<PAGE>

                                                                     EXHIBIT 4.1

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                         LEVEL 3 COMMUNICATIONS, INC.


                                      AND


                             THE BANK OF NEW YORK
                                  as Trustee


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


                         SECOND SUPPLEMENTAL INDENTURE

                         DATED AS OF FEBRUARY 29, 2000


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



            Supplement to Indenture dated as of September 20, 1999
                        (Subordinated Debt Securities)



                  6% Convertible Subordinated Notes due 2010


================================================================================
<PAGE>

                                                                               1
                         SECOND SUPPLEMENTAL INDENTURE


          SECOND SUPPLEMENTAL INDENTURE, dated as of February 29, 2000 by and
between LEVEL 3 COMMUNICATIONS, INC., a Delaware corporation (hereinafter called
the "Company"), and THE BANK OF NEW YORK as successor to IBJ WHITEHALL BANK &
TRUST COMPANY, a corporation duly organized and existing under the laws of the
State of New York (hereinafter called the "Trustee"), having a Corporate Trust
Office at 101 Barclay Street, Floor 21 West New York, New York 10286, as Trustee
under the Indenture (as hereinafter defined).


                                    RECITALS

          WHEREAS, the Company and the Trustee have as of September 20, 1999
entered into an Indenture (hereinafter called the "Indenture"), providing for
the issuance by the Company from time to time of its subordinated debt
securities;

          WHEREAS, no Securities have been issued under the Indenture and there
do not currently exist any Holders;

          WHEREAS, Section 901 of the Indenture provides, among other things,
that the Company, when authorized by or pursuant to a Board Resolution, and the
Trustee may without the consent of any Holders of Securities enter into one or
more indentures supplemental to the Indenture to establish the form or terms of
Securities of any series, including the provisions and procedures providing for
the adjustment of conversion rights with respect to Securities convertible into
Common Stock or to change or eliminate any of the provisions of the Indenture,
provided that any such change or elimination shall become effective only when
--------
there is no Security Outstanding of any series created prior to the execution of
such supplemental indenture which is entitled to the benefit of such provision;

          WHEREAS, the Company desires to issue one series of convertible
subordinated debt securities under the Indenture, and has duly authorized the
creation and issuance of such debt securities and the execution and delivery of
this Second Supplemental Indenture to modify the Indenture and provide certain
additional provisions as hereinafter described;

          WHEREAS, the Company and the Trustee deem it advisable to enter into
this Second Supplemental Indenture for the purposes of establishing the terms of
such convertible subordinated debt securities and providing for the rights,
obligations and duties of the Trustee with respect to such debt securities;


          WHEREAS, concurrent with the execution hereof, the Company has
delivered an Officers' Certificate and has caused its counsel to deliver to the
Trustee an Opinion of Counsel or a reliance letter upon an opinion of counsel;
and

          WHEREAS, all conditions and requirements of the Indenture necessary to
make this Second Supplemental Indenture a valid, binding and legal instrument in
accordance with its terms have been performed and fulfilled by the parties
hereto and the
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                                                                               2

execution and delivery thereof have been in all respects duly authorized by the
parties hereto.


          NOW, THEREFORE, THIS SECOND SUPPLEMENTAL INDENTURE WITNESSETH:

          For and in consideration of the mutual premises and agreements herein
contained, the Company and the Trustee covenant and agree, for the equal and
proportionate benefit of all Holders of the Securities, as follows:


                                  ARTICLE ONE

                          CREATION OF THE SECURITIES

          SECTION 1.1.  DESIGNATION OF SERIES.  Pursuant to the terms hereof and
                       -----------------------
Sections 201 and 301 of the Indenture, the Company hereby creates a series of
its convertible subordinated debt securities designated as the "6% Convertible
Subordinated Notes due 2010" (the "Notes"), which Notes shall be deemed
"Securities" for all purposes under the Indenture.

          SECTION 1.2.  FORM OF SECURITIES.  (a)  The Securities will be issued
                        -------------------
in permanent global form without coupons and the definitive form of the
Securities shall be substantially in the form set forth in Exhibit A attached
hereto, which is incorporated herein and made part hereof. The Securities shall
bear interest, be payable and have such other terms as are stated in the form of
definitive Security or in the Indenture, as supplemented by this Second
Supplemental Indenture. The Stated Maturity of the Securities shall be March 15,
2010.

          (b)  The fifth paragraph of Section 305 of the Indenture is hereby
amended with respect to the Securities by replacing clause (y) in the fourth
sentence thereof with the following:

          "(y)  an Event of Default or an event which after notice or lapse of
     time or both would be an Event of Default has occurred and is continuing
     and the beneficial owners representing a majority in principal amount of
     the Securities represented by such global Securities advise DTC to cease
     acting as depositary for such global Securities or".

          SECTION 1.3.  LIMIT ON AMOUNT OF SERIES.  The Securities shall not
                        --------------------------
exceed $862,500,000 in aggregate principal amount, and may, upon the execution
and delivery of this Second Supplemental Indenture or from time to time
thereafter, be executed by the Company and delivered to the Trustee for
authentication, and the Trustee shall thereupon authenticate and deliver said
Securities to or upon the written order of the Company, signed by its Chairman
of the Board, President or one of its Vice Presidents and by its Treasurer, one
of its Assistant Treasurers, its Secretary or one of its Assistant Secretaries,
without further action by the Company.
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                                                                               3

          SECTION 1.4.  CERTIFICATE OF AUTHENTICATION.  The Trustee's
                        ------------------------------
certificate of authentication to be borne on the Securities shall be
substantially as provided in the Form of Security attached hereto as Exhibit A.

          SECTION 1.5.  NO SINKING FUND.  No sinking fund will be provided with
                        ----------------
respect to the Securities.

          SECTION 1.6.  NO ADDITIONAL AMOUNTS.  No Additional Amounts will be
                        ----------------------
payable with respect to the Securities.

          SECTION 1.7.  DEFINITIONS.
                        ------------

          (a)  Capitalized terms used herein and not otherwise defined shall
have the respective meanings assigned thereto in the Indenture.

          (b)  Solely for purposes of this Second Supplemental Indenture and the
Securities, the following definitions are hereby amended in their entirety to
read as follows:

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

          "Senior Indebtedness" means the principal of, and premium, if any, and
           -------------------
     interest, including all interest accruing subsequent to the commencement of
     any bankruptcy or similar proceeding, whether or not a claim for post-
     petition interest is allowable as a claim in any such proceeding, on, and
     all fees and other amounts payable in connection with, the following,
     whether absolute or contingent, secured or unsecured, due or to become due,
     outstanding on the date of the Indenture or thereafter created, incurred or
     assumed:

               (1) indebtedness of the Company evidenced by a credit or loan
          agreement, note, bond, debenture or other written obligation,

               (2) all obligations of the Company for money borrowed,

               (3) all obligations of the Company evidenced by a note or similar
          instrument given in connection with the acquisition of any businesses,
          properties or assets of any kind,

               (4) obligations of the Company (A) as lessee under leases
          required to be capitalized on the balance sheet of the lessee under
          generally accepted accounting principles and (B) as lessee under other
          leases for facilities, capital equipment or related assets, whether or
          not capitalized, entered into or leased for financing purposes,

               (5) all obligations of the Company under interest rate and
          currency swaps, caps, floors, collars, hedge agreements, forward
          contracts or similar agreements or arrangements,
<PAGE>

                                                                               4

               (6) all obligations of the Company with respect to letters of
          credit, bankers' acceptances and similar facilities, including
          reimbursement obligations with respect to the foregoing,

               (7) all obligations of the Company issued or assumed as the
          deferred purchase price of property or services, but excluding trade
          accounts payable and accrued liabilities arising in the ordinary
          course of business,

               (8) all obligations of the type referred to in clauses (1)
          through (7) of another Person and all dividends of another person, the
          payment of which, in either case, the Company has assumed or
          guaranteed, or for which the Company is responsible or liable,
          directly or indirectly, jointly or severally, as obligor, guarantor or
          otherwise, or which is secured by a lien on the property of the
          Company, and

               (9) renewals, extensions, modifications, replacements,
          restatements and refundings of, or any indebtedness or obligation
          issued in exchange for, any such indebtedness or obligation described
          in clauses (1) through (8) hereof;

     provided, however, that Senior Indebtedness shall not include the
     Securities or any such indebtedness or obligation if the terms of such
     indebtedness or obligation, or the terms of the instrument under which, or
     pursuant to which it is issued expressly provide that such indebtedness or
     obligation is not superior in right of payment to the Securities.

          "Subsidiary" of any Person means (i) a corporation more than 50% of
           ----------
     the combined voting power of the outstanding Voting Stock of which is
     owned, directly or indirectly, by such Person or by one or more other
     Subsidiaries of such Person or by such Person and one or more Subsidiaries
     thereof or (ii) any other Person (other than a corporation) in which such
     Person, or one or more other Subsidiaries of such Person or such Person and
     one or more other Subsidiaries thereof, directly or indirectly, has at
     least a majority ownership and power to direct the policies, management and
     affairs thereof.

          (c)  Solely for purposes of this Second Supplemental Indenture and the
Securities, the following terms shall have the indicated meanings:

          "Capital Stock" of any Person means any and all shares, interest,
           -------------
     participations or other equivalents (however designated) of corporate stock
     or equity participations, including partnership interests, whether general
     or limited, of such Person and any rights (other than debt securities
     convertible or exchangeable into any equity interest), warrants or options
     to acquire an equity interest in such person.

          "Change of Control" at such time after the original issuance of the
           -----------------
     Securities means the occurrence of the following events:

               (1) if any "person" or group " (as such terms are used in
          Sections 13(d) and 14(d) of the Exchange Act or any successor
     provisions
<PAGE>

                                                                               5

     to either of the foregoing), including any group acting for the purpose of
     acquiring, holding, voting or disposing of securities within the meaning of
     Rule 13d-5(b)(1) under the Exchange Act, other than any one or more of the
     Permitted Holders, becomes the "beneficial owner" (as defined in Rule 13d-3
     under the Exchange Act, except that a person will be deemed to have
     "beneficial ownership" of all shares that any such person has the right to
     acquire, whether such right is exercisable immediately or only after the
     passage of time), directly or indirectly, of 35% or more of the total
     voting power of the Voting Stock of the Company; provided, however, that
     the Permitted Holders are the "beneficial owners" (as defined in Rule 13d-3
     under the Exchange Act, except that a person will be deemed to have
     "beneficial ownership" of all shares that any such person has the right to
     acquire, whether such right is exercisable immediately or only after the
     passage of time), directly or indirectly, in the aggregate of a lesser
     percentage of the total voting power of the Voting Stock of the Company
     than such other person or group (for purposes of this clause (1), such
     person or group shall be deemed to beneficially own any voting stock of a
     corporation (the "specified corporation") held by any other corporation
     (the "parent corporation") so long as such person or group beneficially
     owns, directly or indirectly, in the aggregate a majority of the total
     voting power of the Voting Stock of such parent corporation); or

               (2) the sale, transfer, assignment, lease, conveyance or other
     disposition, directly or indirectly, of all or substantially all the assets
     of the Company and its subsidiaries, considered as a whole (other than a
     disposition of such assets as an entirety or virtually as an entirety to a
     wholly owned subsidiary or one or more Permitted Holders) shall have
     occurred; or

               (3) during any period of two consecutive years, individuals who
     at the beginning of such period constituted the Board of Directors of the
     Company (together with any new directors whose election or appointment by
     such Board or whose nomination for election by the stockholders of the
     Company was approved by a vote of a majority of the directors then still in
     office who were either directors at the beginning of such period or whose
     election or nomination for election was previously so approved) cease for
     any reason to constitute a majority of the Board of Directors of the
     Company then in office; or

               (4) the stockholders of the Company shall have approved any plan
     of liquidation or dissolution of the Company;

provided, however, that a Change of Control shall not be deemed to have occurred
--------  -------
if the Current Market Price of the Common Stock of the Company for any five
Trading Days within the period of 10 consecutive Trading Days beginning
immediately after the later of the Change of Control or the public announcement
of the Change of Control shall equal or exceed 105% of the Conversion Price in
effect on each such Trading Day; provided further that if the Change of Control
                                 -------- -------
results in the reclassification, conversion, exchange of outstanding shares of
<PAGE>

                                                                               6

     Common Stock of the Company, such 10 consecutive Trading Day period shall
     be measured as ending immediately before the Change of Control.

          "Conversion Price" shall equal $1,000 divided by the Conversion Rate
           ----------------
     (rounded to the nearest cent, with one-half cent being rounded upward).

          "Current Market Price" of Common Stock of the Company for any day
           --------------------
     means the last reported per share sale price, regular way on such day, or,
     if no sale takes place on such day, the average of the reported closing per
     share bid and asked prices on such day, regular way, in either case as
     reported on the Nasdaq National Market or, if such Common Stock is not
     quoted or admitted to trading on such quotation system, on the principal
     national securities exchange or quotation system on which such Common Stock
     may be listed or admitted to trading or quoted, or, if not listed or
     admitted to trading or quoted on any national securities exchange or
     quotation system, the average of the closing per share bid and asked prices
     of such Common Stock on the over-the-counter market on the day in question
     as reported by the National Quotation Bureau Incorporated, or similar
     generally accepted reporting service, or, if not so available in such
     manner, as furnished by any Nasdaq member firm selected from time to time
     by the Board of Directors of the Company for that purpose, or, if not so
     available in such manner, as otherwise determined in good faith by the
     Board of Directors of the Company.

          "Dollar Denominated Senior Notes Indenture" means the Indenture dated
           -----------------------------------------
     as of February 29, 2000, as amended, supplemented or modified from time to
     time, between the Company and The Bank of New York, as trustee, relating to
     the Company's 11% Senior Notes due 2008, 11-1/4% Senior Notes due 2010 and
     12-7/8% Senior Discount Notes due 2010.

          "Euro Denominated Senior Notes Indenture" means the Indenture dated as
           ---------------------------------------
     of February 29, 2000, as amended, supplemented or modified from time to
     time, between the Company and The Bank of New York, as trustee, relating to
     the Company's 10-3/4% Senior Notes due 2008 and 11-1/4% Senior Notes due
     2010.

          "Exchange Act" means the Securities Exchange Act of 1934.
           ------------

          "Expiration Date" has the meaning specified in "Offer to Purchase"
           ---------------
     below.

          "Federal Bankruptcy Code" means the Bankruptcy Act of Title 11 of the
           -----------------------
     United States Code, as amended from time to time.

          "First Supplemental Indenture" means the Supplemental Indenture dated
           ----------------------------
     as of September 20, 1999, together with the related Indenture dated as of
     September 20, 1999, as amended, supplemented or modified from time to time,
     between the Company and The Bank of New York as successor to IBJ Whitehall
     Bank & Trust Company, as trustee, relating to the Company's 6% Convertible
     Subordinated Notes due 2009.

          "Indebtedness" means, with respect to a Person:
           ------------

               (1) indebtedness of such Person evidenced by a credit or loan
          agreement, note, bond, debenture or other written obligation,
<PAGE>

                                                                               7

               (2)  all obligations of such Person for money borrowed,

               (3)  all obligations of such Person evidenced by a Security or
          similar instrument given in connection with the acquisition of any
          businesses, properties or assets of any kind,

               (4)  obligations of such Person (A) as lessee under leases
          required to be capitalized on the balance sheet of the lessee under
          generally accepted accounting principles and (B) as lessee under other
          leases for facilities, capital equipment or related assets, whether or
          not capitalized, entered into or leased for financing purposes,

               (5)  all obligations of such Person under interest rate and
          currency swaps, caps, floors, collars, hedge agreements, forward
          contracts or similar agreements or arrangements,

               (6)  all obligations of such Person with respect to letters of
          credit, bankers' acceptances and similar facilities, including
          reimbursement obligations with respect to the foregoing,

               (7)  all obligations of such Person issued or assumed as the
          deferred purchase price of property or services, but excluding trade
          accounts payable and accrued liabilities arising in the ordinary
          course of business,

               (8)  all obligations of the type referred to in clauses (1)
          through (7) of another Person and all dividends of another person, the
          payment of which, in either case, such Person has assumed or
          guaranteed, or for which such Person is responsible or liable,
          directly or indirectly, jointly or severally, as obligor, guarantor or
          otherwise, or which is secured by a lien on the property of such
          Person, and

               (9)  renewals, extensions, modifications, replacements,
          restatements and refundings of, or any indebtedness or obligation
          issued in exchange for, any such indebtedness or obligation described
          in clauses (1) through (8) hereof.

          "9-1/8% Senior Notes Indenture" means the Indenture dated as of April
           -----------------------------
     28, 1998, as amended, supplemented or modified from time to time, between
     the Company and The Bank of New York (as successor to IBJ Schroder Bank &
     Trust Company), as trustee, relating to the Company's 9-1/8% Senior Notes
     Due 2008.

          "Offer" has the meaning specified in "Offer to Purchase" below.
           -----

          "Offer to Purchase" means a written offer (the "Offer") sent by the
           -----------------
     Company by first-class mail, postage prepaid, to each Holder of Securities
     at its address appearing in the Security Register on the date of the Offer
     offering to purchase up to the principal amount of Securities specified in
     such Offer at the purchase price specified in such Offer (as determined
     pursuant to this Indenture). Unless otherwise required by applicable law,
     the Offer shall specify an expiration date (the "Expiration Date") of the
     Offer to Purchase which shall be, subject to any contrary requirements of
     applicable law, not less than 30 days or more than
<PAGE>

                                                                               8

     60 days after the date of such Offer and a settlement date (the "Purchase
     Date") for purchase of Securities within five Business Days after the
     Expiration Date. The Company shall notify the Trustee at least 15 Business
     Days (or such shorter period as is acceptable to the Trustee) prior to the
     mailing of the Offer of the Company's obligation to make an Offer to
     Purchase, and the Offer shall be mailed by the Company or, at the Company's
     request, by the Trustee in the name and at the expense of the Company. The
     Offer shall contain information concerning the business of the Company and
     its Subsidiaries which the Company in good faith believes will enable such
     Holders to make an informed decision with respect to the Offer to Purchase
     (which at a minimum will include (i) the most recent annual and quarterly
     financial statements and "Management's Discussion and Analysis of Financial
     Condition and Results of Operations" contained in the documents required to
     be filed under the Exchange Act (which requirements may be satisfied by
     delivery of such documents together with the Offer), (ii) a description of
     material developments in the Company's business subsequent to the date of
     the latest of such financial statements referred to in clause (i)
     (including a description of the events requiring the Company to make the
     Offer to Purchase), (iii) if applicable, appropriate pro forma financial
     information concerning the Offer to Purchase and the events requiring the
     Company to make the Offer to Purchase and (iv) any other information
     required by applicable law to be included therein). The Offer shall contain
     all instructions and materials necessary to enable such Holders to tender
     Securities pursuant to the Offer to Purchase. The Offer shall also state:

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

               (2) the Expiration Date and the Purchase Date;

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

               (4) the purchase price to be paid by the Company for $1,000
     aggregate principal amount of Securities accepted for payment (as specified
     pursuant to the Indenture) (the "Purchase Price") and whether the Purchase
     Price shall be paid by the Company in cash or by delivery of shares of
     Common Stock of the Company;

               (5) that the Holder may tender all or any portion of the
     Securities registered in the name of such Holder and that any portion of a
     Security tendered must be tendered in a principal amount equal to $5,000 or
     any integral multiple of $1,000 in excess thereof;

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

               (7) that any Securities not tendered or tendered but not
     purchased by the Company will continue to accrue interest;

               (8) that on the Purchase Date the Purchase Price will become due
     and payable upon each Security being accepted for payment pursuant to
<PAGE>

                                                                               9

     the Offer to Purchase and that interest thereon, if any, shall cease to
     accrue on and after the Purchase Date;

               (9) that each Holder electing to tender a Security pursuant to
     the Offer to Purchase will be required to surrender such Security at the
     place or places specified in the Offer prior to the close of business on
     the Expiration Date (such Security being, if the Company or the Trustee so
     requires, duly endorsed by, or accompanied by a written instrument of
     transfer in form satisfactory to the Company and the Trustee duly executed
     by, the Holder thereof or his or her attorney duly authorized in writing);

               (10) in the event that the Purchase Price shall be paid in shares
     of Common Stock of the Company, that each Holder electing to tender a
     Security pursuant to the Offer to Purchase will be required to provide
     written notification of the name or names (with addresses) in which the
     certificate or certificates for shares of such Common Stock shall be
     issued;

               (11) that Holders will be entitled to withdraw all or any portion
     of Securities tendered if the Company (or the Paying Agent) receives, not
     later than the close of business on the Expiration Date, a facsimile
     transmission or letter setting forth the name of the Holder, the principal
     amount of the Security the Holder tendered, the certificate number of the
     Security the Holder tendered and a statement that such Holder is
     withdrawing all or a portion of his tender;

               (12) that if Securities in an aggregate principal amount less
     than or equal to the Purchase Amount are duly tendered and not withdrawn
     pursuant to the Offer to Purchase, the Company shall purchase all such
     Securities;

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

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

          Any Offer to Purchase shall be governed by and effected in accordance
     with the Offer for such Offer to Purchase.

          "Permitted Holders" means the members of the Company's Board of
           -----------------
     Directors on April 28, 1998 and their respective estates, spouses,
     ancestors, and lineal descendants, the legal representatives of any of the
     foregoing and the trustees of any bona fide trusts of which the foregoing
     are the sole beneficiaries or the grantors, or any person of which the
     foregoing "beneficially owns" (as defined
<PAGE>

                                                                              10

     in Rule 13d-3 under the Exchange Act) at least 66 2/3% of the total voting
     power of the Voting Stock of such person.

          "Property" means, with respect to any Person, any interest of such
           --------
     Person in any kind of property or asset, whether real, personal or mixed,
     or tangible or intangible, including Capital Stock in, and other securities
     of, any other Person.

          "Purchase Amount" has the meaning specified in "Offer to Purchase"
           ---------------
     above.

          "Purchase Date" has the meaning specified in "Offer to Purchase"
           -------------
     above.

          "Purchase Price" has the meaning specified in "Offer to Purchase"
           --------------
     above.

          "Restricted Subsidiary" means any Restricted Subsidiary under each of
           ---------------------
     the 9-1/8% Senior Notes Indenture and the 10-1/2% Senior Discount Notes
     Indenture.

          "Securities Act" means the Securities Act of 1933, as amended.
           --------------

          "Significant Subsidiary" means any Subsidiary that would be a
           ----------------------
     "Significant Subsidiary" of the Company within the meaning of Rule 1-02
     under Regulation S-X promulgated by the Commission.

          "10-1/2% Senior Discount Notes Indenture" means the Indenture dated as
           ---------------------------------------
     of December 2, 1998, as amended, supplemented or modified from time to
     time, between the Company and IBJ Schroder Bank & Trust Company, as
     trustee, relating to the Company's 10-1/2% Senior Discount Notes Due 2008.

          "Trading Day" with respect to the Common Stock of the Company means
           -----------
     (x) if such Common Stock is listed or admitted for trading on the New York
     Stock Exchange or another national securities exchange, a day on which the
     New York Stock Exchange or such other national securities exchange is open
     for business or (y) if such Common Stock is quoted on the National Market
     System of the Nasdaq, a day on which trades may be made on such National
     Market System or (z) otherwise, any day other than a Saturday or Sunday or
     a day on which banking institutions in the State of New York are authorized
     or obligated by law or executive order to close.

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

                                                                              11

                                  ARTICLE TWO

                            CONVERSION OF SECURITIES

          SECTION 2.1.  APPLICABILITY OF CONVERSION PROVISIONS. Pursuant to
                        ---------------------------------------
Section 301(24) of the Indenture, the Securities will be convertible in
accordance with the provisions of, and pursuant to, Article Sixteen of the
Indenture, as amended hereby, and the definitive form of the Securities.

          SECTION 2.2.  CONVERSION RATE.  The rate at which shares of Common
                        ----------------
Stock of the Company shall be delivered upon conversion (the "Conversion Rate")
shall be initially 7.416 shares of Common Stock of the Company for each $1,000
principal amount of Securities. The Conversion Rate shall be adjusted in certain
instances as provided in Section 1605 of the Indenture, as amended hereby.

          SECTION 2.3.  AMENDMENTS TO ARTICLE SIXTEEN.
                        ------------------------------

          (a)  Section 1605 is amended in its entirety with respect to the
Securities to read as follows:

          SECTION 1605.  Adjustment Of Conversion Rate.

          (1)  In case at any time after the date of the issuance of the
Securities, the Company shall pay or make a dividend or other distribution on
any class of Capital Stock of the Company payable in shares of Common Stock of
the Company, the Conversion Rate in effect at the opening of business on the day
following the date fixed for the determination of stockholders entitled to
receive such dividend or other distribution shall be increased by dividing such
Conversion Rate by a fraction of which the numerator shall be the number of
shares of Common Stock of the Company outstanding at the close of business on
the date fixed for such determination and the denominator shall be the sum of
such number of shares and the total number of shares constituting such dividend
or other distribution, such increase to become effective immediately after the
opening of business on the day following the date fixed for such determination.
For the purposes of this paragraph (1), the number of shares of Common Stock of
the Company at any time outstanding shall not include shares held in the
treasury of the Company but shall include shares issuable in respect of scrip
certificates issued in lieu of fractions of shares of Common Stock of the
Company. The Company will not pay any dividend or make any distribution on
shares of Common Stock of the Company held in the treasury of the Company.

          (2)  In case at any time after the date of the issuance of the
Securities, the Company shall issue rights, options or warrants to all holders
of its Common Stock (other than any rights, options or warrants that by their
terms will also be issued to any Holder upon conversion of a Security into
Common Stock of the Company without any action required by the Company or any
other person) entitling them to subscribe for or purchase shares of Common Stock
of the Company (or securities convertible into Common Stock of the Company) at a
price per share (or having a conversion price per share) less than the Average
Current Market Price per share (determined as provided in paragraph (8) of this
Section) on the date fixed for the determination of stockholders entitled to
receive such rights, options or warrants (other than pursuant to a dividend
reinvestment plan), the Conversion Rate in effect at the opening of business on
the day following the date fixed
<PAGE>

                                                                              12

for such determination shall be increased by dividing such Conversion Rate by a
fraction of which the numerator shall be the number of shares of Common Stock of
the Company outstanding at the close of business on the date fixed for such
determination plus the number of shares of Common Stock of the Company which the
aggregate of the offering price of the total number of shares of Common Stock of
the Company so offered (or the aggregate conversion price of the convertible
securities so offered) for subscription or purchase would purchase at such
Average Current Market Price and the denominator shall be the number of shares
of Common Stock of the Company outstanding at the close of business on the date
fixed for such determination plus the number of shares of Common Stock of the
Company so offered for subscription or purchase (or into which the convertible
securities so offered are convertible), such increase to become effective
immediately after the opening of business on the day following the date fixed
for such determination. For the purposes of this paragraph (2), the number of
shares of Common Stock of the Company at any time outstanding shall not include
shares held in the treasury of the Company but shall include shares issuable in
respect of scrip certificates issued in lieu of fractions of shares of Common
Stock of the Company. The Company will not issue any rights, options or warrants
in respect of shares of Common Stock of the Company held in the treasury of the
Company.

          (3)  In case at any time after the date of the issuance of the
Securities, outstanding shares of Common Stock of the Company shall be
subdivided into a greater number of shares of Common Stock of the Company, the
Conversion Rate in effect at the opening of business on the day following the
day upon which such subdivision becomes effective shall be proportionately
increased, and, conversely, in case outstanding shares of Common Stock of the
Company shall be combined into a smaller number of shares of Common Stock of the
Company, the Conversion Rate in effect at the opening of business on the day
following the day upon which such combination becomes effective shall be
proportionately reduced, such reduction or increase, as the case may be, to
become effective immediately after the opening of business on the day following
the day upon which such subdivision or combination becomes effective.

          (4)  In case at any time after the date of the issuance of the
Securities, the Company shall, by dividend or otherwise, distribute to all
holders of its Common Stock, shares of any class of its Capital Stock, evidences
of its indebtedness or other assets (including securities, but excluding any
rights, options or warrants referred to in paragraph (2) of this Section, any
dividend or distribution paid exclusively in cash and any dividend or
distribution referred to in paragraph (1) of this Section), the Conversion Rate
shall be adjusted so that the same shall equal the price determined by dividing
the Conversion Rate in effect immediately prior to the close of business on the
date fixed for the determination of stockholders entitled to receive such
distribution by a fraction of which the numerator shall be the Average Current
Market Price per share (determined as provided in paragraph (8) of this Section)
on the date fixed for such determination less the then fair market value (as
determined by the Board of Directors, whose determination shall be conclusive
and described in a Board Resolution filed with the Trustee) of the portion of
the assets, shares of capital stock or evidences of indebtedness so distributed
applicable to one share of Common Stock of the Company and the denominator shall
be such Average Current Market Price per share, such adjustment to become
effective immediately prior to the opening of business on the day following the
date fixed for the determination of stockholders entitled to receive such
distribution.
<PAGE>

                                                                              13

          (5)  In case at any time after the date of the issuance of the
Securities, the Company shall, by dividend or otherwise, make a distribution to
all holders of its Common Stock consisting exclusively of cash (excluding any
cash that is distributed upon a merger or consolidation to which Section 1607
applies or as part of a distribution referred to in paragraph (4) of this
Section) in an aggregate amount that, combined together with:

     (A)  the aggregate amount of any other distributions to all holders of its
          Common Stock made exclusively in cash within the 12 months preceding
          the date of payment of such distribution and in respect of which no
          adjustment pursuant to this paragraph (5) has been made, and

     (B)  the aggregate of any cash plus the fair market value (as determined by
          the Board of Directors, whose determination shall be conclusive and
          described in a Board Resolution) of consideration payable in respect
          of any tender offer by the Company or any of its Subsidiaries for all
          or any portion of the Common Stock of the Company concluded within the
          12 months preceding the date of payment of such distribution and in
          respect of which no adjustment pursuant to paragraph (6) of this
          Section has been made,

          (the amount of such cash distribution together with the amounts
described in clauses (A) and (B) above being referred to herein as the
"Aggregate Cash Distribution Amount") exceeds 10% of the product of (I) the
Average Current Market Price per share on the date for the determination of
holders of shares of Common Stock of the Company entitled to receive such cash
distribution, times (II) the number of shares of Common Stock of the Company
outstanding on such date (the amount by which the Aggregate Cash Distribution
Amount exceeds 10% of the product of the amounts described in clauses (I) and
(II) above being referred to herein as the "Excess Amount"), then, and in each
such case, immediately after the close of business on such date for
determination, the Conversion Rate shall be increased in accordance with the
following formula:

                    AC =   CR  /  M - (EA/O)
                                  ----------
                                      M

Where:

          AC = the adjusted Conversion Rate.

          CR = the Conversion Rate in effect immediately prior to the close of
          business on the date fixed for determination of the stockholders
          entitled to receive the distribution.

          M = the Average Current Market Price per share (determined as provided
          in paragraph (8) of this Section) on the date fixed for determination
          of the stockholders entitled to receive the distribution.

          EA = the Excess Amount.

          O = the number of shares of Common Stock of the Company outstanding on
          the date fixed for determination of the stockholders entitled to
          receive the distribution.
<PAGE>

                                                                              14

          (6)  In case at any time after the date of the issuance of the
Securities, a tender offer made by the Company or any Subsidiary for all or any
portion of the Common Stock of the Company shall expire and such tender offer
(as amended upon the expiration thereof) shall require the payment to
stockholders (based on the acceptance (up to any maximum specified in the terms
of the tender offer) of Purchased Shares (as defined below)) of an aggregate
consideration having a fair market value (as determined by the Board of
Directors, whose determination shall be conclusive and described in a Board
Resolution) that combined together with:

     (A)  the aggregate of the cash plus the fair market value (as determined by
          the Board of Directors, whose determination shall be conclusive and
          described in a Board Resolution), as of the expiration of such tender
          offer, of consideration payable in respect of any other tender offer,
          by the Company or any Subsidiary for all or any portion of the Common
          Stock of the Company expiring within the 12 months preceding the
          expiration of such tender offer and in respect of which no adjustment
          pursuant to this paragraph (6) has been made, and

     (B)  the aggregate amount of any distributions to all holders of the
          Company's Common Stock made exclusively in cash within 12 months
          preceding the expiration of such tender offer and in respect of which
          no adjustment pursuant to paragraph (5) of this Section has been made,

exceeds 10% of the product of (I) the Average Current Market Price per share
(determined as provided in paragraph (8) of this Section) as of the last time
(the "Tender Expiration Time") tenders could have been made pursuant to such
tender offer (as it may be amended), times (II) the number of shares of Common
Stock of the Company outstanding (including any tendered shares) on the Tender
Expiration Time, then, and in each such case, immediately prior to the opening
of business on the day after the date of the Tender Expiration Time, the
Conversion Rate shall be increased in accordance with the following formula:

                         AC = CR  /  (M x O) - C
                                     ------------
                                     M x (O - TS)

Where:

          AC = the adjusted Conversion Rate.

          CR = the Conversion Rate immediately prior to close of  business on
          the date of the Tender Expiration Time.

          M = the Average Current Market Price per share (determined as provided
          in paragraph (8) of this Section) on the date of the Tender Expiration
          Time.

          O = the number of shares of Common Stock of the Company outstanding
          (including any tendered shares) on the Tender Expiration Time.

          C = the amount of cash plus the fair market value (as determined by
          the Board of Directors, whose determination shall be conclusive and
<PAGE>

                                                                              15

          described in a Board Resolution) of the aggregate consideration
          payable to stockholders based on the acceptance (up to any maximum
          specified in the terms of the tender offer) of Purchased Shares (as
          defined below).

          TS = the number of all shares validly tendered and not withdrawn as of
          the Tender Expiration Time (the shares deemed so accepted up to any
          such maximum, being referred to as the "Purchased Shares").

          (7)  The reclassification of Common Stock of the Company into
securities including securities other than Common Stock of the Company (other
than any reclassification upon a consolidation or merger to which Section 1607
applies) shall be deemed to involve (a) a distribution of such securities other
than Common Stock of the Company to all holders of Common Stock of the Company
(and the effective date of such reclassification shall be deemed to be "the date
fixed for the determination of stockholders entitled to receive such
distribution" and "the date fixed for such determination" within the meaning of
paragraph (4) of this Section), and (b) a subdivision or combination, as the
case may be, of the number of shares of Common Stock of the Company outstanding
immediately prior to such reclassification into the number of shares of Common
Stock of the Company outstanding immediately thereafter (and the effective date
of such reclassification shall be deemed to be "the day upon which such
subdivision becomes effective" or "the day upon which such combination becomes
effective", as the case may be, and "the day upon which such subdivision or
combination becomes effective" within the meaning of paragraph (3) of this
Section).

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

          (9)  No adjustment in the Conversion Rate shall be required unless
such adjustment (plus any adjustments not previously made by reason of this
paragraph (9)) would require an increase or decrease of at least 1% in such
price; provided, however, that any adjustments which by reason of this paragraph
       --------  -------
(9) are not required to be made shall be carried forward and taken into account
in any subsequent adjustment. All calculations under this paragraph (9) shall be
made to the nearest cent.

          (10) The Company may make such increases in the Conversion Rate, in
addition to those required by this Section, as it considers to be advisable in
order to avoid or diminish any income tax to any holders of shares of Common
Stock of the Company resulting from any dividend or distribution of stock or
issuance of rights or warrants to purchase or subscribe for stock or from any
event treated as such (i) for federal income tax purposes or (ii) for any other
reasons relating to taxes.

          (11) To the extent permitted by applicable law, the Company from time
to time may increase the Conversion Rate by any amount for any period of time if
the period
<PAGE>

                                                                              16

is at least 20 days, the increase is irrevocable during such period, and the
Board of Directors shall have made a determination that such increase would be
in the best interests of the Company, which determination shall be conclusive;
provided, however, that no such increase shall be taken into account for
purposes of determining whether the Current Market Price for any five Trading
Days within the period of 10 Trading Days (as determined pursuant to the
definition of Change of Control) exceeds the Conversion Price by 105% in
connection with an event which would otherwise be a "Change of Control" or
whether the Current Market Price for 20 Trading Days during a period of 30
consecutive Trading Days (as determined pursuant to Section 6.1 or 7.1 hereof,
as applicable exceeds the Conversion Price by (a) the triggering percentages (as
specified in Section 6.1(a) hereof) in connection with a provisional redemption
or (b) 140% in connection with an event which would otherwise allow the Company
to cause the conversion rights of Holders of Securities to expire. Whenever the
Conversion Rate is increased pursuant to the preceding sentence, the Company
shall give notice of the increase to the Holders in the manner provided in
Section 106 at least 15 days prior to the date the increased Conversion Rate
takes effect, and such notice shall state the increased Conversion Rate and the
period during which it will be in effect.

          (12) Whenever the Conversion Rate is adjusted, as herein provided,
the Company shall promptly file with the Trustee, at the Corporate Trust Office
of the Trustee, and with the office or agency maintained by the Company for the
conversion of Securities of such series pursuant to Section 1002, an Officers'
Certificate, setting forth the conversion price after such adjustment and
setting forth a brief statement of the facts requiring such adjustment, which
certificate shall be conclusive evidence of the correctness of such adjustment.
Neither the Trustee nor any conversion agent shall be under any duty or
responsibility with respect to any such certificate or any facts or computations
set forth therein, except to exhibit said certificate from time to time to any
Holder of a Security desiring to inspect the same.  The Company shall promptly
cause a notice setting forth the adjusted conversion price to be mailed to the
Holders of Securities, as their names and addresses appear upon the Security
Register of the Company.

          (13) In any case in which this Section 1605 provides that an
adjustment shall become effective immediately after a record date for an event,
the Company may defer until the occurrence of such event (y) issuing to the
Holder of any Security converted after such record date and before the
occurrence of such event the additional shares of the Common Stock of the
Company issuable upon such conversion by reason of the adjustment required by
such event over and above the Common Stock of the Company issuable upon such
conversion before giving effect to such adjustment and (z) paying to such Holder
any amount in cash in lieu of any fractional share of Common Stock of the
Company pursuant to Section 1606 of the Indenture.

          (b)  Section 1606 is hereby amended with respect to the Securities by
deleting the last sentence thereof in its entirety and substituting the
following in its place:

     "Instead of a fraction of a share of Common Stock of the Company which
     would otherwise be issuable upon conversion of any Security or Securities
     (or specified portions thereof), the Company shall pay a cash adjustment
     (computed to the nearest cent, with one-half cent being rounded upward) in
     respect of such fraction of a share in an amount equal to the same
     fractional interest of the Current Market
<PAGE>

                                                                              17

     Price of the Common Stock of the Company on the Trading Day next preceding
     the day of conversion."

          (c)  Section 1607 is amended by adding the following to the end of the
first sentence thereof:

     ", assuming (i) such holder of Common Stock of the Company failed to
     exercise his or her rights of election, if any, as to the kind or amount of
     shares of stock and other securities and property, including cash,
     receivable upon such consolidation, merger, sale or transfer (provided that
     if the kind or amount of shares of stock and other securities and property,
     including cash, receivable upon such consolidation, merger, sale or
     transfer is not the same for each share of Common Stock of the Company held
     immediately prior to such consolidation, merger, sale or transfer and in
     respect of which such rights of election shall not have been exercised
     ("non-electing share"), then for the purpose of this Section the kind and
     amount of shares of stock and other securities and property, including
     cash, receivable upon such consolidation, merger, sale or transfer by each
     non-electing share shall be deemed to be the kind and amount so receivable
     per share by a plurality of non-electing shares), and (ii) the Securities
     were convertible at the time of such consolidation, merger, sale or
     transfer at the initial Conversion Rate specified in the supplemental
     indenture establishing such Securities, as adjusted, if applicable, in
     accordance with the terms of such supplemental indenture."

          (d)  Section 1608 is amended with respect to the Securities by
deleting the word "or" from the end of clause (c) thereof and adding the
following immediately after clause (d) thereof:

                    "(e)  the Company or a Subsidiary shall take any other
          action that would require an adjustment to the Conversion Rate
          pursuant to Section 1605; or

                    (f)   the Company shall take any action that would require a
          supplemental indenture pursuant to Section 1607;"
<PAGE>

                                                                              18

                                 ARTICLE THREE

               CONSOLIDATION, MERGER, SALE, LEASE OR CONVEYANCE

          SECTION 3.1.  AMENDMENTS TO ARTICLE EIGHT.  Section 801 of the
                        ----------------------------
Indenture is amended in its entirety with respect to the Securities to read as
follows:

          The Company may not consolidate with or merge into any other Person or
convey, transfer, sell or lease its properties and assets substantially as an
entirety to any
<PAGE>

                                                                              19

Person, and the Company shall not permit any Person to consolidate with or merge
into the Company or convey, transfer, sell or lease such Person's properties and
assets substantially as an entirety to the Company, unless:

          (a)  the Person formed by such consolidation or into or with which the
     Company is merged or the Person to which the properties and assets of the
     Company are so conveyed, transferred, sold or leased, is a corporation,
     limited liability company, partnership or trust organized and existing
     under the laws of the United States, any State thereof or the District of
     Columbia and, if other than the Company, shall expressly assume the due and
     punctual payment of the principal of and, premium, if any, and interest on
     the Securities and the performance of the other covenants of the Company
     under the Indenture, and

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


                                 ARTICLE FOUR

                                  DEFEASANCE

          SECTION 4.1.  DEFEASANCE APPLICABLE TO SECURITIES. Pursuant to Section
                        ------------------------------------
301(19) and Section 1401 of the Indenture, the Company will have the option of
defeasance of the Securities under Section 1402 and 1403 of the Indenture upon
the terms and conditions contained in Article Fourteen of the Indenture, as
amended by this Second Supplemental Indenture; provided, however, that the
                                               --------  -------
Company's option of covenant defeasance, as described in Section 1403 of the
Indenture, shall be limited to defeasance of its obligations under Article Eight
of this Second Supplemental Indenture.

          SECTION 4.2.  AMENDMENTS TO ARTICLE FOURTEEN.
                        -------------------------------

          (a)  Section 1404 is hereby amended with respect to the Securities by
deleting the period from the end of clause (b) thereof and adding the following
thereto:

     ", shall not be prohibited by Article Seventeen, and shall be permitted by
     the terms of all Senior Indebtedness."

          (b)  Section 1404 is hereby further amended by deleting "91st" in
clause (c) thereof and substituting "123rd" in its place.

          (c)  Section 1405 is hereby amended by adding the following to the end
of the first paragraph thereof:

     "Money and securities so held in trust are not subject to Article Seventeen
     of the Indenture."


                                 ARTICLE FIVE

                               EVENTS OF DEFAULT
<PAGE>

                                                                              20

          SECTION 5.1.  AMENDMENTS TO SECTION 501.
                        --------------------------

          (a)  Clause 5 of Section 501 of the Indenture is amended in its
entirety with respect to the Securities to read as follows:

          "(5) default under the terms of any instrument evidencing or securing
     Indebtedness of the Company or any Restricted Subsidiary having an
     outstanding principal amount of not less than $25,000,000 or its foreign
     currency equivalent at the time which default results in the acceleration
     of the payment of such Indebtedness or constitutes the failure to pay such
     Indebtedness when due (after expiration of any applicable grace period);
     or".

          (b)  Clause 6 of Section 501 of the Indenture is amended in its
entirety with respect to the Securities to read as follows:

          "(6) the institution by the Company or any Significant Subsidiary of
     proceedings to be adjudicated a bankrupt or insolvent, or the consent by it
     to the institution of bankruptcy or insolvency proceedings against it, or
     the filing by it of a petition or answer or consent seeking reorganization
     or relief under the Federal Bankruptcy Code or any other applicable
     federal, state or foreign law, or the consent by it to the filing of any
     such petition or to the appointment of a receiver, liquidator, assignee,
     trustee, custodian or sequestrator (or other similar official) of the
     Company or any Significant Subsidiary or of any substantial part of its
     Property, or the making by it of an assignment for the benefit of
     creditors, or the admission by it in writing of its inability to pay its
     debts generally as they become due; or"

          (c)  Clause 7 of Section 501 of the Indenture is amended in its
entirety with respect to the Securities to read as follows:

          "(7) the entry of a decree or order by a court having jurisdiction in
     the premises adjudging the Company or any Significant Subsidiary a bankrupt
     or insolvent, or approving as properly filed a petition seeking
     reorganization, arrangement, adjustment or composition of or in respect of
     the Company or any Significant Subsidiary under the Federal Bankruptcy Code
     or any other applicable federal, state or foreign law, or appointing a
     receiver, liquidator, assignee, trustee, custodian or sequestrator (or
     other similar official) of the Company or any Significant Subsidiary or of
     any substantial part of its Property, or ordering the winding up or
     liquidation of its affairs, and the continuance of any such decree or order
     unstayed and in effect for a period of 60 consecutive days."

          SECTION 5.2.   ADDITIONAL EVENTS OF DEFAULT.  Pursuant to Section
                         -----------------------------
301(15) of the Indenture, so long as any of the Securities are Outstanding, each
of the following events shall be an Event of Default with respect to the
Securities, in addition to the Events of Default contained in Section 501 of the
Indenture, as amended hereby:

          (1)  failure to pay when due the Purchase Price of any Securities
required to be repurchased pursuant to Article Eight of this Second Supplemental
Indenture whether or not an Offer to Purchase is prohibited by Article Seventeen
of the Indenture, as amended hereby; or
<PAGE>

                                                                              21

          (2)  failure to perform or comply with Article Eight of the Indenture,
as amended hereby; or

          (3)  the rendering of any judgment or judgments for the payment of
money in an aggregate amount in excess of $25 million or its foreign currency
equivalent at the time that shall be rendered against the Company or any
Restricted Subsidiary and that shall not be waived, satisfied or discharged for
any period of 45 consecutive days during which a stay of enforcement shall not
be in effect.

          SECTION 5.3.  NOTICE OF DEFAULT OR EVENT OF DEFAULT. The Company shall
                        ---------------------------------------
deliver to the Trustee, as soon as reasonably practicable and in any event
within 30 days after an executive officer of Company becomes aware of the
occurrence of any Event of Default or any event which, with notice or the lapse
of time or both, would constitute an Event of Default, an Officers' Certificate
setting forth the details of such Event of Default or Default and the action
which the Company proposes to take with respect thereto.


                                  ARTICLE SIX

                            PROVISIONAL REDEMPTION

          Pursuant to Section 301(6) of the Indenture, so long as any of the
Securities are Outstanding, the following provisions shall be applicable to the
Securities:

          SECTION 6.1.  PROVISIONAL REDEMPTION.
                        -----------------------

          (a)  At any time or from time to time prior to March 18, 2003, the
Company may, at its option, redeem the Securities (a "Provisional Redemption"),
in whole or in part, at the following Redemption Prices, in each case plus
accrued and unpaid interest, if any, to the date of such redemption (herein
called the "Provisional Redemption Date"), if the Current Market Price of Common
Stock of the Company equals or exceeds the following trigger percentages of the
prevailing Conversion Price then in effect for at least 20 Trading Days within
any period of 30 consecutive Trading Days, including the last day of such period
(herein called the"Redemption Condition"), if called for redemption during any
of the periods beginning and ending as set forth below.

<TABLE>
<CAPTION>
                                                        Trigger     Redemption
Year                                                  Percentage       Price
-----                                                ------------  ------------
<S>                                                  <C>           <C>
February 29, 2000 through March 14, 2001...........           170%      106.00%
March 15, 2001 through March 14, 2002..............           160%      105.40%
March 15, 2002 through March 17, 2003..............           150%      104.80%
</TABLE>

          (b)  Upon any Provisional Redemption, the Company will make an
additional payment in cash (herein called the "Make-Whole Payment") with respect
to the Securities converted into Common Stock of the Company between the date
notice of redemption was given (herein called the "Notice Date") and the
Provisional Redemption Date.  The Make-Whole Payment will be equal to the
present value of the aggregate value
<PAGE>

of the interest payments that would thereafter have been payable on this
Security on each semi-annual interest payment date from the Provisional
Redemption Date through March 17, 2003. The present value will be calculated
using the bond equivalent yield on U.S. Treasury notes or bills having a term
nearest in length to that of the additional period as of the day immediately
preceding the Notice Date.

          (c)  If less than all of the Securities are to be redeemed at any
time, selection of Securities for redemption will be made by the Trustee in
compliance with the requirements of the principal national securities exchange,
if any, on which the Securities are listed, or if the Securities are not so
listed, on a pro rata basis, by lot or by such method as the Trustee shall deem
fair and appropriate, provided that no Securities of $1,000 in principal amount
or less shall be redeemed in part.  A new Security in principal amount equal to
the unredeemed portion thereof will be issued in the name of the Holder thereof
upon cancelation of the original Security.  On and after the redemption date,
interest ceases to accrue on Securities or portions of Securities called for
redemption.

          (d)  In order to redeem any or all of the Securities, the Company must
issue a press release for publication on the Dow Jones News Service (or a
comparable news service) announcing the Provisional Redemption Date prior to the
opening of business on the second Trading Day after any period in which the
Redemption Condition has been met.  The press release shall announce the
Provisional Redemption Date and provide the current Conversion Price of the
Securities and the Current Market Price of the Company Stock of the Company in
each case as of the close of business on the Trading Day next preceding the date
of the press release.

          (e)  Notice of the Provisional Redemption will be given by the Company
to the Holders of the Securities in accordance with Section 106 not more than
four Business Days after the Company issued the press release under paragraph
(d) hereof.  Such notice shall be irrevocable and will specify the Provisional
Redemption Date.

          (f)  The Securities subject to the Provisional Redemption will be
redeemed at the close of business on the Provisional Redemption Date, which will
be a date selected by the Company not less than 30 nor more than 60 days after
the date on which the Company issues the press release under paragraph (d)
hereof.  If any Security is to be redeemed in part only, the notice of
redemption pursuant to paragraph (e) hereof that relates to such Security shall
state the portion of the principal amount thereof to be redeemed.


                                 ARTICLE SEVEN

                        EXPIRATION OF CONVERSION RIGHTS

          Pursuant to Section 301(25) of the Indenture, so long as any of the
Securities are Outstanding, the following provisions shall be applicable to the
Securities:

          SECTION 7.1.  EXPIRATION OF CONVERSION RIGHTS.
                        --------------------------------

          (a)  On or after March 18, 2003, the Company may, at its option, cause
the conversion rights of Holders of Securities to expire. The Company may
exercise this option only if the Current Market Price of the Common Stock of the
Company exceeds
<PAGE>

                                                                              23

140% of the Conversion Price for at least 20 Trading Days within any period of
30 consecutive Trading Days, including the last Trading Day of such period
(herein called the "Expiration Condition").

          (b)  In order to exercise its option to cause the conversion rights of
Holders of Securities to expire, the Company must issue a press release for
publication on the Dow Jones News Service (or a comparable news service)
announcing the conversion expiration date (the "Conversion Expiration Date")
prior to the opening of business on the second Trading Day after the Expiration
Condition has been met, but in no event prior to March 18, 2003.  The press
release shall announce the Conversion Expiration Date and provide the current
Conversion Price of the Securities and the Current Market Price of the Common
Stock of the Company, in each case as of the close of business on the Trading
Day next preceding the date of the press release.

          (c)  Notice of the expiration of conversion rights will be given by
the Company to the Holders of the Securities in accordance with Section 106 not
more than four Business Days after the Company issued the press release under
paragraph (b) hereof.  Such notice shall be irrevocable and shall specify the
Conversion Expiration Date.

          (d)  Conversion rights will terminate at the close of business on the
Conversion Expiration Date which will be a date selected by the Company not less
than 30 nor more than 60 days after the date on which the Company issues the
press release under paragraph (b) hereof announcing its intention to terminate
conversion rights of the Securities.


                                 ARTICLE EIGHT

                          SUBORDINATION OF SECURITIES

          Pursuant to Section 301(25) of the Indenture, and in addition to the
other provisions contained in Article Seventeen of the Indenture (which shall be
applicable as amended hereby to the Securities in all respects), so long as any
of the Securities are Outstanding, the following provisions shall be applicable
to the Securities:

          SECTION 8.1.  AMENDMENT OF SECTION 1701.  (a)  Section 1701 is hereby
                        --------------------------
amended by relettering clause (c) in the second paragraph thereof to be clause
(b) and by deleting the following from the second paragraph thereof:

          "(b) that a default shall have occurred and be continuing with respect
to the payment of principal of (or premium, if any) or interest on or any
Additional Amounts payable in respect of any Senior Indebtedness, or"

          (b)  Section 1701(1) is hereby amended by deleting the words "or (b)"
therefrom.
<PAGE>

                                                                              24

          SECTION 8.2.   NO PAYMENT IN CERTAIN CIRCUMSTANCES.  (a) No payment
                         ------------------------------------
shall be made with respect to the principal of, or premium, if any, or interest
on the Securities (including, but not limited to, the Purchase Price with
respect to Securities submitted for repurchase in accordance with Article Eight
hereof), if:

          (i) a default in the payment of principal, premium, if any, or
interest (including a default under any repurchase or redemption obligation) or
other amounts with respect to any Senior Indebtedness occurs and is continuing
unless and until such default shall have been cured or waived or shall have
ceased to exist; or

          (ii) a default, other than a payment default, on any Senior
Indebtedness occurs and is continuing that then permits holders of such Senior
Indebtedness to accelerate (with notice, lapse of time or both) its maturity
unless and until such default shall have been cured or waived or shall have
ceased to exist if the maturity of such Senior Indebtedness has not been
accelerated.


                                 ARTICLE NINE

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

          Pursuant to Section 301(7) of the Indenture and in substitution of the
terms of Article Thirteen of the Indenture, so long as any of the Securities are
Outstanding, the following provisions shall be applicable to the Securities:

          SECTION 9.1.  RIGHT TO REQUIRE REPURCHASE.
                        ----------------------------

          (a)  Upon the occurrence of  a Change in Control, each Holder shall
have the right, at the Holder's option, but subject to the provisions of Section
9.2. hereof, to require the Company to repurchase all of such Holder's
Securities or any portion of the principal amount thereof that is equal to
$5,000 or any integral multiple of $1,000 in excess thereof (provided that no
single Security may be repurchased in part unless the portion of the principal
amount of such Security to be Outstanding after such repurchase is equal to
$1,000 or integral multiples of $1,000 in excess thereof), in accordance with
the procedures set forth in this Section 9.1 and this Second Supplemental
Indenture.  The First Supplemental Indenture, 9-1/8% Senior Notes Indenture, the
10-1/2% Senior Discount Notes Indenture, the Dollar Denominated Senior Notes
Indenture and the Euro Denominated Senior Notes Indenture each require that such
Indebtedness be repurchased upon the occurrence of certain of the events that
would constitute a Change of Control. Other future Indebtedness of the Company
may contain prohibitions of certain events which would constitute a Change of
Control or require such Indebtedness to be repurchased upon a Change of Control.
To the extent other Indebtedness of the Company is both subject to similar
repurchase obligations in the event of a Change of Control and ranks senior in
right of payment to the Securities, the Company will repurchase such
Indebtedness required to be repurchased pursuant to the terms thereof before
repurchasing any of the Securities.

          (b)  Within 30 days of the occurrence of a Change of Control, the
Company will be required to make an Offer to Purchase all Outstanding Securities
at a price, subject to next sentence, in cash equal to 100% of the principal
amount of the
<PAGE>

                                                                              25

Securities on the Purchase Date, plus accrued and unpaid interest (if any) to
such Purchase Date (subject to the right of Holders of record on the relevant
record date to receive interest due on the relevant Interest Payment Date). At
the option of the Company, the Purchase Price may be paid in cash or, subject to
the fulfillment by the Company of the conditions set forth Section 9.2 hereof,
by delivery of shares of Common Stock of the Company having a fair market value
equal to the Purchase Price.

          (c)  The Company and the Trustee shall perform their respective
obligations for the Offer to Purchase as specified in the Offer. Prior to the
Purchase Date, the Company shall (i) accept for payment Securities or portions
thereof tendered pursuant to the Offer, (ii) irrevocably deposit with the Paying
Agent (or, if the Company is acting as its own Paying Agent, segregate and hold
in trust as provided in Section 1003) cash or shares of Common Stock of the
Company, as provided below, sufficient to pay the Purchase Price of all
Securities or portions thereof so accepted (provided that such deposit may be
made no later than 11:00 A.M. New York City time on the Purchase Date if the
Company elects) and (iii) deliver or cause to be delivered to the Trustee all
Securities so accepted together with an Officers' Certificate stating the
Securities or portions thereof accepted for payment by the Company. The Paying
Agent shall promptly mail or deliver to Holders of Securities so accepted
payment or shares of Common Stock of the Company in an amount equal to the
Purchase Price, and the Trustee shall promptly authenticate and mail or deliver
to such Holders a new Security or Securities equal in principal amount to any
unpurchased portion of the principal amount of the Security surrendered as
requested by the Holder. Any Security not accepted for payment shall be promptly
mailed or delivered by the Company to the Holder thereof. In the event that the
aggregate Purchase Price is less than the amount delivered by the Company to the
Trustee or the Paying Agent, the Trustee or the Paying Agent, as the case may
be, shall deliver the excess to the Company immediately after the Purchase Date.

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

          (e)  No fractions of shares shall be issued upon repurchase of
Securities. If more than one Security shall be repurchased from the same Holder
and the Purchase Price shall be payable in shares of Common Stock of the
Company, the number of full shares which shall be issuable upon such repurchase
shall be computed on the basis of the aggregate principal amount of the
Securities so repurchased. Instead of any fractional share of Common Stock of
the Company which would otherwise be issuable on the repurchase of any Security
or Securities, the Company will deliver to the applicable Holder its check for
the current market value of such fractional share. The current market value of a
fraction of a share is determined by multiplying the Current Market Price of a
<PAGE>

                                                                              26

full share on the Trading Day immediately preceding the Purchase Date by the
fraction, and rounding the result to the nearest cent.

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

          (g)  Whenever in this Second Supplemental Indenture, Exhibit A hereto
of the Indenture (including Article One hereof and Sections 201, 501(1) and 508
of the Indenture) there is a reference, in any context, to the principal of any
Security as of any time, such reference shall be deemed to include reference to
the Purchase Price payable in respect of such Security to the extent that such
Purchase Price is, was or would be so payable at such time, and express mention
of the Purchase Price in any provision of this Second Supplemental Indenture
shall not be construed as excluding the Purchase Price in those provisions of
this Second Supplemental Indenture when such express mention is not made;
provided, however, that for the purposes of Article Eight such reference shall
--------  -------
be deemed to include reference to the Purchase Price only to the extent the
Purchase Price is payable in cash.

          (h)  The Company shall not be required to make an Offer to Purchase
upon a Change of Control if a third party makes the Offer to Purchase in the
manner, at the times and otherwise in compliance with the requirements set forth
in the Indenture applicable to an Offer to Purchase made by the Company and
purchases all Securities validly tendered and not withdrawn under such Offer to
Purchase.

          (i)  In the event that the Company makes an Offer to Purchase, the
Company shall comply with any applicable securities laws and regulations,
including any applicable requirements of Section 14(e) of, and Rule 14e-1 under,
the Exchange Act. To the extent that the provisions of any securities laws or
regulations conflict with provisions of this Section, the Company shall comply
with the applicable securities laws and regulations and shall not be deemed to
have breached its obligations under this Section by virtue thereof.

          SECTION 9.2.  CONDITIONS TO THE COMPANY'S ELECTION TO PAY THE
                        -----------------------------------------------
REPURCHASE PRICE IN COMMON STOCK OF THE COMPANY.  The Company may elect to pay
------------------------------------------------
the Purchase Price by delivery of shares of Common Stock of the Company pursuant
to Section 9.1 if:

          (1)  The shares of Common Stock of the Company deliverable in payment
of the Purchase Price shall have a fair market value as of the Purchase Date of
not less than the Purchase Price. For purposes of Section 9.1 and this Section
9.2, the fair market value of shares of Common Stock of the Company shall be
determined by the Company and shall be equal to 95% of the average of the
Current Market Price of the Common
<PAGE>

                                                                              27

Stock of the Company for the five consecutive Trading Days immediately preceding
and including the third Trading Day prior to the Purchase Date;

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

          (3)  The shares of Common Stock of the Company to be issued upon
repurchase of Securities hereunder are, or shall have been, approved for listing
on the Nasdaq National Market or the New York Stock Exchange or listed on
another national securities exchange, in any case, prior to the Purchase Date;
and

          (4)  All shares of Common Stock of the Company which may be issued
upon repurchase of Securities will be issued out of the Company's authorized but
unissued Common Stock and, will upon issue, be duly and validly issued and fully
paid and non-assessable and free of any preemptive or similar rights.

          If all of the conditions set forth in this Section 9.2 are not
satisfied in accordance with the terms hereof, the Purchase Price shall be paid
by the Company only in cash.

          SECTION 9.3.  CONSOLIDATION, MERGER, ETC.  In the case of any
                        ---------------------------
consolidation, conveyance, sale, transfer or lease of all or substantially all
of the assets of the Company to which Section 1607 of the Indenture applies, in
which the Common Stock of the Company is changed or exchanged as a result into
the right to receive shares of stock and other securities or property or assets
(including cash) which includes shares of Common Stock of the Company or common
stock of another Person that are, or upon issuance will be, traded on a United
States national securities exchange or approved for trading on an established
automated over-the-counter trading market in the United States and such shares
constitute at the time such change or exchange becomes effective in excess of
50% of the aggregate fair market value of such shares of stock and other
securities, property and assets (including cash) (as determined by the Company,
which determination shall be conclusive and binding), then the Person formed by
such consolidation or resulting from such merger or combination or which
acquires the properties or assets (including cash) of the Company, as the case
may be, shall execute and deliver to the Trustee a supplemental indenture (which
shall comply with the Trust Indenture Act as in force at the date of execution
of such supplemental indenture) modifying the provisions of this Second
Supplemental Indenture relating to the right of Holders to cause the Company to
repurchase the Securities following a Change in Control, including without
limitation the applicable provisions of this Article Eight and the definitions
of the Common Stock and Change in Control, as appropriate, and such other
related definitions set forth herein and in the Indenture as determined in good
faith by the Company (which determination shall be conclusive and binding), to
make such provisions apply in the event of a subsequent Change of Control to the
common stock and
<PAGE>

                                                                              28

the issuer thereof if different from the Company and Common Stock of the Company
(in lieu of the Company and the Common Stock of the Company).


                                  ARTICLE TEN

                            SUPPLEMENTAL INDENTURES

          SECTION 10.1.  AMENDMENTS TO ARTICLE TEN.  (a)  Section 901 is hereby
                         --------------------------
amended with respect to the Securities by deleting the word "or" from the end of
clause (9) thereof, deleting the "." from the end of clause (10) thereof and
substituting a ";" in its place and by adding the following to the end thereof:

          (11) to add guarantees with respect to the Securities; or

          (12) to comply with any requirements of the Commission in connection
     with qualifying, or maintaining the qualification of, the Indenture under
     the Securities Act or the TIA.

          (b)  Section 902 is hereby amended by inserting "at any time after a
Change of Control has occurred" after the words "Section 504, or" in clause (1)
thereof and by adding the following to the end of the first paragraph of Section
902:

          (6)  modify Article Sixteen or Article Seventeen of the Indenture, as
     amended, or Article Six or Article Seven of this Second Supplemental
     Indenture in a manner adverse to the Holders; and

          (7)  reduce the premium payable upon the redemption of any Security or
     change the time at which any Security may be redeemed pursuant to Section
     6.1 hereof.


                                ARTICLE ELEVEN

                       MEETINGS OF HOLDERS OF SECURITIES

          SECTION 11.1.  AMENDMENTS TO ARTICLE FIFTEEN.  Section 1504 of the
                         ------------------------------
Indenture is amended with respect to the Securities by adding the following to
the end of the first paragraph thereof:

     "Subject to the proviso in the first sentence of this paragraph, the
     Persons entitled to vote 25% of the principal amount of the Outstanding
     Securities shall constitute a quorum for a reconvened meeting previously
     adjourned for lack of a quorum.
<PAGE>

                                                                              29

                                ARTICLE TWELVE

                                 MISCELLANEOUS

          SECTION 12.1.  APPLICATION OF SECOND SUPPLEMENTAL INDENTURE. Each and
                         ---------------------------------------------
every term and condition contained in this Second Supplemental Indenture that
modifies, amends or supplements the terms and conditions of the Indenture shall
apply only to the Securities created hereby and not to any future series of
Securities established under the Indenture.

          SECTION 12.2.  BENEFITS OF SECOND SUPPLEMENTAL INDENTURE.  Nothing
                         ------------------------------------------
contained in this Second Supplemental Indenture shall or shall be construed to
confer upon any person other than a Holder of the Securities, the Company and
the Trustee any right or interest to avail itself or himself, as the case may
be, of any benefit under any provision of the Indenture or this Second
Supplemental Indenture, except for Holders of Senior Indebtedness as provided in
Article Seven hereof.

          SECTION 12.3.  EFFECTIVE DATE.  This Second Supplemental Indenture
                         ---------------
shall be effective as of the date first above written and upon the execution and
delivery hereof by each of the parties hereto.

          SECTION 12.4.  GOVERNING LAW.  This Second Supplemental Indenture
                         --------------
shall be governed by, and construed in accordance with, the laws of the State of
New York.
<PAGE>

                                                                              30

          SECTION 12.5.  COUNTERPARTS.  This Second Supplemental Indenture may
                         -------------
be executed in any number of counterparts, each of which so executed shall be
deemed to be an original, but all such counterparts shall together constitute
but one and the same instrument.


          IN WITNESS WHEREOF, the parties hereto have caused this Second
Supplemental Indenture to be duly executed by their respective officers hereunto
duly authorized, all as of the day and year first above written.


                                   LEVEL 3 COMMUNICATIONS, INC.


                                   By: /s/ Thomas C. Stortz
                                       ___________________________
                                       Name: Thomas C. Stortz
                                       Title: Senior Vice President



                                   THE BANK OF NEW YORK, as Trustee


                                   By: /s/ Van K. Brown
                                       ____________________________
                                       Name: Van K. Brown
                                       Title: Assistant Vice President
<PAGE>

                                   EXHIBIT A

                           Form of Face of Security
                           ------------------------

     [If a Global Security, then insert:]  THIS SECURITY IS A GLOBAL SECURITY
WITHIN THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN
THE NAME OF A DEPOSITORY OR A NOMINEE OF A DEPOSITORY OR A SUCCESSOR DEPOSITORY.
THIS SECURITY IS NOT EXCHANGEABLE FOR SECURITIES REGISTERED IN THE NAME OF A
PERSON OTHER THAN THE DEPOSITORY OR ITS NOMINEE EXCEPT IN THE LIMITED
CIRCUMSTANCES DESCRIBED IN THE INDENTURE, AND NO TRANSFER OF THIS SECURITY
(OTHER THAN A TRANSFER OF THIS SECURITY AS A WHOLE BY THE DEPOSITORY TO A
NOMINEE OF THE DEPOSITORY OR BY A NOMINEE OF THE DEPOSITORY TO THE DEPOSITORY OR
ANOTHER NOMINEE OF THE DEPOSITORY) MAY BE REGISTERED EXCEPT IN THE LIMITED
CIRCUMSTANCES DESCRIBED IN THE INDENTURE.

          [If a Global Security, then insert:]  UNLESS THIS CERTIFICATE IS
PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW
YORK CORPORATION ("DTC"), TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER
ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER,
PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS
WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST
HEREIN.
<PAGE>

                         LEVEL 3 COMMUNICATIONS, INC.

                   6% Convertible Subordinated Note Due 2010

                                                             CUSIP No. 52729NAS9
                                                                       ---------
No.       [if a Global security, insert: up to] $

     Level 3 Communications, Inc., a Delaware corporation (herein called the
"Company", which term includes any successor Person under the Indenture
hereinafter referred to), for value received, hereby promises to pay to
_____________, or registered assigns, the principal sum of [if a Global
Security, then insert: up to] _________ Dollars [if a Global Security, then
insert: (the outstanding principal amount of which shall be reflected in the
attached Schedule of Increases or Decreases in Global Security and the records
of the Trustee which, taken together with the outstanding principal amounts of
all other Outstanding Securities, shall not exceed $862,500,000 in the aggregate
at any time)] on March 15, 2010, at the office or agency of the Company referred
to below, and to pay interest thereon, in cash in arrears semiannually on March
15 and September 15 in each year, with payment commencing on September 15, 2000,
and interest accruing from February 29, 2000, or from the most recent Interest
Payment Date to which interest has been paid or duly provided for, at the rate
of 6 % per annum, until the principal amount hereof is paid or duly provided
for. The Company shall pay interest on overdue principal at the rate borne by
this Security, and it shall pay interest on overdue installments of interest at
the same rate to the extent lawful.

     The interest so payable, and punctually paid or duly provided for, on any
Interest Payment Date will, as provided in such Indenture, be paid to the Person
in whose name this Security (or one or more Predecessor Securities) is
registered at the close of business on the Regular Record Date for such
interest, which shall be March 1 or September 1 (whether or not a Business Day),
as the case may be, next preceding such Interest Payment Date. Any such interest
not so punctually paid or duly provided for shall forthwith cease to be payable
to the Holder on such Regular Record Date, and such defaulted interest, and (to
the extent lawful) interest on such defaulted interest at the rate borne by the
Securities, may be paid to the Person in whose name this Security (or one or
more Predecessor Securities) is registered at the close of business on a Special
Record Date for the payment of such Defaulted Interest to be fixed by the
Trustee, notice whereof shall be given to Holders of Securities not less than 10
days prior to such Special Record Date, or may be paid at any time in any other
lawful manner, all as more fully provided in said Indenture. Payment of the
principal of (and premium, if any) and interest on this Security will be made at
the office or agency of the Company maintained for that purpose in The City of
New York, or at such other office or agency of the Company as may be maintained
for such purpose, in such coin or currency of the United States of America as at
the time of payment is legal tender for payment of public and private debts;
provided, however, that payment of interest may be made at the option of the
--------  -------
Company by check mailed to the address of the Person entitled thereto as such
address shall appear on the Security Register.

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

                                      A-2
<PAGE>

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

                                      A-3
<PAGE>

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


Dated:_______________              LEVEL 3 COMMUNICATIONS, INC.

                                   By:
                                        ________________________
                                        Authorized Signatory


Attest:
        ___________________


                                      A-4
<PAGE>

                          Form of Reverse of Security


     This Security is one of a duly authorized issue of securities of the
Company designated as its 6 % Convertible Subordinated Notes Due 2010 (herein
called the "Securities"), limited (except as otherwise provided in the Indenture
referred to below) in aggregate principal amount to $862,500,000, which may be
issued under an indenture (herein called the "Base Indenture") dated as of
September 20, 1999, as supplemented by the Second Supplemental Indenture (the
"Second Supplemental Indenture" and, together with the Base Indenture, the
"Indenture") dated as of February 29, 2000, in each case between the Company and
The Bank of New York, as trustee (herein called the "Trustee", which term
includes any successor trustee under the Indenture), to which Indenture and all
indentures supplemental thereto reference is hereby made for a statement of the
respective rights, limitations of rights, duties, obligations and immunities
thereunder of the Company, the Trustee and the Holders of the Securities, and of
the terms upon which the Securities are, and are to be, authenticated and
delivered.

Provisional Redemption
----------------------

          At any time or from time to time prior to March 18, 2003, the Company
may, at its option, redeem this Security, in whole or in part, at the following
Redemption Prices, in each case plus accrued and unpaid interest, if any, to the
date of such redemption (herein called the "Provisional Redemption Date"), if
the Current Market Price of Common Stock of the Company equals or exceeds the
following trigger percentages of the prevailing Conversion Price then in effect
for at least 20 Trading Days within any period of 30 consecutive Trading Days,
including the last day of such period, if called for redemption during any of
the periods beginning and ending as set forth below.


                                                    Trigger     Redemption
Year                                               Percentage      Price
----                                               ----------   -----------

February 29, 2000 through March 14, 2001               170%      106.00%
March 15, 2001 through March 14, 2002                  160%      105.40%
March 15, 2002 through March 17, 2003                  150%      104.80%


          Upon any provisional redemption, the Company will make an additional
payment in cash (herein called the "Make-Whole Payment") with respect to the
Securities converted into Common Stock of the Company between the date notice of
redemption was given (herein called the "Notice Date") and the Provisional
Redemption Date. The Make-Whole Payment will be equal to the present value of
the aggregate value of the interest payments that would thereafter have been
payable on this Security on each semi-annual interest payment date from the
Provisional Redemption Date through March 17, 2003. The present value will be
calculated using the bond equivalent yield on U.S. Treasury notes or bills
having a term nearest in length to that of the additional period as of the day
immediately preceding the Notice Date.

                                      A-5
<PAGE>

          If less than all of the Securities are to be redeemed at any time,
selection of Securities for redemption will be made by the Trustee in compliance
with the requirements of the principal national securities exchange, if any, on
which the Securities are listed, or if the Securities are not so listed, on a
pro rata basis, by lot or by such method as the Trustee shall deem fair and
appropriate, provided that no Securities of $1,000 in principal amount or less
shall be redeemed in part. A new Security in principal amount equal to the
unredeemed portion thereof will be issued in the name of the Holder thereof upon
cancelation of the original Security. On and after the redemption date, interest
ceases to accrue on Securities or portions of Securities called for redemption.

          In order to redeem any or all of the Securities, the Company must
issue a press release for publication on the Dow Jones News Service (or a
comparable news service) announcing the Provisional Redemption Date prior to the
opening of business on the second Trading Day after any period in which the
condition described above has been met. The press release shall announce the
Provisional Redemption Date and provide the current Conversion Price of the
Securities and the Current Market Price of the Common Stock of the Company in
each case as of the close of business on the Trading Day next preceding the date
of the press release.

          Notice of the provisional redemption will be given by the Company by
first class mail to the Holders of the Securities not more than four business
days after the Company issued the press release. Such notice shall be
irrevocable and will specify the Provisional Redemption Date. The Securities
subject to the provisional redemption will be redeemed at the close of business
on the Provisional Redemption Date, which will be a date selected by the Company
not less than 30 nor more than 60 days after the date on which the Company
issues the press release announcing the provisional redemption. If any Security
is to be redeemed in part only, the notice of redemption that relates to such
Security shall state the portion of the principal amount thereof to be redeemed.

Expiration of Conversion Rights
-------------------------------

     On or after March 18, 2003, the Company may, at its option, cause the
conversion rights of Holders of Securities to expire. The Company may exercise
this option only if the Current Market Price of Common Stock of the Company
exceeds 140% of the prevailing Conversion Price then in effect for at least 20
Trading Days within any period of 30 consecutive Trading Days, including the
last Trading Day of such period. In order to exercise its option to cause the
conversion rights of Holders of Securities to expire, the Company must issue a
press release for publication on the Dow Jones News Service (or a comparable
news service) announcing the Conversion Expiration Date prior to the opening of
business on the second Trading Day after any period in which the Expiration
Condition has been met, but in no event prior to March 18, 2003. The press
release shall announce the Conversion Expiration Date and provide the current
Conversion Price of the Securities and the Current Market Price of the Common
Stock of the Company, in each case as of the close of business on the Trading
Day next preceding the date of the press release.

     Notice of the expiration of conversion rights will be given by the Company
by first class mail to the Holders of the Securities not more than four business
days after the Company issued the press release. Conversion rights will
terminate at the close of business on the Conversion Expiration Date which will
be a date selected by the Company not less than 30 nor more than 60 days after
the date on which the Company

                                      A-6
<PAGE>

issues the press release announcing its intention to terminate conversion rights
of the Securities.

Repurchase at the Option of Holders upon a Change of Control
------------------------------------------------------------

     Upon the occurrence of a Change of Control, the Holder of this Security may
require the Company, subject to certain limitations provided in the Indenture,
to repurchase this Security at a purchase price in cash in an amount equal to
100% of the principal amount thereof, plus accrued and unpaid interest (if any)
to the Purchase Date (subject to the right of Holders of record on the relevant
record date to receive interest due on the relevant interest payment date).

     At the option of the Company, the Purchase Price may be paid in cash or,
subject to the conditions provided in the Indenture, by delivery of shares of
Common Stock of the Company having a fair market value equal to the Purchase
Price. For purposes of this paragraph, the fair market value of shares of Common
Stock of the Company shall be determined by the Company and shall be equal to
95% of the average of the Current Market Price for the five consecutive Trading
Days immediately preceding and including the third Trading Day prior to the
Purchase Date. Whenever in this Security there is a reference, in any context,
to the principal of any Security as of any time, such reference shall be deemed
to include reference to the Purchase Price payable in respect of such Security
to the extent that such Purchase Price is, was or would be so payable at such
time, and express mention of the Purchase Price in any provision of this
Security shall not be construed as excluding the Purchase Price so payable in
those provisions of this Security when such express mention is not made.

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

Conversion Rights
-----------------

     Subject to and upon compliance with the provisions of the Indenture, the
Holder of this Security is entitled, at his or her option, at any time following
the original issue date of the Securities and on or before the close of business
on the Business Day immediately preceding March 15, 2010, or in case the Company
has caused the conversion rights of the Holder hereof to expire or the Holder
hereof has exercised his right to require the Company to repurchase this
Security or such portion hereof, then in respect of this Security until but
(unless the Company defaults in making the payment due upon redemption or
repurchase, as the case may be) not after, the close of business on the
Conversion Expiration Date or the Business Day immediately preceding the
Purchase Date, as the case may be, to convert this Security (or any portion of
the principal amount hereof that is an integral multiple of $1,000, provided
that the unconverted portion of such principal amount is $1,000 or any integral
multiple of $1,000 in excess thereof) into fully paid and nonassessable shares
of Common Stock of the Company at an initial Conversion Rate of 7.416 shares of
Common Stock of the Company for each $1,000 principal amount of Security (or at
the current adjusted Conversion Rate if an adjustment has been made as provided
in the Indenture) by surrender of this Security, duly endorsed or assigned to
the Company or in blank and, in case such surrender shall be made during the
period from the close of business on any Regular Record Date next preceding any
Interest Payment Date to the opening of business on such Interest Payment Date
(except if

                                      A-7
<PAGE>

this Security or portion thereof repurchasable on a Purchase Date or redeemable
on a Provisional Redemption Date and the conversion rights of this Security, or
such portion thereof, would terminate during the period between such Regular
Record Date and the close of business on such Interest Payment Date), also
accompanied by payment in New York Clearing House or other funds acceptable to
the Company of an amount equal to the interest payable on such Interest Payment
Date on the principal amount of this Security then being converted, and also the
conversion notice hereon duly executed, to the Company at the Corporate Trust
Office of the Trustee, or at such other office or agency of the Company, subject
to any laws or regulations applicable thereto and subject to the right of the
Company to terminate the appointment of any Conversion Agent (as defined below)
as may be designated by it for such purpose in the Borough of Manhattan, The
City of New York, or at such other offices or agencies as the Company may
designate (each a "Conversion Agent"), provided, however, that if this Security
or portion hereof is repurchasable on a Purchase Date or redeemable on a
Provisional Redemption Date and the conversion rights of this Security, or such
portion thereof, would terminate during the period between such Regular Record
Date and the close of business on such Interest Payment Date, then the Holder of
this Security on such Regular Record Date will be entitled to receive the
interest accruing on this Security or a portion hereof from the Interest Payment
Date next preceding the date of such conversion to such succeeding Interest
Payment Date and the Holder of this Security who converts this Security or a
portion hereof during such period shall not be required to pay such interest
upon surrender of this Security for conversion. Subject to the provisions of the
preceding sentence and, in the case of a conversion after the close of business
on the Regular Record Date next preceding any Interest Payment Date and on or
before the close of business on such Interest Payment Date, to the right of the
Holder of this Security (or any Predecessor Security of record as of such
Regular Record Date) to receive the related installment of interest to the
extent and under the circumstances provided in the Indenture, no cash payment or
adjustment is to be made on conversion for interest accrued hereon from the
Interest Payment Date next preceding the day of conversion, or for dividends on
the Common Stock of the Company issued on conversion hereof. The Company shall
thereafter deliver to the Holder the fixed number of shares of Common Stock of
the Company (together with any cash adjustment, as provided in the Indenture)
into which this Security is convertible and such delivery will be deemed to
satisfy the Company's obligation to pay the principal amount of this Security.
No fractions of shares or scrip representing fractions of shares will be issued
on conversion, but instead of any fractional interest the Company shall pay a
cash adjustment as provided in the Indenture. The Conversion Rate is subject to
adjustment as provided in the Indenture. In addition, the Indenture provides
that in case of certain consolidations or mergers to which the Company is a
party (other than a consolidation or merger that does not result in any
reclassification, conversion, exchange or cancellation of the Common Stock of
the Company) or the conveyance, transfer, sale or lease of all or substantially
all of the property and assets of the Company, the Indenture shall be amended,
without the consent of any Holders of Securities, so that this Security, if then
Outstanding, will be convertible thereafter, during the period this Security
shall be convertible as specified above, only into the kind and amount of
securities, cash and other property receivable upon such consolidation, merger,
conveyance, transfer, sale or lease by a holder of the number of shares of
Common Stock of the Company into which this Security could have been converted
immediately prior to such consolidation, merger, conveyance, transfer, sale or
lease. No adjustment in the Conversion Rate will be made until such adjustment
would require an increase or decrease of at least one percent of such price,
provided that any

                                      A-8
<PAGE>

adjustment that would otherwise be made will be carried forward and taken into
account in the computation of any subsequent adjustment.

Subordination
-------------

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

Events of Default
-----------------

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

Defeasance
----------

     The Indenture contains provisions for defeasance at any time of (a) the
entire indebtedness of the Company on this Security and (b) its obligation to
repurchase Securities upon the occurrence of a Change of Control and related
Defaults and Events of Default, upon compliance by the Company with certain
conditions set forth therein, which provisions apply to this Security.

Modification and Amendment
--------------------------

     The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders under the Indenture at any time by the
Company and the Trustee with the consent of the Holders of a majority in
aggregate principal amount of the Securities at the time Outstanding. The
Indenture also contains provisions permitting the Holders of specified
percentages in aggregate principal amount of the Securities at the time
Outstanding, on behalf of the Holders of all the Securities, to waive compliance
by the Company with certain provisions of the Indenture and certain past
defaults under the Indenture and their consequences. Without the consent of any
Holder of Securities, the Company and the Trustee may amend or modify the
Indenture for certain purposes specified therein. Any such consent or waiver by
or on behalf of the Holder of this Security shall be conclusive and binding upon
such Holder and upon all future Holders of this Security and of any Security
issued upon the registration of transfer hereof or in exchange herefor or in
lieu hereof whether or not notation of such consent or waiver is made upon this
Security.

Miscellaneous
-------------

     No reference herein to the Indenture and no provision of this Security or
of the Indenture shall alter or impair the obligation of the Company, which is
absolute and

                                      A-9
<PAGE>

unconditional, to pay the principal of (and premium, if any) and interest on
this Security at the times, place and rate, and in the coin or currency, herein
prescribed.

     As provided in the Indenture and subject to certain limitations therein set
forth, the transfer of this Security is registerable on the Security Register of
the Company, upon surrender of this Security for registration of transfer at the
office or agency of the Company maintained for such purpose in The City of New
York, duly endorsed by, or accompanied by a written instrument of transfer in
form satisfactory to the Company and the Security Registrar duly executed by,
the Holder hereof or his attorney duly authorized in writing, and thereupon one
or more new Securities, of authorized denominations and for the same aggregate
principal amount, will be issued to the designated transferee or transferees.
The Securities are issuable only in registered form without coupons in
denominations of $1,000 principal amount and any integral multiple thereof. As
provided in the Indenture and subject to certain limitations therein set forth,
the Securities are exchangeable for a like aggregate principal amount of
Securities of a different authorized denomination, as requested by the Holder
surrendering the same.

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

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

     THIS SECURITY SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAW
OF THE STATE OF NEW YORK BUT WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF
CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER
JURISDICTION WOULD BE REQUIRED THEREBY.

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

                                     A-10
<PAGE>

                Form of Trustee's Certificate of Authentication
                -----------------------------------------------

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


                    TRUSTEE'S CERTIFICATE OF AUTHENTICATION


     Dated:  _____________


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

                              THE BANK OF NEW YORK, as Trustee

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

                                     A-11
<PAGE>

                               CONVERSION NOTICE

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


Dated:__________


                                 Signature(s)

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


Name


Address


Social Security or other Identification
Number, if any


Signature Guaranteed

                                     A-12
<PAGE>

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

1.   Principal amount to be converted:

          $

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

          Amount $


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

                                     A-13
<PAGE>

                                Assignment Form
                                ---------------

     If you, the Holder, want to assign this Security, fill in the form below
and have your signature guaranteed:

I or we assign and transfer this Security to___________________________________

(Insert assignee's social security or tax ID number)

                                                       ___________________

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

____________________________________________________________________

                                                       ___________________

____________________________________________________________________


and irrevocably appoint_________________________________

of   _______________________________________

____________________________________________

agent to transfer this Security on the books of the Company.  The agent may
substitute another to act for such agent.


Dated:  _________  Your signature:  _________________________________________
                                    (Sign exactly as your name appears on the
                                    other side of this Security)

                   By:

                                    _________________________________
                                    NOTICE: To be executed by an executive
                                    officer

Signature Guarantee:  _________________________

                                     A-14
<PAGE>

                      Option of Holder to Elect Purchase

     If you wish to have this Security purchased by the Company pursuant to
Section 9.1 of the Second Supplemental Indenture, check the box:  [_]

     If you wish to have a portion of this Security purchased by the Company
pursuant to Section 9.1 of the Second Supplemental Indenture, state the amount:
$______________.

     In the event that the Purchase Price shall be paid in shares of Common
Stock of the Company, provide the name in which the certificate(s) for shares of
Common Stock of the Company are to be issued, together with the address of such
person:

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

(Print or type name, address and zip code)


Name


Address


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

                                     A-15
<PAGE>

                     [TO BE ATTACHED TO GLOBAL SECURITIES]

             SCHEDULE OF INCREASES OR DECREASES IN GLOBAL SECURITY

          The initial principal amount of this Global Security is $[        ].
The following increases or decreases in this Global Security have been made:

<TABLE>
<CAPTION>
Date of       Amount of decrease in       Amount of increase in     Principal amount of this   Signature of authorized
Transfer      Principal  Amount of this   Principal Amount of this  Global Security following  signatory of Trustee or
              Global Security             Global Security           such decrease or increase  Security Registrar
<S>           <C>                         <C>                       <C>                        <C>
 </TABLE>

                                     A-16