<PAGE>

                                                                     EXHIBIT 4.3

                          CONCORD COMMUNICATIONS, INC.,

                                    AS ISSUER

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

                            WILMINGTON TRUST COMPANY,
                                   AS TRUSTEE

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

                 UP TO $86,250,000 AGGREGATE PRINCIPAL AMOUNT OF
                     3.0% CONVERTIBLE SENIOR NOTES DUE 2023

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

                                    INDENTURE
                          DATED AS OF DECEMBER 8, 2003

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


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                                TABLE OF CONTENTS

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ARTICLE I            DEFINITIONS AND INCORPORATION BY REFERENCE.....................................      1

         Section 1.1.       Definitions.............................................................      1

         Section 1.2.       Incorporation by Reference of Trust Indenture Act.......................      9

         Section 1.3.       Rules of Construction...................................................     10

         Section 1.4.       Acts of Holders.........................................................     10

ARTICLE II           THE SECURITIES.................................................................     11

         Section 2.1.       Form and Dating.........................................................     11

         Section 2.2.       Execution and Authentication............................................     12

         Section 2.3.       Registrar, Paying Agent and Conversion Agent............................     13

         Section 2.4.       Paying Agent to Hold Cash and Securities in Trust.......................     14

         Section 2.5.       Holder Lists............................................................     14

         Section 2.6.       Transfer and Exchange...................................................     15

         Section 2.7.       Replacement Securities..................................................     16

         Section 2.8.       Outstanding Securities; Determinations of Holders' Action...............     16

         Section 2.9.       Temporary Securities....................................................     17

         Section 2.10.      Cancellation............................................................     18

         Section 2.11.      Persons Deemed Owners...................................................     18

         Section 2.12.      Additional Transfer and Exchange Requirements...........................     18

         Section 2.13.      CUSIP Numbers...........................................................     24

         Section 2.14.      Ranking.................................................................     24
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ARTICLE III          REDEMPTION.....................................................................     25

         Section 3.1.       The Company's Right to Redeem; Notice to Trustee........................     25

         Section 3.2.       Selection of Securities to Be Redeemed..................................     25

         Section 3.3.       Notice of Redemption....................................................     26

         Section 3.4.       Effect of Notice of Redemption..........................................     27

         Section 3.5.       Deposit of Redemption Price.............................................     27

         Section 3.6.       Securities Redeemed in Part.............................................     27

         Section 3.7.       Repayment to the Company................................................     27

         Section 3.8.       No Sinking Fund.........................................................     27

ARTICLE IV           PURCHASE AT THE OPTION OF HOLDERS ON SPECIFIC DATES............................     28

         Section 4.1.       Optional Put............................................................     28

         Section 4.2.       Effect of Purchase Notice; Withdrawal of Purchase Notice................     30

         Section 4.3.       Deposit of Purchase Price...............................................     31

         Section 4.4.       Securities Purchased in Part............................................     31

         Section 4.5.       Covenant to Comply With Securities Laws Upon Purchase of Securities.....     32

         Section 4.6.       Repayment to the Company................................................     32

         Section 4.7.       No Purchase Upon Event of Default.......................................     32

ARTICLE V            PURCHASE AT THE OPTION OF HOLDERS UPON A DESIGNATED EVENT......................     32

         Section 5.1.       Designated Event Put....................................................     32

         Section 5.2.       Effect of Designated Event Purchase Notice..............................     35
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         Section 5.3.       Deposit of Designated Event Purchase Price..............................     36

         Section 5.4.       Securities Purchased in Part............................................     36

         Section 5.5.       Covenant to Comply With Securities Laws Upon Purchase of Securities.....     37

         Section 5.6.       Repayment to the Company................................................     37

ARTICLE VI           COVENANTS......................................................................     37

         Section 6.1.       Payment of Securities...................................................     37

         Section 6.2.       SEC and Other Reports to the Trustee....................................     38

         Section 6.3.       Compliance Certificate..................................................     39

         Section 6.4.       Further Instruments and Acts............................................     39

         Section 6.5.       Maintenance of Office or Agency of the Trustee, Registrar, Paying
                            Agent and Conversion Agent..............................................     39

         Section 6.6.       Delivery of Information Required Under Rule 144A........................     40

         Section 6.7.       Waiver of Stay, Extension or Usury Laws.................................     40

         Section 6.8.       Statement by Officers as to Default.....................................     40

ARTICLE VII          SUCCESSOR CORPORATION..........................................................     41

         Section 7.1.       When Company May Merge or Transfer Assets...............................     41

ARTICLE VIII         DEFAULTS AND REMEDIES..........................................................     42

         Section 8.1.       Events of Default.......................................................     42

         Section 8.2.       Acceleration............................................................     44

         Section 8.3.       Other Remedies..........................................................     44

         Section 8.4.       Waiver of Past Defaults.................................................     44
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         Section 8.5.       Control by Majority.....................................................     45

         Section 8.6.       Limitation on Suits.....................................................     45

         Section 8.7.       Rights of Holders to Receive Payment or to Convert......................     46

         Section 8.8.       Collection Suit by Trustee..............................................     46

         Section 8.9.       Trustee May File Proofs of Claim........................................     46

         Section 8.10.      Priorities..............................................................     47

         Section 8.11.      Undertaking for Costs...................................................     47

ARTICLE IX           TRUSTEE........................................................................     47

         Section 9.1.       Duties of Trustee.......................................................     47

         Section 9.2.       Rights of Trustee.......................................................     49

         Section 9.3.       Individual Rights of Trustee............................................     50

         Section 9.4.       Trustee's Disclaimer....................................................     50

         Section 9.5.       Notice of Defaults......................................................     50

         Section 9.6.       Reports by Trustee to Holders...........................................     51

         Section 9.7.       Compensation and Indemnity..............................................     51

         Section 9.8.       Replacement of Trustee..................................................     52

         Section 9.9.       Successor Trustee by Merger.............................................     53

         Section 9.10.      Eligibility; Disqualification...........................................     53

         Section 9.11.      Preferential Collection of Claims Against Company.......................     53

ARTICLE X            DISCHARGE OF INDENTURE.........................................................     53

         Section 10.1.      Discharge of Liability on Securities....................................     53
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         Section 10.2.      Repayment to the Company................................................     54

ARTICLE XI           AMENDMENTS.....................................................................     54

         Section 11.1.      Without Consent of Holders..............................................     54

         Section 11.2.      With Consent of Holders.................................................     55

         Section 11.3.      Compliance with Trust Indenture Act.....................................     56

         Section 11.4.      Revocation and Effect of Consents, Waivers and Actions..................     56

         Section 11.5.      Notation on or Exchange of Securities...................................     57

         Section 11.6.      Trustee to Sign Supplemental Indentures.................................     57

         Section 11.7.      Effect of Supplemental Indentures.......................................     57

ARTICLE XII          CONVERSION.....................................................................     57

         Section 12.1.      Conversion Right........................................................     57

         Section 12.2.      Conversion Procedures; Conversion Rate; Fractional Shares...............     59

         Section 12.3.      Adjustment of Conversion Rate...........................................     61

         Section 12.4.      Consolidation or Merger of the Company..................................     69

         Section 12.5.      Notice of Adjustment....................................................     71

         Section 12.6.      Notice in Certain Events................................................     71

         Section 12.7.      Company To Reserve Stock:  Registration; Listing........................     72

         Section 12.8.      Taxes on Conversion.....................................................     72

         Section 12.9.      Conversion After Regular Record Date....................................     73

         Section 12.10.     Company Determination Final.............................................     73

         Section 12.11.     Responsibility of Trustee for Conversion Provisions.....................     73
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         Section 12.12.     Unconditional Right of Holders to Convert...............................     73

         Section 12.13.     Option to Satisfy Conversion Obligation with Cash, Common Stock or
                            Combination Thereof.....................................................     74

ARTICLE XIII         MISCELLANEOUS..................................................................     76

         Section 13.1.      Trust Indenture Act Controls............................................     76

         Section 13.2.      Notices.................................................................     76

         Section 13.3.      Communication by Holders with Other Holders.............................     77

         Section 13.4.      Certificate and Opinion as to Conditions Precedent......................     77

         Section 13.5.      Statements Required in Certificate or Opinion...........................     77

         Section 13.6.      Separability Clause.....................................................     78

         Section 13.7.      Rules by Trustee, Paying Agent, Conversion Agent, Registrar.............     78

         Section 13.8.      Legal Holidays..........................................................     78

         Section 13.9.      Governing Law; Submission to Jurisdiction; Service of Process...........     78

         Section 13.10.     No Recourse Against Others..............................................     79

         Section 13.11.     Successors..............................................................     79

         Section 13.12.     Multiple Originals......................................................     79
</TABLE>

EXHIBIT A      Form of Security
EXHIBIT B    Form of Certificate to be Delivered by Transferee in Connection
               with Transfers to Institutional Accredited Investors
EXHIBIT C    Form of Restrictive Legend for Common Stock Issues Upon Conversion

                                       vi

<PAGE>

INDENTURE, dated as of December 8, 2003, between CONCORD COMMUNICATIONS, INC., a
Massachusetts corporation (the "COMPANY"), and Wilmington Trust Company, a
Delaware banking corporation, as Trustee (the "TRUSTEE").

Each party agrees as follows for the benefit of the other party and for the
equal and ratable benefit of the Holders of the Company's 3.0% Convertible
Senior Notes due 2023:

                                   ARTICLE I

                   DEFINITIONS AND INCORPORATION BY REFERENCE

Section 1.1. Definitions.

"ADDITIONAL INTEREST" has the meaning set forth in the Registration Rights
Agreement. All references herein or in the Securities to interest accrued or
payable as of any date shall include any Additional Interest accrued or payable
as of such date as provided in the Registration Rights Agreement.

"ADDITIONAL SHARES" has the meaning set forth in the Registration Rights
Agreement.

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

"AGENT MEMBERS" has the meaning set forth in Section 2.1(b).

"APPLICABLE PROCEDURES" means, with respect to any transfer or transaction
involving a Global Security or beneficial interest therein, the rules and
procedures of the Depositary for such Security, in each case to the extent
applicable to such transaction and as in effect from time to time.

"APPLICABLE STOCK" means (a) the Common Stock and (b) in the event of a merger,
consolidation or other similar transaction involving the Company that is
otherwise permitted hereunder in which the Company is not the surviving
corporation, the common stock of such surviving corporation or its direct or
indirect, as applicable, parent corporation.

"BANKRUPTCY LAW" means Title 11, United States Code, or any similar United
States federal or state law for the relief of debtors.

"BOARD OF DIRECTORS" means either the board of directors of the Company or any
duly authorized committee of such board.

"BOARD RESOLUTION" means a resolution of the Board of Directors.

"BUSINESS DAY" means each day of the year other than a Saturday or a Sunday or
other day on which banking institutions in the City of New York are required or
authorized by law, regulation or executive order to close.

"CASH" means such coin or currency of the United States as at any time of
payment is legal tender for the payment of public and private debts.

"CASH SETTLEMENT AVERAGING PERIOD" has the meaning set forth in Section
12.13(a).

"CERTIFICATED SECURITIES" means Securities that are in substantially the form
attached hereto as Exhibit A and that do not include the information called for
by footnotes 1 and 2 thereof.

"CLOSING SALE PRICE" of a share of Applicable Stock on any date means the
closing per share sale price (or, if no closing sale price is reported, the
average of the bid and ask prices or, if more than one in either case, the
average of the average bid and the average ask prices) on such date as reported
by the Nasdaq National Market system or, if the shares of Applicable Stock are
not quoted on the Nasdaq National Market system, as reported on a national
securities exchange. If the Applicable Stock is not listed for trading on a
national securities exchange and not quoted by the Nasdaq National Market on the
relevant date, the "Closing Sale Price" shall be the last quoted bid for the
Applicable Stock in the over-the-counter market on the relevant date as reported
by the National Quotation Bureau or similar organization. If the Applicable
Stock is not so quoted, the "Closing Sale Price" shall be the average of the
midpoint of the last bid and ask prices for the Applicable Stock on the relevant
date from each of at least three nationally recognized independent investment
banking firms selected by us for this purpose.

"CODE" means the Internal Revenue Code of 1986, as amended.

"COMMON STOCK" means the authorized common stock, $0.01 par value per share, of
the Company or

<PAGE>

any other shares of Equity Interest of the Company into which such Common Stock
shall be reclassified or changed.

"COMPANY" means the party named as the "Company" in the first paragraph of this
Indenture until a successor replaces it pursuant to the applicable provisions of
this Indenture and, thereafter, means such successor. The foregoing sentence
shall likewise apply to any subsequent successor or successors to such
successors.

"COMPANY REQUEST" or "COMPANY ORDER" means a written request or order signed in
the name of the Company by any two Officers, at least one of whom is the Chief
Executive Officer or the Chief Financial Officer.

"CONVERSION AGENT" has the meaning set forth in Section 2.3.

"CONVERSION NOTICE" has the meaning set forth in Section 12.2(b).

"CONVERSION PERIOD" means the period from and including the 30th Trading Day in
a fiscal quarter of the Company to, but not including, the 30th Trading Day (or
if that day is not a Trading Day, then the next Trading Day) in the immediately
following fiscal quarter of the Company.

"CONVERSION PRICE" means, at any time, $1,000 divided by the Conversion Rate in
effect at such time, rounded to two decimal places (rounded up if the third
decimal place thereof is 5 or more and otherwise rounded down).

"CONVERSION RATE" means the number of shares of Common Stock issuable upon
conversion of each $1,000 of Principal Amount of Securities, which is initially
37.2148 shares, subject to adjustments as set forth in this Indenture.

"CONVERSION SETTLEMENT STOCK PRICE" means the arithmetic average of the Closing
Prices of Common Stock during the Cash Settlement Averaging Period.

"CORPORATE TRUST OFFICE" means the principal office of the Trustee at which at
any time its corporate trust business shall be administered, which office at the
date hereof is located at 1100 North Market Street, Rodney Square North,
Wilmington, DE 19890-1615, or such other address as the Trustee may designate
from time to time by notice to the Holders and the Company, or the principal
corporate trust office of any successor Trustee (or such other address as a
successor Trustee may designate from time to time by notice to the Holders and
the Company).

"CURRENT MARKET PRICE" has the meaning set forth in Section 12.3(g).

"CUSTODIAN" means any receiver, trustee, assignee, liquidator, custodian or
similar official under any Bankruptcy Law.

"DEFAULT" means, when used with respect to the Securities, any event which is,
or after notice or passage of time or both would be, an Event of Default.

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

"DESIGNATED EVENT" means the occurrence of any of the following events: (i) any
"person" or "group" (as such terms are used in Sections 13(d) and 14(d) of the
Exchange Act), is or becomes the "beneficial owner" (as defined in Rules 13d-3
and 13d-5 under the Exchange Act, except that a Person shall be deemed to have
beneficial ownership of all shares that such Person has the right to acquire,
whether such right is exercisable immediately or only after the passage of
time), directly or indirectly, of more than 50% of the total outstanding Voting
Stock of the Company; (ii) during any period of two consecutive years,
individuals who at the beginning of such period constituted the Board of
Directors (together with any new directors whose election to such Board of
Directors or whose nomination for election by the stockholders of the Company,
was approved by a vote of at least 66-2/3% of the directors then still in office
who were either directors at the beginning of such period or whose election or
nomination for election was previously so approved) cease for any reason to
constitute a majority of such Board of Directors then in office; (iii) the
Company consolidates with or merges with or into any Person or conveys,
transfers, sells or otherwise disposes of or leases all or substantially all of
its assets to any Person, or any corporation consolidates with or merges into or
with the Company, in any such event pursuant to a transaction in which the
outstanding Voting Stock of the Company is changed into or exchanged for cash,
securities or other property, other than any such transaction where the
outstanding Voting Stock of the Company is not changed or exchanged at all
(except to the extent necessary to reflect a change in the jurisdiction of
incorporation of the Company) or where (A) the outstanding Voting Stock of the
Company is changed into or exchanged for cash, securities and other property
(other than Equity Interest of the surviving corporation) and (B) the
stockholders of the Company immediately before such transaction constituting a

                                       2
<PAGE>

change of control own, directly or indirectly, immediately following such
transaction, more than 50% of the total outstanding Voting Stock of the
surviving corporation; (iv) the Company or any Designated Subsidiary is
liquidated or dissolved or adopts a plan of liquidation or dissolution other
than in a transaction which complies with the provisions described under Article
VII; or (v) the Company's Common Stock ceases to be quoted on the Nasdaq
National Market or listed on a national securities exchange or traded on an
established automated over-the-counter trading market in the United States.

A "Designated Event" shall not be deemed to have occurred if either:

                           (1)      the last Closing Sale Price of the Common
         Stock for each of at least five Trading Days within:

         (i)      the period of the ten consecutive Trading Days immediately
after the later of the Designated Event or the public announcement of the
Designated Event, in the case of a Designated Event resulting solely from a
Designated Event in clause (i) of the definition of Designated Event; or

         (ii)     the period of the ten consecutive Trading Days immediately
preceding the Designated Event, in the case of a Designated Event resulting from
a Designated Event in clauses (ii), (iii) or (iv) of the definition of
Designated Event;

         is at least equal to 105% of the quotient where the numerator is the
         Principal Amount and the denominator is the Conversion Rate in effect
         on each of such five Trading Days, with such calculation being made for
         each Trading Day; or

                           (2)      in the case of a merger or consolidation
         described in clause (iii) of the definition of Designated Event, at
         least 95% of the consideration, excluding cash payments for fractional
         shares and cash payments pursuant to dissenters' approval rights, in
         the merger or consolidation constituting the Designated Event, consists
         of common stock traded on a U.S. national securities exchange or quoted
         on the Nasdaq National Market (or which shall be so traded or quoted
         when issued or exchanged in connection with such Designated Event) and
         as a result of such transaction or transactions the Securities become
         convertible solely into such common stock.

"DESIGNATED EVENT PURCHASE DATE" has the meaning set forth in Section 5.1(a).

"DESIGNATED EVENT PURCHASE NOTICE" has the meaning set forth in Section 5.1(c).

"DESIGNATED EVENT PURCHASE PRICE" has the meaning set forth in Section 5.1(a).

"DESIGNATED SUBSIDIARY" means any existing or future, direct or indirect,
Subsidiary of the Company that would constitute a "significant subsidiary" as
such term is defined under Rule 1.02 of Regulation S-X.

"DISTRIBUTED ASSETS" has the meaning set forth in Section 12.3(d).

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

"EDGAR" has the meaning set forth in Section 6.2(b).

"EQUITY INTEREST" of any Person means any and all shares, interests, rights to
purchase, warrants, options, participations or other equivalents of or interests
in (however designated) corporate stock or other equity participations,
including partnership interests, whether general or limited, of such Person.

"EVENT OF DEFAULT" has the meaning set forth in Section 8.1.

"EXCESS AMOUNT" has the meaning set forth in Section 12.13(a).

"EXCHANGE ACT" means the United States Securities Exchange Act of 1934, as
amended.

"EX-DIVIDEND TIME" means, with respect to any issuance or distribution on Common
Stock, the first Trading Day on which the Common Stock trades regular way on the
principal securities market on which the Common Stock is then traded without the
right to receive such issuance or distribution.

"EXPIRATION TIME" has the meaning set forth in Section 12.3(e).

"FAIR MARKET VALUE" has the meaning set forth in Section 12.3(g).

"GLOBAL SECURITIES" means Securities that are in substantially the form attached
hereto as Exhibit A and that include the information called for by footnotes 1
and 3 thereof and that are deposited with the Depositary or its custodian and
registered in the name of, the Depositary or its nominee.

"HOLDER" means a person in whose name a Security is registered on the
Registrar's books.

"INDEBTEDNESS" means, with respect to any Person, without duplication, any
liability of such Person:

                  (a)      for borrowed money;

                                       3
<PAGE>

                  (b)      evidenced by bonds, debentures, notes;

                  (c)      in respect of letters of credit or bankers
         acceptances or similar instruments (or reimbursement obligations with
         respect thereto);

                  (d)      to pay the deferred purchase price of property or
         services, except trade accounts payable arising in the ordinary course
         of business;

                  (e)      as lessee, the obligations of which are capitalized
         in accordance with generally accepted accounting principles; and

                  (f)      for Indebtedness of others guaranteed by such Person
         or for which such Person is legally responsible or liable (whether by
         agreement to purchase indebtedness of, or to supply funds or to invest
         in, others).

The amount of Indebtedness of any Person at any date shall be (i) the
outstanding principal amount of all unconditional obligations described above,
as such amount would be reflected on a balance sheet prepared in accordance with
United States generally accepted accounting principles, and the maximum
liability at such date of such Person for any contingent obligations described
above, (ii) the accreted value thereof, in the case of any Indebtedness issued
with original issue discount, and (iii) the principal amount thereof, together
with any interest thereon that is more than 30 days past due, in the case of any
other Indebtedness.

"INDENTURE" means this Indenture, as amended or supplemented from time to time
in accordance with the terms hereof, including the provisions of the TIA that
are explicitly incorporated in this Indenture by reference to the TIA.

"INTEREST PAYMENT DATE" has the meaning set forth in Exhibit A attached hereto.

"ISSUE DATE" of any Security means the date on which such Security was
originally issued or deemed issued as set forth on the face of the Security.

"LEGAL HOLIDAY" means any day other than a Business Day.

"MARKET PRICE" means the average of the Closing Sale Prices of one share of
Applicable Stock for the 20-Trading Day period immediately preceding and
including the Business Day immediately preceding the Purchase Date or Designated
Event Purchase Date, as the case may be (or if the Business Day immediately
preceding the Purchase Date or Designated Event Purchase Date, as the case may
be, is not a Trading Day, then on the last Trading Day immediately preceding the
Business Day), appropriately adjusted to take into account the occurrence,
during the period commencing on the first of such Trading Days during such
20-Trading Day period and ending on the Purchase Date or Designated Event
Purchase Date, as the case may be, of any event described in Section 12.3 or
Section 12.4.

"NON-ELECTING SHARE" has the meaning set forth Section 12.4.

"OFFICER" means the Chief Executive Officer, the President, the Chief Financial
Officer, any Vice President, the Treasurer, or the Clerk of the Company.

"OFFICERS' CERTIFICATE" means a written certificate containing the information
specified in Section 13.4 and Section 13.5, signed in the name of the Company by
any two Officers, at least one of whom is the Chief Executive Officer or the
Chief Financial Officer, and delivered to the Trustee. An Officers' Certificate
given pursuant to Section 6.3 shall be signed by the Chief Financial Officer and
one other Officer.

"OPINION OF COUNSEL" means a written opinion containing the information
specified in Section 13.4 and Section 13.5, from legal counsel. The counsel may
be an employee of, or counsel to, the Company.

"PAYING AGENT" has the meaning set forth in Section 2.3.

"PERSON" or "PERSON" means any individual, corporation, limited liability
company, partnership, joint venture, association, joint-stock company, trust,
unincorporated organization, or government or any agency or political
subdivision thereof (and for purposes of the definition of "Designated Event"
shall also have the meaning set forth in such definition).

"PRINCIPAL AMOUNT" of a Security means the principal amount of the Security as
set forth on the face of the Security.

"PURCHASE DATE" has the meaning set forth in Section 4.1(a).

                                       4
<PAGE>

"PURCHASE NOTICE" has the meaning set forth in Section 4.1(c).

"PURCHASE PRICE" has the meaning set forth in Section 4.1(a).

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

"RECORD DATE" has the meaning set forth in Section 12.3(g).

"REDEMPTION DATE" means, when used with respect to any Security to be redeemed,
the date fixed for redemption pursuant to this Indenture.

"REDEMPTION PRICE" shall mean an amount equal to 100% of the Principal Amount of
the Securities to be redeemed plus any accrued and unpaid interest (including
Additional Interest, if any) to, but excluding, the Redemption Date.

"REFERENCE PERIOD" has the meaning set forth in Section 12.3(d).

"REGISTRAR" has the meaning set forth in Section 2.3.

"REGISTER" has the meaning set forth in Section 2.3.

"REGISTRATION RIGHTS AGREEMENT" means the Registration Rights Agreement, dated
December 8, 2003, between the Company and Bear, Stearns & Co. Inc., as amended
or supplemented from time to time.

"REGULAR RECORD DATE" has the meaning set forth in Exhibit A attached hereto.

"RELIANCE LETTER" means a letter from legal counsel to the Company authorizing
the Trustee to rely on certain provisions contained in that certain legal
opinion of such counsel, dated as of December 8, 2003, delivered to Bear,
Stearns & Co. Inc.

"RESPONSIBLE OFFICER" means, when used with respect to the Trustee, the officer
within the corporate trust department of the Trustee, including any vice
president, assistant vice president or assistant treasurer or any other officer
of the Trustee who customarily performs functions similar to those performed by
the persons who at the time shall be such officers, respectively, or to whom any
corporate trust matter is referred because of such person's knowledge of and
familiarity with the particular subject and who shall have direct responsibility
for the administration of this Indenture.

"RESTRICTED CERTIFICATED SECURITY" means a Certificated Security which is a
Transfer Restricted Security.

"RESTRICTED GLOBAL SECURITY" means a Global Security that is a Transfer
Restricted Security.

"RESTRICTED SECURITY" means a Restricted Certificated Security or a Restricted
Global Security.

"RULE 144A" means Rule 144A under the Securities Act (or any successor
provision), as it may be amended from time to time.

"SEC" means the United States Securities and Exchange Commission, or any
successor thereto.

"SECURITIES" means any of the Company's 3.0% Convertible Senior Notes due 2023,
as amended or supplemented from time to time, issued under this Indenture.

"SECURITIES ACT" means the United States Securities Act of 1933, as amended, or
any successor statute thereto.

"SPECIAL RECORD DATE" has the meaning set forth in Exhibit A attached hereto.

"SPIN-OFF" has the meaning set forth in Section 12.3(d).

"STATED MATURITY", when used with respect to any Security, means December 15,
2023.

"SUBSIDIARY" means any person of which at least a majority of the outstanding
Voting Stock shall at the time directly or indirectly be owned or controlled by
the Company or by one or more Subsidiaries or by the Company and one or more
Subsidiaries.

"TIA" means the United States Trust Indenture Act of 1939 as in effect on the
date of this Indenture, provided, however, that in the event the TIA is amended
after such date, TIA means, to the extent required by any such amendment, the
TIA as so amended.

"TRADING DAY" means a day during which trading in securities generally occurs on
the Nasdaq National Market system or, if the Applicable Stock is not quoted on
the Nasdaq National Market system, on the principal U.S. national or regional
securities exchange on which the Applicable Stock is then listed or, if the
Applicable Stock is not listed on a U.S. national or regional securities
exchange, and not quoted on the Nasdaq National Market system, on the principal
other market on which the Applicable Stock is then traded (provided that no day
on which trading of the Applicable Stock is suspended on such exchange or other
trading market will count as a Trading Day).

"TRANSFER CERTIFICATE" has the meaning set forth in Section 2.12(f).

"TRANSFER RESTRICTED SECURITY" has the meaning set forth in Section 2.12(f).

"TRIGGER EVENT" has the meaning set forth in Section 12.3(d).


                                       5
<PAGE>
"TRUSTEE" means the party named as the "Trustee" in the first paragraph of this
Indenture until a successor replaces it pursuant to the applicable provisions of
this Indenture and, thereafter, shall mean such successor. The foregoing
sentence shall likewise apply to any subsequent such successor or successors.

"UNRESTRICTED CERTIFICATED SECURITY" means a Certificated Security that is not a
Transfer Restricted Security.

"UNRESTRICTED GLOBAL SECURITY" means a Global Security that is not a Transfer
Restricted Security.

"VOTING STOCK" of a person means the Equity Interest of such person of the class
or classes pursuant to which the holders thereof have the general voting power
under ordinary circumstances to elect at least a majority of the board of
directors, managers or trustees of such person (irrespective of whether or not
at the time the Equity Interest of any other class or classes shall have or
might have voting power by reason of the happening of any contingency).

"WHOLLY OWNED SUBSIDIARY" means a Subsidiary all the Equity Interest of which is
owned by the Company or another Wholly Owned Subsidiary, other than directors'
qualifying shares.

Section 1.2. Incorporation by Reference of Trust Indenture Act.

Whenever this Indenture refers to a provision of the TIA, the provision is
incorporated by reference in and made a part of this Indenture. The following
TIA terms used in this Indenture have the following meanings:

"COMMISSION" means the SEC.

"INDENTURE SECURITIES" means the Securities.

"INDENTURE SECURITY HOLDER" means a Holder.

"INDENTURE TO BE QUALIFIED" means this Indenture.

"INDENTURE TRUSTEE" or "institutional trustee" means the Trustee.

"OBLIGOR" on the indenture securities means the Company.

All other TIA terms used but not defined in this Indenture that are defined by
the TIA, defined by TIA reference to another statute or defined by SEC rule have
the meanings assigned to them by such definitions.

Section 1.3. Rules of Construction.

Unless the context otherwise requires:

(a)  a term has the meaning assigned to it;

                  (b)      an accounting term not otherwise defined has the
         meaning assigned to it in accordance with accounting principles
         generally accepted in the United States as in effect from time to time;

                  (c)      "or" is not exclusive;

                  (d)      "including" means including, without limitation; and

                  (e)      words in the singular include the plural, and words
         in the plural include the singular.

Section 1.4. Acts of Holders.

(a)  Any request, demand, authorization, direction, notice, consent, waiver or
     other action provided by this Indenture to be given or taken by the Holders
     may be embodied in and evidenced by one or more instruments of
     substantially similar tenor signed by such Holders in person or by an 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, as described in Section 13.2. 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 conclusive in favor of the Trustee and the Company, if
     made in the manner provided in this Section 1.4.

                                       6
<PAGE>

(b)  The fact and date of the execution by any person of any such instrument or
     writing may be proved by the affidavit of a witness of such execution or by
     a certificate of a notary public or other officer authorized by law to take
     acknowledgments of deeds, certifying that the individual signing such
     instrument or writing acknowledged to such officer the execution thereof.
     Where such execution is by a signer acting in a capacity other than such
     signer's individual capacity, such certificate or affidavit shall also
     constitute sufficient proof of such signer's authority, if it so states.
     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.

(c)  The principal amount and certificate number of any Security and the
     ownership of Securities shall be proved by the Register maintained by the
     Registrar for the Securities.

(d)  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.

(e)  If the Company shall solicit from the Holders any request, demand,
     authorization, direction, notice, consent, waiver or other Act, the Company
     may, at its option, by or pursuant to a Board Resolution, fix in advance a
     record date for the determination of Holders entitled to give such request,
     demand, authorization, direction, notice, consent, waiver or other Act, but
     the Company shall have no obligation to do so. If such a record date is
     fixed, such request, demand, authorization, direction, notice, consent,
     waiver or other Act may be given before or after such record date, but only
     the Holders of record at the close of business on such record date shall be
     deemed to be Holders for the purposes of determining whether Holders of the
     requisite proportion of outstanding Securities have authorized or agreed or
     consented to such request, demand, authorization, direction, notice,
     consent, waiver or other Act, and for that purpose the outstanding
     Securities shall be computed as of such record date; provided that no such
     authorization, agreement or consent by the Holders on such record date
     shall be deemed effective unless it shall become effective pursuant to the
     provisions of this Indenture not later than six months after the record
     date.

                                   ARTICLE II

                                 THE SECURITIES

Section 2.1. Form and Dating.

The Securities shall be designated as the "3.0% Convertible Senior Notes due
2023" of the Company. The aggregate principal amount of Securities outstanding
at any time may not exceed $86,250,000 except as provided in Section 2.7.

The Securities and the Trustee's certificate of authentication shall be
substantially in the form of Exhibit A attached hereto, which is incorporated in
and made a part of this Indenture. The Securities may have notations, legends or
endorsements required by law, stock exchange rule or usage (provided that any
such notation, legend or endorsement required by usage is in a form acceptable
to the Company). The Company shall provide any such notations, legends or
endorsements to the Trustee in writing. Each Security shall be dated the date of
its authentication.

(a)  Restricted Global Securities. All of the Securities are being offered and
     sold within the United States to QIBs in reliance on Rule 144A and shall be
     issued, initially in the form of one or more Restricted Global Securities,
     which shall be deposited with the Trustee at its Corporate Trust Office, as
     custodian for the Depositary and registered in the name of DTC or the
     nominee thereof, duly executed by the Company and authenticated by the
     Trustee as hereinafter provided. The aggregate principal amount of the
     Restricted Global Securities may from time to time be increased or
     decreased by adjustments made on the records of the Trustee and the
     Depositary as hereinafter provided.

                                       7
<PAGE>

(b)  Global Securities in General. Each Global Security shall represent such of
     the outstanding Securities as shall be specified therein and each shall
     provide that it shall initially represent the aggregate amount of
     outstanding Securities stated thereon, but that the aggregate amount of
     outstanding Securities represented thereby may from time to time be reduced
     or increased, as appropriate, to reflect exchanges, redemptions,
     repurchases and conversions of such Securities.

Any adjustment of the aggregate principal amount of a Global Security to reflect
the amount of any increase or decrease in the amount of outstanding Securities
represented thereby shall be made by the Trustee in accordance with instructions
given by the Holder thereof as required by Section 2.12 and shall be made on the
records of the Trustee and the Depositary.

Neither any members of, or participants in, the Depositary (collectively, the
"AGENT MEMBERS") nor any other persons on whose behalf Agent Members may act
shall have any rights under this Indenture with respect to any Global Security
registered in the name of the Depositary or any nominee thereof, or under any
such Global Security, and the Depositary or such nominee, as the case may be,
may be treated by the Company, the Trustee and any agent of the Company or the
Trustee as the absolute owner and holder of such Global Security for all
purposes whatsoever. Notwithstanding the foregoing, nothing contained herein
shall (A) prevent the Company, the Trustee or any agent of the Company or the
Trustee from giving effect to any written certification, proxy or other
authorization furnished by the Depositary or such nominee, as the case may be,
or (B) impair, as between the Depositary, its Agent Members and any other person
on whose behalf an Agent Member may act, the operation of customary practices of
such Persons governing the exercise of the rights of a holder of any Security.

(c)  Certificated Securities. Certificated Securities shall be issued only under
     the limited circumstances provided in Section 2.12(a)(i).

Section 2.2. Execution and Authentication.

The Securities shall be executed on behalf of the Company by any Officer. The
signature of the Officer on the Securities may be manual or facsimile.

A Security bearing the manual or facsimile signature of an individual who was at
the time of the execution of the Security an Officer shall bind the Company,
notwithstanding that such individual has ceased to hold such office(s) prior to
the authentication and delivery of such Securities or did not hold such
office(s) at the date of authentication of such Securities.

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 duly executed by
the Trustee by manual signature of an authorized signatory, and such certificate
upon any Security shall be conclusive evidence, and the only evidence, that such
Security has been duly authenticated and delivered hereunder.

The Trustee shall authenticate and deliver the Securities for original issuance
in an aggregate principal amount of up to $86,250,000 upon one or more Company
Orders without any further action by the Company (other than as contemplated
below and in Section 13.4 and Section 13.5). The aggregate principal amount due
at the Stated Maturity of the Securities outstanding at any time may not exceed
the amount set forth in the foregoing sentence except as provided in Section
2.7. In authenticating such Securities, and accepting the additional
responsibilities under this Indenture in relation to such Securities, the
Trustee shall receive and shall be fully protected in relying upon:

                  (a)      a copy of the Board Resolution in or pursuant to
         which the terms and form of the Securities were established, the
         issuance and sale of the Securities was authorized, this Indenture was
         authorized and specified Officers were authorized to establish the form
         and determine the terms of the Securities and the form of this
         Indenture, to execute the Securities and this Indenture on behalf of
         the Company and to take any other necessary actions relating thereto
         and evidence of any actions taken by authorized Officers pursuant to
         that Board Resolution, certified by the Clerk, an Assistant Clerk or
         the General Counsel of the Company to have been duly adopted by the
         Board of Directors or taken by any authorized Officer and to be in full
         force and effect as of the date of such certificate; and

                  (b)      an Officer's Certificate delivered in accordance with
         to Section 13.4 and Section 13.5.

                                       8
<PAGE>

The Trustee shall act as the initial authenticating agent. Thereafter, the
Trustee may appoint an authenticating agent acceptable to the Company to
authenticate Securities. An authenticating agent may authenticate Securities
whenever the Trustee may do so. Each reference in this Indenture to
authentication by the Trustee includes authentication by such agent.

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

Section 2.3. Registrar, Paying Agent and Conversion Agent.

Pursuant to Section 6.5, the Company shall maintain an office or agency where
Securities may be presented for registration of transfer or for exchange
("REGISTRAR"), an office or agency where Securities may be presented for
redemption, repurchase or payment ("PAYING AGENT"), an office or agency where
Securities may be presented for conversion ("CONVERSION AGENT") and an office or
agency where notices and demands to or upon the Company in respect of the
Securities and this Indenture may be served. Pursuant to Section 6.5, the
Company shall at all times maintain a Registrar, Paying Agent, Conversion Agent
and an office or agency where notices and demands to or upon the Company in
respect of the Securities and this Indenture may be served in the Borough of
Manhattan, New York City. The Registrar shall keep a register of the Securities
(the "REGISTER") and of their transfer and exchange.

The Company may have one or more co-registrars, one or more additional paying
agents and one or more additional conversion agents. The term Paying Agent
includes any additional paying agent, including any named pursuant to Section
6.5. The term Conversion Agent includes any additional conversion agent,
including any named pursuant to Section 6.5.

The Company shall enter into an appropriate limited agency agreement with any
Registrar, Paying Agent, Conversion Agent or co-registrar (in each case, if such
Registrar, agent or co-registrar is a Person other than the Trustee). Each such
agreement shall implement the provisions of this Indenture that relate to such
agent. The Company shall notify the Trustee of the name and address of any such
agent. If the Company fails to maintain a Registrar or Paying Agent, the Trustee
shall act as such and shall be entitled to appropriate compensation therefor
pursuant to Section 9.7. The Company or any Subsidiary or an Affiliate of either
of them may act as Paying Agent, Registrar, Conversion Agent or co-registrar
and, if the Company fails to maintain a Conversion Agent, the Company shall act
as such.

The Company hereby initially appoints the Trustee as Registrar, Paying Agent and
Conversion Agent in connection with the Securities. The initial office of the
Registrar, Paying Agent and Conversion Agent shall be the office of the Trustee
that is located in the Borough of Manhattan, New York City, which office on the
date hereof is 520 Madison Avenue, 33rd Floor, New York, NY 10022.

Section 2.4. Paying Agent to Hold Cash and Securities in Trust.

Except as otherwise provided herein, prior to 10:00 a.m., New York City time, on
each due date of payments in respect of any Security, the Company shall deposit
with the Paying Agent, cash (in immediately available funds if deposited on the
due date) or number of shares of Applicable Stock, as applicable, sufficient to
make such payments when so becoming due. The Company shall require each Paying
Agent (other than the Trustee) to agree in writing that the Paying Agent shall
hold in trust for the benefit of Holders or the Trustee all cash and Applicable
Stock held by the Paying Agent for the making of payments in respect of the
Securities and shall notify the Trustee of any default by the Company in making
any such payment. If the Company, a Subsidiary or an Affiliate of either of them
acts as Paying Agent, it shall segregate the money and Applicable Stock held by
it as Paying Agent and hold it as a separate trust fund. The Company at any time
may require a Paying Agent to pay all cash and Applicable Stock held by it to
the Trustee, and to account for any funds and Applicable Stock disbursed by it,
and the Trustee may at any time during the continuance of any such default, upon
the written request to the Paying Agent, require such Paying Agent to forthwith
pay to the Trustee all cash and Applicable Stock so held in trust. Upon doing
so, the Paying Agent shall have no further liability for the cash or Applicable
Stock.

Section 2.5. Holder Lists.

The Trustee shall preserve in as current a form as is reasonably practicable the
most recent list available to it of the names and addresses of Holders. If the
Trustee is not the Registrar, the Company shall cause to be furnished to the
Trustee on or before each semiannual interest payment date and at such other
times as the Trustee may request in writing a list in such form and as of such
date as the Trustee may

                                       9
<PAGE>
reasonably require of the names and addresses of Holders.

Section 2.6. Transfer and Exchange.

(a)  Subject to compliance with any applicable additional requirements contained
     in Section 2.12, when a Security is presented to the Registrar with a
     request to register a transfer thereof or to exchange such Security for an
     equal principal amount of Securities of other authorized denominations, the
     Registrar shall register the transfer or make the exchange as requested;
     provided, however, that every Security presented or surrendered for
     registration of transfer or exchange shall be duly endorsed or accompanied
     by an assignment form and, if applicable, a transfer certificate, each in
     the form included in Exhibit A attached hereto and in form satisfactory to
     the Registrar and each duly executed by the Holder thereof or its attorney
     duly authorized in writing. To permit registration of transfers and
     exchanges, upon surrender of any Security for registration of transfer or
     exchange at an office or agency maintained for such purpose pursuant to
     Section 2.3, the Company shall execute, and the Trustee shall authenticate,
     Securities of a like aggregate principal amount at the Registrar's request.
     Any transfer or exchange shall be without charge, except that the Company
     or the Registrar may require payment of a sum sufficient to pay all taxes,
     assessments or other governmental charges that may be imposed in connection
     with the transfer or exchange of the Securities from the Holder requesting
     such transfer or exchange.

     Neither the Company, the Registrar nor the Trustee shall be required to
     exchange or register a transfer of (i) any Securities selected for
     redemption (except, in the case of Securities to be redeemed in part, the
     portion thereof not to be redeemed), or (ii) any Securities in respect of
     which a Purchase Notice or a Designated Event Purchase Notice has been
     given and not withdrawn by the Holder thereof in accordance with the terms
     of this Indenture (except, in the case of Securities to be repurchased in
     part, the portion thereof not to be repurchased), or (iii) any Securities
     surrendered for conversion (except, in the case of Securities to be
     converted in part, the portion thereof not to be converted).

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

(b)  Any Registrar appointed pursuant to Section 2.3 shall provide to the
     Trustee such information as the Trustee may reasonably require in
     connection with the delivery by such Registrar of Securities upon transfer
     or exchange of Securities.

(c)  The Trustee shall have no obligation or duty to monitor, determine or
     inquire as to compliance with any restrictions on transfer imposed under
     this Indenture or under applicable law with respect to any transfer of any
     interest in any Security (including any transfers between or among Agent
     Members or other beneficial owners of interests in any Global Security)
     other than to require delivery of such certificates and other documentation
     or evidence as are expressly required by, and to do so if and when
     expressly required by the terms of, this Indenture, and to examine the same
     to determine substantial compliance as to form with the express
     requirements hereof.

Section 2.7. Replacement Securities.

If (a) any mutilated Security is surrendered to the Company, the Registrar or
the Trustee, or (b) the Company, the Registrar and the Trustee receive evidence
to their satisfaction of the destruction, loss or theft of any Security, and
there is delivered to the Company, the Registrar and the Trustee such security
or indemnity as may be required by them to save each of them harmless, then, in
the absence of notice to the Company, the Registrar or the Trustee that such
Security has been acquired by a bona fide purchaser, the Company shall execute
and upon its written request the Trustee shall authenticate and deliver, in
exchange for any such mutilated Security or in lieu of any such destroyed, lost
or stolen Security, a new Security of like tenor and principal amount, bearing a
certificate number not contemporaneously outstanding.

In case any such mutilated, destroyed, lost or stolen Security has become or is
about to become due and payable, or is about to be redeemed by the Company
pursuant to Article III or repurchased by the Company pursuant to Article IV or
Article V, the Company in its discretion may, instead of issuing a new

                                       10
<PAGE>

Security, pay, redeem or repurchase such Security, as the case may be.

Upon the issuance of any new Securities under this Section 2.7, the Company may
require the payment of a sum sufficient to cover any tax, assessment or other
governmental charge that may be imposed in relation thereto and any other
expenses (including the fees and expenses of the Trustee or the Registrar)
connected therewith.

Every new Security issued pursuant to this Section 2.7 in lieu of any mutilated,
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 benefits of this Indenture equally and proportionately with any
and all other Securities duly issued hereunder.

The provisions of this Section 2.7 are exclusive and shall preclude (to the
extent lawful) all other rights and remedies with respect to the replacement or
payment of mutilated, destroyed, lost or stolen Securities.

Section 2.8. Outstanding Securities; Determinations of Holders' Action.

Securities outstanding at any time are all the Securities authenticated by the
Trustee, except for

(a)  those cancelled by it,

(b)  those paid, redeemed or repurchased pursuant to Section 2.7,

(c)  those delivered to it for cancellation, and

(d)  those described in this Section 2.8 as not outstanding.

A Security does not cease to be outstanding because the Company or an Affiliate
thereof holds the Security; provided, however, that in determining whether the
Holders of the requisite principal amount of Securities have given or concurred
in any request, demand, authorization, direction, notice, consent, waiver, or
other Act hereunder, Securities owned by the Company or any other obligor upon
the Securities or any Affiliate of the Company or such other obligor shall be
disregarded and deemed not to be outstanding, except that, in determining
whether the Trustee shall be protected in relying upon any such request, demand,
authorization, direction, notice, consent, waiver or other Act, only Securities
which a Responsible Officer of the Trustee actually knows to be so owned shall
be so disregarded. Subject to the foregoing, only Securities outstanding at the
time of such determination shall be considered in any such determination.

If a Security is replaced pursuant to Section 2.7, the replaced Security ceases
to be outstanding unless the Trustee receives proof satisfactory to it that the
replaced Security is held by a bona fide purchaser unaware that such Security
has been replaced.

If the Paying Agent holds, in accordance with the terms of this Indenture, prior
to 10:00 a.m., New York City time, on a Redemption Date, a Purchase Date, a
Designated Event Purchase Date or Stated Maturity, as the case may be, cash or
securities, if permitted hereunder, sufficient to pay Securities payable on that
date, then on such Redemption Date, Purchase Date, Designated Event Purchase
Date or Stated Maturity, as the case may be, such Securities shall cease to be
outstanding and interest and Additional Interest, if any, on such Securities
shall cease to accrue.

If a Security is converted in accordance with Article XII, then from and after
the time of conversion on the date of conversion, such Security shall cease to
be outstanding and interest and Additional Interest, if any, on such Security
shall cease to accrue.

Section 2.9. Temporary Securities.

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

If temporary Securities are issued, the Company shall cause definitive
Securities to be prepared without unreasonable delay. After the preparation of
definitive Securities, the temporary Securities shall be

                                       11
<PAGE>

exchangeable for definitive Securities upon surrender of the temporary
Securities at the office or agency of the Company designated for such purpose
pursuant to Section 2.3, without charge to the Holder. Upon surrender for
cancellation of any one or more temporary Securities the Company shall execute
and the Trustee shall authenticate and deliver in exchange therefor a like
principal amount of definitive Securities of authorized denominations. Until so
exchanged the temporary Securities shall in all respects be entitled to the same
benefits and subject to the same limitations under this Indenture as definitive
Securities.

Section 2.10. Cancellation.

All Securities surrendered for payment, repurchase by the Company pursuant to
Article IV or Article V, conversion, redemption or registration of transfer or
exchange shall, if surrendered to any person other than the Trustee, be
delivered to the Trustee and shall be promptly cancelled by it or, if
surrendered to the Trustee, shall be promptly cancelled by it. The Company may
at any time deliver to the Trustee for cancellation any Securities previously
authenticated and delivered hereunder which the Company may have acquired in any
manner whatsoever, and all Securities so delivered shall be promptly cancelled
by the Trustee. The Company may not issue new Securities to replace Securities
it has paid or delivered to the Trustee for cancellation or that any Holder has
converted pursuant to Article XII No Securities shall be authenticated in lieu
of or in exchange for any Securities cancelled as provided in this Section 2.10,
except as expressly permitted by this Indenture. All cancelled Securities held
by the Trustee shall be disposed of by the Trustee in accordance with the
Trustee's customary procedure.

Section 2.11. Persons Deemed Owners.

Prior to due presentment of a Security for registration of transfer, the
Company, the Trustee, any Paying Agent and any agent of the Company, the Trustee
or the Paying Agent may treat the person in whose name such Security is
registered as the owner of such Security for the purpose of receiving payment
(whether in cash or Applicable Stock) of principal of, Redemption Price,
Purchase Price or Designated Event Purchase Price, and interest and Additional
Interest, if any, on, the Security, for the purpose of receiving cash or
Applicable Stock upon conversion 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 2.12. Additional Transfer and Exchange Requirements.

(a)  Transfer and Exchange of Global Securities.

     (i)  Certificated Securities shall be issued in exchange for interests in
          the Global Securities only if (x) the Depositary notifies the Company
          that it is unwilling or unable to continue as Depositary for the
          Global Securities or if it at any time ceases to be a "clearing
          agency" registered under the Exchange Act, if so required by
          applicable law or regulation and a successor Depositary is not
          appointed by the Company within 90 calendar days, or (y) an Event of
          Default has occurred and is continuing and the Registrar has received
          a request from the Depositary requesting such exchange. In either
          case, the Company shall execute, and the Trustee shall, upon receipt
          of a Company Order (which the Company agrees to deliver promptly),
          authenticate and deliver Certificated Securities in an aggregate
          principal amount equal to the principal amount of such Global
          Securities in exchange therefor. Only Restricted Certificated
          Securities shall be issued in exchange for beneficial interests in
          Restricted Global Securities, and only Unrestricted Certificated
          Securities shall be issued in exchange for beneficial interests in
          Unrestricted Global Securities. Certificated Securities issued in
          exchange for beneficial interests in Global Securities shall be
          registered in such names and shall be in such authorized denominations
          as the Depositary, pursuant to instructions from its direct or
          indirect participants or otherwise, shall instruct the Trustee. The
          Trustee shall deliver or cause to be delivered such Certificated
          Securities to the Persons in whose name such Securities are so
          registered. Such exchange shall be effected in accordance with the
          Applicable Procedures.

     (ii) Notwithstanding any other provisions of this Indenture other than the
          provisions set forth in Section 2.12(a)(i), a Global Security may not
          be transferred except as a whole by the Depositary to a nominee of the
          Depositary or by a nominee of the Depositary to the Depositary or
          another nominee of the Depositary or by the Depositary or any such
          nominee to a successor Depositary or a nominee of such successor
          Depositary.

                                       12
<PAGE>

(b)  Transfer and Exchange of Certificated Securities. In the event that
     Certificated Securities are issued in exchange for beneficial interests in
     Global Securities in accordance with Section 2.12(a)(i), and, on or after
     such event, Certificated Securities are presented by a Holder to the
     Registrar with a request:

                  (x)      to register the transfer of the Certificated
         Securities to a person who shall take delivery thereof in the form of
         Certificated Securities only; or

                  (y)      to exchange such Certificated Securities for an equal
         principal amount of Certificated Securities of other authorized
         denominations,

such Registrar shall register the transfer or make the exchange as requested;
provided, however, that the Certificated Securities presented or surrendered for
register of transfer or exchange:

     (i)  shall be duly endorsed or accompanied by a written instrument of
          transfer in accordance with the proviso to the first paragraph of
          Section 2.6; and

     (ii) in the case of a Restricted Certificated Security, such request shall
          be accompanied by the following additional information and documents,
          as applicable:

          (A)  if such Restricted Certificated Security is being delivered to
               the Registrar by a Holder for registration in the name of such
               Holder, without transfer, or such Restricted Certificated
               Security is being transferred to the Company or a Subsidiary of
               the Company, a certification to that effect from such Holder (in
               substantially the form set forth in the Transfer Certificate);

          (B)  if such Restricted Certificated Security is being transferred to
               a person the Holder reasonably believes is a QIB in accordance
               with Rule 144A or pursuant to an effective registration statement
               under the Securities Act, a certification to that effect from
               such Holder (in substantially the form set forth in the Transfer
               Certificate); or

          (C)  if such Restricted Certificated Security is being transferred
               pursuant to an exemption from the registration requirements of
               the Securities Act in accordance with Rule 144 or to an
               institutional "accredited investor" (as defined in Rule
               501(a)(1), (2), (3) or (7) of Regulation D under the Securities
               Act) pursuant to and in compliance with an exemption from the
               registration requirements under the Securities Act, a
               certification to that effect from the Holder (in substantially
               the form set forth in the Transfer Certificate) and, in the case
               of a transfer to an institutional accredited investor, a
               certificate containing certain representations and warranties (in
               substantially the form set forth in Exhibit B) and, in either
               case, if the Company or the Registrar so requests, a customary
               Opinion of Counsel, certificates and other information reasonably
               acceptable to the Company and the Registrar to the effect that
               such transfer does not require registration under the Securities
               Act.

(c)  Transfer of a Beneficial Interests in a Restricted Global Security for a
     Beneficial Interest in an Unrestricted Global Security. Any person having a
     beneficial interest in a Restricted Global Security may upon request,
     subject to the Applicable Procedures, transfer such beneficial interest to
     a person who is required or permitted to take delivery thereof in the form
     of an Unrestricted Global Security. Upon receipt by the Trustee of written
     instructions, or such other form of instructions as is customary for the
     Depositary, from the Depositary or its nominee on behalf of any person
     having a beneficial interest in a Restricted Global Security and the
     following additional information and documents in such form as is customary
     for the Depositary from the Depositary or its nominee on behalf of the
     person having such beneficial interest in the Restricted Global Security
     (all of which may be submitted by facsimile or electronically):

     (i)  if such beneficial interest is being transferred pursuant to an
          effective registration statement under the Securities Act, a
          certification to that effect from the Holder (in substantially the
          form set forth in the Transfer Certificate); or

     (ii) if such beneficial interest is being transferred pursuant to an
          exemption from the registration requirements of the Securities Act in
          accordance with Rule 144, a certification to that effect from the
          Holder (in substantially the form set forth in the Transfer
          Certificate) and, if the Company or the Trustee so requests, a
          customary Opinion

                                       13
<PAGE>

     of Counsel, certificates and other information reasonably acceptable to the
     Company and the Trustee to the effect that such transfer does not require
     registration under the Securities Act,

     the Trustee, as the Registrar, shall reduce or cause to be reduced the
     aggregate principal amount of the Restricted Global Security by the
     appropriate principal amount and shall increase or cause to be increased
     the aggregate principal amount of the Unrestricted Global Security by a
     like principal amount. Such transfer shall otherwise be effected in
     accordance with the Applicable Procedures. If no Unrestricted Global
     Security is then outstanding, the Company shall execute and the Trustee
     shall, upon receipt of a Company Order (which the Company agrees to deliver
     promptly), authenticate and deliver an Unrestricted Global Security.

(d)  Transfer of a Beneficial Interest in an Unrestricted Global Security for a
     Beneficial Interest in a Restricted Global Security. Any person having a
     beneficial interest in an Unrestricted Global Security may upon request,
     subject to the Applicable Procedures, transfer such beneficial interest to
     a person who is required or permitted to take delivery thereof in the form
     of a Restricted Global Security (it being understood that only QIBs may own
     beneficial interests in Restricted Global Securities). Upon receipt by the
     Trustee of written instructions, or such other form of instructions as is
     customary for the Depositary, from the Depository or its nominee on behalf
     of any person having a beneficial interest in an Unrestricted Global
     Security and the following additional information and documents in such
     form as is customary for the Depositary, from the Depositary or its nominee
     on behalf of the person having such beneficial interest in the Unrestricted
     Global Security (all of which may be submitted by facsimile or
     electronically): a certification from the Holder (in substantially the form
     set forth in the Transfer Certificate) to the effect that such beneficial
     interest is being transferred to a person that the transferor reasonably
     believes is a QIB in accordance with Rule 144A. The Trustee, as the
     Registrar, shall reduce or cause to be reduced the aggregate principal
     amount of the Unrestricted Global Security by the appropriate principal
     amount and shall increase or cause to be increased the aggregate principal
     amount of the Restricted Global Security by a like principal amount. Such
     transfer shall otherwise be effected in accordance with the Applicable
     Procedures. If no Restricted Global Security is then outstanding, the
     Company shall execute and the Trustee shall, upon receipt of a Company
     Order (which the Company agrees to deliver promptly), authenticate and
     deliver a Restricted Global Security.

(e)  Transfers of Certificated Securities for Beneficial Interest in Global
     Securities. In the event that Certificated Securities are issued in
     exchange for beneficial interests in Global Securities and, thereafter, the
     events or conditions specified in Section 2.12(a)(i) which required such
     exchange shall cease to exist, the Company shall mail notice to the Trustee
     and to the Holders stating that Holders may exchange Certificated
     Securities or interests in Global Securities by complying with the
     procedures set forth in this Indenture and briefly describing such
     procedures and the events or circumstances requiring that such notice be
     given. Thereafter, if Certificated Securities are presented by a Holder to
     a Registrar with a request:

                  (x)      to register the transfer of such Certificated
         Securities to a person who shall take delivery thereof in the form of a
         beneficial interest in a Global Security, which request shall specify
         whether such Global Security shall be a Restricted Global Security or
         an Unrestricted Global Security, or

                  (y)      to exchange such Certificated Securities for an equal
         principal amount of beneficial interests in a Global Security, which
         beneficial interests shall be owned by the Holder transferring such
         Certificated Securities (provided that in the case of such an exchange,
         Restricted Certificated Securities may be exchanged only for Restricted
         Global Securities and Unrestricted Certificated Securities may be
         exchanged only for Unrestricted Global Securities), the Registrar shall
         register the transfer or make the exchange as requested by canceling
         such Certificated Security and causing, or directing the Registrar to
         cause, the aggregate principal amount of the applicable Global Security
         to be increased accordingly and, if no such Global Security is then
         outstanding, the Company shall issue and the Trustee shall, upon
         receipt of a Company Order (which the Company agrees to deliver
         promptly) authenticate and deliver a new Global Security;

     provided, however, that the Certificated Securities presented or
     surrendered for registration of transfer or exchange:

     (1)  shall be duly endorsed or accompanied by a written instrument of
          transfer in accordance with the proviso to the first paragraph of
          Section 2.6;

                                       14
<PAGE>
     (2)  in the case of a Restricted Certificated Security to be transferred
          for a beneficial interest in an Unrestricted Global Security, such
          request shall be accompanied by the following additional information
          and documents, as applicable:

          (i)  if such Restricted Certificated Security is being transferred
               pursuant to an effective registration statement under the
               Securities Act, a certification to that effect from such Holder
               (in substantially the form set forth in the Transfer
               Certificate); or

          (ii) if such Restricted Certificated Security is being transferred
               pursuant to an exemption from the registration requirements of
               the Securities Act in accordance with Rule 144, a certification
               to that effect from such Holder (in substantially the form set
               forth in the Transfer Certificate) and, if the Company or the
               Registrar so requests, a customary Opinion of Counsel,
               certificates and other information reasonably acceptable to the
               Company and the Trustee to the effect that such transfer does not
               require registration under the Securities Act;

     (3)  in the case of a Restricted Certificated Security to be transferred or
          exchanged for a beneficial interest in a Restricted Global Security,
          such request shall be accompanied by a certification from such Holder
          (in substantially the form set forth in the Transfer Certificate) to
          the effect that such Restricted Certificated Security is being
          transferred to a person the Holder reasonably believes is a QIB
          (which, in the case of an exchange, shall be such Holder) in
          accordance with Rule 144A;

     (4)  in the case of an Unrestricted Certificated Security to be transferred
          or exchanged for a beneficial interest in an Unrestricted Global
          Security, such request need not be accompanied by any additional
          information or documents; and

     (5)  in the case of an Unrestricted Certificated Security to be transferred
          or exchanged for a beneficial interest in a Restricted Global
          Security, such request shall be accompanied by a certification from
          such Holder (in substantially, the form set forth in the Transfer
          Certificate) to the effect that such Unrestricted Certificated
          Security is being transferred to a person the Holder reasonably
          believes is a QIB (which, in the case of an exchange, shall be such
          Holder) in accordance with Rule 144A.

(f)  Legends.

     (1)  Except as permitted by the following paragraphs (2), (3) and (4), each
          Global Security and Certificated Security (and all Securities issued
          in exchange therefor or upon registration of transfer or replacement
          thereof) shall bear a legend in substantially the form called for by
          footnote 2 to Exhibit A attached hereto (each a "TRANSFER RESTRICTED
          SECURITY"), for so long as it is required by this Indenture to bear
          such legend. Each Transfer Restricted Security shall have attached
          thereto a certificate (a "TRANSFER CERTIFICATE") in substantially the
          form called for by footnote 4 to Exhibit A attached hereto.

     (2)  Upon any sale or transfer of a Transfer Restricted Security (x) after
          the expiration of the holding period applicable to sales of the
          Securities under Rule 144(k) of the Securities Act, (y) pursuant to
          Rule 144 or (z) pursuant to an effective registration statement under
          the Securities Act:

          (i)  in the case of any Restricted Certificated Security, any
               Registrar shall permit the Holder thereof to exchange such
               Restricted Certificated Security for an Unrestricted Certificated
               Security, or (under the circumstances described in Section
               2.12(e)) to transfer such Restricted Certificated Security to a
               transferee who shall take such Security in the form of a
               beneficial interest in an Unrestricted Global Security, and in
               each case shall rescind any restriction on the transfer of such
               Security; provided, however, that the Holder of such Restricted
               Certificated Security shall, in connection with such exchange or
               transfer, comply with the other applicable provisions of this
               Section 2.12; and

          (ii) in the case of any beneficial interest in a Restricted Global
               Security, the Trustee shall permit the beneficial owner thereof
               to transfer such beneficial interest to a transferee who shall
               take such interest in the form of a

                                       15
<PAGE>
               beneficial interest in an Unrestricted Global Security and shall
               rescind any restriction on transfer of such beneficial interest;
               provided, that such Unrestricted Global Security shall continue
               to be subject to the provisions of Section 2.12(a)(ii); and
               provided, further, that the owner of such beneficial interest
               shall, in connection with such transfer, comply with the other
               applicable provisions of this Section 2.12.

     (3)  Upon the exchange, registration of transfer or replacement of
          Securities not bearing the legend described in paragraph (1) above,
          the Company shall execute, and the Trustee shall authenticate and
          deliver Securities that do not bear such legend and that do not have a
          Transfer Certificate attached thereto.

     (4)  After the expiration of the holding period pursuant to Rule 144(k) of
          the Securities Act, the Company may with the consent of the Holder of
          a Restricted Global Security or a Restricted Certificated Security,
          remove any restriction of transfer on such Security, and the Company
          shall execute, and the Trustee shall authenticate and deliver
          Securities that do not bear such legend and that do not have a
          Transfer Certificate attached thereto.

     (5)  Until the expiration of the holding period applicable to sales of the
          Securities under Rule 144(k) of the Securities Act or a transfer
          pursuant to Rule 144 or pursuant to an effective registration
          statement under the Securities Act, the Applicable Stock issued upon
          conversion of the Securities shall bear the legend in substantially
          the form called for by Exhibit C attached hereto.

(g)  Transfers to the Company. Nothing contained in this Indenture or in the
     Securities shall prohibit the sale or other transfer of any Securities
     (including beneficial interests in Global Securities) to the Company or any
     of its Subsidiaries, which Securities shall thereupon be cancelled in
     accordance with Section 2.10.

(h)  Amendments to Rule 144(k). Notwithstanding any other provision in this
     Indenture, if Rule 144(k) as promulgated under the Securities Act is
     amended to shorten the two-year period under Rule 144(k), then the
     references to "two years" in the restrictive legend of each Transfer
     Restricted Security and footnote one to Exhibit A shall be deemed to refer
     to such shorter period, from and after receipt by the Trustee of the
     documents described in Section 2.12(e)(2) from the Company or from a Holder
     of a Transfer Restricted Security; provided that, Transfer Restricted
     Security shall not be deemed to refer to such shorter period if to do so
     would be prohibited by, or would otherwise cause a violation of, the U.S.
     federal securities laws applicable at the time. As soon as practicable
     after a Responsible Officer of the Company receives notice of the
     effectiveness of any such amendment to shorten the two-year period under
     Rule 144(k), unless causing the Transfer Restricted Securities to refer to
     such shorter period would otherwise be prohibited by, or would otherwise
     cause a violation of, the U.S. federal securities laws applicable at the
     time, the Company will provide to the Trustee the documents described in
     Section 2.12(e)(2) respecting the effectiveness of such amendment.

Section 2.13. CUSIP Numbers.

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

Section 2.14. Ranking.

The indebtedness of the Company arising under or in connection with this
Indenture and every outstanding Security issued under this Indenture from time
to time constitutes and shall constitute a senior unsecured general obligation
of the Company, ranking equally in right of payment with other existing and
future senior unsecured Indebtedness of the Company and ranking senior in right
of payment to any future Indebtedness of the Company that is expressly made
subordinate to the Securities by the terms of such Indebtedness.

                                       16
<PAGE>

                                  ARTICLE III

                                   REDEMPTION

Section 3.1. The Company's Right to Redeem; Notice to Trustee.

Prior to December 15, 2008, the Securities shall not be redeemable at the
Company's option. On or after December 15, 2008, the Company, at its option, may
redeem the Securities in accordance with this Article III for cash at any time
as a whole, or from time to time in part, at the Redemption Price.

In the event that the Company elects to redeem the Securities on a date that is
after any Regular Record Date but on or before the corresponding Interest
Payment Date, the Company shall be required to pay any accrued and unpaid
interest and Additional Interest, if any, to the holder of the redeemed Security
and not the Holder on the corresponding Regular Record Date.

If the Company elects to redeem Securities, it shall notify the Trustee in
writing of the Redemption Date, the principal amount of Securities to be
redeemed and the Redemption Price. The Company shall give this notice to the
Trustee by a Company Order at least 30 days before the Redemption Date (unless a
shorter notice shall be satisfactory to the Trustee).

Section 3.2. Selection of Securities to Be Redeemed.

If fewer than all of the outstanding Securities are to be redeemed, unless the
procedures of the Depositary provide otherwise, the Trustee shall select the
Securities to be redeemed by lot or on a pro rata basis or by another method the
Trustee considers fair and appropriate. The Trustee shall make the selection
within five Business Days after it receives the notice provided for in Section
3.1 from outstanding Securities not previously called for redemption.

Securities and portions of Securities that the Trustee selects shall be in
principal amounts of $1,000 or an integral multiple of $1,000. Provisions of
this Indenture that apply to Securities called for redemption also apply to
portions of Securities called for redemption. The Trustee shall notify the
Company promptly of the Securities or portions of the Securities to be redeemed.

Securities and portions of Securities that are to be redeemed are convertible by
the Holder until 5:00 p.m., New York City time, on the second Business Day
immediately preceding the Redemption Date. If any Security selected for partial
redemption is converted in part before termination of the conversion right with
respect to the portion of the Security so selected, the converted portion of
such Security shall be deemed (so far as may be) to be the portion selected for
redemption and the Trustee shall select additional Securities to be redeemed in
the manner provided in the first paragraph of this Section 3.2 in an amount
equal to the Securities that would have been redeemed but for their conversion
prior to the termination of their conversion right. Securities which have been
converted during a selection of Securities to be redeemed may be treated by the
Trustee as outstanding for the purpose of such selection.

Section 3.3. Notice of Redemption.

At least 20 calendar days but not more than 60 calendar days before a Redemption
Date, the Company shall mail a notice of redemption by first-class mail, postage
prepaid, to each Holder of Securities to be redeemed. The notice of redemption
shall identify the Securities to be redeemed and shall state:

          (a)  the Redemption Date;

          (b)  the Redemption Price;

          (c)  the Conversion Rate and any adjustments thereto;

          (d)  the name and address of the Paying Agent and Conversion Agent;

          (e)  that Securities called for redemption may be converted at any
     time prior to 5:00 p.m., New York City time, on the second Business Day
     preceding the Redemption Date;

                                       17
<PAGE>

          (f)  that Holders who want to convert their Securities must satisfy
     the requirements set forth in Article XII;

          (g)  that Securities called for redemption must be surrendered to the
     Paying Agent to collect the Redemption Price;

          (h)  if fewer than all of the outstanding Securities are to be
     redeemed, the certificate numbers, if any, and principal amounts of the
     particular Securities to be redeemed;

          (i)  that, unless the Company defaults in making payment of such
     Redemption Price, interest and Additional Interest, if any, on Securities
     called for redemption shall cease to accrue on and after the Redemption
     Date;

          (j)  the CUSIP number(s) of the Securities; and

          (k)  any other information the Company wants to present.

At the Company's request, the Trustee shall give the notice of redemption in the
Company's name and at the Company's expense; provided, however, that the Company
makes such request at least five Business Days (unless a shorter period shall be
satisfactory to the Trustee) prior to the date by which such notice of
redemption must be given to Holders in accordance with this Section 3.3;
provided, further, that the text of the notice of redemption shall be prepared
by the Company.

Section 3.4. Effect of Notice of Redemption.

Once notice of redemption is given, Securities called for redemption become due
and payable on the Redemption Date and at the Redemption Price, except for
Securities which are converted in accordance with the terms of this Indenture.
Upon surrender to the Paying Agent, such Securities shall be paid at the
Redemption Price.

Section 3.5. Deposit of Redemption Price.

Prior to 10:00 a.m., New York City time, on the applicable Redemption Date, the
Company shall deposit with the Paying Agent (or if the Company or a Subsidiary
or an Affiliate of either of them is acting as the Paying Agent, shall segregate
and hold in trust as provided in Section 2.4) an amount of cash (in immediately
available funds if deposited on the Redemption Date) sufficient to pay the
aggregate Redemption Price of all Securities or portions thereof which are to be
redeemed as of such Redemption Date other than Securities or portions of
Securities called for redemption which on or prior thereto have been delivered
by the Company to the Trustee for cancellation or have been converted.

If the Paying Agent holds, in accordance with the terms hereof, at 10:00 a.m.,
New York City time, on the applicable Redemption Date, cash sufficient to pay
the Redemption Price of any Securities for which notice of redemption is given,
then, on such Redemption Date, such Securities shall cease to be outstanding and
interest and Additional Interest, if any, on such Securities shall cease to
accrue, whether or not such Securities are delivered to the Paying Agent, and
the rights of the Holders in respect thereof shall terminate (other than the
right to receive the Redemption Price upon delivery of such Securities).

Section 3.6. Securities Redeemed in Part.

Any Certificated Security which is to be redeemed only in part shall be
surrendered at the office of the Paying Agent and the Company shall execute and
the Trustee shall authenticate and deliver to the Holder of such Security,
without charge, a new Security or Securities, of any authorized denomination as
requested by such Holder in aggregate principal amount equal to the unredeemed
portion of the Security surrendered.

Section 3.7. Repayment to the Company.

To the extent that the aggregate amount of cash deposited by the Company
pursuant to Section 3.5 exceeds the aggregate Redemption Price of the Securities
or portions thereof which the Company is

                                       18
<PAGE>

redeeming as of the Redemption Date, then, promptly after the Redemption Date,
the Paying Agent shall return any such excess to the Company together with
interest, if any, thereon.

Section 3.8. No Sinking Fund.

The Securities shall not have a sinking fund.

                                   ARTICLE IV

                        PURCHASE AT THE OPTION OF HOLDERS
                                ON SPECIFIC DATES

Section 4.1. Optional Put.

(a)  Each Holder shall have the right, at the Holder's option, but subject to
     the provisions of this Section 4.1, to require the Company to purchase, and
     upon the exercise of such right, the Company shall purchase, all of such
     Holder's Securities not theretofore called for redemption, or any portion
     of the Principal Amount thereof that is equal to $1,000 or an integral
     multiple thereof, as directed by such Holder pursuant to this Section 4.1,
     on each of December 15, 2008, December 15, 2013 and December 15, 2018 (each
     a "PURCHASE DATE"). The Company shall be required to purchase such
     Securities at a purchase price in cash equal to 100% of the Principal
     Amount plus any accrued and unpaid cash interest (including any Additional
     Interest) to, but excluding, the Purchase Date (the "PURCHASE PRICE"). In
     the event that a Holder elects to require the Company to purchase such
     Holder's Securities, the Company shall be required to pay accrued and
     unpaid interest and Additional Interest, if any, to the holder of the
     repurchased Securities and not to the Holder on the Regular Record Date.

(b)  No later than 22 Business Days prior to each Purchase Date, the Company
     shall mail a written notice of the purchase right by first class mail to
     the Trustee (and the Paying Agent if the Trustee is not then acting as a
     Paying Agent) and to each Holder at its address shown in the Register of
     the Registrar, and to beneficial owners as required by applicable law. The
     notice shall include a form of Purchase Notice to be completed by the
     Holder and shall briefly state, as applicable:

     (i)    the date by which the Purchase Notice must be delivered to the
            Paying Agent in order for a Holder to exercise the purchase right
            pursuant to this Section 4.1;

     (ii)   the Purchase Date;

     (iii)  the Purchase Price;

     (iv)   the name and address of the Paying Agent and the Conversion Agent;

     (v)    the Conversion Rate and any adjustments thereto;

     (vi)   that the Securities as to which a Purchase Notice has been given may
            be converted into Common Stock if they are otherwise convertible
            pursuant to Article XII of this Indenture only if the Purchase
            Notice has been withdrawn in accordance with the terms of this
            Indenture;

     (vii)  that the Securities must be surrendered to the Paying Agent to
            collect payment;

     (viii) that the Purchase Price for any Security as to which a Purchase
            Notice has been duly given and not withdrawn shall be paid promptly
            following the later of the Purchase Date and the time of surrender
            of such Security as described in Section 4.1(b)(vii);

     (ix)   the procedures the Holder must follow to exercise its rights under
            this Section 4.1 and a brief description of such rights;

                                       19
<PAGE>
     (x)    briefly, the conversion rights of the Securities, if any, and that
            the Holder must satisfy the requirements set forth in the Indenture
            in order to convert the Securities;

     (xi)   the procedures for withdrawing a Purchase Notice, including a form
            of notice of withdrawal;

     (xii)  that, unless the Company defaults in making payment of such Purchase
            Price, interest (including any Additional Interest), if any, on
            Securities surrendered for purchase by the Company shall cease to
            accrue on and after the Purchase Date; and

     (xiii) the CUSIP number(s) of the Securities.

            At the Company's request, the Trustee shall give the notice of
            purchase right in the Company's name and at the Company's expense;
            provided, however, that the Company makes such request at least five
            Business Days (unless a shorter period shall be satisfactory to the
            Trustee) prior to the date by which such notice of purchase right
            must be given to the Holders in accordance with this Section 4.1(b);
            provided, further, that the text of the notice of purchase right
            shall be prepared by the Company.

            If any of the Securities is in the form of a Global Security, then
            the Company shall modify such notice to the extent necessary to
            accord with the procedures of the Depositary applicable to the
            purchase of Global Securities.

            Simultaneously with delivering the written notice pursuant to this
            Section 4.1(b), the Company shall publish a notice containing all
            information specified in such written notice in a newspaper of
            general circulation in New York, New York, or publish such
            information on the Company's website, or through such other public
            medium that reasonably could be expected to inform Holders of such
            information.

(c)  A Holder may exercise its rights specified in clause (a) of this Section
     4.1 upon delivery of a written notice (which shall be in substantially the
     form included on the reverse side of the Securities entitled "Option of
     Holder to Elect Purchase" hereto and which may be delivered by letter,
     overnight courier, hand delivery, facsimile transmission or in any other
     written form and, in the case of Global Securities, may be delivered
     electronically or by other means in accordance with the Depositary's
     customary procedures) of the exercise of such rights (a "PURCHASE NOTICE")
     to the Paying Agent at any time from the opening of business on the date
     that is 22 Business Days prior to the relevant Purchase Date until the
     close of business on the second Business Day prior to such Purchase Date.

     The Purchase Notice delivered by a Holder shall state (i) the relevant
     Purchase Date, (ii) if certificated Securities, the certificate number or
     numbers of the Security or Securities which the Holder shall deliver to be
     purchased (if not certificated, the notice must comply with Applicable
     Procedures), (iii) the portion of the Principal Amount of the Security
     which the Holder shall deliver to be purchased, which portion must be
     $1,000 or an integral multiple thereof, and (iv) that such Security shall
     be purchased pursuant to the terms and conditions specified in the
     Securities and this Indenture.

     Delivery of a Security to the Paying Agent by book-entry transfer or
     physical delivery prior to, on or after the applicable Purchase Date
     (together with all necessary endorsements) at the offices of the Paying
     Agent is a condition to receipt by the Holder of the Purchase Price
     therefor; provided, however, that such Purchase Price shall be so paid
     pursuant to this Section 4.1 only if the Security so delivered to the
     Paying Agent shall conform in all respects to the description thereof in
     the related Purchase Notice, as determined by the Company.

     The Company shall purchase from the Holder thereof, pursuant to this
     Section 4.1, a portion of a Security if the Principal Amount of such
     portion is $1,000 or an integral multiple of $1,000. Provisions of this
     Indenture that apply to the purchase of all of a Security pursuant to
     Section 4.1 through Section 4.7 also apply to the purchase of such portion
     of such Security.

     The Paying Agent shall promptly notify the Company of the receipt by it of
     any Purchase Notice or written withdrawal thereof.

     Anything herein to the contrary notwithstanding, in the case of Global
     Securities, any Purchase Notice may be delivered or withdrawn and such
     Securities may be surrendered or delivered for purchase in accordance with
     the Applicable Procedures as in effect from time to time.

                                       20
<PAGE>

Section 4.2. Effect of Purchase Notice; Withdrawal of Purchase Notice.

(a)  Upon receipt by the Paying Agent of the Purchase Notice specified in
     Section 4.1(c), the Holder of the Security in respect of which such
     Purchase Notice was given shall (unless such Purchase Notice is withdrawn
     as specified in the following paragraph) thereafter be entitled to receive
     solely the Purchase Price with respect to such Security. Such Purchase
     Price shall be paid to such Holder, subject to receipt of cash by the
     Paying Agent, promptly following the later of (a) the Purchase Date with
     respect to such Security (provided the conditions in Section 4.1(c) have
     been satisfied) and (b) the time of book-entry transfer or delivery of such
     Security to the Paying Agent by the Holder thereof in the manner required
     by Section 4.1(c). Securities in respect of which a Purchase Notice has
     been given by the Holder thereof may not be converted pursuant to Article
     XII on or after the date of the delivery of such Purchase Notice unless
     such Purchase Notice has first been validly withdrawn as specified in the
     following paragraph.

(b)  A Purchase Notice may be withdrawn by means of a written notice (which may
     be delivered by letter, overnight courier, hand delivery, facsimile
     transmission or in any other written form and, in the case of Global
     Securities, may be delivered electronically or by other means in accordance
     with the Depositary's customary procedures) of withdrawal delivered by the
     Holder to the Paying Agent at any time prior to the close of business on
     the Business Day immediately preceding the Purchase Date, specifying (a)
     the Principal Amount of the Security or portion thereof (which must be a
     Principal Amount of $1,000 or an integral multiple of $1,000 in excess
     thereof) with respect to which such notice of withdrawal is being
     submitted, (b) if certificated Securities have been issued, the certificate
     numbers of the withdrawn Securities, or if not certificated, such notice
     must comply with Applicable Procedures, and (c) the Principal Amount, if
     any, which remains subject to the Purchase Notice. If a Purchase Notice has
     been properly withdrawn pursuant to this Section 4.2(b) prior to the
     Purchase Date, the Company shall not be obligated to purchase those
     Securities so identified in such notice of withdrawal.

Section 4.3. Deposit of Purchase Price.

Prior to 10:00 a.m., New York City time, on the applicable Purchase Date, the
Company shall deposit with the Paying Agent (or if the Company or a Subsidiary
or an Affiliate of either of them is acting as the Paying Agent, shall segregate
and hold in trust as provided in Section 2.4) an amount of cash (in immediately
available funds if deposited on such Business Day) sufficient to pay the
aggregate Purchase Price of all the Securities or portions thereof which are to
be purchased as of such Purchase Date.

If the Paying Agent holds, in accordance with the terms hereof, at 10:00 a.m.,
New York City time, on the applicable Purchase Date, cash sufficient to pay the
Purchase Price of any Securities for which a Purchase Notice has been tendered
and not withdrawn pursuant to Section 4.2(b), then, on such Purchase Date, such
Securities shall cease to be outstanding and interest and Additional Interest,
if any, on such Securities shall cease to accrue, whether or not such Securities
are delivered to the Paying Agent, and the rights of the Holders in respect
thereof shall terminate (other than the right to receive the Purchase Price upon
delivery of such Securities).

The Company shall publicly announce the Principal Amount of Securities purchased
on the applicable Purchase Date on such date or as soon as practicable
thereafter, by publishing a notice containing such information in a newspaper of
general circulation in New York, New York or by publishing such information on
the Company's website, or through such other public medium that reasonably could
be expected to inform Holders of such information.

Section 4.4. Securities Purchased in Part.

Any Certificated Security which is to be purchased only in part shall be
surrendered at the office of the Paying Agent (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 such Holder's attorney duly authorized in writing) and promptly after
the applicable Purchase Date the Company shall execute and the Trustee shall
authenticate and deliver to the Holder of such Security, without charge, a new
Security or Securities, of any authorized denomination or denominations as may
be requested by such Holder, in aggregate principal amount equal to, and in
exchange for, the portion of the Principal Amount of the Security so surrendered
that is not purchased.

                                       21

<PAGE>

Section 4.5. Covenant to Comply With Securities Laws Upon Purchase of
Securities.

When complying with the provisions of Section 4.1 hereof (provided that such
offer or purchase constitutes an "issuer tender offer" for purposes of Rule
13e-4 (which term, as used herein, includes any successor provision thereto)
under the Exchange Act at the time of such offer or purchase), and subject to
any exemptions available under applicable law, the Company shall:

                  (a) if applicable, comply with Rule 13e-4 and Rule 14e-1 (or
         any successor provision) under the Exchange Act;

                  (b) file the related Schedule TO (or any successor schedule,
         form or report) if required under the Exchange Act; and

                  (c) otherwise comply with all United States federal and state
         securities laws so as to permit the rights and obligations under this
         Article IV to be exercised in the time and in the manner specified
         therein.

Section 4.6. Repayment to the Company.

To the extent that the aggregate amount of cash deposited by the Company
pursuant to Section 4.3 exceeds the aggregate Purchase Price of the Securities
or portions thereof which the Company is obligated to purchase as of the
applicable Purchase Date, then, promptly after such Purchase Date, the Paying
Agent shall return any such excess to the Company, together with interest, if
any, thereon.

Section 4.7. No Purchase Upon Event of Default.

There shall be no purchase of any Securities pursuant to this Article IV if
there has occurred (prior to, on or after, as the case may be, the giving by
each of the Holders of such Securities of the required Purchase Notice but, in
any event, prior to the applicable Purchase Date) and is continuing, as of such
Purchase Date, an Event of Default (other than a default in the payment of the
Purchase Price with respect to such Securities). The Paying Agent shall promptly
return to the respective Holders thereof any Securities (a) with respect to
which a Purchase Notice has been delivered in compliance with this Indenture, or
(b) held by it during the continuance of an Event of Default (other than a
default in the payment of the Purchase Price with respect to such Securities),
in which case, upon such return, the Purchase Notice with respect thereto shall
be deemed to have been withdrawn.

                                   ARTICLE V

                        PURCHASE AT THE OPTION OF HOLDERS
                             UPON A DESIGNATED EVENT

Section 5.1. Designated Event Put.

(a)  In the event that a Designated Event shall occur at any time prior to
     December 15, 2023, each Holder shall have the right, at the Holder's
     option, but subject to the provisions of this Section 5.1, to require the
     Company to purchase, and upon the exercise of such right, the Company shall
     purchase, all of such Holder's Securities not theretofore called for
     redemption, or any portion of the Principal Amount thereof that is equal to
     $1,000 or an integral multiple thereof, as directed by such Holder pursuant
     to this Section 5.1, on the date designated by the Company (the "DESIGNATED
     EVENT PURCHASE DATE") that is a Business Day no later than 35 Business Days
     after the date of notice pursuant to Section 5.1(b) of the occurrence of a
     Designated Event (subject to extension to comply with applicable law). The
     Company shall be required to purchase such Securities at a purchase price
     in cash equal to 100% of the Principal Amount plus any accrued and unpaid
     interest (including any Additional Interest) to, but excluding, the
     Designated Event Purchase Date (the "DESIGNATED EVENT PURCHASE PRICE"). In
     the event that a Designated Event Purchase Date is a date that is after any
     Regular Record Date but on or before the corresponding Interest Payment
     Date, the Company shall be required to pay accrued and unpaid interest and
     Additional Interest, if any, to the holder of the repurchased Security and
     not the Holder on the Regular Record Date.

                                       22
<PAGE>

(b)  No later than 20 calendar days after the occurrence of a Designated Event,
     the Company shall mail a written notice of the Designated Event by first
     class mail to the Trustee (and the Paying Agent if the Trustee is not then
     acting as Paying Agent) and to each Holder at its address shown in the
     Register of the Registrar, and to beneficial owners as required by
     applicable law. The notice shall include a form of Designated Event
     Purchase Notice to be completed by the Holder and shall briefly state, as
     applicable:

     (i)    the date of such Designated Event and, briefly, the events causing
            such Designated Event;

     (ii)   the date by which the Designated Event Purchase Notice must be
            delivered to the Paying Agent in order for a Holder to exercise the
            purchase right pursuant to this Section 5.1;

     (iii)  the Designated Event Purchase Date;

     (iv)   the Designated Event Purchase Price;

     (v)    the name and address of the Paying Agent and Conversion Agent;

     (vi)   the Conversion Rate and any adjustments thereto;

     (vii)  that the Securities as to which a Designated Event Purchase Notice
            has been given may be converted into Common Stock pursuant to
            Article XII of this Indenture only if the Designated Event Purchase
            Notice has been withdrawn in accordance with the terms of this
            Indenture;

     (viii) that the Securities must be surrendered to the Paying Agent to
            collect payment;

     (ix)   that the Designated Event Purchase Price for any Security as to
            which a Designated Event Purchase Notice has been duly given and not
            withdrawn shall be paid promptly following the later of the
            Designated Event Purchase Date and the time of surrender of such
            Security as described in Section 5.1(b)(viii);

     (x)    the procedures the Holder must follow to exercise rights under this
            Section 5.1 and a brief description of such rights;

     (xi)   briefly, the conversion rights of the Securities, and that the
            Holder must satisfy the requirements set forth in the Indenture in
            order to convert the Securities;

     (xii)  the procedures for withdrawing a Designated Event Purchase Notice,
            including a form of notice of withdrawal;

     (xiii) that, unless the Company defaults in making payment of such
            Designated Event Purchase Price, interest (including any Additional
            Interest), if any, on Securities surrendered for purchase by the
            Company shall cease to accrue on and after the Designated Event
            Purchase Date; and

     (xiv)  the CUSIP number(s) of the Securities.

            At the Company's request, the Trustee shall give the notice of
     purchase right in the Company's name and at the Company's expense;
     provided, however, that the Company makes such request at least five
     Business Days (unless a shorter period shall be satisfactory to the
     Trustee) prior to the date by which such notice of purchase right must be
     given to the Holders in accordance with this Section 5.1(b); provided,
     further, that the text of the notice of purchase right shall be prepared by
     the Company.

            If any of the Securities is in the form of a Global Security, then
     the Company shall modify such notice to the extent necessary to accord with
     the procedures of the Depositary applicable to the purchase of Global
     Securities.

                                       23
<PAGE>
     Simultaneously with delivering the written notice pursuant to this Section
     5.1(b), the Company shall publish a notice containing all information
     specified in such written notice in a newspaper of general circulation in
     New York, New York or publish such information on the Company's website, or
     through such other public medium that reasonably could be expected to
     inform Holders of such information.

(c)  A Holder may exercise its rights specified in clause (a) of this Section
     5.1 upon delivery of a written notice (which shall be in substantially the
     form included on the reverse side of the Securities entitled "Option of
     Holder to Elect Purchase" hereto and which may be delivered by letter,
     overnight courier, hand delivery, facsimile transmission or in any other
     written form and, in the case of Global Securities, may be delivered
     electronically or by other means in accordance with the Depositary's
     customary procedures) of the exercise of such rights (a "DESIGNATED EVENT
     PURCHASE NOTICE") to the Paying Agent at any time on or before the 20th
     Business Day after the date of the Company's notice of the Designated Event
     (subject to extension to comply with applicable law).

                  The Designated Event Purchase Notice delivered by a Holder
     shall state (i) the Designated Event Purchase Date, (ii) if certificated
     Securities, the certificate number or numbers of the Security or Securities
     which the Holder shall deliver to be purchased (if not certificated, the
     notice must comply with Applicable Procedures), (iii) the portion of the
     Principal Amount of the Security which the Holder shall deliver to be
     purchased, which portion must be $1,000 or an integral multiple thereof,
     and (iv) that such Security shall be purchased pursuant to the terms and
     conditions specified in the Securities and this Indenture.

                  Delivery of a Security (together with all necessary
     endorsements) to the Paying Agent by book-entry transfer or physical
     delivery prior to, on or after the Designated Event Purchase Date at the
     offices of the Paying Agent is a condition to receipt by the Holder of the
     Designated Event Purchase Price therefor; provided, however, that such
     Designated Event Purchase Price shall be so paid pursuant to this Section
     5.1 only if the Security so delivered to the Paying Agent shall conform in
     all respects to the description thereof in the related Designated Event
     Purchase Notice, as determined by the Company.

                  The Company shall purchase from the Holder thereof, pursuant
     to this Section 5.1, a portion of a Security if the Principal Amount of
     such portion is $1,000 or an integral multiple of $1,000. Provisions of the
     Indenture that apply to the purchase of all of a Security pursuant to
     Section 5.1 through Section 5.6 also apply to the purchase of such portion
     of such Security.

                  A Paying Agent shall promptly notify the Company of the
     receipt by it of any Designated Event Purchase Notice or written withdrawal
     thereof.

                  Anything herein to the contrary notwithstanding, in the case
     of Global Securities, any Designated Event Purchase Notice may be delivered
     or withdrawn and such Securities may be surrendered or delivered for
     purchase in accordance with the Applicable Procedures as in effect from
     time to time.

Section 5.2. Effect of Designated Event Purchase Notice.

(a)  Upon receipt by the Paying Agent of the Designated Event Purchase Notice
     specified in Section 5.1(c), the Holder of the Security in respect of which
     such Designated Event Purchase Notice was given shall (unless such
     Designated Event Purchase Notice is withdrawn as specified in the following
     paragraph) thereafter be entitled to receive the Designated Event Purchase
     Price with respect to such Security. Such Designated Event Purchase Price
     shall be paid to such Holder, subject to receipt of cash by the Paying
     Agent, promptly following the later of (a) the Designated Event Purchase
     Date with respect to such Security (provided the conditions in Section
     5.1(c) have been satisfied) and (b) the time of book-entry transfer or
     delivery of such Security to the Paying Agent by the Holder thereof in the
     manner required by Section 5.1(c). Securities in respect of which a
     Designated Event Purchase Notice has been given by the Holder thereof may
     not be converted pursuant to Article XII on or after the date of the
     delivery of such Designated Event Purchase Notice unless such Designated
     Event Purchase Notice has first been validly withdrawn as specified in the
     following paragraph.

(b)  A Designated Event Purchase Notice may be withdrawn by means of a written
     notice (which may be delivered by letter, overnight courier, hand delivery,
     facsimile transmission or in any other written form and, in the case of
     Global Securities, may be delivered electronically or by other means in
     accordance with the Depositary's customary procedures) of withdrawal
     delivered by the Holder to the Paying Agent at any time prior to the close
     of business on the Business Day immediately preceding the Designated Event
     Purchase Date, specifying (a) the Principal Amount of the Security or
     portion thereof (which must be a Principal Amount of $1,000 or an integral

                                       24
<PAGE>

     multiple of $1,000 in excess thereof) with respect to which such notice of
     withdrawal is being submitted, (b) if certificated Securities have been
     issued, the certificate numbers of the withdrawn Securities, or if not
     certificated, such notice must comply with Applicable Procedures, and (c)
     the Principal Amount, if any, which remains subject to the Designated Event
     Purchase Notice. If a Designated Event Purchase Notice has been properly
     withdrawn pursuant to this Section 5.2(b) prior to the Designated Event
     Purchase Date, the Company shall not be obligated to purchase those
     Securities so identified in such notice of withdrawal.

Section 5.3. Deposit of Designated Event Purchase Price.

Prior to 10:00 a.m., New York City time, on the applicable the Designated Event
Purchase Date or the Business Day following the Designated Event Purchase Date,
the Company shall deposit with the Paying Agent (or if the Company or a
Subsidiary or an Affiliate of either of them is acting as the Paying Agent,
shall segregate and hold in trust as provided in Section 2.4) an amount of cash
(in immediately available funds if deposited on such Business Day) sufficient to
pay the aggregate Designated Event Purchase Price of all the Securities or
portions thereof which are to be purchased as of such Designated Event Purchase
Date.

If the Paying Agent holds, in accordance with the terms hereof, at 10:00 a.m.,
New York City time, on the applicable Designated Event Purchase Date, cash
sufficient to pay the Designated Event Purchase Price of any Securities for
which a Designated Event Purchase Notice has been tendered and not withdrawn
pursuant to Section 5.2(b), then, on such Designated Event Purchase Date, such
Securities shall cease to be outstanding and interest and Additional Interest,
if any, on such Securities shall cease to accrue, whether or not such Securities
are delivered to the Paying Agent, and the rights of the Holders in respect
thereof shall terminate (other than the right to receive the Designated Event
Purchase Price upon delivery of such Securities).

The Company shall publicly announce the Principal Amount of Securities purchased
as a result of such Designated Event on or as soon as practicable after the
Designated Event Purchase Date by publishing a notice containing such
information in a newspaper of general circulation in New York, New York or by
publishing such information on the Company's website, or through such other
public medium that reasonably could be expected to inform Holders of such
information.

Section 5.4. Securities Purchased in Part.

Any Certificated Security that is to be purchased only in part shall be
surrendered at the office of the Paying Agent (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 such Holder's attorney duly authorized in writing) and promptly after
the Designated Event Purchase Date the Company shall execute and the Trustee
shall authenticate and deliver to the Holder of such Security, without charge, a
new Security or Securities, of any authorized denomination or denominations as
may be requested by such Holder, in aggregate Principal Amount equal to, and in
exchange for, the portion of the Principal Amount of the Security so surrendered
that is not purchased.

Section 5.5. Covenant to Comply With Securities Laws Upon Purchase of
Securities.

When complying with the provisions of Section 5.1 hereof (provided that such
offer or purchase constitutes an "issuer tender offer" for purposes of Rule
13e-4 (which term, as used herein, includes any successor provision thereto)
under the Exchange Act at the time of such offer or purchase), and subject to
any exemptions available under applicable law, the Company shall:

                  (a)      if applicable, comply with Rule 13e-4 and Rule 14e-1
         (or any successor provision) under the Exchange Act;

                  (b)      file the related Schedule TO (or any successor
         schedule, form or report) if required under the Exchange Act; and

                  (c)      otherwise comply with all United States federal and
         state securities laws so as to permit the rights and obligations under
         this Article V to be exercised in the time and in the manner specified
         therein.

                                       25
<PAGE>

Section 5.6. Repayment to the Company.

To the extent that the aggregate amount of cash deposited by the Company
pursuant to Section 5.3 exceeds the aggregate Designated Event Purchase Price of
the Securities or portions thereof which the Company is obligated to purchase as
of the Designated Event Purchase Date then, promptly after the Designated Event
Purchase Date, the Paying Agent shall return any such excess to the Company
together with interest, if any, thereon.

                                   ARTICLE VI

                                    COVENANTS

Section 6.1. Payment of Securities.

The Company shall pay interest on the Securities as provided in the Securities.
The Company shall promptly make all payments in respect of the Securities on the
dates and in the manner provided in the Securities or pursuant to this
Indenture. Principal amount, Redemption Price, Purchase Price and Designated
Event Purchase Price and accrued and unpaid interest and Additional Interest, if
any, shall be considered paid on the applicable date due if by 10:00 a.m., New
York City time, on such date the Paying Agent holds, in accordance with this
Indenture, cash or securities, if permitted hereunder, sufficient to pay all
such amounts then due. The Company shall, to the fullest extent permitted by
law, pay interest on overdue principal and overdue installments of interest and
Additional Interest, if any, at the rate borne by the Securities per annum. All
references in this Indenture or the Securities to interest shall be deemed to
include Additional Interest, if any, payable pursuant to the Registration Rights
Agreement.

Payment of the principal of and interest and Additional Interest, if any, on the
Securities shall be 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
or in Applicable Stock, as the case may be.

Subject to Section 3.1, Section 4.1 and and Section 5.1, the Company shall pay
interest and Additional Interest, if any, on the Securities to the Person in
whose name the Securities are registered at the close of business on the Regular
Record Date next preceding the corresponding Interest Payment Date. Any such
interest and Additional Interest, if any, not so punctually paid or duly
provided for shall forthwith cease to be payable to the Holder on such Regular
Record Date and may be paid (a) to the Person in whose name the Securities are
registered at the close of business on a Special Record Date for the payment of
such defaulted interest and Additional Interest, if any, to be fixed by the
Trustee, notice whereof shall be given to the Holders not less than 10 calendar
days prior to such Special Record Date or (b) at any time in any other lawful
manner not inconsistent with the requirements of any securities exchange on
which the Securities may be listed, and upon such notice as may be required by
such exchange.

The Holder must surrender the Securities to the Paying Agent to collect payment
of principal. Payment of interest and Additional Interest, if any, on
Certificated Securities in the aggregate principal amount of $5,000,000 or less
shall be made by check mailed to the address of the Person entitled thereto as
such address appears in the Register, and payment of interest and Additional
Interest, if any, on Certificated Securities in aggregate principal amount in
excess of $5,000,000 shall be made by wire transfer in immediately available
funds at the election of such Holder. Notwithstanding the foregoing, so long as
the Securities are registered in the name of a Depositary or its nominee, all
payments with respect to the Securities shall be made by wire transfer of
immediately available funds to the account of the Depositary or its nominee.

Section 6.2. SEC and Other Reports to the Trustee.

(a)  The Company shall ensure delivery to the Trustee within 15 calendar days
     after it files such annual and quarterly reports, information, documents
     and other reports with the SEC, copies of its annual report and of the
     information, documents and other reports (or copies of such portions of any
     of the foregoing as the SEC may by rules and regulations prescribe) which
     the Company is required to file with the SEC pursuant to Section 13 or
     15(d) of the Exchange Act in accordance with TIA Section 314(a). In the
     event the Company is at any time no longer subject to the reporting
     requirements of Section 13 or 15(d) of the Exchange Act, it shall continue
     to provide the Trustee with reports containing substantially the same
     information as would have been required to be filed with the SEC had the
     Company continued to have been subject to such reporting requirements. In
     such

                                       26
<PAGE>

     event, such reports shall be provided at the times the Company would have
     been required to provide reports had it continued to have been subject
     to such reporting requirements. The Company also shall comply with the
     other provisions of TIA Section 314(a). Delivery of such reports,
     information and documents to the Trustee is for informational purposes only
     and the Trustee's receipt of such shall not constitute constructive notice
     of any information contained therein or determinable from information
     contained therein, including the Company's compliance with any of its
     covenants hereunder (as to which the Trustee is entitled to rely
     conclusively on Officers' Certificates). The Trustee shall have no duty or
     responsibility to review such reports, information or documents.

(b)  The Company intends to file the reports referred to in paragraph (a) above
     in this Section 6.2 hereof with the SEC in electronic form pursuant to
     Regulation S-T of the SEC using the SEC's Electronic Data Gathering,
     Analysis and Retrieval ("EDGAR") system. The Company shall notify the
     Trustee in the manner prescribed herein of each such filing. The Trustee is
     hereby authorized and directed to access the EDGAR system for purposes of
     retrieving the reports so filed. Compliance with the foregoing shall
     constitute delivery by the Company of such reports to the Trustee in
     compliance with the provisions of TIA Section 314(a). The Trustee shall
     have no duty to search for or obtain any electronic or other filings that
     the Company makes with the SEC, regardless of whether such filings are
     periodic, supplemental or otherwise. Delivery of the reports, information
     and documents to the Trustee pursuant to this Section 6.2(b) shall be
     solely for the purposes of compliance with this Section 6.2(b) and with TIA
     Section 314(a). The Trustee's receipt of such reports, information and
     documents shall not constitute notice to it of the consent thereof or of
     any matter determinable from the content thereof, including the Company's
     compliance with any of its covenants hereunder, as to which the Trustee is
     entitled to rely upon Officers' Certificates.

Section 6.3. Compliance Certificate.

The Company shall deliver to the Trustee within 120 calendar days after the end
of each fiscal year of the Company an Officers' Certificate, stating whether or
not to the knowledge of the signers thereof, the Company is in compliance with
all conditions and covenants under this Indenture.

Section 6.4. Further Instruments and Acts.

Upon request of the Trustee, or as otherwise necessary, the Company shall
execute and deliver such further instruments and do such further acts as may be
reasonably necessary or proper to carry out more effectively the purposes of
this Indenture.

Section 6.5. Maintenance of Office or Agency of the Trustee, Registrar, Paying
Agent and Conversion Agent.

The Company shall maintain in the Borough of Manhattan, New York, New York, an
office or agency of the Trustee, Registrar, Paying Agent and Conversion Agent
where Securities may be presented or surrendered for payment, where Securities
may be surrendered for registration of transfer, exchange, redemption,
repurchase or conversion and where notices and demands to or upon the Company in
respect of the Securities and this Indenture may be served. The office of
Wilmington Trust Company located in New York City at 520 Madison Avenue, 33rd
Floor, New York, NY 10022, shall initially be such office or agency for all of
the aforesaid purposes. The Company shall give prompt written notice to the
Trustee of the location, and of any change in the location, of any such office
or agency (other than a change in the location of the office of the Trustee). If
at any time the Company shall fail to maintain any such required office or
agency or shall fail to furnish the Trustee with the address thereof, such
presentations, surrenders, notices and demands may be made or served at the
address of the Trustee set forth in Section 13.2.

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

                                       27
<PAGE>

Section 6.6. Delivery of Information Required Under Rule 144A.

At any time when the Company is not subject to Section 13 or 15(d) of the
Exchange Act, upon the request of a Holder or any beneficial owner of Securities
or holder or beneficial owner of Common Stock issued upon conversion thereof,
the Company shall promptly furnish or cause to be furnished the information
required pursuant to Rule 144A(d)(4) under the Securities Act to such Holder or
any beneficial owner of Securities or holder or beneficial owner of Common
Stock, or to a prospective purchaser of any such security designated by any such
holder, as the case may be, to the extent required to permit compliance by such
Holder or holder with Rule 144A under the Securities Act in connection with the
resale of any such security. Whether a person is a beneficial owner shall be
determined by the Company to the Company's reasonable satisfaction.

Section 6.7. Waiver of Stay, Extension or Usury Laws.

The Company covenants (to the extent that it may lawfully do so) that it shall
not at any time insist upon, or plead, or in any manner whatsoever claim or take
the benefit or advantage of, any stay or extension law or any usury or other law
wherever enacted, now or at any time hereafter in force, which would prohibit or
forgive the Company from paying all or any portion of the principal amount,
Redemption Price, Purchase Price or Designated Event Purchase Price in respect
of Securities, or any interest and Additional Interest, if any, on such amounts,
as contemplated herein, or 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 shall not hinder, delay or impede the execution of any power herein
granted to the Trustee, but shall suffer and permit the execution of every such
power as though no such law had been enacted.

Section 6.8. Statement by Officers as to Default.

The Company shall deliver to the Trustee, as soon as practicable and in any
event within five Business Days after the Company becomes aware of the
occurrence of any Default or Event of Default, an Officers' Certificate setting
forth the details of such Default or Event of Default and the action which the
Company proposes to take with respect thereto.

                                  ARTICLE VII

                              SUCCESSOR CORPORATION

Section 7.1. When Company May Merge or Transfer Assets.

The Company shall not consolidate with or merge with or into any other person or
convey, transfer, sell, lease or otherwise dispose of all or substantially all
of its properties and assets to any person, unless:

                  (a)      either (i) the Company shall be the continuing
         corporation or (ii) the Person (if other than the Company) formed by
         such consolidation or into which the Company is merged or the Person
         which acquires by conveyance, transfer, sale, lease or other
         disposition all or substantially all of the properties and assets of
         the Company substantially as an entirety (1) shall be organized and
         validly existing under the laws of the United States or any State
         thereof or the District of Columbia and (2) shall expressly assume, by
         an indenture supplemental hereto, executed and delivered to the
         Trustee, in form reasonably satisfactory to the Trustee, all of the
         obligations of the Company under the Securities and this Indenture;

                  (b)      immediately after giving effect to such transaction,
         no Default shall have occurred and be continuing; and

                  (c)      the Company shall have delivered to the Trustee an
         Officers' Certificate and an Opinion of Counsel, each stating that such
         consolidation, merger, conveyance, transfer, sale, lease or other
         disposition and, if a supplemental indenture is required in connection
         with such transaction, such supplemental indenture, comply with this
         Article VII and that all conditions precedent herein provided for
         relating to such transaction have been satisfied.

                                       28
<PAGE>

For purposes of the foregoing, the transfer (by lease, assignment, sale or
otherwise) of the properties and assets of one or more Subsidiaries, which, if
such assets were owned by the Company, together with the assets of all of the
other Subsidiaries of the Company, would constitute all or substantially all of
the properties and assets of the Company, shall be deemed to be the transfer of
all or substantially all of the properties and assets of the Company unless such
transfer is to the Company or another Subsidiary. The successor Person formed by
such consolidation or into which the Company is merged or the successor Person
to which such conveyance, transfer, sale, lease or other disposition is made
shall succeed to, and be substituted for, and may exercise every right and power
of, the Company under this Indenture with the same effect as if such successor
had been named as the Company herein; and thereafter, except in the case of a
conveyance, transfer, sale, lease or other disposition and any obligations the
Company may have under a supplemental indenture, the Company shall be discharged
from all obligations and covenants under this Indenture and the Securities.
Subject to Section 11.6, the Company, the Trustee and the successor Person shall
enter into a supplemental indenture to evidence the succession and substitution
of such successor Person and such discharge and release of the Company.

                                  ARTICLE VIII

                              DEFAULTS AND REMEDIES

Section 8.1. Events of Default.

So long as any Securities are outstanding, each of the following shall be an
"EVENT OF DEFAULT":

                  (a)      the Company defaults in the payment of the principal
         amount of any Security when the same becomes due and payable as therein
         provided or as provided in this Indenture, whether at Stated Maturity
         or by declaration of acceleration;

                  (b)      the Company defaults in the payment of any accrued
         and unpaid interest on any Security and Additional Interest, if any, in
         each case, when due and payable, and such default shall continue for a
         period of 30 days;

                  (c)      the Company fails to convert any portion of the
         principal amount of any Security following the exercise by the Holder
         of the right to convert such Security into Common Stock pursuant to and
         in accordance with Article XII unless the Company elects pursuant to
         Section 12.13, to deliver, in lieu of Common Stock, cash or a
         combination of cash and Common Stock, and fails to deliver such cash or
         such combination of cash and Common Stock;

                  (d)      the Company defaults in its obligation to redeem any
         Security, or any portion thereof, called for redemption by the Company
         pursuant to and in accordance with Article III and;

                  (e)      the Company defaults in its obligation to purchase
         any Security, or any portion thereof, upon the exercise by the Holder
         of such Holder's right to require the Company to purchase such
         Securities pursuant to and in accordance with Article IV or Article V;

                  (f)      the Company defaults in its obligation to provide
         notice in the event of a Designated Event in accordance with Section
         5.1(b);

                  (g)      there shall be a default in the performance, or
         breach, of any covenant or agreement of the Company under this
         Indenture (other than a default in the performance or breach of a
         covenant or agreement which is specifically dealt with in clause (a),
         (b), (d) or (e)) and such default or breach shall continue for a period
         of 60 days after written notice has been given, by certified mail, (1)
         to the Company by the Trustee or (2) to the Company and the Trustee by
         the Holders of at least 25% in aggregate principal amount of the
         Securities then outstanding;

                                       29
<PAGE>
                  (h)      there shall have occurred a default under any credit
         agreement, mortgage, indenture or instrument under which there may be
         issued or by which there may be secured or evidenced any Indebtedness
         of the Company or any of its Subsidiaries whether such Indebtedness now
         exists, or is created after the date of this Indenture, which default
         (i) involves the failure to pay principal of or any premium or interest
         on such Indebtedness in an amount in excess of $7.5 million when such
         Indebtedness becomes due and payable at the stated maturity thereof,
         and such default shall continue after any applicable grace period or
         (ii) results in the acceleration of such Indebtedness unpaid prior to
         the stated maturity thereof (without such acceleration being rescinded
         or annulled) and, in the case of (ii), the principal amount of such
         Indebtedness, together with the principal amount of any other
         Indebtedness so unpaid at its stated maturity or the stated maturity of
         which has been so accelerated, aggregates $10,000,000 or more;

                  (i)      there shall be a failure by the Company or any of its
         Subsidiaries to pay final judgments not covered by insurance
         aggregating in excess of $7,500,000, which judgments are not paid,
         discharged or stayed for a period of 60 calendar days; and

                  (j)      the Company or any Designated Subsidiary, or any
         group of two or more Subsidiaries that, taken as a whole, would
         constitute a Designated Subsidiary, pursuant to or under or within the
         meaning of any Bankruptcy Law:

          (i)   commences a voluntary case or proceeding;

          (ii)  consents to the entry of any order for relief against it in an
                involuntary case or proceeding or the commencement of any case
                against it;

          (iii) consents to the appointment of a Custodian of it or for any
                substantial part of its property;

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

          (v)   files a petition in bankruptcy or answer or consent seeking
                reorganization or relief; or

          (vi)  consents to the filing of such petition or the appointment of or
                taking possession by a Custodian; or

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

          (i)   is for relief against the Company or any Designated Subsidiary
                in an involuntary case or proceeding, or adjudicates the Company
                or any Designated Subsidiary insolvent or bankrupt;

          (ii)  appoints a Custodian of the Company or any Designated Subsidiary
                or for any substantial part of the property of either; or

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

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

Section 8.2. Acceleration.

If an Event of Default (other than an Event of Default specified in Section
8.1(j) or Section 8.1(k) with respect to the Company) occurs and is continuing
(including an Event of Default specified in Section 8.1(j) or Section 8.1(k)
with respect to one or more Designated Subsidiaries), the Trustee by notice to
the Company, or the Holders of at least 25% in aggregate principal amount of the
Securities at the time outstanding by notice to the Company and the Trustee, may
declare the principal amount plus accrued and unpaid interest and Additional
Interest, if any, on all the Securities to be immediately due and payable.

                                       30
<PAGE>

Upon such a declaration, such accelerated amount shall be due and payable
immediately.

If an Event of Default specified in Section 8.1(j) or Section 8.1(k) occurs with
respect to the Company and is continuing, the principal amount plus accrued and
unpaid interest and Additional Interest, if any, on all the Securities shall
become and be immediately due and payable without any declaration or other act
on the part of the Trustee or any Holders.

The Holders of a majority in aggregate principal amount of the Securities at the
time outstanding, by notice to the Trustee (and without notice to any other
Holder) may rescind an acceleration and its consequences if the rescission would
not conflict with any judgment or decree and if all existing Events of Default
have been cured or waived except nonpayment of the principal amount plus accrued
and unpaid interest and Additional Interest, if any, that have become due solely
as a result of acceleration and if all amounts due to the Trustee under Section
9.7 have been paid. No such rescission shall affect any subsequent Default or
impair any right consequent thereto.

Section 8.3. Other Remedies.

If an Event of Default occurs and is continuing, the Trustee may, but shall not
be obligated to, pursue any available remedy to collect the payment of the
principal amount plus accrued and unpaid interest and Additional Interest, if
any, on the Securities or to enforce the performance of any provision of the
Securities or this Indenture.

The Trustee may maintain a proceeding even if the Trustee does not possess any
of the Securities or does not produce any of the Securities in the proceeding. A
delay or omission by the Trustee or any Holder in exercising any right or remedy
accruing upon an Event of Default shall not impair the right or remedy or
constitute a waiver of, or acquiescence in, the Event of Default. No remedy is
exclusive of any other remedy. All available remedies are cumulative.

Section 8.4. Waiver of Past Defaults.

Subject to Section 8.7 and Section 11.2, the Holders of a majority in aggregate
principal amount of the Securities at the time outstanding, by notice to the
Trustee (and without notice to any other Holder), may waive an existing Default
and its consequences except:

                  (a)      an Event of Default described in Section 8.1(a),
         Section 8.1(b), Section 8.1(d) or Section 8.1(e);

                  (b)      a Default which constitutes a failure to convert any
         Security in accordance with the terms of Article XII; or

                  (c)      a Default in respect of any provision of this
         Indenture or the Securities, which, under Section 11.2, cannot be
         amended or modified without the consent of each Holder affected
         thereby.

When a Default is waived, it is deemed cured, but no such waiver shall extend to
any subsequent or other Default or impair any consequent right. This Section 8.4
shall be in lieu of Section 316(a)1(B) of the TIA and such Section 316(a)1(B) is
hereby expressly excluded from this Indenture, as permitted by the TIA.

Section 8.5. Control by Majority.

The Holders of a majority in aggregate principal amount of the Securities at the
time outstanding may direct the time, method and place of conducting any
proceeding for any remedy available to the Trustee or of exercising any trust or
power conferred on the Trustee. However, the Trustee may refuse to follow any
direction that conflicts with law or this Indenture or that the Trustee
determines in good faith is prejudicial to the rights of other Holders or would
involve the Trustee in personal liability unless the Trustee is provided
indemnity satisfactory to it. This Section 8.5 shall be in lieu of Section
316(a)1(A) of the TIA and such Section 316(a)1(A) is hereby expressly excluded
from this Indenture, as permitted by the TIA.

Section 8.6. Limitation on Suits.

A Holder may not pursue any remedy with respect to this Indenture or the
Securities unless:

                  (a)      the Holder gives to the Trustee written notice
         stating that an Event of Default is continuing;

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<PAGE>

                  (b)      the Holders of at least 25% in aggregate principal
         amount of the Securities at the time outstanding make a written request
         to the Trustee to pursue the remedy;

                  (c)      such Holder or Holders provide to the Trustee
         security or indemnity satisfactory to the Trustee against any loss,
         liability or expense;

                  (d)      the Trustee does not comply with the request within
         60 days after receipt of such notice, request and offer of security or
         indemnity; and

                  (e)      the Holders of a majority in aggregate principal
         amount of the Securities at the time outstanding do not give the
         Trustee a direction inconsistent with the request during such 60-day
         period.

A Holder may not use this Indenture to prejudice the rights of any other Holder
or to obtain a preference or priority over any other Holder.

Section 8.7. Rights of Holders to Receive Payment or to Convert.

Notwithstanding any other provision of this Indenture, the right of any Holder
to receive payment of the principal amount, Redemption Price, Purchase Price,
Designated Event Purchase Price or interest and Additional Interest, if any, in
respect of the Securities held by such Holder, on or after the respective due
dates expressed in the Securities and in this Indenture, and to convert such
Securities in accordance with Article XII, or to bring suit for the enforcement
of any such payment on or after such respective dates or the right to convert,
is absolute and unconditional and shall not be impaired or affected adversely
without the consent of such Holder.

Section 8.8. Collection Suit by Trustee.

If an Event of Default described in Section 8.1(a), Section 8.1(b), Section
8.1(d) or Section 8.1(e) occurs and is continuing, the Trustee may recover
judgment in its own name and as trustee of an express trust against the Company
or another obligor on the Securities for the whole amount owing with respect to
the Securities and the amounts provided for in Section 9.7.

Section 8.9. Trustee May File Proofs of Claim.

In case of the pendency of any receivership, insolvency, liquidation,
bankruptcy, reorganization, arrangement, adjustment, composition or other
judicial proceeding relative to the Company or any other obligor upon the
Securities or the property of the Company or of such other obligor or their
creditors, the Trustee (irrespective of whether the principal amount, Redemption
Price, Purchase Price, Designated Event Purchase Price or interest and
Additional Interest, if any, in respect of the Securities shall then be due and
payable as therein expressed or by declaration or otherwise and irrespective of
whether the Trustee shall have made any demand on the Company for the payment of
any such amount) shall be entitled and empowered, by intervention in such
proceeding or otherwise:

                  (a)      to file and prove a claim for the whole amount of the
         principal amount, Redemption Price, Purchase Price, Designated Event
         Purchase Price, or interest and Additional Interest, if any, and to
         file such other papers or documents as may be necessary or advisable in
         order to have the claims of the Trustee (including any claim for the
         reasonable compensation, expenses, disbursements and advances of the
         Trustee, its agents and counsel or any other amounts due the Trustee
         under Section 9.7) and of the Holders allowed in such judicial
         proceeding, and

                  (b)      to collect and receive any moneys or other property
         payable or deliverable on any such claims and to distribute the same;

and any custodian, receiver, assignee, trustee, liquidator, sequestrator or
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 the
Trustee any amount due it for the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel, and any other
amounts due the Trustee under Section 9.7.

                                       32
<PAGE>

Nothing contained herein 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.

Section 8.10. Priorities.

If the Trustee collects any money pursuant to this Article VIII, it shall pay
out the money in the following order:

                  FIRST: to the Trustee for amounts due under Section 9.7;

                  SECOND: to Holders for amounts due and unpaid on the
         Securities for the principal amount, Redemption Price, Purchase Price,
         Designated Event Purchase Price or interest and Additional Interest, if
         any, as the case may be, ratably, without preference or priority of any
         kind, according to such amounts due and payable on the Securities; and

                  THIRD:  the balance, if any, to the Company.

The Trustee may fix a record date and payment date for any payment to Holders
pursuant to this Section 8.10. At least 10 calendar days prior to such record
date, the Trustee shall mail to each Holder and the Company a notice that states
the record date, the payment date and the amount to be paid.

Section 8.11. Undertaking for Costs.

In any suit for the enforcement of any right or remedy under this Indenture or
in any suit against the Trustee for any action taken or omitted by it as
Trustee, a court in its discretion may require the filing by any party litigant
(other than the Trustee) in the suit of an undertaking to pay the costs of the
suit, and the court in its discretion may assess reasonable costs, including
reasonable attorneys' fees and expenses, against any party litigant in the suit,
having due regard to the merits and good faith of the claims or defenses made by
the party litigant. This Section 8.11 does not apply to a suit by the Trustee, a
suit by a Holder pursuant to Section 8.7 or a suit by Holders of more than 10%
in aggregate principal amount of the Securities at the time outstanding. This
Section 8.11 shall be in lieu of Section 315(e) of the TIA and such Section
315(e) is hereby expressly excluded from this Indenture, as permitted by the
TIA.

                                   ARTICLE IX

                                     TRUSTEE

Section 9.1. Duties of Trustee.

(a)  If an Event of Default has occurred and is continuing, the Trustee shall
     exercise the rights and powers vested in it by this Indenture and use the
     same degree of care and skill in its exercise of those rights and powers as
     a prudent person would exercise or use under the circumstances in the
     conduct of such person's own affairs.

(b)  Except during the continuance of an Event of Default:

     (i)  the Trustee need perform only those duties that are specifically set
          forth in this Indenture and no others; and

     (ii) in the absence of bad faith on its part, the Trustee may conclusively
          rely, as to the truth of the statements and the correctness of the
          opinions expressed therein, upon certificates or opinions furnished to
          the Trustee and conforming to the requirements of this Indenture, but
          in the case of any such certificates or opinions which by any
          provision hereof are specifically required to be furnished to the
          Trustee, the Trustee shall examine the certificates and opinions to
          determine whether or not they conform to the requirements of this
          Indenture, but need not confirm or investigate the accuracy of
          mathematical calculations or other facts stated therein.

This Section 9.1(b) shall be in lieu of Section 315(a) of the TIA and such
Section 315(a) is hereby expressly excluded from this Indenture, as permitted by
the TIA.

(c)  The Trustee may not be relieved from liability for its own negligent
     action, its own negligent failure to act or its own willful misconduct,
     except that:

                                       33
<PAGE>
     (i)  this clause (c) does not limit the effect of clause (b) of this
          Section 9.1;

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

     (iii) the Trustee shall not be liable with respect to any action it takes
          or omits to take in good faith in accordance with a direction received
          by it pursuant to Section 8.5.

Subparagraphs (c)(i), (ii) and (iii) shall be in lieu of Sections 315(d)(1),
315(d)(2) and 315(d)(3) of the TIA, respectively, and such Sections 315(d)(1),
315(d)(2) and 315(d)(3) are hereby expressly excluded from this Indenture, as
permitted by the TIA.

(d)  The Trustee may refuse to perform any duty or exercise any right or power
     or extend or risk its own funds or otherwise incur any financial liability
     unless it receives indemnity reasonably satisfactory to it against any
     loss, liability or expense.

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

(f)  The Trustee shall comply with the reporting requirements set forth in
     Section 313 of the TIA.

Section 9.2. Rights of Trustee.

Subject to its duties and responsibilities under the TIA and this Indenture,

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

                  (b)      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, conclusively rely upon an
         Officers' Certificate;

                  (c)      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;

                  (d)      the Trustee shall not be liable for any action taken,
         suffered, or omitted to be taken by it in good faith which it
         reasonably believes to be authorized or within its rights or powers
         conferred under this Indenture;

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

                  (f)      the Trustee shall be under no obligation to exercise
         any of the rights or powers vested in it by this Indenture at the
         request, order or direction of any of the Holders, pursuant to the
         provisions of this Indenture, unless such Holders shall have provided
         to the Trustee security or indemnity satisfactory to it against the
         costs, expenses and liabilities which may be incurred therein or
         thereby;

                                       34
<PAGE>

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

                  (h)      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 at the sole cost of the Company and shall incur no
         liability or additional liability of any kind by reason of such inquiry
         or investigation;

                  (i)      the Trustee shall not be deemed to have notice of any
         Default or Event of Default unless a Responsible Officer of the Trustee
         has actual knowledge thereof or unless written notice of any event
         which is in fact such a default is received by the Trustee at the
         Corporate Trust Office of the Trustee, and such notice references the
         Securities and this Indenture;

                  (j)      the rights, privileges, protections, immunities and
         benefits given to the Trustee, including, without limitation, its right
         to be indemnified, are extended to, and shall be enforceable by, the
         Trustee in each of its capacities hereunder, and to each agent,
         custodian and other person employed to act hereunder; and

                  (k)      the Trustee may request that the Company deliver an
         Officers' Certificate setting forth the names of individuals and/or
         titles of officers authorized at such time to take specified actions
         pursuant to this Indenture, which Officers' Certificate may be signed
         by any person authorized to sign an Officers' Certificate, including
         any person specified as so authorized in any such certificate
         previously delivered and not superseded.

Section 9.3. Individual Rights of Trustee.

The Trustee in its individual or any other capacity may become the owner or
pledgee of Securities and may otherwise deal with the Company or its Affiliates
with the same rights it would have if it were not Trustee. Any Paying Agent,
Registrar, Conversion Agent or co-registrar may do the same with like rights.
However, the Trustee must comply with Section 9.10 and Section 9.11.

Section 9.4. Trustee's Disclaimer.

The Trustee makes no representation as to the validity or adequacy of this
Indenture or the Securities, it shall not be accountable for the Company's use
or application of the proceeds from the Securities, it shall not be responsible
for any statement in any registration statement for the Securities under the
Securities Act or in any offering document for the Securities, this Indenture or
the Securities (other than its certificate of authentication), or the
determination as to which beneficial owners are entitled to receive any notices
hereunder.

Section 9.5. Notice of Defaults.

If a Default occurs and if it is known to the Trustee, the Trustee shall give to
each Holder notice of the Default within 90 calendar days after it occurs or, if
later, within 15 calendar days after it is known to the Trustee, unless such
Default shall have been cured or waived before the giving of such notice.
Notwithstanding the preceding sentence, except in the case of a Default
described in Section 8.1(a), Section 8.1(b), Section 8.1(d) or Section 8.1(e),
the Trustee may withhold the notice if and so long as the Responsible Officer in
good faith determines that withholding the notice is in the interest of the
Holders. The preceding sentence shall be in lieu of the proviso to Section
315(b) of the TIA and such proviso is hereby expressly excluded from this
Indenture, as permitted by the TIA.

                                       35
<PAGE>

Section 9.6. Reports by Trustee to Holders.

Within 60 days after each May 15 beginning with the May 15 following the date of
this Indenture, the Trustee shall mail to each Holder a brief report dated as of
such May 15 that complies with TIA Section 313(a), if required by such Section
313(a). The Trustee also shall comply with TIA Section 313(b).

A copy of each report at the time of its mailing to Holders shall be filed with
the SEC and each securities exchange, if any, on which the Securities are
listed. The Company agrees to notify the Trustee promptly whenever the
Securities become listed on any securities exchange and of any delisting
thereof.

Section 9.7. Compensation and Indemnity.

                  The Company agrees to:

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

                  (b)      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 reasonable expenses, advances and disbursements of
         its agents and counsel), except any such expense, disbursement or
         advance as may be attributable to its own negligence or willful
         misconduct; and

                  (c)      fully indemnify the Trustee or any predecessor
         Trustee and their agents for, and to hold them harmless against, any
         and all loss, damage, claim, liability, cost or expense (including
         attorney's fees and expenses, and taxes (other than taxes based upon,
         measured by or determined by the income of the Trustee)) incurred
         without the Trustee's negligent action, negligent failure to act or
         willful misconduct, arising out of or in connection with the acceptance
         or administration of this trust, including the costs and expenses of
         defending itself against any claim (whether asserted by the Company or
         any Holder or any other person) or liability in connection with the
         exercise or performance of any of its powers or duties hereunder, or in
         connection with enforcing the provisions of this Section 9.7.

With regard to its indemnification rights under Section 9.7(c) where the Company
has assumed the defense in any action or proceeding, the Trustee shall have the
right to employ separate counsel in any such action or proceeding and
participate in the investigation and defense thereof, and the Company shall pay
the reasonable fees and expenses of such separate counsel; provided, however,
that the Trustee may only employ separate counsel at the expense of the Company
if in the judgment of the Trustee (i) a conflict of interest exists by reason of
common representation or (ii) there are legal defenses available to the Trustee
that are different from or are in addition to those available to the Company or
if all parties commonly represented do not agree as to the action (or inaction)
of counsel.

To secure the Company's payment obligations in this Section 9.7, the Trustee
shall have a lien prior to the Securities on all money or property held or
collected by the Trustee, except that held in trust to pay the principal amount,
Redemption Price, Purchase Price, Designated Event Purchase Price or interest
and Additional Interest, if any, as the case may be, on particular Securities.

The Company's payment obligations pursuant to this Section 9.7 shall survive the
discharge of this Indenture and the resignation or removal of the Trustee. When
the Trustee incurs expenses after the occurrence of a Default specified in
Section 8.1(j) or Section 8.1(k), the expenses including the reasonable charges
and expenses of its counsel, are intended to constitute expenses of
administration under any Bankruptcy Law.

Section 9.8. Replacement of Trustee.

The Trustee may resign by so notifying the Company; provided, however, that no
such resignation shall be effective until a successor Trustee has accepted its
appointment pursuant to this Section 9.8. The

                                       36
<PAGE>

Holders of a majority in aggregate principal amount of the Securities at the
time outstanding may remove the Trustee by so notifying the Trustee and the
Company. The Company shall remove the Trustee if:

     (a) the Trustee fails to comply with Section 9.10;

     (b) the Trustee is adjudged bankrupt or insolvent;

     (c) a receiver or public officer takes charge of the Trustee or its
          property; or

     (d) the Trustee otherwise becomes incapable of acting.

If the Trustee resigns or is removed or if a vacancy exists in the office of
Trustee for any reason, the Company shall promptly appoint, by resolution of its
Board of Directors, a successor Trustee.

A successor Trustee shall deliver a written acceptance of its appointment to the
retiring Trustee and to the Company satisfactory in form and substance to the
retiring Trustee and the Company. Thereupon the resignation or removal of the
retiring Trustee shall become effective, and the successor Trustee shall have
all the rights, powers and duties of the Trustee under this Indenture. The
successor Trustee shall mail a notice of its succession to Holders. The retiring
Trustee shall promptly transfer all property held by it as Trustee to the
successor Trustee, upon payment of all the retiring Trustee's fees and expenses
then due and payable and subject to the lien provided for in Section 9.7.

If a successor Trustee does not take office within 30 days after the retiring
Trustee resigns or is removed, the retiring Trustee, the Company or the Holders
of a majority in aggregate principal amount of the Securities at the time
outstanding may petition at the expense of the Company any court of competent
jurisdiction at the expense of the Company for the appointment of a successor
Trustee.

If the Trustee fails to comply with Section 9.10, any Holder may petition any
court of competent jurisdiction for the removal of the Trustee and the
appointment of a successor Trustee.

Section 9.9. Successor Trustee by Merger.

If the Trustee consolidates with, merges or converts into, or transfers all or
substantially all its corporate trust business or assets to, another
corporation, the resulting, surviving or transferee corporation without any
further act shall be the successor Trustee.

Section 9.10. Eligibility; Disqualification.

The Trustee and any successor Trustee shall at all times satisfy the
requirements of TIA Sections 310(a)(1) and 310(b). The Trustee (or its parent
holding company) shall have a combined capital and surplus of at least
$50,000,000 as set forth in its most recent published annual report of
condition. Nothing contained herein shall prevent the Trustee from filing with
the Commission the application referred to in the penultimate paragraph of TIA
Section 310(b). If at any time the Trustee shall cease to be eligible in
accordance with the provisions of this Section 9.10, it shall resign immediately
in the manner and with the effect hereinafter specified in this Article.

Section 9.11. Preferential Collection of Claims Against Company.

The Trustee shall comply with TIA Section 311(a), excluding any creditor
relationship listed in TIA Section 311(b). A Trustee who has resigned or been
removed shall be subject to TIA Section 311(a) to the extent indicated therein.

                                   ARTICLE X

                             DISCHARGE OF INDENTURE

Section 10.1. Discharge of Liability on Securities.

When (i) the Company delivers to the Trustee all outstanding Securities (other
than Securities replaced or repaid pursuant to Section 2.7) for cancellation or
(ii) all outstanding Securities have become due and payable (whether at the
Stated Maturity or upon acceleration, or on any Redemption Date, Purchase Date
or Designated Event Purchase Date, or upon conversion) and the Company deposits
with the Paying

                                       37
<PAGE>

Agent or Conversion Agent cash or Applicable Stock sufficient to pay all amounts
due and owing on all outstanding Securities (other than Securities replaced
pursuant to Section 2.7), and if in either case the Company pays all other sums
payable hereunder by the Company, then this Indenture shall, subject to Section
9.7, cease to be of further effect. The Trustee shall join in the execution of a
document prepared by the Company acknowledging satisfaction and discharge of
this Indenture on demand of the Company accompanied by an Officers' Certificate
and Opinion of Counsel and at the cost and expense of the Company.

Section 10.2. Repayment to the Company.

The Trustee and the Paying Agent shall return to the Company upon written
request any cash or securities held by them for the payment of any amount with
respect to the Securities that remains unclaimed for two years, subject to
applicable unclaimed property law. After return to the Company, Holders entitled
to the cash or securities must look to the Company for payment as general
creditors unless an applicable abandoned property law designates another person
and the Trustee and the Paying Agent shall have no further liability to the
Holders with respect to such cash or securities for that period commencing after
the return thereof.

                                   ARTICLE XI

                                   AMENDMENTS

Section 11.1. Without Consent of Holders.

The Company and the Trustee may amend this Indenture or the Securities without
the consent of any Holder to:

                  (a)      add to the covenants of the Company for the benefit
         of the Holders of Securities;

                  (b)      surrender any right or power herein conferred upon
         the Company;

                  (c)      provide for conversion rights of Holders of
         Securities if any reclassification or change of the Common Stock or any
         consolidation, merger or sale of all or substantially all of the
         Company's assets occurs;

                  (d)      provide for the assumption of the Company's
         obligations to the Holders of Securities in the case of a merger,
         consolidation, conveyance, transfer, sale, lease or other disposition
         pursuant to Article VII;

                  (e)      increase the Conversion Rate; provided, however, that
         such increase in the Conversion Rate shall not adversely affect the
         interests of the Holders of Securities (after taking into account tax
         and other consequences of such increase);

                  (f)      comply with the requirements of the SEC in order to
         effect or maintain the qualification of this Indenture under the TIA;

                  (g)      make any changes or modifications necessary in
         connection with the registration of the Securities under the Securities
         Act as contemplated in the Registration Rights Agreement; provided,
         however, that such action pursuant to this clause (g) does not, in the
         good faith opinion of the Board of Directors (as evidenced by a Board
         Resolution), adversely affect the interests of the Holders of
         Securities in any material respect;

                  (h)      cure any ambiguity, correct or supplement any
         provision herein which may be inconsistent with any other provision
         herein or which is otherwise defective, or to make any other provisions
         with respect to matters or questions arising under this Indenture which
         the Company may deem necessary or desirable and which shall not be
         inconsistent with the provisions of this Indenture; provided,

                                       38
<PAGE>

         however, that such action pursuant to this clause (h) does not, in the
         good faith opinion of the Board of Directors (as evidenced by a Board
         Resolution), adversely affect the interests of the Holders of
         Securities in any material respect;

(i)  to evidence the succession of another Person to the Company or any
     other obligor upon the Securities, and the assumption by any such successor
     of the covenants of the Company or such obligor herein and in the
     Securities, in each case in compliance with the provisions of this
     Indenture;

(j)  to evidence and provide the acceptance of the appointment of a successor
     trustee hereunder; or

                  (k)      add or modify any other provisions herein with
         respect to matters or questions arising hereunder which the Company and
         the Trustee may deem necessary or desirable and which shall not
         adversely affect the interests of the Holders of Securities.

Section 11.2. With Consent of Holders.

Except as provided below in this Section 11.2, this Indenture or the Securities
may be amended, modified or supplemented, and noncompliance in any particular
instance with any provision of this Indenture or the Securities may be waived,
in each case with the written consent or affirmative vote of the Holders of at
least a majority of the principal amount of the Securities at the time
outstanding.

Without the written consent or the affirmative vote of each Holder of Securities
affected thereby (in addition to the written consent or the affirmative vote of
the holders of at least a majority of the principal amount of the Securities at
the time outstanding), an amendment or waiver under this Section 11.2 may not:

                  (a)      change the maturity of the principal amount of, or
         the payment date of any installment of interest or Additional Interest,
         if any, on, any Security;

                  (b)      reduce the principal amount of, or interest or
         Additional Interest, if any, on, or the Redemption Price, Purchase
         Price or Designated Event Purchase Price of, any Security;

                  (c)      change the currency of payment of principal amount
         of, or interest or Additional Interest, if any, on, or the Redemption
         Price, Purchase Price or Designated Event Purchase Price of, any
         Security from U.S. Dollars;

                  (d)      impair or adversely affect the rate of accrual of
         interest or Additional Interest, if any, on any Security, or the manner
         of calculation thereof;

                  (e)      impair the right of any Holder to institute suit for
         the enforcement of any payment or with respect to, or conversion of,
         any Security;

                  (f)      impair or adversely affect the conversion rights of
         the Holder of the Securities as provided in Article XII;

                  (g)      impair or adversely affect the purchase rights of the
         Holders of the Securities as provided in Article IV or Article V;

                  (h)      modify the optional redemption provisions of Article
         III in a manner adverse to the Holders of the Securities;

                  (i)      reduce the percentage of the principal amount of the
         outstanding Securities the written consent or affirmative vote of whose
         Holders is required for any such supplemental indenture;

                                       39
<PAGE>

                  (j)      reduce the percentage of the principal amount of the
         outstanding Securities the written consent or affirmative vote of whose
         Holders is required for any waiver of any past Default provided for in
         this Indenture; or

                  (k)      waive any matter set forth in Section 8.4(a), Section
         8.4(b), or Section 8.4(c).

It shall not be necessary for the consent of the Holders under this Section 11.2
to approve the particular form of any proposed amendment, but it shall be
sufficient if such consent approves the substance thereof.

After an amendment under this Section 11.2 becomes effective, the Company shall
mail to each Holder a notice briefly describing the amendment.

Nothing contained in this Section 11.2 shall impair the ability of the Company
and the Trustee to amend this Indenture or the Securities without the consent of
any Holder to provide for the assumption of the Company's obligations to the
Holders of Securities in the case of a merger, consolidation, conveyance,
transfer, sale, lease or other disposition pursuant to Article VII.

Section 11.3. Compliance with Trust Indenture Act.

Every supplemental indenture executed pursuant to this Article shall comply with
the TIA.

Section 11.4. Revocation and Effect of Consents, Waivers and Actions.

Until an amendment, waiver or other action by Holders becomes effective, a
consent thereto by a Holder of a Security hereunder is a continuing consent by
the Holder and every subsequent Holder of that Security or portion of the
Security that evidences the same obligation as the consenting Holder's Security,
even if notation of the consent, waiver or action is not made on the Security.
However, any such Holder or subsequent Holder may revoke the consent, waiver or
action as to such Holder's Security or portion of the Security if the Trustee
receives the notice of revocation before the date the amendment, waiver or
action becomes effective. After an amendment, waiver or action becomes
effective, it shall bind every Holder.

Section 11.5. Notation on or Exchange of Securities.

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

Section 11.6. Trustee to Sign Supplemental Indentures.

The Trustee shall sign any supplemental indenture authorized pursuant to this
Article XI if the amendment contained therein does not adversely affect the
rights, duties, liabilities or immunities of the Trustee. If it does, the
Trustee may, but need not, sign such supplemental indenture. In signing such
supplemental indenture the Trustee shall receive, and (subject to the provisions
of Section 9.1) shall be fully protected in relying upon, an Officers'
Certificate and an Opinion of Counsel stating that such amendment is authorized
or permitted by this Indenture.

Section 11.7. 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.

                                       40
<PAGE>

                                  ARTICLE XII

                                   CONVERSION

Section 12.1. Conversion Right.

(a)  Subject to and upon compliance with the provisions of this Article XII, a
     Holder of a Security shall have the right, at such Holder's option, to
     convert all or any portion (if the portion to be converted is $1,000 or an
     integral multiple of $1,000) of such Security into Common Stock:

     (i)  during any Conversion Period, and only during such Conversion Period
          commencing after the date hereof, if, on each of at least 20 Trading
          Days in the period of 30 consecutive Trading Days ending on the first
          Trading Day of the Conversion Period, the Closing Sale Price of the
          Common Stock exceeds 120% of the Conversion Price in effect on such
          30th Trading Day of such period;

     (ii) if such Security has been called for redemption pursuant to Article
          III; or

     (iii) as provided in clause (b) of this Section 12.1.

     The Conversion Agent shall, on behalf of the Company, determine on a daily
     basis whether the Securities shall be convertible as a result of the
     occurrence of an event specified in clause (i) above and, if the Securities
     shall be so convertible, the Conversion Agent shall promptly deliver to the
     Company and the Trustee written notice thereof. Whenever the Securities
     shall become convertible pursuant to this Section 12.1, the Company or, at
     the Company's request, the Trustee in the name and at the expense of the
     Company, shall notify the Holders of the event triggering such
     convertibility in the manner provided in Section 13.2, and the Company
     shall also publish such information on the Company's website, or through
     such other public medium that reasonably could be expected to inform
     Holders of such information. Any notice so given shall be conclusively
     presumed to have been duly given, whether or not the Holder receives such
     notice. Securities called for redemption may be converted at any time on
     and after the date that the Company gives notice to the Holders of such
     right until 5:00 p.m., New York city time, on the second Business Day
     preceding the corresponding Redemption Date.

     With respect to any conversion of a Security during a Registration Default
     Period following satisfaction of any of the conditions to conversion
     described in clauses (i) through (iii) above (and during the prescribed
     time periods in respect thereof), a Holder shall be entitled to, subject to
     Section 12.13, 103% of the number of shares of Common Stock that the Holder
     would have otherwise been entitled to upon conversion.

(b)  (i) In the event that:

          (A)  the Company distributes to all holders of its Common Stock rights
               or warrants entitling them (for a period expiring within 60 days
               of the Record Date for such distribution) to subscribe for or
               purchase Common Stock at a price per share of Common Stock less
               than the Closing Sale Price of the Common Stock on the Business
               Day immediately preceding the announcement of such distribution;

          (B)  the Company distributes to all holders of its Common Stock cash
               or other assets, debt securities or rights or warrants to
               purchase its securities, including the declaration of any cash
               dividends, payable quarterly or otherwise, where the Fair Market
               Value (as determined by the Board of Directors) of such
               distribution per share of Common Stock exceeds 10% of the Closing
               Sale Price of the Common Stock on the Business Day immediately
               preceding the date of declaration of such distribution; or

          (C)  a Designated Event occurs,

     then, in each case, the Securities may be surrendered for conversion at any
     time on and after the date that the Company gives notice to the Holders of
     such right, which shall be, in the case of (A) or (B), not less than 15
     Business Days prior to the Ex-Dividend Time for such distribution, or, in
     the case of (C), within 15 Business

                                       41
<PAGE>
     Days after the occurrence of the Designated Event, until 5:00 p.m., New
     York City time, on the earlier of the Business Day immediately preceding
     the Ex-Dividend Time and the date the Company announces that such
     distribution shall not take place in the case of (A) or (B), or within 20
     Business Days of the Company's delivery of the notice of the Designated
     Event in the case of (C); provided, however, that in the case of (A) or
     (B), a Holder of Securities may not surrender Securities for conversion if
     the Holder shall otherwise participate in such distribution without
     conversion.

     (ii) In addition, in the event that the Company consolidates with or merges
          into another corporation, or is a party to a binding share exchange
          pursuant to which the Common Stock would be converted into cash,
          securities or other property as set forth in Section 12.4, then the
          Securities may be surrendered for conversion at any time from and
          after the date which is 15 calendar days prior to the date announced
          by the Company as the anticipated effective time of such transaction
          until 15 calendar days after the actual date of such transaction.

Section 12.2. Conversion Procedures; Conversion Rate; Fractional Shares.

(a)  Subject to Section 12.13, each Security shall be convertible at the office
     of the Conversion Agent into fully paid and nonassessable shares of Common
     Stock (calculated to the nearest 1/10,000th of a share).

     The Conversion Agent shall notify the Company when it receives a Conversion
     Notice. Pursuant to Section 12.13, the Company shall determine the number
     of shares of Common Stock and/or the amount of cash, if any, that the
     Holder that submitted the Conversion Notice is entitled to receive upon
     surrender of the Securities covered by that Conversion Notice. If the
     Company elects to settle in Common Stock only, a certificate for the number
     of full shares of Common Stock into which the Securities are converted (and
     cash in lieu of fractional shares) shall be delivered to such Holder,
     assuming all of the other requirements have been satisfied by such Holder,
     as soon as practicable after the Company issues its notification of its
     chosen method of settlement, in accordance with Section 12.13. If the
     Company elects to settle in cash or a combination of cash and Common Stock,
     the cash and, if applicable, a certificate for the number of full shares of
     Common Stock into which the Securities are converted (and cash in lieu of
     fractional shares) shall be delivered to such Holder, assuming all of the
     other requirements have been satisfied by such Holder, in accordance with
     Section 12.13. Notwithstanding the foregoing, the Company shall not be
     required to deliver certificates for Common Stock while the stock transfer
     books for such stock or the security register are duly closed for any
     purpose, but certificates for Common Stock shall be issued and delivered as
     soon as practicable after the opening of such books or security register.

     No cash payment of accrued and unpaid interest or Additional Interest shall
     be paid by the Company on a converted Security, except as described in
     Section 12.9. Accrued and unpaid interest and Additional Interest, if any,
     shall be deemed to be paid in full with the shares of Common Stock issued
     or cash paid upon conversion, rather than deemed cancelled, extinguished or
     forfeited.

     If the Common Stock, cash or combination of Common Stock and cash received
     upon conversion of a Security pursuant to this Article XII does not include
     cash sufficient to comply with the United States federal withholding tax
     obligations imposed by the Code with respect to accrued and unpaid interest
     on the Securities payable to the beneficial owner of such Security, the
     Company may, to the extent required by applicable law, recoup or set-off
     such liability against either the Common Stock to be issued upon conversion
     to such beneficial owner or any actual cash dividends or distributions
     subsequently made with respect to such Common Stock to such beneficial
     owner.

     In the event of a Designated Event, if a Holder has submitted any or all of
     its Securities for repurchase, a Holder's conversion rights on the
     Securities so subject to repurchase shall expire at 5:00 p.m., New York
     City time, on the Business Day immediately preceding the Designated Event
     Purchase Date. Notwithstanding the foregoing, a Security in respect of
     which a Holder has delivered a Designated Event Purchase Notice exercising
     such Holder's right to require the Company to repurchase such Security may
     be converted only if such Designated Event Purchase Notice is withdrawn in
     accordance with Section 4.2(b) prior to 5:00 p.m., New York City time, on
     the Business Day immediately preceding the Designated Event Purchase Date.

(b)  Before any Holder shall be entitled to convert the same into Common Stock,
     such Holder shall, in the case of Global Securities, comply with the
     Applicable Procedures of the Depositary in effect at that time, and in the
     case of Certificated Securities, surrender such Securities, duly endorsed
     to the Company or in blank, at the office of the Conversion Agent, and
     shall give written notice to the Company at said office or place in the
     form of the

                                       42
<PAGE>

     Conversion Notice attached to the Security (the "CONVERSION NOTICE") that
     such Holder elects to convert the same and shall state in writing therein
     the principal amount of Securities to be converted (in whole or in part so
     long as the principal amount to be converted is in multiples of $1,000
     principal amount) and the name or names (with addresses) in which such
     Holder wishes the certificate or certificates for Common Stock to be
     issued.

     Before any such conversion, a Holder also shall pay all funds required, if
     any, relating to interest or Additional Interest, if any, on the
     Securities, as provided in Section 12.9 and all taxes or duties, if any, as
     provided in Section 12.8.

     If more than one Security shall be surrendered for conversion at one time
     by the same Holder, the number of full shares of Common Stock that shall be
     deliverable upon conversion shall be computed on the basis of the aggregate
     principal amount of the Securities (or specified portions thereof to the
     extent permitted thereby) so surrendered.

     If Common Stock to be issued upon conversion of a Restricted Security are
     to be issued in the name of a Person other than the Holder of such
     Restricted Security, such Holder shall deliver to the Conversion Agent a
     certification in substantially the form set forth in a Transfer Certificate
     dated the date of surrender of such Restricted Security and signed by such
     Holder, as to compliance with the restrictions on transfer applicable to
     such Restricted Security. The Company shall not be required to issue Common
     Stock upon conversion of any such Restricted Security to a Person other
     than the Holder if such Restricted Security is not so accompanied by a
     properly completed certification, and the Registrar shall not be required
     to register Common Stock upon conversion of any such Restricted Security in
     the name of a Person other than the Holder if such Restricted Security is
     not so accompanied by a properly completed certification.

(c)  A Security shall be deemed to have been converted immediately prior to 5:00
     p.m., New York City time, on the date on which all of the conversion
     requirements set forth in Section 12.2(b) have been satisfied, and the
     person or persons entitled to receive the Common Stock issuable upon such
     conversion shall be treated for all purposes as the record Holder or
     Holders of such Common Stock as of 5:00 p.m., New York City time, on such
     date.

(d)  In case any Certificated Security shall be surrendered for partial
     conversion, the Company shall execute and the Trustee shall authenticate
     and deliver to or upon the written order of the Holder of the Security so
     surrendered, without charge to such Holder (subject to the provisions of
     Section 12.8), a new Security or Securities in authorized denominations in
     an aggregate principal amount equal to the unconverted portion of the
     surrendered Certificated Securities.

Section 12.3. Adjustment of Conversion Rate.

The Conversion Rate shall be adjusted from time to time as follows:

(a)  In case the Company shall, at any time or from time to time while any of
     the Securities are outstanding, pay a dividend or make a distribution in
     Common Stock to all or substantially all holders of its outstanding Common
     Stock, then the Conversion Rate in effect immediately prior to the close of
     business on the Record Date fixed for the determination of stockholders
     entitled to receive such dividend or other distribution shall be adjusted
     so that the Holder of any Security thereafter surrendered for conversion
     shall be entitled to receive that number of shares of Common Stock which it
     would have received had such Security been converted immediately prior to
     the happening of such event as well as such additional shares it would have
     received as a result of such event. Such adjustment shall become effective
     immediately prior to the opening of business on the day following the
     Record Date fixed for such determination. If any dividend or distribution
     of the type described in this Section 12.3(a) is declared but not so paid
     or made, the Conversion Rate shall again be adjusted to the Conversion Rate
     which would then be in effect if such dividend or distribution had not been
     declared.

(b)  In case the Company shall, at any time or from time to time while any of
     the Securities are outstanding, subdivide its outstanding shares of Common
     Stock into a greater number of Common Stock or combine its outstanding
     shares of Common Stock into a smaller number of Common Stock, then the
     Conversion Rate in effect immediately prior to the close of business on the
     day upon which such subdivision or combination becomes effective shall be
     adjusted so that the Holder of any Security thereafter surrendered for
     conversion shall be entitled to receive that number of shares of Common
     Stock which it would have received had such Security

                                       43
<PAGE>

     been converted immediately prior to the happening of such event as well as
     such additional shares as it would have received as a result of such event.

     Such adjustment shall become effective immediately prior to the opening of
     business on the day following the day upon which such subdivision or
     combination becomes effective.

(c)  In case the Company shall, at any time or from time to time while any of
     the Securities are outstanding, issue rights or warrants for a period
     expiring within 60 days (other than any rights or warrants referred to in
     Section 12.3(d)) to all or substantially all holders of its outstanding
     Common Stock entitling them to subscribe for or purchase Common Stock (or
     securities convertible into or exchangeable or exercisable for Common
     Stock), at a price per share of Common Stock (or having a conversion,
     exchange or exercise price per share of Common Stock) less than the Closing
     Sale Price of the Common Stock on the Business Day immediately preceding
     the date of announcement of such issuance (treating the conversion,
     exchange or exercise price per share of Common Stock of the securities
     convertible, exchangeable or exercisable into Common Stock as equal to (x)
     the sum of (i) the price for a unit of the security convertible into or
     exchangeable or exercisable for Common Stock and (ii) any additional
     consideration initially payable upon the conversion of or exchange or
     exercise for such security into Common Stock divided by (y) the number of
     shares of Common Stock initially underlying such convertible, exchangeable
     or exercisable security), then the Conversion Rate shall be adjusted by
     multiplying the Conversion Rate in effect at the opening of business on the
     date after such date of announcement by a fraction:

                  (i)      the numerator of which shall be the number of shares
         of Common Stock outstanding at the close of business on the date of
         announcement, plus the total number of additional shares of Common
         Stock so offered for subscription or purchase (or into which the
         convertible, exchangeable or exercisable securities so offered are
         convertible, exchangeable or exercisable); and

                  (ii)     the denominator of which shall be the number of
         shares of Common Stock outstanding on the close of business on the date
         of announcement, plus the number of shares of Common Stock (or
         convertible, exchangeable or exercisable securities) which the
         aggregate offering price of the total number of shares of Common Stock
         (or convertible, exchangeable or exercisable securities) so offered for
         subscription or purchase (or the aggregate conversion, exchange or
         exercise price of the convertible, exchangeable or exercisable
         securities so offered) would purchase at such Closing Sale Price of the
         Common Stock.

     Such adjustment shall become effective immediately prior to the opening of
     business on the day following the Record Date for such determination. To
     the extent that shares of Common Stock (or securities convertible,
     exchangeable or exercisable into shares of Common Stock) are not delivered
     pursuant to such rights or warrants, upon the expiration or termination of
     such rights or warrants, the Conversion Rate shall be readjusted to the
     Conversion Rate which would then be in effect had the adjustments made upon
     the issuance of such rights or warrants been made on the basis of the
     delivery of only the number of shares of Common Stock (or securities
     convertible, exchangeable or exercisable into shares of Common Stock)
     actually delivered. In the event that such rights or warrants are not so
     issued, the Conversion Rate shall again be adjusted to be the Conversion
     Rate which would then be in effect if the Record Date fixed for the
     determination of stockholders entitled to receive such rights or warrants
     had not been fixed. In determining whether any rights or warrants entitle
     the holders to subscribe for or purchase shares of Common Stock at less
     than such Closing Sale Price, and in determining the aggregate offering
     price of such shares of Common Stock, there shall be taken into account any
     consideration received for such rights or warrants, the value of such
     consideration if other than cash, to be determined by the Board of
     Directors.

(d)  (A) In case the Company shall, at any time or from time to time while any
     of the Securities are outstanding, by dividend or otherwise, distribute to
     all or substantially all holders of its outstanding shares of Common Stock
     (including any such distribution made in connection with a consolidation or
     merger in which the Company is the continuing corporation and the shares of
     Common Stock are not changed or exchanged), shares of its capital stock,
     evidences of its Indebtedness or other assets, including securities, but
     excluding (i) dividends or distributions of Common Stock referred to in
     Section 12.3(a), (ii) any rights or warrants referred to in Section

                                       44
<PAGE>

     12.3(c), (iii) dividends and distributions paid exclusively in cash
     referred to in Section 12.3(e) and (iv) dividends and distributions of
     stock, securities or other property or assets (including cash) in
     connection with the reclassification, change, merger, consolidation,
     statutory share exchange, combination, sale or conveyance to which Section
     12.4 applies (such capital stock, evidence of its indebtedness, other
     assets or securities being distributed hereinafter in this Section 12.3(d)
     called the "DISTRIBUTED ASSETS"), then, in each such case, subject to
     paragraphs (D) and (E) of this Section 12.3(d), the Conversion Rate shall
     be adjusted by multiplying the Conversion Rate in effect immediately prior
     to the close of business on the Record Date with respect to such
     distribution by a fraction:

                  (i)      the numerator of which shall be the Current Market
         Price; and

                  (ii)     the denominator of which shall be such Current Market
         Price of the Common Stock, less the Fair Market Value on such date of
         the portion of the distributed assets so distributed applicable to one
         share of Common Stock (determined on the basis of the number of shares
         of Common Stock outstanding on the Record Date) on such date.

     Such adjustment shall become effective immediately prior to the opening of
     business on the day following the Record Date for such distribution. In the
     event that such dividend or distribution is not so paid or made, the
     Conversion Rate shall again be adjusted to be the Conversion Rate which
     would then be in effect if such dividend or distribution had not been
     declared.

                           (B)      If the Board of Directors determines the
         Fair Market Value of any distribution for purposes of this Section
         12.3(d) by reference to the actual or when issued trading market for
         any distributed assets comprising all or part of such distribution, it
         must in doing so consider the prices in such market over the same
         period (the "REFERENCE PERIOD") used in computing the Current Market
         Price pursuant to Section 12.3(g) to the extent possible, unless the
         Board of Directors determines in good faith that determining the Fair
         Market Value during the Reference Period would not be in the best
         interest of the Holders.

(C)  In the event any such distribution consists of shares of capital stock of,
     or similar equity interests in, one or more of the Company's Subsidiaries
     (a "SPIN-OFF"), the Fair Market Value of the securities to be distributed
     shall equal the average of the Closing Sale Prices of such securities on
     the principal securities market on which such securities are traded for the
     five consecutive Trading Days commencing on and including the sixth Trading
     Day of those securities after the effectiveness of the Spin-Off, and the
     Current Market Price shall be measured for the same period. In the event,
     however, that an underwritten initial public offering of the securities in
     the Spin-Off occurs simultaneously with the Spin-Off, Fair Market Value of
     the securities distributed in the Spin-Off shall mean the initial public
     offering price of such securities and the Current Market Price shall mean
     the Closing Sale Price for the Common Stock on the same Trading Day.

(D)  Rights or warrants distributed by the Company to all holders of its
     outstanding shares of Common Stock entitling them to subscribe for or
     purchase shares of Equity Interest (either initially or under certain
     circumstances), which rights or warrants, until the occurrence of a
     specified event or events ("TRIGGER EVENT"), (x) are deemed to be
     transferred with such Common Stock, (y) are not exercisable and (z) are
     also issued in respect of future issuances of Common Stock shall be deemed
     not to have been distributed for purposes of this Section 12.3(d) (and no
     adjustment to the Conversion Rate under this Section 12.3(d) shall be
     required) until the occurrence of the earliest Trigger Event. If such right
     or warrant is subject to subsequent events, upon the occurrence of which
     such right or warrant shall become exercisable to purchase different
     distributed assets, evidences of indebtedness or other assets, or entitle
     the holder to purchase a different number or amount of the foregoing or to
     purchase any of the foregoing at a different purchase price, then the
     occurrence of each such event shall be deemed to be the date of issuance
     and Record Date with respect to a new right or warrant (and a termination
     or expiration of the existing right or warrant without exercise by the
     holder thereof). In addition, in the event of any distribution (or deemed
     distribution) of rights or warrants, or any Trigger Event or other event
     (of the type described in the preceding sentence) with respect thereto,
     that resulted in an adjustment to the Conversion Rate under this Section
     12.3(d):

                                       45
<PAGE>
                  (iii)    in the case of any such rights or warrants which
         shall all have been redeemed or purchased without exercise by any
         holders thereof, the Conversion Rate shall be readjusted upon such
         final redemption or purchase to give effect to such distribution or
         Trigger Event, as the case may be, as though it were a cash
         distribution, equal to the per share redemption or Purchase Price
         received by a holder of Common Stock with respect to such rights or
         warrants (assuming such holder had retained such rights or warrants),
         made to all holders of Common Stock as of the date of such redemption
         or purchase; and

                  (iv)     in the case of such rights or warrants which shall
         have expired or been terminated without exercise, the Conversion Rate
         shall be readjusted as if such rights and warrants had never been
         issued.

                           (E)      For purposes of this Section 12.3(d) and
         Section 12.3(a), Section 12.3(b) and Section 12.3(c), any dividend or
         distribution to which this Section 12.3(d) is applicable that also
         includes (x) Common Stock, (y) a subdivision or combination of Common
         Stock to which Section 12.3(b) applies or (z) rights or warrants to
         subscribe for or purchase Common Stock to which Section 12.3(c) applies
         (or any combination thereof), shall be deemed instead to be:

                  (v)      a dividend or distribution of the evidences of
         indebtedness, assets, shares of capital stock, rights or warrants,
         other than such Common Stock, such subdivision or combination or such
         rights or warrants to which Section 12.3(a), Section 12.3(b) and
         Section 12.3(c) apply, respectively (and any Conversion Rate adjustment
         required by this Section 12.3(d) with respect to such dividend or
         distribution shall then be made), immediately followed by

                  (vi)     a dividend or distribution of such Common Stock, such
         subdivision or combination or such rights or warrants (and any further
         Conversion Rate adjustment required by Section 12.3(a), Section 12.3(b)
         and Section 12.3(c) with respect to such dividend or distribution shall
         then be made), except:

                           (1)  the Record Date of such dividend or distribution
         shall be substituted as (i) "the date fixed for the determination of
         stockholders entitled to receive such dividend or other distribution,"
         "Record Date fixed for such determinations" and "Record Date" within
         the meaning of Section 12.3(a), (ii) "the day upon which such
         subdivision or combination becomes effective" within the meaning of
         Section 12.3(b), and (iii) as "the Record Date fixed for the
         determination of the stockholders entitled to receive such rights or
         warrants" and such "Record Date" within the meaning of Section 12.3(c);
         and

                           (2)  any reduction or increase in the number of
         shares of Common Stock resulting from such subdivision or combination
         shall be disregarded in connection with such dividend or distribution.

                  (e)  In case the Company shall, at any time or from time to
time after the initial Issue Date while any of the Securities are outstanding,
by dividend or otherwise, distribute to all or substantially all holders of its
outstanding shares of Common Stock, cash (including any quarterly cash
dividends, but excluding any cash that is distributed upon a reclassification,
change, merger, consolidation, statutory share exchange, combination, sale or
conveyance to which Section 12.4 applies or as part of a distribution referred
to in Section 12.3(d)), then, and in each case, immediately after the close of
business on such date, the Conversion Rate shall be adjusted by multiplying the
Conversion Rate in effect immediately prior to the close of business of such
Record Date by a fraction:

                           (A)  the numerator of which shall be equal to the
         Current Market Price on such date; and

                           (B)  the denominator of which shall be equal to the
         Current Market Price on the Record Date, less an amount equal to the
         quotient of (x) the aggregate amount of such cash distribution and (y)
         the number of shares of Common Stock outstanding on the Record Date.

                                       46
<PAGE>
         Such adjustment shall become effective immediately prior to the opening
         of business on the day following the Record Date for such distribution.
         In the event that such distribution is not so made, the Conversion Rate
         shall again be adjusted to be the Conversion Rate which would then be
         in effect if such distribution had not been declared.

(f)  In case a tender offer or exchange offer (other than as part of a stock
     option exchange offer) made by the Company or any of its Subsidiaries for
     all or any portion of the Common Stock shall expire, then and in each such
     case, immediately prior to the opening of business on the day after the
     date of the last time (the "EXPIRATION TIME") tenders or exchanges could
     have been made pursuant to such tender offer or exchange offer, the
     Conversion Rate shall be adjusted so that the same shall equal the rate
     determined by multiplying the Conversion Rate in effect immediately prior
     to the close of business on the date of the Expiration Time by a fraction:

                  (A)  the numerator of which shall be the sum of (x) the
         product of (i) the number of shares of Common Stock outstanding
         (excluding any tendered or exchanged shares) at the Expiration Time and
         (ii) the Current Market Price of the Common Stock at the Expiration
         Time, and (y) the Fair Market Value of the aggregate consideration
         payable to stockholders based on acceptance (up to any maximum
         specified in the terms of the tender offer or exchange offer) of all
         shares validly tendered and not withdrawn as of the Expiration Time;
         and

                  (B)  the denominator of which shall be the product of the
         number of shares of Common Stock outstanding (including any tendered or
         exchanged shares) at the Expiration Time and the Current Market Price
         of the Common Stock at the Expiration Time.

Such adjustment (if any) shall become effective immediately prior to the opening
of business on the day following the Expiration Time. In the event that the
Company is obligated to purchase shares pursuant to any such tender offer or
exchange offer, but the Company is permanently prevented by applicable law from
effecting any such purchases or all or a portion of such purchases are
rescinded, the Conversion Rate shall again be adjusted to be the Conversion Rate
which would then be in effect if such (or such portion of the) tender offer or
exchange offer had not been made. If the application of this Section 12.3(e) to
any tender offer or exchange offer would result in a decrease in the Conversion
Rate, no adjustment shall be made for such tender offer under this Section
12.3(e).

To the extent the Company has a rights plan in effect upon the conversion of the
Securities, if Holders of the Securities exercising the right of conversion
attaching after the date the rights separate from the underlying Common Stock
are not entitled to receive the rights that would otherwise be attributable to
the Common Stock received upon conversion, the Conversion Rate shall be adjusted
as though the rights were being distributed to holders of Common Stock on the
date of such separation. If such an adjustment is made and the rights are later
redeemed, invalidated or terminated, then a corresponding reversing adjustment
shall be made to the Conversion Rate on an equitable basis.

(g)  For purposes of this Article XII, the following terms shall have the
     meanings indicated:

     "CURRENT MARKET PRICE" on any date means the average of the daily Closing
     Sale Prices per share of Common Stock for the ten consecutive Trading Days
     immediately prior to such date; provided, however, that if:

                  (i)      the "ex" date (as hereinafter defined) for any event
         (other than the issuance or distribution requiring such computation)
         that requires an adjustment to the Conversion Rate pursuant to Section
         12.3(a), Section 12.3(b), Section 12.3(c), Section 12.3(d), Section
         12.3(e) or Section 12.3(f) occurs during such ten consecutive Trading
         Days, the Closing Sale Price for each Trading Day prior to the "ex"
         date for such other event shall be adjusted by multiplying such Closing
         Sale Price by the same fraction by which the Conversion Rate is so
         required to be adjusted as a result of such other event;

                  (ii)     the "ex" date for any event (other than the issuance
         or distribution requiring such computation) that requires an adjustment
         to the Conversion Rate pursuant to Section 12.3(a), Section 12.3(b),
         Section 12.3(c), Section 12.3(d), Section 12.3(e) or Section 12.3(f)
         occurs on or after the "ex" date for the issuance or distribution
         requiring such computation and prior to the day

                                       47
<PAGE>

         in question, the Closing Sale Price for each Trading Day on and after
         the "ex" date for such other event shall be adjusted by multiplying
         such Closing Sale Price by the reciprocal of the fraction by which the
         Conversion Rate is so required to be adjusted as a result of such other
         event; and

                  (iii)    the "ex" date for the issuance or distribution
         requiring such computation is prior to the day in question, after
         taking into account any adjustment required pursuant to clause (1) or
         (2) of this proviso, the Closing Sale Price for each Trading Day on or
         after such "ex" date shall be adjusted by adding thereto the amount of
         any cash and the Fair Market Value (as determined by the Board of
         Directors in a manner consistent with any determination of such value
         for purposes of Section 12.3(d), Section 12.3(e) or Section 12.3(f)) of
         the evidences of Indebtedness, shares of capital stock or assets being
         distributed applicable to one share of Common Stock as of the close of
         business on the day before such "ex" date.

     For purposes of any computation under Section 12.3(e), if the "ex" date for
     any event (other than the tender offer requiring such computation) that
     requires an adjustment to the Conversion Rate pursuant to Section 12.3(a),
     Section 12.3(b), Section 12.3(c), Section 12.3(d), Section 12.3(e) or
     Section 12.3(f) occurs on or after the Expiration Time for the tender or
     exchange offer requiring such computation and prior to the day in question,
     the Closing Sale Price for each Trading Day on and after the "ex" date for
     such other event shall be adjusted by multiplying such Closing Sale Price
     by the reciprocal of the fraction by which the Conversion Rate is so
     required to be adjusted as a result of such other event. For purposes of
     this paragraph, the term "ex" date, when used:

                  (iv)     with respect to any issuance or distribution, means
         the first date on which the Common Stock trade regular way on the
         relevant exchange or in the relevant market from which the Closing Sale
         Price was obtained without the right to receive such issuance or
         distribution;

                  (v)      with respect to any subdivision or combination of
         Common Stock, means the first date on which the Common Stock trade
         regular way on such exchange or in such market after the time at which
         such subdivision or combination becomes effective; and

                  (vi)     with respect to any tender offer or exchange offer,
         means the first date on which the Common Stock trade regular way on
         such exchange or in such market after the Expiration Time of such
         offer.

     Notwithstanding the foregoing, whenever successive adjustments to the
     Conversion Rate are called for pursuant to this Section 12.3, such
     adjustments shall be made to the Current Market Price as may be necessary
     or appropriate to effectuate the intent of this Section 12.3 and to avoid
     unjust or inequitable results as determined in good faith by the Board of
     Directors.

     "FAIR MARKET VALUE" means the amount which a willing buyer would pay a
     willing seller in an arm's length transaction (as determined by the Board
     of Directors, whose determination shall be made in good faith and, absent
     manifest error, shall be final and binding on Holders of the Securities).

     "RECORD DATE" means, with respect to any dividend, distribution or other
     transaction or event in which the holders of Common Stock have the right to
     receive any cash, securities or other property or in which the Common Stock
     (or other applicable security) is exchanged for or converted into any
     combination of cash, securities or other property, the date fixed for
     determination of stockholders entitled to receive such cash, securities or
     other property (whether such date is fixed by the Board of Directors or by
     statute, contract or otherwise).

(h)  The Company shall be entitled to make such additional adjustments in the
     Conversion Rate, in addition to those required by Section 12.3(a), Section
     12.3(b), Section 12.3(c), Section 12.3(d), Section 12.3(e) or Section
     12.3(f) if the Board of Directors determines that it is advisable, subject
     to compliance with Nasdaq Marketplace Rule 4350(i), in order that any
     dividend or distribution of Common Stock, any subdivision, reclassification
     or combination of Common Stock or any issuance of rights or warrants
     referred to above shall not be taxable to the holders of Common Stock for
     United States federal income tax purposes.

(i)  To the extent permitted by applicable law, the Company may, from time to
     time, increase the Conversion Rate by any amount for any period of time if
     such period is at least 20 calendar days, the increase is irrevocable

                                       48
<PAGE>

     during the period and the Board of Directors, in good faith and absent
     manifest error, determines that such increase would be in the best interest
     of the Company, subject to compliance with Nasdaq Marketplace Rule 4350(i).
     Whenever the Conversion Rate is increased pursuant to the preceding
     sentence, the Company shall mail to the Trustee and each Holder at the
     address of such Holder as it appears in the register of the Securities
     maintained by the Registrar, at least 15 calendar days prior to the date
     the increased Conversion Rate takes effect, a notice of the increase
     stating the increased Conversion Rate and the period during which it shall
     be in effect.

(j)  In any case in which this Section 12.3 shall require that any adjustment be
     made effective as of or retroactively immediately following a Record Date,
     the Company may elect to defer (but only for five Trading Days following
     the filing of the notice referred to in Section 12.5) issuing to the Holder
     of any Securities converted after such Record Date the Common Stock
     issuable upon such conversion over and above the Common Stock issuable upon
     such conversion on the basis of the Conversion Rate prior to adjustment;
     provided, however, that the Company shall deliver to such Holder a due bill
     or other appropriate instrument evidencing such Holder's right to receive
     such additional Common Stock upon the occurrence of the event requiring
     such adjustment.

(k)  All calculations under this Section 12.3 shall be made to the nearest cent
     or one-hundredth of a share, with one-half cent and 0.005 of a share,
     respectively, being rounded upward. Notwithstanding any other provision of
     this Section 12.3, the Company shall not be required to make any adjustment
     of the Conversion Rate unless such adjustment would require an increase or
     decrease of at least 1% in the Conversion Rate as last adjusted. Any lesser
     adjustment shall be carried forward and shall be made at the time of and
     together with the next subsequent adjustment which, together with any
     adjustment or adjustments so carried forward, shall amount to an increase
     or decrease of at least 1% in the Conversion Rate as last adjusted. Any
     adjustments under this Section 12.3 shall be made successively whenever an
     event requiring such an adjustment occurs.

(l)  In the event that at any time, as a result of an adjustment made pursuant
     to this Section 12.3, the Holder of any Securities thereafter surrendered
     for conversion shall become entitled to receive any shares of stock of the
     Company other than Common Stock into which the Securities originally were
     convertible, the Conversion Rate of such other shares so receivable upon
     conversion of any such Security shall be subject to adjustment from time to
     time in a manner and on terms as nearly equivalent as practicable to the
     provisions with respect to Common Stock contained in subparagraphs (a)
     through (j) of this Section 12.3, and the provision of Section 12.1,
     Section 12.2 and Section 12.4 through Section 12.9 with respect to the
     Common Stock shall apply on like or similar terms to any such other shares
     and the determination of the Board of Directors as to any such adjustment
     shall be conclusive.

(m)  No adjustment shall be made pursuant to this Section 12.3 if (i) the effect
     thereof would be to reduce the Conversion Price below the par value (if
     any) of the Common Stock or (ii) any dividend, distribution or issuance
     that would otherwise give rise to an adjustment pursuant to this Section
     12.3 is made or paid to the Holders of the Securities.

Section 12.4. Consolidation or Merger of the Company.

If any of the following events occurs, namely:

                  (a)      any reclassification or change of the outstanding
         shares of Common Stock (other than a change in par value, or from par
         value to no par value, or from no par value to par value, or as a
         result of a subdivision or combination);

                  (b)      any merger, consolidation, statutory share exchange
         or combination of the Company with another corporation as a result of
         which holders of Common Stock shall be entitled to receive stock,
         securities or other property or assets (including cash) with respect to
         or in exchange for such Common Stock; or

                                       49
<PAGE>

                  (c)      any sale or conveyance of the properties and assets
         of the Company as, or substantially as, an entirety to any other
         corporation as a result of which holders of Common Stock shall be
         entitled to receive stock, securities or other property or assets
         (including cash) with respect to or in exchange for such Common Stock;

the Company or the successor or purchasing corporation, as the case may be,
shall execute with the Trustee a supplemental indenture (which shall comply with
the Trust Indenture Act as in force at the date of execution of such
supplemental indenture, if such supplemental indenture is then required to so
comply) providing that such Securities shall be convertible into the kind and
amount of shares of stock and other securities or property or assets (including
cash) which such Holder would have been entitled to receive upon such
reclassification, change, merger, consolidation, statutory share exchange,
combination, sale or conveyance had such Securities been converted into Common
Stock immediately prior to such reclassification, change, merger, consolidation,
statutory share exchange, combination, sale or conveyance assuming such holder
of Common Stock did not exercise its rights of election, if any, as to the kind
or amount of securities, cash or other property receivable upon such merger,
consolidation, statutory share exchange, sale or conveyance (provided, that if
the kind or amount of securities, cash or other property receivable upon such
merger, consolidation, statutory share exchange, sale or conveyance is not the
same for each share of Common Stock in respect of which such rights of election
shall not have been exercised ("NON-ELECTING SHARE"), then for the purposes of
this Section 12.4, the kind and amount of securities, cash or other property
receivable upon such merger, consolidation, statutory share exchange, sale or
conveyance for 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
XII. If, in the case of any such reclassification, change, merger,
consolidation, statutory share exchange, combination, sale or conveyance, the
stock or other securities and assets receivable thereupon by a holder of Common
Stock includes shares of stock or other securities and assets of a corporation
other than the successor or purchasing corporation, as the case may be, in such
reclassification, change, merger, consolidation, statutory share exchange,
combination, sale or conveyance, then such supplemental indenture shall also be
executed by such other corporation 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
Company shall cause notice of the execution of such supplemental indenture to be
mailed to each Holder, at the address of such Holder as it appears on the
register of the Securities maintained by the Registrar, within 20 days after
execution thereof. Failure to deliver such notice shall not affect the legality
or validity of such supplemental indenture.

The above provisions of this Section 12.4 shall similarly apply to successive
reclassifications, mergers, consolidations, statutory share exchanges,
combinations, sales and conveyances.

If this Section 12.4 applies to any event or occurrence, Section 12.3 shall not
apply.

Section 12.5. Notice of Adjustment.

Whenever an adjustment in the Conversion Rate with respect to the Securities is
required:

                  (a)      the Company shall forthwith place on file with the
         Trustee and any Conversion Agent for such securities a certificate of
         the Chief Financial Officer of the Company, stating the adjusted
         Conversion Rate determined as provided herein and setting forth in
         reasonable detail such facts as shall be necessary to show the reason
         for and the manner of computing such adjustment; and

                  (b)      a notice stating that the Conversion Rate has been
         adjusted and setting forth the adjusted Conversion Rate shall forthwith
         be given by the Company or, at the Company's request, by the Trustee in
         the name and at the expense of the Company, to each Holder in the
         manner provided in Section 13.2. Any notice so given shall be
         conclusively presumed to have been duly given, whether or not the
         Holder receives such notice.

Section 12.6. Notice in Certain Events.

In case of:

                  (a)      a consolidation or merger to which the Company is a
         party and for which approval of any stockholders of the Company is
         required, or of the sale or conveyance to another Person or entity or
         group

                                       50
<PAGE>

         of Persons or entities acting in concert as a partnership, limited
         partnership, syndicate or other group (within the meaning of Rule 13d-3
         under the Exchange Act) of all or substantially all of the property and
         assets of the Company; or

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

                  (c)      any action triggering an adjustment of the Conversion
         Rate referred to in clauses (x) or (y) below;

then, in each case, the Company shall cause to be filed with the Trustee and the
Conversion Agent, and shall cause to be given, to the Holders of the Securities
in the manner provided in Section 13.2, at least 15 days prior to the applicable
date hereinafter specified, a notice stating:

                  (x)      the date on which a record is to be taken for the
         purpose of any distribution or grant of rights or warrants triggering
         an adjustment to the Conversion Rate pursuant to this Article XII, or,
         if a record is not to be taken, the date as of which the holders of
         record of Common Stock entitled to such distribution, rights or
         warrants are to be determined; or

                  (y)      the date on which any reclassification,
         consolidation, merger, sale, conveyance, dissolution, liquidation or
         winding up triggering an adjustment to the Conversion Rate pursuant to
         this Article XII is expected to become effective, and the date as of
         which it is expected that holders of Common Stock of record shall be
         entitled to exchange their shares of Common Stock for securities or
         other property deliverable upon such reclassification, consolidation,
         merger, sale, conveyance, dissolution, liquidation or winding up.

Failure to give such notice or any defect therein shall not affect the legality
or validity of the proceedings described in Section 12.6(a), Section 12.6(b) or
Section 12.6(c).

Section 12.7. Company To Reserve Stock: Registration; Listing.

(a)  The Company shall, prior to issuance of any Securities hereunder, and from
     time to time as may be necessary, reserve and keep available, free from
     preemptive rights, out of its authorized but unissued Common Stock, for the
     purpose of effecting the conversion of the Securities, such number of its
     duly authorized Common Stock as shall from time to time be sufficient to
     effect the conversion of all Securities then outstanding into such Common
     Stock at any time (assuming that, at the time of the computation of such
     number of Common Stock, all such Securities would be held by a single
     Holder). The Company covenants that all Common Stock which may be issued
     upon conversion of Securities shall upon issue be fully paid and
     nonassessable and free from all liens and charges and, except as provided
     in Section 12.8, taxes with respect to the issue thereof.

(b)  If any Common Stock which would be issuable upon conversion of Securities
     hereunder require registration with or approval of any governmental
     authority before such shares or securities may be issued upon such
     conversion, the Company shall use its reasonable best efforts to cause such
     shares or securities to be duly registered or approved, as the case may be.
     The Company further covenants that so long as the Common Stock shall be
     quoted on the Nasdaq National Market system, the Company shall use its
     reasonable best efforts, if permitted by the rules of the Nasdaq National
     Market system, to keep so quoted all Common Stock issuable upon conversion
     of the Securities, and the Company shall use its reasonable best efforts to
     list or obtain approval for the quotation of the Common Stock to be
     delivered upon conversion of the Securities prior to such delivery upon any
     other national securities exchange or quotation system upon which the
     outstanding Common Stock is listed or quoted at the time of such delivery.

Section 12.8. Taxes on Conversion.

The issue of stock certificates on conversion of Securities shall be made
without charge to the converting Holder for any documentary, stamp or similar
issue or transfer taxes in respect of the issue thereof, and the Company shall
pay any and all documentary, stamp or similar issue or transfer taxes that may
be payable in respect of the issue or delivery of Common Stock on conversion of
Securities pursuant hereto. The Company shall not, however, be required to pay
any such tax which may be payable in respect of any transfer involved in the
issue or delivery of Common Stock or the portion, if any, of the Securities
which

                                       51
<PAGE>

are not so converted in a name other than that in which the Securities so
converted were registered, and no such issue or delivery shall be made unless
and until the Person requesting such issue has paid to the Company the amount of
such tax or has established to the satisfaction of the Company that such tax has
been paid.

Section 12.9. Conversion After Regular Record Date.

Except as provided in the succeeding paragraph, the Holder of Securities shall
not be entitled to receive any accrued and unpaid interest or Additional
Interest, if any.

If any Securities are surrendered for conversion subsequent to the close of
business on any Regular Record Date but prior to the opening of business on the
corresponding Interest Payment Date, the Holder of such Securities at the close
of business on such Regular Record Date shall receive the interest and
Additional Interest, if any, payable on such Securities on such Interest Payment
Date notwithstanding the conversion thereof. Securities surrendered for
conversion during the period from the close of business on any Regular Record
Date to the opening of business on the corresponding Interest Payment Date shall
(except in the case of Securities which have been called for redemption on a
Redemption Date within such period) be accompanied by payment by Holders, for
the account of the Company, in New York Clearing House funds or other funds
acceptable to the Company of an amount equal to the interest and Additional
Interest, if any, payable on such interest payment date on the Securities being
surrendered for conversion.

Except as provided in Section 12.2(a) and this Section 12.9, no payment or
adjustment shall be made in respect of dividends or distributions on the Common
Stock issued upon conversion or accrued and unpaid interest or Additional
Interest, if any, on a converted Security.

Section 12.10. Company Determination Final.

Any determination that the Company or the Board of Directors must make pursuant
to this Article XII shall be conclusive if made in good faith and in accordance
with the provisions of this Article, absent manifest error, and set forth in a
Board Resolution.

Section 12.11. Responsibility of Trustee for Conversion Provisions.

The Trustee has no duty to determine when an adjustment under this Article XII
should be made, how it should be made or what it should be. The Trustee makes no
representation as to the validity or value of any securities or assets issued
upon conversion of Securities. The Trustee shall not be responsible for any
failure of the Company to comply with this Article XII. Each Conversion Agent
other than the Company shall have the same protection under this Section 12.11
as the Trustee.

The rights, privileges, protections, immunities and benefits given to the
Trustee under this Indenture including, without limitation, its rights to be
indemnified, are extended to, and shall be enforceable by, other than the
Company, the Trustee in each of its capacities hereunder, and each Paying Agent
or Conversion Agent, other than the Company, acting hereunder.

Section 12.12. Unconditional Right of Holders to Convert.

Notwithstanding any other provision in this Indenture, the Holder of any
Security shall have the right, which is absolute and unconditional, to convert
its Security in accordance with this Article XII and to bring an action against
the Company for the enforcement of any such right to convert, and such rights
shall not be impaired or affected without the consent of such Holder.

Section 12.13. Option to Satisfy Conversion Obligation with Cash, Common Stock
or Combination Thereof.

(a)  If the Company receives any Holder's Conversion Notice on or prior to the
     day that is 31 Trading Days prior to the Stated Maturity (the "FINAL NOTICE
     DATE"), then the Company shall notify the Holder through the Trustee, at
     any time on or before the date that is three Trading Days following receipt
     of the Conversion Notice required pursuant to Section 12.2 (such period,
     the "SETTLEMENT NOTICE PERIOD") of the method the Company chooses to settle
     its obligation upon conversion (the "CONVERSION OBLIGATION"). If the
     Company elects to settle its Conversion Obligation in a combination of cash
     and Common Stock, the Company shall specify both the percentage of the
     principal amount of Securities surrendered for conversion that it will pay
     in cash and the percentage of the excess (the "EXCESS AMOUNT"), if any, of
     the Conversion Obligation relating to the Securities surrendered for
     conversion over the principal amount of the Securities surrendered for
     conversion that it will pay

                                       52
<PAGE>

     in cash. The remainder of its Conversion Obligation will be settled in
     shares of Common Stock (except that cash will be paid in lieu of issuing
     any fractional shares). The Company shall treat all Holders converting on
     the same Trading Day in the same manner and the Company shall not have any
     obligation to settle Conversion Obligations arising on different Trading
     Days in the same manner.

                  If the Company timely elects to pay cash for any portion of
the Conversion Obligation, the Holder may retract the Conversion Notice at any
time during the two Trading Day period beginning on the Trading Day after the
Settlement Notice Period (the "CONVERSION RETRACTION PERIOD"); provided, that no
such retraction can be made (and a Conversion Notice shall be irrevocable) if
the Company does not elect to deliver cash in lieu of shares (other than cash in
lieu of fractional shares). Settlement in Common Stock only will occur in
accordance with Section 12.2(a). If the Conversion Notice has not been
retracted, then settlement in cash or in a combination of cash and Common Stock
will, subject to Section 12.13(c), occur on the third Trading Day following the
final Trading Day of the 20 Trading Day period beginning on the third Trading
Day following the final Trading Day of the Conversion Retraction Period (the
"CASH SETTLEMENT AVERAGING PERIOD"), assuming all of the other requirements have
been satisfied by such Holder.

                  Settlement amounts will be computed as follows (subject to the
provisions of the third paragraph of Section 12.1(a) in connection with
conversions during a Registration Default Period):

                           (i)      if the Company elects to satisfy the entire
         Conversion Obligation in Common Stock, the Company shall deliver to
         such Holder a number of shares of Common Stock equal to (1) the
         aggregate original principal amount of Securities to be converted
         divided by 1,000, multiplied by (2) the Conversion Rate;

                           (ii)     if the Company elects to satisfy the Entire
         Conversion Obligation in cash, the Company shall deliver to such Holder
         cash in an amount equal to the product of:

                                    (1)      a number equal to (x) the aggregate
                  original principal amount of Securities to be converted
                  divided by 1,000, multiplied by (y) the Conversion Rate, and

                                    (2)      the arithmetic average of the
                  Closing Prices of Common Stock during the Cash Settlement
                  Averaging Period; and

                           (iii)    if the Company elects to satisfy a portion
         of the Conversion Obligation in cash (the "CASH AMOUNT") (excluding any
         cash paid for fractional shares) and a portion of the Conversion
         Obligation in Common Stock, the Company shall deliver to such Holder:

                                    (1)      the Cash Amount equal to the
                  aggregate principal amount of Securities to be converted
                  multiplied by the percentage of such principal amount to be
                  satisfied in cash, and if greater than zero, the product of
                  (x) the amount of cash that would be paid pursuant to clause
                  (ii) above minus the aggregate principal amount of the
                  Securities surrendered for conversion, and (y) the percentage
                  of the Excess Amount to be satisfied in cash; plus

                                    (2)      the number of shares of Common
                  Stock equal to (x) the number of shares of Common Stock that
                  would be issued pursuant to clause (i) above minus (y) the
                  number of shares of Common Stock equal to the quotient of the
                  Cash Amount divided by the arithmetic average of the Closing
                  Sale Prices of the Common Stock during the Cash Settlement
                  Averaging Period.

Notwithstanding the foregoing, a Security in respect of which a Holder has
delivered a Designated Event Purchase Notice exercising such Holder's right to
require the Company to repurchase such Security may be converted as described in
this Section 12.13(a) only if such notice of exercise is withdrawn in accordance
with Section 4.2(b) prior to 5:00 p.m., New York City time, on the Business Day
immediately preceding the Designated Event Purchase Date.

                                       53
<PAGE>

(b)  The Company shall settle all of its Conversion Obligations arising after
     the Final Notice Date in the same manner. On or prior to the Final Notice
     Date, the Company shall notify the Holders through the Trustee of the
     method it chooses to settle any Conversion Obligations arising after the
     Final Notice Date. If the Company elects to settle any Conversion
     Obligations arising after the Final Notice Date in a combination of cash
     and Common Stock, the Company shall specify both the percentage of the
     principal amount of Securities surrendered for conversion that it will pay
     in cash and the percentage of the Excess Amount that it will pay in cash.
     The remainder of any Conversion Obligation arising after the Final Notice
     Date shall be settled in shares of Common Stock (except that cash will be
     paid in lieu of issuing any fractional shares). All Conversion Notices
     received after the Final Notice Date shall be irrevocable.

                  (c) Settlement of Conversion Obligations arising after the
Final Notice Date in Common Stock shall occur in accordance with Section
12.2(a). Settlement of Conversion Obligations arising after the Final Notice
Date in cash or in a combination of cash and Common Stock shall occur on the
third Trading Day following the final Trading Day of the Cash Settlement
Averaging Period described in the following sentence. The settlement amount of
Common Stock, cash or combination of cash and Common Stock in satisfaction of
Conversion Obligations arising after the Final Notice Date shall be computed in
the same manner as set forth in Section 12.31(a), except that the "Cash
Settlement Averaging Period" shall be the 20 Trading Day period beginning on the
date that is the 23rd Trading Day prior to the Stated Maturity.

                                  ARTICLE XIII

                                  MISCELLANEOUS

Section 13.1. Trust Indenture Act Controls. If any provision of this Indenture
     limits, qualifies, or conflicts with the duties imposed by Section 318(c)
     of the TIA, such section of the TIA shall control. If any provision of this
     Indenture expressly modifies or excludes any provision of the TIA that may
     be so modified or excluded, the Indenture provision so modifying or
     excluding such provision of the TIA shall be deemed to apply.

Section 13.2. Notices. Any request, demand, authorization, notice, waiver,
     consent or communication shall be in writing and delivered in person
     (including by commercial courier services) or mailed by first-class mail,
     postage prepaid, addressed as follows or transmitted by facsimile
     transmission (confirmed by guaranteed overnight courier) to the following
     facsimile numbers:

     if to the Company:
     CONCORD COMMUNICATIONS, INC.
     400 Nickerson Road
     Marlboro, Massachusetts 01752
     Attention: Chief Financial Officer
     Facsimile No.: (508) 481-9772
     with a copy to:
     TESTA, HURWITZ & THIBEAULT, LLP
     125 High Street
     Boston, Massachusetts 02110
     Attention:  Kevin M. Barry, Esq.
     Facsimile No.: (617) 248-7100

     if to the Trustee:
     WILMINGTON TRUST COMPANY
     1100 North Market Street, Rodney Square North
     Wilmington, DE 19890-1615
     Attention: Corporate Capital Markets
     Facsimile No.: (302) 636-4145

The Company or the Trustee by notice given to the other in the manner provided
above may designate additional or different addresses for subsequent notices or
communications.

                                       54
<PAGE>

Any notice or communication given to a Holder shall be mailed to
the Holder, by first-class mail, postage prepaid, at the Holder's address as it
appears on the registration books of the Registrar and shall be sufficiently
given if so mailed within the time prescribed.

Failure to mail a notice or communication to a Holder or any defect in it shall
not affect its sufficiency with respect to other Holders. If a notice or
communication is mailed in the manner provided above, it is duly given, whether
or not received by the addressee.

If the Company mails a notice or communication to the Holders, it shall mail a
copy to the Trustee and each Registrar, Paying Agent, Conversion Agent, or
co-registrar.

Section 13.3. Communication by Holders with Other Holders.

Holders may communicate pursuant to Section 312(b) of the TIA with other Holders
with respect to their rights under this Indenture or the Securities. The
Company, the Trustee, the Registrar, the Paying Agent, the Conversion Agent and
anyone else shall have the protection of TIA Section 312(c).

Section 13.4.     Certificate and Opinion as to Conditions Precedent.

Upon any request or application by the Company to the Trustee to take any action
under this Indenture (except in connection with the original issuance of
Securities), the Company shall furnish to the Trustee:

                  (a)      an Officers' Certificate stating that, in the opinion
         of the signers, all conditions precedent, if any, provided for in this
         Indenture relating to the proposed action have been complied with; and

                  (b)      an Opinion of Counsel stating that, in the opinion of
         such counsel, all such conditions precedent have been complied with.

Section 13.5. Statements Required in Certificate or Opinion.

Each Officers' Certificate or Opinion of Counsel with respect to compliance with
a covenant or condition provided for in this Indenture shall include:

                  (a)      a statement that each person making such Officers'
         Certificate or Opinion of Counsel has read such covenant or condition;

                  (b)      a brief statement as to the nature and scope of the
         examination or investigation upon which the statements or opinions
         contained in such Officers' Certificate or Opinion of Counsel are
         based;

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

                  (d)      a statement that, in the opinion of such person, such
         covenant or condition has been complied with.

In giving such Opinion of Counsel, counsel may rely as to factual matters on an
Officer's Certificate or on certificates of public officials.

Section 13.6. Separability Clause.

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

Section 13.7. Rules by Trustee, Paying Agent, Conversion Agent, Registrar.

The Trustee may make reasonable rules for action by or a meeting of Holders. The
Registrar, the Conversion Agent and the Paying Agent may make reasonable rules
for their functions.

                                       55
<PAGE>

Section 13.8. Legal Holidays.

If any specified date (including a date for giving notice) is a Legal Holiday,
the action shall be taken on the next succeeding day that is not a Legal
Holiday, and, if the action to be taken on such date is a payment in respect of
the Securities, no interest, if any, shall accrue for the intervening period.

Section 13.9. Governing Law; Submission to Jurisdiction; Service of Process.

This Indenture shall be governed by, and construed in accordance with, the laws
of the State of New York. The Company submits to the non-exclusive jurisdiction
of the courts of the State of New York and the courts of the United States of
America, in each case located in the Borough of Manhattan, New York, New York
over any suit, action or proceeding arising under or in connection with this
Indenture or the transactions contemplated hereby or the Securities. The Company
waives any objection that it may have to the venue of any suit, action or
proceeding arising under or in connection with this Indenture or the
transactions contemplated hereby or the Securities in the courts of the State of
New York or the courts of the United States of America, in each case located in
the Borough of Manhattan, New York, New York, or that such suit, action or
proceeding brought in the courts of the State of New York or the courts of the
United States of America, in each case located in the Borough of Manhattan, New
York, New York, was brought in an inconvenient court and agrees not to plead or
claim the same.

The Company agrees that service of all writs, process and summonses in any suit,
action or proceeding arising under or in connection with this Indenture or the
transactions contemplated thereby or the Securities against the Company in any
court of the State of New York or any United States Federal court, in each case,
sitting in the Borough of Manhattan, New York, New York, may be made upon CT
Corporation System at 111 Eighth Avenue, New York, New York 10011, whom the
Company irrevocably appoints as its authorized agent for service of process. The
Company represents and warrants that CT Corporation System has agreed to act as
the Company's agent for service of process. The Company agrees that such
appointment shall be irrevocable until the irrevocable appointment by the
Company of a successor in New York, New York as its authorized agent for such
purpose and the acceptance of such appointment by such successor. The Company
further agrees to take any and all action, including the filing of any and all
documents and instruments that may be necessary to continue such appointment in
full force and effect as aforesaid. If CT Corporation System shall cease to act
as the agent for service of process for the Company, the Company shall appoint
without delay, another such agent and provide prompt written notice to the
Trustee of such appointment.

Section 13.10. No Recourse Against Others.

No recourse under or upon any obligation, covenant or agreement contained in
this Indenture, or in any Security, or because of any indebtedness evidenced
thereby, shall be had against any incorporator, as such, or against any past,
present or future stockholder, officer or director, as such, of the Company or
of any successor, either directly or through the Company or any successor, under
any rule of law, statute or constitutional provision or by the enforcement of
any assessment or by any legal or equitable proceeding or otherwise, all such
liability being expressly waived and released by the acceptance of the
Securities by the Holders and as part of the consideration for the issue of the
Securities.

Section 13.11. Successors.

All agreements of the Company in this Indenture and the Securities shall bind
its successor. All agreements of the Trustee in this Indenture shall bind its
successor.

Section 13.12. Multiple Originals.

The parties may sign any number of copies of this Indenture. Each signed copy
shall be an original, but all of them together represent the same agreement. One
signed copy is enough to prove this Indenture.

                                     * * * *
            [THE REMAINDER OF THIS PAGE IS INTENTIONALLY LEFT BLANK]

                                       56
<PAGE>

IN WITNESS WHEREOF, the undersigned, being duly authorized, have executed this
Indenture on behalf of the respective parties hereto as of the date first above
written.

                               CONCORD COMMUNICATIONS, INC.

                               By: /s/ Melissa H. Cruz
                                   ---------------------------
                               Name: Melissa H. Cruz
                               Title: Executive Vice President
                                      of Business Services,
                                      Chief Financial Officer
                                      and Treasurer

                           SIGNATURE PAGE TO INDENTURE

<PAGE>

                               WILMINGTON TRUST COMPANY
                               As Trustee

                               By: /s/ James J. McGinley
                                   ---------------------------
                               Name: James J. McGinley
                               Title: Authorized Signer

                           SIGNATURE PAGE TO INDENTURE

<PAGE>

                                    EXHIBIT A

                           [FORM OF FACE OF SECURITY]

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE ISSUER OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (AND ANY PAYMENT HEREON IS MADE
TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY), ANY TRANSFER, PLEDGE OR OTHER
USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE
REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN. 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 IS
EXCHANGEABLE FOR SECURITIES REGISTERED IN THE NAME OF A PERSON OTHER THAN THE
DEPOSITARY OR ITS NOMINEE ONLY IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE
INDENTURE AND, UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR
SECURITIES IN DEFINITIVE FORM, THIS SECURITY MAY NOT BE TRANSFERRED EXCEPT AS A
WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE
DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE
DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY.]

[THE SECURITY EVIDENCED BY THIS CERTIFICATE HAS NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT OF 1933"), OR ANY STATE
SECURITIES LAWS, AND MAY NOT BE OFFERED OR SOLD EXCEPT AS SET FORTH IN THE
FOLLOWING SENTENCE. BY ACQUISITION HEREOF, THE HOLDER:

                  (1)      REPRESENTS THAT IT IS (A) A "QUALIFIED INSTITUTIONAL
         BUYER" AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT OF 1933 OR (B)
         IT IS AN INSTITUTIONAL INVESTOR THAT IS AN "ACCREDITED INVESTOR" AS
         DEFINED IN RULE 501(A)(1), (2), (3) OR (7) UNDER THE SECURITIES ACT OF
         1933 (AN "INSTITUTIONAL ACCREDITED INVESTOR");

                  (2)      AGREES THAT IT SHALL NOT WITHIN TWO YEARS AFTER THE
         ORIGINAL ISSUANCE OF THIS SECURITY, RESELL OR OTHERWISE TRANSFER THE
         SECURITY EVIDENCED HEREBY OR THE SHARES OF COMMON STOCK ISSUABLE UPON
         CONVERSION OF SUCH SECURITY EXCEPT (A) TO THE COMPANY OR ANY SUBSIDIARY
         THEREOF, (B) TO A PERSON THAT THE HOLDER REASONABLY BELIEVES IS A
         "QUALIFIED INSTITUTIONAL BUYER" AS DEFINED IN, AND IN COMPLIANCE WITH,
         RULE 144A UNDER THE SECURITIES ACT OF 1933, (C) PURSUANT TO THE
         EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES
         ACT OF 1933 (IF AVAILABLE), (D) PURSUANT TO AN EXEMPTION FROM THE
         REGISTRATION REQUIREMENTS OF THE SECURITIES ACT OF 1933 (IF AVAILABLE)
         TO AN INSTITUTIONAL ACCREDITED INVESTOR THAT, PRIOR TO SUCH TRANSFER,
         FURNISHES TO AMERICAN STOCK TRANSFER AND TRUST COMPANY, AS TRANSFER
         AGENT (OR ANY SUCCESSOR TRANSFER AGENT, AS APPLICABLE), SUCH
         CERTIFICATIONS AND OPINION OF COUNSEL REQUIRED BY THE COMPANY OR THE
         TRANSFER AGENT OR (E) PURSUANT TO A REGISTRATION STATEMENT THAT HAS
         BEEN DECLARED EFFECTIVE UNDER THE SECURITIES ACT OF 1933 AND THAT
         CONTINUES TO BE EFFECTIVE AT THE TIME OF SUCH TRANSFER; AND

                  (3)      AGREES THAT IT WILL DELIVER TO EACH PERSON TO WHOM
         THE SECURITY EVIDENCED HEREBY IS TRANSFERRED (OTHER THAN A TRANSFER
         PURSUANT TO CLAUSE 2(C) OR 2(E) ABOVE), A NOTICE SUBSTANTIALLY TO THE
         EFFECT OF THIS LEGEND.] (1)

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

(1) This legend should be included only if the Security is a Transfer Restricted
Security.

                                      A-1

<PAGE>

[THE HOLDER OF THIS SECURITY IS ENTITLED TO THE BENEFITS OF A REGISTRATION
RIGHTS AGREEMENT (AS SUCH TERM IS DEFINED IN THE INDENTURE REFERRED TO ON THE
REVERSE HEREOF) AND, BY ITS ACCEPTANCE HEREOF, AGREES TO BE BOUND BY AND TO
COMPLY WITH THE PROVISIONS OF SUCH REGISTRATION RIGHTS AGREEMENT.](1)

                                      A-2

<PAGE>

                          CONCORD COMMUNICATIONS, INC.
                     3.0% CONVERTIBLE SENIOR NOTES DUE 2023

No. ___ CUSIP: 206 186 AA6

CONCORD COMMUNICATIONS, INC., a Massachusetts corporation (the "Company", which
term shall include any successor corporation under the Indenture referred to on
the reverse hereof) promises to pay to _____________________, or registered
assigns, the principal amount of _______________ Dollars ($_________) [, or such
greater or lesser amount as is indicated in the records of the Trustee and the
Depositary,] on December 15, 2023, and to pay interest thereon from December 8,
2003 or from the most recent Interest Payment Date to which interest has been
paid or duly provided for, on June 15 and December 15 in each year (each, an
"INTEREST PAYMENT DATE"), commencing on June 15, 2004, at the rate of 3.0% per
annum, until the principal hereof is paid or made available for payment at
December 15, 2023 or upon acceleration, or until such date on which the
Securities are converted, redeemed or purchased as provided herein, and at the
rate of 3.0% per annum on any overdue principal and on any overdue installment
of interest and Additional Interest, if any. The interest so payable, and
punctually paid or duly provided for, on any Interest Payment Date shall, as
provided in the Indenture (as hereinafter defined), be paid to the Person in
whose name this Security (or one or more predecessor Securities) is registered
at the close of business on the regular record date for such interest, which
shall be the June 1 or December 1 (whether or not a Business Day), as the case
may be, next preceding the corresponding Interest Payment Date (a "REGULAR
RECORD DATE"). Any such interest Additional Interest, if any, not so punctually
paid or duly provided for shall forthwith cease to be payable to the Holder on
such Regular Record Date and may be paid (a) 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 (a "SPECIAL RECORD DATE"), notice whereof shall be given
to Holders not less than 10 calendar days prior to such Special Record Date, or
(b) at any time in any other lawful manner not inconsistent with the
requirements of any securities exchange on which the Securities may be listed,
and upon such notice as may be required by such exchange, all as more fully
provided in the Indenture. Reference is hereby made to the further provisions of
this Security set forth on the reverse side of this Security, which further
provisions shall for all purposes have the same effect as if set forth at this
place.

                                      A-3

<PAGE>

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

Dated: CONCORD COMMUNICATIONS, INC.

                               By: -

                               Name:______________________________

                               Title:_____________________________

                                      A-4

<PAGE>

                     TRUSTEE'S CERTIFICATE OF AUTHENTICATION

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

Dated: WILMINGTON TRUST COMPANY,
                                as Trustee

                                By: _

                                      A-5

<PAGE>

                          [FORM OF REVERSE OF SECURITY]
                     3.0% CONVERTIBLE SENIOR NOTES DUE 2023

This Security is one of a duly authorized issue of 3.0% Convertible Senior Notes
due 2023 (the "Securities") of CONCORD COMMUNICATIONS, INC., a Massachusetts
corporation (including any successor corporation under the Indenture hereinafter
referred to, the "Company"), issued under an Indenture, dated as of December 8,
2003 (the "Indenture"), between the Company and WILMINGTON TRUST COMPANY, a
Delaware banking corporation, as Trustee (the "Trustee"). The terms of the
Security include those stated in the Indenture, those made part of the Indenture
by reference to the Trust Indenture Act of 1939, as amended ("TIA"), and those
set forth in this Security. This Security is subject to all such terms, and
Holders are referred to the Indenture and the TIA for a statement of all such
terms. To the extent permitted by applicable law, in the event of any
inconsistency between the terms of this Security and the terms of the Indenture,
the terms of the Indenture shall control. Capitalized terms used but not defined
herein have the meanings assigned to them in the Indenture referred to below
unless otherwise indicated.

1. Interest.

Interest on the Securities shall be computed on the basis of a 360-day year of
twelve 30-day months. If this Security is redeemed pursuant to Section 5 of this
Security or the Holder elects to require the Company to purchase this Security
pursuant to Section 6 of this Security, on a date that is after the Regular
Record Date and on or before the corresponding Interest Payment Date, interest
and Additional Interest, if any, accrued and unpaid hereon to, but excluding,
the applicable Redemption Date, Purchase Date or Designated Event Purchase Date
shall be paid to the same Holder to whom the Company pays the principal of this
Security.

Interest and Additional Interest, if any, on Securities converted after the
close of business on a Regular Record Date but prior to the opening of business
on the corresponding Interest Payment Date shall be paid to the Holder of the
Securities on the Regular Record Date but, upon conversion, the Holder must pay
the Company the interest and Additional Interest, if any, which has accrued and
shall be paid on such Interest Payment Date. No such payment need be made with
respect to Securities which shall be converted after a Regular Record Date and
prior to the corresponding Interest Payment Date after being called for
redemption.

Any reference herein to interest accrued or payable as of any date shall include
any Additional Interest accrued or payable on such date as provided in the
Registration Rights Agreement.

2. Method of Payment.

Payment of the principal of and interest and Additional Interest, if any, on the
Securities shall be 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
or in Applicable Stock, as the case may be. The Holder must surrender the
Securities to the Paying Agent to collect payment of principal. Payment of
interest and Additional Interest, if any, on Certificated Securities shall be
made by check mailed to the address of the Person entitled thereto as such
address appears in the Register and payment of interest and Additional Interest,
if any, on Certificated Securities in aggregate principal amount in excess of
$5,000,000 shall be made by wire transfer in immediately available funds at the
election of such Holder. Notwithstanding the foregoing, so long as the
Securities are registered in the name of a Depositary or its nominee, all
payments with respect to the Securities shall be made by wire transfer of
immediately available funds to the account of the Depositary or its nominee.

3. Paying Agent, Registrar, Conversion Agent.

Initially, Wilmington Trust Company shall act as Paying Agent, Registrar and
Conversion Agent. The Company may appoint and change any Paying Agent, Registrar
and Conversion Agent without notice, other than notice to the Trustee; provided
that the Company shall maintain at least one Paying Agent in Borough of
Manhattan, New York, New York, which shall initially be an office or agency of
the Trustee. The Company or any of its Subsidiaries or any of their Affiliates
may act as Paying Agent, Registrar or Conversion Agent.

4. Indenture.

The Securities are general unsecured obligations of the Company limited to up to
$86,250,000 aggregate

                                      A-6

<PAGE>

principal amount. The Indenture does not limit other indebtedness of the
Company, secured or unsecured.

5. Redemption of the Notes by the Company.

The Securities are redeemable for cash at the option of the Company, in whole or
in part, at any time or from time to time on, or after December 15, 2008 upon
not less than 20 calendar days', nor more than 60 calendar days', notice by mail
for a redemption price equal to the principal amount of those Securities plus
accrued and unpaid interest and Additional Interest, if any, on those
Securities, to, but excluding, the Redemption Date.

Notice of redemption pursuant to this Section of this Security shall be mailed
at least 20 calendar days but not more than 60 calendar days before the
Redemption Date to each Holder of Securities to be redeemed at the Holder's
registered address. If cash sufficient to pay the Redemption Price of all
Securities (or portions thereof) to be redeemed on the Redemption Date is
deposited with the Paying Agent prior to 10:00 a.m., New York City time, on the
Redemption Date, then, on such Redemption Date interest and Additional Interest,
if any ceases to accrue on such Securities or portions thereof. Securities in
denominations larger than $1,000 of principal amount may be redeemed in part but
only in integral multiples of $1,000 of principal amount.

6. Purchase by the Company at the Option of the Holder or Upon a Designated
Event.

Subject to the terms and conditions of the Indenture, the Company shall become
obligated to purchase, at the option of the Holder, all or any portion of the
Securities held by such Holder on December 15, 2008, December 15, 2013 and
December 15, 2018 in integral multiples of $1,000 at the Purchase Price in cash.
To exercise such right, a Holder shall deliver to the Paying Agent a Purchase
Notice containing the information set forth in the Indenture, at any time from
the opening of business on the date that is 22 Business Days prior to the
relevant Purchase Date until the close of business on the second Business Day
prior to such Purchase Date, and shall deliver the Securities to the Paying
Agent as set forth in the Indenture.

Subject to the terms and conditions of the Indenture, the Company shall become
obligated to purchase, at the option of the Holder, all or any portion of the
Securities held by such Holder upon a Designated Event in integral multiples of
$1,000 at the Designated Event Purchase Price in cash. To exercise such right, a
Holder shall deliver to the Paying Agent a Designated Event Purchase Notice
containing the information set forth in the Indenture at any time on or before
the 20th Business Day after the date of the Company's notice of the Designated
Event (subject to extension to comply with applicable law), and shall deliver
the Securities to the Paying Agent as set forth in the Indenture.

Holders have the right to withdraw any Purchase Notice or Designated Event
Purchase Notice by delivering to the Paying Agent a written notice of withdrawal
in accordance with the provisions of the Indenture.

If cash sufficient to pay the Purchase Price or Designated Event Purchase Price,
as the case may be, of all Securities or portions thereof to be purchased on the
Purchase Date or the Designated Event Purchase Date, as the case may be, is
deposited with the Paying Agent, at 10:00 a.m., New York City time, on the
Purchase Date or the Designated Event Purchase Date, as the case may be, such
Securities shall cease to be outstanding and interest and Additional Interest,
if any, on such Securities shall cease to accrue and the Holder thereof shall
have no other rights as such other than the right to receive the Purchase Price
or Designated Event Purchase Price upon surrender of such Security.

7. Conversion.

Subject to and in compliance with the provisions of the Indenture (including,
without limitation, the conditions to conversion of this Security set forth in
Section 12.1 thereof), a Holder is entitled, at such Holder's option, to convert
the Holder's Security (or any portion of the principal amount thereof that is
$1,000 or an integral multiple $1,000), into fully paid and nonassessable shares
of Common Stock at the Conversion Rate in effect on the date of conversion.

Upon conversion, the Company shall have the right to deliver, in lieu of shares
of Common Stock, cash or a combination of cash and shares of Common Stock. If
the Company elects to pay cash in lieu of shares, the payment amount shall be
the product of (1) a number equal to (x) the aggregate original principal amount
of Securities to be converted divided by 1,000, multiplied by (y) the Conversion
Rate, and (2) the arithmetic average of the Closing Prices of Common Stock
during the Cash Settlement Averaging Period.

                                      A-7

<PAGE>

Until the Securities are surrendered for conversion, the Company shall not be
required to notify Holders of its method for settling the excess amount of its
conversion obligation of the $1,000 principal amount of the Securities.

The Company shall notify Holders of any event triggering the right to convert
the Securities as specified above in accordance with the Indenture.

A Security in respect of which a Holder has delivered a Purchase Notice or
Designated Event Purchase Notice, as the case may be, exercising the right of
such Holder to require the Company to purchase such Security may be converted
only if such Purchase Notice or Designated Event Purchase Notice is withdrawn in
accordance with the terms of the Indenture.

The initial Conversion Rate is 37.2148 shares of Common Stock per $1,000
principal amount of this Security, subject to adjustment in certain events
described in the Indenture. This reflects an initial Conversion Price of
approximately $26.87 per share.

To surrender a Security for conversion, a Holder must, in the case of Global
Securities, comply with the Applicable Procedures of the Depositary in effect at
that time, and in the case of Certificated Securities, (1) surrender the
Security to the Conversion Agent, (2) complete and manually sign the conversion
notice below (or complete and manually sign a facsimile of such notice) and
deliver such notice to the Conversion Agent, (3) if required by the Conversion
Agent, furnish appropriate endorsements and transfer documents and (4) pay all
funds required, if any, relating to interest or Additional Interest, if any, and
any transfer or similar tax or duty, if required.

No fractional share of Common Stock shall be issued upon conversion of any
Security. Instead, the Company shall pay a cash adjustment as provided in the
Indenture.

No payment or adjustment shall be made for accrued and unpaid interest and
Additional Interest, if any, or dividends on the Common Stock, except as
provided in the Indenture.

If the Company (i) is a party to a consolidation, merger or binding share
exchange (ii) reclassifies the Common Stock or (iii) conveys, transfers or
leases its properties and assets substantially as an entirety to any Person, the
right to convert a Security into shares of Common Stock may be changed into a
right to convert it into securities, cash or other assets of the Company or such
other Person, in each case in accordance with the Indenture.

8. Denominations; Transfer; Exchange.

The Securities are in fully registered form, without coupons, in denominations
of $1,000 of principal amount and integral multiples of $1,000. A Holder may
transfer or exchange Securities in accordance with the Indenture. The Registrar
may require a Holder, among other things, to furnish appropriate endorsements
and transfer documents and to pay any taxes and fees required by law or
permitted by the Indenture. The Registrar need not transfer or exchange any
Securities selected for redemption (except, in the case of a Security to be
redeemed in part, the portion of the Security not to be redeemed) or any
Securities in respect of which a Purchase Notice or Designated Event Purchase
Notice has been given and not withdrawn (except, in the case of a Security to be
purchased in part, the portion of the Security not to be purchased) or any
Securities for a period of 15 days before the mailing of a notice of redemption
of Securities to be redeemed.

9. Persons Deemed Owners.

The registered Holder of this Security may be treated as the owner of this
Security for all purposes.

10. Unclaimed Money or Securities.

The Trustee and the Paying Agent shall return to the Company upon written
request any cash or securities held by them for the payment of any amount with
respect to the Securities that remains unclaimed for two years, subject to
applicable unclaimed property law. After return to the Company, Holders entitled
to the money or securities must look to the Company for payment as general
creditors unless an applicable abandoned property law designates another person.

11. Amendment; Waiver.

Subject to certain exceptions set forth in the Indenture, (i) the Indenture or
the Securities may be amended with the written consent or affirmative vote of
the Holders of at least a majority in aggregate principal amount of the
outstanding Securities and (ii) certain Defaults may be waived with the written
consent or affirmative vote of the Holders of a majority in aggregate principal
amount of the outstanding Securities.

                                      A-8

<PAGE>

Without the consent of any Holder, the Company and the Trustee may amend the
Indenture or the Securities to (i) add to the covenants of the Company for the
benefit of the Holders of Securities, (ii) surrender any right or power
conferred upon the Company in the Indenture, (iii) provide for conversion rights
of Holders of Securities if any reclassification or change of the Company's
Common Stock or any consolidation, merger or sale of all or substantially all of
the Company's assets occurs, (iv) provide for the assumption of the Company's
obligations to the Holders of Securities in the case of a merger, consolidation,
conveyance, transfer, sale, lease or other disposition pursuant to Article VII
of the Indenture, (v) increase the Conversion Rate; provided, however, that such
increase in the Conversion Rate shall not adversely affect the interest of the
Holders of Securities (after taking into account tax and other consequences of
such increase), (vi) comply with the requirements of the SEC in order to effect
or maintain the qualification of the Indenture under the TIA, (vii) make any
changes or modifications necessary in connection with the registration of the
Securities under the Securities Act as contemplated in the Registration Rights
Agreement; provided, however, that such action pursuant to this clause does not,
in the good faith opinion of the Board of Directors of the Company (as evidenced
by a Board Resolution) and the Trustee, adversely affect the interests of the
Holders of Securities in any material respect, (viii) cure any ambiguity,
correct or supplement any provision in the Indenture which may be inconsistent
with any other provision therein or which is otherwise defective, or to make any
other provisions with respect to matters or questions arising under the
Indenture which the Company may deem necessary or desirable and which shall not
be inconsistent with the provisions of the Indenture; provided, however, that
such action pursuant to this clause does not, in the good faith opinion of the
Board of Directors of the Company (as evidenced by a Board Resolution) and the
Trustee, adversely affect the interests of the Holders of Securities in any
material respect, (ix) to evidence the succession of another Person to the
Company or any other obligor upon the Securities, and the assumption by any such
successor of the covenants of the Company or such obligor herein and in the
Securities, in each case in compliance with the provisions of the Indenture, (x)
to evidence and provide the acceptance of the appointment of a successor trustee
thereunder and (xi) add or modify any other provisions in the Indenture with
respect to matters or questions arising thereunder which the Company and the
Trustee may deem necessary or desirable and which shall not adversely affect the
interests of the Holders of Securities.

12. Defaults and Remedies.

If any Event of Default other than as a result of certain events of bankruptcy,
insolvency or reorganization of the Company or its Subsidiaries occurs and is
continuing, the principal of all the Securities may be declared due and payable
in the manner and with the effect provided in the Indenture. If an Event of
Default occurs as a result of certain events of bankruptcy, insolvency or
reorganization of the Company or its Subsidiaries, the principal of all the
Securities shall become due and payable immediately without any declaration or
other act on the part of the Trustee or any Holder, all as and to the extent
provided in the Indenture.

13. Trustee Dealings with the Company.

Subject to certain limitations imposed by the TIA, the Trustee under the
Indenture, in its individual or any other capacity, may become the owner or
pledgee of Securities and may otherwise deal with and collect obligations owed
to it by the Company or its Affiliates and may otherwise deal with the Company
or its Affiliates with the same rights it would have if it were not Trustee.

14. Calculations in Respect of Securities.

The Company or its agents shall be responsible for making all calculations
called for under the Securities including, but not limited to, determination of
the Market Price and Closing Sale Price of the Applicable Stock, the number of
shares of Applicable Stock and/or the amount of cash issuable or payable upon
conversion and the amounts of interest and Additional Interest, if any, on the
Securities. Any calculations made in good faith and without manifest error shall
be final and binding on Holders of the Securities. The Company or its agents
shall be required to deliver to the Trustee a schedule of its calculations and
the Trustee shall be entitled to conclusively rely upon the accuracy of such
calculations without independent verification.

15. No Recourse Against Others.

No recourse under or upon any obligation, covenant or agreement contained in the
Indenture, or in this

                                      A-9

<PAGE>

Security, or because of any indebtedness evidenced thereby, shall be had against
any incorporator, as such, or against any past, present or future stockholder,
officer or director, as such, of the Company or of any successor, either
directly or through the Company or any successor, under any rule of law, statute
or constitutional provision or by the enforcement of any assessment or by any
legal or equitable proceeding or otherwise, all such liability being expressly
waived and released by the acceptance of the Securities by the Holders and as
part of the consideration for the issue of the Securities.

16. Authentication.

This Security shall not be valid until an authorized signatory of the Trustee
signs, manually or by facsimile, the Trustee's Certificate of Authentication on
the other side of this Security.

17. Abbreviations.

Customary abbreviations may be used in the name of a Holder or an assignee, such
as TEN COM (=tenants in common), TEN ENT (=tenants by the entireties), JT TEN
(=joint tenants with right of survivorship and not as tenants in common), CUST
(=custodian), and U/G/M/A (=Uniform Gift to Minors Act).

18. INDENTURE TO CONTROL; GOVERNING LAW.

IN THE CASE OF ANY CONFLICT BETWEEN THE PROVISIONS OF THIS SECURITY AND THE
INDENTURE, THE PROVISIONS OF THE INDENTURE SHALL CONTROL. THE INDENTURE AND THIS
SECURITY SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE
STATE OF NEW YORK.

The Company shall furnish to any Holder upon written request and without charge
a copy of the Indenture which has in it the text of this Security in larger
type. Requests may be made to:

CONCORD COMMUNICATIONS, INC.

400 Nickerson Road
Marlboro, Massachusetts  01752
Attention:  Chief Financial Officer
Facsimile No.:  (508) 481-9772

with a copy to:
TESTA, HURWITZ & THIBEAULT, LLP
125 High Street
Boston, Massachusetts 02110
Attention:  Kevin M. Barry, Esq.
Facsimile No.: (617) 248-7100

19. Registration Rights.

The Holders of the Securities are entitled to the benefits of a Registration
Rights Agreement, dated as of December 8, 2003, between the Company and Bear,
Stearns & Co. Inc., including the receipt of Additional Interest upon a
registration default (as defined in such agreement).

                                      A-10

<PAGE>

                                 ASSIGNMENT FORM

To assign this Security, fill in the form below:
I or we assign and transfer this Security to

__________________

                   (Insert assignee's soc. sec. or tax ID no.)

____________
____________
__________________

              (Print or type assignee's name, address and zip code)

and irrevocably appoint ____________________________________________ agent to
transfer this Security on the books of the Company. The agent may substitute
another to act for him.

Your Signature(s):

Date:  _______________________ ____________________________________________
                                    (Sign exactly as your name(s) appears on the
                                     other side of this Security)

Signature Guaranteed

_____________________________________
Participant in a Recognized Signature
Guarantee Medallion Program

By:_________
              Authorized Signatory

                                      A-11

<PAGE>

                       OPTION OF HOLDER TO ELECT PURCHASE

If you wish to have this Security purchased by the Company pursuant to Article
IV (Purchase at the Option of Holders on Specific Dates) or Article V (Purchase
at the Option of Holders Upon a Designated Event) of the Indenture, check the
box: Article IV[ ] Article V[ ].

If this Security is to be purchased by the Company pursuant to Article IV of the
Indenture, check the box for the applicable Purchase Date: December 15, 2008 [ ]
December 15, 2013 [ ] December 15, 2018 [ ].

If you wish to have a portion of this Security purchased by the Company pursuant
to Article IV or Article V of the Indenture, as applicable, state the amount (in
Principal Amount): $ ___________.

If certificated, the certificate numbers of the Securities to be delivered for
purchase are: .

Any purchase of Securities pursuant hereto shall be pursuant to the terms and
conditions specified in the Indenture.

                               Your Signature(s):

Date:  _________________ ____________________________________________
                            (Sign exactly as your name(s) appears on the
                             other side of this Security)

Signature Guaranteed

_____________________________________
Participant in a Recognized Signature
Guarantee Medallion Program

By:_________
             Authorized Signatory

                                      A-12

<PAGE>

                                CONVERSION NOTICE

To convert this Security into Common Stock of the Company, check the box[  ].

To convert only part of this Security, state the principal amount to be
converted (which must be $1,000 or an integral multiple of $1,000):____________.

Please check one:

[ ]       I certify that neither I nor any other Person shall become a 10%
         Stockholder upon satisfaction by the Company of the Conversion
         Obligation underlying this Conversion Notice in Common Stock.

[ ]      I do not certify that neither I nor any other Person shall become a 10%
         Stockholder upon satisfaction by the Company of the Conversion
         Obligation underlying this Conversion Notice in Common Stock.

"10% Stockholder" means a Person that owns, directly or indirectly, applying the
provisions of Section 958(a) of the Internal Revenue Code of 1986, as amended
(the "Code"), or by attribution, applying the provisions of Section 958(b) of
the Code, 10% or more of the outstanding shares of Common Stock.

If you want the stock certificate made out in another person's name fill in the
form below:

______________________

               (Insert the other person's soc. sec. or tax ID no.)
____________
____________
____________
          (Print or type the other person's name, address and zip code)

                                    Your Signature(s):

Date:  _______________________  ________________________________________________
                                 (Sign exactly as your name(s) appears on the
                                         other side of this Security)
Signature Guaranteed

_____________________________________
Participant in a Recognized Signature
Guarantee Medallion Program

By:_________
            Authorized Signatory

                              TRANSFER CERTIFICATE(2)
                   RE: 3.0% CONVERTIBLE SENIOR NOTES DUE 2023
       (THE "SECURITIES") OF CONCORD COMMUNICATIONS, INC. (THE "COMPANY")

This certificate relates to $_______ principal amount of Securities owned in
(check applicable box) [ ] book-entry [ ] definitive form by ______________ (the
"Transferor").

The Transferor has requested a Registrar or the Trustee to exchange or register
the transfer of such Securities.

In connection with such request and in respect of each such Security, the
Transferor does hereby certify that the Transferor is familiar with transfer
restrictions relating to the Securities as provided in Section 2.6 and Section
2.12 of the Indenture dated December 8, 2003 between the Company and Wilmington
Trust Company, as Trustee (the "Indenture"), and the transfer of such Security
is being made pursuant to an effective registration statement under the
Securities Act of 1933, as amended (the "Securities Act") (check applicable box)
or the transfer or exchange, as the case may be, of such Security does not
require registration under the Securities Act because (check applicable box):

[ ]      Such Security is being transferred to the Company or a Subsidiary; or

                  [ ]      Such Security is being transferred to a Qualified
                           Institutional Buyer in compliance with Rule 144A
                           under the Securities Act; or

                  [ ]      Such Security is being transferred pursuant to and in
                           compliance with an exemption from the registration
                           requirements under the Securities Act in accordance
                           with Rule 144 (or any successor thereto) ("Rule 144")
                           under the Securities Act; or

                  [ ]      Such Security is being transferred to an
                           institutional investor that is an "accredited
                           investor" (as defined in Rule 501(a)(1), (2), (3) or
                           (7) under the Securities Act)

----------
(2) This certificate should only be included if this Security is a Transfer
Restricted Security.

                                      A-13

<PAGE>

                           that has transferred a letter making certain
                           representations, warranties and agreements relating
                           to restrictions on transfer and an opinion of counsel
                           to EquiServe, LLP as transfer agent (or any successor
                           transfer agent, as applicable) that such transfer is
                           in compliance with the Securities Act.

                  [ ]      Such Security is being transferred pursuant to an
                           effective registration statement under the Securities
                           Act; or

                  [ ]      Such Security is being acquired for the Transferor's
                           own account, without transfer.

The Transferor acknowledges and agrees that, if the transferee shall hold any
such Securities in the form of beneficial interests in a Global Security which
is a "restricted security" within the meaning of Rule 144 under the Securities
Act, then such transfer can only be made pursuant to Rule 144A under the
Securities Act and such transferee must be a "qualified institutional buyer" (as
defined in Rule 144A).

Date: ____________
                           Signature(s) of Transferor

(If the registered owner is a corporation, partnership or fiduciary, the title
of the person signing on behalf of such registered owner must be stated.)
Signature Guaranteed

_____________________________________
Participant in a Recognized Signature
Guarantee Medallion Program

By: __________________________
         Authorized Signatory

                                      A-14

<PAGE>

                                    EXHIBIT B
                     [FORM OF CERTIFICATE TO BE DELIVERED BY
                     TRANSFEREE IN CONNECTION WITH TRANSFERS
                     TO INSTITUTIONAL ACCREDITED INVESTORS]

                                                                          [DATE]

Wilmington Trust Company, as Trustee
1100 North Market Street, Rodney Square North
Wilmington, DE  19890-1615
Attention:  Corporate Capital Markets
EquiServe, LLP,
as Transfer Agent
Re:      Concord Communications, Inc.

Ladies and Gentlemen:

In connection with the undersigned's proposed purchase of $____________
aggregate principal amount of 3.0% Convertible Senior Notes due 2023 (the
"Notes") of Concord Communications, Inc. (the "Company") or _____________ shares
of Common Stock of the Company issued upon conversion of the Notes, par value
$.01 per share (the "Common Stock," and together with the Notes, the
"Securities"), the undersigned confirms, represents and warrants that:

         (1)      The undersigned is an institutional "accredited investor"
         within the meaning of Rule 501(a)(1), (2), (3) or (7) under the
         Securities Act of 1933, as amended (the "Securities Act") (an
         "Institutional Accredited Investor").

         (2)      (A) Any purchase of the Securities by the undersigned shall be
         for the undersigned's own account or for the account of one or more
         other Institutional Accredited Investors or as fiduciary for the
         account of one or more trusts, each of which is an "accredited
         investor" within the meaning of Rule 501(a)(7) under the Securities Act
         and for each of which the undersigned exercises sole investment
         discretion or (B) the undersigned is a "bank", within the meaning of
         Section 3(a)(2) of the Securities Act, or a "savings and loan
         association" or other institution described in Section 3(a)(5)(A) of
         the Securities Act that is acquiring the Securities as fiduciary for
         the account of one or more institutions for which the undersigned
         exercises sold investment discretion.

         (3)      The undersigned has such knowledge and experience in financial
         and business matters that the undersigned is capable of evaluating the
         merits and risks of its investment in the Securities, and the
         undersigned and any accounts for which it is acting is each able to
         bear the economic risk of its or their investment.

         (4)      The undersigned has been given an opportunity to ask questions
         and receive answers concerning the terms and conditions of the
         Securities and to obtain any additional information which the Company
         possesses or can acquire without reasonable effort or expense that is
         necessary to verify the accuracy of the information furnished.

         (5)      The undersigned is not acquiring the Securities with a view to
         distribution thereof or with any present intention of offering or
         selling any Securities, except as permitted below; provided that the
         disposition of the undersigned's property and the property of any
         accounts for which the undersigned is acting as fiduciary shall remain
         at all times within the undersigned's control.

         (6)      The undersigned understands that the Securities have not been
         registered under the Securities Act or any applicable state securities
         laws.

         (7)      The undersigned agrees, on its own behalf and on behalf of
         each account for which the undersigned acquires any Securities, that if
         in the future the undersigned decides to resell or otherwise transfer
         such Securities within two years after the original issuance of the
         Notes, such Securities may be resold or otherwise transferred only:

                           (A)      to the Company or any subsidiary thereof;

                                      B-1

<PAGE>

                           (B)      with respect to Notes only, to a person
                  which is a "qualified institutional buyer" (as defined in Rule
                  144A under the Securities Act) in compliance with Rule 144A
                  under the Securities Act;

                           (C)      pursuant to the exemption from registration
                  provided by Rule 144 under the Securities Act (if available);

                           (D)      pursuant to an exemption from registration
                  under the Securities Act to an Institutional Accredited
                  Investor that prior to such transfer, furnishes to you (and
                  the Trustee or the Transfer Agent, as the case may be) a
                  signed letter substantially in the form of this letter, a
                  transfer certificate substantially in the form provided in the
                  Indenture and an opinion of counsel; or

                           (E)      pursuant to a registration statement which
                  has been declared effective under the Securities Act and
                  continues to be effective at the time of such transfer.

         The undersigned further agrees to provide to any person purchasing any
         of the Securities from us a notice advising such purchaser that resales
         of the Securities are restricted as stated herein.

         (8)      The undersigned understands that, on any proposed resale of
         any Securities, the undersigned shall be required to furnish to the
         Trustee or the Transfer Agent, as the case may be, and the Company such
         certifications, legal opinions and other information as you and the
         Company may reasonably require to confirm that the proposed sale
         complies with the foregoing restrictions. The undersigned further
         understands that the Securities purchased by the undersigned shall be
         certificated securities and shall bear a legend to the foregoing
         effect.

Each of the Company, the Trustee or the Transfer Agent, as the case may be, and
the initial purchasers of the Securities are entitled to rely upon this letter
and are irrevocably authorized to produce this letter or a copy hereof to any
interested party in any administrative or legal proceedings or official inquiry
with respect to the matters covered hereby.

                                Very truly yours,

                           By:_
                              Name:
                              Title:
                              Address:

                                      B-2

<PAGE>

                                    EXHIBIT C

                         [FORM OF RESTRICTIVE LEGEND FOR
                      COMMON STOCK ISSUED UPON CONVERSION]

THE SECURITY EVIDENCED BY THIS CERTIFICATE HAS NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT OF 1933"), OR ANY STATE
SECURITIES LAWS, AND MAY NOT BE OFFERED OR SOLD EXCEPT AS SET FORTH IN THE
FOLLOWING SENTENCE. BY ACQUISITION HEREOF, THE HOLDER:

         (1)      REPRESENTS THAT (A) IT IS A "QUALIFIED INSTITUTIONAL BUYER" AS
         DEFINED IN RULE 144A UNDER THE SECURITIES ACT OF 1933 OR (B) IT IS AN
         INSTITUTIONAL INVESTOR THAT IS AN "ACCREDITED INVESTOR" AS DEFINED IN
         RULE 501(a)(1), (2), (3), OR (7) UNDER THE SECURITIES ACT (AN
         "INSTITUTIONAL ACCREDITED INVESTOR");

         (2)      AGREES THAT IT SHALL NOT, WITHIN TWO YEARS AFTER THE ORIGINAL
         ISSUANCE OF THE SECURITY UPON THE CONVERSION OF WHICH THE SHARES OF
         COMMON STOCK EVIDENCED HEREBY WERE ISSUED, RESELL OR OTHERWISE TRANSFER
         THE SECURITY EVIDENCED HEREBY EXCEPT (A) TO THE COMPANY OR ANY
         SUBSIDIARY THEREOF, (B) PURSUANT TO THE EXEMPTION FROM REGISTRATION
         PROVIDED BY RULE 144 UNDER THE SECURITIES ACT OF 1933 (IF AVAILABLE),
         (C) PURSUANT TO AN EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE
         SECURITIES ACT OF 1933 (IF AVAILABLE) TO AN INSTITUTIONAL ACCREDITED
         INVESTOR THAT PRIOR TO SUCH TRANSFER, FURNISHES TO EQUISERVE, LLP, AS
         TRANSFER AGENT (OR ANY SUCCESSOR TRANSFER AGENT, AS APPLICABLE),
         CERTIFICATIONS AND OPINION OF COUNSEL REQUIRED BY THE COMPANY OR
         TRANSFER AGENT OR (D) PURSUANT TO A REGISTRATION STATEMENT THAT HAS
         BEEN DECLARED EFFECTIVE UNDER THE SECURITIES ACT OF 1933 AND THAT
         CONTINUES TO BE EFFECTIVE AT THE TIME OF SUCH TRANSFER; AND

         (3)      AGREES THAT IT SHALL DELIVER TO EACH PERSON TO WHOM THE
         SECURITY EVIDENCED HEREBY IS TRANSFERRED (OTHER THAN A TRANSFER
         PURSUANT TO CLAUSE 2(B) OR 2(D) ABOVE), A NOTICE SUBSTANTIALLY TO THE
         EFFECT OF THIS LEGEND.]

                                      C-1