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                                                                    EXHIBIT 10.5

                                                           Agreement No. 4569177
                                                                 Amendment No. 4
                                                                     Page 1 of 2

                                        ACCEPTANCE SHALL BE INDICATED BY
                                        SIGNING AND RETURNING DUPLICATE

TO:                                           FROM:

PF.Net Corp.                                  AT&T Corp.
1800 Alexander Bell Drive                     1200 Peachtree Street
4th Floor                                     Room 09E30
Reston, VA 20191                              Atlanta, GA  30309
Attn.: Donald L. Branscome                    Attn.: Lynn O. Pardue

General Purchase Agreement Number 4569177 ("Agreement") between AT&T Corp.
("AT&T") and PF.Net, Corp. ("Builder") dated October 29,1999 and as-modified by
Amendment Nos. 1, 2 and 3, is further modified by Amendment Number 4 as follows:

1.   ARTICLE 3.6.A: SUPPLY OF OA BUILDINGS: The following language is deleted
     from the Agreement in its entirety:

          "3.6.A SUPPLY OF OA BUILDINGS: Builder agrees to supply to AT&T new
          Optical Amplifier ("OA") buildings (the "Supplied Services") at the
          Builder sites identified in "Exhibit 3B: Links and Optical Amplified
          Locations" (the "Shared Sites"). It is contemplated that the new AT&T
          OA buildings will share the slab on which the adjacent Builder
          buildings are or may be located. The Supplied Services to be supplied,
          in addition to the other elements described in Article 3.6.A through
          3.6.O, includes but is not limited to the following:

          (1)    Planning, engineering, construction and placement of the OA
                 building specified in Exhibit 3A of this Amendment;

          (ii)   Supervision and Inspection of the pre-fabricated buildings
                 during fabrication and installation of the OA buildings;

          (iii)  Assurance that the pre-fabricated OA building supplied by
                 Builder will be in accordance with the drawings and
                 specifications as set forth in Exhibit 3A of this Amendment;

          (iv)   Arrangement and installation of cable conduit for connection to
                 the OA buildings;

                            AT&T/Builder Proprietary
10/01/FINAL

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                                                           Agreement No. 4569177
                                                                 Amendment No. 4
                                                                     Page 2 of 2

          (v)    Necessary engineering and construction services for the purpose
                 of power and communication cables entering and passing through
                 Builder's main building to the AT&T building;

          (vi)   Support the installation of AT&T's cable locating devices and
                 Isolation closure in the Builder main OA builder and
                 connections to the appropriate equipment in the AT&T building;

          In return for these construction services, AT&T will pay the Builder
          Two Hundred Thousand Dollars ($200,000.00) for each OA site
          constructed by the Builder. All Builder Invoices are due within thirty
          (30) days of construction completion and site acceptance by AT&T but
          in no event prior to January 1, 2002.

          Upon mutual agreement by AT&T and Builder. this Section 3.6.A may be
          superceded by a separate Construction Services Agreement between the
          Builder and AT&T for the construction of OA sites which would include
          terms substantially similar to the terms described in this amended
          Section 3.6.A."

This Amendment No. 4 is effective as of the execution of this Amendment by both
parties and shall be incorporated in and shall constitute a part of the
Agreement as if fully set forth therein. EXCEPT AS AMENDED HEREIN, ALL TERMS AND
CONDITIONS OF THE AGREEMENT REMAIN UNCHANGED.

APPROVAL:

ACKNOWLEDGED AND AGREED TO BY:

PF.NET CORP.                             AT&T CORP.

By: /s/ DONALD L. BRANSCOME           By: /s/ DIANA L. JONES
    ---------------------------           --------------------------------------
    (signature)                           (signature)

Name:  Donald L. Branscome               Name:  Diana L. Jones

Title: Senior Vice President-            Title: Group Procurement Director, AT&T
       Business Development                     Supplier Management
       ------------------------                 --------------------------------

Date:  Oct. 18, 2001                     Date:  October 22, 2001
       ------------------------                 --------------------------------
       (typed or printed)                       (typed or printed)

                            AT&T/Builder Proprietary
10/01/FINAL