ADELPHIA COMMUNICATIONS CORPORATION
                              ONE NORTH MAIN STREET
                         COUDERSPORT, PENNSYLVANIA 16915


                                November 23, 1999


Adelphia Business Solutions, Inc.
One North Main Street
Coudersport, Pennsylvania  16915

         Re:      Purchase of Shares of Adelphia Business Solutions, Inc.'s
                  Class B Common Stock, $.01 par value per share

Gentlemen:

         The undersigned hereby agrees to purchase directly from you, and you
agree to sell to the undersigned, upon the terms and subject to the conditions
set forth herein, an aggregate of 5,181,350 shares (the "Shares") of Class B
Common Stock, $.01 par value per share of Adelphia Business Solutions, Inc., a
Delaware corporation (the "Company"), at a purchase price of $28.95 per share.
Each capitalized term used herein without being defined herein shall have the
meaning ascribed to it in the Underwriting Agreement, of even date herewith (the
"Underwriting Agreement"), among the Company and Salomon Smith Barney, Inc. and
the other underwriters named therein (together, the "Underwriters"), with
respect to the offering and sale of 8,750,000 shares (excluding the
over-allotment option) of the Company's Class A Common Stock, $.01 par value per
share (the "Class A Common Stock).

         Each of the parties hereto represents and warrants that it has full
power and is duly authorized to enter into and perform this agreement; that it
has all necessary corporate approvals; that the execution and performance of
this agreement will not conflict with the organic corporate documents of it or
any order of a governmental body or agency (subject to any regulatory approvals
or regulatory filings and expiration of waiting periods required by law) or
material agreement to which it is a party or by which it is bound; and that this
Agreement is enforceable in accordance with it terms, subject as to enforcement
to bankruptcy, insolvency, reorganization, fraudulent conveyance and other laws
of general applicability relating to or affecting creditors rights and to
general equity principles. The Company also makes to the undersigned, and agrees
that the undersigned is entitled to rely on, the representations and warranties
made by the Company in the Underwriting Agreement; provided, however, that the
undersigned represents and warrants to the Company that such representations and
warranties are true and correct to the best of its knowledge.

         The purchase and sale of the Shares as contemplated hereby shall take
place on the Closing Date concurrently with the closing on the Class A Common
Stock with the Underwriters. No commissions or discounts shall be paid to any
placement agent for such purchase or sale of the Shares. The Shares shall be
purchased and shall be held for investment. It is agreed that the Shares shall
be subject to all the rights and benefits of the Registration Rights Agreement
dated as of October 25, 1996, as amended, between Adelphia Communications
Corporation and the Company, and shall constitute Registrable Securities
thereunder. It is further agreed that in connection with the offering or sale of
the Class A Common Stock pursuant to the Underwriting Agreement, Adelphia
Communications Corporation waives any piggyback registration rights it may have
or may have had with respect to any shares of the Company's Class A or Class B
Common Stock owned or controlled by it.

         Each party's obligations hereunder shall be conditioned upon the
concurrent or prior closing on the purchase and sale of the Class A Common Stock
as contemplated by the Underwriting Agreement, any required approvals having
been obtained, any required filings having been made and any required waiting
periods having expired, and the other party's representations and warranties
being true and correct on and as of the closing date for the sale of the Shares
hereunder (except (i) for representations and warranties which expressly relate
solely to an earlier date or time, which representations or warranties shall be
true and correct on and as of the specific dates or times referred to therein
and (ii) for representations and warranties which are not true and correct due
to matters subsequent to the date of the closing of Underwriting Agreement which
have occurred in the Company in the ordinary course of its business, which have
occurred in the Company and been authorized by the Board of Directors of the
Company or which have occurred in the Company and been authorized by any
individual affiliate of the undersigned who is an executive officer of the
Company). This Agreement shall be terminated without liability on the part of
any party hereto in the event that the Underwriting Agreement is terminated.

         This Agreement shall be effective upon execution and delivery, by the
parties thereto, of the Underwriting Agreement.

         This Agreement may be executed in one or more counterparts each of
which, taken together, shall constitute one and the same agreement.

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         This Agreement shall be governed by and construed in accordance with
the internal laws of the State of New York without giving effect to the
principles of conflicts of law thereof.

                                         Very truly yours,

                                         ADELPHIA COMMUNICATIONS CORPORATION


                                         By: /s/ James R. Brown
                                             Name: James R. Brown
                                             Title: Vice President




Agreed to and accepted by on this 23rd day of November, 1999.

ADELPHIA BUSINESS SOLUTIONS, INC.


By: /s/ John Glicksman
     Name: John Glicksman
     Title: Vice President and General Counsel