Document:

<PAGE>
                                                                    EXHIBIT 10.F

                                 PROMISSORY NOTE

                                                             Dated: May 12, 1997

            ON DEMAND, FOR VALUE RECEIVED, the undersigned, NAPCO Security
Systems, Inc. (the "Company"), a corporation formed under the laws of the State
of Delaware, having its principal office located at 333 Bayview Avenue,
Amityville, New York 11701, hereby promises to pay to the order of MARINE
MIDLAND BANK (the "Bank") at its office at 534 Broad Hollow Road, Melville, New
York 11747, or at such other place as the holder of this Promissory Note may
from time to time designate in writing, in lawful money of the United States and
in immediately available funds, the principal sum of TWO MILLION FIVE HUNDRED
THOUSAND AND 00/100 ($2,500,000) DOLLARS, or so much as may be drawn on the
Letter of Credit (as defined in the Reimbursement Agreement [hereinafter
defined]) and such other amounts as may be owed to the Bank pursuant to the Loan
Documents (as defined in the Reimbursement Agreement) including, but not limited
to, the Bank's reasonable attorney's fees upon the occurrence of an Event of
Default under the Reimbursement Agreement together with interest on the
principal amount remaining unpaid hereunder from time to time from the date of
any draw on the Letter of Credit until such principal amount has been paid in
full. Any amount owed the Bank pursuant to this Promissory Note shall bear
interest at a rate per annum equal to the Prime Rate plus three (3%) percent per
annum in accordance with the terms herein and as set forth in the Reimbursement
Agreement.

            The interest rate shall be adjusted, without notice, as of the
effective date of any change in the Prime Rate and shall be computed hereunder
on the basis of a 360 day year for the actual number of days elapsed. "Prime
Rate" shall mean that floating rate of interest per annum announced by the Bank
from time to time as being the Bank's prime rate, which is a base for
calculating interest on certain loans.

            In no event shall the interest rate and charges herein or in the
Reimbursement Agreement or other Loan Documents, exceed the highest rate
permissible under any law which a court of competent jurisdiction shall, in a
final determination, deem applicable hereto. In the event that a court
determines that the Bank has received interest and other charges in excess of
the highest rate applicable hereto, such excess shall be deemed received on
account of, and shall automatically be applied to reduce the obligations arising
under or in connection with this Promissory Note other than interest, and the
provisions hereof shall be deemed amended to provide for the highest permissible
rate. If there is no indebtedness outstanding, the Bank shall refund such excess
to the Borrower.

            Capitalized words and phrases not otherwise defined herein shall
have the meanings ascribed to such terms in the standby letter of credit
application and reimbursement agreement by and between the Company and the Bank
dated as of May 12, 1997 (the "Reimbursement Agreement").

            Notwithstanding the foregoing, this Promissory Note is also intended
to evidence the

                                      E-79

<PAGE>
Letter of Credit fees, commissions and expenses of the Company to the Bank and
any and all charges and expenses which the Bank may pay or incur relative to the
draw on the Letter of Credit.

            This Promissory Note is the Promissory Note (or Note) referred to in
the Reimbursement Agreement and shall be entitled to the benefit of all security
granted in the Loan Documents and all benefits thereof. The Loan Documents,
among other things, contain provisions for payment of fees, charges and expenses
and regarding the remedies of the Bank upon the occurrence of an Event of
Default. The Loan Documents also contain representations, warranties, covenants
and conditions, all of which are hereby made part of this Promissory Note to the
same extent and with the same effect as if set forth herein at length. Without
limiting the foregoing, this Promissory Note is secured by and the parties
hereto are entitled to the benefits of that certain mortgage and security
agreement, dated of even date herewith (the "Mortgage"), made by the Company to
the Bank, encumbering, among other things, certain real property and
improvements now or hereafter located on said real property, situate at 359
Bayview Avenue, a\k\a 333 Bayview Avenue, Amityville, New York 11701 in the Town
of Babylon, County of Suffolk, State of New York, as more particularly described
in the Mortgage ("Mortgaged Premises" or "Mortgaged Property"), and is executed
and delivered pursuant to the Reimbursement Agreement, all of the covenants,
conditions and agreements of the Mortgage and the Reimbursement Agreement being
made a part hereof by this reference.

            The holder of this Promissory Note at its option may extend the time
for payment of this Promissory Note, postpone the enforcement hereof, or grant
any other indulgences, without affecting or diminishing the holder's right to
recourse against the Company or any endorsers, sureties or guarantors, which
right is expressly reserved.

            The Company and any endorsers, sureties and guarantors of this
Promissory Note waive presentment for payment, demand, protest, notice of
protest and notice of dishonor hereof, and, except as expressly set forth in the
other Bank Documents, all other notices to which they may be entitled.

            The terms and provisions hereof shall inure to the benefit of the
Bank, and its successors and assigns and shall be binding upon the respective
successors and assigns of the Company.

            In the event the Bank, for any reason whatsoever, shall deem it
necessary to refer this Promissory Note to an attorney for the enforcement
thereof or any rights thereunder, by suit or

                                        2

                                      E-80

<PAGE>
otherwise or for the protection or preservation of any rights hereunder, there
shall be due and owing reasonable attorneys' fees, together with all costs and
expenses of any such action, and the Bank may take judgment for all such
amounts.

            This Promissory Note and the rights and obligations of the parties
hereunder shall be governed and construed in accordance with the laws of the
State of New York.

            The Company agrees that any action or proceeding to enforce this
Promissory Note or arising out of or related to this Promissory Note may be
commenced in any State court of competent jurisdiction in Nassau, Suffolk or
Kings County, New York, or in the United States District Court for the Eastern
District of New York, and the Company consents and submits in advance to such
jurisdiction and agrees that venue shall be proper in such courts on any such
matter.

            The Company acknowledges that this Promissory Note is and shall be
effective upon its execution by the Company and delivery hereof to the Bank and
it shall not be necessary for the Bank to execute any acceptance hereto or to
otherwise signify or express its acceptance hereof.

            THE COMPANY AGREES THAT ANY LITIGATION GROWING OUT OF ANY
CONTROVERSY WITH RESPECT TO, IN CONNECTION WITH OR ARISING OUT OF THIS
PROMISSORY NOTE, THE AGREEMENT OR ANY INSTRUMENT OR DOCUMENT DELIVERED PURSUANT
HERETO AND THERETO WILL BE TRIED BY A COURT BY A JUDGE SITTING WITHOUT A JURY.
THE COMPANY CONFIRMS THAT THE FOREGOING WAIVER OF A TRIAL BY JURY IS INFORMED
AND FREELY MADE.

                                        3

                                      E-81

<PAGE>
            IN WITNESS WHEREOF, the Company has caused this Promissory Note to
be executed by it by its officer on the date first written above.

                              NAPCO Security Systems, Inc.

                        By:  /s/
                             -----------------------------------
                             Kevin Buchel
                             Senior Vice President

                                        4

                                      E-82<PAGE>
                                                                    EXHIBIT 10.G

               AMENDMENT NO. 1 TO THE LOAN AND SECURITY AGREEMENT

         AMENDMENT NO. 1 to the Loan and Security Agreement dated as of May 28,
1998 ("Amendment No. 1") by and between NAPCO SECURITY SYSTEMS, INC., a New York
corporation having a place of business at 333 Bayview Avenue, Amityville, New
York 11701 (the "Debtor") and Marine Midland Bank, having a place of business at
534 Broad Hollow Road, Melville, New York 11747 (the "Secured Party").

                              W I T N E S S E T H :

         WHEREAS, as of May 12, 1997, Debtor and Secured Party had entered into
a certain loan and security agreement, as further amended from time to time (the
"Agreement");

         WHEREAS, the Debtor has requested that the Secured Party advance the
sum of $2,500,000.00 pursuant to the terms of the Term Loan Note (as hereinafter
defined) and the Secured Party has agreed to do so, in the manner set forth
below, provided however, that, among other things, Debtor execute this Amendment
No. 1.

         NOW, THEREFORE, in consideration of the mutual promises and for other
good and valuable consideration, the receipt of which is hereby acknowledged,
the parties hereto agree as follows:

         1. The definition of "Transaction Documents" contained in Section 1.1.
of the Agreement is hereby amended to read in its entirety as follows:

         "Transaction Documents" shall mean, individually, jointly, severally
         and collectively, the Agreement (including this Amendment No. 1) and
         all documents, including, without limitation, the Term Loan Note,
         collateral documents, letter of credit agreements, notes, acceptance
         credit agreements, security agreements, pledges, guaranties, mortgages,
         title insurance, assignments, and subordination agreements required to
         be executed by Debtor, any Third Party, or any Responsible Party
         pursuant hereto or in connection herewith, in connection with the
         issuance of a certain standby letter of credit in the amount not to
         exceed $2,500,000.00 by Secured Party in favor of Citibank, N.A., at
         the request of and for the benefit of Debtor, the reimbursement
         obligations being evidenced by a promissory note in the principal sum
         not to exceed $2,500,000.00, and a letter of credit application and
         reimbursement agreement, each dated as of May 12, 1997, and a certain
         uncommitted trade line established by Marine in favor of Debtor to
         provide for commercial and standby letters of credit, evidenced by,
         among other documents, a continuing letter of credit agreement, and a
         continuing indemnity agreement, each dated as of May 12, 1997, and the
         Term Loan Note in the principal sum of $2,500,000.00, and all other
         documents, agreements, reaffirmations, certificates and resolutions
         related thereto, and amendments or supplements thereto, all such other
         agreements, resolutions, certificates, resolutions and opinion letters
         executed and/or issued as a condition precedent to or in connection
         with the Agreement, the Term Loan Note and all such other documents,
         agreements, and instruments delivered hereunder or as a supplement or
         amendment thereto or as Secured Party may reasonably

                                      E-83

<PAGE>
         require from time to time in order to evidence and/or secure the
         indebtedness of Debtor to Secured Party or to create, perfect, continue
         the perfection or protect the Secured Party's security interest in the
         Collateral.

         2. The definition "Term Loan" shall be added to Section 1.1. of the
Agreement and shall read as follows:

         "Term Loan" shall mean the $2,500,000.00 term loan made available to
         Debtor to Secured Party pursuant to the Term Loan Note.

         3. The definition of "Term Loan Note" shall be added to Section 1.1. of
the Agreement and shall read as follows:

         "1998 Term Loan Note" shall mean the $2,500,000.00 note evidencing the
         Term Loan executed by Debtor and delivered to Secured Party as of even
         date hereof; Debtor has used or will use the proceeds of the Term Loan
         Note to finance the purchase by Debtor of 889,576 shares of Debtor's
         common stock, $.01 par value, owned by Kenneth Rosenberg, pursuant to a
         certain stock purchase agreement dated as of even date hereof by and
         between Kenneth Rosenberg and the Corporation (the "Stock Purchase
         Agreement").

         4. New Sections 4.26. and 4.27 are added as follows:

                  Section 4.26. Stock Purchase Agreement, etc.

                  Debtor has heretofore delivered to Secured Party true and
         complete copies of the Stock Purchase Agreement, the promissory note in
         the principal sum of $1,947,880.00, executed by Debtor in favor of
         Kenneth Rosenberg, and all other agreements and documents by and
         between Debtor and Kenneth Rosenberg or by Debtor in favor of Kenneth
         Rosenberg, including all amendments thereof. Debtor represents and
         warrants to Secured Party that it has disclosed in writing all of the
         terms of the purchase by Debtor of 889,576 shares of the Debtor's
         common stock, $.01 par value, owned by Kenneth Rosenberg, and any other
         ancillary transactions by and between Debtor and Kenneth Rosenberg in
         connection therewith.

                  Section 4.27. Term Loan Note Proceeds

         The proceeds of the Term Loan shall be used by Debtor to finance the
         purchase by Debtor of 889,576 shares of Debtor's common stock, $.01 par
         value, owned by Kenneth Rosenberg, pursuant to the Stock Purchase
         Agreement.

         5. Section 9.26. of the Agreement shall be deleted in its entirety
replaced with the following:

                  9.26. FINANCIAL COVENANTS. The financial covenants to include
                  the following:

                  (a) Debtor and its Consolidated Subsidiaries shall maintain,
                  on a consolidated basis, a ratio of Total Liabilities to
                  Tangible Net Worth of not greater than (to be tested quarterly
                  based upon the financial statements required to be presented
                  to Secured Party pursuant to Section 9.1.):

                                      E-84

<PAGE>
                  (i) during the period commencing as of the date hereof through
                  June 29, 1999, 1.35 to 1.0,

                  (ii) during the period commencing on June 30, 1999 through
                  June 29, 2000, 1.25 to 1, and

                  (iii) during the period commencing on June 30, 2000 through
                  June 29, 2001, and thereafter while any Indebtedness remains
                  outstanding, 1.10 to 1.

                  (b) Debtor and its Consolidated Subsidiaries shall maintain,
                  at fiscal year end June 30, 1998, on a consolidated basis, a
                  minimum Tangible Net Worth of not less than $25,400,000.00,
                  and at each fiscal year end thereafter, the required minimum
                  Tangible Net Worth shall increase by $1,000,000.00 per fiscal
                  year; to be tested each fiscal quarter end of each fiscal
                  year, based upon the financial statements required to be
                  presented to Secured Party pursuant to Section 9.1.
                  hereinabove.

                  (c) At all times, Debtor and its Consolidated Subsidiaries
                  shall maintain, on a consolidated basis, a ratio of Current
                  Assets to Current Liabilities (i) of not less than 2.75 to 1
                  from the date hereof through June 29, 1998, (ii) of not less
                  than 3.00 to 1 from June 30, 1998 through June 29, 1999, (iii)
                  of not less than 3.25 to 1 from June 30, 1999 through June 29,
                  2000 and beyond, to be tested each fiscal quarter end of each
                  fiscal year, based upon the financial statements required to
                  be presented to Secured Party pursuant to Section 9.1.
                  hereinabove.

                  (d) Debtor and its Consolidated Subsidiaries shall maintain,
                  on a consolidated basis, a minimum "Debt Service Coverage
                  Ratio" of 1.25 to 1, to be tested at the end of each fiscal
                  year, based upon the financial statements required to be
                  presented to Secured Party pursuant to Section 9.1.
                  hereinabove.

                  (e) At all times during the Loan Period, Debtor and its
                  Consolidated Subsidiaries shall maintain, on a consolidated
                  basis, a ratio of the aggregate of cash plus total Receivables
                  to Current Liabilities of not less than 1.25 to 1 from the
                  date hereof until all indebtedness owed to Secured Party is
                  paid in full, to be tested each fiscal quarter of each fiscal
                  year, based upon the financial statements required to be
                  presented to Secured Party pursuant to Section 9.1.
                  hereinabove.

                  The above ratios of this Section 9.26. are being calculated
                  assuming that in the last year of the Loan Agreement, the
                  Advances under the Revolving Credit Facility are viewed as
                  long-term debt, unless there is an event of default which is
                  continuing under the Revolving Credit Facility.

         6. As an inducement to the Bank extending the Term Loan, and modifying
the provisions of the Agreement pursuant to the terms herein, Debtor represents

                                      E-85

<PAGE>
and warrants to Secured Party that, as of the date of execution of this
Amendment No. 1, (i) the representations and warranties set forth in Article 4
of the Agreement and the representations and warranties of Debtor and any Third
Party set forth in the other Transaction Documents to which any is a party are
true and correct in all respects, (ii) no event has occurred and is continuing
which constitutes an "Event of Default" under any of the Transaction Documents
(as "Event of Default" is defined in each of those Transaction Documents), and
(iii) Debtor is in compliance with the covenants set forth in Articles 9 and 10
of the Agreement.

         7. Debtor represents and warrants to Secured Party that there are no
offsets, defenses or counterclaims to the payment of the indebtedness owing
Secured Party, including the Advances, and to the continuing general security
interest in the Collateral granted to Secured Party by Debtor as security for
payment of the indebtedness, as fully described in the Agreement.

         8. Except as modified herein, all other provisions of the Agreement and
the other Transaction Documents remain unmodified and are in full force and
effect.

         18. This Amendment No. 1 shall be governed by the laws of the
State of
New York.

IN WITNESS WHEREOF, the parties have executed this Amendment No. 1 as of the day
and year first above written.

WITNESS:                                            MARINE MIDLAND BANK

________________________                     By:    /s/ JAMES P. JOHNIS
                                                    James P. Johnis
                                                    Vice President

WITNESS:                                            NAPCO SECURITY
SYSTEMS, INC.

_________________________                    By:    /s/ KEVIN BUCHEL
                                                    Kevin Buchel
                                                    Senior Vice President

                                      E-86

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00072-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00072-of-00352.parquet"}]]