Document:

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                                                                     EXHIBIT 4.1

                      NEW CINGULAR WIRELESS SERVICES, INC.

                      (F/K/A AT&T Wireless Services, Inc.),

                             CINGULAR WIRELESS LLC,

                            CINGULAR WIRELESS II, LLC

                       (F/K/A Cingular Wireless II, Inc.),

                                    AT&T INC.

                                       AND

                         U.S. BANK NATIONAL ASSOCIATION
                                     Trustee

                                   ----------

                          THIRD SUPPLEMENTAL INDENTURE

                          Dated as of December 29, 2006

            THIRD SUPPLEMENT TO INDENTURE DATED AS OF APRIL 11, 2002

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     THIRD SUPPLEMENTAL INDENTURE, dated as of December 29, 2006, by and among
New Cingular Wireless Services, Inc. (f/k/a AT&T Wireless Services, Inc.), a
Delaware corporation (the "Company"), Cingular Wireless LLC, a Delaware limited
liability company ("Cingular Wireless"), Cingular Wireless II, LLC (f/k/a
Cingular Wireless II, Inc., a Delaware limited liability company ("Cingular
Wireless II")), AT&T Inc., a Delaware corporation ("AT&T" and, together with
Cingular Wireless, and Cingular Wireless II, the "Co-Obligors"), and U.S. Bank
National Association, a national banking association, as Trustee (the
"Trustee").

                                    RECITALS

     WHEREAS, the Company and the Trustee have heretofore executed and delivered
a certain indenture, dated as of April 11, 2002 (as supplemented and amended,
the "Indenture"), pursuant to which the Company has issued its 6.875% Senior
Notes due April 18, 2005 (paid at maturity), its 7.500% Senior Notes due May 1,
2007 (the "2007 Notes") and its 8.125% Senior Notes due May 1, 2012 (the "2012
Notes"), and which provides for the issuance from time to time of its unsecured
debentures, notes and other evidences of indebtedness (together with the 2007
Notes and the 2012 Notes, the "Securities");

     WHEREAS, the Company and the Trustee have heretofore executed and delivered
a Supplemental Indenture, dated as of September 1, 2004 (the "First Supplemental
Indenture"), to the Indenture;

     WHEREAS, the Company, Cingular Wireless, Cingular Wireless II and the
Trustee have heretofore executed and delivered a Supplemental Indenture, dated
as of October 26, 2004 (the "Second Supplemental Indenture"), to the Indenture;

     WHEREAS, Section 8.1 of the Indenture permits entering into, at any time
and from time to time, without the consent of any Holders, one or more
indentures supplemental to the Indenture for the purposes of, among other
things, curing any ambiguity, defect or inconsistency contained in the
Indenture, and making other provisions with respect to matters or questions
arising under the Indenture, provided that such action shall not adversely
affect the interests of the Holders of Securities of any series in any material
respect;

     WHEREAS, AT&T has become the owner, directly or indirectly, of all the
issued and outstanding common stock of Cingular Wireless Corporation, the
manager of Cingular Wireless, and, directly or indirectly, all of the equity
interests in the Co-Obligors and wishes to become a "Co-Obligor" within the
meaning of Section 2.2(a) hereof;

     WHEREAS, this Third Supplemental Indenture is being effected pursuant to
Section 8.1 of the Indenture;

     WHEREAS, the Company has furnished the Trustee with (i) an Opinion of
Counsel to the Company stating that this Third Supplemental Indenture complies
with the applicable provisions of the Indenture, and (ii) an Officers'
Certificate stating that this Third Supplemental Indenture complies with the
applicable provisions of the Indenture; and

     WHEREAS, all things necessary to make this Third Supplemental Indenture a
valid, binding and legal agreement of the Company, the Co-Obligors, AT&T and the
Trustee and a valid amendment of and supplement to the Indenture have been done.

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     NOW, THEREFORE, THIS THIRD SUPPLEMENTAL INDENTURE WITNESSETH:

     For and in consideration of the premises, and for other good and valuable
consideration the receipt of which is hereby acknowledged, the Company, the
Co-Obligors and the Trustee hereby agree as follows:

                                    ARTICLE I
                                   DEFINITIONS

Section 1.1 Definitions.

     For all purposes of this Third Supplemental Indenture, except as otherwise
stated herein, capitalized terms used herein but not otherwise defined in this
Third Supplemental Indenture shall have the respective meanings assigned to them
in the Indenture. Each reference to "herein", "hereof" and "hereunder" and other
words of similar import contained in the Indenture shall, after this Third
Supplemental Indenture becomes effective, refer to the Indenture as supplemented
hereby.

                                   ARTICLE II
                                    AMENDMENT

Section 2.1 Amendment of Introductory Paragraph.

     The first paragraph of the Indenture immediately preceding the first
recital is hereby deleted and replaced in its entirety by the following:

"INDENTURE, dated as of April 11, 2002, among AT&T Wireless Services, Inc., a
Delaware corporation (the "Company"), Cingular Wireless LLC, a Delaware limited
liability company ("Cingular Wireless"), Cingular Wireless II, Inc., a Delaware
corporation ("Cingular Wireless II"), AT&T Inc., a Delaware corporation ("AT&T",
which, together with Cingular Wireless and Cingular Wireless II, shall be
Co-Obligors under this Indenture) and U.S. Bank National Association, a national
banking association organized under the laws of the United States, as Trustee."

Section 2.2 Addition of Certain Definitions.

          The definition of "Co-Obligors" in Section 1.01 of the Indenture is
hereby deleted and replaced in its entirety by the following:

     "CO-OBLIGOR" means each of Cingular Wireless, Cingular Wireless II, AT&T,
any Person that shall have become the successor to Cingular Wireless, Cingular
Wireless II or AT&T pursuant to the applicable provisions of this Indenture, and
any other Corporation that shall have fully, unconditionally and irrevocably
assumed and agreed to perform and discharge, or guaranteed the performance and
discharge of, jointly and severally with the Company and any other Co-Obligor of
the Securities, the obligation to pay the principal of, and interest and
Additional Amounts, if any, on, the Securities on the dates and in the manner
provided herein and in the Securities."

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Section 2.3 Amendment of Section 9.7 of the Indenture.

          All references to "the Company" contained in Section 9.7 of the
Indenture shall be understood to refer to, and at all times since the execution
of the Second Supplemental Indenture to have referred to, any Co-Obligor.

                                   ARTICLE III
                                  MISCELLANEOUS

Section 3.1 Effectiveness.

     The amendments to the Indenture set forth in Article II of this Third
Supplemental Indenture shall only become effective upon the execution of this
Third Supplemental Indenture in accordance with the requirements of the
Indenture.

Section 3.2 Confirmation of Indenture.

     As amended and modified by this Third Supplemental Indenture, the Indenture
is in all respects ratified and confirmed and the Indenture and this Third
Supplemental Indenture shall be read, taken and construed as one and the same
instrument.

Section 3.3 Governing Law.

     This Third Supplemental Indenture shall be governed by and construed in
accordance with the law of the State of New York without regard to conflicts of
law principles thereof.

Section 3.4 Counterparts.

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

Section 3.5 Successors and Assigns.

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

Section 3.6 Conflicts.

     In the event of a conflict between the terms and conditions of the
Indenture and the terms and conditions of this Third Supplemental Indenture, the
terms and conditions of this Third Supplemental Indenture shall prevail.

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

NEW CINGULAR WIRELESS SERVICES, INC.
(F/K/A AT&T Wireless Services, Inc.)

By /s/ Sean Foley
   ----------------------------------
Name: Sean Foley
Title: Vice President - Treasurer

CINGULAR WIRELESS LLC

By: CINGULAR WIRELESS CORPORATION,
    as Manager

By /s/ Sean Foley
   ----------------------------------
Name: Sean Foley
Title: Vice President - Treasury and
       Corporate Development

CINGULAR WIRELESS II, LLC
(F/K/A Cingular Wireless II, Inc.)

By: CINGULAR WIRELESS CORPORATION,
    as Manager

By: /s/ Sean Foley
    ---------------------------------
Name: Sean Foley
Title: Vice President - Treasury and
       Corporate Development

AT&T Inc.

By /s/ Charles P. Allen
   ----------------------------------
Name: Charles P. Allen
Title: Managing Director - Assistant
       Treasurer

U.S. BANK, National Association
as Trustee

By /s/ Raymond S. Haverstock
   ----------------------------------
Name: Raymond S. Haverstock
Title: Vice President<PAGE>

                                                                     EXHIBIT 4.3

                              GUARANTEE UNDERTAKING
                                       OF
                             THE ASSISTANT TREASURER
                                       OF
                                    AT&T INC.

          I, Charles P. Allen, the Assistant Treasurer of AT&T Inc. (the
"Corporation"), pursuant to the authority granted to me in the Schedule of
Authorizations of the Corporation, dated as of November 18, 2005, hereby
undertake on behalf of the Corporation for the benefit of the respective holders
of the Subject Debt Security (as defined below), as follows:

     (1) The Corporation hereby unconditionally and irrevocably guarantees the
     punctual and full payment of all amounts payable by BellSouth Corp. under
     the outstanding Subject Debt Security as and when the same shall become due
     and payable (whether at stated maturity, by declaration of acceleration,
     call for redemption, repayment at the option of the holder or otherwise, in
     accordance with the terms of the Subject Debt Security and of the indenture
     under which such security was issued) (the "Guarantee").

     (2) The Guarantee with respect to the outstanding Subject Debt Security
     will continuously remain in effect until the entire principal of (and
     premium, if any) and interest, if any, on such Subject Debt Security shall
     have been paid in full.

     (3) The Guarantee will constitute the direct, absolute and unconditional,
     unsubordinated and unsecured obligation of the Corporation ranking pari
     passu with all of its unsecured and unsubordinated obligations.

     (4) The holders of the Subject Debt Security are entitled to enforce their
     rights under the indenture relating to such security directly against the
     Corporation, without first instituting a proceeding against the issuer of
     such security or any other person or entity, upon any event of default in
     payment of principal, or premium, if any, or interest, if any, on such
     security (whether at stated maturity, by declaration of acceleration, call
     for redemption, repayment at the option of the holder or otherwise).

     (5) This Guarantee undertaking is enforceable to the fullest extent
     permitted by law.

     (6) For the purposes of this Guarantee undertaking, the term "Subject Debt
     Security" shall mean the following:

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     BellSouth Corp.'s Two Year Floating Rate Notes due August 15, 2008 ($1.2
     billion principal amount).

     (7) The Guarantee is effective on the date hereof.

          IN WITNESS WHEREOF, I have executed this Guarantee undertaking.

Dated: December 29, 2006

                                        /s/ Charles P. Allen
                                        ----------------------------------------
                                        Name: Charles P. Allen
                                        Title: Managing Director - Assistant
                                               Treasurer

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