EXHIBIT 10.1

                              [Comcast Letterhead]


                                January 11, 2001


FAX AND FEDERAL EXPRESS

AT&T Corp.
295 North Maple Avenue
Basking Ridge, NJ 07920

Attention: Marilyn Wasser, Vice President - Law and
                           Corporate Secretary


Dear Marilyn:

     Reference is hereby made to the letter agreement dated March 28, 2000
among At Home Corporation, AT&T Corp., Comcast Corporation, Cox Communications,
Inc. and certain of their respective subsidiaries (the "Letter Agreement") and
the term sheets attached thereto as Annexes A, B and C (collectively, the "Term
Sheets"). Capitalized terms used herein and not otherwise defined have the
meanings ascribed to them in the Letter Agreement and Term Sheets.

     Comcast hereby exercises the Put in accordance with the terms and
provisions of the Letter Agreement and Term Sheet Annex A.

     Comcast is electing to have the purchase price under the Put paid in AT&T
Shares, the exact number of which will be calculated in accordance with the
terms of paragraph (b) of Term Sheet Annex A. To facilitate such an arrangement
in accordance with paragraph (c) of Term Sheet Annex A, Comcast hereby proposes
that it exchange its shares of Comcast PC Investments, Inc. which at the
closing of the Put will hold 31,253,180 Series A Shares, with AT&T for AT&T
Shares in a transaction intended to qualify as a tax-free reorganization under
Section 368 of the Internal Revenue Code. Based on current market conditions,
Comcast has assumed that the purchase price under the Put will be $48 per
share.





     Please feel free to call either the undersigned at (215) 981-7564 or
Robert Pick at (215) 981-7367 to discuss the arrangements for closing the
transaction described above as promptly as possible.


                                            Very truly yours,

                                            COMCAST CORPORATION

                                            By:  /s/ Arthur R. Block
                                               ---------------------------------
                                               Name:   Arthur R. Block
                                               Title:  Senior Vice President