<PAGE>   1

EXHIBIT 10.2 - BANK LINE OF CREDIT AGREEMENT


[NORTHWEST BANK LOGO]                              Norwest Bank Minnesota, N.A.
                                                   7900 Xerxes Avenue South
                                                   MAC N9307-013
                                                   Bloomington, Minnesota 55431
                                                   612/667-0281



March 29, 2000


Mr. Rob Barniskis
Chief Financial Officer
Check Technology Corporation
12500 Whitewater Drive
Minnetonka, MN 55343

Dear Mr. Barniskis:

I am pleased to inform you that Norwest Bank Minnesota, N.A. (the "Bank") has
approved the renewal of a committed line of credit (the "Line") in the amount of
$2,500,000.00 to be offered to Check Technology Corporation (the "Borrower").
The availability of the Line is subject to the Bank's receipt of a new executed
commercial note (the "Note") and our mutual execution of this letter agreement.
The following terms and conditions shall apply to the Line:

Borrower:                     Check Technology Corporation

Amount:                       $2,500,000.00

Type:                         One year, committed line of credit, with maturity
                              date of April 30, 2001.

Purpose:                      To finance working capital needs of the Borrower.

Interest Rate:                Norwest Base Rate, floating.

Prepayments:                  Prepayments of principal may be made at any time
                              by the Borrower without penalty; however, any
                              payments of LIBOR borrowing contracts made prior
                              to the stated contractual maturity of the contract
                              will be subject to reimbursement to the Bank for
                              reasonable redeployment costs.

Collateral:                   Unsecured, however, all current assets of Borrower
                              must remain free of liens or encumbrances.

Facility Fee:                 A facility fee of one-fifth of one percent
                              (20 basis points) per annum computed on a 360-day
                              basis will be applied to the unused portion of the
                              line of credit. This fee shall be paid in arrears
                              at the end of each calendar quarter.



<PAGE>   2



Covenants:                    The Borrower agrees to comply with the following:

                              1.  Preserve its corporate existence along with
                                  all subsidiaries, adequately maintain and
                                  insure its properties. Additionally, the
                                  Borrower will not, nor will it permit any
                                  subsidiary to sell, dispose of, or transfer
                                  away any material portion of its assets or
                                  properties necessary or desirable for the
                                  proper conduct of its business.

                              2.  All corporate assets, including all subsidiary
                                  assets, must be kept free and clear of liens,
                                  except for currently existing liens and
                                  purchase money security interests.

                              3.  The Borrower and each of its subsidiaries must
                                  refrain from issuing a corporate guaranty or
                                  becoming contingently liable in connection
                                  with any obligation of any other person or
                                  entity.

                              4.  On a consolidated basis and in accordance with
                                  GAAP, the financial performance and conditions
                                  of the Borrower must remain within the
                                  following bounds at all times:

                              (a) Total Liabilities to Tangible Net Worth Ratio.
                                  Maintain a ratio of total liabilities to
                                  Tangible Net Worth of less than 0.50 to 1.0
                                  at all times.

                                  "Tangible Net Worth" means total assets less
                                  total liabilities and less the following types
                                  of assets: (1) leasehold improvements; (2)
                                  receivables and other investments in or
                                  amounts due from any shareholder, director,
                                  officer, employee or other person or entity
                                  related to or affiliated with the Borrower;
                                  (3) goodwill, patents, copyrights, mailing
                                  lists, trade names, trademarks, servicing
                                  rights, organizational and franchise costs,
                                  bond underwriting costs and other like assets
                                  properly classified as intangible.

                              (b) Current Ratio.  Maintain a ratio of Current
                                  Assets to Current Liabilities of at least 2.0
                                  to 1.0 at all times.

                                  "Current Assets" means current assets less
                                  receivables and investments in or other
                                  amounts due from any shareholder, director,
                                  officer, employee or any person or entity
                                  related to or affiliated with the Borrower.

                                  "Current Liabilities" means current
                                  liabilities less any portion of such current
                                  liabilities that constitute Subordinated Debt.

                                  "Subordinated Debt" means debt that is
                                  expressly subordinated to the Bank in a
                                  writing acceptable to the Bank.

                              5.  Provide the Bank with annual audited financial
                                  statements within 90 days of the Borrower's
                                  fiscal year end, quarterly financial
                                  statements within 45 days of quarter end, and
                                  quarterly compliance certificates during
                                  periods of borrowing.

                              6.  Promptly notify the Bank upon knowledge of the
                                  occurrence of an event of default hereunder or
                                  under the Note.


                                       2

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                              7.  Supply the Bank with such other information as
                                  the Bank may from time to time reasonable
                                  request, and permit the Bank to have access to
                                  its books, records, properties, and principal
                                  officers as it may reasonably request.

Conditions Precedent:         Borrower shall deliver to the Bank the following
                              documents together with executed copy of this
                              Letter Agreement.

                              1.  A new Commercial Note (the "Note").
                              2.  A new Certificate of Authority to authorize
                                  signers for loans.
                              3.  Prior to making the first advance under the
                                  Line, the Borrower shall deliver a certificate
                                  of compliance for the Borrower's most recent
                                  fiscal quarter.

Default:                      The Bank has the right to not consider any
                              requests for advances under the Line if, as of the
                              date of such request, there exists an event of
                              default under either the Note or this Letter
                              Agreement.  Furthermore, the Bank may declare the
                              Line terminated and declare the unpaid principal,
                              accrued interest and all other amounts payable
                              under the Note to be immediately due and payable,
                              if the Borrower fails in the observance or
                              performance of any covenant or agreement contained
                              herein, and continuance for more than 30 days.  In
                              addition, the Note contains events of default that
                              are incorporated herein by reference.

If the provisions of this Letter Agreement are acceptable, please sign below and
return to me at Norwest.

Sincerely,

/s/ Kent Paulson

Kent Paulson
Relationship Manager

Accepted by:

Check Technology Corporation

By:      /s/  Robert M. Barniskis
   -----------------------------------

Its:       CFO
    ----------------------------------

Date:      31 March 2000
     ---------------------------------


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[NORWEST BANK LOGO]                                             Commercial Note

Borrower's name                                                 Date:
Check Technology Corporation                                    03/29/2000
--------------------------------------------------------------------------------
PROMISE TO PAY: For value received, the undersigned Borrower (if more than one,
jointly and severally) promise(s) to pay to the order of
Norwest Bank Minnesota, National Association                    (the "Bank"), at
--------------------------------------------------------------------------------
7900 Xerxes Avenue South    Bloomington, MN 55431-2209     or at any other place
--------------------------------------------------------------------------------
designated at any time by the holder of this promissory note (the "Note") in
lawful money of the United States of America, the principal sum of Two Million
Five Hundred Thousand and 0/100
--------------------------------------------------------------------------------
Dollars ($ 2,500,000.00 ), together with interest on the unpaid principal amount
        -----------------
in accordance with the repayment terms set forth below.
INTEREST: Interest on this Note, calculated on the basis of actual days elapsed
in a 360 day year, will accrue as follows (choose one of the following):
[x] on the unpaid principal amount of this Note at the Note Rate.

[ ] on the unpaid principal amount of this Note at the              of the Note
                                                       -------------
     Rates selected at any time.

[ ] on the unpaid principal amount of this Note:
     up to and including $              at the Note Rate.
                          -------------
     from $               to and including $              at the Note Rate
            -------------                   -------------                  -----
            %. from $               to and including $              at the Note
     ------           -------------                    -------------
     Rate              %. in excess of $             at the Note Rate
          ----- ------                  -------------                 -----
            %.
     ------
[ ] if the unpaid principal amount of this Note:
     is not in excess of $             at the Note Rate.
                          -------------
     is equal to or greater than $              but not in excess of
                                  -------------
     $              at the Note Rate              %. is equal to or greater than
      -------------                  ----- ------
     $              but not in excess of $              at the Note Rate
      -------------                       -------------                  -----
            %. is equal to or greater than $              at the Note Rate
     ------                                 -------------                  -----
            %.
     ------

NOTE RATE:  The Note Rate under this Note shall be (choose the applicable Note
Rate(s)):
[ ] an annual rate of          % (the "Note Rate"),
                      ---------

[x] an annual rate [x] equal to the Index Rate, or [ ]             %
                                                       -----------   ---------
     the Index Rate, or [ ]           % of the Index Rate, [x] from time
                            ----------
     to time in effect, each change in the interest rate to become effective on
     the day the corresponding change in the Index Rate becomes effective,
     or  [ ]
            --------------------------------------------------------------------
     With an initial interest rate equal to   9.0000 % (the "Note Rate"),
                                            ---------
[ ] an annual rate as set forth in the Interest Rate Addendum attached to this
Note (the "Note Rate"), provided that if this Note has a variable rate of
interest, [ ] the Note Rate shall at no time be less than an annual rate of
             %, and
-------------
[ ] shall at no time exceed an annual rate of           %. In no event shall the
                                              ----------
rate of interest applicable to this Note under any term or condition exceed the
maximum rate permitted by law.
[x] "Index Rate" means [x] the "Base Rate" which is the rate of interest
established by

Norwest Bank Minnesota, National Association    from time to time as its "base"
------------------------------------------------
or "prime" rate, or
[ ] the "Wall Street Rate" which is the highest "prime" rate of
interest reported in the Wall Street Journal "Money Rates" Table, or
[ ] the
       -------------------------------------------------------------------------

       -------------------------------------------------------------------------
REPAYMENT TERMS: Unless payable sooner as a result of its acceleration, the
Borrower promises to pay this Note as follows (choose the applicable Repayment
Term):

  PRINCIPAL.  Principal shall be payable;
  [x] on the earlier of demand or   04/30/2001       (the "Due Date").
                                  ------------------
  [ ] on                         (the "Due Date").
         -----------------------
  INTEREST. Interest shall be payable;
  [ ] on the Due Date.
  [x]  monthly         , commencing 04/30/2000         and on the last day of
      -----------------             ------------------            ----
  each succeeding     month      and on the Due Date.
                  --------------

      Unless applicable law requires the Bank to apply amounts in some other
      manner, all payments shall be applied first in payment of billed interest,
      then to the payment of any outstanding late fees, and the balance thereof
      shall be applied in reduction of the principal amount outstanding,
      provided however, that if an event of default has occurred then all
      payments will be applied as directed by the Bank, in its sole discretion.

  "DUE DATE" means the maturity date of this Note whether it is the stated
maturity date or an earlier date by reason of acceleration or demand.

[x] REVOLVING LINE. The Borrower may borrow, prepay, and reborrow under this
    Note until the Due Date within the limits of this Note, and subject to the
    terms and conditions in any other agreements between the Borrower and the
    Bank.

[ ] CONDITIONAL LINE. Any advances made under this Note shall be at the sole
    discretion of the Bank and the Bank is not obligated to make any advance
    under this Note.

[ ] LATE FEE: Each time that a scheduled payment is not paid when due or within
        days afterwards, the Borrower agrees to pay a late fee equal to [ ]
    ----
    $                    , or [ ]          % of the full amount of the late
     --------------------        ----------
    payment, or [ ] the             of $                    or         % of the
                        ------------    -------------------    --------
    full amount of the late payment. Acceptance by the Bank of any late fee
    shall not constitute a waiver of any default hereunder.

[ ] OTHER FEES: [ ] The Borrower shall pay to the Bank [ ] a nonrefundable,
    one-time Origination Fee equal to $                       and/or [ ] A
                                       ----------------------
   non-refundable, one-time                                      equal to
                            -------------------------------------
    $                     at the time this Note is signed. [ ] The Borrower
     --------------------
    shall pay to the Bank a(n)                            equal to [ ]
                               ---------------------------
    $                 , or [ ]                % per annum (calculated on the
     -----------------         ------ --------
    basis of actual days elapsed in a          day year) of the [ ] average
                                      ---------
    daily unused portion, [ ] maximum principal amount of the line evidenced
    by this Note, payable                       , in              , commencing
                          ----------------------    --------------
                             and on the         day of each succeeding
    ------------------------            --------
                    and on the Due Date.
    ---------------

[ ] ADDITIONAL INTEREST BEFORE AND AFTER THE DUE DATE: Each time that a
scheduled payment is not paid when due or within      days afterward, additional
                                                 ----
interest will begin accruing on the next calendar day on the entire unpaid
principal amount of this Note at an annual rate of          % in excess of the
                                                   ---------
Note Rate ("Additional Interest Rate"). Acceptance by the Bank of Additional
Interest shall not constitute a waiver of any default hereunder. The unpaid
principal and interest due on this Note after the Due Date shall bear interest
until paid at the Additional Interest Rate (except in North Dakota).
PREPAYMENT: The Borrower may at any time prepay this Note, in whole or in part
and any prepayments shall be applied against outstanding principal only after
all billed interest and any outstanding late fees have been paid in full.
SECURITY: In addition to any other collateral interest given to the Bank
previously, now, or in the future, by separate agreements not referenced herein,
which states it is given to secure this Note or all indebtedness of the Borrower
to the Bank, this Note is secured with a(n)
                   dated                      .
-------------------     ----------------------
DEFAULT AND ACCELERATION: Borrower will be default under this Note if:
(i) the Borrower fails to pay when due any principal, interest or other amounts
due under this Note, or (ii) the Borrower fails to perform or observe any term
or covenant of this Note or any related documents or perform under any other
agreement with the Bank, or (iii) the Borrower or any subsidiary fails to
perform or observe any agreement with any other creditor that relates to
indebtedness or contingent liabilities which would allow the maturity of such
indebtedness or obligation to be accelerated, or (iv) the Borrower changes its
legal form of organization, or (v) any representation or warranty made by the
Borrower in applying for the loan evidenced by this Note is untrue in any
material respect, or (vi) a garnishment, levy or writ of attachment, or any
local, state or federal notice of tax lien or levy is served upon the Bank for
the attachment of property of the Borrower or any subsidiary that is in the
Bank's possession or for indebtedness owed

                                       4
<PAGE>   5
to the Borrower or any subsidiary by the Bank, or (vii) any Guaranty given in
connection herewith may have become, in the Bank's judgment, unenforceable, or
(viii) the Bank at any time, in good faith, believes that the Borrower will not
be able to pay this Note when it is due; then or at any time thereafter unless
such default is cured the Bank may, at its option, declare all unpaid principal,
accrued interest, fees and all other amounts payable under this Note to be
immediately due and payable, without notice or demand to the Borrower, and if
this Note evidences a line of credit, terminate the line of credit without
notice to the Borrower. If, however, this Note is payable on demand, nothing
herein contained shall preclude or limit the Bank from demanding payment of this
Note at any time and for any reason, without notice.

AUTOMATIC ACCELERATION: If, with or without the Borrower's consent, a custodian,
trustee or receiver is appointed for any of the Borrower's or any subsidiary's
properties, or if a petition is filed by or against the Borrower or any
subsidiary under the United States Bankruptcy Code, or if the Borrower is
dissolved or liquidated (if an entity), or dies (if an individual), the unpaid
principal, accrued interest and all other amounts payable under this Note will
automatically become due and payable without notice or demand and, if this Note
evidences a line of credit, the line of credit will automatically terminate.

REMEDIES ON DEFAULT: If the indebtedness evidenced hereby is not paid at
maturity, whether by acceleration or otherwise, the Bank shall have all of the
rights and remedies provided by any law and/or by agreement of the Borrower,
including but not limited to all of the rights and remedies of a secured party
under the Uniform Commercial Code. Any requirement of reasonable notice mandated
by the Uniform Commercial Code shall be met if the Bank sends such a notice to
the Borrower at least ten (10) days prior to the date of sale, disposition or
other event giving rise to the required notice. The Borrower shall be liable for
any deficiency remaining after disposition of any property in which the Bank has
a security interest to secure payment of the indebtedness evidenced hereby, and
the computation of such deficiency or of the amount required to redeem such
property shall include, unless otherwise prohibited by law, reasonable
attorney's fees and legal expenses.

WAIVER: Each endorser hereof or any other party liable for the indebtedness
evidenced hereby severally waives demand, presentment, notice of dishonor and
protest of this Note, and consents to any extension or postponement of time of
its payment without limit as to the number or period thereof, to any
substitution, exchange or release of all or any part of any collateral securing
this Note, to the addition of any party hereto, and to the release or discharge
of, or suspension of any rights and remedies against, any person who may be
liable hereon for the payment of the indebtedness evidenced hereby.

AMENDMENT OR MODIFICATION OF TERMS: Any amendment or modification of this Note
must be in writing and signed by the party against whom enforcement of such
amendment or modification is sought. The Bank may change any of the repayment
terms of this Note, including extensions of time and renewals, and release or
add any party liable on this Note, or agree to the substitution or release of
any security collateralizing this Note without notifying or releasing from
liability any accommodation party, endorser, or guarantor. The Bank may suspend
or waive any rights or remedies that it may have against any person who may be
liable for its repayment.

MISCELLANEOUS: No delay on the part of the Bank in the exercise of any right or
remedy shall operate as a waiver thereof, and no single or partial exercise by
the Bank of any right or remedy shall preclude any other future exercise thereof
or the exercise of any other right or remedy. No waver or indulgence by the Bank
of any default shall be effective unless in writing and signed by the Bank, nor
shall a waiver by the Bank on one occasion be construed as a bar to, or waiver
of, any such right on any future occasion. Any reference to the Bank herein
shall be deemed to include any subsequent holder of this Note. This note is
accepted in the state where the Bank is located, and shall be governed by the
laws of the state where the Bank is located. The Borrower agrees to pay all
costs in connection with the borrowing represented by this Note or security
given, including any taxes, stamp, insurance or otherwise, payable by reason of
execution and delivery of this Note and any related documents. In the event the
Bank is required to collect this Note following its Due Date or the bankruptcy
of any maker hereof, the Borrower will pay the Bank such further amounts as
shall be sufficient to cover the costs and expenses incurred in collecting this
Note and liquidating any security or guaranties given in support hereof,
including reasonable attorney's fees and expenses required to take such actions
in any court, including any bankruptcy court.

FINANCIAL REPORTING: While any amounts are due under this Note, or the Borrower
has the right to request an advance under this Note, the Bank reserves the right
to require that the Borrower deliver to the Bank annual financial statements and
such other financial information as the Bank may request.

ARBITRATION: The Bank and Borrower agree, at the request of either party, to
submit to binding arbitration all claims, disputes and controversies whether in
tort, contract, or otherwise, except "core proceedings" under the U.S.
Bankruptcy Code arising between themselves and their respective employees,
officers, directors, attorneys, and other agents, which relate in any way
without limitation to this Note, including by way of example but not by way of
limitation the negotiation, collateralization, administration, repayment,
modification, default, termination and enforcement of the loans or credit
evidenced by this Note. Arbitration under this Agreement will be governed by the
Federal Arbitration Act (Title 9 of the United States Code), except in Colorado
where it will be governed by Colorado law, and proceed in the city where the
Bank's principal office is located, or such other location as the Bank and
Borrower may agree and shall be conducted by the American Arbitration
Association ("AAA") in accordance with the AAA's commercial arbitration rules
("AAA Rules"). Arbitration will be conducted before a single neutral arbitrator
selected in accordance with AAA Rules and who shall be an attorney who has
practiced commercial law for at least ten years. The arbitrator will determine
whether an issue is arbitratable and will give effect to applicable statutes of
limitation. Judgment upon the arbitrator's award may be entered in any court
having jurisdiction. The arbitrator has the discretion to decide, upon documents
only or with a hearing, any motion to dismiss for failure to state a claim or
any motion for summary judgment. The institution and maintenance of an action
for judicial relief or pursuit of a provisional or ancillary remedy shall not
constitute a waiver of the right of any party, including the plaintiff, to
submit the controversy or claim to arbitration if any other party contests such
action for judicial relief. The arbitrator will award costs and expenses in
accordance with the provisions of this Note. Discovery will be governed by the
rules of civil procedure in effect in the state where the Bank's principal
office is located. Discovery must be completed at least 20 days before the
hearing date and within 180 days of the commencement of arbitration. Each
request for an extension and all other discovery disputes will be determined by
the arbitrator upon a showing that the request is essential for the party's
presentation and that no alternative means for obtaining information are
available during the initial discovery period. This Agreement does not limit the
right of either part to (i) foreclose against real or personal property
collateral; (ii) exercise self-help remedies such as setoff or repossession; or
(iii) obtain provisional remedies such as replevin, injunctive relief,
attachment or the appointment of a receiver during the pendency or before or
after any arbitration proceeding. These exceptions do not constitute a waiver of
the right or obligation of either party to submit any dispute to arbitration,
including those arising from the exercise of these remedies.

STATE LAW REQUIREMENTS:
If the Bank is located in IOWA: IMPORTANT: READ BEFORE SIGNING. THE TERMS OF
THIS NOTE AND AGREEMENT SHOULD BE READ CAREFULLY BECAUSE ONLY THOSE TERMS IN
WRITING ARE ENFORCEABLE. NO OTHER TERMS OR ORAL PROMISES NOT CONTAINED IN THIS
WRITTEN CONTRACT MAY BE LEGALLY ENFORCED. YOU MAY CHANGE THE TERMS OF THIS NOTE
AND AGREEMENT ONLY BY ANOTHER WRITTEN AGREEMENT. THIS NOTICE ALSO APPLIES TO ANY
OTHER CREDIT AGREEMENTS (EXCEPT CONSUMER LOANS OR OTHER EXEMPT TRANSACTIONS) NOW
IN EFFECT BETWEEN YOU AND THIS LENDER. BY SIGNING THIS NOTE AND AGREEMENT, THE
BORROWER ACKNOWLEDGES RECEIPT OF A COPY OF THIS NOTE AND AGREEMENT.

If the Bank is located in MINNESOTA: This extension of credit is made under: (i)
Minn. Stat.ss.47.204 if this Note is from an individual and is secured by a
first lien on residential real estate; (ii) Minn. Stat.ss.334.01, subd. 2, if
the initial advance under this Note is $100,000.00 or more and it is not secured
by a first lien on residential real estate.

If the Bank is located in NEBRASKA: A credit agreement must be in writing to be
enforceable under law. To protect you and us from any misunderstandings or
disappointments, any contract, promise, undertaking or offer to forebear
repayment of money or to make any other financial accommodation in connection
with this loan of money or grant or extension of credit, or any amendment of,
cancellation of, waiver of, or substitution for any or all of the terms or
provisions of any instrument or document executed in connection with this loan
of money or grant or extension of credit, must be in writing to be effective.

If the Bank is located in TEXAS: THIS WRITTEN LOAN AGREEMENT REPRESENTS THE
FINAL AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF
PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE
NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES. CHAPTER 346 OF THE TEXAS
FINANCE CODE OR ANY SUCCESSOR STATUTE WHICH REGULATE CERTAIN REVOLVING LOAN
ACCOUNTS SHALL NOT APPLY TO THIS AGREEMENT.

If the Bank is located in NORTH DAKOTA: In all events the Note Rate shall be the
same rate after the Due Date as was in effect on the Due Date. If this Note is
secured by a mortgage on real property located in North Dakota except a first
mortgage: THIS OBLIGATION MAY BE THE BASIS FOR A PERSONAL ACTION AGAINST THE
PROMISOR OR PROMISORS IN ADDITION TO THE OTHER REMEDIES ALLOWED BY LAW. (The
term "Promisor" or "Promisors" means the Borrower herein.) If the Note is
secured by a mortgage on commercial real property located in North Dakota, the
Bank has the right, following an event of default, to proceed to obtain and
collect a deficiency judgment, together with foreclosure of the real property
mortgaged under applicable laws.

--------------------------------------------------------------------------------
SIGNATURES
--------------------------------------------------------------------------------
Borrower's Name
     Check Technology Corporation
--------------------------------------------------------------------------------
Signature                                       Signature
x  /s/ Robert M. Barniskis                      x
--------------------------------------------------------------------------------
Name and Title (if applicable)                  Name and Title (if applicable)
    /w/ Robert M. Barniskis
    /w/ Chief Financial Officer
--------------------------------------------------------------------------------
Signature                                       Signature
x                                               x
--------------------------------------------------------------------------------

Name and Title (if applicable)                  Name and Title (if applicable)

--------------------------------------------------------------------------------
Street address                                  City, State, Zip code
12500 Whitewater Drive                          Minnetonka, MN 55343-9420
--------------------------------------------------------------------------------

Loan Purpose: [x] Business      , and/or [ ] this Note is given as replacement
                  --------------
for, and not in satisfaction of the promissory note given by the Borrower to the
Bank dated                          .
           -------------------------

                                       5