Exhibit 4.04
                                                                   ------------
                              NEMATRON CORPORATION


                                 PROMISSORY NOTE


$1,700,000                                                        July 16, 2003

         For value received, NEMATRON CORPORATION, a Michigan corporation
(the "Company"), promises to pay to the order of NORTH COAST TECHNOLOGY
INVESTORS, LP., at 206 S. Fifth Avenue, Ann Arbor, Michigan 48104 ("North
Coast"), or its permitted assigns, the principal sum of ONE MILLION SEVEN
HUNDRED THOUSAND DOLLARS ($1,700,000), or so much thereof as is advanced
hereunder from time to time. Interest hall be payable on the unpaid principal
balance of this Note, computed on the basis of actual number of days elapsed,
from the date hereof at the rate of nine percent (9%) per annum. The principal
of and interest on this Note shall be paid in lawful money of the United States
upon demand therefore by the holder hereof. All payments received shall be
applied first to accrued interest and the balance shall be applied to principal.

         North Coast shall advance to the Company up to the principal amount set
forth above, from time to time upon the request of the Company, provided that
each and every advance shall be made or declined in the sole discretion of North
Coast, and North Coast shall have no liability to the Company for its failure or
refusal to make any advance.

         Notwithstanding the foregoing, the Company shall pay interest on demand
at the rate of fourteen percent (14%) per annum on the outstanding principal
amount of the Promissory Note, all accrued and unpaid interest, and all other
amounts due under this Note which are not paid in full when due for the period
commencing on the due date thereof until the same are paid in full.

         The Company acknowledges that this Note matures upon issuance, and that
the holder of this Note, at any time, without reason, may demand that this Note
be immediately paid in full.

         This Note may be paid prior to demand, without penalty, in whole or in
part at any time and from time to time after issue at the option of the Company.

         As security for the payment of this Note, the Company grants North
Coast, its successors and assigns, a continuing security interest in all assets
of the Company.

         The proceeds of advances to the Company shall be used only for product
development, expansion of marketing and sales activities and to fund working
capital (including the repayment of the Company's operating line of credit).

         The Company shall pay all expenses, court costs and reasonable
attorneys' fees which may be incurred by or on behalf of this Note in connection
with the collection of or attempts to collect any amounts due under this Note.

         The Company and each endorser hereof waive demand, presentment,
protest, diligence, notice of dishonor, and any other formality in connection
with this Note.

         This Note shall be governed by the laws of the State of Michigan.

                                        NEMATRON CORPORATION


                                        By: /s/ Tina M. Raiford
                                            -------------------
                                        Its: Controller