Exhibit 4.17


                          THIRD SUPPLEMENTAL INDENTURE

      THIS THIRD SUPPLEMENTAL INDENTURE (this "SUPPLEMENT"), dated as of [  ],
2002, among AT&T Corp., a corporation duly organized and validly existing under
the laws of the State of New York (the "COMPANY"), AT&T Broadband Corp., a
corporation duly organized and validly existing under the laws of Delaware
("BROADBAND") and The Bank of New York, a corporation duly organized and validly
existing under the laws of New York, as Trustee (the "TRUSTEE") under the
Indenture, dated as of September 7, 1990, between the Company and the Trustee,
the First Supplemental Indenture, dated as of October 30, 1992, between the
Company and the Trustee and the Second Supplemental Indenture, dated as of [ ],
2002, between the Company and the Trustee (as so modified, the "INDENTURE").
Capitalized terms used in this Supplement and not otherwise defined herein shall
have the meanings set forth in the Indenture.

                                    RECITALS

      WHEREAS, the Company has entered into an Agreement and Plan of Merger by
and among the Company, Broadband, Comcast Corporation, AT&T Broadband
Acquisition Corp., Comcast Acquisition Corp. and AT&T Comcast Corporation dated
as of December 19, 2001, as it may be amended, supplemented or otherwise
modified from time to time, whether prior to or after the date hereof (the
"MERGER AGREEMENT");

      WHEREAS, in connection with the Merger Agreement, the Company is offering
to exchange certain of its Securities for a like principal amount of Broadband
Exchange Notes (as defined below),

      WHEREAS, in accordance with Sections 2.02, 9.01, 10.04 and 10.05 of the
Indenture, the Company may provide for the issuance of and establish the form
and terms and conditions of any series of Securities to be issued under the
Indenture by an indenture supplemental thereto without the consent of any holder
of Securities thereunder;

      WHEREAS, the Company and Broadband desire to provide for the issuance of
and establish the form and certain terms and conditions of (1) the 7.00%
Broadband Exchange Notes Due May 15, 2022, (2) the 7.50% Broadband Exchange
Notes Due January 1, 2006, (3) the 7.75% Broadband Exchange Notes Due March 1,
2007, (4) the 6.00% Broadband Exchange Notes Due March 15, 2009, (5) the 8.125%
Broadband Exchange Notes Due January 15, 2022, (6) the 8.125% Broadband Exchange
Notes Due July 15, 2024, (7) the 8.35% Broadband Exchange Notes Due January 15,
2025 and (8) the 8.625% Broadband Exchange Notes Due December 1, 2031 (each a
separate Series under the Indenture and collectively, the "BROADBAND EXCHANGE
NOTES") in accordance with Sections 2.02 and 9.01 of the Indenture and has
requested the Trustee to join with it in the execution and delivery of this
Supplement; all requirements necessary to make this Supplement a valid
instrument, in accordance with its terms, have been met; and the execution and
delivery hereof have been in all respects duly authorized;

      WHEREAS, the Company and Broadband desire to provide for the mandatory
exchange at the Effective Time (as defined in the Merger Agreement) of the
Broadband Exchange Notes of each Series for New Broadband Notes issued under the
Broadband Indenture (as defined below);

      NOW, THEREFORE, for good and valuable consideration the sufficiency of
which is hereby recognized, and intending to be legally bound, the parties to
this Supplement hereby agree as follows:

                                    ARTICLE 1

  ESTABLISHMENT OF CERTAIN TERMS AND THE FORMS OF THE BROADBAND EXCHANGE NOTES

     Section 1.01. Broadband as Co-Issuer of Broadband Exchange Notes, Issuer of
New Broadband Notes. Broadband, by its execution of this Supplement, agrees (a)
to jointly and severally issue the Broadband Exchange Notes with the Company and
to be bound by the terms of the Indenture applicable to the Broadband Exchange
Notes to the same extent as the Company as if Broadband were a party thereto
directly, subject to the terms hereof and (b) to issue the New Broadband Notes
pursuant to the terms of the Broadband Indenture (as defined below) in exchange
for the Broadband Exchange Notes in connection with the Mandatory Exchange
described in Section 1.02.

     Section 1.02. Mandatory Exchange. (a) As of the Effective Time (as defined
above), each $1,000 principal amount of Broadband Exchange Notes of a Series
shall be mandatorily exchanged (the "MANDATORY EXCHANGE") at the applicable
exchange ratio set forth below for New Broadband Notes for such Series as
follows:



                                   EXCHANGE
    BROADBAND EXCHANGE NOTES        RATIO           NEW BROADBAND NOTES
    ------------------------        -----           -------------------
                                        

7.00% Broadband Exchange Notes
  Due May 15, 2022..............              New Broadband Notes Due [  ], 2013

7.50% Broadband Exchange Notes
  Due January 1, 2006...........              New Broadband Notes Due [  ], 2013

7.75% Broadband Exchange Notes
  Due March 1, 2007.............              New Broadband Notes Due [  ], 2013

6.00% Broadband Exchange Notes
  Due March 15, 2009............              New Broadband Notes Due [  ], 2013

8.125% Broadband Exchange Notes
  Due January 15, 2022..........              New Broadband Notes Due [  ], 2022




                                       2


                                        
8.125% Broadband Exchange Notes
  Due July 15, 2024.............              New Broadband Notes Due [  ], 2022

8.35% Broadband Exchange Notes
  Due January 15, 2025..........              New Broadband Notes Due [  ], 2022

8.625% Broadband Exchange Notes
  Due December 1, 2031..........              New Broadband Notes Due [  ], 2022


      (b) New Broadband Notes shall only be issued in denominations of $1,000
and multiples of $1,000. If the Mandatory Exchange would result in a Holder
being entitled to receive a fractional interest in the relevant series of New
Broadband Notes, the principal amount such Holder shall receive shall be rounded
down to the nearest $1,000 multiple and such Holder shall receive cash in lieu
of a fractional New Broadband Note for the balance.

      (c) Interest accrued and unpaid on any Series of Broadband Exchange Notes
shall be paid on the date of the Mandatory Exchange.

      (d) Each Holder of Broadband Exchange Notes is deemed by virtue of having
acquired such Securities, to have expressly and irrevocably consented to the
Mandatory Exchange.

      Section 1.03. Broadband Indenture. "BROADBAND INDENTURE" shall refer to
the indenture dated as of the date hereof among Broadband, as issuer, the Cable
Guarantors party thereto and The Bank of New York, as trustee, pursuant to which
the New Broadband Notes will be issued in exchange for the Broadband Exchange
Notes.

      Section 1.04. Release of Company and Broadband Upon Mandatory Exchange.
Upon completion of the Mandatory Exchange with respect to any of the Broadband
Exchange Notes and payment in full of all interest payable pursuant to Section
1.02(c) hereof, the Company and Broadband shall be fully and completely
discharged and released from their obligations under the Indenture and such
Broadband Exchange Notes with respect to such Broadband Exchange Notes,
including their obligations for the payment of principal and interest on the
Broadband Exchange Notes.

      Section 1.05. Release of Broadband Upon Termination of Merger Agreement.
If the Merger Agreement is terminated and the Mergers (as defined therein) are
abandoned at any time prior to the Effective Time, (a) Broadband shall be fully
and completely released from its obligations under the Indenture and the
Broadband Exchange Notes with respect to the Broadband Exchange Notes, including
its obligations for the payment of principal and interest on the Broadband
Exchange Notes, and (b) the Broadband Exchange Notes shall cease to be
exchangeable for the New Broadband Notes.

      Section 1.06. Discharge Upon Mandatory Exchange; Discharge Upon
Termination of Merger Agreement. (a) If at any time in connection with the
Mandatory Exchange, the Company shall have either (1) delivered to the Trustee
cancelled or for cancellation all Broadband Exchange Notes of a Series
theretofore authenticated (other than Broadband Exchange Notes which shall have
been mutilated, destroyed, lost or stolen and which shall have been replaced as
provided in Section 2.09 of the Indenture), or (2) delivered to the Trustee an
Officers' Certificate stating that the Mandatory Exchange has been completed
with respect to such Series and all outstanding Broadband Exchange Notes of such
Series have been replaced by New Broadband Notes, then the Indenture shall cease
to be of further effect with


                                       3

respect to the Broadband Exchange Notes replaced by the New Broadband Notes and
the Trustee on demand of, and at the cost and expense of the Company and
Broadband, shall execute proper instruments acknowledging satisfaction of, and
release of the Company from their/its obligations under, and discharging the
Indenture and the Broadband Exchange Notes.

      (b) If at any time the Company shall have delivered to the Trustee an
Officers' Certificate stating that the Merger Agreement has been terminated and
the Mergers (as defined therein) have been abandoned prior to the Effective
Time, then the Indenture and the Broadband Exchange Notes shall cease to be of
further effect with respect to Broadband and the Trustee on demand of, and at
the cost and expense of the Company and Broadband, shall execute proper
instruments acknowledging satisfaction of, and release of Broadband from its
obligations under, and discharging the Indenture and the Broadband Exchange
Notes with respect to Broadband.

      Section 1.07. Effect of Covered Transactions. The transactions
contemplated by the Separation and Distribution Agreement, dated as of December
19, 2001, as it may be amended, supplemented or otherwise modified from time to
time, whether prior to or after the date hereof (the "SEPARATION AND
DISTRIBUTION AGREEMENT"), the Merger Agreement, including without limitation the
Separation and Distribution (as such terms are defined in the Separation and
Distribution Agreement) as they may be amended, supplemented or otherwise
modified from time to time, whether prior to or after the date hereof
(collectively, the "COVERED TRANSACTIONS"), individually or together, (a) will
not result in a consolidation, merger, sale, conveyance or other transfer of
property of the Company (including stock of subsidiaries) as an entirety or
substantially as an entirety for purposes of Section 5.01 of the Indenture or
any other provision of the Indenture or any Broadband Exchange Note, and (b)
will not violate Sections 5.01, 5.02 or 5.03 of the Indenture or any other
provision of the Indenture or any Broadband Exchange Note, regardless of whether
any person assumes any of the Indebtedness outstanding under this Indenture or
any other obligation under this Indenture or any Broadband Exchange Note.

      Section 1.08. Form and Other Terms of The Broadband Exchange Notes.
Article 3 The Broadband Exchange Notes will be substantially in the form
attached as Exhibit A. The terms and provisions contained in the form of the
Broadband Exchange Notes annexed as Exhibit A constitute are hereby expressly
made, a part of the Indenture.

      (a) The remaining terms of each Series of Broadband Exchange Notes shall
be established pursuant to Section 2.02 of the Indenture at or prior to the
issuance of such Series of Broadband Exchange Notes.

                                   ARTICLE 2

                                  MISCELLANEOUS

      Section 2.01. Effectiveness of Provisions. Upon the execution of this
Supplement by the Company, Broadband and the Trustee, the Indenture shall be
modified in accordance herewith, and this Supplement shall form a part of the
Indenture for all purposes, and every holder of Broadband Exchange Notes
hereafter authenticated and delivered under the Indenture shall be bound hereby.

      Section 2.02. Indenture Remains in Full Force and Effect. Except as
supplemented hereby, all provisions in the Indenture shall remain in full force
and effect.

      Section 2.03. Execution of Supplement. This Supplement is executed and
shall be construed as an indenture supplemental to the Indenture and, as
provided in the Indenture, this Supplement forms a part thereof.

      Section 2.04. Conflict with Trust Indenture Act. If and to the extent that
any provision of this Supplement limits, qualifies or conflicts with the duties
imposed by any of Sections 310 to 317, inclusive, of the Trust Indenture Act,
such imposed duties shall control.

      Section 2.05. Separability Clause. In case any one or more of the
provisions contained in this Supplement, the Indenture or in the Broadband
Exchange Notes of any series shall for any reason be held to be invalid, illegal
or unenforceable in any respect, such invalidity, illegality or unenforceability
shall not affect any other provisions of this Supplement, the Indenture or of
such Broadband Exchange Notes, but this Supplement, the Indenture and such
Broadband Exchange Notes shall be construed as if such invalid or illegal or
unenforceable provision had never been contained herein or therein.

      Section 2.06. Benefits of the Supplement. Nothing in this Supplement or in
the Indenture, express or implied, shall give to any person, other than the
parties hereto and their successors hereunder and the holders of Broadband
Exchange Notes (to the extent specified


                                       4

herein or therein), any benefit or any legal or equitable right, remedy or claim
under this Supplement.

      Section 1.07. Successors and Assigns. All covenants and agreements in this
Supplement by the Company or Broadband shall bind their respective successors
and assigns, whether so expressed or not.


      Section 1.08. Governing Law. This Supplement shall be governed by, and
construed in accordance with, the laws of the State of New York.


      Section 1.09. Counterparts. This Supplement may be executed in any number
of counterparts, each of which is an original; but all such counterparts shall
together constitute but one and the same instrument.

      Section 1.10. Miscellaneous. Except as expressly supplemented by this
Supplement, the Indenture shall remain unchanged and in full force and effect.







                                       5

            IN WITNESS WHEREOF, the parties hereto have caused this Supplement
to be duly executed by their respective officers as of the day and year first
written above.

                                      AT&T CORP.
                                      By:
                                         -------------------------------------
                                         Name:
                                         Title:

[Corporate Seal]

Attest:

By:
   ---------------------------

                                      AT&T BROADBAND CORP.
                                      By:
                                         -------------------------------------
                                         Name:
                                         Title:

[Corporate Seal]

Attest:

By:
   ---------------------------

                                      THE BANK OF NEW YORK, as Trustee


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

[Corporate Seal]

Attest:

By:
   ---------------------------



                                       6

                                                                       EXHIBIT A

                        FORM OF BROADBAND EXCHANGE NOTES





                                       7

            [FORM OF 7.00% BROADBAND EXCHANGE NOTES DUE MAY 15, 2005]

                 PERMANENT GLOBAL REGISTERED FIXED RATE SECURITY

      THIS NOTE IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE THEREOF. UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES
IN CERTIFICATED FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE
DEPOSITARY TRUST COMPANY, A NEW YORK CORPORATION ("DTC") TO A NOMINEE OF DTC OR
BY DTC OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC TO AT&T CORP. AND AT&T BROADBAND CORP. OR THEIR AGENT FOR
REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY NOTE ISSUED IS REGISTERED
IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS 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.

                                   AT&T CORP.

                              AT&T BROADBAND CORP.

                 7.00% Broadband Exchange Notes Due May 15, 2005

REGISTERED                                        CUSIP NO.
NO:                                                        ---------
    --------

      AT&T Corp., a New York corporation ("AT&T") and AT&T Broadband Corp., a
Delaware corporation ("BROADBAND," and with AT&T, each an "ISSUER" and
collectively, the "ISSUERS"), for value received, hereby jointly and severally
promise to pay to CEDE & CO. or registered assigns the principal sum of [    ]
on May 15, 2005, and to pay interest semiannually on May 15 and November 15,
commencing [     ], on said principal sum at the rate per annum specified in the
title of these Notes, from [     ] until the principal thereof is paid or made
available for payment.

      For purposes of this Note, "Company" within the meaning of the Indenture
referred to herein shall mean each Issuer.

      Reference is hereby made to the further provisions of this global security
(the "GLOBAL SECURITY") set forth on the reverse hereof, which further
provisions shall for all purposes have the same effect as if set forth in this
place.



                                       8

      This Global Security shall not be valid or become obligatory for any
purpose until the certificate of authentication hereon shall have been executed
by the Trustee under the Indenture referred to herein.

      IN WITNESS WHEREOF, each Issuer has caused this Global Security to be duly
executed under its corporate seal.

Dated: [           ], 2002

                                   AT&T Corp.


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

                                   Attest:


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



                                   AT&T Broadband Corp.


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

                                   Attest:


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



                                       9

TRUSTEE'S CERTIFICATE OF
AUTHENTICATION

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

THE BANK OF NEW YORK,
  As Trustee

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









                                       10

                                REVERSE OF NOTES

      The Issuers, jointly and severally, agree to pay the principal of,
premium, if any, and interest on, this Global Security in immediately available
funds at the office or agency of the Trustee maintained for that purpose in the
Borough of Manhattan, The City of New York, State of New York, in such coin or
currency of the United States of America as at the time of payment shall be
legal tender for payment of public and private debts; provided, however, that at
the option of the Issuers payment of interest on any Notes issued in definitive
form other than interest due at the Maturity Date shown above may be made by
check mailed to the address of the person entitled thereto as such address shall
appear in the Note register. Interest will be paid to persons in whose names the
Notes are registered at the close of business on the May 1 or November 1, as the
case may be, prior to any interest payment date. Except as otherwise set forth
in the Indenture, Notes in definitive form will not be issued.

     This Note is one of a duly authorized issue of securities of the Issuers,
issued and to be issued under and pursuant to an indenture, dated as of
September 7, 1990, between AT&T and The Bank of New York, as Trustee under
Indenture (herein referred to as the "TRUSTEE"), as amended by the First
Supplemental Indenture, dated as of October 30, 1992, between AT&T and the
Trustee, the Second Supplemental Indenture, dated as of [ ], 2002, between AT&T
and the Trustee, and the Third Supplemental Indenture, dated as of [ ], 2002,
among the Issuers and the Trustee (herein referred to as the "INDENTURE"), duly
executed and delivered by the Issuers to the Trustee, to which Indenture and all
indentures supplemental thereto reference is hereby made for description of the
rights, limitations of rights, obligations, duties and immunities thereunder of
the Trustee, the Issuers and the Holder (the words "HOLDERS" or "HOLDER" meaning
the registered holders or registered holder) of these Notes. To the extent the
terms of the Indenture and this Note are inconsistent, the terms of the
Indenture shall govern.

      In case an Event of Default with respect to the Notes, as defined in the
Indenture, shall have occurred and be continuing, the principal hereof may be
declared, and upon such declaration shall become due and payable in the manner,
with the effect and subject to the conditions provided in the Indenture.

      The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Issuers and the rights of the Holders of the Notes to be affected under the
Indenture at any time by the Issuers and the Trustee with the consent of the
Holders of a majority in principal amount of the outstanding Notes. The
Indenture also contains provisions permitting the Holders of not less than a
majority in principal amount of the outstanding Notes, on behalf of the Holders
of all Notes, to waive compliance by the Issuers with certain provisions of the
Indenture. The Indenture also provides that the Holders of not less than a
majority in principal amount of the outstanding Notes may waive certain past
defaults and their consequences on behalf of the Holders of all Notes. Any such
consent or waiver by the Holder of any Note shall be conclusive and binding upon
such Holder and upon all future Holders of such Note and of any Note issued upon
registration of transfer hereof or in exchange herefor or in lieu hereof whether
or not notation of such consent or waiver is made upon such Note.

      The Indenture also provides that the Covered Transactions (as defined in
the Indenture), individually or together, (a) will not result in a
consolidation, merger, sale, conveyance or other transfer of property of




                                       11

any Issuer (including stock of subsidiaries) as an entirety or substantially as
an entirety for purposes of Section 5.01 of the Indenture or any other provision
of the Indenture or these Notes, and (b) will not violate Sections 5.01, 5.02 or
5.03 of the Indenture or any other provision of the Indenture or these Notes,
regardless of whether any person assumes any of the indebtedness outstanding
under the Indenture or any other obligation under the Indenture or these Notes.

      The Indenture contains provisions setting forth certain conditions to the
institution of proceedings by Holders of Notes with respect to the Indenture or
for any remedy under the Indenture.

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

      The Notes are issuable as registered Notes without coupons in
denominations of U.S. $1,000 or any amount in excess thereof which is a multiple
of U.S. $1,000 at the office or agency of the Trustee referred to above and in
the manner and subject to the limitations provided in the Indenture. Notes may
be exchanged without service charge for like aggregate principal amount of
Notes.

      At the Effective Time (as defined in the Merger Agreement), each $1,000
principal amount of Notes shall be mandatorily exchanged (the "MANDATORY
EXCHANGE") for $[     ] principal amount of [     ]% Notes Due [     ], 2013
("NEW BROADBAND NOTES").

      New Broadband Notes shall only be issued in denominations of $1,000 and
multiples of $1,000. If the Mandatory Exchange would result in a Holder being
entitled to receive a fractional interest in the New Broadband Notes, the
principal amount such Holder shall receive shall be rounded down to the nearest
$1,000 multiple and such Holder shall receive cash in lieu of a fractional New
Broadband Note for the balance.

      Interest accrued and unpaid on the Notes shall be paid on the date of the
Mandatory Exchange.

      Each Holder of the Notes is deemed, by virtue of having acquired such
Notes, to have expressly and irrevocably consented to the Mandatory Exchange.

      "MERGER AGREEMENT" means the Agreement and Plan of Merger by and among the
Issuers, Comcast Corporation, AT&T Broadband Acquisition Corp., Comcast
Acquisition Corp. and AT&T Comcast Corporation dated as of December 19, 2001, as
it may be amended, supplemented or otherwise modified from time to time, whether
prior to or after the date hereof.

      "BROADBAND INDENTURE" shall refer to the indenture dated as of [     ],
2002, among Broadband, as issuer, the Cable Guarantors party thereto and The
Bank of New York, as trustee, pursuant to which the New Broadband Notes will be
issued in exchange for the Notes.

      Upon completion of the Mandatory Exchange with respect to Notes and
payment in full of all interest payable pursuant to the eleventh paragraph of
this reverse of this Note, the Issuers


                                       12

shall be fully and completely discharged and released from their obligations
under the Indenture and the Notes with respect to the Notes, including their
obligations for the payment of principal and interest on the Notes.

      If the Merger Agreement is terminated and the Mergers (as defined therein)
are abandoned at any time prior to the Effective Time, (a) Broadband shall be
fully and completely released from its obligations under the Indenture and the
Notes with respect to the Notes, including its obligations for the payment of
principal and interest on the Notes, and (b) the Notes shall cease to be
exchangeable for the New Broadband Notes.

      The Notes may not be redeemed by the Issuers prior to maturity.

      Upon due presentment for registration of transfer of this Note at the
above-mentioned office or agency of the Trustee, a new Global Security or Notes
of authorized denominations, for a like aggregate principal amount will be
issued to the transferee as provided in the Indenture. No service charge shall
be made for any such transfer, but the Issuers may require payment of a sum
sufficient to cover any tax or other governmental charge that may be imposed in
relation thereto.

      The Issuers, the Trustee, and any agent of the either Issuer or the
Trustee may deem and treat the Holder hereof as the absolute owner hereof
(whether or not this Global Security shall be overdue and notwithstanding any
notation of ownership or other writing hereon) for the purpose of receiving
payment of or on account of the principal hereof and subject to the provisions
above, of premium or interest thereon, and for all other purposes and neither
the Issuers nor the Trustee nor any such agent shall be affected by any notice
to the contrary.

      No recourse shall be had for the payment of the principal of, premium, if
any, or the interest on, this Global Security or for any claim based hereon, or
otherwise in respect hereof, or based on or in respect of the Indenture or any
indenture supplemental thereto, against any incorporator, shareholder, officer
or director as such, past, present or future, of the Issuers or of any successor
corporation, either directly or through the Issuers or of any successor
corporation whether by virtue of any constitution, statute or rule of law or by
the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

      This Global Security shall be deemed to be a contract made under the laws
of the State of New York and for all purposes shall be governed by and construed
in accordance with the laws of said State.

      Unless otherwise defined in this Global Security, all terms used in this
Global Security which are defined in the Indenture shall have the meanings
assigned to them in the Indenture.


                                       13

                                  ABBREVIATIONS

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

      TEN COM     - as tenants in common

      TEN ENT     - as tenants by the entireties

      JT TEN      - as joint tenants with right of survivorship and not as
                    tenants in common

      UNIF GIFT MIN ACT -                 (Cust)           (Minor)
                          ----------------      -----------

      Under Uniform Gifts to Minor Act                 (State)
                                       ----------------

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

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

[PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE]

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

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

[PLEASE PRINT OR TYPE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE]

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

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

the within Notes and all rights thereunder, hereby irrevocably constituting and
appointing such person attorney to transfer such Note on the books of the
Issuers, with full power of substitution in the premises.

Date:


NOTICE:     The signature of this assignment must correspond with the name as
            written upon the face of the within Notes in every particular
            without alteration or enlargement or any change whatsoever.



                                       14

            [FORM OF 7.50% BROADBAND EXCHANGE NOTES DUE JUNE 1, 2006]

                 PERMANENT GLOBAL REGISTERED FIXED RATE SECURITY

      THIS NOTE IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE THEREOF. UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES
IN CERTIFICATED FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC") TO A NOMINEE OF DTC OR
BY DTC OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC TO AT&T CORP. AND AT&T BROADBAND CORP. OR ITS AGENTS FOR
REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY NOTE ISSUED IS REGISTERED
IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS 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.

                                   AT&T CORP.

                              AT&T BROADBAND CORP.

                 7.50% Broadband Exchange Notes Due June 1, 2006

REGISTERED [       ]                         CUSIP No. [        ]

      AT&T Corp., a New York corporation ("AT&T") and AT&T Broadband Corp., a
Delaware corporation ("BROADBAND," and with AT&T, each an "ISSUER" and
collectively, the "ISSUERS"), for value received, hereby jointly and severally
promise to pay to CEDE & CO. or registered assigns the principal sum of [     ]
on June 1, 2006, and to pay interest semiannually on June 1 and December 1,
commencing [     ], on said principal sum at the rate per annum specified in the
title of these Notes, from [     ] until the principal thereof is paid or made
available for payment.

      For purposes of this Note, "Company" within the meaning of the Indenture
referred to herein shall mean each Issuer.

      Reference is hereby made to the further provisions of this global security
(the "GLOBAL SECURITY") set forth on the reverse hereof, which further
provisions shall for all purposes have the same effect as if set forth in this
place.

      This Global Security shall not be valid or become obligatory for any
purpose until the certificate of authentication hereon shall have been executed
by the Trustee under the Indenture referred to herein.



                                       15

      IN WITNESS WHEREOF, each Issuer has caused this Global Security to be duly
executed under its corporate seal.

Dated:  [         ], 2002

                                   AT&T Corp.


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

                                   Attest:


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


                                   AT&T Broadband Corp.


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

                                   Attest:


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

TRUSTEE'S CERTIFICATE OF
AUTHENTICATION

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

THE BANK OF NEW YORK,
  As Trustee

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


                                       16

                                REVERSE OF NOTES

      The Issuers, jointly and severally, agree to pay the principal of,
premium, if any, and interest on, this Global Security in immediately available
funds at the office or agency of the Trustee maintained for that purpose in the
Borough of Manhattan, The City of New York, State of New York, in such coin or
currency of the United States of America as at the time of payment shall be
legal tender for payment of public and private debts; provided, however, that at
the option of the Issuers payment of interest on any Notes issued in definitive
form other than interest due at the Maturity Date shown above may be made by
check mailed to the address of the person entitled thereto as such address shall
appear in the Note register. Interest will be paid to persons in whose names the
Notes are registered at the close of business on the May 15 or November 15, as
the case may be, prior to any interest payment date. Except as otherwise set
forth in the Indenture, Notes in definitive form will not be issued.

      This Note is one of a duly authorized issue of securities of the Issuers,
issued and to be issued under and pursuant to an indenture, dated as of
September 7, 1990, between AT&T and The Bank of New York, as Trustee under
Indenture (herein referred to as the "TRUSTEE"), as amended by the First
Supplemental Indenture, dated as of October 30, 1992, between AT&T and the
Trustee, the Second Supplemental Indenture, dated as of [      ], 2002, between
AT&T and the Trustee, and the Third Supplemental Indenture, dated as of [     ],
2002, among the Issuers and the Trustee (herein referred to as the "INDENTURE"),
duly executed and delivered by the Issuers to the Trustee, to which Indenture
and all indentures supplemental thereto reference is hereby made for description
of the rights, limitations of rights, obligations, duties and immunities
thereunder of the Trustee, the Issuers and the Holder (the words "HOLDERS" or
"HOLDER" meaning the registered holders or registered holder) of these Notes. To
the extent the terms of the Indenture and this Note are inconsistent, the terms
of the Indenture shall govern.

      In case an Event of Default with respect to the Notes, as defined in the
Indenture, shall have occurred and be continuing, the principal hereof may be
declared, and upon such declaration shall become due and payable in the manner,
with the effect and subject to the conditions provided in the Indenture.

      The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Issuers and the rights of the Holders of the Notes to be affected under the
Indenture at any time by the Issuers and the Trustee with the consent of the
Holders of a majority in principal amount of the outstanding Notes. The
Indenture also contains provisions permitting the Holders of not less than a
majority in principal amount of the outstanding Notes, on behalf of the Holders
of all Notes, to waive compliance by the Issuers with certain provisions of the
Indenture. The Indenture also provides that the Holders of not less than a
majority in principal amount of the outstanding Notes may waive certain past
defaults and their consequences on behalf of the Holders of all Notes. Any such
consent or waiver by the Holder of any Note shall be conclusive and binding upon
such Holder and upon all future Holders of such Note and of any Note issued upon
registration of transfer hereof or in exchange herefor or in lieu hereof whether
or not notation of such consent or waiver is made upon such Note.

      The Indenture also provides that the Covered Transactions (as defined in
the Indenture), individually or together, (a) will not result in a
consolidation, merger, sale, conveyance or other transfer of property of


                                       17

any Issuer (including stock of subsidiaries) as an entirety or substantially as
an entirety for purposes of Section 5.01 of the Indenture or any other provision
of the Indenture or these Notes, and (b) will not violate Sections 5.01, 5.02 or
5.03 of the Indenture or any other provision of the Indenture or these Notes,
regardless of whether any person assumes any of the indebtedness outstanding
under the Indenture or any other obligation under the Indenture or these Notes.

      The Indenture contains provisions setting forth certain conditions to the
institution of proceedings by Holders of Notes with respect to the Indenture or
for any remedy under the Indenture.

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

      The Notes are issuable as registered Notes without coupons in
denominations of U.S. $1,000 or any amount in excess thereof which is a multiple
of U.S. $1,000 at the office or agency of the Trustee referred to above and in
the manner and subject to the limitations provided in the Indenture. Notes may
be exchanged without service charge for like aggregate principal amount of
Notes.

      At the Effective Time (as defined in the Merger Agreement), each $1,000
principal amount of Notes shall be mandatorily exchanged (the "MANDATORY
EXCHANGE") for $[     ] principal amount of [     ]% Notes Due [     ], 2013
("NEW BROADBAND NOTES").

      New Broadband Notes shall only be issued in denominations of $1,000 and
multiples of $1,000. If the Mandatory Exchange would result in a Holder being
entitled to receive a fractional interest in the New Broadband Notes, the
principal amount such Holder shall receive shall be rounded down to the nearest
$1,000 multiple and such Holder shall receive cash in lieu of a fractional New
Broadband Note for the balance.

      Interest accrued and unpaid on the Notes shall be paid on the date of the
Mandatory Exchange.

      Each Holder of the Notes is deemed, by virtue of having acquired such
Notes, to have expressly and irrevocably consented to the Mandatory Exchange.

      "MERGER AGREEMENT" means the Agreement and Plan of Merger by and among the
Issuers, Comcast Corporation, AT&T Broadband Acquisition Corp., Comcast
Acquisition Corp. and AT&T Comcast Corporation dated as of December 19, 2001, as
it may be amended, supplemented or otherwise modified from time to time, whether
prior to or after the date hereof.

      "BROADBAND INDENTURE" shall refer to the indenture dated as of [     ],
2002, among Broadband, as issuer, the Cable Guarantors party thereto and The
Bank of New York, as trustee, pursuant to which the New Broadband Notes will be
issued in exchange for the Notes.

      Upon completion of the Mandatory Exchange with respect to Notes and
payment in full of all interest payable pursuant to the eleventh paragraph of
this reverse of this Note, the Issuers


                                       18

shall be fully and completely discharged and released from their obligations
under the Indenture and the Notes with respect to the Notes, including their
obligations for the payment of principal and interest on the Notes.

      If the Merger Agreement is terminated and the Mergers (as defined therein)
are abandoned at any time prior to the Effective Time, (a) Broadband shall be
fully and completely released from its obligations under the Indenture and the
Notes with respect to the Notes, including its obligations for the payment of
principal and interest on the Notes, and (b) the Notes shall cease to be
exchangeable for the New Broadband Notes.

      The Notes may not be redeemed by the Issuers prior to maturity.

      Upon due presentment for registration of transfer of this Note at the
above-mentioned office or agency of the Trustee, a new Global Security or Notes
of authorized denominations, for a like aggregate principal amount will be
issued to the transferee as provided in the Indenture. No service charge shall
be made for any such transfer, but the Issuers may require payment of a sum
sufficient to cover any tax or other governmental charge that may be imposed in
relation thereto.

      The Issuers, the Trustee, and any agent of the either Issuer or the
Trustee may deem and treat the Holder hereof as the absolute owner hereof
(whether or not this Global Security shall be overdue and notwithstanding any
notation of ownership or other writing hereon) for the purpose of receiving
payment of or on account of the principal hereof and subject to the provisions
above, of premium or interest thereon, and for all other purposes and neither
the Issuers nor the Trustee nor any such agent shall be affected by any notice
to the contrary.

      No recourse shall be had for the payment of the principal of, or the
interest on, this Global Security or for any claim based hereon, or otherwise in
respect hereof, or based on or in respect of the Indenture or any indenture
supplemental thereto, against any incorporator, shareholder, officer or director
as such, past, present or future, of the Issuers or of any successor
corporation, either directly or through the Issuers or of any successor
corporation whether by virtue of any constitution, statute or rule of law or by
the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

      This Global Security shall be deemed to be a contract made under the laws
of the State of New York and for all purposes shall be governed by and construed
in accordance with the laws of said State.

      Unless otherwise defined in this Global Security, all terms used in this
Global Security which are defined in the Indenture shall have the meanings
assigned to them in the Indenture.



                                       19

                                  ABBREVIATIONS

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

      TEN COM     - as tenants in common

      TEN ENT     - as tenants by the entireties

      JT TEN      - as joint tenants with right of survivorship and not as
                    tenants in common

      UNIF GIFT MIN ACT -                 (Cust)           (Minor)
                          ----------------      -----------

      Under Uniform Gifts to Minor Act                 (State)
                                       ----------------

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

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

[PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE]

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

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

[PLEASE PRINT OR TYPE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE]

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

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

the within Notes and all rights thereunder, hereby irrevocably constituting and
appointing such person attorney to transfer such Note on the books of the
Issuers, with full power of substitution in the premises.

Date:


NOTICE:     The signature of this assignment must correspond with the name as
            written upon the face of the within Notes in every particular
            without alteration or enlargement or any change whatsoever.





                                       20

           [FORM OF 7.75% BROADBAND EXCHANGE NOTES DUE MARCH 1, 2007]

                 PERMANENT GLOBAL REGISTERED FIXED RATE SECURITY

      THIS NOTE IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE THEREOF. UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES
IN CERTIFICATED FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC") TO A NOMINEE OF DTC OR
BY DTC OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC TO AT&T CORP. AND AT&T BROADBAND CORP. OR ITS AGENTS FOR
REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY NOTE ISSUED IS REGISTERED
IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS 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.

                                   AT&T CORP.

                              AT&T BROADBAND CORP.

                7.75% Broadband Exchange Notes Due March 1, 2007

REGISTERED [        ]                        CUSIP No. [         ]

      AT&T Corp., a New York corporation ("AT&T") and AT&T Broadband Corp., a
Delaware corporation ("BROADBAND," and with AT&T, each an "ISSUER" and
collectively, the "ISSUERS"), for value received, hereby jointly and severally
promise to pay to CEDE & CO. or registered assigns the principal sum of [     ]
on March 1, 2007, and to pay interest semiannually on March 1 and September 1,
commencing [     ], on said principal sum at the rate per annum specified in the
title of these Notes, from [     ] until the principal thereof is paid or made
available for payment.

      For purposes of this Note, "Company" within the meaning of the Indenture
referred to herein shall mean each Issuer.

      Reference is hereby made to the further provisions of this global security
(the "GLOBAL SECURITY") set forth on the reverse hereof, which further
provisions shall for all purposes have the same effect as if set forth in this
place.

      This Global Security shall not be valid or become obligatory for any
purpose until the certificate of authentication hereon shall have been executed
by the Trustee under the Indenture referred to herein.


                                       21

      IN WITNESS WHEREOF, each Issuer has caused this Global Security to be duly
executed under its corporate seal.

Dated: [          ], 2002

                                   AT&T Corp.


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

                                   Attest:


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


                                   AT&T Broadband Corp.


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

                                   Attest:


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

TRUSTEE'S CERTIFICATE OF
AUTHENTICATION

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

THE BANK OF NEW YORK,
  As Trustee

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


                                       22

                                REVERSE OF NOTES

      The Issuers, jointly and severally, agree to pay the principal of,
premium, if any, and interest on, this Global Security in immediately available
funds at the office or agency of the Trustee maintained for that purpose in the
Borough of Manhattan, The City of New York, State of New York, in such coin or
currency of the United States of America as at the time of payment shall be
legal tender for payment of public and private debts; provided, however, that at
the option of the Issuers payment of interest on any Notes issued in definitive
form other than interest due at the Maturity Date shown above may be made by
check mailed to the address of the person entitled thereto as such address shall
appear in the Note register. Interest will be paid to persons in whose names the
Notes are registered at the close of business on the February 15 or August 15,
as the case may be, prior to any interest payment date. Except as otherwise set
forth in the Indenture, Notes in definitive form will not be issued.

      This Note is one of a duly authorized issue of securities of the Issuers,
issued and to be issued under and pursuant to an indenture, dated as of
September 7, 1990, between AT&T and The Bank of New York, as Trustee under
Indenture (herein referred to as the "TRUSTEE"), as amended by the First
Supplemental Indenture, dated as of October 30, 1992, between AT&T and the
Trustee, the Second Supplemental Indenture, dated as of [     ], 2002, between
AT&T and the Trustee, and the Third Supplemental Indenture, dated as of [     ],
2002, among the Issuers and the Trustee (herein referred to as the "INDENTURE"),
duly executed and delivered by the Issuers to the Trustee, to which Indenture
and all indentures supplemental thereto reference is hereby made for description
of the rights, limitations of rights, obligations, duties and immunities
thereunder of the Trustee, the Issuers and the Holder (the words "HOLDERS" or
"HOLDER" meaning the registered holders or registered holder) of these Notes.
To the extent the terms of the Indenture and this Note are inconsistent, the
terms of the Indenture shall govern.

      In case an Event of Default with respect to the Notes, as defined in the
Indenture, shall have occurred and be continuing, the principal hereof may be
declared, and upon such declaration shall become due and payable in the manner,
with the effect and subject to the conditions provided in the Indenture.

      The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Issuers and the rights of the Holders of the Notes to be affected under the
Indenture at any time by the Issuers and the Trustee with the consent of the
Holders of a majority in principal amount of the outstanding Notes. The
Indenture also contains provisions permitting the Holders of not less than a
majority in principal amount of the outstanding Notes, on behalf of the Holders
of all Notes, to waive compliance by the Issuers with certain provisions of the
Indenture. The Indenture also provides that the Holders of not less than a
majority in principal amount of the outstanding Notes may waive certain past
defaults and their consequences on behalf of the Holders of all Notes. Any such
consent or waiver by the Holder of any Note shall be conclusive and binding upon
such Holder and upon all future Holders of such Note and of any Note issued upon
registration of transfer hereof or in exchange herefor or in lieu hereof whether
or not notation of such consent or waiver is made upon such Note.

      The Indenture also provides that the Covered Transactions (as defined in
the Indenture), individually or together, (a) will not result in a
consolidation, merger, sale, conveyance or other transfer of property of


                                       23

any Issuer (including stock of subsidiaries) as an entirety or substantially as
an entirety for purposes of Section 5.01 of the Indenture or any other provision
of the Indenture or these Notes, and (b) will not violate Sections 5.01, 5.02 or
5.03 of the Indenture or any other provision of the Indenture or these Notes,
regardless of whether any person assumes any of the indebtedness outstanding
under the Indenture or any other obligation under the Indenture or these Notes.

      The Indenture contains provisions setting forth certain conditions to the
institution of proceedings by Holders of Notes with respect to the Indenture or
for any remedy under the Indenture.

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

      The Notes are issuable as registered Notes without coupons in
denominations of U.S. $1,000 or any amount in excess thereof which is a multiple
of U.S. $1,000 at the office or agency of the Trustee referred to above and in
the manner and subject to the limitations provided in the Indenture. Notes may
be exchanged without service charge for like aggregate principal amount of
Notes.

      At the Effective Time (as defined in the Merger Agreement), each $1,000
principal amount of Notes shall be mandatorily exchanged (the "MANDATORY
EXCHANGE") for $[     ] principal amount of [     ]% Notes Due [     ], 2013
("NEW BROADBAND NOTES").

      New Broadband Notes shall only be issued in denominations of $1,000 and
multiples of $1,000. If the Mandatory Exchange would result in a Holder being
entitled to receive a fractional interest in the New Broadband Notes, the
principal amount such Holder shall receive shall be rounded down to the nearest
$1,000 multiple and such Holder shall receive cash in lieu of a fractional New
Broadband Note for the balance.

      Interest accrued and unpaid on the Notes shall be paid on the date of the
Mandatory Exchange.

      Each Holder of the Notes is deemed, by virtue of having acquired such
Notes, to have expressly and irrevocably consented to the Mandatory Exchange.

      "MERGER AGREEMENT" means the Agreement and Plan of Merger by and among the
Issuers, Comcast Corporation, AT&T Broadband Acquisition Corp., Comcast
Acquisition Corp. and AT&T Comcast Corporation dated as of December 19, 2001, as
it may be amended, supplemented or otherwise modified from time to time, whether
prior to or after the date hereof.

      "BROADBAND INDENTURE" shall refer to the indenture dated as of [     ],
2002, among Broadband, as issuer, the Cable Guarantors party thereto and The
Bank of New York, as trustee, pursuant to which the New Broadband Notes will be
issued in exchange for the Notes.

      Upon completion of the Mandatory Exchange with respect to Notes and
payment in full of all interest payable pursuant to the eleventh paragraph of
this reverse of this Note, the Issuers


                                       24

shall be fully and completely discharged and released from their obligations
under the Indenture and the Notes with respect to the Notes, including their
obligations for the payment of principal and interest on the Notes.

      If the Merger Agreement is terminated and the Mergers (as defined therein)
are abandoned at any time prior to the Effective Time, (a) Broadband shall be
fully and completely released from its obligations under the Indenture and the
Notes with respect to the Notes, including its obligations for the payment of
principal and interest on the Notes, and (b) the Notes shall cease to be
exchangeable for the New Broadband Notes.

      The Notes may not be redeemed by the Issuers prior to maturity.

      Upon due presentment for registration of transfer of this Note at the
above-mentioned office or agency of the Trustee, a new Global Security or Notes
of authorized denominations, for a like aggregate principal amount will be
issued to the transferee as provided in the Indenture. No service charge shall
be made for any such transfer, but the Issuers may require payment of a sum
sufficient to cover any tax or other governmental charge that may be imposed in
relation thereto.

      The Issuers, the Trustee, and any agent of the either Issuer or the
Trustee may deem and treat the Holder hereof as the absolute owner hereof
(whether or not this Global Security shall be overdue and notwithstanding any
notation of ownership or other writing hereon) for the purpose of receiving
payment of or on account of the principal hereof and subject to the provisions
above, of premium or interest thereon, and for all other purposes and neither
the Issuers nor the Trustee nor any such agent shall be affected by any notice
to the contrary.

      No recourse shall be had for the payment of the principal of, premium, if
any, or the interest on, this Global Security or for any claim based hereon, or
otherwise in respect hereof, or based on or in respect of the Indenture or any
indenture supplemental thereto, against any incorporator, shareholder, officer
or director as such, past, present or future, of the Issuers or of any successor
corporation, either directly or through the Issuers or of any successor
corporation whether by virtue of any constitution, statute or rule of law or by
the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

      This Global Security shall be deemed to be a contract made under the laws
of the State of New York and for all purposes shall be governed by and construed
in accordance with the laws of said State.

      Unless otherwise defined in this Global Security, all terms used in this
Global Security which are defined in the Indenture shall have the meanings
assigned to them in the Indenture.


                                       25

                                  ABBREVIATIONS

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

      TEN COM     - as tenants in common

      TEN ENT     - as tenants by the entireties

      JT TEN      - as joint tenants with right of survivorship and not as
                    tenants in common

      UNIF GIFT MIN ACT -                 (Cust)           (Minor)
                          ----------------      -----------

      Under Uniform Gifts to Minor Act                 (State)
                                       ----------------

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

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

[PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE]

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

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

[PLEASE PRINT OR TYPE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE]

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

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

the within Notes and all rights thereunder, hereby irrevocably constituting and
appointing such person attorney to transfer such Note on the books of the
Issuers, with full power of substitution in the premises.

Date:


NOTICE:     The signature of this assignment must correspond with the name as
            written upon the face of the within Notes in every particular
            without alteration or enlargement or any change whatsoever.



                                       26


           [FORM OF 6.00% BROADBAND EXCHANGE NOTES DUE MARCH 15, 2009]

                 PERMANENT GLOBAL REGISTERED FIXED RATE SECURITY
      THIS NOTE IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE THEREOF. UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES
IN CERTIFICATED FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC") TO A NOMINEE OF DTC OR
BY DTC OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC TO AT&T CORP. AND AT&T BROADBAND CORP. OR ITS AGENTS FOR
REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY NOTE ISSUED IS REGISTERED
IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS 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.


                                   AT&T CORP.

                              AT&T BROADBAND CORP.

                6.00% Broadband Exchange Notes Due March 15, 2009

REGISTERED [                   ]                 CUSIP No. [                   ]

      AT&T Corp., a New York corporation ("AT&T") and AT&T Broadband Corp., a
Delaware corporation ("BROADBAND," and with AT&T, each an "ISSUER" and
collectively, the "ISSUERS"), for value received, hereby jointly and severally
promise to pay to CEDE & CO. or registered assigns the principal sum of [ ] on
March 15, 2009, and to pay interest semiannually on March 15 and September 15,
commencing [ ], on said principal sum at the rate per annum specified in the
title of these Notes, from [ ] until the principal thereof is paid or made
available for payment.

      For purposes of this Note, "Company" within the meaning of the Indenture
referred to herein shall mean each Issuer.

      Reference is hereby made to the further provisions of this global security
(the "GLOBAL SECURITY") set forth on the reverse hereof, which further
provisions shall for all purposes have the same effect as if set forth in this
place.

      This Global Security shall not be valid or become obligatory for any
purpose until the certificate of authentication hereon shall have been executed
by the Trustee under the Indenture referred to herein.


                                       27

      IN WITNESS WHEREOF, each Issuer has caused this Global Security to be duly
executed under its corporate seal.

Dated:  [                    ], 2002

                                   AT&T Corp.


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

                                   Attest:


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


                                   AT&T Broadband Corp.


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

                                   Attest:


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

TRUSTEE'S CERTIFICATE OF
AUTHENTICATION

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

THE BANK OF NEW YORK,
  As Trustee

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


                                       28

                                REVERSE OF NOTES


      The Issuers, jointly and severally, agree to pay the principal of,
premium, if any, and interest on, this Global Security in immediately available
funds at the office or agency of the Trustee maintained for that purpose in the
Borough of Manhattan, The City of New York, State of New York, in such coin or
currency of the United States of America as at the time of payment shall be
legal tender for payment of public and private debts; provided, however, that at
the option of the Issuers payment of interest on any Notes issued in definitive
form other than interest due at the Maturity Date shown above may be made by
check mailed to the address of the person entitled thereto as such address shall
appear in the Note register. Interest will be paid to persons in whose names the
Notes are registered at the close of business on the March 1 or September 1, as
the case may be, prior to any interest payment date. Except as otherwise set
forth in the Indenture, Notes in definitive form will not be issued.

      This Note is one of a duly authorized issue of securities of the Issuers,
issued and to be issued under and pursuant to an indenture, dated as of
September 7, 1990, between AT&T and The Bank of New York, as Trustee under
Indenture (herein referred to as the "TRUSTEE"), as amended by the First
Supplemental Indenture, dated as of October 30, 1992, between AT&T and the
Trustee, the Second Supplemental Indenture, dated as of [ ], 2002, between AT&T
and the Trustee, and the Third Supplemental Indenture, dated as of [ ], 2002,
among the Issuers and the Trustee (herein referred to as the "Indenture"), duly
executed and delivered by the Issuers to the Trustee, to which Indenture and all
indentures supplemental thereto reference is hereby made for description of the
rights, limitations of rights, obligations, duties and immunities thereunder of
the Trustee, the Issuers and the Holder (the words "HOLDERS" or "HOLDER" meaning
the registered holders or registered holder) of these Notes. To the extent the
terms of the Indenture and this Note are inconsistent, the terms of the
Indenture shall govern.

      In case an Event of Default with respect to the Notes, as defined in the
Indenture, shall have occurred and be continuing, the principal hereof may be
declared, and upon such declaration shall become due and payable in the manner,
with the effect and subject to the conditions provided in the Indenture.

      The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Issuers and the rights of the Holders of the Notes to be affected under the
Indenture at any time by the Issuers and the Trustee with the consent of the
Holders of a majority in principal amount of the outstanding Notes. The
Indenture also contains provisions permitting the Holders of not less than a
majority in principal amount of the outstanding Notes, on behalf of the Holders
of all Notes, to waive compliance by the Issuers with certain provisions of the
Indenture. The Indenture also provides that the Holders of not less than a
majority in principal amount of the outstanding Notes may waive certain past
defaults and their consequences on behalf of the Holders of all Notes. Any such
consent or waiver by the Holder of any Note shall be conclusive and binding upon
such Holder and upon all future Holders of such Note and of any Note issued upon
registration of transfer hereof or in exchange herefor or in lieu hereof whether
or not notation of such consent or waiver is made upon such Note.

     The Indenture also provides that the Covered Transactions (as defined in
the Indenture), individually or together, (a) will not result in a
consolidation, merger, sale, conveyance or other transfer of property of


                                       29

any Issuer (including stock of subsidiaries) as an entirety or substantially as
an entirety for purposes of Section 5.01 of the Indenture or any other provision
of the Indenture or these Notes, and (b) will not violate Sections 5.01, 5.02 or
5.03 of the Indenture or any other provision of the Indenture or these Notes,
regardless of whether any person assumes any of the indebtedness outstanding
under the Indenture or any other obligation under the Indenture or these Notes.

      The Indenture contains provisions setting forth certain conditions to the
institution of proceedings by Holders of Notes with respect to the Indenture or
for any remedy under the Indenture.

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

      The Notes are issuable as registered Notes without coupons in
denominations of U.S. $1,000 or any amount in excess thereof which is a multiple
of U.S. $1,000 at the office or agency of the Trustee referred to above and in
the manner and subject to the limitations provided in the Indenture. Notes may
be exchanged without service charge for like aggregate principal amount of
Notes.

      At the Effective Time (as defined in the Merger Agreement), each $1,000
principal amount of Notes shall be mandatorily exchanged (the "MANDATORY
EXCHANGE") for $[ ] principal amount of [ ]% Notes Due [ ], 2013 ("NEW BROADBAND
NOTES").

      New Broadband Notes shall only be issued in denominations of $1,000 and
multiples of $1,000. If the Mandatory Exchange would result in a Holder being
entitled to receive a fractional interest in the New Broadband Notes, the
principal amount such Holder shall receive shall be rounded down to the nearest
$1,000 multiple and such Holder shall receive cash in lieu of a fractional New
Broadband Note for the balance.

      Interest accrued and unpaid on the Notes shall be paid on the date of the
Mandatory Exchange.

      Each Holder of the Notes is deemed, by virtue of having acquired such
Notes, to have expressly and irrevocably consented to the Mandatory Exchange.

      "MERGER AGREEMENT" means the Agreement and Plan of Merger by and among the
Issuers, Comcast Corporation, AT&T Broadband Acquisition Corp., Comcast
Acquisition Corp. and AT&T Comcast Corporation dated as of December 19, 2001, as
it may be amended, supplemented or otherwise modified from time to time, whether
prior to or after the date hereof.

      "BROADBAND INDENTURE" shall refer to the indenture dated as of [ ], 2002,
among Broadband, as issuer, the Cable Guarantors party thereto and The Bank of
New York, as trustee, pursuant to which the New Broadband Notes will be issued
in exchange for the Notes.

      Upon completion of the Mandatory Exchange with respect to Notes and
payment in full of all interest payable pursuant to the eleventh paragraph of
this reverse of this Note, the Issuers


                                       30

shall be fully and completely discharged and released from their obligations
under the Indenture and the Notes with respect to the Notes, including their
obligations for the payment of principal and interest on the Notes.

      If the Merger Agreement is terminated and the Mergers (as defined therein)
are abandoned at any time prior to the Effective Time, (a) Broadband shall be
fully and completely released from its obligations under the Indenture and the
Notes with respect to the Notes, including its obligations for the payment of
principal and interest on the Notes, and (b) the Notes shall cease to be
exchangeable for the New Broadband Notes.

      The Notes will be redeemable, as a whole or in part, at the option of the
Issuers, at any time or from time to time, on at least 30 days, but not more
than 60 days, prior notice mailed to the registered address of each holder of
the Notes. The redemption prices will be equal to the greater of (1) 100% of the
principal amount of the Notes to be redeemed or (2) the sum of the present
values of the Remaining Scheduled Payments (as defined below) discounted, on a
semiannual basis (assuming a 360-day year consisting of twelve 30-day months),
at a rate equal to the sum of the Treasury Rate (as defined below) and 15 basis
points.

      In the case of each of clause (1) and (2), accrued interest will be
payable to the redemption date.

      "Treasury Rate" means, with respect to any redemption date, the rate per
annum equal to the semiannual equivalent yield to maturity of the Comparable
Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as
a percentage of its principal amount) equal to the Comparable Treasury Price for
such redemption date.

      "Comparable Treasury Issue" means the United States Treasury security
selected by an Independent Investment Banker as having a maturity comparable to
the remaining term of the Notes to be redeemed that would be utilized, at the
time of selection and in accordance with customary financial practice, in
pricing new issues of corporate debt securities of comparable maturity to the
remaining term of such Notes. "Independent Investment Banker" means one of the
Reference Treasury Dealers appointed by the Issuers.

      "Comparable Treasury Price" means, with respect to any redemption date,
(1) the average of the Reference Treasury Dealer Quotations for such redemption
date after excluding the highest and lowest of such Reference Treasury Dealer
Quotations, or (2) if the Trustee obtains fewer than five such Reference
Treasury Dealer Quotations, the average of all such quotations. "Reference
Treasury Dealer Quotations" means, with respect to each Reference Treasury
Dealer and any redemption date, the average, as determined by the Trustee, of
the bid and asked prices for the Comparable Treasury Issue (expressed in each
case as a percentage of its principal amount) quoted in writing to the Trustee
by such Reference Treasury Dealer at 3:30 p.m., New York City time, on the third
business day preceding such redemption date.

      "Reference Treasury Dealer" means each of Merrill Lynch, Pierce, Fenner &
Smith Incorporated, Salomon Smith Barney Inc., Deutsche Bank Securities Inc.,
Banc One Capital Markets Inc., Lehman Brothers Inc., J.P. Morgan Securities Inc.
and Banc of America Securities LLC and their respective successors. If any of
the foregoing shall cease to be a primary U.S.


                                       31

Government securities dealer (a "Primary Treasury Dealer"), the Issuers shall
substitute another nationally recognized investment banking firm that is a
Primary Treasury Dealer.

      "Remaining Scheduled Payments" means, with respect to each Note to be
redeemed, the remaining scheduled payments of principal of and interest on such
Note that would be due after the related redemption date but for such
redemption. If such redemption date is not an interest payment date with respect
to such Note, the amount of the next succeeding scheduled interest payment on
such Note will be reduced by the amount of interest accrued on such Note to such
redemption date.

      The Issuers will, subject to the exceptions and limitations set forth
below, pay as additional interest on the Notes such additional amounts as are
necessary so that the net payment by the Issuers or a paying agent of the
principal of, premium, if any, and interest on the Notes to a person that is not
a United States Holder (as defined below), after deduction for any present or
future tax, assessment or governmental charge of the United States or a
political subdivision or taxing authority thereof or therein, imposed by
withholding with respect to the payment, will not be less than the amount that
would have been payable in respect of the Notes had no such withholding or
deduction been required.

      As used herein, a "United States Holder" of a note means a beneficial
owner that is for United States federal income tax purposes: (a) a citizen or
resident of the United States, (b) a corporation, partnership or other entity
created or organized in or under the laws of the United States or of any
political subdivision thereof, (c) an estate or trust the income of which is
subject to United States federal income taxation regardless of its source or (d)
any other person whose income from a note is effectively connected with the
conduct of a United States trade or business.

      The Issuers' obligations to pay additional amounts will not apply:

      1. to a tax, assessment or governmental charge that is imposed or withheld
solely because the holder, or a fiduciary, settlor, beneficiary, member or
shareholder of the holder if the holder is an estate, trust, partnership or
corporation, or a person holding a power over an estate or trust administered by
a fiduciary holder:

            (a) is or was present or engaged in trade or business in the United
      States or has or had a permanent establishment in the United States;

            (b) has a current or former relationship with the United States,
      including a relationship as a citizen or resident thereof;

            (c) is or has been a foreign or domestic personal holding company, a
      passive foreign investment company or a controlled foreign corporation
      with respect to the United States or a corporation that has accumulated
      earnings to avoid United States federal income tax; or

            (d) is or was a "10-percent shareholder" of the Issuers as defined
      in section 871(h) (3) of the United States Internal Revenue Code or any
      successor provision;


                                       32

      2. to any holder that is not the sole beneficial owner of the Notes, or a
portion thereof, or that is a fiduciary or partnership, but only to the extent
that the beneficial owner, a beneficiary or settlor with respect to the
fiduciary, or a member of the partnership would not have been entitled to the
payment of an additional amount had such beneficial owner, beneficiary, settlor
or member received directly its beneficial or distributive share of the payment;

      3. to a tax, assessment or governmental charge that is imposed or withheld
solely because the holder or any other person failed to comply with
certification, identification or information reporting requirements concerning
the nationality, residence, identity or connection with the United States of the
holder or beneficial owner of the Notes, if compliance is required by statute,
by regulation of the United States Treasury Department or by an applicable
income tax treaty to which the United States is a party as a precondition to
exemption from such tax, assessment or other governmental charge;

      4. to a tax, assessment or governmental charge that is imposed other than
by withholding by the Issuers or a paying agent from the payment;

      5. to a tax, assessment or governmental charge that is imposed or withheld
solely because of a change in law, regulation, or administrative or judicial
interpretation that becomes effective more than 15 days after the payment
becomes due or is duly provided for, whichever occurs later;

      6. to an estate, inheritance, gift, sales, excise, transfer, wealth or
personal property tax or a similar tax, assessment or governmental charge;

      7. to any tax, assessment or other governmental charge any payment agent
must withhold from any payment of principal of, premium if any, or interest on
any Notes, if such payment can be made without such withholding by any other
paying agent; or

      8. in the case of any combination of the above items.

      The Notes are subject in all cases to any tax, fiscal or other law or
regulation or administrative or judicial interpretation applicable. Except as
specifically provided herein, the Issuers do not have to make any payment with
respect to any tax, assessment or governmental charge imposed by any government
or a political subdivision or taxing authority.

      If (a) the Issuers become or will become obligated to pay additional
amounts as described above as a result of any change in, or amendment to, the
laws (or any regulations or rulings promulgated thereunder) of the United States
(or any political subdivision or taxing authority thereof or therein), or any
change in, or amendments to, any official position regarding the application or
interpretation of such laws, regulations or rulings, which change or amendment
is announced or becomes effective on or after March 23, 1999, or (b) a taxing
authority of the United States takes an action on or after March 23, 1999,
whether or not with respect to each of the Issuers or any of its affiliates,
that results in a substantial probability that the Issuers will or may be
required to pay such additional amounts, then each of the Issuers may, at its
option, redeem, as a whole, but not in part, the Notes on any interest payment
date on not less than 30 nor more than 60 calendar days' prior notice, at a
redemption price equal to 100% of their principal amount, together with interest
accrued thereon to the date fixed for redemption,


                                       33

provided that each of the Issuers determines, in its business judgment, that the
obligation to pay such additional amounts cannot be avoided by the use of
reasonable measures available to the Issuers, not including substitution of the
obligor under the Notes. No redemption pursuant to (b) above may be made unless
each of the Issuers has received an opinion of independent counsel to the effect
than an act taken by a taxing authority of the United States results in a
substantial probability that the Issuers will or may be required to pay the
additional amounts described herein and delivered to the Trustee a certificate,
signed by a duly authorized officer stating, that based on such opinion each of
the Issuers is entitled to redeem the notes pursuant to their terms.

      Upon due presentment for registration of transfer of this Note at the
above-mentioned office or agency of the Trustee, a new Global Security or Notes
of authorized denominations, for a like aggregate principal amount will be
issued to the transferee as provided in the Indenture. No service charge shall
be made for any such transfer, but the Issuers may require payment of a sum
sufficient to cover any tax or other governmental charge that may be imposed in
relation thereto.

      The Issuers, the Trustee, and any agent of the either Issuer or the
Trustee may deem and treat the Holder hereof as the absolute owner hereof
(whether or not this Global Security shall be overdue and notwithstanding any
notation of ownership or other writing hereon) for the purpose of receiving
payment of or on account of the principal hereof and subject to the provisions
above, of premium or interest thereon, and for all other purposes and neither
the Issuers nor the Trustee nor any such agent shall be affected by any notice
to the contrary.

      No recourse shall be had for the payment of the principal of, premium, if
any, or the interest on, this Global Security or for any claim based hereon, or
otherwise in respect hereof, or based on or in respect of the Indenture or any
indenture supplemental thereto, against any incorporator, shareholder, officer
or director as such, past, present or future, of the Issuers or of any successor
corporation, either directly or through the Issuers or of any successor
corporation whether by virtue of any constitution, statute or rule of law or by
the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

      This Global Security shall be deemed to be a contract made under the laws
of the State of New York and for all purposes shall be governed by and construed
in accordance with the laws of said State.

      Unless otherwise defined in this Global Security, all terms used in this
Global Security which are defined in the Indenture shall have the meanings
assigned to them in the Indenture.


                                       34

                                  ABBREVIATIONS

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

      TEN COM     - as tenants in common

      TEN ENT     - as tenants by the entireties

      JT TEN      - as joint tenants with right of survivorship and not as
                    tenants in common

      UNIF GIFT MIN ACT - ________________(Cust)___________(Minor)

      Under Uniform Gifts to Minor Act ________________(State)

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

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

[PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE]

______________________________________________________________________________

______________________________________________________________________________

[PLEASE PRINT OR TYPE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE]

______________________________________________________________________________

______________________________________________________________________________

the within Notes and all rights thereunder, hereby irrevocably constituting and
appointing such person attorney to transfer such Note on the books of the
Issuers, with full power of substitution in the premises.

Date:


NOTICE:     The signature of this assignment must correspond with the name as
            written upon the face of the within Notes in every particular
            without alteration or enlargement or any change whatsoever.


                                       35

         [FORM OF 8.125% BROADBAND EXCHANGE NOTES DUE JANUARY 15, 2022]

                 PERMANENT GLOBAL REGISTERED FIXED RATE SECURITY

      THIS NOTE IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HERINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE THEREOF. UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES
IN CERTIFICATED FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC") TO A NOMINEE OF DTC OR
BY DTC OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC TO AT&T CORP. AND AT&T BROADBAND CORP. OR ITS AGENTS FOR
REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY NOTE ISSUED IS REGISTERED
IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS 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.

                                   AT&T CORP.

                              AT&T BROADBAND CORP.

              8.125% Broadband Exchange Notes Due January 15, 2022

REGISTERED [               ]                   CUSIP No. [               ]

      AT&T Corp., a New York corporation ("AT&T") and AT&T Broadband Corp., a
Delaware corporation ("BROADBAND," and with AT&T, each an "ISSUER" and
collectively, the "ISSUERS"), for value received, hereby jointly and severally
promise to pay to CEDE & CO. or registered assigns the principal sum of [ ] on
January 15, 2022, and to pay interest semiannually on January 15 and July 15,
commencing [ ], on said principal sum at the rate per annum specified in the
title of these Notes, from [ ] until the principal thereof is paid or made
available for payment.

      For purposes of this Note, "Company" within the meaning of the Indenture
referred to herein shall mean each Issuer.

      Reference is hereby made to the further provisions of this global security
(the "GLOBAL SECURITY") set forth on the reverse hereof, which further
provisions shall for all purposes have the same effect as if set forth in this
place.

      This Global Security shall not be valid or become obligatory for any
purpose until the certificate of authentication hereon shall have been executed
by the Trustee under the Indenture referred to herein.


                                       36

      IN WITNESS WHEREOF, each Issuer has caused this Global Security to be duly
executed under its corporate seal.

Dated:  [                    ], 2002

                                   AT&T Corp.


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

                                   Attest:


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


                                   AT&T Broadband Corp.


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

                                   Attest:


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

TRUSTEE'S CERTIFICATE OF
AUTHENTICATION

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

THE BANK OF NEW YORK,
  As Trustee

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


                                       37

                                REVERSE OF NOTES

      The Issuers, jointly and severally, agree to pay the principal of,
premium, if any, and interest on, this Global Security in immediately available
funds at the office or agency of the Trustee maintained for that purpose in the
Borough of Manhattan, The City of New York, State of New York, in such coin or
currency of the United States of America as at the time of payment shall be
legal tender for payment of public and private debts; provided, however, that at
the option of the Issuers payment of interest on any Notes issued in definitive
form other than interest due at the Maturity Date shown above may be made by
check mailed to the address of the person entitled thereto as such address shall
appear in the Note register. Interest will be paid to persons in whose names the
Notes are registered at the close of business on the January 1 or July 1, as the
case may be, prior to any interest payment date. Except as otherwise set forth
in the Indenture, Notes in definitive form will not be issued.

      This Note is one of a duly authorized issue of securities of the Issuers,
issued and to be issued under and pursuant to an indenture, dated as of
September 7, 1990, between AT&T and The Bank of New York, as Trustee under
Indenture (herein referred to as the "TRUSTEE"), as amended by the First
Supplemental Indenture, dated as of October 30, 1992, between AT&T and the
Trustee, the Second Supplemental Indenture, dated as of [ ], 2002, between AT&T
and the Trustee, and the Third Supplemental Indenture, dated as of [ ], 2002,
among the Issuers and the Trustee (herein referred to as the "Indenture"), duly
executed and delivered by the Issuers to the Trustee, to which Indenture and all
indentures supplemental thereto reference is hereby made for description of the
rights, limitations of rights, obligations, duties and immunities thereunder of
the Trustee, the Issuers and the Holder (the words "HOLDERS" or "HOLDER" meaning
the registered holders or registered holder) of these Notes. To the extent the
terms of the Indenture and this Note are inconsistent, the terms of the
Indenture shall govern.

      In case an Event of Default with respect to the Notes, as defined in the
Indenture, shall have occurred and be continuing, the principal hereof may be
declared, and upon such declaration shall become due and payable in the manner,
with the effect and subject to the conditions provided in the Indenture.

      The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Issuers and the rights of the Holders of the Notes to be affected under the
Indenture at any time by the Issuers and the Trustee with the consent of the
Holders of a majority in principal amount of the outstanding Notes. The
Indenture also contains provisions permitting the Holders of not less than a
majority in principal amount of the outstanding Notes, on behalf of the Holders
of all Notes, to waive compliance by the Issuers with certain provisions of the
Indenture. The Indenture also provides that the Holders of not less than a
majority in principal amount of the outstanding Notes may waive certain past
defaults and their consequences on behalf of the Holders of all Notes. Any such
consent or waiver by the Holder of any Note shall be conclusive and binding upon
such Holder and upon all future Holders of such Note and of any Note issued upon
registration of transfer hereof or in exchange herefor or in lieu hereof whether
or not notation of such consent or waiver is made upon such Note.

     The Indenture also provides that the Covered Transactions (as defined in
the Indenture), individually or together, (a) will not result in a
consolidation, merger, sale, conveyance or other transfer of property of


                                       38

any Issuer (including stock of subsidiaries) as an entirety or substantially as
an entirety for purposes of Section 5.01 of the Indenture or any other provision
of the Indenture or these Notes, and (b) will not violate Sections 5.01, 5.02 or
5.03 of the Indenture or any other provision of the Indenture or these Notes,
regardless of whether any person assumes any of the indebtedness outstanding
under the Indenture or any other obligation under the Indenture or these Notes.

      The Indenture contains provisions setting forth certain conditions to the
institution of proceedings by Holders of Notes with respect to the Indenture or
for any remedy under the Indenture.

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

      The Notes are issuable as registered Notes without coupons in
denominations of U.S. $1,000 or any amount in excess thereof which is a multiple
of U.S. $1,000 at the office or agency of the Trustee referred to above and in
the manner and subject to the limitations provided in the Indenture. Notes may
be exchanged without service charge for like aggregate principal amount of
Notes.

      At the Effective Time (as defined in the Merger Agreement), each $1,000
principal amount of Notes shall be mandatorily exchanged (the "MANDATORY
EXCHANGE") for $[ ] principal amount of [ ]% Notes Due [ ], 2022 ("NEW BROADBAND
NOTES").

      New Broadband Notes shall only be issued in denominations of $1,000 and
multiples of $1,000. If the Mandatory Exchange would result in a Holder being
entitled to receive a fractional interest in the New Broadband Notes, the
principal amount such Holder shall receive shall be rounded down to the nearest
$1,000 multiple and such Holder shall receive cash in lieu of a fractional New
Broadband Note for the balance.

      Interest accrued and unpaid on the Notes shall be paid on the date of the
Mandatory Exchange.

      Each Holder of the Notes is deemed, by virtue of having acquired such
Notes, to have expressly and irrevocably consented to the Mandatory Exchange.

      "MERGER AGREEMENT" means the Agreement and Plan of Merger by and among the
Issuers, Comcast Corporation, AT&T Broadband Acquisition Corp., Comcast
Acquisition Corp. and AT&T Comcast Corporation dated as of December 19, 2001, as
it may be amended, supplemented or otherwise modified from time to time, whether
prior to or after the date hereof.

      "BROADBAND INDENTURE" shall refer to the indenture dated as of [ ], 2002,
among Broadband, as issuer, the Cable Guarantors party thereto and The Bank of
New York, as trustee, pursuant to which the New Broadband Notes will be issued
in exchange for the Notes.

      Upon completion of the Mandatory Exchange with respect to Notes and
payment in full of all interest payable pursuant to the eleventh paragraph of
this reverse of this Note, the Issuers


                                       39

shall be fully and completely discharged and released from their obligations
under the Indenture and the Notes with respect to the Notes, including their
obligations for the payment of principal and interest on the Notes.

      If the Merger Agreement is terminated and the Mergers (as defined therein)
are abandoned at any time prior to the Effective Time, (a) Broadband shall be
fully and completely released from its obligations under the Indenture and the
Notes with respect to the Notes, including its obligations for the payment of
principal and interest on the Notes, and (b) the Notes shall cease to be
exchangeable for the New Broadband Notes.

      The Notes may be redeemed, at the option of the Issuers at any time or
from time to time prior to maturity, as a whole or in part, upon the notice
referred to below, at the following redemption prices (expressed in percentages
of the principal amount) during the 12 month periods beginning January 15:


                                             
            2002......................          103.21%
            2003......................          102.89%
            2004......................          102.57%
            2005......................          102.25%
            2006......................          101.93%
            2007......................          101.60%
            2008......................          101.28%
            2009......................          100.96%
            2010......................          100.64%
            2011......................          100.32%


and thereafter at 100%, together in each case with accrued interest to the date
fixed for redemption. As provided in the Indenture, notice of redemption to the
holders of Notes to be redeemed as a whole or in part shall be given by mailing
a notice of such redemption not less than thirty nor more than sixty days prior
to the date fixed for redemption to their last addresses as they shall appear
upon the register kept for that purpose.

      Upon due presentment for registration of transfer of this Note at the
above-mentioned office or agency of the Trustee, a new Global Security or Notes
of authorized denominations, for a like aggregate principal amount will be
issued to the transferee as provided in the Indenture. No service charge shall
be made for any such transfer, but the Issuers may require payment of a sum
sufficient to cover any tax or other governmental charge that may be imposed in
relation thereto.

      The Issuers, the Trustee, and any agent of the either Issuer or the
Trustee may deem and treat the Holder hereof as the absolute owner hereof
(whether or not this Global Security shall be overdue and notwithstanding any
notation of ownership or other writing hereon) for the purpose of receiving
payment of or on account of the principal hereof and subject to the provisions
above, of premium or interest thereon, and for all other purposes and neither
the Issuers nor the Trustee nor any such agent shall be affected by any notice
to the contrary.


                                       40

      No recourse shall be had for the payment of the principal of, premium, if
any, or the interest on, this Global Security or for any claim based hereon, or
otherwise in respect hereof, or based on or in respect of the Indenture or any
indenture supplemental thereto, against any incorporator, shareholder, officer
or director as such, past, present or future, of the Issuers or of any successor
corporation, either directly or through the Issuers or of any successor
corporation whether by virtue of any constitution, statute or rule of law or by
the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

      This Global Security shall be deemed to be a contract made under the laws
of the State of New York and for all purposes shall be governed by and construed
in accordance with the laws of said State.

      Unless otherwise defined in this Global Security, all terms used in this
Global Security which are defined in the Indenture shall have the meanings
assigned to them in the Indenture.


                                       41

                                  ABBREVIATIONS

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

      TEN COM - as tenants in common

      TEN ENT - as tenants by the entireties

      JT TEN  - as joint tenants with right of survivorship and not as
                tenants in common

      UNIF GIFT MIN ACT - ________________(Cust)___________(Minor)

      Under Uniform Gifts to Minor Act ________________(State)

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

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

[PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE]

_______________________________________________________________________________

_______________________________________________________________________________

[PLEASE PRINT OR TYPE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE]

_______________________________________________________________________________

_______________________________________________________________________________

the within Notes and all rights thereunder, hereby irrevocably constituting and
appointing such person attorney to transfer such Note on the books of the
Issuers, with full power of substitution in the premises.

Date:


NOTICE:     The signature of this assignment must correspond with the name as
            written upon the face of the within Notes in every particular
            without alteration or enlargement or any change whatsoever.


                                       42

           [FORM OF 8.125% BROADBAND EXCHANGE NOTES DUE JULY 15, 2024]

                 PERMANENT GLOBAL REGISTERED FIXED RATE SECURITY

      THIS NOTE IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HERINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE THEREOF. UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES
IN CERTIFICATED FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC") TO A NOMINEE OF DTC OR
BY DTC OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC TO AT&T CORP. AND AT&T BROADBAND CORP. OR ITS AGENTS FOR
REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY NOTE ISSUED IS REGISTERED
IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS 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.

                                   AT&T CORP.

                              AT&T BROADBAND CORP.

                8.125% Broadband Exchange Notes Due July 15, 2024

REGISTERED [               ]                 CUSIP No. [               ]

      AT&T Corp., a New York corporation ("AT&T") and AT&T Broadband Corp., a
Delaware corporation ("BROADBAND," and with AT&T, each an "ISSUER" and
collectively, the "ISSUERS"), for value received, hereby jointly and severally
promise to pay to CEDE & CO. or registered assigns the principal sum of [ ] on
July 15, 2024, and to pay interest semiannually on January 15 and July 15,
commencing [ ], on said principal sum at the rate per annum specified in the
title of these Notes, from [ ] until the principal thereof is paid or made
available for payment.

      For purposes of this Note, "Company" within the meaning of the Indenture
referred to herein shall mean each Issuer.

      Reference is hereby made to the further provisions of this global security
(the "GLOBAL SECURITY") set forth on the reverse hereof, which further
provisions shall for all purposes have the same effect as if set forth in this
place.

      This Global Security shall not be valid or become obligatory for any
purpose until the certificate of authentication hereon shall have been executed
by the Trustee under the Indenture referred to herein.


                                       43

      IN WITNESS WHEREOF, each Issuer has caused this Global Security to be duly
executed under its corporate seal.

Dated:  [                    ], 2002

                                   AT&T Corp.


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

                                   Attest:


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


                                   AT&T Broadband Corp.


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

                                   Attest:


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

TRUSTEE'S CERTIFICATE OF
AUTHENTICATION

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

THE BANK OF NEW YORK,
  As Trustee

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


                                       44

                                REVERSE OF NOTES

      The Issuers, jointly and severally, agree to pay the principal of,
premium, if any, and interest on, this Global Security in immediately available
funds at the office or agency of the Trustee maintained for that purpose in the
Borough of Manhattan, The City of New York, State of New York, in such coin or
currency of the United States of America as at the time of payment shall be
legal tender for payment of public and private debts; provided, however, that at
the option of the Issuers payment of interest on any Notes issued in definitive
form other than interest due at the Maturity Date shown above may be made by
check mailed to the address of the person entitled thereto as such address shall
appear in the Note register. Interest will be paid to persons in whose names the
Notes are registered at the close of business on the January 1 or July 1, as the
case may be, prior to any interest payment date. Except as otherwise set forth
in the Indenture, Notes in definitive form will not be issued.

      This Note is one of a duly authorized issue of securities of the Issuers,
issued and to be issued under and pursuant to an indenture, dated as of
September 7, 1990, between AT&T and The Bank of New York, as Trustee under
Indenture (herein referred to as the "TRUSTEE"), as amended by the First
Supplemental Indenture, dated as of October 30, 1992, between AT&T and the
Trustee, the Second Supplemental Indenture, dated as of [ ], 2002, between AT&T
and the Trustee, and the Third Supplemental Indenture, dated as of [ ], 2002,
among the Issuers and the Trustee (herein referred to as the "Indenture"), duly
executed and delivered by the Issuers to the Trustee, to which Indenture and all
indentures supplemental thereto reference is hereby made for description of the
rights, limitations of rights, obligations, duties and immunities thereunder of
the Trustee, the Issuers and the Holder (the words "HOLDERS" or "HOLDER" meaning
the registered holders or registered holder) of these Notes. To the extent the
terms of the Indenture and this Note are inconsistent, the terms of the
Indenture shall govern.

      In case an Event of Default with respect to the Notes, as defined in the
Indenture, shall have occurred and be continuing, the principal hereof may be
declared, and upon such declaration shall become due and payable in the manner,
with the effect and subject to the conditions provided in the Indenture.

      The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Issuers and the rights of the Holders of the Notes to be affected under the
Indenture at any time by the Issuers and the Trustee with the consent of the
Holders of a majority in principal amount of the outstanding Notes. The
Indenture also contains provisions permitting the Holders of not less than a
majority in principal amount of the outstanding Notes, on behalf of the Holders
of all Notes, to waive compliance by the Issuers with certain provisions of the
Indenture. The Indenture also provides that the Holders of not less than a
majority in principal amount of the outstanding Notes may waive certain past
defaults and their consequences on behalf of the Holders of all Notes. Any such
consent or waiver by the Holder of any Note shall be conclusive and binding upon
such Holder and upon all future Holders of such Note and of any Note issued upon
registration of transfer hereof or in exchange herefor or in lieu hereof whether
or not notation of such consent or waiver is made upon such Note.

     The Indenture also provides that the Covered Transactions (as defined in
the Indenture), individually or together, (a) will not result in a
consolidation, merger, sale, conveyance or other transfer of property of


                                       45

any Issuer (including stock of subsidiaries) as an entirety or substantially as
an entirety for purposes of Section 5.01 of the Indenture or any other provision
of the Indenture or these Notes, and (b) will not violate Sections 5.01, 5.02 or
5.03 of the Indenture or any other provision of the Indenture or these Notes,
regardless of whether any person assumes any of the indebtedness outstanding
under the Indenture or any other obligation under the Indenture or these Notes.

      The Indenture contains provisions setting forth certain conditions to the
institution of proceedings by Holders of Notes with respect to the Indenture or
for any remedy under the Indenture.

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

      The Notes are issuable as registered Notes without coupons in
denominations of U.S. $1,000 or any amount in excess thereof which is a multiple
of U.S. $1,000 at the office or agency of the Trustee referred to above and in
the manner and subject to the limitations provided in the Indenture. Notes may
be exchanged without service charge for like aggregate principal amount of
Notes.

      At the Effective Time (as defined in the Merger Agreement), each $1,000
principal amount of Notes shall be mandatorily exchanged (the "MANDATORY
EXCHANGE") for $[ ] principal amount of [ ]% Notes Due [ ], 2022 ("NEW BROADBAND
NOTES").

      New Broadband Notes shall only be issued in denominations of $1,000 and
multiples of $1,000. If the Mandatory Exchange would result in a Holder being
entitled to receive a fractional interest in the New Broadband Notes, the
principal amount such Holder shall receive shall be rounded down to the nearest
$1,000 multiple and such Holder shall receive cash in lieu of a fractional New
Broadband Note for the balance.

      Interest accrued and unpaid on the Notes shall be paid on the date of the
Mandatory Exchange.

      Each Holder of the Notes is deemed, by virtue of having acquired such
Notes, to have expressly and irrevocably consented to the Mandatory Exchange.

      "MERGER AGREEMENT" means the Agreement and Plan of Merger by and among the
Issuers, Comcast Corporation, AT&T Broadband Acquisition Corp., Comcast
Acquisition Corp. and AT&T Comcast Corporation dated as of December 19, 2001, as
it may be amended, supplemented or otherwise modified from time to time, whether
prior to or after the date hereof.

      "BROADBAND INDENTURE" shall refer to the indenture dated as of [ ], 2002,
among Broadband, as issuer, the Cable Guarantors party thereto and The Bank of
New York, as trustee, pursuant to which the New Broadband Notes will be issued
in exchange for the Notes.

      Upon completion of the Mandatory Exchange with respect to Notes and
payment in full of all interest payable pursuant to the eleventh paragraph of
this reverse of this Note, the Issuers


                                       46

shall be fully and completely discharged and released from their obligations
under the Indenture and the Notes with respect to the Notes, including their
obligations for the payment of principal and interest on the Notes.

      If the Merger Agreement is terminated and the Mergers (as defined therein)
are abandoned at any time prior to the Effective Time, (a) Broadband shall be
fully and completely released from its obligations under the Indenture and the
Notes with respect to the Notes, including its obligations for the payment of
principal and interest on the Notes, and (b) the Notes shall cease to be
exchangeable for the New Broadband Notes.

      The Notes may be redeemed, at the option of the Issuers at any time or
from time to time prior to maturity, as a whole or in part, upon the notice
referred to below, at the following redemption prices (expressed in percentages
of the principal amount) during the 12 month periods beginning July 15:


                                         
            2002.....................       103.971%
            2003.....................       103.640%
            2004.....................       103.309%
            2005.....................       102.978%
            2006.....................       102.647%
            2007.....................       102.316%
            2008.....................       101.985%
            2009.....................       101.655%
            2010.....................       101.324%
            2011.....................       100.993%
            2012.....................       100.662%
            2013.....................       100.331%


and thereafter at 100%, together in each case with accrued interest to the date
fixed for redemption. As provided in the Indenture, notice of redemption to the
holders of Notes to be redeemed as a whole or in part shall be given by mailing
a notice of such redemption not less than thirty nor more than sixty days prior
to the date fixed for redemption to their last addresses as they shall appear
upon the register kept for that purpose.

      Upon due presentment for registration of transfer of this Note at the
above-mentioned office or agency of the Trustee, a new Global Security or Notes
of authorized denominations, for a like aggregate principal amount will be
issued to the transferee as provided in the Indenture. No service charge shall
be made for any such transfer, but the Issuers may require payment of a sum
sufficient to cover any tax or other governmental charge that may be imposed in
relation thereto.

      The Issuers, the Trustee, and any agent of the either Issuer or the
Trustee may deem and treat the Holder hereof as the absolute owner hereof
(whether or not this Global Security shall be overdue and notwithstanding any
notation of ownership or other writing hereon) for the purpose of receiving
payment of or on account of the principal hereof and subject to the provisions
above, of premium or interest thereon, and for all other purposes and neither
the Issuers nor the Trustee nor any such agent shall be affected by any notice
to the contrary.


                                       47

      No recourse shall be had for the payment of the principal of, premium, if
any, or the interest on, this Global Security or for any claim based hereon, or
otherwise in respect hereof, or based on or in respect of the Indenture or any
indenture supplemental thereto, against any incorporator, shareholder, officer
or director as such, past, present or future, of the Issuers or of any successor
corporation, either directly or through the Issuers or of any successor
corporation whether by virtue of any constitution, statute or rule of law or by
the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

      This Global Security shall be deemed to be a contract made under the laws
of the State of New York and for all purposes shall be governed by and construed
in accordance with the laws of said State.

      Unless otherwise defined in this Global Security, all terms used in this
Global Security which are defined in the Indenture shall have the meanings
assigned to them in the Indenture.


                                       48



                                  ABBREVIATIONS

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

      TEN COM - as tenants in common

      TEN ENT - as tenants by the entireties

      JT TEN  - as joint tenants with right of survivorship and not as tenants
                in common

      UNIF GIFT MIN ACT - ________________(Cust)___________(Minor)

      Under Uniform Gifts to Minor Act ________________(State)

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

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

[PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE]

________________________________________________________________________________

[PLEASE PRINT OR TYPE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE]

________________________________________________________________________________

the within Notes and all rights thereunder, hereby irrevocably constituting and
appointing such person attorney to transfer such Note on the books of the
Issuers, with full power of substitution in the premises.

Date:


NOTICE:     The signature of this assignment must correspond with the name as
            written upon the face of the within Notes in every particular
            without alteration or enlargement or any change whatsoever.


                                       49

                [FORM OF 8.35% BROADBAND EXCHANGE NOTES DUE 2025]

                 PERMANENT GLOBAL REGISTERED FIXED RATE SECURITY

      THIS NOTE IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HERINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE THEREOF. UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES
IN CERTIFICATED FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC") TO A NOMINEE OF DTC OR
BY DTC OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC TO AT&T CORP. AND AT&T BROADBAND CORP. OR ITS AGENTS FOR
REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY NOTE ISSUED IS REGISTERED
IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS 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.

                                        AT&T CORP.

                                   AT&T BROADBAND CORP.

                         8.35% Broadband Exchange Notes Due 2025

REGISTERED [       ]                                CUSIP No. [        ]

      AT&T Corp., a New York corporation ("AT&T") and AT&T Broadband Corp., a
Delaware corporation ("BROADBAND," and with AT&T, each an "ISSUER" and
collectively, the "Issuers"), for value received, hereby jointly and severally
promise to pay to CEDE & CO. or registered assigns the principal sum of [ ] on
January 15, 2025, and to pay interest semiannually on January 15 and July 15,
commencing [ ], on said principal sum at the rate per annum specified in the
title of these Notes, from [ ] until the principal thereof is paid or made
available for payment.

      For purposes of this Note, "Company" within the meaning of the Indenture
referred to herein shall mean each Issuer.

      Reference is hereby made to the further provisions of this global security
(the "GLOBAL SECURITY") set forth on the reverse hereof, which further
provisions shall for all purposes have the same effect as if set forth in this
place.

      This Global Security shall not be valid or become obligatory for any
purpose until the certificate of authentication hereon shall have been executed
by the Trustee under the Indenture referred to herein.


                                       50

      IN WITNESS WHEREOF, each Issuer has caused this Global Security to be duly
executed under its corporate seal.

Dated:  [       ], 2002

                                   AT&T Corp.


                                   By: __________________________________
                                       Name:
                                       Title:

                                   Attest:


                                   By: __________________________________
                                       Name:
                                       Title:


                                   AT&T Broadband Corp.


                                   By: __________________________________
                                       Name:
                                       Title:

                                   Attest:


                                   By: __________________________________
                                       Name:
                                       Title:

TRUSTEE'S CERTIFICATE OF
AUTHENTICATION

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

THE BANK OF NEW YORK,
  As Trustee

By: ________________________________
      Authorized Signatory


                                       51

                                REVERSE OF NOTES

      The Issuers, jointly and severally, agree to pay the principal of,
premium, if any, and interest on, this Global Security in immediately available
funds at the office or agency of the Trustee maintained for that purpose in the
Borough of Manhattan, The City of New York, State of New York, in such coin or
currency of the United States of America as at the time of payment shall be
legal tender for payment of public and private debts; provided, however, that at
the option of the Issuers payment of interest on any Notes issued in definitive
form other than interest due at the Maturity Date shown above may be made by
check mailed to the address of the person entitled thereto as such address shall
appear in the Note register. Interest will be paid to persons in whose names the
Notes are registered at the close of business on the January 1 or July 1, as the
case may be, prior to any interest payment date. Except as otherwise set forth
in the Indenture, Notes in definitive form will not be issued.

      This Note is one of a duly authorized issue of securities of the Issuers,
issued and to be issued under and pursuant to an indenture, dated as of
September 7, 1990, between AT&T and The Bank of New York, as Trustee under
Indenture (herein referred to as the "TRUSTEE"), as amended by the First
Supplemental Indenture, dated as of October 30, 1992, between AT&T and the
Trustee, the Second Supplemental Indenture, dated as of [       ], 2002,
between AT&T and the Trustee, and the Third Supplemental Indenture, dated as of
[       ], 2002, among the Issuers and the Trustee (herein referred to as the
"INDENTURE"), duly executed and delivered by the Issuers to the Trustee, to
which Indenture and all indentures supplemental thereto reference is hereby made
for description of the rights, limitations of rights, obligations, duties and
immunities thereunder of the Trustee, the Issuers and the Holder (the words
"HOLDERS" or "HOLDER" meaning the registered holders or registered holder) of
these Notes. To the extent the terms of the Indenture and this Note are
inconsistent, the terms of the Indenture shall govern.

      In case an Event of Default with respect to the Notes, as defined in the
Indenture, shall have occurred and be continuing, the principal hereof may be
declared, and upon such declaration shall become due and payable in the manner,
with the effect and subject to the conditions provided in the Indenture.

      The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Issuers and the rights of the Holders of the Notes to be affected under the
Indenture at any time by the Issuers and the Trustee with the consent of the
Holders of a majority in principal amount of the outstanding Notes. The
Indenture also contains provisions permitting the Holders of not less than a
majority in principal amount of the outstanding Notes, on behalf of the Holders
of all Notes, to waive compliance by the Issuers with certain provisions of the
Indenture. The Indenture also provides that the Holders of not less than a
majority in principal amount of the outstanding Notes may waive certain past
defaults and their consequences on behalf of the Holders of all Notes. Any such
consent or waiver by the Holder of any Note shall be conclusive and binding upon
such Holder and upon all future Holders of such Note and of any Note issued upon
registration of transfer hereof or in exchange herefor or in lieu hereof whether
or not notation of such consent or waiver is made upon such Note.

     The Indenture also provides that the Covered Transactions (as defined in
the Indenture), individually or together, (a) will not result in a
consolidation, merger, sale, conveyance or other transfer of property of


                                       52

any Issuer (including stock of subsidiaries) as an entirety or substantially as
an entirety for purposes of Section 5.01 of the Indenture or any other provision
of the Indenture or these Notes, and (b) will not violate Sections 5.01, 5.02 or
5.03 of the Indenture or any other provision of the Indenture or these Notes,
regardless of whether any person assumes any of the indebtedness outstanding
under the Indenture or any other obligation under the Indenture or these Notes.

      The Indenture contains provisions setting forth certain conditions to the
institution of proceedings by Holders of Notes with respect to the Indenture or
for any remedy under the Indenture.

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

      The Notes are issuable as registered Notes without coupons in
denominations of U.S. $1,000 or any amount in excess thereof which is a multiple
of U.S. $1,000 at the office or agency of the Trustee referred to above and in
the manner and subject to the limitations provided in the Indenture. Notes may
be exchanged without service charge for like aggregate principal amount of
Notes.

      At the Effective Time (as defined in the Merger Agreement), each $1,000
principal amount of Notes shall be mandatorily exchanged (the "MANDATORY
EXCHANGE") for $[      ] principal amount of [       ]% Notes Due [      ], 2022
("NEW BROADBAND NOTES").

      New Broadband Notes shall only be issued in denominations of $1,000 and
multiples of $1,000. If the Mandatory Exchange would result in a Holder being
entitled to receive a fractional interest in the New Broadband Notes, the
principal amount such Holder shall receive shall be rounded down to the nearest
$1,000 multiple and such Holder shall receive cash in lieu of a fractional New
Broadband Note for the balance.

      Interest accrued and unpaid on the Notes shall be paid on the date of the
Mandatory Exchange.

      Each Holder of the Notes is deemed, by virtue of having acquired such
Notes, to have expressly and irrevocably consented to the Mandatory Exchange.

      "MERGER AGREEMENT" means the Agreement and Plan of Merger by and among the
Issuers, Comcast Corporation, AT&T Broadband Acquisition Corp., Comcast
Acquisition Corp. and AT&T Comcast Corporation dated as of December 19, 2001, as
it may be amended, supplemented or otherwise modified from time to time, whether
prior to or after the date hereof.

      "BROADBAND INDENTURE" shall refer to the indenture dated as of [ ], 2002,
among Broadband, as issuer, the Cable Guarantors party thereto and The Bank of
New York, as trustee, pursuant to which the New Broadband Notes will be issued
in exchange for the Notes.

      Upon completion of the Mandatory Exchange with respect to Notes and
payment in full of all interest payable pursuant to the eleventh paragraph of
this reverse of this Note, the Issuers


                                       53

shall be fully and completely discharged and released from their obligations
under the Indenture and the Notes with respect to the Notes, including their
obligations for the payment of principal and interest on the Notes.

      If the Merger Agreement is terminated and the Mergers (as defined therein)
are abandoned at any time prior to the Effective Time, (a) Broadband shall be
fully and completely released from its obligations under the Indenture and the
Notes with respect to the Notes, including its obligations for the payment of
principal and interest on the Notes, and (b) the Notes shall cease to be
exchangeable for the New Broadband Notes.

      The Notes may not be redeemed by the Issuers prior to January 15, 2005.
The Notes may be redeemed, at the option of the Issuers, as a whole or from time
to time in part, on or after January 15, 2005 and prior to maturity, upon the
notice referred to below, at the following redemption prices (expressed in
percentages of the principal amount) during the 12 month periods beginning
January 15:


                                       
            2005.....................     103.288%
            2006.....................     102.959%
            2007.....................     102.630%
            2008.....................     102.302%
            2009.....................     101.973%
            2010.....................     101.644%
            2011.....................     101.315%
            2012.....................     100.986%
            2013.....................     100.658%
            2014.....................     100.329%


and thereafter at 100%, together in each case with accrued interest to the date
fixed for redemption. As provided in the Indenture, notice of redemption to the
holders of Notes to be redeemed as a whole or in part shall be given by mailing
a notice of such redemption not less than 30 nor more than 60 days prior to the
date fixed for redemption to their last addresses as they shall appear upon the
register kept for that purpose.

      Upon due presentment for registration of transfer of this Note at the
above-mentioned office or agency of the Trustee, a new Global Security or Notes
of authorized denominations, for a like aggregate principal amount will be
issued to the transferee as provided in the Indenture. No service charge shall
be made for any such transfer, but the Issuers may require payment of a sum
sufficient to cover any tax or other governmental charge that may be imposed in
relation thereto.

      The Issuers, the Trustee, and any agent of the either Issuer or the
Trustee may deem and treat the Holder hereof as the absolute owner hereof
(whether or not this Global Security shall be overdue and notwithstanding any
notation of ownership or other writing hereon) for the purpose of receiving
payment of or on account of the principal hereof and subject to the provisions
above, of premium or interest thereon, and for all other purposes and neither
the Issuers nor the Trustee nor any such agent shall be affected by any notice
to the contrary.


                                       54

      No recourse shall be had for the payment of the principal of, premium, if
any, or the interest on, this Global Security or for any claim based hereon, or
otherwise in respect hereof, or based on or in respect of the Indenture or any
indenture supplemental thereto, against any incorporator, shareholder, officer
or director as such, past, present or future, of the Issuers or of any successor
corporation, either directly or through the Issuers or of any successor
corporation whether by virtue of any constitution, statute or rule of law or by
the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

      This Global Security shall be deemed to be a contract made under the laws
of the State of New York and for all purposes shall be governed by and construed
in accordance with the laws of said State.

      Unless otherwise defined in this Global Security, all terms used in this
Global Security which are defined in the Indenture shall have the meanings
assigned to them in the Indenture.


                                       55

                                  ABBREVIATIONS

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

      TEN COM  - as tenants in common

      TEN ENT  - as tenants by the entireties

      JT TEN   - as joint tenants with right of survivorship and not as tenants
                 in common

      UNIF GIFT MIN ACT - ________________(Cust)___________(Minor)

      Under Uniform Gifts to Minor Act ________________(State)

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

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

[PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE]

___________________________________________________________________________

[PLEASE PRINT OR TYPE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE]

___________________________________________________________________________

the within Notes and all rights thereunder, hereby irrevocably constituting and
appointing such person attorney to transfer such Note on the books of the
Issuers, with full power of substitution in the premises.

Date:


NOTICE:     The signature of this assignment must correspond with the name as
            written upon the face of the within Notes in every particular
            without alteration or enlargement or any change whatsoever.


                                       56

         [FORM OF 8.625% BROADBAND EXCHANGE NOTES DUE DECEMBER 1, 2031]

                 PERMANENT GLOBAL REGISTERED FIXED RATE SECURITY

      THIS NOTE IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE THEREOF. UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR NOTES
IN CERTIFICATED FORM, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC") TO A NOMINEE OF DTC OR
BY DTC OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC TO AT&T CORP. AND AT&T BROADBAND CORP. OR ITS AGENTS FOR
REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY NOTE ISSUED IS REGISTERED
IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS 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.

                                   AT&T CORP.

                              AT&T BROADBAND CORP.

              8.625% Broadband Exchange Notes Due December 1, 2031

REGISTERED [        ]                           CUSIP No. [         ]

      AT&T Corp., a New York corporation ("AT&T") and AT&T Broadband Corp., a
Delaware corporation ("BROADBAND," and with AT&T, each an "ISSUER" and
collectively, the "Issuers"), for value received, hereby jointly and severally
promise to pay to CEDE & CO. or registered assigns the principal sum of [      ]
on December 1, 2031, and to pay interest semiannually on June 1 and December 1,
commencing [      ], on said principal sum at the rate per annum specified in
the title of these Notes, from [      ] until the principal thereof is paid or
made available for payment.

      For purposes of this Note, "Company" within the meaning of the Indenture
referred to herein shall mean each Issuer.

      Reference is hereby made to the further provisions of this global security
(the "GLOBAL SECURITY") set forth on the reverse hereof, which further
provisions shall for all purposes have the same effect as if set forth in this
place.

      This Global Security shall not be valid or become obligatory for any
purpose until the certificate of authentication hereon shall have been executed
by the Trustee under the Indenture referred to herein.


                                       57

      IN WITNESS WHEREOF, each Issuer has caused this Global Security to be duly
executed under its corporate seal.

Dated:  [        ], 2002

                                   AT&T Corp.


                                   By: __________________________________
                                       Name:
                                       Title:

                                   Attest:


                                   By: __________________________________
                                       Name:
                                       Title:


                                   AT&T Broadband Corp.


                                   By: __________________________________
                                       Name:
                                       Title:

                                   Attest:


                                   By: __________________________________
                                       Name:
                                       Title:

TRUSTEE'S CERTIFICATE OF
AUTHENTICATION

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

THE BANK OF NEW YORK,
  As Trustee

By: _______________________________
      Authorized Signatory


                                       58

                                REVERSE OF NOTES

      The Issuers, jointly and severally, agree to pay the principal of,
premium, if any, and interest on, this Global Security in immediately available
funds at the office or agency of the Trustee maintained for that purpose in the
Borough of Manhattan, The City of New York, State of New York, in such coin or
currency of the United States of America as at the time of payment shall be
legal tender for payment of public and private debts; provided, however, that at
the option of the Issuers payment of interest on any Notes issued in definitive
form other than interest due at the Maturity Date shown above may be made by
check mailed to the address of the person entitled thereto as such address shall
appear in the Note register. Interest will be paid to persons in whose names the
Notes are registered at the close of business on the May 15 or November 15, as
the case may be, prior to any interest payment date. Except as otherwise set
forth in the Indenture, Notes in definitive form will not be issued.

      This Note is one of a duly authorized issue of securities of the Issuers,
issued and to be issued under and pursuant to an indenture, dated as of
September 7, 1990, between AT&T and The Bank of New York, as Trustee under
Indenture (herein referred to as the "TRUSTEE"), as amended by the First
Supplemental Indenture, dated as of October 30, 1992, between AT&T and the
Trustee, the Second Supplemental Indenture, dated as of [      ], 2002, between
AT&T and the Trustee, and the Third Supplemental Indenture, dated as of [
], 2002, among the Issuers and the Trustee (herein referred to as the
"INDENTURE"), duly executed and delivered by the Issuers to the Trustee, to
which Indenture and all indentures supplemental thereto reference is hereby made
for description of the rights, limitations of rights, obligations, duties and
immunities thereunder of the Trustee, the Issuers and the Holder (the words
"HOLDERS" or "HOLDER" meaning the registered holders or registered holder) of
these Notes. To the extent the terms of the Indenture and this Note are
inconsistent, the terms of the Indenture shall govern.

      In case an Event of Default with respect to the Notes, as defined in the
Indenture, shall have occurred and be continuing, the principal hereof may be
declared, and upon such declaration shall become due and payable in the manner,
with the effect and subject to the conditions provided in the Indenture.

      The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Issuers and the rights of the Holders of the Notes to be affected under the
Indenture at any time by the Issuers and the Trustee with the consent of the
Holders of a majority in principal amount of the outstanding Notes. The
Indenture also contains provisions permitting the Holders of not less than a
majority in principal amount of the outstanding Notes, on behalf of the Holders
of all Notes, to waive compliance by the Issuers with certain provisions of the
Indenture. The Indenture also provides that the Holders of not less than a
majority in principal amount of the outstanding Notes may waive certain past
defaults and their consequences on behalf of the Holders of all Notes. Any such
consent or waiver by the Holder of any Note shall be conclusive and binding upon
such Holder and upon all future Holders of such Note and of any Note issued upon
registration of transfer hereof or in exchange herefor or in lieu hereof whether
or not notation of such consent or waiver is made upon such Note.

      The Indenture also provides that the Covered Transactions (as defined in
the Indenture), individually or together, (a) will not result in a
consolidation, merger, sale, conveyance or other transfer of property of


                                       59

any Issuer (including stock of subsidiaries) as an entirety or substantially as
an entirety for purposes of Section 5.01 of the Indenture or any other provision
of the Indenture or these Notes, and (b) will not violate Sections 5.01, 5.02 or
5.03 of the Indenture or any other provision of the Indenture or these Notes,
regardless of whether any person assumes any of the indebtedness outstanding
under the Indenture or any other obligation under the Indenture or these Notes.

      The Indenture contains provisions setting forth certain conditions to the
institution of proceedings by Holders of Notes with respect to the Indenture or
for any remedy under the Indenture.

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

      The Notes are issuable as registered Notes without coupons in
denominations of U.S. $1,000 or any amount in excess thereof which is a multiple
of U.S. $1,000 at the office or agency of the Trustee referred to above and in
the manner and subject to the limitations provided in the Indenture. Notes may
be exchanged without service charge for like aggregate principal amount of
Notes.

      At the Effective Time (as defined in the Merger Agreement), each $1,000
principal amount of Notes shall be mandatorily exchanged (the "MANDATORY
EXCHANGE") for $[      ] principal amount of [      ]% Notes Due [      ], 2022
("NEW BROADBAND NOTES").

      New Broadband Notes shall only be issued in denominations of $1,000 and
multiples of $1,000. If the Mandatory Exchange would result in a Holder being
entitled to receive a fractional interest in the New Broadband Notes, the
principal amount such Holder shall receive shall be rounded down to the nearest
$1,000 multiple and such Holder shall receive cash in lieu of a fractional New
Broadband Note for the balance.

      Interest accrued and unpaid on the Notes shall be paid on the date of the
Mandatory Exchange.

      Each Holder of the Notes is deemed, by virtue of having acquired such
Notes, to have expressly and irrevocably consented to the Mandatory Exchange.

      "MERGER AGREEMENT" means the Agreement and Plan of Merger by and among the
Issuers, Comcast Corporation, AT&T Broadband Acquisition Corp., Comcast
Acquisition Corp. and AT&T Comcast Corporation dated as of December 19, 2001, as
it may be amended, supplemented or otherwise modified from time to time, whether
prior to or after the date hereof.

      "BROADBAND INDENTURE" shall refer to the indenture dated as of [ ], 2002,
among Broadband, as issuer, the Cable Guarantors party thereto and The Bank of
New York, as trustee, pursuant to which the New Broadband Notes will be issued
in exchange for the Notes.

      Upon completion of the Mandatory Exchange with respect to Notes and
payment in full of all interest payable pursuant to the eleventh paragraph of
this reverse of this Note, the Issuers


                                       60

shall be fully and completely discharged and released from their obligations
under the Indenture and the Notes with respect to the Notes, including their
obligations for the payment of principal and interest on the Notes.

      If the Merger Agreement is terminated and the Mergers (as defined therein)
are abandoned at any time prior to the Effective Time, (a) Broadband shall be
fully and completely released from its obligations under the Indenture and the
Notes with respect to the Notes, including its obligations for the payment of
principal and interest on the Notes, and (b) the Notes shall cease to be
exchangeable for the New Broadband Notes.

      The Notes may be redeemed, at the option of the Issuers, as a whole or
from time to time in part, on or after December 1, 2001 and prior to maturity,
upon the notice referred to below, at the following redemption prices (expressed
in percentages of the principal amount) during the 12 month periods beginning
December 1:


                                        
            2001......................     105.56%
            2002......................     105.28%
            2003......................     105.00%
            2004......................     104.73%
            2005......................     104.45%
            2006......................     104.17%
            2007......................     103.89%
            2008......................     103.61%
            2009......................     103.34%
            2010......................     103.06%
            2011......................     102.78%
            2012......................     102.50%
            2013......................     102.22%
            2014......................     101.95%
            2015......................     101.67%
            2016......................     101.39%
            2017......................     101.11%
            2018......................     100.83%
            2019......................     100.56%
            2020......................     100.28%


and thereafter at 100%, together in each case with accrued interest to the date
fixed for redemption. As provided in the Indenture, notice of redemption to the
holders of Notes to be redeemed as a whole or in part shall be given by mailing
a notice of such redemption not less than thirty nor more than sixty days prior
to the date fixed for redemption to their last addresses as they shall appear
upon the register kept for that purpose.

      Upon due presentment for registration of transfer of this Note at the
above-mentioned office or agency of the Trustee, a new Global Security or Notes
of authorized denominations, for a like aggregate principal amount will be
issued to the transferee as provided in the Indenture. No service charge shall
be made for any such transfer, but the Issuers may require payment of a


                                       61

sum sufficient to cover any tax or other governmental charge that may be imposed
in relation thereto.

      The Issuers, the Trustee, and any agent of the either Issuer or the
Trustee may deem and treat the Holder hereof as the absolute owner hereof
(whether or not this Global Security shall be overdue and notwithstanding any
notation of ownership or other writing hereon) for the purpose of receiving
payment of or on account of the principal hereof and subject to the provisions
above, of premium or interest thereon, and for all other purposes and neither
the Issuers nor the Trustee nor any such agent shall be affected by any notice
to the contrary.

      No recourse shall be had for the payment of the principal of, premium, if
any, or the interest on, this Global Security or for any claim based hereon, or
otherwise in respect hereof, or based on or in respect of the Indenture or any
indenture supplemental thereto, against any incorporator, shareholder, officer
or director as such, past, present or future, of the Issuers or of any successor
corporation, either directly or through the Issuers or of any successor
corporation whether by virtue of any constitution, statute or rule of law or by
the enforcement of any assessment or penalty or otherwise, all such liability
being, by the acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

      This Global Security shall be deemed to be a contract made under the laws
of the State of New York and for all purposes shall be governed by and construed
in accordance with the laws of said State.

      Unless otherwise defined in this Global Security, all terms used in this
Global Security which are defined in the Indenture shall have the meanings
assigned to them in the Indenture.


                                       62

                                  ABBREVIATIONS

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

      TEN COM  - as tenants in common

      TEN ENT  - as tenants by the entireties

      JT TEN   - as joint tenants with right of survivorship and not as tenants
                 in common

      UNIF GIFT MIN ACT - ________________(Cust)___________(Minor)

      Under Uniform Gifts to Minor Act ________________(State)

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

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

[PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE]

_________________________________________________________________________

[PLEASE PRINT OR TYPE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE]

_________________________________________________________________________

the within Notes and all rights thereunder, hereby irrevocably constituting and
appointing such person attorney to transfer such Note on the books of the
Issuers, with full power of substitution in the premises.

Date:


NOTICE:     The signature of this assignment must correspond with the name as
            written upon the face of the within Notes in every particular
            without alteration or enlargement or any change whatsoever.



                                       63