<PAGE>
                                                                   EXHIBIT 10.66

                       ASSIGNMENT AND COLLECTION AGREEMENT



         THIS ASSIGNMENT AND COLLECTION AGREEMENT (this "Agreement") is entered
into this 5th day of December, 2002, by and between NACT TELECOMMUNICATIONS,
INC., a Delaware corporation ("NACT"), and WA TELCOM PRODUCTS CO., INC., a
Delaware corporation ("WATP").

                              W I T N E S S E T H:
                               - - - - - - - - - -

         WHEREAS, NACT is the holder of certain receivables arising from
equipment and services sold by NACT prior to July 27, 2001, a list of which
receivables is attached hereto as EXHIBIT A (the "Receivables");

         WHEREAS, pursuant to Section 2 of that certain Settlement Agreement,
dated as of November 6, 2002, between Verso Technologies, Inc. ("Verso") and
WATP, Verso agreed to cause NACT to assign and transfer the Receivables to WATP;
and

         WHEREAS, in order to effectuate such assignment and set forth the
parties' understanding with respect to certain other matters related to the
Receivables, NACT and WATP have agreed to execute and deliver this Agreement;

         NOW, THEREFORE, in consideration of the terms and conditions contained
herein and other valuable consideration, the receipt and adequacy of which the
parties hereby acknowledge, NACT and WATP hereby agree as follows:

1.       Assignment.

         (a)      NACT hereby assigns, transfers, conveys, delivers, abandons
                  and sets over unto WATP, its successors and assigns, all of
                  NACT's right, title and interest in and to the Receivables and
                  any and all promissory notes, instruments and other evidences
                  of indebtedness related thereto, including any and all
                  security interests in equipment relating thereto.

         (b)      NACT will from time to time and at all times hereafter, upon
                  the request of WATP, do, execute, acknowledge and deliver or
                  cause to be done, executed, acknowledged and delivered all
                  such further acts, deeds, assignments, transfers, conveyances,
                  powers of attorney, and assurances as may be required in order
                  to more fully effectuate the purposes and intents of Section
                  1(a) hereof.

2.       Collection of Receivables.

         (a)      From and after the date hereof, NACT shall use its
                  commercially reasonable efforts to (i) collect on behalf of
                  WATP, as WATP's exclusive


<PAGE>


                  agent, all of the Receivables, and (ii) exercise and enforce,
                  as WATP's exclusive agent, WATP's rights as an owner or as a
                  secured party, as the case may be, with respect to the
                  Receivables to the extent of such rights, which shall include
                  the right to repossess, refurbish and resell any equipment
                  securing the Receivables (the "Returned Equipment"). NACT
                  shall not have the right to compromise, settle or adjust the
                  amount of the Receivables, or any installment or periodic
                  payment with respect thereto, without WATP's prior consent;
                  provided however, that if WATP fails to consent within five
                  (5) business days following NACT's request for such consent,
                  WATP shall be deemed to have consented to any such compromise,
                  settlement or adjustment.

         (b)      Within fifteen (15) days after the end of each calendar month,
                  NACT shall remit to WATP a portion of the Net Collection
                  Amount (as defined herein) determined in accordance with the
                  following table:


                  PORTION REMITTED
                     TO  WATP                NET COLLECTION AMOUNT

                  50%                      Up to $50,000
                  60%                      In excess of $50,000 to $75,000
                  70%                      In excess of $75,000


         (c)      For purposes hereof, "Net Collection Amount" shall mean the
                  amount of any and all funds collected (measured upon receipt)
                  by NACT in respect of the Receivables (excluding any proceeds
                  from the sale of any Returned Equipment) during a calendar
                  month less NACT's actual out-of-pocket expenses to third
                  parties incurred in connection with its collection efforts
                  during such month. NACT shall, upon request by WATP, provide
                  to WATP a written accounting describing in reasonable detail
                  NACT's collection efforts during the applicable month or
                  months, including, without limitation, costs and expenses
                  incurred by NACT in connection therewith.

         (d)      Upon receipt by NACT of the Returned Equipment, NACT shall use
                  its commercially reasonable efforts to sell the Returned
                  Equipment, and within fifteen (15) days after the end of each
                  calendar month, NACT shall remit to WATP an amount equal to
                  50% of the cost of the Returned Equipment sold during such
                  calendar month, where the cost of such Returned Equipment will
                  be as set forth on a cost schedule to be agreed upon by NACT
                  and WATP and attached hereto as EXHIBIT B within thirty (30)
                  days of the date hereof.


                                       2
<PAGE>


3.       Miscellaneous.

         (a)      All notices and other communications required or permitted
                  under this Agreement shall be in writing and shall be deemed
                  given when delivered personally, mailed by certified mail
                  (postage pre-paid and return receipt requested), sent by
                  overnight courier service or faxed (transmission confirmed),
                  or otherwise actually received. All such notices and other
                  communications shall be delivered, mailed, couriered or faxed,
                  (i) if to WATP, at Resurgens Plaza, Suite 2210, 945 East Paces
                  Ferry Road, Atlanta, GA (Facsimile No.: 404-233-2280),
                  Attention: Michael F. Mies, and (ii) if to NACT, at 400
                  Galleria Parkway, Suite 300, Atlanta, GA 30339 (Facsimile No.:
                  678-589-3750), Attention: Steven A. Odom, or at such other
                  address as WATP or Verso may designate in writing to the other
                  party.

         (b)      This Agreement shall be governed and construed in accordance
                  with the laws of the State of Georgia (without giving effect
                  to choice of law principles thereof). Each of the parties
                  hereto irrevocably agrees that any legal action or proceeding
                  with respect to this Agreement or the transactions
                  contemplated hereby, or for recognition and enforcement of any
                  judgment in respect hereof, brought by the other party hereto
                  or any of its successors or assigns shall be brought and
                  determined in the United States Bankruptcy Court for the
                  Northern District of Illinois, Eastern Division (the "Court"),
                  and each party hereby irrevocably submits with respect to any
                  such action or such proceeding for itself and in respect of
                  its property, generally and unconditionally, to the exclusive
                  jurisdiction of the Court.

         (c)      This Agreement may be executed in two or more counterparts,
                  each of which shall be deemed an original but all of which
                  together shall constitute one and the same instrument.

         (d)      This Agreement may be amended only by a written instrument
                  signed by all of the parties hereto. No failure to exercise
                  and no delay in exercising, on the part of any party, any
                  right, remedy, power or privilege hereunder, shall operate as
                  a waiver thereof; nor shall any single or partial exercise of
                  any right, remedy, power or privilege hereunder preclude any
                  other or further exercise thereof or the exercise of any other
                  right, remedy, power or privilege. The rights, remedies,
                  powers and privileges herein provided are cumulative and not
                  exclusive of any rights, remedies, powers and privileges
                  provided by law.

         (e)      All rights, covenants and agreements of the parties contained
                  in this Agreement shall be binding upon and inure to the
                  benefit of their respective successors and assigns (including,
                  without limitation, any trustees or liquidators). This
                  Agreement, and the rights and obligations



                                       3
<PAGE>


                  hereunder, may not be assigned by either party without the
                  prior written consent of the other party.





                         [SIGNATURES ON FOLLOWING PAGE]




                                       4
<PAGE>




         IN WITNESS WHEREOF, the parties have caused this Agreement to be
executed by their duly authorized officers as of the date first written above:

                                        WATP:

                                        WA TELCOM PRODUCTS CO., INC.


                                        By:   /s/ W. Tod Cumor
                                           -------------------------------------
                                        Name:  W. Tod Cumor
                                             -----------------------------------
                                        Title:  Secretary
                                              ----------------------------------


                                        NACT:

                                        NACT TELECOMMUNICATIONS, INC.


                                        By:   /s/ Juliet M. Reising
                                           -------------------------------------
                                        Name:  Juliet M. Reising
                                        Title: Vice President





<PAGE>


                                    EXHIBIT A

                                   RECEIVABLES

ACS Telecom, Inc.

Ariana Telecommunications, Inc.

Dime Communications, Inc.

JD Services, Inc.

JFJ Communications, Inc.

Leading Edge Broadband Services, Inc.

Los Amigos Telecom, Inc.

Money Travel Services, Inc.

Nexstar Communications, Inc.

Orion Telecommunications Corporation (two notes, #1 and #2)

Progresam S.A.

Thai American Telecommunication, Inc.

Total Call International, Inc.

U.S. Satellite Telecommunications, Corp.

Voice Vision International, Inc.

UDC Telecommunications, Inc.

Xenon Communications, Inc.

Y&B Services Corp.








<PAGE>

                                   EXHIBIT B
                      COST SCHEDULE OF RETURNED EQUIPMENT

NACT TELECOMMUNICATIONS, INC.
STX AND MCU COST SUMMARY

<Table>
<S>                                 <C>         <C>            <C>                                 <C>         <C>
STX - NEG 48 SYSTEM                                            STX - 120 VOLT SYSTEM
    Bay and main assembly           13,848.11                      Bay and main assembly           13,492.65
    T-1 boards                         933.32   per board          T-1 boards                         933.32   per board
    DSP boards                       1,044.38   per board          DSP Boards                       1,044.38   per board
    E1/ISDN/SS7 boards                                             E1/ISDN/SS7 boards                 915.39
      1 board                          915.39                        1 board                          915.39
      2 boards                       1,830.78                        2 boards                       1,830.78
      3 boards                       2,746.17                        3 boards                       2,746.17
      4 boards                       3,661.56                        4 boards                       3,661.56
      5 boards                       4,576.95                        5 boards                       4,576.95
      6 boards                       5,492.34                        6 boards                       5,492.34
      7 boards                       6,407.73                        7 boards                       6,407.73
      8 boards                       7,323.12                        8 boards                       7,323.12
      9 boards                       8,238.51                        9 boards                       8,238.51
      10 boards                      9,153.90                        10 boards                      9,153.90
    Neg 48 to 120V inverter option   2,529.18                      Neg 48 to 120V inverter option     N/A
    18 GIG HD option                   189.11                      18 GIG HD option                   189.11
    RAID System option              13,663.00                      RAID System option              13,663.00
    UPS Option                         N/A                         UPS Option                       1,136.00
</Table>

<Table>
<S>                                 <C>         <C>            <C>                                 <C>         <C>
MCU - NEG 48 SYSTEM                                            MCU 120 VOLT SYSTEM
    Bay and main assembly            6,623.88                      Bay and main assembly            5,945.19
    RAID option                     13,663.00                      RAID option                     13,663.00
    2nd RAID system option          11,345.00                      2nd RAID system option          11,345.00
    Spare Turbo CPU option           1,633.61                      Spare Turbo CPU option           1,633.61
    Neg 48 to 120V inverter option   2,529.18                      Neg 48 to 120V inverter option     N/A
    UPS option                         N/A                         UPS option                       1,136.00
    Spare power tray option          1,012.63                      Spare power tray option            368.18
    Modem option                       415.00   per modem          Modem option                       415.00   per modem
</Table>