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                                                                   EXHIBIT 10.21

                                 PROMISSORY NOTE


$ 250,000.00                           Dated: SEPT. 29, 2001

Principal Amount                       State of TEXAS

(TWO HUNDRED FIFTY TH0USAND AND NO/100 DOLLARS)

         FOR VALUE RECEIVED, the undersigned hereby jointly and severally
promise to pay to the order of OSCAR S. WYATT, JR.,

                                                                     ,the sum of
TWO HUNDRED FIFTY THOUSAND AND NO/100 -- Dollars ($250,000,000) together with
interest thereon at the rate of 8 % per annum on the unpaid balance. Said sum
shall be paid in the manner following:

TOTAL DUE ONE YEAR FROM SEPTEMBER 29, 2001 PLUS INTEREST



         All payments shall be first applied to interest and the balance to
principal. This note may be prepaid, at any time, in whole or in part, without
penalty. All prepayments shall be applied in reverse order of maturity.

         This note shall at the option of any holder hereof be immediately due
and payable upon the failure to make any payment due hereunder within 30 days of
its due date.

         In the event this note shall be in default, and placed with an attorney
for collection, then the undersigned agree to pay all reasonable attorney fees
and costs of collection. Payments not made within five (5) days of due date
shall be subject to a late charge of   % of said payment. All payments hereunder
shall be made to such address as may from time to time be designated by any
holder hereof.

         The undersigned and all other parties to this note, whether as
endorsers, guarantors or sureties, agree to remain fully bound hereunder until
this note shall be fully paid and waive demand, presentment and protest and all
notices thereto and further agree to remain bound, notwithstanding any
extension, renewal, modification, waiver, or other indulgence by any holder or
upon the discharge or release of any obligor hereunder or to this note, or upon
the exchange, substitution, or release of any collateral granted as security for
this note. No modification or indulgence by any holder hereof shall be binding
unless in writing; and any indulgence on any one occasion shall not be an
indulgence for any other or future occasion. Any modification or change of
terms, hereunder granted by any holder hereof, shall be valid and binding upon
each of the undersigned, notwithstanding the acknowledgment of any of the
undersigned, and each of the undersigned does hereby irrevocably grant to each
of the others a power of attorney to enter into any such modification on their
behalf. The rights of any holder hereof shall be cumulative and not necessarily
successive. This note shall take effect as a sealed instrument and shall be
construed, governed and enforced in accordance with the laws of the State first
appearing at the head of this note. The undersigned hereby execute this note as
principals and not as sureties.

Signed in the presence of:

 /s/ RICHARD WATSON                          /s/ HERMAN M. FRIETSCH
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Witness                                  Borrower
                                         TERAFORCE TECHNOLOGY CORPORATION

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Witness                                  Borrower
                                         HERMAN FRIETSCH, CEO

                                    GUARANTY

         We the undersigned jointly and severally guaranty the prompt and
punctual payment of all moneys due under the aforesaid note and agree to remain
bound until fully paid.

In the presence of:

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Witness                                  Guarantor

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Witness                                  Guarantor