<PAGE>   1

                                                                    EXHIBIT 4.1

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                             Quanta Services, Inc.,
                                   as Issuer

                                       to

                   Chase Bank of Texas, National Association
                                   as Trustee


                                   ----------


                             SUBORDINATED INDENTURE

                           Dated as of July 25, 2000


                                   ----------









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                               TABLE OF CONTENTS

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<TABLE>
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<S>                                                                                                              <C>
PARTIES           ................................................................................................1

RECITALS OF THE COMPANY...........................................................................................1

ARTICLE ONE:  DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION.............................................1
         Section 101.  Definitions................................................................................1
                  Act.............................................................................................1
                  Affiliate.......................................................................................2
                  Authenticating Agent............................................................................2
                  Board of Directors..............................................................................2
                  Board Resolution................................................................................2
                  Business Day....................................................................................2
                  Capital Stock...................................................................................2
                  Commission......................................................................................2
                  Common Stock....................................................................................2
                  Company.........................................................................................2
                  Company Request.................................................................................2
                  Company Order...................................................................................2
                  Conversion Agent................................................................................2
                  Conversion Price................................................................................2
                  Conversion Shares...............................................................................3
                  Corporate Trust Office..........................................................................3
                  Corporation.....................................................................................3
                  Covenant Defeasance.............................................................................3
                  Defaulted Interest..............................................................................3
                  Defeasance......................................................................................3
                  Depositary......................................................................................3
                  Designated Senior Debt..........................................................................3
                  Distribution Date...............................................................................3
                  Event of Default................................................................................3
                  Exchange Act....................................................................................3
                  Expiration Date.................................................................................3
                  Expiration Time.................................................................................3
                  Global Security.................................................................................3
                  Holder..........................................................................................3
                  Indenture.......................................................................................3
                  Interest .......................................................................................4
                  Interest Payment Date...........................................................................4
                  Investment Company Act..........................................................................4
                  Last Sale Price.................................................................................4
                  Maturity........................................................................................4
                  Notice of Default...............................................................................4
                  Offer...........................................................................................4
                  Officer's Certificate...........................................................................4
                  Opinion of Counsel..............................................................................4
                  Original Issue Discount Security................................................................4
</TABLE>


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<TABLE>

<S>                                                                                                              <C>
                  Outstanding.....................................................................................4
                  Paying Agent....................................................................................5
                  Person..........................................................................................5
                  Place of Payment................................................................................5
                  Predecessor Security............................................................................5
                  Redemption Date.................................................................................5
                  Redemption Price................................................................................6
                  Regular Record Date.............................................................................6
                  Responsible Officer.............................................................................6
                  Securities......................................................................................6
                  Securities Act..................................................................................6
                  Security Register...............................................................................6
                  Security Registrar..............................................................................6
                  Senior Debt.....................................................................................6
                  Senior Nonmonetary Default......................................................................6
                  Senior Payment Default..........................................................................6
                  Significant Subsidiary..........................................................................6
                  Special Record Date.............................................................................6
                  Stated Maturity.................................................................................6
                  Subsidiary......................................................................................6
                  Trading Day.....................................................................................6
                  Trust Indenture Act.............................................................................7
                  Trustee.........................................................................................7
                  U.S. Government Obligation......................................................................7
                  Vice President..................................................................................7
                  Voting Stock....................................................................................7
                  Wholly Owned Subsidiary.........................................................................7
         Section 102.  Compliance Certificates and Opinions.......................................................7
         Section 103.  Form of Documents Delivered to Trustee.....................................................8
         Section 104.  Acts of Holders; Record Dates..............................................................8
         Section 105.  Notices, Etc., to Trustee and Company......................................................9
         Section 106.  Notice to Holders; Waiver.................................................................10
         Section 107.  Conflict with Trust Indenture Act.........................................................10
         Section 108.  Effect of Headings and Table of Contents..................................................10
         Section 109.  Successors and Assigns....................................................................11
         Section 110.  Separability Clause.......................................................................11
         Section 111.  Benefits of Indenture.....................................................................11
         Section 112.  Governing Law.............................................................................11
         Section 113.  Legal Holidays............................................................................11
         Section 114.  Counterparts..............................................................................11
ARTICLE TWO:  SECURITY FORMS.....................................................................................12
         Section 201.  Forms Generally...........................................................................12
         Section 202.  Form of Face of Security..................................................................12
         Section 203.  Form of Reverse of Security...............................................................14
         Section 205.  Form of Legend for Global Securities......................................................17
         Section 206.  Form of Trustee's Certificate of Authentication...........................................18
         Section 207.  Form of Conversion Notice.................................................................19
ARTICLE THREE:  THE SECURITIES...................................................................................20
         Section 301.  Amount Unlimited; Issuable in Series......................................................20
         Section 302.  Denominations.............................................................................22
         Section 303.  Execution, Authentication, Delivery and Dating............................................22
</TABLE>

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<TABLE>

<S>                                                                                                             <C>
         Section 304.  Temporary Securities......................................................................24
         Section 305.  Registration, Registration of Transfer and Exchange.......................................24
         Section 306.  Mutilated, Destroyed, Lost and Stolen Securities..........................................25
         Section 307.  Payment of Interest; Interest Rights Preserved............................................26
         Section 308.  Persons Deemed Owners.....................................................................27
         Section 309.  Cancellation..............................................................................28
         Section 310.  Computation of Interest...................................................................28
ARTICLE FOUR:  SATISFACTION AND DISCHARGE........................................................................28
         Section 401.  Satisfaction and Discharge of Indenture...................................................28
         Section 402.  Application of Trust Money................................................................29
ARTICLE FIVE:  REMEDIES..........................................................................................29
         Section 501.  Events of Default.........................................................................29
         Section 502.  Acceleration of Maturity; Rescission and Annulment........................................31
         Section 503.  Collection of Indebtedness and Suits for Enforcement by Trustee...........................32
         Section 504.  Trustee May File Proofs of Claim..........................................................32
         Section 505.  Trustee May Enforce Claims Without Possession of Securities...............................33
         Section 506.  Application of Money Collected............................................................33
         Section 507.  Limitation on Suits.......................................................................33
         Section 508.  Unconditional Right of Holders to Receive Principal,
                             Premium and Interest................................................................34
         Section 509.  Restoration of Rights and Remedies........................................................34
         Section 510.  Rights and Remedies Cumulative............................................................34
         Section 511.  Delay or Omission Not Waiver..............................................................34
         Section 512.  Control by Holders........................................................................35
         Section 513.  Waiver of Past Defaults...................................................................35
         Section 514.  Undertaking for Costs.....................................................................35
         Section 515.  Waiver of Usury, Stay or Extension Laws...................................................35
ARTICLE SIX:  THE TRUSTEE........................................................................................36
         Section 601.  Certain Duties and Responsibilities.......................................................36
         Section 602.  Notice of Defaults........................................................................36
         Section 603.  Certain Rights of Trustee.................................................................36
         Section 604.  Not Responsible for Recitals or Issuance of Securities....................................38
         Section 605.  May Hold Securities.......................................................................38
         Section 606.  Money Held in Trust.......................................................................38
         Section 607.  Compensation and Reimbursement............................................................38
         Section 608.  Conflicting Interests.....................................................................39
         Section 609.  Corporate Trustee Required; Eligibility...................................................39
         Section 610.  Resignation and Removal; Appointment of Successor.........................................39
         Section 611.  Acceptance of Appointment by Successor....................................................40
         Section 612.  Merger, Conversion, Consolidation or Succession to Business...............................41
         Section 613.  Preferential Collection of Claims Against Company.........................................42
         Section 614.  Appointment of Authenticating Agent.......................................................42
ARTICLE SEVEN:  HOLDERS' LISTS AND REPORTS BY TRUSTEE
         AND COMPANY.............................................................................................43
         Section 701.  Company to Furnish Trustee Names and Addresses of Holders.................................43
         Section 702.  Preservation of Information; Communications to Holders....................................43
         Section 703.  Reports by Trustee........................................................................44
         Section 704.  Reports by Company........................................................................44
ARTICLE EIGHT:  CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER
         OR LEASE................................................................................................44
         Section 801.  Company May Consolidate, Etc., Only on Certain Terms......................................44
</TABLE>


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<TABLE>

<S>                                                                                                             <C>
         Section 803.  Successor Substituted.....................................................................45
ARTICLE NINE:  SUPPLEMENTAL INDENTURES...........................................................................45
         Section 901.  Supplemental Indentures Without Consent of Holders........................................45
         Section 902.  Supplemental Indentures With Consent of Holders...........................................46
         Section 903.  Execution of Supplemental Indentures......................................................47
         Section 904.  Effect of Supplemental Indentures.........................................................48
         Section 905.  Conformity with Trust Indenture Act.......................................................48
         Section 906.  Reference in Securities to Supplemental Indentures........................................48
ARTICLE TEN:  COVENANTS..........................................................................................48
         Section 1001. Payment of Principal, Premium and Interest................................................48
         Section 1002. Maintenance of Office or Agency...........................................................49
         Section 1003. Money for Securities Payments to Be Held in Trust.........................................49
         Section 1004. Statement by Officers as to Default.......................................................50
         Section 1005. Existence.................................................................................50
         Section 1006. Maintenance of Properties.................................................................50
         Section 1007. Payment of Taxes and Other Claims.........................................................51
         Section 1008. Maintenance of Insurance..................................................................51
         Section 1009. Waiver of Certain Covenants...............................................................51
ARTICLE ELEVEN:  REDEMPTION OF SECURITIES........................................................................51
         Section 1101. Applicability of Article..................................................................51
         Section 1102. Election to Redeem; Notice to Trustee.....................................................52
         Section 1103. Selection by Trustee of Securities to Be Redeemed.........................................52
         Section 1104. Notice of Redemption......................................................................53
         Section 1105. Deposit of Redemption Price...............................................................53
         Section 1106. Securities Payable on Redemption Date.....................................................54
         Section 1107. Securities Redeemed in Part...............................................................54
ARTICLE TWELVE:  SUBORDINATION OF SECURITIES.....................................................................54
         Section 1201. Applicability of Article..................................................................54
         Section 1202. Securities Subordinate to Senior Debt.....................................................54
         Section 1203. Payment Over of Proceeds Upon Dissolution, Etc............................................55
         Section 1204. No Payment When Senior Debt of the Company in Default.....................................56
         Section 1205. Payment Permitted If No Default...........................................................57
         Section 1206. Subrogation to Rights of Holders of Senior Debt of the Company............................57
         Section 1207. Provisions Solely to Define Relative Rights...............................................58
         Section 1208. Trustee to Effectuate Subordination.......................................................58
         Section 1209. No Waiver of Subordination Provisions.....................................................58
         Section 1210. Notice to Trustee.........................................................................59
         Section 1211. Reliance on Judicial Order or Certificate of Liquidating Agent............................59
         Section 1212. Trustee Not Fiduciary for Holders of Senior Debt of the Company...........................60
         Section 1213. Rights of Trustee as Holder of Senior Debt of the Company;
                             Preservation of Trustee's Rights....................................................60
         Section 1214. Article Applicable to Paying Agents.......................................................60
         Section 1215. Defeasance of this Article Twelve.........................................................60
ARTICLE THIRTEEN:  [INTENTIONALLY OMITTED].......................................................................60
ARTICLE FOURTEEN:  [INTENTIONALLY OMITTED].......................................................................60
ARTICLE FIFTEEN:  DEFEASANCE AND COVENANT DEFEASANCE.............................................................61
         Section 1501. Company's Option to Effect Defeasance or Covenant Defeasance..............................61
         Section 1502. Defeasance and Discharge..................................................................61
         Section 1503. Covenant Defeasance.......................................................................61
         Section 1504. Conditions to Defeasance or Covenant Defeasance...........................................62
</TABLE>


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<TABLE>

<S>                                                                                                              <C>
         Section 1505. Deposited Money and U.S. Government Obligations to Be Held
                             in Trust; Miscellaneous Provisions..................................................63
         Section 1506. Reinstatement.............................................................................64
ARTICLE SIXTEEN:  SINKING FUNDS..................................................................................64
         Section 1601. Applicability of Article..................................................................64
         Section 1602. Satisfaction of Sinking Fund Payments with Securities.....................................65
         Section 1603. Redemption of Securities for Sinking Fund.................................................65
ARTICLE SEVENTEEN:  CONVERSION OF SECURITIES.....................................................................65
         Section 1701. Applicability of Article..................................................................65
         Section 1702. Exercise of Conversion Privilege..........................................................65
         Section 1703. Fractional Interests......................................................................67
         Section 1704. Adjustment of Conversion Price............................................................67
         Section 1705. Continuation of Conversion Privilege in Case of Merger, Consolidation
                             or Sale of Assets...................................................................71
         Section 1706. Notice of Certain Events..................................................................72
         Section 1707. Taxes on Conversion.......................................................................73
         Section 1708. Company to Provide Stock..................................................................73
         Section 1709. Disclaimer of Responsibility for Certain Matters..........................................73
         Section 1710. Return of Funds Deposited for Redemption of Converted Securities..........................74
</TABLE>

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<PAGE>   7
                             QUANTA SERVICES, INC.

          CERTAIN SECTIONS OF THIS INDENTURE RELATING TO SECTIONS 310
          THROUGH 318, INCLUSIVE, OF THE TRUST INDENTURE ACT OF 1939:

<TABLE>
<CAPTION>

TRUST INDENTURE
  ACT SECTION                                                                           INDENTURE SECTION

<S>                                                                                                         <C>
Section 310(a)(1)............................................................................................609
         (a)(2)..............................................................................................609
         (a)(3)...................................................................................Not Applicable
         (a)(4) ..................................................................................Not Applicable
         (b).................................................................................................608
         ....................................................................................................610
Section 311(a)...............................................................................................613
         (b).................................................................................................613
Section 312(a)...............................................................................................701
         ....................................................................................................702
         (b)................................................................................................ 702
         (c)................................................................................................ 702
Section 313(a).............................................................................................. 703
         (b).................................................................................................703
         (c).................................................................................................703
         (d).................................................................................................703
Section 314(a)...............................................................................................704
         (a)(4)..............................................................................................101
         ...................................................................................................1004
         (b)......................................................................................Not Applicable
         (c)(1)..............................................................................................102
         (c)(2)..............................................................................................102
         (c)(3)...................................................................................Not Applicable
         (d)......................................................................................Not Applicable
         (e).................................................................................................102
Section 315(a)...............................................................................................601
         (b).................................................................................................602
         (c).................................................................................................601
         (d).................................................................................................601
         (e).................................................................................................514
Section 316(a)...............................................................................................101
         (a)(1)(A)...........................................................................................502
         ....................................................................................................512
         (a)(1)(B)...........................................................................................513
         (a)(2)...................................................................................Not Applicable
         (b).................................................................................................508
         (c).................................................................................................104
Section 317(a)(1)............................................................................................503
         (a)(2)..............................................................................................504
         (b).................................................................................................003
Section 318(a)...............................................................................................107
</TABLE>

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



                                       vi


<PAGE>   8

         INDENTURE, dated as of July 25, 2000, among Quanta Services, Inc., a
corporation duly organized and existing under the laws of the State of Delaware
(herein called the "Company"), having its principal office at 1360 Post Oak
Blvd., Suite 2100, Houston, Texas 770056, and Chase Bank of Texas, National
Association, a national banking association as Trustee (herein called the
"Trustee").


                            RECITALS OF THE COMPANY

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

         All things necessary to make this Indenture a valid agreement of the
Company, in accordance with its terms, have been done.

         NOW, THEREFORE, THIS INDENTURE WITNESSETH:

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

                                  ARTICLE ONE

                        DEFINITIONS AND OTHER PROVISIONS
                             OF GENERAL APPLICATION

SECTION 101. Definitions.

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

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

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

                  (3) all accounting terms not otherwise defined herein have
         the meanings assigned to them in accordance with generally accepted
         accounting principles, and, except as otherwise herein expressly
         provided, the term "generally accepted accounting principles" with
         respect to any computation required or permitted hereunder shall mean
         such accounting principles as are generally accepted at the date of
         this instrument;

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

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

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

         "Affiliate" of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified Person. For the purposes of



                                       1
<PAGE>   9

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; provided that direct or indirect beneficial
ownership of 10% or more of the Voting Stock of a Person shall be deemed to
control; provided, however that UtiliCorp United, Inc. and its respective
Affiliates (other than the Company's Subsidiaries) shall not be deemed to be
Affiliates of the Company unless and until UtiliCorp United Inc. or any
Affiliate thereof (other than the Company's Subsidiaries) acquires beneficial
ownership of more than 49.9% of the total number of shares of outstanding
Common Stock (on an as converted basis assuming full conversion of all
securities convertible into Common Stock).

         "As - Converted Series A Preferred Shares" means that number of shares
of Common Stock into which the outstanding shares of Series A Preferred Stock
are convertible at any time.

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

         "Board of Directors" means, with respect to the Company, either the
board of directors of the Company or any committee of that board duly
authorized to act for it in respect hereof.

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

         "Business Day", when used with respect to any Place of Payment, means
each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day on
which banking institutions in that Place of Payment are authorized or obligated
by law or executive order to close.

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

         "Commission" means the Securities and Exchange Commission, 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 $.00001 per share, of
the Company as the same exists at the date of execution and delivery of this
Indenture or other capital stock of the Company into which such Common Stock is
converted, reclassified or changed from time to time.

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

         "Company Request" or "Company Order" means a written request or order
signed in the name of the Company by its Chairman of the Board, its Vice
Chairman of the Board, its President or a Vice President, and delivered to the
Trustee.


                                       2
<PAGE>   10

         "Conversion Agent" means any Person authorized by the Company to
convert any Securities on behalf of the Company.

         "Conversion Price" has the meaning specified in Section 1704.

         "Conversion Shares" has the meaning specified in Section 1704(k).

         "Corporate Trust Office" means the principal office of the Trustee as
follows: (a) for registration or transfer of the Securities: Chase Bank of
Texas, National Association, 2001 Bryan Street, 9th Street, Dallas, Texas
75201, telephone: (800) 275-2048, telecopy: (214) 672-5873; (b) for payment of
the Securities, as agent for the Trustee, The Chase Manhattan Bank, 55 Water
Street, Room 234, New York, New York 10041, telephone (212) 638-0454, telecopy
(212) 638-7380; and (c) for all other communications relating to the
Securities: Chase Bank of Texas, National Association, Capital Markets
Fiduciary Services, 600 Travis Street, Suite 1150, Houston, Texas 77002,
telephone (713) 216-6877, telecopy (713) 577-5200.

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

         "Covenant Defeasance" has the meaning specified in Section 1503.

         "Date of Conversion" has the meaning set forth in Section 1702.

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

         "Defeasance" has the meaning specified in Section 1502.

         "Depositary" means, with respect to Securities of any series issuable
in whole or in part in the form of one or more Global Securities, a clearing
agency registered under the Exchange Act that is designated to act as
Depositary for such Securities as contemplated by Section 301.

         "Designated Senior Debt" with respect to any series of Securities
shall have the meaning specified as contemplated by Section 301.

         "Distribution Date" has the meaning specified in Section 1704(k).

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

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

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

         "Expiration Time" has the meaning specified in Section 1704(e).

         "Global Security" means a Security that evidences all or part of the
Securities of any series and bears the legend set forth in Section 205 (or such
legend as may be specified as contemplated by Section 301 for such Securities).

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



                                       3
<PAGE>   11

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

         "Insolvency or Liquidation Proceeding" has the meaning specified in
Section 607.

         "interest", when used with respect to an Original Issue Discount
Security which by its terms bears interest only after Maturity or after a
specified date, means such interest payable only after Maturity or after a
specified date.

         "Interest Payment Date", when used with respect to any Security, means
the Stated Maturity of an installment of interest on such Security.

         "Investment Company Act" means the Investment Company Act of 1940 and
any statute successor thereto, in each case as amended from time to time.

         "Last Sale Price" has the meaning specified in Section 1703.

         "Limited Vote Common Stock" means that number of shares of Common
Stock into which the outstanding shares of Limited Vote Common Stock are, upon
transfer, convertible at any time.

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

         "Notice of Default" means a written notice of the kind specified in
Section 501(4).

         "Offer" has the meaning specified in Section 1704(e).

         "Officer's Certificate" means a certificate signed by the Chairman of
the Board, a Vice Chairman of the Board, the President or a Vice President, of
the Company, and delivered to the Trustee. The officer signing the Company's
Officer's Certificate given pursuant to Section 1004 shall be the principal
executive, financial or accounting officer of the Company.

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

         "Original Issue Discount Security" means any Security which provides
for an amount less than the face principal amount thereof to be due and payable
upon a declaration of acceleration of the Maturity thereof pursuant to Section
502.

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

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

                                       4
<PAGE>   12

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

                  (3) Securities as to which Defeasance has been effected
         pursuant to Section 1502; and

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

provided, however, that in determining whether the Holders of the requisite
principal amount of the Outstanding Securities have given, made or taken any
request, demand, authorization, direction, notice, consent, waiver or other
action hereunder as of any date, (A) the principal amount of an Original Issue
Discount Security which shall be deemed to be Outstanding shall be the amount
of the principal thereof which would be due and payable as of such date upon
acceleration of the Maturity thereof to such date pursuant to Section 502, (B)
if, as of such date, the principal amount payable at the Stated Maturity of a
Security is not determinable, the principal amount of such Security which shall
be deemed to be Outstanding shall be the amount as specified or determined as
contemplated by Section 301, (C) the principal amount of a Security denominated
in one or more foreign currencies or currency units which shall be deemed to be
Outstanding shall be the U.S. dollar equivalent, determined as of such date in
the manner provided as contemplated by Section 301, of the principal amount of
such Security (or, in the case of a Security described in Clause (A) or (B)
above, of the amount determined as provided in such Clause), and (D) Securities
owned by the Company, or any other obligor upon the Securities or any Affiliate
of the Company, or of such other obligor shall be disregarded and deemed not to
be Outstanding, except that, in determining whether the Trustee shall be
protected in relying upon any such request, demand, authorization, direction,
notice, consent, waiver or other action, only Securities which the Trustee
knows to be so owned shall be so disregarded. Securities so owned which have
been pledged in good faith may be regarded as Outstanding if the pledgee
establishes to the satisfaction of the Trustee the pledgee's right so to act
with respect to such Securities and that the pledgee is not the Company, or any
other obligor upon the Securities or any Affiliate of the Company or of such
other obligor.

         "Paying Agent" means any Person authorized by the Company to pay the
principal of or any premium or interest on any Securities on behalf of the
Company.

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

         "Place of Payment", when used with respect to the Securities of any
series, means the place or places where the principal of and any premium and
interest on the Securities of that series are payable as specified as
contemplated by Section 301.

         "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



                                       5
<PAGE>   13

definition, any Security authenticated and delivered under Section 306 in
exchange for or in lieu of a mutilated, destroyed, lost or stolen Security
shall be deemed to evidence the same debt as the mutilated, destroyed, lost or
stolen Security.

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

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

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

         "Responsible Officer" means any officer in the corporate trust
department (or any successor thereto) of the Trustee, or any other officer of
the Trustee customarily performing functions similar to those performed by any
of such officers and also means, with respect to a particular corporate trust
matter, any other officer of the Trustee to whom such matter is referred
because of that officer's knowledge of and familiarity with that particular
matter.

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

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

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

         "Senior Debt" with respect to any series of Securities shall have the
meaning specified as contemplated by Section 301.

         "Senior Nonmonetary Default" has the meaning specified in Section
1204.

         "Senior Payment Default" has the meaning specified in Section 1204.

         "Significant Subsidiary" means, at any date of determination, any
Subsidiary that represents 10% or more of the Company's total consolidated
assets at the end of the most recent fiscal quarter for which financial
information is available or 10% or more of the Company's consolidated net
revenues or consolidated operating income for the most recent four quarters for
which financial information is available.

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

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

         "Subsidiary" of any Person means (1) a corporation more than 50% of
the combined voting power of the outstanding Voting Stock of which is owned,
directly or indirectly, by such Person or by



                                       6
<PAGE>   14

one or more other Subsidiaries of such Person or by such Person and one or more
Subsidiaries thereof or (2) any other Person (other than a corporation) in
which such Person, or one or more other Subsidiaries of such Person or such
Person and one or more other Subsidiaries thereof, directly or indirectly, has
at least a majority ownership and power to direct the policies, management and
affairs thereof.

         "Trading Day" has the meaning specified in Section 1703.

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

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

         "U.S. Government Obligation" has the meaning specified in Section 1504.

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

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

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

SECTION 102. Compliance Certificates and Opinions.

         Upon any application or request by the Company to the Trustee to take
any action under any provision of this Indenture, the Company, shall furnish to
the Trustee such certificates and opinions as may be required under the Trust
Indenture Act. Each such certificate or opinion shall be given in the form of
an Officer's Certificate, if to be given by an officer of the Company, or an
Opinion of Counsel, if to be given by counsel, and shall comply with the
requirements of the Trust Indenture Act and any other requirements set forth in
this Indenture.

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

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


                                       7
<PAGE>   15

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

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

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

SECTION 103. Form of Documents Delivered to Trustee.

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

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

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

SECTION 104. Acts of Holders; Record Dates.

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

         The fact and date of the execution by any Person of any such
instrument or writing may be proved by the affidavit of a witness of such
execution or by a certificate of a notary public or other officer authorized by
law to take acknowledgments of deeds, certifying that the individual signing
such instrument or writing acknowledged to him the execution thereof. Where
such execution is by a signer


                                       8
<PAGE>   16

acting in a capacity other than his individual capacity, such certificate or
affidavit shall also constitute sufficient proof of his authority. The fact and
date of the execution of any such instrument or writing, or the authority of
the Person executing the same, may also be proved in any other manner which the
Trustee deems sufficient.

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

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

         The Company may set any day as a record date for the purpose of
determining the Holders of Outstanding Securities of any series entitled to
give, make or take any request, demand, authorization, direction, notice,
consent, waiver or other action provided or permitted by this Indenture to be
given, made or taken by Holders of Securities of such series. If any record
date is set pursuant to this paragraph, the Holders of Outstanding Securities
of the relevant series on such record date, and no other Holders, shall be
entitled to take the relevant action, whether or not such Holders remain
Holders after such record date, provided that no such action shall be effective
hereunder unless taken on or prior to the applicable Expiration Date by Holders
of the requisite principal amount of Outstanding Securities of such series on
such record date. Nothing in this paragraph shall be construed to prevent the
Company from setting a new record date for any action for which a record date
has previously been set pursuant to this paragraph (whereupon the record date
previously set shall automatically and with no action by any Person be
cancelled and of no effect), and nothing in this paragraph shall be construed
to render ineffective any action taken by Holders of the requisite principal
amount of Outstanding Securities of the relevant series on the date such action
is taken. Promptly after any record date is set pursuant to this paragraph, the
Company, at its own expense, shall cause notice of such record date, the
proposed action by Holders and the applicable Expiration Date to be given to
the Trustee in writing and to each Holder of Securities of the relevant series
in the manner set forth in Section 106.

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

         Without limiting the foregoing, a Holder entitled hereunder to take
any action hereunder with regard to any particular Security may do so with
regard to all or any part of the principal amount of such Security or by one or
more duly appointed agents each of which may do so pursuant to such appointment
with regard to all or any part of such principal amount.

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

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


                                       9
<PAGE>   17


                  (1) the Trustee by any Holder or by the Company shall be
         sufficient for every purpose hereunder if made, given, furnished or
         filed in writing to or with the Trustee at its Corporate Trust Office,
         Attention: Capital Markets Fiduciary Services; or

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

         Notices to the Trustee shall be effective only upon receipt.

SECTION 106. Notice to Holders; Waiver.

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

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

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

SECTION 107. Conflict with Trust Indenture Act.

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

SECTION 108. Effect of Headings and Table of Contents.

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


                                      10
<PAGE>   18

SECTION 109. Successors and Assigns.

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

SECTION 110. Separability Clause.

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

SECTION 111. Benefits of Indenture.

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

SECTION 112. Governing Law.

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

SECTION 113. Legal Holidays.

         In any case where any Interest Payment Date, Redemption Date, purchase
date or Stated Maturity of any Security shall not be a Business Day at any
Place of Payment, then (notwithstanding any other provision of this Indenture
or of the Securities (other than a provision of any Security which specifically
states that such provision shall apply in lieu of this Section)) payment of
interest or principal (and premium, if any) need not be made at such Place of
Payment on such date, but may be made on the next succeeding Business Day at
such Place of Payment with the same force and effect as if made on the Interest
Payment Date, Redemption Date or purchase date, or at the Stated Maturity.

SECTION 114. Counterparts.

         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.

                                  ARTICLE TWO

                                 SECURITY FORMS


SECTION 201. Forms Generally.

         The Securities of each series shall be in substantially the form set
forth in this Article, or in such other form as shall be established by or
pursuant to a Board Resolution or in one or more indentures supplemental
hereto, in each case with such appropriate insertions, omissions, substitutions
and other variations as are required or permitted by this Indenture, and may
have such letters, numbers or other marks of identification and such legends or
endorsements placed thereon as may be required to comply with the rules of any
securities exchange or Depositary therefor or as may, consistently herewith, be
determined by the officers executing such Securities, as evidenced by their
execution thereof. If the form



                                      11
<PAGE>   19

of Securities of any series is established by action taken pursuant to a Board
Resolution, a copy of an appropriate record of such action shall be certified
by the Secretary or an Assistant Secretary of the Company and delivered to the
Trustee at or prior to the delivery of the Company Order contemplated by
Section 303 for the authentication and delivery of such Securities.

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

SECTION 202. Form of Face of Security.

         [Insert any legend required by the Internal Revenue Code and the
regulations thereunder.]


                                      12
<PAGE>   20

                             Quanta Services, Inc.

                                   ----------

No                                                              $
  -------------                                                  ---------------

         Quanta Services, Inc., a corporation duly organized and existing under
the laws of Delaware (herein called the "Company", which term includes any
successor Person under the Indenture hereinafter referred to), for value
received, hereby promises to pay to _________________________ , or registered
assigns, the principal sum of ______________________ Dollars
_______________________ on _______________________________________ [if the
Security is to bear interest prior to Maturity, insert -- , and to pay interest
thereon from _______________ or from the most recent Interest Payment Date to
which interest has been paid or duly provided for, semi-annually on
____________ and ____________ in each year, commencing _________, at the rate
of ____% per annum, until the principal hereof is paid or made available for
payment, provided that any principal and premium, and any such installment of
interest, which is overdue shall bear interest at the rate of ___% per annum
(to the extent that the payment of such interest shall be legally enforceable),
from the dates such amounts are due until they are paid or made available for
payment, and such interest shall be payable on demand. The interest so payable,
and punctually paid or duly provided for, on any Interest Payment Date will, as
provided in such Indenture, be paid to the Person in whose name this Security
(or one or more Predecessor Securities) is registered at the close of business
on the Regular Record Date for such interest, which shall be the _______ or
_______ (whether or not a Business Day), as the case may be, next preceding
such Interest Payment Date. Any such interest not so punctually paid or duly
provided for will forthwith cease to be payable to the Holder on such Regular
Record Date and may either be paid to the Person in whose name this Security
(or one or more Predecessor Securities) is registered at the close of business
on a Special Record Date for the payment of such Defaulted Interest to be fixed
by the Trustee, notice whereof shall be given to Holders of Securities of this
series not less than 10 days prior to such Special Record Date, or be paid at
any time in any other lawful manner not inconsistent with the requirements of
any securities exchange on which the Securities of this series may be listed,
and upon such notice as may be required by such exchange, all as more fully
provided in said Indenture].

         [If the Security is not to bear interest prior to Maturity or another
specified date, insert -- The principal of this Security shall not bear
interest [until __________] except in the case of a default in payment of
principal upon acceleration, upon redemption or at Stated Maturity and in such
case the overdue principal and any overdue premium shall bear interest at the
rate of _____% per annum (to the extent that the payment of such interest shall
be legally enforceable), from the dates such amounts are due until they are
paid or made available for payment. Interest on any overdue principal or
premium shall be payable on demand. Any such interest on overdue principal or
premium which is not paid on demand shall bear interest at the rate of _______%
per annum (to the extent that the payment of such interest on interest shall be
legally enforceable), from the date of such demand until the amount so demanded
is paid or made available for payment. Interest on any overdue interest shall
be payable on demand.]

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



                                      13
<PAGE>   21

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

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

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

Dated:


                                             Quanta Services, Inc.


                                             By
                                               ------------------------------



SECTION 203. Form of Reverse of Security.

         This Security is one of a duly authorized issue of securities of the
Company (herein called the "Securities"), issued and to be issued in one or
more series under a Subordinated Indenture, dated as of July 25, 2000 (herein
called the "Indenture", which term shall have the meaning assigned to it in
such instrument), between the Company and Chase Bank of Texas, National
Association, as Trustee (herein called the "Trustee", which term includes any
successor trustee under the Indenture), and reference is hereby made to the
Indenture for a statement of the respective rights, limitations of rights,
duties and immunities thereunder of the Company, the 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. This Security is
one of the series designated on the face hereof [if applicable, insert -- ,
limited in aggregate principal amount to $_______________].

         [If applicable, insert -- The Securities of this series are subject to
redemption upon not less than 30 days' notice by mail, [if applicable, insert
-- (1) on ____________ in any year commencing with the year ___________ and
ending with the year ______ through operation of the sinking fund for this
series at a Redemption Price equal to 100% of the principal amount, and (2)] at
any time [if applicable, insert -- on or after ___________, 20__], as a whole
or in part, at the election of the Company, at the following Redemption Prices
(expressed as percentages of the principal amount at Maturity): If redeemed [if
applicable, insert -- on or before _______________, ____%, and if redeemed]
during the 12-month period beginning _______________ of the years indicated,

<TABLE>
<CAPTION>

               Redemption                                     Redemption
Year           Price                  Year                    Price
----           ----------             ----                    ----------
<S>            <C>                    <C>                     <C>


</TABLE>




                                      14
<PAGE>   22
and thereafter at a Redemption Price equal to ______% of the principal amount
at Maturity, together in the case of any such redemption [if applicable, insert
-- (whether through operation of the sinking fund or otherwise)] with accrued
interest to the Redemption Date, but interest installments 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.]

          [if applicable, insert -- The Securities of this series are subject
to redemption upon not less than 30 days' notice by mail, (1) on _____________
in any year commencing with the year ______ and ending with the year _______
through operation of the sinking fund for this series at the Redemption Prices
for redemption through operation of the sinking fund (expressed as percentages
of the principal amount) set forth in the table below, and (2) at any time [if
applicable, insert -- on or after _______________], as a whole or in part, at
the election of the Company, at the Redemption Prices for redemption otherwise
than through operation of the sinking fund (expressed as percentages of the
principal amount) set forth in the table below: If redeemed during the 12-month
period beginning _______________ of the years indicated,

<TABLE>
<CAPTION>

                       Redemption Price
                        For Redemption                  Redemption Price For
                      Through Operation                 Redemption Otherwise
                           of the                       Than Through Operation
Year                     Sinking Fund                    of the Sinking Fund
----                  ------------------                ----------------------
<S>                   <C>                               <C>


</TABLE>


and thereafter at a Redemption Price equal to ______% of the principal amount
at Maturity, together in the case of any such redemption (whether through
operation of the sinking fund or otherwise) with accrued interest to the
Redemption Date, but interest installments 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.]

         [if applicable, insert -- Notwithstanding the foregoing, the Company
may not, prior to _____________, redeem any Securities of this series as
contemplated by [if applicable, insert -- Clause (2) of] the preceding
paragraph as a part of, or in anticipation of, any refunding operation by the
application, directly or indirectly, of moneys borrowed having an interest cost
to the Company (calculated in accordance with generally accepted financial
practice) of less than ________% per annum.]

         [if applicable, insert -- The sinking fund for this series provides
for the redemption on ____________ in each year beginning with the year
__________ and ending with the year ________ of [if applicable, insert -- not
less than $___________ ("mandatory sinking fund") and not more than]
$___________ aggregate principal amount of Securities of this series.
Securities of this series acquired or redeemed by the Company otherwise than
through [if applicable, insert -- mandatory] sinking fund payments may be
credited against subsequent [if applicable, insert -- mandatory] sinking fund



                                      15
<PAGE>   23

payments otherwise required to be made [if applicable, insert -- , in the
inverse order in which they become due].]

         [If the Security is subject to redemption of any kind, insert -- In
the event of redemption of this Security in part only, a new Security or
Securities of this series and of like tenor for the unredeemed portion hereof
will be issued in the name of the Holder hereof upon the cancellation hereof.]

         [If the Security is subject to conversion, insert -- Subject to the
provisions of the Indenture, each Holder has the right to convert the principal
amount of this Security into fully paid and nonassessable shares of Common
Stock of the Company at the initial Conversion Price per share of Common Stock
of $_____ (or $_____ in principal amount of Securities for each such share of
Common Stock), or at the adjusted Conversion Price then in effect, if
adjustment has been made as provided in the Indenture, upon surrender of the
Security to the Conversion Agent, together with a fully executed notice in
substantially the form attached hereto and, if required by the Indenture, an
amount equal to accrued interest payable on this Security.]

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

         [if applicable, insert -- The Indenture contains provisions for
Defeasance and Covenant Defeasance at any time of [the entire indebtedness of
this Security] [or] [certain restrictive covenants and Events of Default with
respect to this Security] [, in each case] upon compliance with certain
conditions set forth in the Indenture.]

         [If the Security is not an Original Issue Discount Security, insert --
If an Event of Default with respect to Securities of this series shall occur
and be continuing, the principal of the Securities of this series may be
declared due and payable in the manner and with the effect provided in the
Indenture.]

         [If the Security is an Original Issue Discount Security, insert -- If
an Event of Default with respect to Securities of this series shall occur and
be continuing, an amount of principal of the Securities of this series may be
declared due and payable in the manner and with the effect provided in the
Indenture. Such amount shall be equal to -- insert formula for determining the
amount. Upon payment (i) of the amount of principal so declared due and payable
and (ii) of interest on any overdue principal, premium and interest (in each
case to the extent that the payment of such interest shall be legally
enforceable), all of the Company's obligations in respect of the payment of the
principal of and premium and interest, if any, on the Securities of this series
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 of each series to be
affected under the Indenture at any time by the Company and the Trustee with
the consent of the Holders of a majority in principal amount of the Securities
at the time Outstanding of each series to be affected. The Indenture also
contains provisions permitting the Holders of specified percentages in
principal amount of the Securities of each series at the time Outstanding, on
behalf of the Holders of all Securities of such series, 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


                                      16
<PAGE>   24

and upon all future Holders of this Security and of any Security issued upon
the registration of transfer hereof or in exchange herefor or in lieu hereof,
whether or not notation of such consent or waiver is made upon this Security.

         As provided in and subject to the provisions of the Indenture, the
Holder of this Security shall not have the right to institute any proceeding
with respect to the Indenture or for the appointment of a receiver or trustee
or for any other remedy thereunder, unless such Holder shall have previously
given the Trustee written notice of a continuing Event of Default with respect
to the Securities of this series, the Holders of not less than 25% in principal
amount of the Securities of this series at the time Outstanding shall have made
written request to the Trustee to institute proceedings in respect of such
Event of Default as Trustee and offered the Trustee reasonable indemnity, and
the Trustee shall not have received from the Holders of a majority in principal
amount of Securities of this series at the time 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 or any
premium or interest hereon on or after the respective due dates expressed
herein.

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

         As provided in the Indenture and subject to certain limitations
therein set forth, the transfer of this Security is registrable in the Security
Register, upon surrender of this Security for registration of transfer at the
office or agency of the Company in any place where the principal of and any
premium and interest on this Security are payable, duly endorsed by, or
accompanied by a written instrument of transfer in form satisfactory to the
Company and the Security Registrar duly executed by, the Holder hereof or his
attorney duly authorized in writing, and thereupon one or more new Securities
of this series and of like tenor, of authorized denominations and for the same
aggregate principal amount, will be issued to the designated transferee or
transferees.

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

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

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

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

SECTION 204. [intentionally omitted].



                                      17
<PAGE>   25

SECTION 205. Form of Legend for Global Securities.

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

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

SECTION 206. Form of Trustee's Certificate of Authentication.

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

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

                                      CHASE BANK OF TEXAS, NATIONAL ASSOCIATION
                                                                     As Trustee

Date of Authentication:                                By
                       ----------------------------      -----------------------
                                                          Authorized Signatory

SECTION 207. Form of Conversion Notice.

         Each convertible Security shall have attached thereto, or set forth on
the reverse of the Security, a notice of conversion in substantially the
following form:

                               Conversion Notice

                           To: Quanta Services, Inc.

                  The undersigned owner of this Security hereby: (i)
         irrevocably exercises the option to convert this Security, or the
         portion hereof below designated, for shares of Common Stock of Quanta
         Services, Inc. in accordance with the terms of the Indenture referred
         to in this Security and (ii) directs that such shares of Common Stock
         deliverable upon the conversion, together with any check in payment
         for fractional shares and any Security(ies) representing any
         unconverted principal amount hereof, be issued and delivered to the
         registered holder hereof unless a different name has been indicated
         below. If shares are to be delivered registered in the name of a
         person other than the undersigned, the undersigned will pay all
         transfer taxes payable with respect thereto. Any amount required to be
         paid by the undersigned on account of interest accompanies this
         Security.

                  Dated
                       -------------------------------------



                                      18
<PAGE>   26

                                                        Signature

         Fill in for registration of shares if to be delivered, and of
Securities if to be issued, otherwise than to and in the name of the registered
holder.


                                              ---------------------------------
                                                   Social Security or other
                                                Taxpayer Identification Number
----------------------------------
              (Name)

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

----------------------------------
  (City, State and Zip Code)
(Please print name and address)
                                       Principal amount to be converted:
                                       (if less than all)

                                       $
                                        ---------------------------------------
Signature Guarantee*

----------

*Participant in a recognized Signature Guarantee Medallion Program (or other
signature acceptable to the Trustee).


                                 ARTICLE THREE

                                 THE SECURITIES


SECTION 301. Amount Unlimited; Issuable in Series.

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

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

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

                  (2) [intentionally omitted];

                  (3) any change to the subordination provisions which applies
         to the Securities of the series from those contained in Article Twelve
         with respect to the Securities, and the definitions of Senior Debt and
         Designated Senior Debt which shall apply to the Securities of the
         series;



                                      19
<PAGE>   27

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

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

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

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

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

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

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

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

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

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

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



                                      20
<PAGE>   28

         the terms and conditions upon which such election is to be made and
         the amount so payable (or the manner in which such amount shall be
         determined);

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

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

                  (17) if applicable, that the Securities of the series, in
         whole or any specified part, shall be defeasible pursuant to Section
         1502 or Section 1503 or both such Sections and, if other than by a
         Board Resolution, the manner in which any election by the Company to
         defease such Securities shall be evidenced;

                  (18) if applicable, that any Securities of the series shall
         be issuable in whole or in part in the form of one or more Global
         Securities and, in such case, the respective Depositories for such
         Global Securities, the form of any legend or legends which shall be
         borne by any such Global Security in addition to or in lieu of that
         set forth in Section 205 and any circumstances in addition to or in
         lieu of those set forth in Clause (2) of the last paragraph of Section
         305 in which any such Global Security may be exchanged in whole or in
         part for Securities registered, and any transfer of such Global
         Security in whole or in part may be registered, in the name or names
         of Persons other than the Depositary for such Global Security or a
         nominee thereof;

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

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

                  (21) whether the Securities of the series will be convertible
         into Common Stock (or cash in lieu thereof) and, if so, the terms and
         conditions upon which such conversion shall be effected including the
         initial Conversion Price and any adjustments thereto in addition to or
         different from those set forth in Section 1704, the conversion period
         and other provisions in addition to or in lieu of those set forth
         herein; and

                  (22) any other terms of the series (which terms shall not be
         inconsistent with the provisions of this Indenture, except as
         permitted by Section 901(5)).

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



                                      21
<PAGE>   29

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

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

SECTION 302. Denominations.

         The Securities of each series shall be issuable only in registered
form without coupons and only in such denominations as shall be specified as
contemplated by Section 301. In the absence of any such specified denomination
with respect to the Securities of any series, the Securities of such series
shall be issuable in denominations of $1,000 and any integral multiple thereof.

SECTION 303. Execution, Authentication, Delivery and Dating.

         The Securities shall be executed on behalf of the Company by its
Chairman of the Board, its Vice Chairman of the Board, its President or one of
its Vice Presidents, under its corporate seal reproduced thereon. The signature
of any of these officers on the Securities may be manual or facsimile.

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

         At any time and from time to time after the execution and delivery of
this Indenture, the Company may deliver Securities of any series executed by
the Company to the Trustee for authentication, together with a Company Order
for the authentication and delivery of such Securities, and the Trustee in
accordance with the Company Order shall authenticate and deliver such
Securities. If the form or terms of the Securities of the series have been
established by or pursuant to one or more Board Resolutions as permitted by
Sections 201 and 301, in authenticating such Securities, and accepting the
additional responsibilities under this Indenture in relation to such
Securities, the Trustee shall be entitled to receive, and (subject to Section
601) shall be fully protected in relying upon, an Opinion of Counsel stating,

                  (1) if the form of such Securities has been established by or
         pursuant to Board Resolution as permitted by Section 201, that such
         form has been established in conformity with the provisions of this
         Indenture;

                  (2) if the terms of such Securities have been established by
         or pursuant to Board Resolution as permitted by Section 301, that such
         terms have been established in conformity with the provisions of this
         Indenture; and

                  (3) that such Securities, when authenticated and delivered by
         the Trustee and issued by the Company in the manner and subject to any
         limitations, exceptions and conditions specified in such Opinion of
         Counsel, will constitute valid and legally binding obligations of the
         Company, enforceable in accordance with their terms, subject to
         bankruptcy, insolvency, fraudulent transfer, reorganization,
         moratorium and similar laws of general applicability relating to or
         affecting creditors' rights and to general equity principles.



                                      22
<PAGE>   30

If such form or terms have been so established, the Trustee shall not be
required to authenticate such Securities if the issue of such Securities
pursuant to this Indenture will affect the Trustee's own rights, duties or
immunities under the Securities and this Indenture or otherwise in a manner
which is not reasonably acceptable to the Trustee.

         Notwithstanding the provisions of Section 301 and of the preceding
paragraph, if all Securities of a series are not to be originally issued at one
time, it shall not be necessary to deliver the Officer's Certificate otherwise
required pursuant to Section 301 or the Company Order and Opinion of Counsel
otherwise required pursuant to such preceding paragraph at or prior to the
authentication of each Security of such series if such documents are delivered
at or prior to the authentication upon original issuance of the first Security
of such series to be issued.

         Each Security shall be dated the date of its authentication.

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

SECTION 304. Temporary Securities.

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

         If temporary Securities of any series are issued, the Company will
cause definitive Securities of that series to be prepared without unreasonable
delay. After the preparation of definitive Securities of such series, the
temporary Securities of such series shall be exchangeable for definitive
Securities of such series upon surrender of the temporary Securities of such
series at the office or agency of the Company in a Place of Payment for that
series, without charge to the Holder. Upon surrender for cancellation of any
one or more temporary Securities of any series, the Company shall execute and
the Trustee shall authenticate and deliver in exchange therefor one or more
definitive Securities of the same series, of any authorized denominations and
of like tenor and aggregate principal amount. Until so exchanged, the temporary
Securities of any series shall in all respects be entitled to the same benefits
under this Indenture as definitive Securities of such series and tenor.

SECTION 305. Registration, Registration of Transfer and Exchange.

         The Company shall cause to be kept at the Corporate Trust Office of
the Trustee a register (the register maintained in such office and in any other
office or agency of the Company in a Place of Payment being herein sometimes
collectively referred to as the "Security Register") in which, subject to



                                      23
<PAGE>   31

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

         Upon surrender for registration of transfer of any Security of a
series at the office or agency of the Company in a Place of Payment for that
series, the Company shall execute and the Trustee shall authenticate and
deliver, in the name of the designated transferee or transferees, one or more
new Securities of the same series, of any authorized denominations and of like
tenor and aggregate principal amount.

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

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

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

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

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

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

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

                  (2) Notwithstanding any other provision in this Indenture, no
         Global Security may be exchanged in whole or in part for Securities
         registered, and no transfer of a Global Security in whole or in part
         may be registered, in the name of any Person other than the Depositary
         for such Global Security or a nominee thereof, or a successor
         Depositary or a nominee thereof, unless (A) such Depositary (i) has
         notified the Company that it is unwilling or unable to continue as



                                      24
<PAGE>   32

         Depositary for such Global Security and no successor Depositary has
         been appointed within 90 days thereof or (ii) has ceased to be a
         clearing agency registered under the Exchange Act and no successor
         Depositary has been appointed within 90 days thereof, (B) there shall
         have occurred and be continuing an Event of Default with respect to
         such Global Security and the Security Registrar shall have received a
         written request from such Depositary to issue certificated Securities
         or (C) there shall exist such circumstances, if any, in addition to or
         in lieu of the foregoing as have been specified for this purpose as
         contemplated by Section 301.

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

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

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

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

         If there shall be delivered to the Company and the Trustee (i)
evidence to their satisfaction of the destruction, loss or theft of any
Security and (ii) such security or indemnity as may be required by them to save
each of them and any agent of either of them harmless, then, in the absence of
notice to the Company or the Trustee that such Security has been acquired by a
bona fide purchaser, the Company shall execute and the Trustee shall
authenticate and deliver, in lieu of any such destroyed, lost or stolen
Security, a new Security of the same series and of like tenor and principal
amount and bearing a number not contemporaneously outstanding. If, after the
delivery of such replacement Security, a bona fide purchaser of the original
Security in lieu of which such replacement Security was issued presents for
payment or registration such original Security, the Trustee shall be entitled
to recover such replacement Security from the person to whom it was delivered
or any person taking therefrom, except a bona fide purchaser, and shall be
entitled to recover upon the security or indemnity provided therefor to the
extent of any loss, damage, cost or expense incurred by the Company, the
Trustee or any Authenticating Agent in connection therewith.

         In case any such mutilated, destroyed, lost or stolen Security has
become or is about to become due and payable or is to be converted, the Company
in its discretion may, instead of issuing a new Security, pay or authorize the
conversion of such Security (without surrender thereof save in the case of a
mutilated Security).

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



                                      25
<PAGE>   33

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

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

SECTION 307. Payment of Interest; Interest Rights Preserved.

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

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

                  (1) The Company may elect to make payment of any Defaulted
         Interest to the Persons in whose names the Securities of such series
         (or their respective Predecessor Securities) are registered at the
         close of business on a Special Record Date for the payment of such
         Defaulted Interest, which shall be fixed in the following manner. The
         Company shall notify the Trustee in writing of the amount of Defaulted
         Interest proposed to be paid on each Security of such series and the
         date of the proposed payment, and at the same time the Company shall
         deposit with the Trustee an amount of money equal to the aggregate
         amount proposed to be paid in respect of such Defaulted Interest or
         shall make arrangements satisfactory to the Trustee for such deposit
         prior to the date of the proposed payment, such money when deposited
         to be held in trust for the benefit of the Persons entitled to such
         Defaulted Interest as in this Clause provided. Thereupon the Trustee
         shall fix a Special Record Date for the payment of such Defaulted
         Interest which shall be not more than 15 days and not less than 10
         days prior to the date of the proposed payment and not less than 10
         days after the receipt by the Trustee of the notice of the proposed
         payment. The Trustee shall promptly notify the Company of such Special
         Record Date and, in the name and at the expense of the Company, shall
         cause notice of the proposed payment of such Defaulted Interest and
         the Special Record Date therefor to be given to each Holder of
         Securities of such series in the manner set forth in Section 106, not
         less than 10 days prior to such Special Record Date. Notice of the
         proposed payment of such Defaulted Interest and the Special Record
         Date therefor having been so mailed, such Defaulted Interest shall be
         paid to the Persons in whose names the Securities of such series (or
         their respective Predecessor Securities) are registered at the close
         of business on such Special Record Date and shall no longer be payable
         pursuant to the following Clause (2).

                  (2) The Company may make payment of any Defaulted Interest on
         the Securities of any series in any other lawful manner not
         inconsistent with the requirements of any securities exchange on which
         such Securities may be listed, and upon such notice as may be required
         by


                                      26
<PAGE>   34

         such exchange, if, after notice given by the Company to the Trustee of
         the proposed payment pursuant to this Clause, such manner of payment
         shall be deemed practicable by the Trustee.

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

SECTION 308. Persons Deemed Owners.

         Prior to due presentment of a Security for registration of transfer,
the Company, the Trustee and any agent of the Company or the Trustee may treat
the Person in whose name such Security is registered as the owner of such
Security for the purpose of receiving payment of principal of and any premium
and (subject to Section 307) any interest on such Security and for all other
purposes whatsoever, whether or not such Security be overdue, and neither the
Company, the Trustee nor any agent of the Company or the Trustee shall be
affected by notice to the contrary.

SECTION 309. Cancellation.

         All Securities surrendered for payment, redemption, purchase,
conversion, registration of transfer or exchange or for credit against any
sinking fund payment shall, if surrendered to any Person other than the
Trustee, be delivered to the Trustee and shall be promptly cancelled by it. The
Company may at any time deliver to the Trustee for cancellation any Securities
previously authenticated and delivered hereunder which the Company may have
acquired in any manner whatsoever, and may deliver to the Trustee (or to any
other Person for delivery to the Trustee) for cancellation any Securities
previously authenticated hereunder which the Company has not issued and sold,
and all Securities so delivered shall be promptly cancelled by the Trustee. No
Securities shall be authenticated in lieu of or in exchange for any Securities
cancelled as provided in this Section, except as expressly permitted by this
Indenture. All cancelled Securities held by the Trustee shall be disposed of as
directed by a Company Order and otherwise shall be treated in accordance with
the Trustee's document retention policies.

SECTION 310. Computation of Interest.

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


                                  ARTICLE FOUR

                           SATISFACTION AND DISCHARGE

SECTION 401. Satisfaction and Discharge of Indenture.

         This Indenture shall upon Company Request cease to be of further
effect (except as to any surviving rights of registration of transfer or
exchange of Securities herein expressly provided for), and the Trustee, at the
expense of the Company, shall execute proper instruments acknowledging
satisfaction and discharge of this Indenture, when

         (1) either



                                      27
<PAGE>   35

                  (A) all Securities theretofore authenticated and delivered
         (other than (i) Securities which have been destroyed, lost or stolen
         and which have been replaced, converted or paid as provided in Section
         306 and (ii) 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 1003) have been delivered to the Trustee for
         cancellation; or

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

                           (i) have become due and payable, or

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

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

         and the Company, in the case of (i), (ii) or (iii) above, has
         deposited or caused to be deposited with the Trustee as trust funds in
         trust for the purpose money in an amount sufficient to pay and
         discharge the entire indebtedness on such Securities not theretofore
         delivered to the Trustee for cancellation, for principal and any
         premium 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 Officer's Certificate
         and an Opinion of Counsel, each stating that all conditions precedent
         herein provided for relating to the satisfaction and discharge of this
         Indenture have been complied with.

         Notwithstanding the satisfaction and discharge of this Indenture, the
obligations of the Company to the Trustee under Section 607, the obligations of
the Trustee to any Authenticating Agent under Section 614 and, if money shall
have been deposited with the Trustee pursuant to subclause (B) of Clause (1) of
this Section, the obligations of the Trustee under Section 402 and the last
paragraph of Section 1003 shall survive.

SECTION 402. Application of Trust Money.

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



                                      28
<PAGE>   36

                                  ARTICLE FIVE

                                    REMEDIES


SECTION 501. Events of Default.

         "Event of Default", wherever used herein with respect to Securities of
any series, means any one of the following events (whatever the reason for such
Event of Default and whether it shall be occasioned by the provisions of
Article Twelve 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 any premium
         on any Security of that series at its Maturity, whether or not
         prohibited by the provisions of Article Twelve; or

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

                  (3) default in the deposit of any sinking fund payment, when
         and as due by the terms of a Security of that series, whether or not
         prohibited by the provisions of Article Twelve; 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 whose performance or whose breach is elsewhere
         in this Section specifically dealt with or which has expressly been
         included in this Indenture solely for the benefit of series of
         Securities other than that series), and continuance of such default or
         breach for a period of 60 days after there has been given, by
         registered or certified mail, to the Company by the Trustee or to the
         Company and the Trustee by the Holders of at least 25% in principal
         amount of the Outstanding Securities of that series a written notice
         specifying such default or breach and requiring it to be remedied and
         stating that such notice is a "Notice of Default" hereunder; or

                  (5) default in the performance, or breach, of the provisions
         of Article Eight;

                  (6) [intentionally omitted];

                  (7) the entry by a court having jurisdiction in the premises
         of (A) a decree or order for relief in respect of the Company, any
         Significant Subsidiary or any group of Subsidiaries that together
         would constitute a 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, any Significant Subsidiary or any group
         of Subsidiaries that together would constitute a 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, any Significant
         Subsidiary or any group of Subsidiaries that together would constitute
         a 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, any Significant
         Subsidiary or any group of Subsidiaries that together would constitute
         a Significant Subsidiary or of any substantial part of its or their
         property, or ordering the winding up or liquidation of its or their
         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



                                      29
<PAGE>   37

                  (8) the commencement by the Company, any Significant
         Subsidiary or any group of Subsidiaries that together would constitute
         a Significant Subsidiary of a voluntary case or proceeding under any
         applicable Federal or State bankruptcy, insolvency, reorganization or
         other similar law or of any other case or proceeding to be adjudicated
         a bankrupt or insolvent, or the consent by it or them to the entry of
         a decree or order for relief in respect of the Company, any
         Significant Subsidiary or any group of Subsidiaries that together
         would constitute a Significant Subsidiary in an involuntary case or
         proceeding under any applicable Federal or State bankruptcy,
         insolvency, reorganization or other similar law or to the commencement
         of any bankruptcy or insolvency case or proceeding against it or them,
         or the filing by it or them of a petition or answer or consent seeking
         reorganization or relief under any applicable Federal or State law, or
         the consent by it or them 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, any Significant Subsidiary or any group of
         Subsidiaries that together would constitute a Significant Subsidiary
         or of any substantial part of its or their property, or the making by
         it or them of an assignment for the benefit of creditors, or the
         admission by it or them in writing of its or their inability to pay
         its or their debts generally as they become due, or the taking of
         corporate action by the Company, any Significant Subsidiary or any
         group of Subsidiaries that together would constitute a Significant
         Subsidiary in furtherance of any such action; or

                  (9) any other Event of Default provided with respect to
         Securities of that series.

SECTION 502. Acceleration of Maturity; Rescission and Annulment.

         If an Event of Default (other than an Event of Default specified in
Section 501(7) or 501(8)) with respect to Securities of any series at the time
Outstanding shall occur and be continuing, then in every such case the Trustee
or the Holders of not less than 25% in principal amount of the Outstanding
Securities of that series may declare the principal amount of all the
Securities of that series (or, if any Securities of that series are Original
Issue Discount Securities, or if the principal amount thereof is not then
determinable, such portion of the principal amount of such Securities, or such
other amount in lieu of such principal amount, as may be specified by the terms
thereof) to be due and payable immediately, by a notice in writing to the
Company (and to the Trustee if given by Holders), and upon any such declaration
such principal amount (or specified amount) shall become immediately due and
payable. If an Event of Default specified in Section 501(7) or 501 (8) with
respect to Securities of any series at the time Outstanding shall occur, the
principal amount of all the Securities of that series (or, if any Securities of
that series are Original Issue Discount Securities, or if the principal amount
thereof is not then determinable, such portion of the principal amount of such
Securities, or such other amount in lieu of such principal amount, as may be
specified by the terms thereof) shall automatically, and without any
declaration or other action on the part of the Trustee or any Holder, become
immediately due and payable.

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

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

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



                                      30
<PAGE>   38

                           (B) the principal of (and premium, if any, on) any
                  Securities of that series which have become due otherwise
                  than by such declaration of acceleration and any interest
                  thereon at the rate or rates prescribed therefor in such
                  Securities,

                           (C) to the extent that payment of such interest is
                  lawful, interest upon overdue interest at the rate or rates
                  prescribed therefor in such Securities, and

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

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

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


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

         The Company covenants that if

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

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

the Company will, upon demand of the Trustee, 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 any premium and interest and, to the extent that
payment of such interest shall be legally enforceable, interest on any overdue
principal and premium and on any overdue interest, at the rate or rates
prescribed therefor in such Securities, and, in addition thereto, such further
amount as shall be sufficient to cover the costs and expenses of collection,
including the compensation, expenses, disbursements and advances of the
Trustee, its agents and counsel.

         If an Event of Default with respect to Securities of any series 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 of such series
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.



                                      31
<PAGE>   39

SECTION 504. Trustee May File Proofs of Claim.

         In case of any judicial proceeding relative to the Company, or any
other obligor upon the Securities, or the property or creditors of the Company,
or any other obligor upon the Securities, the Trustee shall be entitled and
empowered, by intervention in such proceeding or otherwise, to take any and all
actions authorized under the Trust Indenture Act in order to have claims of the
Holders and the Trustee allowed in any such proceeding. In particular, the
Trustee shall be authorized to collect and receive any moneys or other property
payable or deliverable on any such claims and to distribute the same; and any
custodian, receiver, assignee, trustee, liquidator, sequestrator or other
similar official in any such judicial proceeding is hereby authorized by each
Holder to make such payments to the Trustee and, in the event that the Trustee
shall consent to the making of such payments directly to the Holders, to pay to
the Trustee any amount due it for the compensation, expenses, disbursements and
advances of the Trustee, its agents and counsel, and any other amounts due the
Trustee under Section 607.

         No provision of this Indenture shall be deemed to authorize the
Trustee to authorize or consent to or accept or adopt on behalf of any Holder
any plan of reorganization, arrangement, adjustment or composition affecting
the Securities or the rights of any Holder thereof or to authorize the Trustee
to vote in respect of the claim of any Holder in any such proceeding; provided,
however, that the Trustee may, on behalf of the Holders, vote for the election
of a trustee in bankruptcy or similar official and be a member of a creditors'
or other similar committee.

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

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

SECTION 506. Application of Money Collected.

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

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

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

SECTION 507. Limitation on Suits.

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



                                      32
<PAGE>   40

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

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

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

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

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

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

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

         Notwithstanding any other provision in this Indenture, the Holder of
any Security shall have the right, which is absolute and unconditional, to
receive payment of the principal of and any premium and (subject to Section
307) interest on such Security on the respective Stated Maturities expressed in
such Security (or, in the case of redemption or offer by the Company to
purchase the Securities pursuant to the terms of this Indenture, on the
Redemption Date or purchase date, as applicable), or, if applicable, to convert
such Security as provided in Article Seventeen, and to institute suit for the
enforcement of any such payment or for the enforcement of any such right to
convert, and such rights shall not be impaired without the consent of such
Holder.

SECTION 509. Restoration of Rights and Remedies.

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

SECTION 510. Rights and Remedies Cumulative.

         Except as otherwise provided with respect to the replacement or
payment of mutilated, destroyed, lost or stolen Securities in the last
paragraph of Section 306, no right or remedy herein conferred upon or reserved
to the Trustee or to the Holders is intended to be exclusive of any other right
or remedy, and


                                      33
<PAGE>   41


every right and remedy shall, to the extent permitted by law, be cumulative and
in addition to every other right and remedy given hereunder or now or hereafter
existing at law or in equity or otherwise. The assertion or employment of any
right or remedy hereunder, or otherwise, shall not prevent the concurrent
assertion or employment of any other appropriate right or remedy.

SECTION 511. Delay or Omission Not Waiver.

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

SECTION 512. Control by Holders.

         The Holders of a majority in principal amount of the Outstanding
Securities of any series shall have the right to direct the time, method and
place of conducting any proceeding for any remedy available to the Trustee, or
exercising any trust or power conferred on the Trustee, with respect to the
Securities of such series, 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.

SECTION 513. Waiver of Past Defaults.

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

                  (1) in the payment of the principal of or any premium or
         interest on any Security of such series (including any Security which
         is required to have been purchased by the Company pursuant to an offer
         to purchase by the Company made pursuant to the terms of this
         Indenture), or

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

                                      34
<PAGE>   42

SECTION 514. Undertaking for Costs.

         In any suit for the enforcement of any right or remedy under this
Indenture, or in any suit against the Trustee for any action taken, suffered or
omitted by it as Trustee, a court may require any party litigant in such suit
to file an undertaking to pay the costs of such suit, and may assess costs
against any such party litigant, in the manner and to the extent provided in
the Trust Indenture Act; provided that neither this Section nor the Trust
Indenture Act shall be deemed to authorize any court to require such an
undertaking or to make such an assessment in any suit instituted by the
Company.

SECTION 515. Waiver of Usury, Stay or Extension Laws.

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


                                  ARTICLE SIX

                                  THE TRUSTEE


SECTION 601. Certain Duties and Responsibilities.

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

SECTION 602. Notice of Defaults.

If a default occurs hereunder with respect to Securities of any series, the
Trustee shall give the Holders of Securities of such series notice of such
default as and to the extent provided by the Trust Indenture Act; provided,
however, that in the case of any default of the character specified in Section
501(4) with respect to Securities of such series, no such notice to Holders
shall be given until at least 30 days after the occurrence thereof. For the
purpose of this Section, the term "default" means any event which is, or after
notice or lapse of time or both would become, an Event of Default with respect
to Securities of such series.



                                      35
<PAGE>   43

SECTION 603. Certain Rights of Trustee.

Subject to the provisions of Section 601:

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

                  (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 herein specifically prescribed) may,
         in the absence of bad faith on its part, rely upon an Officer's
         Certificate;

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

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

                  (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, other evidence of indebtedness
         or other paper or document, but the Trustee, in its discretion, may
         make such further inquiry or investigation into such facts or matters
         as it may see fit, and, if the Trustee shall determine to make such
         further inquiry or investigation, it shall be entitled to examine the
         books, records and premises of the Company, personally or by agent or
         attorney;

                  (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;

                  (8) the Trustee is not required to take notice or deemed to
         have notice of any default or Event of Default hereunder, except
         Events of Default under Section 501, subsections (1), (2) and (3),
         unless a Responsible Officer of the Trustee has actual knowledge
         thereof or has received notice in writing of such default or Event of
         Default from the Company or the Holders of at least 25% in aggregate
         principal amount of the Outstanding Securities, and in the absence of
         any such notice, the Trustee may conclusively assume that no such
         default or Event of Default exists;

                  (9) the Trustee is not required to give any bond or surety
         with respect to the performance of its duties or the exercise of its
         powers under this Indenture;



                                      36
<PAGE>   44

                  (10) in the event the Trustee receives inconsistent or
         conflicting requests and indemnity from two or more groups of Holders
         of Securities, each representing less than a majority in aggregate
         principal amount of the Securities Outstanding, pursuant to the
         provisions of this Indenture, the Trustee, in its sole discretion, may
         determine what action, if any, shall be taken;

                  (11) the Trustee's immunities and protections from liability
         and its right to indemnification in connection with the performance of
         its duties under this Indenture shall extend to the Trustee's
         officers, directors, agents, attorneys and employees. Such immunities
         and protections and right to indemnification, together with the
         Trustee's right to compensation, shall survive the Trustee's
         resignation or removal, the defeasance or discharge of this Indenture
         and final payment of the Securities;

                  (12) the permissive right of the Trustee to take the actions
         permitted by this Indenture shall not be construed as an obligation or
         duty to do so; and

                  (13) except for information provided by the Trustee
         concerning the Trustee, the Trustee shall have no responsibility for
         any information in any offering memorandum or other disclosure
         material distributed with respect to the Securities, and the Trustee
         shall have no responsibility for compliance with any state or federal
         securities laws in connection with the Securities.

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

         The recitals contained herein and in the Securities, except the
Trustee's certificates of authentication, shall be taken as the statements of
the Company, and neither the Trustee nor any Authenticating Agent assumes any
responsibility for their correctness. The Trustee makes no representations as
to the validity or sufficiency of this Indenture or of the Securities. Neither
the Trustee nor any Authenticating Agent shall be accountable for the use or
application by the Company of Securities or the proceeds thereof.

SECTION 605. May Hold Securities.

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

SECTION 606. Money Held in Trust.

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

SECTION 607. Compensation and Reimbursement.

         The Company agrees

                                      37
<PAGE>   45

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

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

                  (3) to indemnify the Trustee for, and to hold it harmless
         against, any loss, liability or expense incurred without negligence or
         willful misconduct on its part, arising out of or in connection with
         the acceptance or administration of the trust or trusts hereunder,
         including the costs and expenses of defending itself against any claim
         or liability in connection with the exercise or performance of any of
         its powers or duties hereunder. When the Trustee incurs expenses or
         renders services after the occurrence of an Event of Default specified
         in paragraph (7) or (8) of Section 501 of this Indenture, such
         expenses and the compensation for such services are intended to
         constitute expenses of administration under any Insolvency or
         Liquidation Proceeding. For the purposes of this paragraph,
         "Insolvency or Liquidation Proceeding" means, with respect to any
         Person, (a) an insolvency or bankruptcy case or proceeding, or any
         receivership, liquidation, reorganization or similar case or
         proceeding in connection therewith, relative to such Person or its
         creditors, as such, or its assets, or (b) any liquidation, dissolution
         or other winding-up proceeding of such Person, 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 such Person.

SECTION 608. Conflicting Interests.

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

SECTION 609. Corporate Trustee Required; Eligibility.

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



                                      38
<PAGE>   46
SECTION 610. Resignation and Removal; Appointment of Successor.

         No resignation or removal of the Trustee and no appointment of a
successor Trustee pursuant to this Article shall become effective until the
acceptance of appointment by the successor Trustee in accordance with the
applicable requirements of Section 611.

         The Trustee may resign at any time with respect to the Securities of
one or more series by giving written notice thereof to the Company. If the
instrument of acceptance by a successor Trustee required by Section 611 shall
not have been delivered to the Trustee within 30 days after the giving of such
notice of resignation, the resigning Trustee may petition any court of
competent jurisdiction for the appointment of a successor Trustee with respect
to the Securities of such series.

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

         If at any time:

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

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

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

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

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



                                      39
<PAGE>   47
petition any court of competent jurisdiction for the appointment of a successor
Trustee with respect to the Securities of such series.

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

SECTION 611.  Acceptance of Appointment by Successor.

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

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

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


                                       40
<PAGE>   48

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

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

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

SECTION 613.  Preferential Collection of Claims Against Company .

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

SECTION 614.  Appointment of Authenticating Agent.

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

         Any Person into which an Authenticating Agent may be merged or
converted or with which it may be consolidated, or any Person resulting from any
merger, conversion or consolidation to which such Authenticating Agent shall be
a party, or any Person succeeding to the corporate agency or corporate trust
business of an Authenticating Agent, shall continue to be an Authenticating
Agent, provided such


                                       41
<PAGE>   49

Person shall be otherwise eligible under this Section, without the execution or
filing of any paper or any further act on the part of the Trustee or the
Authenticating Agent.

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

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

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

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

                                       CHASE BANK OF TEXAS, NATIONAL ASSOCIATION
                                                                      As Trustee

Date of authentication:                           By
                       ---------------              ---------------------------
                                                       Authenticating Agent

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




                                  ARTICLE SEVEN

                HOLDERS' LISTS AND REPORTS BY TRUSTEE AND COMPANY

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

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

                  (1) semi-annually, not later than March 1 and September 1 in
         each year, a list, in such form as the Trustee may reasonably require,
         of the names and addresses of the Holders of Securities of each series
         as of the preceding February 15 or August 15, as the case may be, and


                                       42
<PAGE>   50

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

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

SECTION 702.  Preservation of Information; Communications to Holders.

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

         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 privileges of the Trustee, shall be as provided by the Trust
Indenture Act.

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

SECTION 703.  Reports by Trustee.

         The term "reporting date" as used in this Section means May 15 of each
year. Within 60 days after the reporting date in each year beginning in 2001,
the Trustee shall transmit to Holders such reports concerning the Trustee and
its actions under this Indenture as may be required pursuant to the Trust
Indenture Act at the times and in the manner provided pursuant thereto.

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

SECTION 704.  Reports by Company.

         The Company shall file with the Trustee and the Commission, and
transmit to Holders, such information, documents and other reports, and such
summaries thereof, as may be required pursuant to the Trust Indenture Act at the
times and in the manner provided pursuant to such Act; provided that any such
information, documents or reports required to be filed with the Commission
pursuant to Section 13 or 15(d) of the Exchange Act shall be filed with the
Trustee within 15 days after the same is so required to be filed with the
Commission.


                                       43
<PAGE>   51


                                  ARTICLE EIGHT

              CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE

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

         The Company shall not, in a single transaction or a series of related
transactions, consolidate with or merge into any other Person or permit any
other Person to consolidate with or merge into the Company or transfer, convey,
sell, lease or otherwise dispose of all or substantially all of its assets,
unless:

                  (1) in a transaction in which the Company does not survive or
         in which the Company transfers, conveys, sells, leases or otherwise
         disposes of all or substantially all of its assets, the successor
         entity (for purposes of this Article Eight, a "Successor Company")
         shall be a corporation, partnership, trust or other entity organized
         and validly existing under the laws of the United States of America,
         any State thereof or the District of Columbia, and 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 and any premium and interest on all the
         Securities and the performance or observance of every covenant of this
         Indenture on the part of the Company to be performed or observed;

                  (2) immediately after giving effect to such transaction and
         treating any indebtedness which becomes an obligation of the Company or
         any Subsidiary as a result of such transaction as having been incurred
         by the Company or such Subsidiary at the time of such transaction, no
         Event of Default, and no event which, after notice or lapse of time or
         both, would become an Event of Default, shall have happened and be
         continuing;

                  (3) any other conditions provided pursuant to Section 301 with
         respect to the Securities of a series are satisfied; and (4) the
         Company has delivered to the Trustee an Officer's Certificate and an
         Opinion of Counsel, each stating that such consolidation, merger or
         disposition 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.

SECTION 802.  [intentionally omitted]

SECTION 803.  Successor Substituted.

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


                                  ARTICLE NINE

                             SUPPLEMENTAL INDENTURES


SECTION 901.  Supplemental Indentures Without Consent of Holders.


                                       44
<PAGE>   52

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

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

                  (2) to add to the covenants of the Company for the benefit of
         the Holders of all or any series of Securities (and if such covenants
         are to be for the benefit of less than all series of Securities,
         stating that such covenants are expressly being included solely for the
         benefit of such series) or to surrender any right or power herein
         conferred upon the Company; or

                  (3) to add any additional Events of Default for the benefit of
         the Holders of all or any series of Securities (and if such additional
         Events of Default are to be for the benefit of less than all series of
         Securities, stating that such additional Events of Default are
         expressly being included solely for the benefit of such series); or

                  (4) to add to or change any of the provisions of this
         Indenture to such extent as shall be necessary to permit or facilitate
         the issuance of Securities in bearer form, registrable or not
         registrable as to principal, and with or without interest coupons, or
         to permit or facilitate the issuance of Securities in uncertificated
         form; or

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

                  (6) to secure the Securities; or

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

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

                  (9) to cure any ambiguity, to correct or supplement any
         provision herein which may be defective or inconsistent with any other
         provision herein, or to make any other provisions with respect to
         matters or questions arising under this Indenture, provided that such
         action pursuant to this Clause (9) shall not adversely affect the
         interests of the Holders of Securities of any series in any material
         respect; or

                  (10) [intentionally omitted]; or

                  (11) to provide for adjustment of conversion rights pursuant
         to Section 1705 hereof.


                                       45
<PAGE>   53


SECTION 902.  Supplemental Indentures With Consent of Holders.


         With the consent of the Holders of not less than a majority in
principal amount of the Outstanding Securities of each series affected by such
supplemental indenture, by Act of said Holders delivered to the Company, and the
Trustee, 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 of such series under this Indenture; provided, however,
that no such supplemental indenture shall, without the consent of the Holder of
each Outstanding Security affected thereby,

                  (1) change the Stated Maturity of the principal of, or any
         installment of principal of or interest on, any Security, or reduce the
         principal amount thereof or the rate of interest thereon or any premium
         payable upon the redemption thereof, or reduce the amount of the
         principal of an Original Issue Discount Security or any other Security
         which would be due and payable upon a declaration of acceleration of
         the Maturity thereof pursuant to Section 502, or change any Place of
         Payment where, or the coin or currency in which, any Security or any
         premium or interest thereon is payable, or impair the right to
         institute suit for the enforcement of (a) any such payment on or after
         the Stated Maturity thereof (or, in the case of redemption, on or after
         the Redemption Date or in the case of an offer to purchase Securities
         which has been made pursuant to a covenant contained in this Indenture,
         on or after the applicable purchase date) or (b) any conversion right
         with respect to any Security, or modify the provisions of this
         Indenture with respect to (x) the subordination of the Securities or
         (y) the conversion of the Securities, in either case in a manner
         adverse to the Holders; or

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

                  (3) modify any of the provisions of this Section, Section 502,
         Section 513 or Section 1009, except to increase any such percentage or
         to provide that certain other provisions of this Indenture cannot be
         modified or waived without the consent of the Holder of each
         Outstanding Security affected thereby; provided, however, that this
         clause shall not be deemed to require the consent of any Holder with
         respect to changes in the references to "the Trustee" and concomitant
         changes in this Section and Section 1009, or the deletion of this
         proviso, in accordance with the requirements of Sections 611 and
         901(8); or

                  (4) following the making of an offer to purchase Securities
         which has been made pursuant to a covenant contained in this Indenture,
         modify the provisions of this Indenture with respect to such offer to
         purchase in a manner adverse to such Holder.

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


                                       46
<PAGE>   54

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

SECTION 903.  Execution of Supplemental Indentures.

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

SECTION 904.  Effect of Supplemental Indentures.

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

SECTION 905.  Conformity with Trust Indenture Act.

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

SECTION 906.  Reference in Securities to Supplemental Indentures.

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


                                   ARTICLE TEN

                                    COVENANTS

SECTION 1001. Payment of Principal, Premium and Interest.

         The Company covenants and agrees for the benefit of each series of
Securities that it will duly and punctually pay the principal of and any premium
and interest on the Securities of that series in accordance with the terms of
the Securities and this Indenture. Principal, premium, if any, and interest
shall be considered paid on the date due if the Paying Agent, if other than the
Company, holds as of 11:00 a.m. New York time on the due date money deposited by
the Company in immediately available funds and designated for and sufficient to
pay all principal, premium, if any, and interest then due, unless such payment
is prohibited by the provisions of Article Twelve.

                                       47
<PAGE>   55

SECTION 1002. Maintenance of Office or Agency.

         The Company will maintain in each Place of Payment for any series of
Securities an office or agency where Securities of that series may be presented
or surrendered for payment or, if applicable, for conversion, where Securities
of that series may be surrendered for registration of transfer or exchange and
where notices and demands to or upon the Company in respect of the Securities of
that series and this Indenture may be served. The Company will give prompt
written notice to the Trustee of the location, and any change in the location,
of such office or agency. If at any time the Company shall fail to maintain any
such required office or agency or shall fail to furnish the Trustee with the
address thereof, such presentations, surrenders, notices and demands may be made
or served at the Corporate Trust Office of the Trustee, and the Company hereby
appoints the Trustee as its agent to receive all such presentations, surrenders,
notices and demands.

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

SECTION 1003. Money for Securities Payments to Be Held in Trust.

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

         Whenever the Company shall have one or more Paying Agents for any
series of Securities, it will, prior to each due date of the principal of or any
premium or interest on any Securities of that series, deposit with a Paying
Agent a sum sufficient to pay such amount, such sum to be held as provided by
the Trust Indenture Act, and (unless such Paying Agent is the Trustee) the
Company will promptly notify the Trustee of its action or failure so to act.

         The Company will cause each Paying Agent for any series of Securities
other than the Trustee to execute and deliver to the Trustee an instrument in
which such Paying Agent shall agree with the Trustee, subject to the provisions
of this Section, that such Paying Agent will (1) comply with the provisions of
the Trust Indenture Act applicable to it as a Paying Agent and (2) during the
continuance of any default by the Company, or any other obligor upon the
Securities of that series in the making of any payment in respect of the
Securities of that series, upon the written request of the Trustee, forthwith
pay to the Trustee all sums held in trust by such Paying Agent for payment in
respect of the Securities of that series.

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

                                       48
<PAGE>   56

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 or any premium or
interest on any Security of any series and remaining unclaimed for two years
after such principal, premium or interest has become due and payable shall be
paid to the Company on Company Request, or (if then held by the Company) shall
be discharged from such trust; and the Holder of such Security shall thereafter,
as an unsecured general creditor, look only to the Company for payment thereof,
and all liability of the Trustee or such Paying Agent with respect to such trust
money, and all liability of the Company as trustee thereof, shall thereupon
cease; provided, however, that the Trustee or such Paying Agent, before being
required to make any such repayment, may at the expense of the Company cause to
be published once, in a newspaper published in the English language, customarily
published on each Business Day and of general circulation in The City of New
York, New York, notice that such money remains unclaimed and that, after a date
specified therein, which shall not be less than 30 days from the date of such
publication, any unclaimed balance of such money then remaining will be repaid
to the Company.

SECTION 1004. Statement by Officers as to Default.

         (a) The Company will deliver to the Trustee, within 90 days after the
end of each fiscal year of the Company ending after the date hereof, an
Officer's Certificate, stating whether or not to the best knowledge of the
signers thereof the Company, is in default in the performance and observance of
any of the terms, provisions and conditions of this Indenture (without regard to
any period of grace or requirement of notice provided hereunder) and, if the
Company shall be in default, specifying all such defaults and the nature and
status thereof of which they may have knowledge.

         (b) The Company shall deliver to the Trustee, as soon as possible and
in any event within five days after the Company becomes aware of the occurrence
of an Event of Default or an event which, with notice or the lapse of time or
both, would constitute an Event of Default, an Officer's Certificate setting
forth the details of such Event of Default or default, and the action which the
Company proposes to take with respect thereto.

SECTION 1005. Existence.

         Subject to Article Eight, the Company will do or cause to be done all
things necessary to preserve and keep in full force and effect the existence,
rights (charter and statutory) and franchises of the Company; provided, however,
that the Company shall not be required to preserve any such right or franchise
if the Board of Directors shall determine that the preservation thereof is no
longer desirable in the conduct of the business of the Company and that the loss
thereof is not disadvantageous in any material respect to the Holders.

                                       49
<PAGE>   57

SECTION 1006. Maintenance of Properties.

         The Company will cause all properties used or useful in the conduct of
its business or the business of any 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 Subsidiary and not disadvantageous in any material respect to
the Holders.

SECTION 1007. Payment of Taxes and Other Claims.

         The Company will pay or discharge or cause to be paid or discharged,
before the same shall become delinquent, (1) all taxes, assessments and
governmental charges levied or imposed upon the Company or any Subsidiary or
upon the income, profits or property of the Company or any Subsidiary, and (2)
all lawful claims for labor, materials and supplies which, if unpaid, might by
law become a lien upon the property of the Company or any Subsidiary; provided,
however, that the Company shall not be required to pay or discharge or cause to
be paid or discharged any such tax, assessment, charge or claim whose amount,
applicability or validity is being contested in good faith by appropriate
proceedings.

SECTION 1008. Maintenance of Insurance.

         The Company shall, and shall cause its Subsidiaries to, keep at all
times all of their properties which are of an insurable nature insured against
loss or damage with insurers believed by the Company to be responsible to the
extent that property of similar character is usually so insured by corporations
similarly situated and owning like properties in accordance with good business
practice.

SECTION 1009. Waiver of Certain Covenants.

         Except as otherwise specified as contemplated by Section 301 or Section
902 for Securities of such series, the Company may, with respect to the
Securities of any series, omit in any particular instance to comply with any
term, provision or condition set forth in any covenant provided pursuant to
Section 301(22), 901(2) or 901(7) for the benefit of the Holders of such series
if before the time for such compliance the Holders of at least a majority in
principal amount of the Outstanding Securities of such series shall, by Act of
such Holders, either waive such compliance in such instance or generally waive
compliance with such term, provision or condition, but no such waiver shall
extend to or affect such term, provision or condition except to the extent so
expressly waived, and, until such waiver shall become effective, the obligations
of the Company and the duties of the Trustee in respect of any such term,
provision or condition shall remain in full force and effect.


                                 ARTICLE ELEVEN

                            REDEMPTION OF SECURITIES


SECTION 1101. Applicability of Article.


                                       50
<PAGE>   58

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

SECTION 1102. Election to Redeem; Notice to Trustee.

         The election of the Company to redeem any Securities shall be evidenced
by a Board Resolution or in another manner specified as contemplated by Section
301 for such Securities. In case of any redemption at the election of the
Company of less than all the Securities of any series (including any such
redemption affecting only a single Security), the Company shall, at least 45
days prior to the Redemption Date fixed by the Company (unless a shorter notice
shall be satisfactory to the Trustee), notify the Trustee of such Redemption
Date, of the principal amount of Securities of such series to be redeemed and,
if applicable, of the tenor of the Securities to be redeemed. In the case of any
redemption of Securities prior to the expiration of any restriction on such
redemption provided in the terms of such Securities or elsewhere in this
Indenture, the Company shall furnish the Trustee with an Officer's Certificate
evidencing compliance with such restriction.

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

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

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

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

         For all purposes of this Indenture, unless the context otherwise
requires, all provisions relating to the redemption of Securities shall relate,
in the case of any Securities redeemed or to be redeemed only in part, to the
portion of the principal amount of such Securities which has been or is to be
redeemed. If any Security selected for partial redemption is surrendered for
conversion after such selection, the converted portion of such Security shall be
deemed (so far as may be) to be the portion selected for redemption. Upon any
redemption of less than all the Securities of a series, for purposes of
selection for redemption the Company and the Trustee may treat as Outstanding
Securities surrendered for conversion during the


                                       51
<PAGE>   59

period of 15 days next preceding the mailing of a notice of redemption, and need
not treat as Outstanding any Security authenticated and delivered during such
period in exchange for the unconverted portion of any Security converted in part
during such period.

SECTION 1104. Notice of Redemption.

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

         All notices of redemption shall state:

                  (1) the Redemption Date;

                  (2) the Redemption Price;

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

                  (4) that on the Redemption Date the Redemption Price will
         become due and payable upon each such Security to be redeemed and, if
         applicable, that interest thereon will cease to accrue on and after
         said date (unless the Company shall default on such payment);

                  (5) the place or places where each such Security is to be
         surrendered for payment of the Redemption Price;

                  (6) that the redemption is for a sinking fund, if such is the
         case; and

                  (7) if applicable, the Conversion Price then in effect and the
         date on which the right to convert the Securities or portions thereof
         to be redeemed will expire (unless the Company shall default on such
         payment).

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

SECTION 1105. Deposit of Redemption Price.

         On or prior to any Redemption Date, the Company shall deposit with the
Trustee or with a Paying Agent (or, if the Company is acting as its own Paying
Agent, segregate and hold in trust as provided in Section 1003) an amount of
money sufficient to pay the Redemption Price of, and (except if the Redemption
Date shall be an Interest Payment Date) accrued interest on, all the Securities
which are to be redeemed on that date. If any Security called for redemption is
converted pursuant hereto, any money deposited with the Trustee or any Paying
Agent or so segregated and held in trust for the redemption of such Security
shall be paid to the Company upon delivery of a Company Request to the Trustee
or such Paying Agent, or, if then held by the Company, shall be discharged from
such trust.


                                       52
<PAGE>   60

SECTION 1106. Securities Payable on Redemption Date.

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

         If any Security called for redemption shall not be so paid upon
surrender thereof for redemption, the principal and any premium shall, until
paid, bear interest from the Redemption Date at the rate prescribed therefor in
the Security and, if applicable, shall continue to be convertible.

SECTION 1107.  Securities Redeemed in Part.

         Any Security which is to be redeemed only in part shall be surrendered
at a Place of Payment therefor (with, if the Company or the Trustee so requires,
due endorsement by, or a written instrument of transfer in form satisfactory to
the Company and the Trustee duly executed by, the Holder thereof or his attorney
duly authorized in writing), and the Company shall execute and the Trustee shall
authenticate and deliver to the Holder of such Security without service charge,
a new Security or Securities of the same series and of like tenor, 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.


                                 ARTICLE TWELVE

                           SUBORDINATION OF SECURITIES

SECTION 1201. Applicability of Article.

         Unless otherwise provided with respect to the Securities of any series
in or pursuant to the Board Resolution or supplemental indenture establishing
such series of Securities pursuant to Section 301, the provisions of this
Article shall be applicable to each series of Securities.

SECTION 1202. Securities Subordinate to Senior Debt.

         The Company covenants and agrees, and each Holder of a Security, by his
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 Four and Article Fifteen), the payment of the principal of (and premium,
if any) and interest on each and all of the Securities of such series are hereby
expressly made subordinate and subject in right of payment to the prior payment
in full of all Senior Debt of the Company.

         No provisions of this Article Twelve shall prevent the occurrence of
any Event of Default.

                                       53
<PAGE>   61

SECTION 1203. Payment Over of Proceeds Upon Dissolution, Etc.

         In the event of (a) any insolvency or bankruptcy case or proceeding, or
any receivership, liquidation, reorganization or other similar case or
proceeding in connection therewith, relative to the Company or to its creditors,
as such, or to its assets, or (b) any liquidation, dissolution or other winding
up of the Company, whether voluntary or involuntary and whether or not involving
insolvency or bankruptcy, or (c) any assignment for the benefit of creditors or
any other marshalling of assets and liabilities of the Company, then and in any
such event specified in (a), (b) or (c) above (each such event, if any, herein
sometimes referred to as a "Proceeding") the holders of Senior Debt of the
Company shall be entitled to receive payment in full of all amounts due or to
become due on or in respect of all Senior Debt of the Company, or provision
shall be made for such payment in cash or cash equivalents or otherwise in a
manner satisfactory to the holders of Senior Debt of the Company, before the
Holders of the Securities are entitled to receive any payment or distribution of
any kind or character, whether in cash, property or securities (including any
payment or distribution which may be payable or deliverable by reason of the
payment of any other Debt of the Company subordinated to the payment of the
Securities, such payment or distribution being hereinafter referred to as a
"Junior Subordinated Payment"), on account of principal of (or premium, if any)
or interest on the Securities or on account of any purchase or other acquisition
of Securities by the Company or any Subsidiary of the Company (all such
payments, distributions, purchases and acquisitions, other than the payment or
distribution of stock or securities of the Company referred to in the second
succeeding paragraph, herein referred to, individually and collectively, as a
"Securities Payment"), and to that end the holders of Senior Debt of the Company
shall be entitled to receive, for application to the payment thereof, any
Securities Payment which may be payable or deliverable in respect of the
Securities in any such Proceeding.

         In the event that, notwithstanding the foregoing provisions of this
Section, the Trustee or the Holder of any Security shall have received any
Securities Payment before all Senior Debt of the Company is paid in full or
payment thereof provided for in cash or cash equivalents or otherwise in a
manner satisfactory to the holders of Senior Debt of the Company, and if such
fact shall, at or prior to the time of such Securities Payment, have been made
known to the Trustee or, as the case may be, such Holder, then and in such event
such Securities Payment 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 of the Company remaining unpaid,
to the extent necessary to pay all Senior Debt of the Company in full, after
giving effect to any concurrent payment or distribution to or for the holders of
Senior Debt of the Company.

         For purposes of this Article only, the words "any payment or
distribution of any kind or character, whether in cash, property or securities"
shall not be deemed to include a payment or distribution of stock or securities
of the Company provided for by a plan of reorganization or readjustment
authorized by an order or decree of a court of competent jurisdiction in a
reorganization proceeding under any applicable bankruptcy law or of any other
corporation provided for by such plan of reorganization or readjustment which
stock or securities are subordinated in right of payment to all then outstanding
Senior Debt of the Company to substantially the same extent as 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 all or substantially all of its properties and assets as an entirety to
another Person upon the terms and conditions set forth in Article Eight shall
not be deemed a Proceeding for the purposes of this Section if the Person formed
by such consolidation or into which the Company is merged or the Person which
acquires by conveyance or transfer such properties and assets as an entirety, as
the case may be,


                                       54
<PAGE>   62

shall, as a part of such consolidation, merger, conveyance or transfer, comply
with the conditions set forth in Article Eight.

SECTION 1204. No Payment When Senior Debt of the Company in Default.

         In the event that any Senior Payment Default (as defined below) shall
have occurred and be continuing, then no Securities Payment shall be made unless
and until such Senior Payment Default shall have been cured or waived or shall
have ceased to exist or all amounts then due and payable in respect of Senior
Debt of the Company shall have been paid in full, or provision shall have been
made for such payment in cash or cash equivalents or otherwise in a manner
satisfactory to the holders of Senior Debt of the Company; provided, however,
that nothing in this Section shall prevent the satisfaction of any sinking fund
payment in accordance with Article Sixteen by delivering and crediting pursuant
to Section 1602 Securities which have been acquired (upon redemption or
otherwise) prior to such Senior Payment Default.

         "Senior Payment Default" means any default in the payment of principal
of (or premium, if any) or interest on any Senior Debt of the Company when due,
whether at the Stated Maturity of any such payment or by declaration of
acceleration, call for redemption or otherwise.

         In the event that any Senior Nonmonetary Default (as defined below)
shall have occurred and be continuing, then, upon the receipt by the Company and
the Trustee of written notice of such Senior Nonmonetary Default from any
holder, or agent for the holders, of the Designated Senior Debt which is the
subject of such Senior Nonmonetary Default, no Securities Payment shall be made
during the period (the "Payment Blockage Period") commencing on the date of such
receipt of such written notice and ending on the earlier of (i) the date on
which such Senior Nonmonetary Default shall have been cured or waived or shall
have ceased to exist or all Designated Senior Debt that is the subject of such
Senior Nonmonetary Default shall have been discharged; (ii) the 179th day after
the date of such receipt of such written notice; and (iii) the date on which the
Payment Blockage Period shall have been terminated by written notice to the
Company or the Trustee from the agent for the Designated Senior Debt initiating
the Payment Blockage Period; provided, however, that nothing in this Section
shall prevent the satisfaction of any sinking fund payment in accordance with
Article Sixteen by delivering and crediting pursuant to Section 1602 Securities
which have been acquired (upon redemption or otherwise) prior to the date of
such receipt of such written notice. No more than one Payment Blockage Period
may be commenced with respect to the Securities during any 360-day period and
there shall be a period of at least 181 consecutive days in each 360-day period
when no Payment Blockage Period is in effect. For all purposes of this
paragraph, no Senior Payment Default or Senior Nonmonetary Default that existed
or was continuing on the date of commencement of any Payment Blockage Period
shall be, or be made, the basis for the commencement of a subsequent Payment
Blockage Period, whether or not within a period of 360 consecutive days, unless
such Senior Payment Default or Senior Nonmonetary Default shall have been cured
for a period of not less than 90 consecutive days.

         "Senior Nonmonetary Default" means the occurrence or existence and
continuance of any event of default with respect to any Designated Senior Debt,
other than a Senior Payment Default, permitting the holders of such Designated
Senior Debt (or a trustee or agent on behalf of the holders thereof) to declare
such Designated Senior Debt due and payable prior to the date on which it would
otherwise become due and payable.

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


                                       55
<PAGE>   63

may be, such Holder, then and in such event such Securities Payment shall be
paid over and delivered forthwith to the holders of Senior Debt (or a trustee or
agent on their behalf).

         The provisions of this Section shall not apply to any Securities
Payment with respect to which Section 1203 would be applicable.

SECTION 1205. 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 Proceeding referred to in Section 1203 or under the
conditions described in Section 1204, from making Securities Payments, or (b)
the application by the Trustee of any money deposited with it hereunder to
Securities Payments or the retention of such Securities Payment by the Holders,
if, at the time of such application by the Trustee, it did not have knowledge
that such Securities Payment would have been prohibited by the provisions of
this Article.

SECTION 1206. Subrogation to Rights of Holders of Senior Debt of the Company.

         Subject to the payment in full of all amounts due or to become due on
or in respect of Senior Debt of the Company, or the provision for such payment
in cash or cash equivalents or otherwise in a manner satisfactory to the holders
of Senior Debt of the Company, the Holders of the Securities shall be subrogated
to the rights of the holders of such Senior Debt of the Company to receive
payments and distributions of cash, property and securities applicable to the
Senior Debt of the Company 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
the Company 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 of the Company by Holders of the Securities or the
Trustee, shall, as among the Company, its creditors other than holders of Senior
Debt of the Company 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 of the
Company.

SECTION 1207. 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 on the one hand and the
holders of Senior Debt of the Company on the other hand. Nothing contained in
this Article or elsewhere in this Indenture or in the Securities is intended to
or shall (a) impair, as among the Company, its creditors other than holders of
Senior Debt of the Company and the Holders of the Securities, the obligation of
the Company, which is absolute and unconditional (and which, subject to the
rights under this Article of the holders of Senior Debt of the Company, is
intended to rank equally with all other general obligations of the Company), to
pay to the Holders of the Securities the principal of (and premium, if any) and
interest on the Securities as and when the same shall become due and payable in
accordance with their terms; or (b) affect the relative rights against the
Company of the Holders of the Securities and creditors of the Company other than
the holders of Senior Debt of the Company; or (c) 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 of the Company to receive cash,
property and securities otherwise payable or deliverable to the Trustee or such
Holder.

                                       56
<PAGE>   64

SECTION 1208. Trustee to Effectuate Subordination.

         Each Holder of a Security by his acceptance thereof authorizes and
directs the Trustee on his behalf to take such action as may be necessary or
appropriate to effectuate the subordination provided in this Article and
appoints the Trustee his attorney-in-fact for any and all such purposes.

SECTION 1209. No Waiver of Subordination Provisions.

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

         Without in any way limiting the generality of the foregoing paragraph,
the holders of Senior Debt of the Company 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 of the Company, 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 of the Company, or otherwise amend or supplement in any
manner Senior Debt of the Company or any instrument evidencing the same or any
agreement under which Senior Debt of the Company is outstanding; (ii) sell,
exchange, release or otherwise deal with any property pledged, mortgaged or
otherwise securing Senior Debt of the Company; (iii) release any Person liable
in any manner for the collection of Senior Debt of the Company; and (iv)
exercise or refrain from exercising any rights against the Company and any other
Person.

SECTION 1210. 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; provided, however, that failure to provide
such notice shall not affect the subordination of the Securities provided for
herein. 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 the Trustee shall have received
written notice thereof from the Company or a holder of Senior Debt of the
Company or from any trustee therefor; and, prior to the receipt of any such
written notice, the Trustee, subject to the provisions of Section 601, 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 at least three 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 three
Business Days prior to such date.

         Subject to the provisions of Section 601, the Trustee shall be entitled
to rely on the delivery to it of a written notice by a Person representing
himself to be a holder of Senior Debt of the Company (or a trustee or other
representative therefor) to establish that such notice has been given by a
holder of Senior Debt of the Company (or a trustee therefor). In the event that
the Trustee determines in good faith that further evidence is required with
respect to the right of any Person as a holder of Senior Debt of the


                                       57
<PAGE>   65
Company 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 of the Company 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 1211. 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 601, 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 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 of
the Company 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 1212. Trustee Not Fiduciary for Holders of Senior Debt of the Company.

         The Trustee shall not be deemed to owe any fiduciary duty to the
holders of Senior Debt of the Company 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 of the Company shall be entitled
by virtue of this Article or otherwise.

SECTION 1213. Rights of Trustee as Holder of Senior Debt of the Company;
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 of the Company
which may at any time be held by it, to the same extent as any other holder of
Senior Debt of the Company, 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 607.

SECTION 1214. 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 1213 shall not apply to the Company, or any Affiliate of
the Company if it or such Affiliate acts as Paying Agent.


                                       58
<PAGE>   66

SECTION 1215. Defeasance of this Article Twelve.

         The subordination of the Securities of a series provided by this
Article Twelve is expressly made subject to the provisions for satisfaction and
discharge in Article Four and the provisions for defeasance or covenant
defeasance in Article Fifteen hereof and, anything herein to the contrary
notwithstanding, upon the effectiveness of any such satisfaction and discharge,
defeasance or covenant defeasance, the Securities of such series then
outstanding shall thereupon cease to be subordinated pursuant to this Article
Twelve.


                                ARTICLE THIRTEEN

                             [intentionally omitted]


                                ARTICLE FOURTEEN

                             [intentionally omitted]


                                 ARTICLE FIFTEEN

                       DEFEASANCE AND COVENANT DEFEASANCE

SECTION 1501. Company's Option to Effect Defeasance or Covenant Defeasance.

         The Company may elect, at its option at any time, to have Section 1502
or Section 1503 applied to any Securities or any series of Securities, as the
case may be, designated pursuant to Section 301 as being defeasible pursuant to
such Section 1502 or 1503, in accordance with any applicable requirements
provided pursuant to Section 301 and upon compliance with the conditions set
forth below in this Article. Any such election shall be evidenced in or pursuant
to a Board Resolution or in another manner specified as contemplated by Section
301 for such Securities.

SECTION 1502. Defeasance and Discharge.

         Upon the Company's exercise of its option (if any) to have this Section
applied to any Securities or any series of Securities, as the case may be, the
Company shall be deemed to have been discharged from its obligations and the
provisions of Article Twelve shall cease to be effective, with respect to such
Securities as provided in this Section on and after the date the conditions set
forth in Section 1504 are satisfied (hereinafter called "Defeasance"). For this
purpose, such Defeasance means that the Company shall be deemed to have paid and
discharged the entire indebtedness represented by such Securities and to have
satisfied all its other obligations under such Securities and this Indenture
insofar as such Securities are concerned (and the Trustee, at the expense of the
Company, shall execute proper instruments acknowledging the same), subject to
the following which shall survive until otherwise terminated or discharged
hereunder: (1) the rights of Holders of such Securities to receive, solely from
the trust fund described in Section 1504 and as more fully set forth in such
Section, payments in respect of the principal of and any premium and interest on
such Securities when payments are due, or to convert such Securities in
accordance with the provisions of Article Seventeen, (2) the Company's
obligations with respect to such Securities under Sections 304, 305, 306, 1002
and 1003 and, if applicable, Article Seventeen, (3) the rights, powers, trusts,
duties and immunities of the Trustee hereunder, and (4) this Article. Subject to
compliance with this Article, the Company may exercise its option (if any) to
have


                                       59
<PAGE>   67

this Section applied to any Securities notwithstanding the prior exercise of its
option (if any) to have Section 1503 applied to such Securities.

SECTION 1503. Covenant Defeasance.

         Upon the Company's exercise of its option (if any) to have this Section
applied to any Securities or any series of Securities, as the case may be, (1)
the Company shall be released from its obligations under Section 801(3),
Sections 1006 through 1008, inclusive, and any covenants provided pursuant to
Section 301(22), 901(2), or 901(7) for the benefit of the Holders of such
Securities, and (2) the occurrence of any event specified in Sections 501(4)
(with respect to any of Section 801(3), Sections 1006 through 1008, inclusive,
and any such covenants provided pursuant to Section 301(22), 901(2), or 901(7)),
and 501(9) shall be deemed not to be or result in an Event of Default and (3)
the provisions of Article Twelve shall cease to be effective, in each case with
respect to such Securities as provided in this Section on and after the date the
conditions set forth in Section 1504 are satisfied (hereinafter called "Covenant
Defeasance"). For this purpose, such Covenant Defeasance means that, with
respect to such Securities, the Company may omit to comply with and shall have
no liability in respect of any term, condition or limitation set forth in any
such specified Section (to the extent so specified in the case of Section
501(4)) or Article Twelve, whether directly or indirectly by reason of any
reference elsewhere herein to any such Section or Article or by reason of any
reference in any such Section or Article to any other provision herein or in any
other document, but the remainder of this Indenture and such Securities shall be
unaffected thereby.

SECTION 1504. Conditions to Defeasance or Covenant Defeasance.

         The following shall be the conditions to the application of Section
1502 or Section 1503 to any Securities or any series of Securities, as the case
may be:

                  (1) The Company shall irrevocably have deposited or caused to
         be deposited with the Trustee (or another trustee which satisfies the
         requirements contemplated by Section 609 and agrees to comply with the
         provisions of this Article applicable to it) as trust funds in trust
         for the purpose of making the following payments, specifically pledged
         as security for, and dedicated solely to, the benefits of the Holders
         of such Securities, (A) money in an amount, or (B) U.S. Government
         Obligations which through the scheduled payment of principal and
         interest in respect thereof in accordance with their terms will
         provide, not later than one day before the due date of any payment,
         money in an amount, or (C) a combination thereof, in each case
         sufficient, in the opinion of a nationally recognized firm of
         independent public accountants expressed in a written certification
         thereof delivered to the Trustee, to pay and discharge, and which shall
         be applied by the Trustee (or any such other qualifying trustee) to pay
         and discharge, the principal of and any premium and interest on such
         Securities on the respective Stated Maturities or Redemption Date, in
         accordance with the terms of this Indenture and such Securities. As
         used herein, "U.S. Government Obligation" means (x) any security which
         is (i) a direct obligation of the United States of America for the
         payment of which the full faith and credit of the United States of
         America is pledged or (ii) an obligation of a Person controlled or
         supervised by and acting as an agency or instrumentality of the United
         States of America the payment of which is unconditionally guaranteed as
         a full faith and credit obligation by the United States of America,
         which, in either case (i) or (ii), is not callable or redeemable at the
         option of the issuer thereof, and (y) any depositary receipt issued by
         a bank (as defined in Section 3(a)(2) of the Securities Act) as
         custodian with respect to any U.S. Government Obligation which is
         specified in Clause (x) above and held by such bank for the account of
         the holder of such depositary receipt, or with respect to any specific
         payment of principal of or interest on any U.S. Government Obligation


                                       60
<PAGE>   68


         which is so specified and held, provided that (except as required by
         law) such custodian is not authorized to make any deduction from the
         amount payable to the holder of such depositary receipt from any amount
         received by the custodian in respect of the U.S. Government Obligation
         or the specific payment of principal or interest evidenced by such
         depositary receipt.

                  (2) In the event of an election to have Section 1502 apply to
         any Securities or any series of Securities, as the case may be, the
         Company shall have delivered to the Trustee an Opinion of Counsel
         stating that (A) the Company has received from, or there has been
         published by, the United States Internal Revenue Service a ruling or
         (B) since the date of this instrument, there has been a change in the
         applicable Federal income tax law, in either case (A) or (B) to the
         effect that, and based thereon such opinion shall confirm that, the
         Holders of such Securities will not recognize gain or loss for Federal
         income tax purposes as a result of the deposit, Defeasance and
         discharge to be effected with respect to such Securities and will be
         subject to Federal income tax on the same amount, in the same manner
         and at the same times as would be the case if such deposit, Defeasance
         and discharge were not to occur.

                  (3) In the event of an election to have Section 1503 apply to
         any Securities or any series of Securities, as the case may be, the
         Company shall have delivered to the Trustee an Opinion of Counsel to
         the effect that the Holders of such Securities will not recognize gain
         or loss for Federal income tax purposes as a result of the deposit and
         Covenant Defeasance to be effected with respect to such Securities and
         will be subject to Federal income tax on the same amount, in the same
         manner and at the same times as would be the case if such deposit and
         Covenant Defeasance were not to occur.

                  (4) The Company shall have delivered to the Trustee an
         Officer's Certificate to the effect that neither such Securities nor
         any other Securities of the same series, if then listed on any
         securities exchange, will be delisted as a result of such deposit.

                  (5) No event which is, or after notice or lapse of time or
         both would become, an Event of Default with respect to such Securities
         or any other Securities shall have occurred and be continuing at the
         time of such deposit or, with regard to any such event specified in
         Sections 501(7) and (8), at any time on or prior to the 91st day after
         the date of such deposit (it being understood that this condition shall
         not be deemed satisfied until after such 91st day).

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

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

                  (8) At the time of such deposit, (A) no default in the payment
         of any principal of or premium or interest on any Senior Debt of the
         Company shall have occurred and be continuing, (B) no event of default
         with respect to any Senior Debt of the Company shall have resulted in
         such Senior Debt becoming, and continuing to be, due and payable prior
         to the date on which it would otherwise have become due and payable
         (unless payment of such Senior Debt has been made or duly provided
         for), and (C) no other event of default with respect to any Senior Debt
         of the Company shall have occurred and be continuing permitting (after
         notice or lapse of time or both) the holders of such Senior Debt (or a
         trustee on behalf of such holders) to declare such


                                       61
<PAGE>   69

         Senior Debt due and payable prior to the date on which it would
         otherwise have become due and payable.

                  (9) The Company shall have delivered to the Trustee an Opinion
         of Counsel to the effect that such deposit shall not cause either the
         Trustee or the trust so created to be subject to the Investment Company
         Act of 1940.

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

SECTION 1505. Deposited Money and U.S. Government Obligations to Be Held in
Trust; Miscellaneous Provisions.

         Subject to the provisions of the last paragraph of Section 1003, all
money and U.S. Government Obligations (including the proceeds thereof) deposited
with the Trustee or other qualifying trustee (solely for purposes of this
Section and Section 1506, the Trustee and any such other trustee are referred to
collectively as the "Trustee") pursuant to Section 1504 in respect of any
Securities shall be held in trust and applied by the Trustee, in accordance with
the provisions of such Securities and this Indenture, to the payment, either
directly or through any such Paying Agent (including the Company acting as its
own Paying Agent) as the Trustee may determine, to the Holders of such
Securities, of all sums due and to become due thereon in respect of principal
and any premium and interest, but money so held in trust need not be segregated
from other funds except to the extent required by law. Money and U.S. Government
Obligations so held in trust shall not be subject to the provisions of Article
Twelve.

         The Company shall pay and indemnify the Trustee against any tax, fee or
other charge imposed on or assessed against the U.S. Government Obligations
deposited pursuant to Section 1504 or the principal and interest received in
respect thereof other than any such tax, fee or other charge which by law is for
the account of the Holders of Outstanding Securities.

         Anything in this Article to the contrary notwithstanding, the Trustee
shall deliver or pay to the Company from time to time upon Company Request any
money or U.S. Government Obligations held by it as provided in Section 1504 with
respect to any Securities which, in the opinion of a nationally recognized firm
of independent public accountants expressed in a written certification thereof
delivered to the Trustee, are in excess of the amount thereof which would then
be required to be deposited to effect the Defeasance or Covenant Defeasance, as
the case may be, with respect to such Securities.

SECTION 1506. Reinstatement.

         If the Trustee or the Paying Agent is unable to apply any money in
accordance with this Article with respect to any Securities by reason of any
order or judgment of any court or governmental authority enjoining, restraining
or otherwise prohibiting such application, then the obligations under this
Indenture and such Securities from which the Company has been discharged or
released pursuant to Section 1502 or 1503 shall be revived and reinstated as
though no deposit had occurred pursuant to this Article with respect to such
Securities, until such time as the Trustee or Paying Agent is permitted to apply
all money held in trust pursuant to Section 1505 with respect to such Securities
in accordance with this Article; provided, however, that if the Company makes
any payment of principal of or any premium or interest on any such Security
following such reinstatement of its obligations, the Company shall be subrogated
to the rights (if any) of the Holders of such Securities to receive such payment
from the money so held in trust.


                                       62
<PAGE>   70

                                 ARTICLE SIXTEEN

                                  SINKING FUNDS

SECTION 1601. Applicability of Article.

         The provisions of this Article shall be applicable to any sinking fund
for the retirement of Securities of any series except as otherwise specified as
contemplated by Section 301 for such Securities.

         The minimum amount of any sinking fund payment provided for by the
terms of any Securities is herein referred to as a "mandatory sinking fund
payment", and any payment in excess of such minimum amount provided for by the
terms of such Securities is herein referred to as an "optional sinking fund
payment". If provided for by the terms of any Securities, the cash amount of any
sinking fund payment may be subject to reduction as provided in Section 1602.
Each sinking fund payment shall be applied to the redemption of Securities as
provided for by the terms of such Securities.

SECTION 1602. Satisfaction of Sinking Fund Payments with Securities.

         The Company (1) may deliver Outstanding Securities of a series (other
than any previously called for redemption) and (2) may apply as a credit
Securities of a series which have been (x) converted pursuant to Article
Seventeen or (y) redeemed either at the election of the Company pursuant to the
terms of such Securities or through the application of permitted optional
sinking fund payments pursuant to the terms of such Securities, in each case in
satisfaction of all or any part of any sinking fund payment with respect to any
Securities of such series required to be made pursuant to the terms of such
Securities as and to the extent provided for by the terms of such Securities,
provided that the Securities to be so credited have not been previously so
credited. The Securities to be so credited shall be received and credited for
such purpose by the Trustee at the Redemption Price, as specified in the
Securities so to be redeemed, for redemption through operation of the sinking
fund and the amount of such sinking fund payment shall be reduced accordingly.

SECTION 1603. Redemption of Securities for Sinking Fund.

         Not less than 35 days prior to each sinking fund payment date for any
Securities, the Company will deliver to the Trustee an Officer's Certificate
specifying the amount of the next ensuing sinking fund payment for such
Securities pursuant to the terms of such Securities, the portion thereof, if
any, which is to be satisfied by payment of cash and the portion thereof, if
any, which is to be satisfied by delivering and crediting Securities pursuant to
Section 1602 and will also deliver to the Trustee any Securities to be so
delivered. Not less than 32 days prior to each such sinking fund payment date,
the Trustee shall select the Securities to be redeemed upon such sinking fund
payment date in the manner specified in Section 1103 and cause notice of the
redemption thereof to be given in the name of and at the expense of the Company
in the manner provided in Section 1104. Such notice having been duly given, the
redemption of such Securities shall be made upon the terms and in the manner
stated in Sections 1106 and 1107.


                                       63
<PAGE>   71

                                ARTICLE SEVENTEEN

                            CONVERSION OF SECURITIES

SECTION 1701. Applicability of Article.

         The provisions of this Article shall be applicable to the Securities of
any series which are convertible into Common Stock or, if so provided in a Board
Resolution, Officer's Certificate or executed supplemental indenture referred to
in Sections 201 and 301 by or pursuant to which the form and terms of the
Securities of such series were established, cash in lieu thereof, as and to the
extent provided by the terms of the Securities of such series.

SECTION 1702. Exercise of Conversion Privilege.

         In order to exercise the conversion privilege, the Holder of any
Security to be converted shall surrender such Security to the Conversion Agent
at any time during usual business hours at its office or agency maintained for
the purpose as provided in this Indenture, accompanied by a fully executed
written notice, in substantially the form set forth on the reverse of or
attached to the Security, that the Holder elects to convert such Security or a
stated portion thereof constituting a multiple of $1,000 in principal amount at
Maturity, and, if such Security is surrendered for conversion during the period
between the close of business on any Regular Record Date for such Security and
the opening of business on the related Interest Payment Date and has not been
called for redemption on a Redemption Date within such period, accompanied also
by payment to the Company of an amount equal to the interest payable on such
Interest Payment Date on the portion of the principal amount of the Security
being surrendered for conversion, notwithstanding such conversion. The Holder of
any Security at the close of business of a record date for such Security shall
be entitled to receive the interest payable on such Security on the
corresponding Interest Payment Date notwithstanding the conversion thereof after
such record date. The interest payment with respect to a Security called for
redemption on a date during the period from the close of business on or after
any record date for such Security to the close of business on the Business Day
following the corresponding Interest Payment Date shall be payable on the
corresponding Interest Payment Date to the Holder at the close of business of
that record date (notwithstanding the conversion of such Security before the
corresponding Interest Payment Date), and a Holder who elects to convert need
not include funds equal to the interest paid. Such notice shall also state the
name or names (and address) in which the certificate or certificates for shares
of Common Stock shall be issued (or to whom payment in cash in lieu of Common
Stock shall be made). Securities surrendered for conversion shall (if so
required by the Company or the Conversion Agent) be duly endorsed by, or be
accompanied by a written instrument or instruments of transfer in form
satisfactory to the Company and the Conversion Agent duly executed by, the
Holder or his attorney duly authorized in writing. As promptly as practicable
after the receipt of such notice and the surrender of such Security as
aforesaid, the Company shall, subject to the provisions of Section 1707, issue
and deliver at such office or agency to such Holder, or on his written order, a
certificate or certificates for the number of full shares of Common Stock
issuable on conversion of such Security in accordance with the provisions of
such Security and cash, as provided in Section 1703, in respect of any fraction
of a share of Common Stock otherwise issuable upon such conversion or, if so
provided in a Board Resolution, Officer's Certificate or executed supplemental
indenture referred to in Sections 201 and 301 by or pursuant to which the form
and terms of the Securities of such series were established, cash in lieu of
shares of Common Stock. Such conversion shall be at the Conversion Price in
effect, and shall be deemed to have been effected, immediately prior to the
close of business on the date (herein called the "Date of Conversion") on which
such notice in proper form shall have been received by the Conversion Agent and
such Security shall have been surrendered as aforesaid, and the Person or
Persons in whose name or names any certificate or certificates for shares of
Common Stock shall be issuable, if any, upon such conversion shall be deemed to
have become on the Date of Conversion the holder or holders of record of the
shares represented thereby; provided, however, that any such surrender on any
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, if any, as the record holder or
holders thereof for all purposes at the opening of business on


                                       64
<PAGE>   72

the next succeeding day on which such stock transfer books are open but such
conversion shall nevertheless be at the Conversion Price in effect at the close
of business on the date when such Security shall have been so surrendered with
the conversion notice in proper form. In the case of conversion of a portion,
but less than all, of a Security, the Company shall execute, and the Trustee
shall authenticate and deliver to the Holder thereof, at the expense of the
Company, a Security or Securities in the aggregate principal amount of the
unconverted portion of the Security surrendered. Except as otherwise expressly
provided in this Indenture, no payment or adjustment shall be made for interest
accrued on any Security (or portion thereof) converted or for dividends or
distributions on any Common Stock issued upon conversion of any Security. The
right, if any, of a Holder of any Security to cause the Company to redeem,
purchase or repay such Security shall terminate upon receipt by the Company of
any notice of conversion of such Security.

SECTION 1703. Fractional Interests.

         No fractions of shares or scrip representing fractions of shares shall
be issued upon conversion of Securities. If more than one Security shall be
surrendered for conversion at one time by the same Holder, the number of full
shares which shall be issuable upon conversion thereof shall be computed on the
basis of the aggregate principal amount of the Securities so surrendered. If any
fraction of a share of Common Stock would, except for the provisions of this
Section 1703, be issuable on the conversion of any Security or Securities, the
Company shall make payment in lieu thereof in cash equal to the value of such
fraction computed on the basis of the Last Sale Price of one share of Common
Stock on the most recent Trading Day prior to the Date of Conversion. "Last Sale
Price" on any Trading Day shall mean (i) the closing price regular way (or, if
no closing price is reported the average of the bid and asked prices) as
reported on the New York Stock Exchange Composite Tape, or (ii) if on such
Trading Day the Common Stock is not listed or admitted to trading on such
exchange, the closing price regular way (or, if no closing price is reported the
average of the bid and asked prices) on the principal national securities
exchange on which the Common Stock is listed or admitted to trading, or (iii) if
not listed or admitted to trading on any national securities exchange on such
Trading Day, then the average of the closing bid and asked prices as reported
through the National Association of Securities Dealers, Inc. on its NASDAQ
National Market or other NASDAQ market or through a similar organization if
NASDAQ is no longer reporting information, or (iv) if the Common Stock is not
listed or admitted to trading on any national securities exchange or quoted on
such National Market or other NASDAQ market on such Trading Day, then the
average of the closing bid and asked prices in the over-the-counter market as
furnished by any New York Stock Exchange member firm selected from time to time
by the Company for that purpose or (v) if not quoted by any such organization on
such Trading Day, the fair value of such Common Stock on such Trading Day, as
determined in good faith by the Board of Directors. The term "Trading Day" shall
mean each Monday, Tuesday, Wednesday, Thursday and Friday, other than any day on
which securities are not traded on any of the above mentioned exchanges or in
such markets.

SECTION 1704. Adjustment of Conversion Price.

         The conversion price or rate (herein called the "Conversion Price") for
a series of Securities shall be as set forth in a Board Resolution, Officers'
Certificate or executed supplemental indenture referred to in Sections 201 and
301 by or pursuant to which the form and terms of the Securities of such series
were established, and, except as otherwise provided therein, shall be subject to
adjustment from time to time as follows:

         (a) In case the Company shall (1) make or pay a dividend (or other
distribution) in shares of Common Stock on any class of Capital Stock of the
Company, (2) subdivide its outstanding shares of Common Stock into a greater
number of shares, (3) combine its outstanding shares of Common Stock


                                       65
<PAGE>   73

into a smaller number of shares or (4) issue by reclassification of its Common
Stock any shares of Capital Stock of the Company, the Conversion Price in effect
immediately prior to such action shall be adjusted so that the Holder of any
Security thereafter surrendered for conversion shall be entitled to receive the
number of shares of Common Stock or other Capital Stock of the Company which he
would have owned immediately following such action had such Security been
converted immediately prior thereto. An adjustment made pursuant to this
subsection (a) shall become effective immediately, except as provided in
subsection (h) below, after the record date in the case of a dividend or
distribution and shall become effective immediately after the effective date in
the case of a subdivision, combination or reclassification. If as a result of an
adjustment made pursuant to this subsection (a), the Holder of any Security
thereafter surrendered for conversion shall become entitled to receive shares of
two or more classes of Capital Stock (including shares of Common Stock) of the
Company, the Board of Directors (whose determination shall, if made in good
faith, be conclusive and shall be described in a statement filed with the
Trustee) shall determine the allocation of the adjusted Conversion Price between
or among shares of such classes of Capital Stock.

         (b) In case the Company shall issue rights, options or warrants to all
holders of 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
(as determined pursuant to subsection (f) below) of the Common Stock on the
record date mentioned below, the Conversion Price shall be adjusted to a price,
computed to the nearest cent, so that the same shall equal the price determined
by multiplying:

                  (1) the Conversion Price in effect immediately prior to the
         date of issuance of such rights, options or warrants by a fraction, of
         which

                  (2) the numerator shall be (A) the aggregate number of shares
         of Common Stock, Limited Vote Common Stock and As-Converted Series A
         Preferred Shares outstanding on the date of issuance of such rights,
         options or warrants, immediately prior to such issuance, plus (B) the
         number of shares which the aggregate offering price of the total number
         of shares so offered for subscription or purchase would purchase at
         such current market price (determined by multiplying such total number
         of shares by the exercise price of such rights, options or warrants and
         dividing the product so obtained by such current market price), and of
         which

                  (3) the denominator shall be (A) the aggregate number of
         shares of Common Stock, Limited Vote Common Stock and As-Converted
         Series A Preferred Shares outstanding on the date of issuance of such
         rights, options or warrants, immediately prior to such issuance, plus
         (B) the number of additional shares of Common Stock which are so
         offered for subscription or purchase.

Such adjustment shall become effective immediately, except as provided in
subsection (h) below, after the record date for the determination of holders
entitled to receive such rights, options or warrants; provided, however, that if
any such rights, options or warrants issued by the Company as described in this
subsection (b) are only exercisable upon the occurrence of certain triggering
events relating to control and provided for in shareholders' rights plans, then
the Conversion Price shall not be adjusted as provided in this subsection (b)
until such triggering events shall occur; and provided further that if any such
rights, options or warrants expire unexercised, the Conversion Price shall be
readjusted to take into account only the number of such rights, options or
warrants actually exercised.

         (c) In case the Company or any of its Subsidiaries shall distribute to
all holders of Common Stock evidences of indebtedness, shares of Capital Stock
other than Common Stock, cash or other assets (including securities, but other
than (x) regular dividends or distributions paid exclusively in cash or (y)


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<PAGE>   74

any dividend or distribution for which an adjustment is required to be made in
accordance with subsection (a) or (b) above), subsection (a) or (b) above), then
in each such case the Conversion Price shall be adjusted so that the same shall
equal the price determined by multiplying the Conversion Price in effect
immediately prior to the date of such distribution by a fraction of which the
numerator shall be the current market price per share (determined as provided in
subsection (f) below) of the Common Stock on the record date mentioned below
less the then fair market value (as determined by the Board of Directors, whose
determination shall, if made in good faith, be conclusive evidence of such fair
market value) of the portion of the assets so distributed applicable to one
share of Common Stock, and of which the denominator shall be such current market
price per share of the Common Stock. Such adjustment shall become effective
immediately, except as provided in subsection (h) below, after the record date
for the determination of stockholders entitled to receive such distribution.
Notwithstanding the foregoing, in the event that the fair market value of the
assets, evidences of indebtedness or other securities so distributed applicable
to one share of Common Stock equals or exceeds such current market price per
share of Common Stock, or such current market price exceeds such fair market
value by less than $0.10 per share, the Conversion Price shall not be adjusted
pursuant to this subsection (c) and, to the extent applicable, the provisions of
subsection (k) shall apply to such distribution.

         (d) In case the Company or any Subsidiary of the Company shall make any
distribution consisting exclusively of cash (excluding any cash portion of
distributions for which an adjustment is required to be made in accordance with
(c) above, or cash distributed upon a merger or consolidation to which Section
1705 applies) to all holders of Common Stock in an aggregate amount that,
combined together with (i) all other such all-cash distributions made within the
then preceding 12 months in respect of which no adjustment has been made and
(ii) any cash and the fair market value of other consideration paid or payable
in respect of any tender offer by the Company or any of its Subsidiaries for
Common Stock concluded within the preceding 12 months in respect of which no
adjustment has been made, exceeds 15% of the Company's market capitalization
(defined as being the product of the then current market price of the Common
Stock (determined as provided in subsection (f) below) times the aggregate
number of shares of Common Stock, Limited Vote Common Stock and As-Converted
Series A Preferred Shares then outstanding) on the record date of such
distribution, then in each such case the Conversion Price shall be adjusted so
that the same shall equal the price determined by multiplying the Conversion
Price in effect immediately prior to the date of such distribution by a fraction
of which the numerator shall be the then current market price per share of the
Common Stock on such record date less the amount of the cash so distributed
applicable to one share of Common Stock, and of which the denominator shall be
such current market price per share of the Common Stock. Such adjustment shall
become effective immediately, except as provided in subsection (h) below, after
the record date for the determination of stockholders entitled to receive such
distribution. Notwithstanding the foregoing, in the event that the cash so
distributed applicable to one share of Common Stock equals or exceeds such
current market price per share of Common Stock, or such current market price
exceeds such amount of cash by less than $0.10 per share, the Conversion Price
shall not be adjusted pursuant to this subsection (d), and, to the extent
applicable, the provisions of subsection (k) shall apply to such distribution.

         (e) In case there shall be completed a tender or exchange offer made by
the Company or any Subsidiary of the Company for all or any portion of the
Common Stock (any such tender or exchange offer being referred to as an "Offer")
that involves an aggregate consideration having a fair market value as of the
expiration of such Offer (the "Expiration Time") that, together with (i) any
cash and the fair market value of any other consideration payable in respect of
any other Offer, as of the expiration of such other Offer, expiring within the
12 months preceding the expiration of such Offer and in respect of which no
Conversion Price adjustment pursuant to this subsection (e) has been made and
(ii) the aggregate amount of any all-cash distributions referred to in
subsection (d) of this Section 1704 to all holders of Common Stock within the 12
months preceding the expiration of such Offer for which no Conversion


                                       67
<PAGE>   75

Price adjustment pursuant to such subsection (d) has been made, exceeds 15% of
the product of the then current market price per share (determined as provided
in subsection (f) below) of the Common Stock at the Expiration Time times the
aggregate number of shares of Common Stock, Limited Vote Common Stock and
As-Converted Series A Preferred Shares outstanding (including any tendered
shares) at the Expiration Time, the Conversion Price shall be reduced by
multiplying such Conversion Price in effect immediately prior to the Expiration
Time by a fraction of which the numerator shall be the product of the then
current market price per share (determined as provided in subsection (f) below)
of the Common Stock at the Expiration Time times the aggregate number of shares
of Common Stock, Limited Vote Common Stock and As-Converted Series A Preferred
Shares outstanding (including any tendered shares) at the Expiration Time and
the denominator shall be the sum of (i) the fair market value of the aggregate
consideration payable to stockholders based on the acceptance (up to any maximum
specified in the terms of the Offer) of all shares validly tendered and not
withdrawn as of the Expiration Time (the shares deemed so accepted being
referred to as the "Purchased Shares") and (ii) the product of (x) such current
market price per share at the Expiration Time times (y) such number of
outstanding shares at the Expiration Time less the number of Purchased Shares,
such reduction to become effective immediately prior to the opening of business
on the day following the Expiration Time.

         For purposes of this subsection (e), the fair market value of any
consideration with respect to an Offer shall be determined by the Board of
Directors of the Company (whose determination shall, if made in good faith, be
conclusive evidence of such fair market value) and described in a Board
Resolution.

         (f) For the purpose of any computation under subsections (b), (c), (d)
and (e) above, the current market price per share of Common Stock on any date
shall be deemed to be the average of the Last Sale Prices of a share of Common
Stock for the five consecutive Trading Days selected by the Company commencing
not more than 20 Trading Days before, and ending not later than, the earlier of
the date in question and the date before the "ex date," with respect to the
issuance, distribution or Offer requiring such computation. For purposes of this
paragraph, the term "ex date," when used with respect to any issuance,
distribution or payments with respect to an Offer, means the first date on which
the Common Stock trades regular way on the New York Stock Exchange (or if not
listed or admitted to trading thereon, then on the principal national securities
exchange on which the Common Stock is listed or admitted to trading) without the
right to receive such issuance, distribution or Offer.

         (g) In addition the foregoing adjustments in subsections (a), (b), (c),
(d) and (e) above, the Company will be permitted to make such reductions in the
Conversion Price as it considers to be advisable in order that any event treated
for Federal income tax purposes as a dividend of stock or stock rights will not
be taxable to the holders of the shares of Common Stock.

         In the event the Company elects to make such a reduction in the
Conversion Price, the Company shall comply with the requirements of Rule 14e-1
of the Exchange Act and any other Federal and state laws and regulations
thereunder if and to the extent that such laws and regulations are applicable in
connection with the reduction of the Conversion Price; provided, however, that
any provisions of this Indenture which conflict with such laws shall be deemed
to be superseded by the provisions of such laws.

         (h) In any case in which this Section 1704 shall require that an
adjustment (including by reason of the second sentence of subsection (a) or (c)
above) be made immediately following a record date, the Company may elect to
defer the effectiveness of such adjustment (but in no event until a date later
than the effective time of the event giving rise to such adjustment), in which
case the Company shall, with respect to any Security converted after such record
date and before such adjustment shall have become effective, (i) defer paying
any cash payment pursuant to Section 1703 or issuing to the Holder of such
Security the number of shares of Common Stock and other Capital Stock of the
Company (or other


                                       68
<PAGE>   76

assets or securities) issuable upon such conversion in excess of the number of
shares of Common Stock and other Capital Stock of the Company issuable thereupon
only on the basis of the Conversion Price prior to adjustment and (ii), not
later than five Business Days after such adjustment shall have become effective,
pay to such Holder the appropriate cash payment pursuant to Section 1703 and
issue to such Holder the additional shares of Common Stock and other Capital
Stock of the Company (or other assets or securities) issuable on such
conversion.

         (i) No adjustment in the Conversion Price shall be required unless such
adjustment would require an increase or decrease of at least 1% of the
Conversion Price; provided, however, that any adjustments which by reason of
this subsection (i) are not required to be made shall be carried forward and
taken into account in any subsequent adjustment. All calculations under this
Article Seventeen shall be made to the nearest cent or to the nearest
one-hundredth of a share, as the case may be.

         (j) Whenever the Conversion Price is adjusted as herein provided, the
Company shall promptly (i) file with the Trustee and each Conversion Agent an
Officer's Certificate setting forth the Conversion Price after such adjustment
and setting forth a brief statement of the facts requiring such adjustment,
which certificate shall be conclusive evidence of the correctness of such
adjustment, and (ii) give or cause to be given a notice of such adjustment to
each Holder of Securities in the manner provided in Section 106.

         (k) In the event that the Company distributes rights (including rights
to distributions referred to by paragraphs (c) and (d) of this Section 1704 to
the extent this paragraph (k) applies thereto), options or warrants (other than
those referred to in subsection (b) above) pro rata to holders of Common Stock,
so long as any such rights, options or warrants have not expired or been
redeemed by the Company, the Company shall make proper provision so that the
Holder of any Security surrendered for conversion will be entitled to receive
upon such conversion, in addition to the shares of Common Stock issuable upon
such conversion (the "Conversion Shares"), a number of rights or warrants to be
determined as follows: (i) if such conversion occurs on or prior to the date for
the distribution to the holders of rights, options or warrants of separate
certificates evidencing such rights, options or warrants (the "Distribution
Date"), the same number of rights, options or warrants to which a holder of a
number of shares of Common Stock equal to the number of Conversion Shares is
entitled at the time of such conversion in accordance with the terms and
provisions of and applicable to the rights, options or warrants, and (ii) if
such conversion occurs after such Distribution Date, the same number of rights,
options or warrants to which a holder of the number of shares of Common Stock
into which the principal amount of such Security so converted was convertible
immediately prior to such Distribution Date would have been entitled on such
Distribution Date in accordance with the terms and provisions of and applicable
to the rights, options or warrants.

SECTION 1705. Continuation of Conversion Privilege in Case of Merger,
Consolidation or Sale of Assets.

         If any of the following shall occur, namely: (a) any reclassification
or change of outstanding Conversion Shares (other than a change in par value, or
from par value to no par value, or from no par value to par value, or as a
result of a subdivision or combination), (b) any consolidation or merger of the
Company with or into any other Person, or the merger of any other Person with or
into the Company (other than a merger which does not result in any
reclassification, change, conversion, exchange or cancellation of outstanding
shares of Common Stock) or (c) any transfer, conveyance, sale, lease or other
disposition of all or substantially all of the assets of the Company, then the
Company, or such successor or purchasing Person, as the case may be, shall, as a
condition precedent to such reclassification, change, consolidation, merger or
disposition, execute and deliver to the Trustee a supplemental indenture


                                       69
<PAGE>   77


providing that the Holder of each Security then outstanding shall have the right
to convert such Security only into the kind and amount of shares of stock and
other securities and property (including cash) receivable upon such
reclassification, change, consolidation, merger or disposition by a holder of
the number of shares of Common Stock issuable upon conversion of such Security
immediately prior to such reclassification, change, consolidation, merger or
disposition assuming such holder of Common Stock of the Company failed to
exercise his rights of an election, if any, as to the kind or amount of
securities, cash and other property receivable upon such reclassification,
change, consolidation, merger or disposition (provided that if the kind or
amount of securities, cash and other property receivable upon such
reclassification, change, consolidation, merger or disposition is not the same
for each share of Common Stock of the Company held immediately prior to such
reclassification, change, consolidation, merger or disposition in respect of
which such rights of election shall not have been exercised ("non-electing
share"), then for the purpose of this Section 1705 the kind and amount of
securities, cash and other property receivable upon such reclassification,
change, consolidation, merger or disposition by 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 shall be as nearly equivalent as may be practicable to the adjustments
provided for in this Article Seventeen. If, in the case of any such
consolidation, merger or disposition, the stock or other securities and property
(including cash) receivable thereupon or in connection therewith by a holder of
shares of Common Stock includes shares of stock or other securities and property
(including cash) of a Person other than the successor or purchasing Person, as
the case may be, in such consolidation, merger or disposition, then such
supplemental indenture shall also be executed by such other Person and shall
contain such additional provisions to protect the interests of the Holders of
the Securities as the Board of Directors shall reasonably consider necessary by
reason of the foregoing. The provisions of this Section 1705 shall similarly
apply to successive consolidations, mergers or dispositions.

         Notice of the execution of each such supplemental indenture shall be
given to each Holder of Securities in the manner provided in Section 106.

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 (including cash) receivable by Holders of
Securities upon the conversion of their Securities after any such
reclassification, change, consolidation, merger or disposition or to any
adjustment to be made with respect thereto, but, subject to the provisions of
Sections 601 and 603, may accept as conclusive evidence of the correctness of
any such provision, and shall be protected in relying upon, the Officer's
Certificate (which the Company shall be obligated to file with the Trustee prior
the execution of any such supplemental indenture) with respect thereto.

SECTION 1706. Notice of Certain Events.

         If:

         (a) the Company shall declare a dividend (or any other distribution)
payable to the holders of Common Stock otherwise than in cash; or

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

         (c) the Company shall authorize any reclassification or change of the
Common Stock (other than a subdivision or combination of its outstanding shares
of Common Stock), or any consolidation or merger to which the Company is a party
and for which approval of any stockholders of the Company is


                                       70
<PAGE>   78

required under the laws of the state of incorporation of the Company, or the
transfer, conveyance, sale, lease or other disposition of all or substantially
all of the assets of the Company; or

         (d) there shall be authorized or ordered any voluntary or involuntary
dissolution, liquidation or winding-up of the Company; or

         (e) the Company or any of its Subsidiaries shall complete an Offer;

then, the Company shall cause to be filed at the office or agency maintained for
the purpose of conversion of the Securities as provided in Section 1002, and
shall cause to be given to each Holder of Securities, in the manner provided in
Section 106, at least 20 days before the date hereinafter specified (or the
earlier of the dates hereinafter specified, in the event that more than one date
is specified), a notice stating the date on which (1) a record is expected to be
taken for the purpose of such dividend, distribution, rights, warrants, options
or Offer, or if a record is not to be taken, the date as of which the holders of
Common Stock of record to be entitled to such dividend, distribution, rights,
warrants or options or to participate in such Offer are to be determined, or (2)
such reclassification, change, consolidation, merger, disposition, dissolution,
liquidation or winding-up is expected to become effective and the date, if any
is to be fixed, 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
or other property deliverable upon such reclassification, change, consolidation,
merger, disposition, dissolution, liquidation or winding-up.

SECTION 1707. Taxes on Conversion.

         The Company will pay any and all documentary, stamp or similar taxes
payable to the United States of America or any political subdivision or taxing
authority thereof or therein in respect of the issue or delivery of shares of
Common Stock on conversion of Securities pursuant thereto; provided, however,
that the Company shall not be required to pay any tax which may be payable in
respect of any transfer involved in the issue or delivery of shares of Common
Stock in a name other than that of the Holder of the Securities to be converted
(or payment of cash in lieu thereof to a Person other than such Holder) and no
such issue or delivery (or payment) shall be made unless and until the Person
requesting such issue or delivery (or payment) has paid to the Company the
amount of any such tax or has established, to the satisfaction of the Company,
that such tax has been paid. The Company extends no protection with respect to
any other taxes imposed in connection with conversion of Securities.

SECTION 1708. Company to Provide Stock.

         The Company shall reserve, free from preemptive rights, out of its
authorized but unissued shares, sufficient shares to provide for the conversion
of convertible Securities from time to time as such Securities are presented for
conversion, provided, however, that nothing contained herein shall be construed
to preclude the Company from satisfying its obligations in respect of the
conversion of Securities by delivery of repurchased shares of Common Stock which
are held in the treasury of the Company.

         If any shares of Common Stock to be reserved for the purpose of
conversion of Securities hereunder require registration with or approval of any
governmental authority under any Federal or State law before such shares may be
validly issued or delivered upon conversion, then the Company covenants that it
will in good faith and as expeditiously as possible endeavor to secure such
registration or approval, as the case may be; provided, however, that nothing in
this Section 1708 shall be deemed to affect in any way the obligations of the
Company to convert Securities into Common Stock as provided in this Article
Seventeen.


                                       71
<PAGE>   79

         Before taking any action which would cause an adjustment reducing the
Conversion Price below the then par value, if any, of the Common Stock, the
Company will take all corporate action which may, in the opinion of counsel, be
necessary in order that the Company may validly and legally issue fully paid and
non-assessable shares of Common Stock at such adjusted Conversion Price.

         The Company covenants that all shares of Common Stock which may be
issued upon conversion of Securities will upon issue be fully paid and
non-assessable by the Company and free of preemptive rights.

SECTION 1709. Disclaimer of Responsibility for Certain Matters.

         Neither the Trustee, any Conversion Agent nor any agent of either shall
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 Price, or with respect to the Officer's Certificate referred to in
Section 1704(j), or with respect to the nature or extent of any such adjustment
when made, or with respect to the method employed, or herein or in any
supplemental indenture provided to be employed, in making the same. Neither the
Trustee, any Conversion Agent nor any agent of either shall be accountable with
respect to the validity or value (or the kind or amount) of any shares of Common
Stock, or of any securities or property (including cash), which may at any time
be issued or delivered upon the conversion of any Security, and neither the
Trustee, any Conversion Agent nor any agent of either makes any representation
with respect thereto. Neither the Trustee, any Conversion Agent nor any agent of
either shall be responsible for any failure of the Company to issue, register
the transfer of or deliver any shares of Common Stock or stock certificates or
other securities or property (including cash) upon the surrender of any Security
for the purpose of conversion or, subject to Sections 601 and 603, to comply
with any of the covenants of the Company contained in this Article Seventeen.

SECTION 1710. Return of Funds Deposited for Redemption of Converted Securities.

         Any funds which at any time shall have been deposited by the Company or
on its behalf with the Trustee or any Paying Agent for the purpose of paying the
principal of and interest, if any, on any of the Securities and which shall not
be required for such purposes because of the conversion of such Securities, as
provided in this Indenture, shall forthwith after such conversion be repaid to
the Company by the Trustee or such Paying Agent.



                                       72
<PAGE>   80





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

                                   Quanta Services, Inc.


                                   By:    /s/ Brad Eastman
                                          ------------------------
                                   Name:  Brad Eastman
                                   Its:   Vice President

                                   Chase Bank of Texas, National Association,
                                   as Trustee


                                   By:    /s/ John G. Jones
                                          ------------------------
                                   Name:  John G. Jones
                                   Its:   Vice President





                                       73