directors or
Responsible Officers of the Trustee in good faith determines that the
withholding of such notice is in the interest of the Holders; and provided,

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<PAGE>   61

further, that in the case of any default of the character specified in Section
5.1(4), no such notice to Holders of Securities shall be given until at least 60
days after the occurrence thereof or, if applicable, the cure period specified
therein. 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.

          SECTION 6.3 CERTAIN RIGHTS OF TRUSTEE. Subject to the provisions of
Section 6.1 and the Trust Indenture Act Sections 315(a) through 315(d):

          (1) the Trustee may rely, and shall be protected in acting or
     refraining from acting, upon any resolution, Officers' Certificate, other
     certificate, statement, instrument, opinion, report, notice, request,
     direction, consent, order, bond, debenture, note, coupon, other evidence of
     indebtedness or other paper or document (collectively, the "Documents")
     believed by it to be genuine and to have been signed or presented by the
     proper party or parties, and the Trustee need not investigate any fact or
     matter stated in such Documents;

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

          (3) 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 the one specifically prescribed) may, in the absence of bad
     faith on its part, request and rely upon an Officers' Certificate or
     Opinion of Counsel;

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

          (5) the Trustee shall be under no obligation to exercise any of the
     rights or powers vested in it by this Indenture at the request or direction
     of any of the Holders of Securities pursuant to this Indenture, unless such
     Holders shall have furnished and delivered to the Trustee reasonable
     security or indemnity against the costs, expenses and liabilities which
     might be incurred by it in compliance with such request or direction;

          (6) 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, coupon, other evidence of indebtedness or other
     paper or document, but the Trustee 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; and

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

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<PAGE>   62

          SECTION 6.4 NOT RESPONSIBLE FOR RECITALS OR ISSUANCE OF SECURITIES.
The recitals contained herein and in the Securities (except the Trustee's
certificates of authentication) shall be taken as the statements of the Company,
and the Trustee assumes no responsibility for their correctness. The Trustee
makes no representations as to the validity or sufficiency of this Indenture, of
the Securities or of the Common Stock issuable upon the conversion of the
Securities. The Trustee shall not be accountable for the use or application by
the Company of Securities or the proceeds thereof.

          SECTION 6.5 MAY HOLD SECURITIES, ACT AS TRUSTEE UNDER OTHER
INDENTURES. The Trustee, any Authenticating Agent, any Paying Agent, any
Conversion Agent or any other agent of the Company or the Trustee, in its
individual or any other capacity, may become the owner or pledgee of Securities
and may otherwise deal with the Company with the same rights it would have if it
were not Trustee, Authenticating Agent, Paying Agent, Conversion Agent or such
other agent.

          The Trustee may become and act as trustee under other indentures under
which other securities, or certificates of interest or participation in other
securities, of the Company are outstanding in the same manner as if it were not
Trustee hereunder.

          SECTION 6.6 MONEY HELD IN TRUST. Money or property held by the Trustee
in trust hereunder need not be segregated from other funds except to the extent
required by law. The Trustee shall be under no liability for interest on any
money received by it hereunder except as otherwise agreed in writing with the
Company.

          SECTION 6.7 COMPENSATION AND REIMBURSEMENT. The Company agrees

          (1) to pay to the Trustee from time to time such reasonable
     compensation as the Company and the Trustee shall from time to time agree
     in writing for its acceptance of this Indenture and for all services
     rendered by it hereunder (which compensation shall not be limited by any
     provision of law in regard to the compensation of a trustee of an express
     trust);

          (2) except as otherwise expressly provided herein, to reimburse the
     Trustee upon its request for all reasonable expenses, disbursements and
     advances incurred or made by the Trustee (including costs and expenses of
     enforcing this Indenture and defending itself against any claim (whether
     asserted by the Company, any Holder of Securities or any other Person) or
     liability in connection with the exercise of any of its powers or duties
     hereunder) in accordance with any provision of this Indenture (including
     the reasonable compensation and the expenses and disbursements of its
     agents and counsel), except any such expense, disbursement or advance as
     may be attributable to its negligence or bad faith; and

          (3) to indemnify the Trustee (and its directors, officers, employees
     and agents) for, and to hold it harmless against, any loss, liability or
     expense incurred without negligence or bad faith on its part, arising out
     of or in connection with the acceptance or

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<PAGE>   63

     administration of this trust, including the reasonable costs, expenses and
     reasonable attorneys' fees of defending itself against any claim or
     liability in connection with the exercise or performance of any of its
     powers or duties hereunder.

          When the Trustee incurs expenses or renders services in connection
with an Event of Default specified in Section 5.1(6) or Section 5.1(7), the
expenses (including the reasonable charges of its counsel) and the compensation
for the services are intended to constitute expenses of the administration under
any applicable Federal or state bankruptcy, insolvency or other similar law.

          The provisions of this Section shall survive the termination of this
Indenture or the earlier resignation or removal of the Trustee.

          To secure the Company's payment obligations in this Section 6.7, the
Trustee shall have a claim prior to the Securities on all money and property
held or collected by the Trustee other than money and property held in trust to
pay principal of, premium, if any, and interest on particular Securities.

          SECTION 6.8 CORPORATE TRUSTEE REQUIRED; ELIGIBILITY. There shall at
all times be a Trustee hereunder which shall be a Person that is eligible
pursuant to the Trust Indenture Act to act as such, having (or being part of a
holding company group with) a combined capital and surplus of at least U.S.
$50,000,000, subject to supervision or examination by federal or state
authority, and in good standing. If such corporation publishes reports of
condition at least annually, pursuant to law or to the requirements of said
supervising or examining authority, then for the purposes of this Section, the
combined capital and surplus of such corporation shall be deemed to be its
combined capital and surplus as set forth in its most recent report of condition
so published. If at any time the Trustee shall cease to be eligible in
accordance with the provisions of this Section, it shall resign immediately in
the manner and with the effect hereinafter specified in this Article and a
successor shall be appointed pursuant to Section 6.9.

          SECTION 6.9 RESIGNATION AND REMOVAL; APPOINTMENT OF SUCCESSOR.

          (1) No resignation or removal of the Trustee and no appointment of a
successor Trustee pursuant to this Article shall become effective until the
acceptance of appointment by the successor Trustee in accordance with the
applicable requirements of Section 6.10.

          (2) The Trustee may resign at any time by giving written notice
thereof to the Company. If the instrument of acceptance by a successor Trustee
required by Section 6.10 shall not have been delivered to the Trustee within 30
days after the giving of such notice of resignation, the resigning Trustee may
petition any court of competent jurisdiction for the appointment of a successor
Trustee.

          (3) The Trustee may be removed at any time by an Act of the Holders of
a majority in principal amount of the Outstanding Securities, delivered to the
Trustee and the Company. If the instrument of acceptance by a successor Trustee
required by Section 6.10 shall not have been delivered to the Trustee within 30
days after the giving of such notice of removal, the removed Trustee may
petition any court of competent jurisdiction for the appointment of a successor
Trustee.

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<PAGE>   64

          (4) If at any time:

          (i) the Trustee shall cease to be eligible under Section 6.8 and
     shall fail to resign after written request therefor by the Company or by
     any Holder of a Security who has been a bona fide Holder of a Security for
     at least six months, or

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

then, in any such case (i) the Company by a Board Resolution may remove the
Trustee, or (ii) subject to Section 5.14, any Holder of a Security who has been
a bona fide Holder of a Security for at least six months may, on behalf of
himself and all others similarly situated, petition any court of competent
jurisdiction for the removal of the Trustee and the appointment of a successor
Trustee.

          (5) If the Trustee shall resign, be removed or become incapable of
acting, or if a vacancy shall occur in the office of Trustee for any cause, the
Company, by a Board Resolution, shall promptly appoint a successor Trustee and
shall comply with the applicable requirements of this Section and Section 6.10.
If, within one year after such resignation, removal or incapability, or the
occurrence of such vacancy, a successor Trustee shall be appointed by Act of the
Holders of a majority in principal amount of the Outstanding Securities
delivered to the Company and the retiring Trustee, the successor Trustee so
appointed shall, forthwith upon its acceptance of such appointment in accordance
with the applicable requirements of Section 6.10, become the successor Trustee
and supersede the successor Trustee appointed by the Company. If no successor
Trustee shall have been so appointed by the Company or the Holders of Securities
and accepted appointment in the manner required by this Section and Section
6.10, any Holder of a Security who has been a bona fide Holder of a Security for
at least six months may, on behalf of himself and all others similarly situated,
petition any court of competent jurisdiction for the appointment of a successor
Trustee.

          (6) The Company shall give notice of each resignation and each removal
of the Trustee and each appointment of a successor Trustee to all Holders of
Securities in the manner provided in Section 1.6. Each notice shall include the
name of the successor Trustee and the address of its Corporate Trust Office.

          SECTION 6.10 ACCEPTANCE OF APPOINTMENT BY SUCCESSOR. Every successor
Trustee appointed hereunder shall execute, acknowledge and deliver to the
Company and to the retiring Trustee an instrument accepting such appointment,
and thereupon the resignation or removal of the retiring Trustee shall become
effective and such successor Trustee, without any further act, deed or
conveyance, shall become vested with all the rights, powers, trusts and duties
of the retiring Trustee; but, on the request of the Company or the successor
Trustee, such retiring Trustee shall, upon payment of its charges, execute and
deliver an instrument transferring to such

                                       57
<PAGE>   65

successor Trustee all the rights, powers and trusts of the retiring Trustee and
shall duly assign, transfer and deliver to such successor Trustee all property
and money held by such retiring Trustee hereunder. Upon request of any such
successor Trustee, the Company shall execute any and all instruments for more
fully and certainly vesting in and confirming to such successor Trustee all such
rights, powers and trusts.

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

          SECTION 6.11 MERGER, CONVERSION, CONSOLIDATION OR SUCCESSION TO
BUSINESS. Any corporation into which the Trustee may be merged or converted or
with which it may be consolidated, or any corporation resulting from any merger,
conversion or consolidation to which the Trustee shall be a party, or any
corporation succeeding to all or substantially all of the corporate trust
business of the Trustee (including the trust created by this Indenture), shall
be the successor of the Trustee hereunder, provided such corporation shall be
otherwise eligible under this Article, without the execution or filing of any
paper or any further act on the part of any of the parties hereto. In case any
Securities shall have been authenticated, but not delivered, by the Trustee then
in office, any successor by merger, conversion or consolidation to such
authenticating Trustee may adopt such authentication and deliver the Securities
so authenticated with the same effect as if such successor Trustee had itself
authenticated such Securities.

          SECTION 6.12 AUTHENTICATING AGENTS. The Trustee may, with the consent
of the Company, appoint an Authenticating Agent or Agents acceptable to the
Company with respect to the Securities which shall be authorized to act on
behalf of the Trustee to authenticate Securities issued upon exchange or
substitution pursuant to this Indenture.

          Securities authenticated by an Authenticating Agent shall be entitled
to the benefits of this Indenture and shall be valid and obligatory for all
purposes as if authenticated by the Trustee hereunder, and every reference in
this Indenture to the authentication and delivery of Securities by the Trustee
or the Trustee's certificate of authentication shall be deemed to include
authentication and delivery on behalf of the Trustee by an Authenticating Agent
and a certificate of authentication executed on behalf of the Trustee by an
Authenticating Agent. Each Authenticating Agent shall be subject to acceptance
by the Company and shall at all times be a corporation organized and doing
business under the laws of the United States of America, any State thereof or
the District of Columbia, authorized under such laws to act as Authenticating
Agent and subject to supervision or examination by government or other fiscal
authority. If at any time an Authenticating Agent shall cease to be eligible in
accordance with the provisions of this Section 6.12, such Authenticating Agent
shall resign immediately in the manner and with the effect specified in this
Section 6.12.

          Any corporation into which an Authenticating Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or consolidation to which such Authenticating Agent
shall be a party, or any corporation succeeding to the corporate agency or
corporate trust business of an Authenticating Agent, shall continue to be an
Authenticating Agent, provided such corporation shall be otherwise eligible
under this Section 6.12, without the execution or filing of any paper or any
further act on the part of the Trustee or the Authenticating Agent.

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<PAGE>   66

          An Authenticating Agent may resign at any time by giving written
notice thereof to the Trustee and to the Company. The Trustee may at any time
terminate the agency of an Authenticating Agent by giving written notice thereof
to such Authenticating Agent and to the Company. Upon receiving such a notice of
resignation or upon such a termination, or in case at any time such
Authenticating Agent shall cease to be eligible in accordance with the
provisions of this Section 6.12, the Trustee may appoint a successor
Authenticating Agent which shall be subject to acceptance by the Company. Any
successor Authenticating Agent upon acceptance of its appointment hereunder
shall become vested with all the rights, powers and duties of its predecessor
hereunder, with like effect as if originally named as an Authenticating Agent.
No successor Authenticating Agent shall be appointed unless eligible under the
provisions of this Section 6.12.

          The Company agrees to pay to each Authenticating Agent from time to
time reasonable compensation for its services under this Section 6.12.

          If an Authenticating Agent is appointed with respect to the Securities
pursuant to this Section 6.12, the Securities may have endorsed thereon, in
addition to or in lieu of the Trustee's certification of authentication, an
alternative certificate of authentication in the following form:

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

                                       WILMINGTON TRUST COMPANY,
                                       as Trustee

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

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

          SECTION 6.13 DISQUALIFICATION; CONFLICTING INTERESTS. If the Trustee
has or shall acquire a conflicting interest within the meaning of the Trust
Indenture Act, the Trustee shall either eliminate such interest or resign, to
the extent and in the manner provided by, and subject to the provisions of, the
Trust Indenture Act and this Indenture.

          SECTION 6.14 PREFERENTIAL COLLECTION OF CLAIMS AGAINST COMPANY. If and
when the Trustee shall be or become a creditor of the Company (or any other
obligor upon the Securities), the Trustee shall be subject to the provisions of
the Trust Indenture Act regarding the collection of claims against the Company
(or any such other obligor).

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<PAGE>   67

                                  ARTICLE VII

              CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE

          SECTION 7.1 COMPANY MAY CONSOLIDATE, ETC., ONLY ON CERTAIN TERMS. The
Company shall not consolidate with or merge into any other Person or convey,
transfer or lease all its properties and assets substantially as an entirety to
any Person, and the Company shall not permit any Person to consolidate with or
merge into the Company or convey, transfer, sell or lease such Person's
properties and assets substantially as an entirety to the Company unless:

          (1) the Person formed by such consolidation or into or with which the
     Company is merged or the Person to which the properties and assets of the
     Company are so conveyed, transferred, sold or leased shall be a
     corporation, limited liability company, partnership or trust organized and
     validly existing under the laws of the United States of America, any State
     thereof or the District of Columbia and, if other than the Company, shall
     expressly assume, by an indenture supplemental hereto, executed and
     delivered to the Trustee, in form satisfactory to the Trustee, the due and
     punctual payment of the principal of, premium, if any, and interest on all
     of the Securities as applicable, and the performance or observance of every
     covenant of this Indenture on the part of the Company to be performed or
     observed and shall have provided for conversion rights in accordance with
     Article XII;

          (2) immediately after giving effect to such transaction, no Event of
     Default, and no event that after notice or lapse of time or both, would
     become an Event of Default, shall have occurred and be continuing; and

          (3) the Company has delivered to the Trustee an Officers' Certificate
     and an Opinion of Counsel, each stating that such consolidation, merger,
     conveyance, transfer or lease and, if a supplemental indenture is required
     in connection with such transaction, such supplemental indenture comply
     with this Article and that all conditions precedent herein provided for
     relating to such transaction have been complied with, together with any
     documents required under Section 8.3.

          SECTION 7.2 SUCCESSOR SUBSTITUTED. Upon any consolidation of the
Company with, or merger of the Company into any other Person or any conveyance,
transfer or lease of all or substantially all the properties and assets of the
Company in accordance with Section 7.1, the successor Person formed by such
consolidation or into or with which the Company is merged or to which such
conveyance, transfer or lease is made shall succeed to, and be substituted for,
and may exercise every right and power of, the Company under this Indenture with
the same effect as if such successor Person had been named as the Company
herein, and thereafter, except in the case of a lease, the predecessor Person
shall be relieved of all obligations and covenants under this Indenture and the
Securities.

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<PAGE>   68

                                  ARTICLE VIII

                             SUPPLEMENTAL INDENTURES

          SECTION 8.1 SUPPLEMENTAL INDENTURES WITHOUT CONSENT OF HOLDERS OF
SECURITIES. Without the consent of any Holders of Securities the Company, when
authorized by a Board Resolution, and the Trustee, at any time and from time to
time, may enter into one or more indentures supplemental hereto for any of the
following purposes:

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

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

          (3) to secure the Securities; or

          (4) to make provision with respect to the conversion rights of Holders
     of Securities pursuant to Section 12.11 or to make provision with respect
     to the repurchase rights of Holders of Securities pursuant to Section 14.5;
     or

          (5) to comply with the requirements of the Trust Indenture Act or the
     rules and regulations of the Commission thereunder in order to effect or
     maintain the qualification of this Indenture under the Trust Indenture Act,
     as contemplated by this Indenture or otherwise; or

          (6) to evidence and provide for the acceptance of appointment
     hereunder by a successor Trustee; or

          (7) subject to Section 13.12, to make any change in Article XIII that
     would limit or terminate the benefits available to any holder of Senior
     Debt under such Article; or

          (8) to cure any ambiguity, to correct or supplement any provision
     herein which may be inconsistent with any other provision herein or which
     is otherwise defective, or to make any other provisions with respect to
     matters or questions arising under this Indenture as the Company and the
     Trustee may deem necessary or desirable, provided such action pursuant to
     this clause (8) shall not adversely affect the interests of the Holders of
     Securities in any material respect.

          Upon Company Request, accompanied by a Board Resolution authorizing
the execution of any such supplemental indenture, and subject to and upon
receipt by the Trustee of the documents described in Section 8.3 hereof, the
Trustee shall join with the Company in the execution of any supplemental
indenture authorized or permitted by the terms of this Indenture and to make any
further appropriate agreements and stipulations which may be therein contained.

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<PAGE>   69

          SECTION 8.2 SUPPLEMENTAL INDENTURES WITH CONSENT OF HOLDERS OF
SECURITIES. With either (i) the written consent of the Holders of not less than
a majority in principal amount of the Outstanding Securities, by the Act of said
Holders delivered to the Company and the Trustee, or (ii) by the adoption of a
resolution, at a meeting of Holders of the Outstanding Securities at which a
quorum is present, by the Holders of at least 66?% in principal amount of the
Outstanding Securities represented at such meeting, the Company, when authorized
by 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 or affirmative vote of the Holder of each Outstanding Security
affected thereby,

          (1) change the Stated Maturity of the principal of, or any installment
     of interest on, any Security, or reduce the principal amount of, or the
     premium, if any, or the rate of interest payable thereon, or reduce the
     amount payable upon a redemption or mandatory repurchase, or change the
     place or currency of payment of the principal of, premium, if any, or
     interest on any Security (including any payment of Redemption Price or
     Repurchase Price in respect of such Security) or impair the right to
     institute suit for the enforcement of any payment in respect of any
     Security on or after the Stated Maturity thereof (or, in the case of
     redemption or any repurchase, on or after the Redemption Date or Repurchase
     Date, as the case may be) or, except as permitted by Section 12.11,
     adversely affect the right of Holders to convert any Security as provided
     in Article XII, or modify the provisions of this Indenture with respect to
     the subordination of the Securities in a manner adverse to the Holders; or

          (2) reduce the requirements of Section 9.4 for quorum or voting, or
     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 (of compliance with
     certain provisions of this Indenture or certain defaults hereunder and
     their consequences) provided for in this Indenture; or

          (3) modify the obligation of the Company to maintain an office or
     agency in the Borough of Manhattan, The City of New York, pursuant to
     Section 10.2; or

          (4) modify any of the provisions of this Section or Section 5.13 or
     10.12, except to increase any percentage contained herein or therein or to
     provide that certain other provisions of this Indenture cannot be modified
     or waived without the consent of the Holder of each Outstanding Security
     affected thereby; or

          (5) modify the provisions of Article XIV in a manner adverse to the
     Holders.

          It shall not be necessary for any Act of Holders of Securities 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.

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<PAGE>   70

          SECTION 8.3 EXECUTION OF SUPPLEMENTAL INDENTURES. In executing, or
accepting the additional trusts created by, any supplemental indenture permitted
by this Article or the modifications thereby of the trusts created by this
Indenture, the Trustee shall be entitled to receive, and (subject to Sections
6.1 and 6.3) shall be fully protected in relying upon, an Opinion of Counsel
stating that the execution of such supplemental indenture is authorized or
permitted by this Indenture, and that such supplemental indenture has been duly
authorized, executed and delivered by the Company and constitutes a valid and
legally binding obligation of the Company enforceable against the Company in
accordance with its terms. 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 8.4 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 appertaining thereto shall be
bound thereby.

          SECTION 8.5 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 Company and the Trustee, 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.

          SECTION 8.6 NOTICE OF SUPPLEMENTAL INDENTURES. Promptly after the
execution by the Company and the Trustee of any supplemental indenture pursuant
to the provisions of Section 8.2, the Company shall give notice to all Holders
of Securities of such fact, setting forth in general terms the substance of such
supplemental indenture, in the manner provided in Section 1.6. Any failure of
the Company to give such notice, or any defect therein, shall not in any way
impair or affect the validity of any such supplemental indenture.

                                   ARTICLE IX

                        MEETINGS OF HOLDERS OF SECURITIES

          SECTION 9.1 PURPOSES FOR WHICH MEETINGS MAY BE CALLED. A meeting of
Holders of Securities may be called at any time and from time to time pursuant
to this Article to make, give or take any request, demand, authorization,
direction, notice, consent, waiver or other action provided by this Indenture to
be made, given or taken by Holders of Securities.

          SECTION 9.2 CALL, NOTICE AND PLACE OF MEETINGS.

          (1) The Trustee may at any time call a meeting of Holders of
Securities for any purpose specified in Section 9.1, to be held at such time and
at such place in the Borough of Manhattan, The City of New York, as the Trustee
shall determine. Notice of every meeting of

                                       63
<PAGE>   71

Holders of Securities, setting forth the time and the place of such meeting and
in general terms the action proposed to be taken at such meeting, shall be
given, in the manner provided in Section 1.6, not less than 21 nor more than 180
days prior to the date fixed for the meeting.

          (2) In case at any time the Company, pursuant to a Board Resolution,
or the Holders of at least 10% in principal amount of the Outstanding Securities
shall have requested the Trustee to call a meeting of the Holders of Securities
for any purpose specified in Section 9.1, by written request setting forth in
reasonable detail the action proposed to be taken at the meeting, and the
Trustee shall not have mailed the notice of such meeting within 21 days after
receipt of such request or shall not thereafter proceed to cause the meeting to
be held as provided herein, then the Company or the Holders of Securities in the
amount specified, as the case may be, may determine the time and the place in
the Borough of Manhattan, The City of New York, for such meeting and may call
such meeting for such purposes by giving notice thereof as provided in paragraph
(1) of this Section.

          SECTION 9.3 PERSONS ENTITLED TO VOTE AT MEETINGS. To be entitled to
vote at any meeting of Holders of Securities, a Person shall be (i) a Holder of
one or more Outstanding Securities, or (ii) a Person appointed by an instrument
in writing as proxy for a Holder or Holders of one or more Outstanding
Securities by such Holder or Holders. The only Persons who shall be entitled to
be present or to speak at any meeting of Holders shall be the Persons entitled
to vote at such meeting and their counsel, any representatives of the Trustee
and its counsel and any representatives of the Company and its counsel.

          SECTION 9.4 QUORUM; ACTION. The Persons entitled to vote a majority in
principal amount of the Outstanding Securities shall constitute a quorum. In the
absence of a quorum within 30 minutes of the time appointed for any such
meeting, the meeting shall, if convened at the request of Holders of Securities,
be dissolved. In any other case, the meeting may be adjourned for a period of
not less than 10 days as determined by the chairman of the meeting prior to the
adjournment of such meeting. In the absence of a quorum at any such adjourned
meeting, such adjourned meeting may be further adjourned for a period not less
than 10 days as determined by the chairman of the meeting prior to the
adjournment of such adjourned meeting (subject to repeated applications of this
sentence). Notice of the reconvening of any adjourned meeting shall be given as
provided in Section 9.2(1), except that such notice need be given only once not
less than five days prior to the date on which the meeting is scheduled to be
reconvened. Notice of the reconvening of an adjourned meeting shall state
expressly the percentage of the principal amount of the Outstanding Securities
which shall constitute a quorum.

          Subject to the foregoing, at the reconvening of any meeting adjourned
for a lack of a quorum, the Persons entitled to vote 25% in principal amount of
the Outstanding Securities at the time shall constitute a quorum for the taking
of any action set forth in the notice of the original meeting.

          At a meeting or an adjourned meeting duly reconvened and at which a
quorum is present as aforesaid, any resolution and all matters (except as
limited by the proviso to Section 8.2 and except to the extent Section 10.8
requires a different vote) shall be effectively passed and decided if passed or
decided by the lesser of (i) the Holders of not less than a majority in

                                       64
<PAGE>   72

principal amount of Outstanding Securities and (ii) the Persons entitled to vote
not less than 66 2/3% in principal amount of Outstanding Securities represented
and entitled to vote at such meeting.

          Any resolution passed or decisions taken at any meeting of Holders of
Securities duly held in accordance with this Section shall be binding on all the
Holders of Securities whether or not present or represented at the meeting. The
Trustee shall, in the name and at the expense of the Company, notify all the
Holders of Securities of any such resolutions or decisions pursuant to Section
1.6.

          SECTION 9.5 DETERMINATION OF VOTING RIGHTS; CONDUCT AND ADJOURNMENT OF
MEETINGS.

          (1) Notwithstanding any other provisions of this Indenture, the
Trustee may make such reasonable regulations as it may deem advisable for any
meeting of Holders of Securities in regard to proof of the holding of Securities
and of the appointment of proxies and in regard to the appointment and duties of
inspectors of votes, the submission and examination of proxies, certificates and
other evidence of the right to vote, and such other matters concerning the
conduct of the meeting as it shall deem appropriate. Except as otherwise
permitted or required by any such regulations, the holding of Securities shall
be proved in the manner specified in Section 1.4 and the appointment of any
proxy shall be proved in the manner specified in Section 1.4 or by having the
signature of the Person executing the proxy guaranteed by any bank, broker or
other eligible institution participating in a recognized medallion signature
guarantee program.

          (2) The Trustee shall, by an instrument in writing, appoint a
temporary chairman (which may be the Trustee) of the meeting, unless the meeting
shall have been called by the Company or by Holders of Securities as provided in
Section 9.2(1), in which case the Company or the Holders of Securities calling
the meeting, as the case may be, shall in like manner appoint a temporary
chairman. A permanent chairman and a permanent secretary of the meeting shall be
elected by vote of the Persons entitled to vote a majority in principal amount
of the Outstanding Securities represented at the meeting.

          (3) At any meeting, each Holder of a Security or proxy shall be
entitled to one vote for each U.S. $1,000 principal amount of Securities held or
represented by him; provided, however, that no vote shall be cast or counted at
any meeting in respect of any Security challenged as not Outstanding and ruled
by the chairman of the meeting to be not Outstanding. The chairman of the
meeting shall have no right to vote, except as a Holder of a Security or proxy.

          (4) Any meeting of Holders of Securities duly called pursuant to
Section 9.2 at which a quorum is present may be adjourned from time to time by
Persons entitled to vote a majority in principal amount of the Outstanding
Securities represented at the meeting, and the meeting may be held as so
adjourned without further notice.

          SECTION 9.6 COUNTING VOTES AND RECORDING ACTION OF MEETINGS. The vote
upon any resolution submitted to any meeting of Holders of Securities shall be
by written ballots

                                       65
<PAGE>   73

on which shall be subscribed the signatures of the Holders of Securities or of
their representatives by proxy and the principal amounts at Stated Maturity and
serial numbers of the Outstanding Securities held or represented by them. The
permanent chairman of the meeting shall appoint two inspectors of votes who
shall count all votes cast at the meeting for or against any resolution and who
shall make and file with the secretary of the meeting their verified written
reports in duplicate of all votes cast at the meeting. A record, at least in
duplicate, of the proceedings of each meeting of Holders of Securities shall be
prepared by the secretary of the meeting and there shall be attached to said
record the original reports of the inspectors of votes on any vote by ballot
taken thereat and affidavits by one or more Persons having knowledge of the
facts setting forth a copy of the notice of the meeting and showing that said
notice was given as provided in Section 9.2 and, if applicable, Section 9.4.
Each copy shall be signed and verified by the affidavits of the permanent
chairman and secretary of the meeting and one such copy shall be delivered to
the Company and another to the Trustee to be preserved by the Trustee, the
latter to have attached thereto the ballots voted at the meeting. Any record so
signed and verified shall be conclusive evidence of the matters therein stated.

                                   ARTICLE X

                                   COVENANTS

          SECTION 10.1 PAYMENT OF PRINCIPAL, PREMIUM AND INTEREST. The Company
covenants and agrees that it will duly and punctually pay the principal of and
premium, if any, and interest on the Securities in accordance with the terms of
the Securities and this Indenture. The Company will deposit or cause to be
deposited with the Trustee, no later than the opening of business on the date of
the Stated Maturity of any Security or no later than the opening of business on
the due date for any installment of interest, all payments so due, which
payments shall be in immediately available funds on the date of such Stated
Maturity or due date, as the case may be.

          SECTION 10.2 MAINTENANCE OF OFFICES OR AGENCIES. The Company will
maintain in the Borough of Manhattan, The City of New York, an office or agency
where the Securities may be surrendered for registration of transfer or exchange
or for presentation for payment or for conversion, redemption or repurchase and
where notices and demands to or upon the Company in respect of the Securities
and this Indenture may be served. The Company will give prompt written notice to
the Trustee of the location, and any change in the location, of such office or
agency not designated or appointed by the Trustee. If at any time the Company
shall fail to maintain any such required office or agency or shall fail to
furnish the Trustee with the address thereof, such presentations, surrenders,
notices and demands may be made or served at the Corporate Trust Office or the
office or agency of the Trustee.

          The Company may at any time and from time to time vary or terminate
the appointment of any such agent or appoint any additional agents for any or
all of such purposes; provided, however, that until all of the Securities have
been delivered to the Trustee for cancellation, or moneys sufficient to pay the
principal of, premium, if any, and interest on the Securities have been made
available for payment and either paid or returned to the Company

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<PAGE>   74

pursuant to the provisions of Section 10.3, the Company will maintain in the
Borough of Manhattan, The City of New York, an office or agency where Securities
may be presented or surrendered for payment and conversion where Securities may
be surrendered for registration of transfer or exchange and where notices and
demands to or upon the Company in respect of the Securities and this Indenture
may be served. The Company will give prompt written notice to the Trustee, and
notice to the Holders in accordance with Section 1.6, of the appointment or
termination of any such agents and of the location and any change in the
location of any such office or agency.

          The Company hereby initially designates the Trustee as Paying Agent,
Security Registrar and Conversion Agent, and each of the Corporate Trust Office
of the Trustee and the office or agency of the Trustee located at Wilmington
Trust Company Drop Agent: Harris Trust Company of New York, 88 Pine Street -
19th Floor, Wall Street Plaza, New York, New York 10005 as one such office or
agency of the Company for each of the aforesaid purposes.

          SECTION 10.3 MONEY FOR SECURITY PAYMENTS TO BE HELD IN TRUST. If the
Company shall act as its own Paying Agent, it will, on or before each due date
of the principal of, premium, if any, or interest on any of the Securities,
segregate and hold in trust for the benefit of the Persons entitled thereto a
sum sufficient to pay the principal, 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 the Company will promptly notify the Trustee of its action
or failure so to act.

          Whenever the Company shall have one or more Paying Agents, it will, no
later than the opening of business on each due date of the principal of,
premium, if any, or interest on any Securities, deposit with the Trustee a sum
in funds immediately payable on the payment date sufficient to pay the
principal, premium, if any, or interest so becoming due, such sum to be held for
the benefit of the Persons entitled to such principal, premium, if any, or
interest, and (unless such Paying Agent is the Trustee) the Company will
promptly notify the Trustee of any 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:

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

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

          (3) at any time during the continuance of any such default, upon the
     written request of the Trustee, forthwith pay to the Trustee all sums so
     held 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

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<PAGE>   75

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

          Any money deposited with the Trustee or any Paying Agent, or then held
by the Company, in trust for the payment of the principal of, premium, if any,
or interest on any Security and remaining unclaimed for two years after such
principal, premium, if any, or interest has become due and payable shall be paid
to the Company on Company Request, or (if then held by the Company) shall be
discharged from such trust; and the Holder of such Security shall thereafter, as
an unsecured general creditor, look only to the Company for payment thereof, and
all liability of the Trustee or such Paying Agent with respect to such trust
money, and all liability of the Company as trustee thereof, shall thereupon
cease.

          SECTION 10.4 EXISTENCE. Subject to Article VII, the Company will do or
cause to be done all things necessary to preserve and keep in full force and
effect its existence, rights (charter and statutory) and franchises; provided,
however, that the Company shall not be required to preserve any such right or
franchise if the Company 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 10.5 MAINTENANCE OF PROPERTIES. The Company will cause all
properties used or useful in the conduct of its business or the business of any
Significant Subsidiary to be maintained and kept in good condition, repair and
working order and supplied with all necessary equipment and will cause to be
made all necessary repairs, renewals, replacements, betterments and improvements
thereof, all as in the judgment of the Company may be necessary so that the
business carried on in connection therewith may be properly and advantageously
conducted at all times; provided, however, that nothing in this Section shall
prevent the Company from discontinuing the operation or maintenance of any of
such properties if such discontinuance is, in the judgment of the Company,
desirable in the conduct of its business or the business of any Significant
Subsidiary and not disadvantageous in any material respect to the Holders.

          SECTION 10.6 PAYMENT OF TAXES AND OTHER CLAIMS. The Company will pay
or discharge, or cause to be paid or discharged, before the same may become
delinquent, (i) all taxes, assessments and governmental charges levied or
imposed upon the Company or any Significant Subsidiary or upon the income,
profits or property of the Company or any Significant Subsidiary, (ii) all
claims for labor, materials and supplies which, if unpaid, might by law become a
lien or charge upon the property of the Company or any Significant Subsidiary,
and (iii) all stamps and other duties, if any, which may be imposed by the
United States or any political subdivision thereof or therein in connection with
the issuance, transfer, exchange or conversion of any Securities or with respect
to this Indenture; provided, however, that, in the case of clauses (i) and (ii),
the Company shall not be required to pay or discharge or cause to be paid or
discharged any such tax, assessment, charge or claim (A) if the failure to do so
will not, in the aggregate, have a material adverse impact on the Company, or
(B) if the amount, applicability or validity is being contested in good faith by
appropriate proceedings.

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<PAGE>   76

          SECTION 10.7 STATEMENT BY OFFICERS AS TO DEFAULT. The Company shall
deliver to the Trustee, within 120 days after the end of each fiscal year of the
Company ending after the date hereof, an Officers' Certificate, stating whether
or not to the best knowledge of the signers thereof the Company is in default in
the performance and observance of any of the terms, provisions and conditions of
this Indenture (without regard to any period of grace or requirement of notice
provided hereunder) and, if the Company shall be in default, specifying all such
defaults and the nature and status thereof of which they may have knowledge.

          The Company will deliver to the Trustee, forthwith upon becoming aware
of any default or any Event of Default under the Indenture, an Officers'
Certificate specifying with particularity such default or Event of Default and
further stating what action the Company has taken, is taking or proposes to take
with respect thereto. 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.

          Any notice required to be given under this Section 10.8 shall be
delivered to the Trustee at its Corporate Trust Office.

          SECTION 10.8 WAIVER OF CERTAIN COVENANTS. The Company may omit in any
particular instance to comply with any covenant or condition set forth in
Sections 10.4 (other than with respect to the existence of the Company (subject
to Article VII)), 10.5 and 10.6, inclusive (other than a covenant or condition
which under Article VIII cannot be modified or amended without the consent of
the Holder of each Outstanding Security affected), if before the time for such
compliance the Holders shall, through (i) the written consent of not less than a
majority in principal amount of the Outstanding Securities, or (ii) the adoption
of a resolution at a meeting of Holders of the Outstanding Securities at which a
quorum is present, by the Holders of not less than 66 2/3% in principal amount
of the Outstanding Securities represented at such meeting, 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
or any Paying or Conversion Agent in respect of any such covenant or condition
shall remain in full force and effect.

                                   ARTICLE XI

                            REDEMPTION OF SECURITIES

          SECTION 11.1 RIGHT OF REDEMPTION. The Securities may be redeemed in
accordance with the provisions of the form of Securities set forth in Section
2.2.

          SECTION 11.2 APPLICABILITY OF ARTICLE. Redemption of Securities at the
election of the Company or otherwise, as permitted or required by any provision
of the Securities or this Indenture, shall be made in accordance with such
provision and this Article XI.

          SECTION 11.3 ELECTION TO REDEEM; NOTICE TO TRUSTEE. The election of
the Company to redeem any Securities shall be evidenced by a Board Resolution.
In case of any

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<PAGE>   77

redemption at the election of the Company of any of the Securities, the Company
shall, at least 60 days prior to the Redemption Date fixed by the Company
(unless a shorter notice shall be satisfactory to the Trustee), notify the
Trustee in writing of such Redemption Date.

          SECTION 11.4 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 by the Trustee after it receives the notice described
in 11.3, from the Outstanding Securities not previously called for redemption,
by lot or by such other method as the Trustee may 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 (so
far as may be) to be the portion selected for redemption. 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. The Trustee shall
promptly notify the Company and each Security Registrar in writing of the
securities selected for redemption and, in the case of any Securities selected
for partial redemption, the principal amount thereof to be redeemed.

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

          SECTION 11.5 NOTICE OF REDEMPTION. Notice of redemption shall be given
in the manner provided in Section 1.6 to the Holders of Securities to be
redeemed not less than 30 nor more than 60 days prior to the Redemption Date,
and such notice shall be irrevocable. The Company shall, concurrently with the
giving of such notice, publish a Press Release including the information
required to be included in such notice of redemption hereunder.

          All notices of redemption shall state:

          (1) the Redemption Date,

          (2) the Redemption Price, and accrued interest, if any, to the
     Redemption Date,

          (3) if less than all Outstanding Securities are to be redeemed, the
     aggregate principal amount of Securities to be redeemed and the aggregate
     principal amount of Securities which will be outstanding after such partial
     redemption,

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

          (5) the Conversion Rate, the date on which the right to convert the
     Securities to be redeemed will terminate and the places where such
     Securities may be surrendered for conversion, and

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<PAGE>   78

          (6) the place or places where such Securities are to be surrendered
     for payment of the Redemption Price and accrued interest, if any, to the
     Redemption Date.

          In case of a partial redemption, the notice shall specify the serial
and CUSIP numbers (if any) and the portions thereof called for redemption and
that transfers and exchanges may occur on or prior to the Redemption Date.

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

          SECTION 11.6 DEPOSIT OF REDEMPTION PRICE. On or prior to the
Redemption Date, the Company shall deposit with the Trustee (or, if the Company
is acting as its own Paying Agent, segregate and hold in trust as provided in
Section 10.3) an amount of money (which shall be in immediately available funds
on such Redemption Date) sufficient to pay the Redemption Price of, and (except
if the Redemption Date shall be an Interest Payment Date) accrued interest to
the Redemption Date on, all the Securities which are to be redeemed on that date
other than any Securities called for redemption on that date which have been
converted prior to the date of such deposit.

          If any Security called for redemption is converted, any money
deposited with the Trustee or so segregated and held in trust for the redemption
of such Security shall (subject to any right of the Holder of such Security or
any Predecessor Security to receive interest as provided in the last paragraph
of Section 3.9) be paid to the Company on Company Request or, if then held by
the Company, shall be discharged from such trust.

          SECTION 11.7 SECURITIES PAYABLE ON REDEMPTION DATE. Notice of
redemption having been given as aforesaid, the Securities so to be redeemed
shall, on the Redemption Date, become due and payable at the Redemption Price
therein specified and from and after such date (unless the Company shall default
in the payment of the Redemption Price, including accrued interest) such
Securities shall cease to bear interest. Upon surrender of any Security for
redemption in accordance with said notice such Security shall be paid by the
Company at the Redemption Price together with accrued and unpaid interest to the
Redemption Date; provided, however, that installments of interest on Securities
whose Stated Maturity is on or prior to the Redemption Date shall be payable to
the Holders of such Securities, or one or more Predecessor Securities,
registered as such on the relevant Record Date according to their terms and the
provisions of Section 3.9.

          If any Security called for redemption shall not be so paid upon
surrender thereof for redemption, the principal amount of, premium, if any, and,
to the extent permitted by applicable law, accrued interest on such Security
shall, until paid, bear interest from the Redemption Date at a rate of 7.50 %
per annum and such Security shall remain convertible until the Redemption Price
of such Security (or portion thereof, as the case may be) shall have been paid
or duly provided for.

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<PAGE>   79

          Any Security which is to be redeemed only in part shall be surrendered
at the Corporate Trust Office or an office or agency of the Company designated
for that purpose pursuant to Section 10.2 (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 make available for delivery to the Holder of
such Security without service charge, a new Security or Securities, of any
authorized denomination as requested by such Holder, in aggregate principal
amount equal to and in exchange for the unredeemed portion of the principal of
the Security so surrendered.

          SECTION 11.8 CONVERSION ARRANGEMENT ON CALL FOR REDEMPTION. In
connection with any redemption of Securities, the Company may arrange for the
purchase and conversion of any Securities by an agreement with one or more
investment bankers or other purchasers (the "Purchasers") to purchase such
securities by paying to the Trustee in trust for the Holders, on or before the
Redemption Date, an amount not less than the applicable Redemption Price,
together with interest accrued to the Redemption Date, of such Securities.
Notwithstanding anything to the contrary contained in this Article XI, the
obligation of the Company to pay the Redemption Price, together with interest
accrued to the Redemption Date, shall be deemed to be satisfied and discharged
to the extent such amount is so paid by such Purchasers. If such an agreement is
entered into (a copy of which shall be filed with the Trustee prior to the close
of business on the Business Day immediately prior to the Redemption Date), any
Securities called for redemption that are not duly surrendered for conversion by
the Holders thereof may, at the option of the Company, be deemed, to the fullest
extent permitted by law, and consistent with any agreement or agreements with
such Purchasers, to be acquired by such Purchasers from such Holders and
(notwithstanding anything to the contrary contained in Article XII) surrendered
by such Purchasers for conversion, all as of immediately prior to the close of
business on the Redemption Date (and the right to convert any such Securities
shall be extended through such time), subject to payment of the above amount as
aforesaid. At the direction of the Company, the Trustee shall hold and dispose
of any such amount paid to it by the Purchasers to the Holders in the same
manner as it would monies deposited with it by the Company for the redemption of
Securities. Without the Trustee's prior written consent, no arrangement between
the Company and such Purchasers for the purchase and conversion of any
Securities shall increase or otherwise affect any of the powers, duties,
responsibilities or obligations of the Trustee as set forth in this Indenture,
and the Company agrees to indemnify the Trustee from, and hold it harmless
against, any loss, liability or expense arising out of or in connection with any
such arrangement for the purchase and conversion of any Securities between the
Company and such Purchasers, including the costs and expenses, including
reasonable legal fees, incurred by the Trustee in the defense of any claim or
liability arising out of or in connection with the exercise or performance of
any of its powers, duties, responsibilities or obligations under this Indenture.

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                                  ARTICLE XII

                            CONVERSION OF SECURITIES

          SECTION 12.1 CONVERSION PRIVILEGE AND CONVERSION RATE. Subject to and
upon compliance with the provisions of this Article, at the option of the Holder
thereof, any Security may be converted into fully paid and nonassessable shares
(calculated as to each conversion to the nearest 1/100th of a share) of Common
Stock of the Company at the Conversion Rate, determined as hereinafter provided,
in effect at the time of conversion. Such conversion right shall commence on the
initial issuance date of the Securities and expire at the close of business on
the date of Maturity, subject, in the case of conversion of any Global Security,
to any Applicable Procedures. In case a Security or portion thereof is called
for redemption at the election of the Company or the Holder thereof exercises
his right to require the Company to repurchase the Security, such conversion
right in respect of the Security, or portion thereof so called, shall expire at
the close of business on the Business Day immediately preceding the Redemption
Date or the Repurchase Date, as the case may be, unless the Company defaults in
making the payment due upon redemption or repurchase, as the case may be (in
each case subject as aforesaid to any Applicable Procedures with respect to any
Global Security).

          The rate at which shares of Common Stock shall be delivered upon
conversion (herein called the "Conversion Rate") shall be initially 65.0618
shares of Common Stock for each U.S.$1,000 principal amount of Securities. The
Conversion Rate shall be adjusted in certain instances as provided in this
Article XII.

          SECTION 12.2 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 in blank, at any office or agency of the
Company maintained for that purpose pursuant to Section 10.2, accompanied by a
duly signed conversion notice substantially in the form set forth in Section 2.4
stating 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. Each Security surrendered for conversion (in whole or in part) during
the Record Date Period shall (except in the case of any Security or portion
thereof which has been called for redemption on a Redemption Date, or is
repurchasable on a Repurchase Date, occurring, in either case, within such
Record Date Period and, as a result, the right to convert such Security would
otherwise terminate in such period if not exercised) be accompanied by payment
in New York Clearing House 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 of such Security (or part thereof, as the case may be) being
surrendered for conversion. The interest so payable on such Interest Payment
Date with respect to any Security (or portion thereof, if applicable) which is
surrendered for conversion during the Record Date Period shall be paid to the
Holder of such Security as of such Regular Record Date in an amount equal to the
interest that would have been payable on such Security if such Security had been
converted as of the close of business on such Interest Payment Date. Interest
payable on any Interest Payment Date in respect of any Security surrendered for
conversion on or after such Interest Payment Date shall be paid to the Holder of
such Security as of the Regular Record Date next preceding such Interest Payment
Date, notwithstanding the exercise of the right of conversion. Except as
provided in this paragraph and subject to the last

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<PAGE>   81

paragraph of Section 3.9, no cash payment or adjustment shall be made upon any
conversion on account of any interest accrued from the Interest Payment Date
next preceding the conversion date, in respect of any Security (or part thereof,
as the case may be) surrendered for conversion, or on account of any dividends
on the Common Stock issued upon conversion. The Company's delivery to the Holder
of the number of shares of Common Stock (and cash in lieu of fractions thereof,
as provided in this Indenture) into which a Security is convertible will be
deemed to satisfy the Company's obligation to pay the principal amount of the
Security.

          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, 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, the Company
shall issue and deliver to the Trustee, for delivery to the Holder, 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 12.3.

          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 an aggregate principal amount equal to
the unconverted portion of the principal amount of such Security. A Security may
be converted in part, but only if the principal amount of such Security to be
converted is any integral multiple of U.S. $1,000 and the principal amount of
such security to remain Outstanding after such conversion is equal to U.S.
$1,000 or any integral multiple of $1,000 in excess thereof.

          SECTION 12.3 FRACTIONS OF SHARES. No fractional shares of Common Stock
shall be issued upon conversion of any Security or 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 Securities (or specified portions thereof), the Company shall calculate and
pay a cash adjustment in respect of such fraction (calculated to the nearest
1/100th of a share) in an amount equal to the same fraction of the Closing Price
Per Share at the close of business on the day of conversion.

          SECTION 12.4 ADJUSTMENT OF CONVERSION RATE. The Conversion Rate shall
be subject to adjustments from time to time as follows:

          (1) In case the Company shall pay or make a dividend or other
     distribution on shares of any class of capital stock payable in shares of
     Common Stock, the Conversion Rate in effect at the opening of business on
     the day following the date fixed for the determination of shareholders
     entitled to receive such dividend or other distribution shall be increased
     by dividing such Conversion Rate 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

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<PAGE>   82

     of shares and the total number of shares constituting such dividend or
     other distribution, such increase to become effective immediately after the
     opening of business on the day following the date fixed for such
     determination. If, after any such date fixed for determination, any
     dividend or distribution is not in fact paid, the Conversion Rate shall be
     immediately readjusted, effective as of the date the Board of Directors
     determines not to pay such dividend or distribution, to the Conversion Rate
     that would have been in effect if such determination date had not been
     fixed. For the purposes of this paragraph (1), 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 will not pay any dividend or make any distribution on shares of
     Common Stock held in the treasury of the Company.

          (2) In case the Company shall issue rights, options or warrants to all
     holders of its Common Stock entitling them 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 paragraph (8) of this Section
     12.4) of the Common Stock on the date fixed for the determination of
     stockholders entitled to receive such rights, options or warrants (other
     than any rights, options or warrants that by their terms will also be
     issued to any Holder upon conversion of a Security into shares of Common
     Stock without any action required by the Company or any other Person), the
     Conversion Rate in effect at the opening of business on the day following
     the date fixed for such determination shall be increased by dividing such
     Conversion Rate 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 increase to become effective immediately
     after the opening of business on the day following the date fixed for such
     determination. If, after any such date fixed for determination, any such
     rights, options or warrants are not in fact issued, or are not exercised
     prior to the expiration thereof, the Conversion Rate shall be immediately
     readjusted, effective as of the date such rights, options or warrants
     expire, or the date the Board of Directors determines not to issue such
     rights, options or warrants, to the Conversion Rate that would have been in
     effect if the unexercised rights, options or warrants had never been
     granted or such determination date had not been fixed, as the case may be.
     For the purposes of this paragraph (2), 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 will not issue any rights, options or warrants in respect of shares
     of Common Stock held in the treasury of the Company.

          (3) In case outstanding shares of Common Stock shall be subdivided
     into a greater number of shares of Common Stock, the Conversion Rate in
     effect at the opening of business on the day following the day upon which
     such subdivision becomes effective shall be proportionately increased, and,
     conversely, in case outstanding shares of

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<PAGE>   83

     Common Stock shall be combined into a smaller number of shares of Common
     Stock, the Conversion Rate in effect at the opening of business on the day
     following the day upon which such subdivision or combination becomes
     effective shall be proportionately reduced, such increase or reduction, 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.

          (4) 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 or other property (including cash or assets or
     securities, but excluding (i) any rights, options or warrants referred to
     in paragraph (2) of this Section, (ii) any dividend or distribution paid
     exclusively in cash, (iii) any dividend or distribution referred to in
     paragraph (1) of this Section and (iv) any consideration distributed in any
     merger or consolidation to which Section 12.11 applies), the Conversion
     Rate shall be adjusted so that the same shall equal the rate determined by
     dividing the Conversion Rate in effect immediately prior to the close of
     business on the date fixed for the determination of stockholders entitled
     to receive such distribution by a fraction of which the numerator shall be
     the current market price per share (determined as provided in paragraph (8)
     of this Section 12.4) of the Common Stock on the date fixed for such
     determination less the then fair market value (as determined by the Board
     of directors, whose determination shall be conclusive and described in a
     Board Resolution filed with the Trustee) of the portion of the assets,
     shares or evidences of indebtedness 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 adjustment to become effective immediately
     prior to the opening of business on the day following the date fixed for
     the determination of stockholders entitled to receive such distribution. If
     after any such date fixed for determination, any such distribution is not
     in fact made, the Conversion Rate shall be immediately readjusted,
     effective as of the date of the Board of Directors determines not to make
     such distribution, to the Conversion Rate that would have been in effect if
     such determination date had not been fixed.

          (5) In case the Company shall, by dividend or otherwise, distribute to
     all holders of its Common Stock cash (excluding any cash that is
     distributed as part of a distribution referred to in paragraph (4) of this
     Section or cash distributed upon a merger or consolidation to which Section
     12.11 applies) in an aggregate amount that, combined together with (I) the
     aggregate amount of any other all-cash distributions to all holders of its
     Common Stock made exclusively in cash within the 365-day period preceding
     the date of payment of such distribution and in respect of which no
     adjustment pursuant to this paragraph (5) has been made and (II) the
     aggregate of any cash plus the fair market value (as determined by the
     Board of Directors, whose determination shall be conclusive and described
     in a Board Resolution) of consideration payable in respect of any tender
     offer by the Company or any of its Subsidiaries for all or any portion of
     the Common Stock concluded within the 365-day period preceding the date of
     payment of such distribution and in respect of which no adjustment pursuant
     to paragraph (6) of this Section 12.4 has been made (the "combined cash and
     tender amount") exceeds 10% of the product of the current market price per
     share (determined as provided in paragraph (8) of this Section 12.4) of the
     Common Stock on the date for the determination of holders of shares of
     Common Stock entitled to receive such distribution times the number of
     shares of

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<PAGE>   84

     Common Stock outstanding on such date (the "aggregate current market
     price"), then, and in each such case, immediately after the close of
     business on such date for determination, the Conversion Rate shall be
     adjusted so that the same shall equal the rate determined by dividing the
     Conversion Rate in effect immediately prior to the close of business on the
     date fixed for determination of the stockholders entitled to receive such
     distribution by a fraction (i) the numerator of which shall be equal to the
     current market price per share (determined as provided in paragraph (8) of
     this Section) of the Common Stock on the date fixed for such determination
     less an amount equal to the quotient of (x) the excess of such combined
     cash and tender amount over 10% of such aggregate current market price
     divided by (y) the number of shares of Common Stock outstanding on such
     date for determination and (ii) the denominator of which shall be equal to
     the current market price per share (determined as provided in paragraph (8)
     of this Section 12.4) of the Common Stock on such date fixed for
     determination.

          (6) In case a tender offer made by the Company or any Subsidiary for
     all or any portion of the Common Stock shall expire and such tender offer
     (as amended upon the expiration thereof) shall require the payment to
     stockholders (based on the acceptance (up to any maximum specified in the
     terms of the tender offer) of Purchased Shares (as defined below)) of an
     aggregate consideration having a fair market value (as determined by the
     Board of Directors, whose determination shall be conclusive and described
     in a Board Resolution) that combined together with (I) the aggregate of the
     cash plus the fair market value (as determined by the Board of Directors,
     whose determination shall be conclusive and described in a Board
     Resolution), as of the expiration of such tender offer, of consideration
     payable in respect of any other tender offer by the Company or any
     Subsidiary for all or any portion of the Common Stock expiring within the
     365-day period preceding the expiration of such tender offer and in respect
     of which no adjustment pursuant to this paragraph (6) has been made and
     (II) the aggregate amount of any cash distributions to all holders of the
     Common Stock within 365-day period preceding the expiration of such tender
     offer and in respect of which no adjustment pursuant to paragraph (5) of
     this Section has been made (the "combined tender and cash amount") exceeds
     10% of the product of the current market price per share of the Common
     Stock (determined as provided in paragraph (8) of this Section 12.4) as of
     the last time (the "Expiration Time") tenders could have been made pursuant
     to such tender offer (as it may be amended) times the number of shares of
     Common Stock outstanding (including any tendered shares) as of the
     Expiration Time, then, and in each such case immediately prior to the
     opening of business on the day after the date of the Expiration Time, the
     Conversion Rate shall be adjusted so that the same shall equal the rate
     determined by dividing the Conversion Rate immediately prior to close of
     business on the date of the Expiration Time by a fraction (i) the numerator
     of which shall be equal to (A) the product of (I) the current market price
     per share of the Common Stock (determined as provided in paragraph (8) of
     this Section 12.4) on the date of the Expiration Time multiplied by (II)
     the number of shares of Common Stock outstanding (including any tendered
     shares) on the Expiration Time less (B) the combined tender and cash
     amount, and (ii) the denominator of which shall be equal to the product of
     (A) the current market price per share of the Common Stock (determined as
     provided in paragraph (8) of this Section 12.4) as of the Expiration Time
     multiplied by (B) the number of shares of Common Stock outstanding
     (including any tendered shares) as of the Expiration Time

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<PAGE>   85

     less the number of all shares validly tendered 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").

          (7) The reclassification of Common Stock into securities other than
     Common Stock (other than any reclassification upon a consolidation or
     merger to which Section 12.11 applies) shall be deemed to involve (a) a
     distribution of such securities other than Common Stock to all holders of
     Common Stock (and the effective date of such reclassification shall be
     deemed to be "the date fixed for the determination of stockholders entitled
     to receive such distribution" and "the date fixed for such determination"
     within the meaning of paragraph (4) of this Section), and (b) a subdivision
     or combination, as the case may be, of the number of shares of Common Stock
     outstanding immediately prior to such reclassification into the number of
     shares of Common Stock outstanding immediately thereafter (and the
     effective date of such reclassification shall be deemed to be "the day upon
     which such subdivision becomes effective" or "the day upon which such
     combination becomes effective", as the case may be, and "the day upon which
     such subdivision or combination becomes effective" within the meaning of
     paragraph (3) of this Section 12.4).

          (8) For the purpose of any computation under paragraphs (2), (4), (5)
     or (6) of this Section 12.4, the current market price per share of Common
     Stock on any date shall be calculated by the Company and be the average of
     the daily Closing Prices Per Share for the five consecutive Trading Days
     selected by the Company commencing not more than 10 Trading Days before,
     and ending not later than the earlier of the day in question and the day
     before the "ex" date with respect to the issuance or distribution requiring
     such computation. For purposes of this paragraph, the term "'ex' date",
     when used with respect to any issuance or distribution, means the first
     date on which the Common Stock trades regular way in the applicable
     securities market or on the applicable securities exchange without the
     right to receive such issuance or distribution.

          (9) No adjustment in the Conversion Rate shall be required unless such
     adjustment (plus any adjustments not previously made by reason of this
     paragraph (9)) would require an increase or decrease of at least one
     percent in such rate; provided, however, that any adjustments which by
     reason of this paragraph (9) are not required to be made shall be carried
     forward and taken into account in any subsequent adjustment. All
     calculations under this Article shall be made to the nearest cent or to the
     nearest one-hundredth of a share, as the case may be.

          (10) The Company may make such increases in the Conversion Rate, for
     the remaining term of the Securities or any shorter term, in addition to
     those required by paragraphs (1), (2), (3), (4), (5) and (6) of this
     Section 12.4, as it considers to be advisable in order to avoid or diminish
     any income tax to any holders of shares of Common Stock resulting from any
     dividend or distribution of stock or issuance of rights or warrants to
     purchase or subscribe for stock or from any event treated as such for
     income tax purposes. The Company shall have the power to resolve any
     ambiguity or correct any error in this paragraph (10) and its actions in so
     doing shall, absent manifest error, be final and conclusive.

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<PAGE>   86

          (11) Notwithstanding the foregoing provisions of this Section, no
     adjustment of the Conversion Rate shall be required to be made (a) upon the
     issuance of shares of Common Stock pursuant to any present or future plan
     for the reinvestment of dividends or (b) because of a tender or exchange
     offer of the character described in Rule 13e-4(h)(5) under the Exchange Act
     or any successor rule thereto.

          (12) To the extent permitted by applicable law, the Company from time
     to time may increase the Conversion Rate by any amount for any period of
     time if the period is at least twenty (20) days, the increase is
     irrevocable during such period, and the Board of Directors shall have made
     a determination that such increase would be in the best interests of the
     Company, which determination shall be conclusive; provided, however, that
     no such increase shall be taken into account for purposes of determining
     whether the Closing Price Per Share of the Common Stock equals or exceeds
     105% of the Conversion Price in connection with an event which would
     otherwise be a Change of Control pursuant to Section 14.4. Whenever the
     Conversion Rate is increased pursuant to the preceding sentence, the
     Company shall give notice of the increase to the Holders in the manner
     provided in Section 1.6 at least fifteen (15) days prior to the date the
     increased Conversion Rate takes effect, and such notice shall state the
     increased Conversion Rate and the period during which it will be in effect.

          SECTION 12.5 NOTICE OF ADJUSTMENTS OF CONVERSION RATE. Whenever the
Conversion Rate is adjusted as herein provided:

          (1) the Company shall compute the adjusted Conversion Rate in
     accordance with Section 12.4 and shall prepare a certificate signed by the
     Chief Financial Officer of the Company setting forth the adjusted
     Conversion Rate and showing in reasonable detail the facts upon which such
     adjustment is based, and such certificate shall promptly be filed with the
     Trustee and with each Conversion Agent; and

          (2) upon each such adjustment, a notice stating that the Conversion
     Rate has been adjusted and setting forth the adjusted Conversion Rate shall
     be required, and as soon as practicable after it is required, such notice
     shall be provided by the Company to all Holders in accordance with Section
     1.6.

          Neither the Trustee nor any Conversion Agent shall be under any duty
or responsibility with respect to any such certificate or the information and
calculations contained therein, except to exhibit the same to any Holder of
Securities desiring inspection thereof at its office during normal business
hours, and shall not be deemed to have knowledge of any adjustment in the
Conversion Rate unless and until a Responsible Officer of the Trustee shall have
received such a certificate. Until a Responsible Officer of the Trustee receives
such a certificate, the Trustee and each Conversion Agent may assume without
inquiry that the last Conversion Rate of which the Trustee has knowledge of
remains in effect.

          SECTION 12.6 NOTICE OF CERTAIN CORPORATE ACTION. In case:

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<PAGE>   87

          (1) the Company shall declare a dividend (or any other distribution)
     on its Common Stock payable (i) otherwise than exclusively in cash or (ii)
     exclusively in cash in an amount that would require any adjustment pursuant
     to Section 12.4; or

          (2) the Company shall authorize the granting to all or substantially
     all of the holders of its Common Stock of rights, options or warrants to
     subscribe for or purchase any shares of capital stock of any class or of
     any other rights; or

          (3) of any reclassification of the Common Stock, or of any
     consolidation, merger or share exchange to which the Company is a party and
     for which approval of any stockholders of the Company is required, or of
     the conveyance, sale, transfer or lease of all or substantially all of the
     assets of the Company; or

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

then the Company shall cause to be filed at each office or agency maintained for
the purpose of conversion of Securities pursuant to Section 10.2, and shall
cause to be provided to all Holders in accordance with Section 1.6, at least 20
days (or 10 days in any case specified in clause (1) or (2) above) prior to the
applicable record or effective date hereinafter specified, a notice stating (x)
the date on which a record is to be taken for the purpose of such dividend,
distribution, rights, options or warrants, 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, options or warrants are to be determined or
(y) the date on which such reclassification, consolidation, merger, conveyance,
transfer, sale, lease, 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, conveyance, transfer, sale, lease, dissolution,
liquidation or winding up. Neither the failure to give such notice or the notice
referred to in the following paragraph nor any defect therein shall affect the
legality or validity of the proceedings described in clauses (1) through (4) of
this Section 12.6. If at the time the Trustee shall not be the conversion agent,
a copy of such notice shall also forthwith be filed by the Company with the
Trustee.

          The Company shall cause to be filed at the Corporate Trust Office and
each office or agency maintained for the purpose of conversion of Securities
pursuant to Section 10.2, and shall cause to be provided to all Holders in
accordance with Section 1.6, notice of any tender offer by the Company or any
Subsidiary for all or any portion of the Common Stock at or about the time that
such notice of tender offer is provided to the public generally.

          SECTION 12.7 COMPANY TO RESERVE COMMON STOCK. The Company shall at all
times reserve and keep available, free from preemptive rights, out of its
authorized but unissued Common Stock, for the purpose of effecting the
conversion of Securities, the full number of shares of Common Stock then
issuable upon the conversion of all Outstanding Securities.

          SECTION 12.8 TAXES ON CONVERSIONS. Except as provided in the next
sentence, the Company will pay any and all taxes and duties that may be payable
in respect of the issue or

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<PAGE>   88

delivery of shares of Common Stock on conversion of Securities pursuant hereto.
The Company shall not, however, be required to pay any tax or duty 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 duty, or has established to the satisfaction of the Company that
such tax or duty has been paid.

          SECTION 12.9 COVENANT AS TO COMMON STOCK. The Company agrees that all
shares of Common Stock which may be delivered upon conversion of Securities,
upon such delivery, will have been duly authorized and validly issued and will
be fully paid and nonassessable and, except as provided in Section 12.8, the
Company will pay all taxes, liens and charges with respect to the issue thereof.

          SECTION 12.10 CANCELLATION OF CONVERTED SECURITIES. All Securities
delivered for conversion shall be delivered to the Trustee or its agent to be
canceled by or at the direction of the Trustee, which shall dispose of the same
as provided in Section 3.11.

          SECTION 12.11 PROVISION IN CASE OF CONSOLIDATION, MERGER OR SALE OF
ASSETS. In case of any consolidation or merger of the Company with or into any
other Person, any merger of another Person with or into the Company (other than
a merger which does not result in any reclassification, conversion, exchange or
cancellation of outstanding shares of Common Stock of the Company) or any
conveyance, sale, transfer or lease of all or substantially all of the assets of
the Company, the Person formed by such consolidation or resulting from such
merger or which acquires such assets, as the case may be, shall execute and
deliver to the Trustee a supplemental indenture providing that the Holder of
each Security then Outstanding shall have the right thereafter, during the
period such Security shall be convertible as specified in Section 12.1, to
convert such Security only into the kind and amount of securities, cash and
other property receivable upon such consolidation, merger, conveyance, sale,
transfer or lease by a holder of the number of shares of Common Stock of the
Company into which such Security might have been converted immediately prior to
such consolidation, merger, conveyance, sale, transfer or lease, assuming such
holder of Common Stock of the Company (i) is not (A) a Person with which the
Company consolidated or merged with or into or which merged into or with the
Company or to which such conveyance, sale, transfer or lease was made, as the
case may be (a "Constituent Person"), or (B) an Affiliate of a Constituent
Person and (ii) failed to exercise his rights of election, if any, as to the
kind or amount of securities, cash and other property receivable upon such
consolidation, merger, conveyance, sale, transfer or lease (provided that if the
kind or amount of securities, cash and other property receivable upon such
consolidation, merger, conveyance, sale, transfer, or lease is not the same for
each share of Common Stock of the Company held immediately prior to such
consolidation, merger, conveyance, sale, transfer or lease by others than a
Constituent Person or an Affiliate thereof and in respect of which such rights
of election shall not have been exercised ("Non-electing Share"), then for the
purpose of this Section 12.11 the kind and amount of securities, cash and other
property receivable upon such consolidation, merger, conveyance, sale, transfer
or lease by the holders of each Non-electing Share shall be deemed to be the
kind and amount so receivable per share by a plurality of the Non-electing
Shares). Such supplemental indenture shall provide for adjustments which, for
events subsequent to the effective date of such supplemental indenture, shall be
as nearly

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<PAGE>   89

equivalent as may be practicable to the adjustments provided for in this
Article. The above provisions of this Section 12.11 shall similarly apply to
successive consolidations, mergers, conveyances, sales, transfers or leases.
Notice of the execution of such a supplemental indenture shall be given by the
Company to the Holder of each Security as provided in Section 1.6 promptly upon
such execution.

          Neither the Trustee nor any Conversion Agent shall be under any
responsibility to determine the correctness of any provisions contained in any
such supplemental indenture relating either to the kind or amount of shares of
stock or other securities or property or cash receivable by Holders of
Securities upon the conversion of their Securities after any such consolidation,
merger, conveyance, transfer, sale or lease or to any such adjustment, but may
accept as conclusive evidence of the correctness of any such provisions, and
shall be protected in relying upon, an Opinion of Counsel with respect thereto,
which the Company shall cause to be furnished to the Trustee upon request.

          SECTION 12.12 RIGHTS ISSUED IN RESPECT OF COMMON STOCK. Rights or
warrants distributed by the Company to all holders of Common Stock entitling the
holders thereof to subscribe for or purchase shares of the Company's capital
stock (either initially or under certain circumstances), which rights or
warrants, until the occurrence of a specified event or events ("Trigger Event"):

          (1) are deemed to be transferred with such shares of Common Stock,

          (2) are not exercisable, and

          (3) are also issued in respect of future issuances of Common Stock

shall not be deemed distributed for purposes of Section 12.4(2) until the
occurrence of the earliest Trigger Event. In addition, in the event of any
distribution of rights or warrants, or any Trigger Event with respect thereto,
that shall have resulted in an adjustment to the Conversion Rate under Section
12.4(2), (1) in the case of any such rights or warrants which shall all have
been redeemed or repurchased without exercise by any holders thereof, the
Conversion Rate shall be readjusted upon such final redemption or repurchase to
give effect to such distribution or Trigger Event, as the case may be, as though
it were a cash distribution, equal to the per share redemption or repurchase
price received by a holder of Common Stock with respect to such rights or
warrants (assuming such holder had retained such rights or warrants), made to
all holders of Common Stock as of the date of such redemption or repurchase, and
(2) in the case of any such rights or warrants all of which shall have expired
without exercise by any holder thereof, the Conversion Price shall be readjusted
as if such issuance had not occurred.

          SECTION 12.13 RESPONSIBILITY OF TRUSTEE FOR CONVERSION PROVISIONS. The
Trustee, subject to the provisions of Section 6.1, and any Conversion Agent
shall not at any time be under any duty or responsibility to any Holder of
Securities to determine whether any facts exist which may require any adjustment
of the Conversion Rate, or with respect to the nature or extent of any such
adjustment when made, or with respect to the method employed, herein or in any
supplemental indenture provided to be employed, in making the same, or whether a
supplemental indenture need be entered into. Neither the Trustee, subject to the
provisions of

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<PAGE>   90

Section 6.1, nor any Conversion Agent shall be accountable with respect to the
validity or value (or the kind or amount) of any Common Stock, or of any other
securities or property or cash, which may at any time be issued or delivered
upon the conversion of any Security; and it or they do not make any
representation with respect thereto. Neither the Trustee, subject to the
provisions of Section 6.1, nor any Conversion Agent shall be responsible for any
failure of the Company to make or calculate any cash payment or to issue,
transfer or deliver any shares of Common Stock or share certificates or other
securities or property or cash upon the surrender of any Security for the
purpose of conversion; and the Trustee, subject to the provisions of Section
6.1, and any Conversion Agent shall not be responsible for any failure of the
Company to comply with any of the covenants of the Company contained in this
Article.

                                  ARTICLE XIII

                           SUBORDINATION OF SECURITIES

          SECTION 13.1 SECURITIES SUBORDINATE TO SENIOR DEBT. The Company
covenants and agrees, and each Holder of a Security, by its acceptance thereof,
likewise covenants and agrees, that, to the extent and in the manner hereinafter
set forth in this Article (subject to the provisions of Article IV), the
indebtedness represented by the Securities and the payment of the principal of,
or premium, if any, or interest on, each and all of the Securities (including,
but not limited to, the Redemption Price with respect to the Securities to be
called for redemption in accordance with Article XI or the Repurchase Price with
respect to Securities submitted for repurchase in accordance with Article XIV),
are hereby expressly made subordinate and subject in right of payment to the
prior payment in full of all Senior Debt.

          SECTION 13.2 NO PAYMENT IN CERTAIN CIRCUMSTANCES, PAYMENT OVER OF
PROCEEDS UPON DISSOLUTION, ETC. No payment shall be made with respect to the
principal of, or premium, if any, or interest on the Securities (including, but
not limited to, the Redemption Price with respect to the Securities to be called
for redemption in accordance with Article XI or the Repurchase Price with
respect to Securities submitted for repurchase in accordance with Article XIV),
except payments and distributions made by the Trustee as permitted by Section
13.9, if:

          (1) a default in the payment of principal, premium, if any, or
     interest (including a default under any repurchase or redemption
     obligation) or other amounts with respect to any Senior Debt occurs and is
     continuing (or, in the case of Senior Debt for which there is a period of
     grace, in the event of such a default that continues beyond the period of
     grace, if any, specified in the instrument or lease evidencing such Senior
     Debt) unless and until such default shall have been cured or waived or
     shall have ceased to exist; or

          (2) any other event of default occurs and is continuing with respect
     to Designated Senior Debt that then permits holders of such Designated
     Senior Debt to accelerate its maturity and the Trustee receives a notice of
     the default (a "Payment Blockage Notice") from a Representative or holder
     of Designated Senior Debt or the Company.

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<PAGE>   91

          If the Trustee receives any Payment Blockage Notice pursuant to clause
(ii) above, no subsequent Payment Blockage Notice shall be effective for
purposes of this Section unless and until (A) at least 365 days shall have
elapsed since the initial effectiveness of the immediately prior Payment
Blockage Notice, and (B) all scheduled payments of principal, premium, if any,
and interest on the Securities that have come due have been paid in full in
cash. No nonpayment default that existed or was continuing on the date of
delivery of any Payment Blockage Notice to the Trustee shall be, or be made, the
basis for a subsequent Payment Blockage Notice.

          The Company may and shall resume payments on and distributions in
respect of the Securities upon the earlier of:

          (1) in the case of a default referred to in clause (i) above, the date
     upon which the default is cured or waived or ceases to exist, or

          (2) in the case of a default referred to in clause (ii) above, the
     date upon which the default is cured or waived or ceases to exist or 179
     days pass after notice is received if the maturity of such Designated
     Senior Debt has not been accelerated, unless this Article XIII otherwise
     prohibits the payment or distribution at the time of such payment or
     distribution.

          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 Debt shall be entitled to receive payment in
full of all amounts due or to become due on or in respect of all Senior Debt in
cash before the Holders of the Securities are entitled to receive any payment on
account of principal of (or premium, if any) or interest on the Securities or on
account of the purchase, redemption or other acquisition of Securities, and to
that end the holders of Senior Debt 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, the Trustee or the Holder of any Security shall have received any
payment or distribution of assets of the Company of any kind or character,
whether in cash, securities or other property, before all Senior Debt is paid in
full, and if such fact shall, at or prior to the time of such payment or
distribution, have been made known to 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 Debt remaining unpaid, to the extent necessary to pay all Senior Debt in
full, after giving effect to any concurrent payment or distribution to or for
the holders of Senior Debt.

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          For purposes of this Article only, the words "cash, securities or
other property" 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
shares of stock or securities are subordinated in right of payment to all then
outstanding Senior Debt to substantially the same extent as, or to a greater
extent than, the Securities are so subordinated as provided in this Article. 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 VII 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 Section 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 VII.

          In the event that, notwithstanding the foregoing, the Company shall
make any payment to the Trustee or the Holder of any Security prohibited by the
foregoing provisions of this Section, and if such fact shall, at or prior to the
time of such payment, have been made known to 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, in the case of the Trustee, or the Trustee,
in the case of such Holder.

          SECTION 13.3 PRIOR PAYMENT TO SENIOR DEBT UPON ACCELERATION OF
SECURITIES. In the event of the acceleration of the Securities because of an
Event of Default, no payment or distribution shall be made to the Trustee or any
holder of Securities in respect of the principal of, premium, if any, or
interest on the Securities (including, but not limited to, the Redemption Price
with respect to the Securities called for redemption in accordance with Article
XI or the Repurchase Price with respect to the Securities submitted for
repurchase in accordance with Article XIV), except payments and distributions
made by the Trustee as permitted by Section 13.9, until all Senior Debt has been
paid in full in cash or other payment satisfactory to the holders of Senior Debt
or such acceleration is rescinded in accordance with the terms of this
Indenture. If payment of the Securities is accelerated because of an Event of
Default, the Company shall promptly notify holders of Senior Debt of the
acceleration.

          SECTION 13.4 PAYMENT PERMITTED IF NO DEFAULT. Nothing contained in
this Article or elsewhere in this Indenture 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 13.2, or during the circumstances referred to in
the first paragraph of Section 13.2, or under the conditions described in
Section 13.3, from making payments at any time of principal of (and premium, if
any) or interest on the Securities, 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 the Securities or the
retention of such payment by the Holders, if, at the time of such application by
the Trustee, it did not have knowledge that such payment would have been
prohibited by the provisions of this Article.

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          SECTION 13.5 SUBROGATION TO RIGHTS OF HOLDERS OF SENIOR DEBT. Subject
to the payment in full of all Senior Debt, the Holders of the Securities shall
be subrogated to the extent of the payments or distributions made to the holders
of such Senior Debt pursuant to the provisions of this Article to the rights of
the holders of such Senior Debt to receive payments and distributions of cash,
property and securities applicable to the Senior Debt until the principal of
(and premium, if any) and interest on the Securities shall be paid in full. For
purposes of such subrogation, no payments or distributions to the holders of the
Senior Debt 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, and no payments over pursuant to the provisions of this Article to the
holders of Senior Debt by Holders of the Securities or the Trustee, shall, as
among the Company, its creditors other than holders of Senior Debt and the
Holders of the Securities, be deemed to be a payment or distribution by the
Company to or on account of the Senior Debt.

          SECTION 13.6 PROVISIONS SOLELY TO DEFINE RELATIVE RIGHTS. The
provisions of this Article 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 Debt on the other hand. Nothing contained in this
Article or elsewhere in this Indenture or in the Securities is intended to or
shall (i) impair, as among the Company, its creditors other than holders of
Senior Debt and the Holders of the Securities, the obligation of the Company,
which is absolute and unconditional, to pay to the Holders of the Securities the
principal of (and premium, if any) and interest on the Securities as and when
the same shall become due and payable in accordance with their terms; or (ii)
affect the relative rights against the Company of the Holders of the Securities
and creditors of the Company other than the holders of Senior Debt; or (iii)
prevent the Trustee or the Holder of any Security from exercising all remedies
otherwise permitted by applicable law upon default under this Indenture, subject
to the rights, if any, under this Article of the holders of Senior Debt to
receive cash, property and securities otherwise payable or deliverable to the
Trustee or such Holder.

          SECTION 13.7 TRUSTEE TO EFFECTUATE SUBORDINATION. Each Holder of a
Security 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 and appoints the Trustee its
attorney-in-fact for any and all such purposes.

          SECTION 13.8 NO WAIVER OF SUBORDINATION PROVISIONS. No right of any
present or future holder of any Senior Debt 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 non-compliance 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 Debt 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 or the obligations
hereunder of the Holders of the Securities to the holders of Senior Debt, do any
one or more of the following: (i) change the manner, place or terms of payment
or extend the time of payment of, or renew or alter, Senior Debt, or otherwise
amend or supplement in any manner

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Senior Debt or any instrument evidencing the same or any agreement under which
Senior Debt is outstanding; (ii) sell, exchange, release or otherwise deal with
any property pledged, mortgaged or otherwise securing Senior Debt; (iii) release
any Person liable in any manner for the collection of Senior Debt; and (iv)
exercise or refrain from exercising any rights against the Company and any other
Person.

          SECTION 13.9 NOTICE TO TRUSTEE. The Company shall give prompt written
notice to the Trustee of any fact known to the Company which would prohibit the
making of any payment to or by the Trustee in respect of the Securities.
Notwithstanding the provisions of this Article or any other provision of this
Indenture, the Trustee shall not be charged with knowledge of the existence of
any facts which would prohibit the making of any payment to or by the Trustee in
respect of the Securities, unless and until a Responsible Officer of the Trustee
shall have received written notice thereof from the Company or a Representative
or a holder of Senior Debt (including, without limitation, a holder of
Designated Senior Debt) and, prior to the receipt of any such written notice,
the Trustee, subject to the provisions of Section 6.1, shall be entitled in all
respects to assume that no such facts exist; provided, however, that if the
Trustee shall not have received the notice provided for in this Section 13.9 at
least two Business Days prior to the date upon which by the terms hereof any
money may become payable for any purpose (including, without limitation, 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 one Business Day
prior to such date.

          Notwithstanding anything in this Article XIII to the contrary, nothing
shall prevent any payment by the Trustee to the Holders of monies deposited with
it pursuant to Section 4.1, and any such payment shall not be subject to the
provisions of Section 13.2 or 13.3.

          Subject to the provisions of Section 6.1, the Trustee shall be
entitled to rely on the delivery to it of a written notice by a Person
representing himself to be a Representative or a holder of Senior Debt
(including, without limitation, a holder of Designated Senior Debt) to establish
that such notice has been given by a Representative or a holder of Senior Debt
(including, without limitation, a holder of Designated Senior Debt). 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 Debt to
participate in any payment or distribution pursuant to this Article, the Trustee
may request such Person to furnish evidence to the reasonable satisfaction of
the Trustee as to the amount of Senior Debt 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, 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 13.10 RELIANCE ON JUDICIAL ORDER OR CERTIFICATE OF LIQUIDATING
AGENT. Upon any payment or distribution of assets of the Company referred to in
this Article, the Trustee, subject to the provisions of Section 6.1, 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

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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 Debt 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.

          SECTION 13.11 TRUSTEE NOT FIDUCIARY FOR HOLDERS OF SENIOR DEBT. The
Trustee shall not be deemed to owe any fiduciary duty to the holders of Senior
Debt 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
Debt shall be entitled by virtue of this Article or otherwise.

          SECTION 13.12 RELIANCE BY HOLDERS OF SENIOR DEBT ON SUBORDINATION
PROVISIONS. Each Holder by accepting a Security acknowledges and agrees that the
foregoing subordination provisions are, and are intended to be, an inducement
and a consideration to each holder of any Senior Debt, whether such Senior Debt
was created or acquired before or after the issuance of the Securities, to
acquire and continue to hold, or to continue to hold, such Senior Debt and such
holder of Senior Debt shall be deemed conclusively to have relied on such
subordination provisions in acquiring and continuing to hold, or in continuing
to hold, such Senior Debt, and no amendment or modification of the provisions
contained herein shall diminish the rights of such holders of Senior Debt unless
such holders shall have agreed in writing thereto.

          SECTION 13.13 RIGHTS OF TRUSTEE AS HOLDER OF SENIOR DEBT; PRESERVATION
OF TRUSTEE'S RIGHTS. The Trustee in its individual capacity shall be entitled to
all the rights set forth in this Article with respect to any Senior Debt which
may at any time be held by it, to the same extent as any other holder of Senior
Debt, and nothing in this Indenture shall deprive the Trustee of any of its
rights as such holder.

          Nothing in this Article shall apply to claims of, or payments to, the
Trustee under or pursuant to Section 6.7.

          SECTION 13.14 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 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 in addition to
or in place of the Trustee; provided, however, that Section 13.13 shall not
apply to the Company or any Affiliate of the Company if it or such Affiliate
acts as Paying Agent.

          SECTION 13.15 CERTAIN CONVERSIONS AND REPURCHASES DEEMED PAYMENT. For
the purposes of this Article only, (i) the issuance and delivery of junior
securities upon conversion of Securities in accordance with Article XII or upon
the repurchase of Securities in accordance with Article XIV 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 purchase or

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other acquisition of Securities, and (ii) the payment, issuance or delivery of
cash (except in satisfaction of fractional shares pursuant to Section 12.3 or
14.3(7)), 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, the term "junior securities"
means (a) shares of any stock of any class of the Company and securities into
which the Securities are convertible pursuant to Article XII and (b) securities
of the Company which are subordinated in right of payment to all Senior Debt
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. Nothing contained in this
Article 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
Debt 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 XII or to exchange such Security for Common Stock in
accordance with Article XIV if the Company elects to satisfy the obligations
under Article XIV by the delivery of Common Stock.

                                  ARTICLE XIV

                  REPURCHASE OF SECURITIES AT THE OPTION OF THE

                         HOLDER UPON A CHANGE IN CONTROL

          SECTION 14.1 RIGHT TO REQUIRE REPURCHASE. In the event that a Change
in Control (as hereinafter defined) shall occur, then each Holder shall have the
right, at the Holder's option, but subject to the provisions of Section 14.2, to
require the Company to repurchase, and upon the exercise of such right the
Company shall repurchase, all of such Holder's Securities not theretofore called
for redemption, or any portion of the principal amount thereof that is equal to
U.S. $1,000 or any integral multiple of U.S. $1,000 in excess thereof (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 U.S. $1,000 or integral multiples of U.S. $1,000 in excess thereof), on
the date (the "Repurchase Date") that is 45 days after the date of the Company
Notice (as defined in Section 14.3) at a purchase price equal to 100% of the
principal amount of the Securities to be repurchased plus interest accrued to
the Repurchase Date (the "Repurchase Price"); provided, however, that
installments of interest on Securities whose Stated Maturity is on or prior to
the Repurchase Date shall be payable to the Holders of such Securities, or one
or more Predecessor Securities, registered as such on the relevant Record Date
according to their terms and the provisions of Section 3.9. Such right to
require the repurchase of the Securities shall not continue after a discharge of
the Company from its obligations with respect to the Securities in accordance
with Article IV, unless a Change in Control shall have occurred prior to such
discharge. 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 14.2, by delivery of shares of Common Stock that have been registered
under the Securities Act having a fair market value equal to the Repurchase
Price. Whenever in this Indenture (including Sections 2.2, 3.1, 5.1(1) and 5.8)
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

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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 Article XIII such
reference shall be deemed to include reference to the Repurchase Price only to
the extent the Repurchase Price is payable in cash.

          SECTION 14.2 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 14.1 if and only
if the following conditions shall have been satisfied:

          (1) 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 Section 14.1 and
     this Section 14.2, 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 Per Share of the Common Stock for the 20 consecutive Trading
     Days immediately preceding and including the third Trading Day prior to the
     Repurchase Date;

          (2) the Repurchase Price shall be paid only in cash in the event any
     shares of Common Stock to be issued upon repurchase of Securities hereunder
     (i) require registration under any federal securities law before such
     shares may be freely transferable without being subject to any transfer
     restrictions under the Securities Act upon repurchase and if such
     registration is not completed or does not become effective prior to the
     Repurchase Date, and/or (ii) require registration with or approval of any
     governmental authority under any state law or any other federal law before
     such shares may be validly issued or delivered upon repurchase and if such
     registration is not completed or does not become effective or such approval
     is not obtained prior to the Repurchase Date;

          (3) payment of the Repurchase Price may not be made in Common Stock
     unless such stock is, or shall have been, approved for quotation on the
     Nasdaq National Market or listed on a national securities exchange, in
     either case, prior to the Repurchase Date; and

          (4) all shares of Common Stock which may be issued upon repurchase of
     Securities will 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 or similar rights.

          If all of the conditions set forth in this Section 14.2 are not
satisfied in accordance with the terms thereof, the Repurchase Price shall be
paid by the Company only in cash.

          SECTION 14.3 NOTICES; METHOD OF EXERCISING REPURCHASE RIGHT, ETC.
Unless the Company shall have theretofore called for redemption all of the
Outstanding Securities, on or before the 45th day after the occurrence of a
Change in Control, the Company or, at the request

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and expense of the Company on or before the 15th day after such occurrence, the
Trustee, shall give to all Holders of Securities, in the manner provided in
Section 1.6, notice (the "Company Notice") of the occurrence of the Change of
Control and of the repurchase right set forth herein arising as a result thereof
and the Company shall issue a Press Release including the information required
to be included in such Company Notice hereunder. The Company shall also deliver
a copy of such Company Notice to the Trustee.

          (1) Each Company Notice shall state:

          (i) the Repurchase Date,

          (ii) the date by which the repurchase right must be exercised,

          (iii) the Repurchase Price, and whether the Repurchase Price shall be
     paid by the Company in cash or by delivery of shares of Common Stock that
     have been registered under the Securities Act,

          (iv) a description of the procedure which a Holder must follow to
     exercise a repurchase right, and the place or places where such Securities
     are to be surrendered for payment of the Repurchase Price and accrued
     interest, if any to the Repurchase Date,

          (v) that on the Repurchase Date the Repurchase Price, and accrued
     interest, if any to the Repurchase Date, will become due and payable upon
     each such Security designated by the Holder to be repurchased, and that
     interest thereon shall cease to accrue on and after said date,

          (vi) the Conversion Rate then in effect, the date on which the
     right to convert the principal amount of the Securities to be repurchased
     will terminate and the place or places where such Securities may be
     surrendered for conversion, and

          (vii) the place or places that the Security certificate with the
     Election of Holder to Require Repurchase as specified in Section 2.2 shall
     be delivered.

          No failure of the Company to give the foregoing notices 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 Securities.

          If any of the foregoing provisions or other provisions of this Article
XIV are inconsistent with applicable law, such law shall govern.

          (2) To exercise a repurchase right, a Holder shall deliver to the
Trustee on or before the 30th day after the date of the Company Notice (i)
irrevocable written notice of the Holder's exercise of such right, which notice
shall set forth the name of the Holder, the principal amount of the Securities
to be repurchased (and, if any Security is to repurchased in part, the serial
number thereof, 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, and, in the event that the
Repurchase Price shall be paid in shares of Common Stock, the

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name or names (with addresses) in which the certificate or certificates for
shares of Common Stock shall be issued, and (ii) the Securities with respect to
which the repurchase right is being exercised. Such written notice shall be
irrevocable, except that the right of the Holder to convert the Securities with
respect to which the repurchase right is being exercised shall continue until
the close of business on the Business Day immediately preceding the Repurchase
Date.

          (3) 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 Trustee
the Repurchase Price in cash or shares of Common Stock that have been registered
under the Securities Act, as provided above, for payment to the Holder on the
Repurchase Date or, if shares of Common Stock are to be paid, as promptly after
the Repurchase Date as practicable, together with accrued and unpaid interest to
the Repurchase Date payable with respect to the Securities as to which the
repurchase right has been exercised; provided, however, that installments of
interest that mature on or prior to the Repurchase Date shall be payable in cash
to the Holders of such Securities, or one or more Predecessor Securities,
registered as such at the close of business on the relevant Regular Record Date.

          (4) If any Security (or portion thereof) surrendered for repurchase
shall not be so paid on the Repurchase Date, the principal amount of such
Security (or portion thereof, as the case may be) shall, until paid, bear
interest to the extent permitted by applicable law from the Repurchase Date at
the rate of 7.50% per annum, and each Security shall remain convertible into
Common Stock until the principal of such Security (or portion thereof, as the
case may be) shall have been paid or duly provided for.

          (5) 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 make available for delivery 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 unrepurchased portion of the
principal of the Security so surrendered.

          (6) 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.

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          (7) No fractions of 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 issuable upon such repurchase shall be computed on
the basis of the aggregate principal amount of the Securities so repurchased.
Instead of any fractional share of Common Stock which would otherwise be
issuable on the repurchase of any Security or Securities, the Company will
deliver to the applicable Holder its check for the current market value of such
fractional share. The current market value of a fraction of a share is
determined by multiplying the current market price of a full share by the
fraction, and rounding the result to the nearest cent. For purposes of this
Section, the current market price of a share of Common Stock is the Closing
Price Per Share of the Common Stock on the Trading Day immediately preceding the
Repurchase Date.

          (8) Any issuance and delivery of certificates for shares of Common
Stock on repurchase of Securities shall be made without charge to the Holder of
Securities being repurchased for such certificates or for any tax or duty in
respect of the issuance or delivery of such certificates or the securities
represented thereby; provided, however, that the Company shall not be required
to pay any tax or duty which may be payable in respect of (i) income of the
Holder or (ii) any transfer involved in the issuance or delivery of certificates
for shares of Common Stock in a name other than that of the Holder of the
Securities being repurchased, and no such issuance or delivery shall be made
unless and until the Person requesting such issuance or delivery has paid to the
Company the amount of any such tax or duty or has established, to the
satisfaction of the Company, that such tax or duty has been paid.

          (9) All Securities delivered for repurchase shall be delivered to the
Trustee to be canceled at the direction of the Trustee, which shall dispose of
the same as provided in Section 3.11.

          SECTION 14.4 CERTAIN DEFINITIONS. For purposes of this Article XIV,

          (1) the term "beneficial owner" shall be determined in accordance with
     Rule 13d-3, as in effect on the date of the original execution of this
     Indenture, promulgated by the Commission pursuant to the Exchange Act;

          (2) a "Change in Control" shall be deemed to have occurred at the
     time, after the original issuance of the Securities, of:

          (1) the acquisition by any Person (including any syndicate or group
     deemed to be a "person" under Section 13(d)(3) of the Exchange Act) of
     beneficial ownership, directly or indirectly, through a purchase, merger or
     other acquisition transaction or series of transactions, of shares of
     capital stock of the Company entitling such person to exercise 50% or more
     of the total voting power of all shares of capital stock of the Company
     entitled to vote generally in the elections of directors, other than any
     such acquisition by the Company, any subsidiary of the Company or any
     employee benefit plan of the Company; or

          (2) any consolidation of the Company with, or merger of the Company
     into, any other Person, any merger of another Person into the Company, or
     any conveyance,

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     sale, transfer or lease of all or substantially all of the assets of the
     Company to another Person (other than (a) any such transaction (x) which
     does not result in any reclassification, conversion, exchange or
     cancellation of outstanding shares of capital stock of the Company and (y)
     pursuant to which the holders of 50% or more of the total voting power of
     all shares of the Company's capital stock entitled to vote generally in the
     election of directors immediately prior to such transaction have the
     entitlement to exercise, directly or indirectly, 50% or more of the total
     voting power of all shares of capital stock entitled to vote generally in
     the election of directors of the continuing or surviving corporation
     immediately after such transaction and (b) any merger which is effected
     solely to change the jurisdiction of incorporation of the Company and
     results in a reclassification, conversion or exchange of outstanding shares
     of Common Stock into solely shares of common stock); provided, however,
     that a Change in Control shall not be deemed to have occurred if (I) the
     Closing Price Per Share of the Common Stock for any five Trading Days
     within the period of 10 consecutive Trading Days ending immediately after
     the later of the Change in Control or the public announcement of the Change
     in Control (in the case of a Change in Control under clause (i) above) or
     the period of 10 consecutive Trading Days ending immediately before the
     Change in Control (in the case of a Change in Control under clause (ii)
     above) shall, in the case of each of such five Trading Days, equal or
     exceed 105% of the Conversion Price of the Securities in effect on each of
     such five Trading Days or (II) all of the consideration (excluding cash
     payments for fractional shares and cash payments made pursuant to
     dissenters' appraisal rights) in a merger or consolidation otherwise
     constituting a Change of Control under clause (i) and/or clause (ii) above
     consists of shares of common stock traded on a national securities exchange
     or quoted on the Nasdaq National Market (or will be so traded or quoted
     immediately following such merger or consolidation) and as a result of such
     merger or consolidation the notes become convertible solely into such
     common stock.

          (3) the term "Conversion Price" shall equal U.S. $1,000 divided by the
     Conversion Rate (rounded to the nearest cent); and

          (4) for purposes of Section 14.4(2)(i), 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, as in effect on the date of the
     original execution of this Indenture.

          SECTION 14.5 CONSOLIDATION, MERGER, ETC. In the case of any merger,
consolidation, conveyance, sale, transfer or lease of all or substantially all
of the assets of the Company to which Section 12.11 applies, in which the Common
Stock of the Company is changed or exchanged as a result into the right to
receive shares of stock and other securities or property or assets (including
cash) which includes shares of Common Stock of the Company or common stock of
another Person that are, or upon issuance will be, traded on a United States
national securities exchange or approved for trading on an established automated
over-the-counter trading market in the United States and such shares constitute
at the time such change or exchange becomes effective in excess of 50% of the
aggregate fair market value of such shares of stock and other securities,
property and assets (including cash) (as determined by the Company, which
determination shall be conclusive and binding), then the Person formed by such
consolidation or resulting from such merger or combination or which acquires the
properties or assets (including cash) of the Company, as the case may be, shall
execute and deliver to the

                                       94
<PAGE>   102

Trustee a supplemental indenture (which shall comply with the Trust Indenture
Act as in force at the date of execution of such supplemental indenture)
modifying the provisions of this Indenture relating to the right of Holders to
cause the Company to repurchase the Securities following a Change in Control,
including without limitation the applicable provisions of this Article XIV and
the definitions of the Common Stock and Change in Control, as appropriate, and
such other related definitions set forth herein as determined in good faith by
the Company (which determination shall be conclusive and binding), to make such
provisions apply in the event of a subsequent Change in Control to the common
stock and the issuer thereof if different from the Company and Common Stock of
the Company (in lieu of the Company and the Common Stock of the Company).

                                   ARTICLE XV

                      HOLDERS LISTS AND REPORTS BY TRUSTEE

                            AND COMPANY; NON-RECOURSE

          SECTION 15.1 COMPANY TO FURNISH TRUSTEE NAMES AND ADDRESSES OF
HOLDERS. The Company will furnish or cause to be furnished to the Trustee:

          (1) semi annually, not more than 15 days after the Regular Record
     Date, 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, and

          (2) at such other times as the Trustee may reasonably 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;

provided, however, that no such list need be furnished so long as the Trustee is
acting as Security Registrar.

          SECTION 15.2 PRESERVATION OF INFORMATION.

          (1) The Trustee shall preserve, in as current a form as is reasonably
practicable, the names and addresses of Holders contained in the most recent
list furnished to the Trustee as provided in Section 15.1 and the names and
addresses of Holders received by the Trustee in its capacity as Security
Registrar. The Trustee may destroy any list, if any, furnished to it as provided
in Section 15.1 upon receipt of a new list so furnished.

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

          (3) Every Holder of Securities, by receiving and holding the same,
agrees with the Company and the Trustee that neither the Company nor the Trustee
nor any agent of either of

                                       95
<PAGE>   103

them shall be held accountable by reason of any disclosure of information as to
names and addresses of Holders made pursuant to the Trust Indenture Act.

          SECTION 15.3 REPORTS BY TRUSTEE.

          (1) After this Indenture has been qualified under the Trust Indenture
Act, the Trustee shall transmit, within 60 days of fiscal year end to Holders
such reports concerning the Trustee and its actions under this Indenture as may
be required pursuant to the Trust Indenture Act at the times and in the manner
provided pursuant thereto.

          (2) After this Indenture has been qualified under the Trust Indenture
Act, a copy of each such report shall, at the time of such transmission to
Holders, be filed by the Trustee with each stock exchange upon which the
Securities are listed, with the Commission and with the Company. The Company
will notify the Trustee when the Securities are listed on any stock exchange.

          SECTION 15.4 REPORTS BY COMPANY. Whether or not the Company is then
required to file reports with the Commission, the Company shall file with the
Commission by Section 13(a) or 15(d) under the Securities Exchange Act if it
were subject thereto. The Company shall supply to the Trustee copies of such
reports and other information, within 120 days of fiscal year end. The Company
also shall comply with the other provisions of Trust Indenture Act Section
314(a).

                                  ARTICLE XVI

                    IMMUNITY OF INCORPORATORS, STOCKHOLDERS,

                             OFFICERS AND DIRECTORS

          SECTION 16.1 INDENTURE AND SECURITIES SOLELY CORPORATE OBLIGATIONS. No
recourse for the payment of the principal of or premium, if any, or interest on
any Security and no recourse under or upon any obligation, covenant or agreement
of the Company in this Indenture or in any supplemental indenture or in any
Security, or because of the creation of any indebtedness represented thereby,
shall be had against any incorporator, stockholder, employee, agent, officer, or
director or subsidiary, as such, past, present or future, 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; it
being expressly understood that all such liability is hereby waived and released
as a condition of, and as a consideration for, the execution of this Indenture
and the issue of the Securities.

                                       96
<PAGE>   104

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

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

                                           ALLIED RISER COMMUNICATIONS
                                           CORPORATION

                                           By: /s/ TODD C. DOSHIER
                                              ----------------------------------
                                                    Name: Todd C. Doshier
                                                    Title: Senior Vice President

                                           WILMINGTON TRUST COMPANY,
                                           as Trustee

                                           By: /s/ MICHAEL W. DIAZ
                                              ----------------------------------
                                                    Name: Michael W. Diaz
                                                    Title: Authorized Signer

                                       97
<PAGE>   105

                                                                       EXHIBIT A

                               Form of Certificate

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

Wilmington Trust Company
[Address]
[Address]
Attention: Corporate Trust and Agency Services

           Re: Allied Riser Communications Corporation (the "Company")
        7.50%, Convertible Subordinated Notes due 2007 (the "Securities")

Dear Sirs:

     This letter relates to U.S. $_________ principal amount of Securities
represented by a Security (the "Legended Security") which bears a legend
outlining restrictions upon transfer of such Legended Security. Pursuant to
Section 3.4 of the Indenture dated as of June 28, 2000 (the "Indenture")
relating to the Securities, we hereby certify that we are (or we will hold such
securities on behalf of) a person outside the United States to whom the
Securities could be transferred in accordance with Rule 904 of Regulation S
promulgated under the U.S. Securities Act of 1933. Accordingly, you are hereby
requested to exchange the legended certificate for an unlegended certificate
representing an identical principal amount of Securities, all in the manner
provided for in the Indenture.

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

                                                     Very truly yours,

                                                     [Name of Holder]

                                                     By:
                                                        ------------------------
                                                     Authorized Signature

                                      A-1
<PAGE>   106

                                                                       EXHIBIT B

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

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

Wilmington Trust Company
[Address]
[Address]
Attention: Corporate Trust and Agency Services

           Re: Allied Riser Communications Corporation (the "Company")
        7.50% Convertible Subordinated Notes due 2007 (the "Securities")

Dear Sirs:

     In connection with our proposed purchase of $_______________ aggregate
principal amount of the Securities, we confirm that:

     1. We understand that any subsequent transfer of the Securities is subject
to certain restrictions and conditions set forth in the Indenture dated as of
June 28, 2000 (the "Indenture") relating to the Securities and the undersigned
agrees to be bound by, and not to resell, pledge or otherwise transfer the
Securities except in compliance with such restrictions and conditions and the
Securities Act of 1933, amended (the "Securities Act").

     2. We understand that the offer and sale of the Securities have not been
registered under the Securities Act, and that the Securities may not be offered
or sold except as permitted in the following sentence. We agree, on our own
behalf and on behalf of any accounts for which we are acting as hereinafter
stated, that if we should sell any Securities within the time period referred to
in Rule 144(k) of the Securities Act, we will do so only (A) to the Company or
any subsidiary thereof, (B) in accordance with Rule 144A under the Securities
Act to a "qualified institutional buyer" (as defined therein), (C) to an
institutional "accredited investor" (as defined below) that, prior to such
transfer, furnishes (or has furnished on its behalf by a U.S. broker-dealer) to
you and to the Company a signed letter substantially in the form of this letter
and, if such transfer is in respect of an aggregate principal amount of less
than $100,000, an opinion of counsel acceptable to the Company that such
transfer is in compliance with the Securities Act, (D) outside the United States
in accordance with Rule 904 of Regulation S under the Securities Act, (E)
pursuant to the exemption from registration provided by Rule 144 under the
Securities Act (if available) or (F) pursuant to an effective registration
statement under the Securities Act, and we further agree to provide to any
person purchasing any of the Securities from us a notice advising such purchaser
that resales of the Securities are restricted as stated herein.

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

                                      B-1
<PAGE>   107

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

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

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

                                             Very truly yours,

                                             [Name of Transferee]

                                             By:
                                                --------------------------------
                                                  Authorized Signature

                                      B-2
<PAGE>   108

                                                                       EXHIBIT C

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

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

Wilmington Trust Company
[Address]
[Address]
Attention: Corporate Trust and Agency Services

           Re: Allied Riser Communications Corporation (the "Company")
        ___%, Convertible Subordinated Notes due 2007 (the "Securities")

Dear Sirs:

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

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

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

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

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

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

                                              Very truly yours,

                                              [Name of Transferor]

                                              By:
                                                 -------------------------------
                                                 Authorized Signature

                                      C-1

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