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                                                                    EXHIBIT 4.19

The following schedule sets forth the noteholders and amounts of such notes
issued pursuant to the Convertible Promissory Notes dated December 1, 1998:

<TABLE>
<CAPTION>
                   Noteholder                      Amount
<S>                                          <C>
Rhubarb Investment Club                           $50,000
James A. Nichols                                   50,000
Gregory Schwartz, Jr.                              33,000
Ralph E. Meisel Trust                              25,000
Gregory J. Schwartz Revocable Trust                25,000
Lawrence and Patricia Feeny                        25,000
Lisa Martin Hirs                                   10,000
Jeffrey and Kathleen Bell                          10,000
Scott and Marilyn Schumaker                         5,000
Patrick and Geraldine Carroll                       5,000
Peter C. Mitchell                                   5,000
Craig A. Maas                                       5,000
Tom Van Dusen                                       2,000
                                                 --------

Total                                            $250,000
                                                 ========
</TABLE>

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<PAGE>   2


THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED
(THE "SECURITIES ACT"), OR UNDER ANY OTHER SECURITIES LAWS. IT MAY NOT BE SOLD
OR OFFERED FOR SALE IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT AS TO
THIS NOTE UNDER THE SECURITIES ACT OR AN OPINION OF COUNSEL REASONABLY
SATISFACTORY TO THE PAYOR THAT SUCH REGISTRATION IS NOT REQUIRED.

                           CONVERTIBLE PROMISSORY NOTE

$_________________                                           December 1, 1998
                                                             Ann Arbor, Michigan

         FOR VALUE RECEIVED, the undersigned, Nematron Corporation, a Michigan
corporation (the "Payor"), hereby promises to pay to _________________, an
individual [corporation] (the "Payee"), at
___________________________________________, or at such other place or places as
the Payee may designate from time to time in writing to the Payor, in lawful
money of the United States of America and in immediately available funds, the
aggregate principal sum of _____________________________ ($_____________), and
to pay interest on the outstanding principal balance at the rate of seven
percent (7%) per annum, and after maturity or the occurrence of an event of
default hereunder, at the rate of nine percent (9%) per annum. The payment of
the principal and all accrued and unpaid interest thereon shall be due and
payable on March 31, 1999 (the "Maturity Date"). Interest shall be charged on
the basis of a year of 365 days.

         This Note may be prepaid at any time and from time to time, in whole
but not in part, without penalty or premium, upon five (5) days prior written
notice from the Payor to the Payee, unless, prior to such repayment, Payee
provides notice to Payor of its intent to exercise its conversion rights
provided in the third paragraph of this note (Payee's notice of intent to
exercise its conversion rights shall be effective notwithstanding Payor's notice
of intent to repay). This Note shall be payable or prepayable, at the sole
discretion of the Payor, in cash or the Payor's common stock ("Common Stock").
For the purpose of payment or prepayment of this Note, Common Stock shall be
valued at $.25 per share (the "Payment and Conversion Price").

         Subject to the terms and conditions set forth herein, the principal and
interest due and payable under this Note may be converted by Payee, in whole or
in part, into Common Stock upon fifteen (15) days prior written notice from the
Payee to the Payor and prior to the earlier of (i) the Maturity Date or (ii) the
prepayment in whole of this Note. The number of shares of Common Stock issuable
upon such conversion shall be the principal and interest then due and payable
under this Note divided by the Payment and Conversion Price, rounded down to the
nearest whole share. No fractional shares shall be issued upon conversion of
this Note. In the event any merger, reorganization, consolidation,
recapitalization, stock dividend or other change in corporate structure
affecting Common Stock occurs after the date hereof and prior to the Maturity
Date, an equivalent adjustment shall be made in the aggregate number of shares
which may be delivered upon conversion hereunder. Notwithstanding the foregoing
provisions of this paragraph, the Payor shall not be required to issue more than
_________ shares of Common Stock to the Payee pursuant to this paragraph unless
the issuance of any additional shares (if aggregated with all other issuances
and potential issuances of Common Stock pursuant to this Note and the other
notes issued by the Payor on the date hereof and upon exercise of the Options
granted pursuant to the other notes issued by the Payor on the date hereof) has
been approved by the shareholders of the Payor to the extent required by
applicable law, Payor's organizational documents or the rules of the Nasdaq
Stock Market (the "Required Approval"). Any portion of the principal or interest
under this Note which Payee attempts to convert into Common Stock but which
cannot be converted due to the limitation in the immediately preceding sentence
shall remain outstanding under this Note until otherwise paid, prepaid or
converted.

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         The Payor agrees to file one registration statement with the Securities
and Exchange Commission to register the shares of its Common Stock issued upon
payment or conversion of this Note (if any following the issuance of such
shares, in accordance with the terms and subject to the conditions of a
registration rights agreement to be negotiated and entered into by the Payor and
the Payee in a form reasonably satisfactory to both parties. Payor's failure to
comply with the foregoing obligation to register such shares or the obligations
in such registration rights agreement shall constitute an event of default under
this Note.


         THE PAYOR AND THE PAYEE, AFTER CONSULTING OR HAVING HAD THE OPPORTUNITY
TO CONSULT WITH COUNSEL, KNOWINGLY, VOLUNTARILY AND INTENTIONALLY WAIVE ANY
RIGHT EITHER OF THEM MAY HAVE TO A TRIAL BY JURY IN ANY LITIGATION BASED UPON OR
ARISING OUT OF THIS NOTE, OR ANY COURSE OF CONDUCT, DEALING, STATEMENT (WHETHER
ORAL OR WRITTEN) OR ACTIONS OF EITHER OF THEM. NEITHER THE PAYOR NOR THE PAYEE
SHALL SEEK TO CONSOLIDATE, BY COUNTERCLAIM OR OTHERWISE, ANY ACTION IN WHICH A
JURY TRIAL HAS BEEN WAIVED WITH ANY OTHER ACTION IN WHICH A JURY TRIAL CANNOT BE
OR HAS NOT BEEN WAIVED.

         The undersigned Payor hereby waives demand, presentment, protest,
dishonor and notice of dishonor in connection with this Note.

         In the event any action is taken to collect or enforce the indebtedness
evidenced by this Note or any part thereof, the undersigned agrees to pay, in
addition to the principal and interest due and payable hereon, all reasonable
costs of collecting this Note, including reasonable attorneys' fees and
expenses.

         Acceptance by the Payee of any payment in an amount less than the
amount then due and owing shall be deemed an acceptance on account only, and the
failure to pay the entire amount then due and owing shall cause the Payor to
remain in default.

         This Note may not be sold, assigned or otherwise transferred without
the prior written consent of Payor, which consent shall not be unreasonably
withheld. In all events, a transfer to Payee's revocable living trust shall be
allowed after written notice provided to the Payor.

         This Note is made under, and shall be governed by and construed in
accordance with, the laws of the State of Michigan as to notes made and
performed entirely within such State and without giving effect to choice of law
principles of such State.

         This Note was entered into as a last resort and in good faith. Payor
will not solicit from third parties offers or solicitations of offers for
purchase of shares until the Required Approvals are received or rejected;
provided that Payor shall be permitted to solicit offers to purchase additional
Option Notes as long as such Option Notes when sold do not have an aggregate
principal amount, together with the other notes issued by Payor on the date
hereof, exceeding $3 million; and further provided, that Payor's Board of
Directors, on behalf of Payor, may furnish information and may participate in
discussions and negotiations through its representatives with persons who have
sought the same if the failure to provide such information or participate in
such negotiations or discussions would cause the directors to breach their
fiduciary duties to Payor's shareholders under applicable law.

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<PAGE>   4
         Notwithstanding any provision in this Note to the contrary, Payor shall
not be required to issue any shares of Common Stock in excess of the number of
shares referenced in the third paragraph of this Note if any Required Approval
has not been received or if such issuance would constitute a violation of any
applicable Federal or state securities law or any other law or regulation. If
shareholder approval is required, Payor agrees to seek, as soon a practicable
following execution of this Promissory Note, the approval of its shareholders of
the issuance of any such shares to the extent required by applicable law,
Payor's organizational documents or the rules of the Nasdaq Stock Market.


NEMATRON CORPORATION


-----------------------------------
By: Matthew S. Galvez, President


ACCEPTED AND AGREED:


_______________________________________ [Payee]

By: ___________________________________ [Signature]

Name: _________________________________

Its: __________________________________

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