Document:

<PAGE>

                              MEDIAONE GROUP, INC.,
                                     Issuer,

                                   AT&T CORP.,
                                   Guarantor,

                                       and

                           BANK ONE TRUST COMPANY, NA,
                (successor to The First National Bank of Chicago)
                                     Trustee

                          FIFTH SUPPLEMENTAL INDENTURE
                           Dated as of August 10, 2000

             Supplemental to Indenture dated as of November 13, 1995

<PAGE>

     FIFTH SUPPLEMENTAL INDENTURE, dated as of August 10, 2000 (this
"Supplemental Indenture"), made and entered into by and among MediaOne Group,
Inc., a corporation organized and existing under the laws of the State of
Delaware having its principal office at 188 Inverness Drive West, Englewood, CO
80112 (the "Company"), AT&T Corp., a corporation organized and existing under
the laws of the State of New York having its principal office at 32 Avenue of
Americas, New York, NY 10013-2412 (the "AT&T") and Bank One Trust Company, NA, a
national banking association duly organized and existing under the laws of the
United States, as Trustee (the "Trustee") under the indenture of the Company
(the "Indenture") dated as of November 13, 1995.

     WHEREAS, Section 9.01(6) of the Indenture provides that the Company and
Trustee may enter into one or more indentures supplemental to the Indenture
without the consent of any Securityholder to make any change in the Indenture
that does not adversely affect the rights of any Securityholder in any material
respect; and

     WHEREAS Bank One Trust Company, NA has succeeded The First National Bank of
Chicago as Trustee under the Indenture pursuant to the transfer of substantially
all of the corporate trust business of The First National Bank of Chicago to
Bank One Trust Company, NA; and

     WHEREAS, the entry into this Supplemental Indenture by the parties hereto
is in all respects authorized by the provisions of the Indenture; and

     WHEREAS, the Company has duly authorized the execution and delivery of this
Supplemental Indenture, and all things necessary have been done to make this
Supplemental Indenture a valid agreement of the Company; and

     WHEREAS, the Guarantor has duly authorized the execution and delivery of
this Supplemental Indenture, and all things necessary have been done to make
this Supplemental Indenture a valid agreement of the Guarantor;

     NOW, THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the
Company, the Guarantor and the Trustee mutually covenant and agree for the equal
and ratable benefit of the Holders of the Securities as follows:

                                    ARTICLE I
                    Certain Provisions of General Application

     SECTION 1.1. DEFINITIONS.

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

     (1)  the terms defined in this Article have the meanings assigned to them
in this Article;
<PAGE>

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

     (3)  capitalized terms used but not defined herein and in the Recitals are
used as they are defined in the Indenture.

     "Capital Stock" means (i) in the case of a corporation, corporate stock,
(ii) in the case of an association or business entity, any and all shares,
interests, participations, rights or other equivalents (however designated) of
corporate stock, (iii) in the case of a partnership or limited liability
company, partnership or membership interests (whether general or limited) and
(iv) any other interest or participation that confers on a Person the right to
receive a share of the profits and losses of, or distributions of assets of, the
issuing Person.

     "Guarantee" means any guarantee of the obligations of the Company in
respect of the PIES Securities under the Indenture and the PIES Securities by
any Person in accordance with the provisions of the Indenture. When used as a
verb, "Guarantee" shall have a corresponding meaning.

     "Guarantor" means any Person that incurs a Guarantee; PROVIDED that upon
the termination of the obligations of such Person in accordance with the
Indenture, such Person shall cease to be a Guarantor.

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

     "PIES Securities" means the 6 1/4% Exchangeable Notes due August 15, 2001,
representing Premium Income Exchangeable Securities and the 7.00% Exchangeable
Notes due November 15, 2002, representing Premium Income Exchangeable Securities

     SECTION 1.2. EFFECT OF HEADINGS.

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

     SECTION 1.3. SUCCESSORS AND ASSIGNS.

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

     SECTION 1.4. SEPARABILITY.

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

     SECTION 1.5. CONFLICT WITH TRUST INDENTURE ACT.

                                       3
<PAGE>

     If any provision hereof limits, qualifies or conflicts with another
provision hereof which is required to be included in this Supplemental Indenture
by any of the provisions of the Trust Indenture Act, such required provision
shall control.

     SECTION 1.6. BENEFITS OF SUPPLEMENTAL INDENTURE.

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

     SECTION 1.7. GOVERNING LAW.

     THIS SUPPLEMENTAL INDENTURE SHALL BE DEEMED TO BE A CONTRACT MADE UNDER THE
LAWS OF THE STATE OF NEW YORK AND THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED
BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

                                   ARTICLE II
                              SUCCESSOR CORPORATION

     Section 5.01 of the Indenture is amended in its entirety to read as
follows:

     "SECTION 5.01. WHEN THE COMPANY AND GUARANTOR MAY MERGE, ETC.

     The Company and the Guarantor may consolidate with, or merge into, or be
merged into, or transfer or lease its properties and assets substantially as an
entirety to, any Person provided (i) that the Person is a corporation which
assumes by supplemental indenture all the obligations of the Company and the
Guarantor, as the case may be, under the Securities and any coupons appertaining
thereto and under this Indenture; and (ii) that after giving effect thereto, no
Default or Event of Default shall have occurred and be continuing. Thereafter,
all such obligations of the Company or the Guarantor, as the case may be, shall
terminate."

                                   ARTICLE III
                                    GUARANTEE

     The Indenture is amended to include the following Article 10A after Article
10 thereof:

                                  "ARTICLE 10A
                                    GUARANTEE

     SECTION 10A.1. GUARANTEE.

     The Guarantor hereby unconditionally and irrevocably guarantees, as a
primary obligor and not merely as a surety, to each Holder and to the Trustee
and its successors and assigns (a) the full and punctual payment of principal of
and interest on the PIES Securities, when due, whether on maturity, by
acceleration, by redemption or otherwise, and all other

                                       4
<PAGE>

monetary obligations of the Company in respect of the PIES Securities under this
Indenture (including obligations to the Trustee) and the PIES Securities and (b)
the full and punctual performance within applicable grace periods of all other
obligations of the Company in respect of the PIES Securities whether for
expenses, indemnification or otherwise under this Indenture and the PIES
Securities (all the foregoing being hereinafter collectively called the
"Guaranteed Obligations"). The Guarantor further agrees that the Guaranteed
Obligations may be extended or renewed, in whole or in part, without notice or
further assent from the Guarantor, and that the Guarantor shall remain bound
under this Article 10A notwithstanding any extension or renewal of any
Guaranteed Obligation.

     The Guarantor waives presentation to, demand of, payment from and protest
to the Company of any of the Guaranteed Obligations and also waives notice of
protest for nonpayment. The Guarantor waives notice of any default under the
PIES Securities or the Guaranteed Obligations. The obligations of the Guarantor
hereunder shall not be affected by (a) the failure of any Holder or the Trustee
to assert any claim or demand or to enforce any right or remedy against the
Company or any other Person under this Indenture, the PIES Securities or any
other agreement or otherwise; (b) any extension or renewal of any thereof; (c)
any rescission, waiver, amendment or modification of any of the terms or
provisions of this Indenture, the PIES Securities or any other agreement
relating to this Indenture or the PIES Securities; (d) the release of any
security held by any Holder or the Trustee for the Guaranteed Obligations or any
of them; (e) the failure of any Holder or the Trustee to exercise any right or
remedy against any other guarantor of the Guaranteed Obligations; or (f) any
change in the ownership of the Guarantor, except as provided in Section 5.01.

     The Guarantor hereby waives any right to which it may be entitled to have
the assets of the Company first be used and depleted as payment of the Company's
or the Guarantor's obligations hereunder prior to any amounts being claimed from
or paid by the Guarantor hereunder. The Guarantor hereby waives any right to
which it may be entitled to require that the Company be sued prior to an action
being initiated against the Guarantor.

     The Guarantor further agrees that its Guarantee herein constitutes a
guarantee of payment, performance and compliance when due (and not a guarantee
of collection) and waives any right to require that any resort be had by any
Holder or the Trustee to any security held for payment of the Guaranteed
Obligations.

     Except as expressly set forth in Sections 5.01 and 10A.2, the obligations
of the Guarantor hereunder shall not be subject to any reduction, limitation,
impairment or termination for any reason, including any claim of waiver,
release, surrender, alteration or compromise, and shall not be subject to any
defense of setoff, counterclaim, recoupment or termination whatsoever or by
reason of the invalidity, illegality or unenforceability of the Guaranteed
Obligations or otherwise. Without limiting the generality of the foregoing, the
obligations of the Guarantor herein shall not be discharged or impaired or
otherwise affected by the failure of any Holder or the Trustee to assert any
claim or demand or to enforce any remedy under this Indenture, the PIES
Securities or any other agreement relating to this Indenture or the PIES
Securities, by any waiver or modification of any thereof, by any default,
failure or delay, willful or otherwise, in the performance of the obligations,
or by any other act or thing or omission or delay to do any other act or thing
which may or might in any manner or to any extent vary the

                                       5
<PAGE>

risk of the Guarantor or would otherwise operate as a discharge of the Guarantor
as a matter of law or equity.

     The Guarantor agrees that its Guarantee shall remain in full force and
effect until payment in full of all the Guaranteed Obligations. The Guarantor
further agrees that its Guarantee herein shall continue to be effective or be
reinstated, as the case may be, if at any time payment, or any part thereof, of
principal of or interest on any Guaranteed Obligation is rescinded or must
otherwise be restored by any Holder or the Trustee upon the bankruptcy or
reorganization of the Company or otherwise.

     In furtherance of the foregoing and not in limitation of any other right
which any Holder or the Trustee has at law or in equity against the Guarantor by
virtue hereof, upon the failure of the Company to pay the principal of or
interest on any Guaranteed Obligation when and as the same shall become due,
whether at maturity, by acceleration, by redemption or otherwise, or to perform
or comply with any other Guaranteed Obligation, the Guarantor hereby promises to
and shall, upon receipt of written demand by the Trustee, forthwith pay, or
cause to be paid, in cash, to the Holders or the Trustee an amount equal to the
sum of (i) the unpaid principal amount of such Guaranteed Obligations, (ii)
accrued and unpaid interest on such Guaranteed Obligations (but only to the
extent not prohibited by law) and (iii) all other monetary obligations of the
Company to the Holders and the Trustee.

     The Guarantor agrees that it shall not be entitled to any right of
subrogation in relation to the Holders in respect of any Guaranteed Obligations
guaranteed hereby until payment in full of all Guaranteed Obligations. The
Guarantor further agrees that, as between it, on the one hand, and the Holders
and the Trustee, on the other hand, (x) the maturity of the Guaranteed
Obligations guaranteed hereby may be accelerated as provided in Article 6 of
this Indenture for the purposes of any Guarantee herein, notwithstanding any
stay, injunction or other prohibition preventing such acceleration in respect of
the Guaranteed Obligations guaranteed hereby, and (y) in the event of any
declaration of acceleration of such Guaranteed Obligations as provided in such
Article 6, such Guaranteed Obligations (whether or not due and payable) shall
forthwith become due and payable by the Guarantor for purposes of this Section
10A.1.

     The Guarantor also agrees to pay any and all costs and expenses (including
reasonable attorneys' fees and expenses) incurred by the Trustee or any Holder
in enforcing any rights under this Section 10A.1.

     SECTION 10A.2. LIMITATION ON LIABILITY.

     Any term or provision of this Indenture to the contrary notwithstanding,
the maximum, aggregate amount of the Guaranteed Obligations guaranteed hereunder
by the Guarantor shall not exceed the maximum amount that can be hereby
guaranteed without rendering this Indenture, as it relates to the Guarantor,
voidable under applicable law relating to fraudulent conveyance or fraudulent
transfer or similar laws affecting the rights of creditors generally.

     SECTION 10A.3. NO WAIVER.

                                       6
<PAGE>

     Neither a failure nor a delay on the part of either the Trustee or the
Holders in exercising any right, power or privilege under this Article 10A shall
operate as a waiver thereof, nor shall a single or partial exercise thereof
preclude any other or further exercise of any right, power or privilege. The
rights, remedies and benefits of the Trustee and the Holders herein expressly
specified are cumulative and not exclusive of any other rights, remedies or
benefits which either may have under this Article 10A at law, in equity, by
statute or otherwise.

     SECTION 10A.4. MODIFICATION.

     No modification, amendment or waiver or any provision of this Article 10A,
nor the consent to any departure by the Guarantor therefrom, shall in any event
be effective unless the same shall be in writing and signed by the Trustee, and
then such waiver or consent shall be effective only in the specific instance and
for the purpose for which given. No notice to or demand on any Guarantor in any
case shall entitle such Guarantor to any other or further notice or demand in
the same, similar or other circumstances."

                                   ARTICLE IV
                             AGREEMENT TO GUARANTEE

     SECTION 4.1. AGREEMENT TO GUARANTEE.

     AT&T hereby agrees to unconditionally guarantee the Company's obligations
under the PIES Securities on the terms and subject to the conditions set forth
in Article 10A of the Indenture and to be bound by all other applicable
provisions of the Indenture and the PIES Securities.

                                    ARTICLE V
                                  MISCELLANEOUS

     SECTION 5.1. CONFIRMATION OF INDENTURE.

     The Indenture, as supplemented and amended by this Supplemental Indenture
and all other indentures supplemental thereto, is in all respects ratified and
confirmed, and the Indenture, this Supplemental Indenture and all indentures
supplemental thereto shall be read, taken and construed as one and the same
instrument.

     SECTION 5.2. CONCERNING THE TRUSTEE.

     The Trustee assumes no duties, responsibilities or liabilities by reason of
this Supplemental Indenture other than as set forth in the Indenture.

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

     This Supplemental Indenture may be executed in any number of counterparts,
each of which shall be an original; but such counterparts shall together
constitute but one and the same instrument.

                                       7
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed, and their respective corporate seals to be
hereunto affixed and attested, all as of the day and year first above written.

                                       MEDIAONE GROUP, INC.

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

Attest:
       ------------------------------
       Name:
       Title:

                                       AT&T CORP.

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

Attest:
       ------------------------------
       Name:
       Title:

                                       BANK ONE TRUST COMPANY, NA,
                                          as Trustee

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

Attest:
       ------------------------------
       Name:
       Title:

                                       8
<PAGE>

STATE OF         )
                 )       SS:
COUNTY OF        )

     On the   day of ___________, 2000, before me personally came___________
__________________________, to me known, who, being by me duly sworn, did
depose and say that she/he is the ______________________ of MEDIAONE GROUP,
INC., one of the corporations described in and which executed the foregoing
instrument; that she/he knows the seal of said corporation; that the seal
affixed to said instrument is such corporate seal; that it was so affixed by
authority of the Board of Directors of said corporation, and that she/he
signed her/his name thereto by like authority.

                                       -----------------------------------
                                                   Notary Public

SEAL

STATE OF         )
                 )         SS:
COUNTY OF        )

     On the   day of ___________, 2000, before me personally came___________
__________________________, to me known, who, being by me duly sworn, did
depose and say that she/he is the ______________________ of Bank One Trust
Company, NA, one of the corporations described in and which executed the
foregoing instrument; that she/he knows the seal of said corporation; that
the seal affixed to said instrument is such corporate seal; that it was so
affixed by authority of the Board of Directors of said corporation, and that
she/he signed her/his name thereto by like authority.

                                       -----------------------------------
                                                   Notary Public

SEAL<PAGE>

                              MEDIAONE GROUP, INC.

                                       and

            WELLS FARGO BANK MINNESOTA, NATIONAL ASSOCIATION, Trustee

                         SEVENTH SUPPLEMENTAL INDENTURE
                           Dated as of August 10, 2000

              Supplement to Indenture Dated as of September 6, 1995
                               as supplemented by
           First Supplemental Indenture Dated as of September 6, 1995,
           Second Supplemental Indenture Dated as of November 1, 1995,
           Third Supplemental Indenture Dated as of October 24, 1996,
            Fourth Supplemental Indenture Dated as of June 10, 1998
           Fifth Supplemental Indenture Dated as of June 12, 1998, and
             Sixth Supplemental Indenture Dated as of June 15, 2000

              7.96% Subordinated Deferrable Interest Notes due 2025
              8.25% Subordinated Deferrable Interest Notes due 2036

                                       1
<PAGE>

     SIXTH SUPPLEMENTAL INDENTURE, dated as of August 10, 2000 (this
"Supplemental Indenture"), is entered into by and among MediaOne Group, Inc., a
Delaware corporation (the "Company"), AT&T Corp., a New York corporation (the
"Guarantor"), and Wells Fargo Bank Minnesota, National Association, as trustee
(the "Trustee").

     WHEREAS the Company is a party to the Indenture, dated as of September 6,
1995, as supplemented by a First Supplemental Indenture, dated as of September
6, 1995, a Second Supplemental Indenture, dated as of November 1, 1995, a Third
Supplemental Indenture, dated as of October 24, 1996, a Fourth Supplemental
Indenture, dated as of June 10, 1998, and a Fifth Supplemental Indenture dated
as of June __, 2000 (collectively, the "Original Indenture", and together with
this Supplemental Indenture, the "Indenture"), pursuant to which U S WEST
Capital Funding, Inc. ("Funding") issued, and the Trustee authenticated and
delivered the following securities:

(a)  $618,556,725 aggregate principal amount (of which $51,379,475 aggregate
     liquidation amount remains outstanding) of Funding's 7.96% Subordinated
     Deferrable Interest Notes due 2025 (the "Trust A Notes"); and

(b)  $494,845,375 aggregate principal amount (of which $44,485,825 aggregate
     liquidation amount remains outstanding) of Funding's 8.25% Subordinated
     Deferrable Interest Notes due 2036 (the "Trust B Notes," and together with
     the Trust A Notes, the "Subject Securities");

     WHEREAS MediaOne Financing Trust A, a Delaware statutory business trust
("Trust A"), has issued $600,000,000 aggregate liquidation amount of its 7.96%
Trust Originated Preferred Securities (of which $32,822,750 aggregate
liquidation amount remains outstanding), representing undivided beneficial
interests in the assets of Trust A, and has invested the proceeds from such
issuance in the Trust A Notes;

     WHEREAS MediaOne Financing Trust B, a Delaware statutory business trust
("Trust B"), has issued $480,000,000 aggregate liquidation amount of its 8.25%
Trust Preferred Securities (of which $29,640,450 aggregate liquidation amount
remains outstanding), representing undivided beneficial interests in the assets
of Trust B, and has invested the proceeds from such issuance in the Trust B
Notes;

     WHEREAS, in connection with the separation of MediaOne Group, Inc.
("MediaOne Group") from U S WEST, Inc. in June 1998, MediaOne Group directly
assumed U S WEST Capital Funding, Inc.'s obligations with respect to the Subject
Securities;

     WHEREAS MediaOne Group merged with and into the Company on June 15, 2000;

     WHEREAS the Guarantor desires to irrevocably and unconditionally guarantee,
on a subordinated basis, the full and punctual payment of principal of and
interest on the Subject Securities when due, whether at maturity, by
acceleration, by redemption or otherwise, and all other monetary obligations of
the Company under the Subject Securities and, with respect to the Subject
Securities, under the Indenture (including obligations of the Company to the
Trustee),

                                       2
<PAGE>

and the full and punctual performance (within applicable grace periods) of all
other obligations of the Company under the Subject Securities and, with respect
to the Subject Securities, under the Indenture;

     WHEREAS the Company and the Guarantor have requested that the Trustee
execute and deliver this Supplemental Indenture and all requirements necessary
to make this Supplemental Indenture a valid instrument in accordance with its
terms and to make the guarantee provided for herein the valid obligation of the
Guarantor, and the execution and delivery of this Supplemental Indenture have
been duly authorized in all respects;

     NOW, THEREFORE, in consideration of the mutual promises contained herein
and for other good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the Company, the Guarantor and the Trustee hereby
agree as follows for the equal and ratable benefit of the Holders of the Subject
Securities:

     SECTION 1. DEFINITIONS.

     (a)  Capitalized terms used herein but not defined herein have the meanings
ascribed to such terms in the Original Indenture.

     (b)  Article I, Section 1.01, of the Original Indenture is hereby
supplemented, solely with respect to this Supplemental Indenture, to add the
following definitions:

          "Guarantor Senior Indebtedness" means all indebtedness, obligations or
     liabilities of the Guarantor, whether outstanding at the date of
     effectiveness of the Fifth Supplemental Indenture to the Indenture or
     thereafter incurred, assumed, guaranteed or otherwise created (including,
     without limitation, interest accruing on or after a bankruptcy or other
     similar event, whether or not an allowed claim therein), in respect of (A)
     indebtedness of the Guarantor for money borrowed, (B) indebtedness
     evidenced by securities, debentures, bonds, notes or other similar
     instruments issued by the Guarantor, (C) all capital lease obligations of
     the Guarantor, (D) all obligations of the Guarantor issued or assumed as
     the deferred purchase price of property, all conditional sale obligations
     of the Guarantor and all obligations of such obligor under any title
     retention agreement (but excluding trade accounts payable arising in the
     ordinary course of business), (E) all obligations of the Guarantor for
     reimbursement on any letter of credit, banker's acceptance, security
     purchase facility or similar credit transaction, (F) all obligations of the
     type referred to in clauses (A) through (E) of other Persons for the
     payment of which the Guarantor is responsible or liable as obligor,
     guarantor or otherwise, and (G) all obligations of the type referred to in
     clauses (A) through (F) of other Persons secured by any lien on any
     property or asset of the Guarantor (whether or not such obligation is
     assumed by such obligor), except for any such indebtedness, obligations or
     liabilities the terms of which expressly provide that such indebtedness,
     obligation or liability is equal or subordinated in right of payment to the
     Guarantor's guarantee with respect to the Subject Securities, as the case
     may be. For greater certainty, "Guarantor Senior Indebtedness" includes all
     indebtedness, obligations or liabilities between or among the Guarantor and
     its Affiliates, except for such indebtedness,

                                       3
<PAGE>

     obligations or liabilities the terms of which expressly provide that such
     indebtedness, obligation or liability is equal or subordinated in right of
     payment to the Guarantor's guarantee with respect to the Subject
     Securities, as the case may be.

          "Guarantor Senior Indebtedness Representative" means any Person whom
     the Guarantor has, by written notice to the Trustee, identified as the
     indenture trustee or other trustee, agent or representative for an issue of
     Guarantor Senior Indebtedness.

     SECTION 2. GUARANTEE.

     (a)  The Guarantor irrevocably and unconditionally guarantees, on a
subordinated basis as set forth herein (the "Guarantee"), to each Holder of
Subject Securities and to the Trustee and its successors and assigns, (i) the
full and punctual payment of principal of and interest on the Subject Securities
when due, whether at maturity, by acceleration, by redemption or otherwise, and
all other monetary obligations of the Company with respect to the Subject
Securities under the Indenture (including obligations of the Company to the
Trustee) and the Subject Securities and (ii) the full and punctual performance
(within applicable grace periods) of all other obligations of the Company with
respect to the Subject Securities under the Indenture and the Subject
Securities.

     (b)  The Guarantor further agrees that the Guarantee constitutes a
guarantee of payment and performance and not of collection.

     (c)  The obligations of the Guarantor to make any payment hereunder may be
satisfied by causing the Company to make such payment.

     (d)  The Guarantor also agrees to pay any and all costs and expenses
(including reasonable attorneys fees) incurred by the Trustee or any Holder of
Subject Securities in enforcing any of their respective rights under the
Guarantee.

     SECTION 3. SUBORDINATION.

     The Guarantee is hereby expressly subordinated in right of payment, to the
extent and in the manner provided in this Supplemental Indenture, to the prior
payment in full in cash or cash equivalents of all Guarantor Senior Indebtedness
and such subordination is for the benefit of the holders of Guarantor Senior
Indebtedness. Upon any payment or distribution of all or substantially all the
assets of the Guarantor, whether voluntary or involuntary, or upon any
reorganization, readjustment, arrangement or similar proceeding relating to the
Guarantor or its property, whether or not the Guarantor is a party thereto and
whether in bankruptcy, insolvency, receivership or similar proceedings, or upon
any assignment by the Guarantor for the benefit of creditors or upon any other
marshaling of the assets and liabilities of the Guarantor:

          (i)  all Guarantor Senior Indebtedness shall first be paid in full in
     cash or cash equivalents, or provisions made for such payment by deposit
     thereof in trust with a bank or banks (either theretofore acting as
     trustees under indentures pursuant to which Guarantor Senior Indebtedness
     shall have been issued or duly appointed paying agents for

                                       4
<PAGE>

     the purpose), before any payment is made in respect of the Guarantee;

          (ii) any payment in respect of the Guarantee to which the Holders of
     Subject Securities would be entitled except for the provisions of this
     Section shall be paid or delivered by the Guarantor or the liquidating
     trustee or agent or other Person making such payment, whether a trustee in
     bankruptcy, a receiver or liquidating trustee or other trustee or agent,
     directly and ratably to the holders of Guarantor Senior Indebtedness or the
     Guarantor Senior Indebtedness Representatives, as the case may be (subject
     to any subordination of any class of Guarantor Senior Indebtedness, by the
     provisions thereof, to any other class or classes of Guarantor Senior
     Indebtedness), according to the aggregate amounts remaining unpaid on
     account of the principal of; and the premium, if any, and interest on, and
     other monetary obligation with respect to, the Guarantor Senior
     Indebtedness, to the extent necessary to make payment in full of all
     Guarantor Senior Indebtedness remaining unpaid, after giving effect to any
     concurrent payment or distribution, or provision therefor, to the holders
     of such Guarantor Senior Indebtedness; and

          (iii) in the event that, notwithstanding the foregoing, any payment of
     any kind or character in respect of the Guarantee shall be received by the
     Trustee or the Holders of Subject Securities before all Guarantor Senior
     Indebtedness is paid in full, or provision made as aforesaid for its
     payment, such payment shall be held in trust for the ratable benefit of and
     shall be ratably paid over or delivered to the holders of Guarantor Senior
     Indebtedness remaining unpaid or unprovided for or the Guarantor Senior
     Indebtedness Representatives, as provided in the foregoing subparagraph
     (ii), for application to the payment of all principal of, and premium, if
     any, and interest on, and other monetary obligation with respect to, such
     Guarantor Senior Indebtedness remaining unpaid until all such Guarantor
     Senior Indebtedness shall have been paid in full, after giving effect to
     any concurrent payment or distribution, or provision therefor, to the
     holders of such Guarantor Senior Indebtedness.

     SECTION 4. DEFAULT ON GUARANTOR SENIOR INDEBTEDNESS.

     Subject to the provisions of Section 5, in the event and during the
continuation of any default in the payment of principal of, or premium, if any,
or interest on, or other monetary obligation with respect to, any Guarantor
Senior Indebtedness beyond any applicable period of grace, or in the event that
any event of default with respect to any Guarantor Senior Indebtedness shall
have occurred and be continuing, unless and until such default or event of
default shall have been cured or waived or shall have ceased to exist, no
payment shall be made by the Guarantor in respect of the Guarantee. Nothing
contained in this Section or elsewhere in this Supplemental Indenture shall,
however, prevent the application by the Trustee of any moneys deposited with it
hereunder by the Guarantor in respect of the Guarantee, if at the time of such
deposit, the Trustee did not have written notice of any event prohibiting the
making of such deposit by the Guarantor.

     The Guarantor shall give prompt written notice to the Trustee of any facts
that would prohibit the making of any payment of moneys in respect of the
Guarantee, including any dissolution, winding up, liquidation or reorganization
of the Guarantor. Anything in this Section

                                       5
<PAGE>

or elsewhere in this Supplemental Indenture to the contrary notwithstanding, the
Trustee shall not be charged with knowledge of the existence of any Guarantor
Senior Indebtedness or of any default or event of default with respect to any
Guarantor Senior Indebtedness or of any other facts that would prohibit the
making of any payment of moneys hereunder, unless and until the Trustee shall
have received notice in writing to that effect signed by an officer of the
Guarantor or by a holder of Guarantor Senior Indebtedness who shall have been
certified by the Guarantor or otherwise established to the reasonable
satisfaction of the Trustee to be such holder or by a Guarantor Senior
Indebtedness Representative.

     SECTION 5. DISPUTES WITH HOLDERS OF CERTAIN GUARANTOR SENIOR INDEBTEDNESS.

     Any failure by the Guarantor to make any payment on or perform any other
obligation under Guarantor Senior Indebtedness, other than Guarantor Senior
Indebtedness consisting of any indebtedness incurred by the Guarantor or assumed
or guaranteed, directly or indirectly, by the Guarantor for money borrowed (or
any deferral, renewal, extension or refunding thereof) or consisting of any
indebtedness or obligation in which the provisions of this Section shall have
been waived by the Guarantor in the instrument or instruments by which the
Guarantor incurred, assumed, guaranteed or otherwise created such indebtedness
or obligation, shall not be deemed a default or event of default under Section 4
hereof for so long as (a) the Guarantor disputes its obligation to make such
payment or perform such obligation and (b) either (i) such dispute does not
result in a judgment against the Guarantor that remains undischarged, unbonded
or in force for more than the applicable appeal period or (ii) in the event of
such a judgment, the Guarantor in good faith prosecutes an appeal or other
proceeding for review and the Guarantor has obtained a stay of execution from
such judgment pending such appeal or review.

     SECTION 6. WHEN PAYMENT MUST BE PAID OVER

     If a payment is made pursuant to the Guarantee that because of Section 4 or
5 should not have been made to the Holders of the Subject Securities, the
Holders of Subject Securities who receive the payment shall hold it in trust for
holders of Guarantor Senior Indebtedness and pay it over to them as their
interests may appear.

     SECTION 7. RELATIVE RIGHTS.

     This Section defines the relative rights of Holders of Subject Securities
with respect to the Guarantee and holders of Guarantor Senior Indebtedness.
Nothing in this Indenture shall:

     (a)  impair, as between the Guarantor and Holders of Subject
Securities, the obligation of the Guarantor, which is absolute and
unconditional, to make payment under the Guarantee when, as and if due pursuant
to this Supplemental Indenture;

     (b)  affect the relative rights of Holders of Subject Securities and
creditors of the Guarantor other than holders of Guarantor Senior Indebtedness;
or

     (c)  prevent the Trustee or any Holder of Subject Securities from
exercising its available remedies with respect to the Guarantee, subject to the
rights of holders of Guarantor Senior

                                       6
<PAGE>

Indebtedness to receive distributions otherwise payable to Holders of Subject
Securities.

     SECTION 8. SUBORDINATION MAY NOT BE IMPAIRED BY GUARANTOR.

     No right of any holder of Guarantor Senior Indebtedness to enforce the
subordination of the Guarantee shall be impaired by any act or failure to act by
the Guarantor or by its failure to comply with this Supplemental Indenture.

     SECTION 9. SEC REPORTS.

     The Guarantor shall file with the Trustee within 15 days after it files
them with the SEC copies of the annual reports and of the information, documents
and other reports (or copies of such portions of any of the foregoing as the SEC
may by rules and regulations prescribe) which the Guarantor is required to file
with the SEC pursuant to Section 13 or 15(d) of the Securities Exchange Act of
1934.

     SECTION 10. CONFLICT WITH THE TIA.

     If any provision of this Supplemental Indenture modifies or excludes any
provision of the TIA that is required under such Act to be part of and govern
the Indenture, the latter provision of the TIA shall control. If any provision
hereof modifies or excludes any provision of the TIA that may be so modified or
excluded, the latter provision of the TIA shall be deemed to apply to this
Supplemental Indenture, as so modified or excluded, as the case may be.

     SECTION 11. DATE AND TIME OF EFFECTIVENESS.

     This Supplemental Indenture shall become a legally effective and binding
instrument at and as of the date hereof.

     SECTION 12. SUPPLEMENTAL INDENTURE INCORPORATED INTO INDENTURE.

     The terms and conditions of this Supplemental Indenture shall be deemed to
be part of the Indenture for all purposes relating to the Subject Securities.
The Original Indenture, is hereby incorporated by reference herein and the
Original Indenture, as supplemented by this Supplemental Indenture, is in all
respects adopted, ratified and confirmed.

     SECTION 13. SUBJECT SECURITIES DEEMED CONFORMED.

     As of the date hereof, the provisions of the Subject Securities then
outstanding shall be deemed to be conformed, without the necessity for any
reissuance or exchange of such Subject Security or any other action on the part
of the Holders of Subject Securities, the Company or the Trustee, so as to
reflect this Supplemental Indenture.

                                       7
<PAGE>

     SECTION 14. SUCCESSORS.

     All agreements of the Company, the Guarantor and the Trustee in this
Supplemental Indenture and in the Indenture shall bind their respective
successors.

     SECTION 15. BENEFITS OF SUPPLEMENTAL INDENTURE.

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

     SECTION 16. SEPARABILITY.

     In case any provision in this Supplemental Indenture, or in the Indenture,
shall be invalid, illegal or unenforceable, the validity, legality and
enforceability of the remaining provisions shall not in any way be affected or
impaired thereby, it being intended that all of the provisions hereof shall be
enforceable to the full extent permitted by law.

     SECTION 17. HEADINGS.

     The section headings of this Supplemental Indenture have been inserted for
convenience of reference only, are not to be considered a part of this
Supplemental Indenture and shall in no way modify or restrict any of the terms
or provisions hereof.

     SECTION 18. NOTICES.

     All notices provided for herein shall be in writing, duly signed by the
party giving such notice, and shall be delivered, telecopied or mailed by first
class mail as follows:

          (a)  if given to the Guarantor, to the Guarantor's mailing address set
forth below or such other address as the Guarantor may give notice of to the
Holders of the Subject Securities:

                           AT&T Corp.
                           32 Avenue of the Americas
                           New York, New York 10013-2412
                              Attention: Legal Department;

          (b)  if given to the Trustee, to the address Set forth in the
Indenture or to such other address as the Trustee may give notice of to the
Holders of Subject Securities; and

          (c)  if given to any Holder of Subject Securities, at the address set
forth on the books and records of Trust A or Trust B, as applicable.

     All such notices shall be deemed to have been given when received in
person, telecopied

                                       8
<PAGE>

with receipt confirmed, or mailed by first class mail, postage prepaid except
that if a notice or other document is refused delivery or cannot be delivered
because of a changed address of which no notice was given, such notice or other
document shall be deemed to have been delivered on the date of such refusal or
inability to deliver.

     SECTION 19. GOVERNING LAW.

     THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED AND CONSTRUED IN ACCORDANCE
WITH THE INTERNAL LAWS OF THE STATE OF NEW YORK.

     SECTION 20. COUNTERPARTS.

     This Supplemental Indenture may be executed in two or more counterparts,
each of which shall constitute an original, but all of which when taken together
shall constitute the same instrument.

     SECTION 21. TRUSTEE NOT RESPONSIBLE FOR RECITALS.

     The recitals herein contained are made by the Company and the Guarantor,
and not by the Trustee, and the Trustee assumes no responsibility for the
correctness thereof. The Trustee shall not be responsible in any manner
whatsoever for or in respect of the validity or sufficiency of this Supplemental
Indenture.

                                       9
<PAGE>

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

                                       MEDIAONE GROUP, INC.

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

                                       AT&T CORP.

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

                                       WELLS FARGO BANK MINNESOTA,
                                       NATIONAL ASSOCIATION, as Trustee
                                       By:
                                          --------------------------------
                                       Name:
                                       Title:

                                       10

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}]]