PART-TIME EMPLOYMENT, NON-COMPETITION, DISABILITY, AND RETIREMENT AGREEMENT

      AGREEMENT made as of the 1st day of June, 1999, between David B.
Lederer ("Executive") and Detection Systems, Inc., a New York corporation
("Company").

                                 WITNESSETH:
      In consideration of the mutual covenants contained herein, the
parties agree as follows:

            1.    Effectiveness and Terms.  This Agreement shall be binding
on the parties as of its date set forth above (the "Commencement Date"
herein).  "Term of Employment" as used herein shall mean the period
commencing on the Commencement Date and continuing thereafter through
December 31 of the year in which Executive's 69th birthday occurs, unless
the Company and Executive agree in writing to extend the Term of
Employment, in which case the Term of Employment shall have the meaning as
determined at that time; provided, however, that Executive's employment
services may be earlier terminated as hereinafter expressly set forth or as
may be agreed between Executive and the Company, in which event the Term of
Employment shall mean the period from the Commencement Date through the
date of such earlier termination (but such a termination shall not affect
Executive's obligation to provide minimum consulting services as provided
in Section 5 below).

      2.    Non-Competition.  During any period (a) in which Executive is
being paid currently for employment services as provided in Section 4
below, (b) in which Executive is being paid currently the compensation
called for by Section 3 below, (c) in which Executive is being paid
currently for disability benefits as provided under Section 11 below, or
(d) in which Executive is being paid currently for retirement benefits as
provided under Section 9 or 10 below, Executive shall not, without the
prior written consent of the Board of Directors of the Company, engage, as
an employee, partner, consultant, venturer, entrepreneur, or otherwise, in
the development or sale of any product or service which is competitive with
any product or service sold or under active development by the Company
during the Term of Employment.

      3.    Compensation for Non-Competition.  After the Term of Employment
has ended, in consideration for Executive's non-competition as provided in
Section 2 above, the Company shall pay and provide to Executive the
following compensation and benefits through December 31 of the year in
which Executive attains the age of 69:
      (a)   An annual non-competition fee equal to or greater than
$123,600, that fee to be increased each year if and to the extent the CPI
(defined below) has increased during the preceding year (and any fees
earned as a director of the Company shall be credited to that fee), which
fee shall be paid in full on January 2 of each year;
      (b)   The Executive will not participate in any of the Company's
executive incentive compensation plans except for any such plan or plans
which expressly refer to this Agreement;
      (c)   Grants of options under any Company stock option plan that
permits such options, in such amounts as are determined by the Board of
Directors or the Committee of the Board administering the plan;
      (d)   Participation in Company pension, deferred compensation,
insurance, health and welfare and other benefit plans in effect on the date
of this Agreement; and
      (e)   Continuation of all plans in which the Executive participates,
including existing fringe benefits and executive perquisites to which
Executive is entitled as of the date immediately prior to the Commencement
Date under this Agreement.
      Beginning on the January 1 after the year in which Executive attains
the age of 69, the retirement benefits set forth in Sections 9 and 10 below
shall be the full consideration to be paid to Executive for his
non-competition.

      4.    Employment.  The Company hereby employs Executive in the
capacity of Vice President, Business Development for the Term of Employment
commencing on the Commencement Date.  The Company agrees to provide
Executive with such offices and such operational and administrative support
as is consistent with his position and responsibilities under this
Agreement.  The compensation and benefits which the Company shall provide
Executive for his services during the Term of Employment shall include, but
not be limited to, (a) base salary equal to or greater than $134,195
(including directors fees, if applicable) and (b) the benefits listed in
clauses (b), (c), (d), and (e) of Section 3 above.  Executive agrees that
he will devote approximately half time and his best efforts during
reasonable business hours to performance of the duties and responsibilities
of his office during the Term of Employment.  Executive also agrees not to
disclose trade secrets of the Company, or to engage in any other activity
which is detrimental to the interests of the Company, during the Term of
Employment.

      Notwithstanding any of the other provisions of this Agreement, the
Term of Employment will automatically terminate upon Executive's death and
thereupon all payments and non-vested benefits payable hereunder and under
Section 3 above shall cease, except for any death benefits and any survivor
benefits for his spouse which are provided under the Company's employee
plans and except for the retirement benefits set forth in Section 9 for any
surviving spouse.  Those retirement benefits shall be paid pursuant to
Section 9 commencing after Executive's 69th birthday would have occurred,
except that the surviving spouse may elect, by written notice given to the
Company's President or Secretary, to receive early retirement benefits as
provided in Section 10 below, in which case the provisions of Section 9
below shall apply, except that the initial retirement wage benefit shall be
calculated as provided in Section 10.

      The Company may terminate Executive's services due to Executive's
permanent disability, as determined by the Board of Directors in good faith
based on the certification of an independent M.D., and thereupon all
payments and non-vested benefits under this Section 4 and under Section 3
shall cease except that the disability and retirement benefits shall be
paid in accordance with the provisions of Sections 9, 10, and 11 below.

      5.    Minimum Consulting Services.  After a termination of
Executive's services pursuant to Section 7, 8, or 9 below, the Company shall
nevertheless have the right to call upon Executive, so long as Executive is
able, for up to 8 days of consulting services per year to provide
information concerning matters that occurred, were developed, or were
determined while Executive was a full-time or part-time employee of the
Company.  Unless otherwise agreed, these consulting services shall be
rendered at a place and time mutually agreed (but within 25 miles of
Executive's residence at the time) and shall be paid at the rate of $1,200
per day (or up to 100 hours of consulting services per year at an hourly
rate to be agreed upon).  Any other consulting services shall be provided
if, as, and when the parties may agree.

      6.    Executive's Acceptance.  Executive agrees to provide the
employment and the consulting services described in this Agreement.

      7.    Termination for Cause.  The Company may terminate Executive's
services immediately and without prior notice to Executive for "Cause" as
defined below.  The existence of Cause shall be determined by the Company's
Board of Directors (other than Executive) acting in good faith.  "Cause" is
defined, and shall be limited to, a good faith determination by the Board
of Directors that any of the following has occurred:

      (a)   Executive has knowingly misappropriated for his benefit a
material amount of funds or property of the Company;

      (b)   Executive has obtained a material personal profit from any
illegal Company transaction with a third party;

      (c)   Executive has obtained a material personal profit from the use
of the Company's trade secrets other than on its behalf; or

      (d)   The Company has suffered material financial harm from knowingly
illegal action by Executive other than on the Company's behalf or for its
benefit.

      If Executive's services are terminated by the Company for Cause, he
shall continue to be paid compensation and benefits for his non-competition
in accordance with the provisions of Section 3 above, for any minimum
consulting services provided pursuant to Section 5 above, and retirement
benefits in accordance with Section 9 and, if elected, Section 10 below,
provided that his cash compensation (including retirement benefit payments
to be provided under this Agreement) shall be reduced by the amount of any
monetary damage suffered by the Company due to the Cause, as determined by
a court of competent jurisdiction, prorated over the actuarially determined
term of all such payments beginning on such determination.

      8.    Resignation.  If, at any time prior to Executive's retirement
as provided in Section 9 below, Karl H. Kostusiak is no longer employed as
the full time senior executive officer of the Company, Executive shall have
the option of resigning from his employment obligations under Section 4 of
this Agreement by giving written notice thereof to the Company's President
or Secretary, but no resignation shall affect Executive's obligation to
provide the minimum consulting services provided for in Section 5 above.

      9.    Retirement.  The Company hereby agrees that, if not ended
sooner, the Term of Employment as used in this Agreement shall end at the
close of business on December 31 of the year in which Executive attains the
age of 69, and beginning on the opening of business on January 1 of the
next year (and regardless whether the Term of Employment ended prior to
that December 31), the Company will pay Executive retirement benefits for
his lifetime and for his spouse's lifetime, if his spouse survives him, as
follows:

      (a)   a retirement wage benefit initially equal to 30% of the base
salary rate being paid to Executive at the end of his full time employment
with the Company, increased for each year after the end of his full time
employment by any increase in the CPI (as defined below), except that the
retirement wage benefit shall be equal to 60% of that base salary rate at
the end of Executive's full time employment with the Company, plus CPI
increases, effective for any retirement year after a Change in Control and
after the conditions described in Section 20(b)(ii) below have occurred
which would allow Executive to give the notice described there
(disregarding his retirement, if any), and except that the retirement wage
benefit for his spouse shall be 75% of the amount thus calculated for each
year after the year of Executive's death;

      (b)   continuation of Executive's participation (for himself and his
spouse) in the health program in effect on the date of this Agreement
(including for dental and eye care coverage, an annual physical
examination, and similar benefits); and

     (c)   continuation of all other benefits provided at time of retirement,
            such continuation limited in individual benefit cost to 60% of
            the maximum annual cost of such benefit in any year prior to
            retirement, plus CPI increases,

      For these purposes:

            (1)   unless otherwise agreed or directed by law or a court,
"spouse" shall mean the person to whom Executive is married at the time any
benefit is to be paid, or, after Executive's death, the person to whom
Executive was married at the time of his death;

            (2)   "CPI" shall mean the Consumer Price Index, all Urban Wage
Earners as determined by the United States Department of Labor, Bureau of
Labor Statistics, or any successor governmental agency or, lacking any such
successor, any other authoritative source designated in good faith by the
Board of Directors; and the wage benefit shall be increased as of January 1
each year by multiplying the wage benefit paid during the previous year by
any fraction greater than one calculated by dividing the CPI most recently
computed and available at the end of that previous year by the CPI most
recently computed and available at the end of the year previous to that;
the CPI shall not be used to decrease the wage benefit.

      The parties agree: (x) that the foregoing retirement benefits are in
addition to any other retirement benefits that may be available to
Executive (such as the Company's 401(k) savings plan), (y) that payment of
these retirement benefits may be terminated if a court of law determines
that Executive has violated the provisions of Section 2 above, and (z) that
the Company will purchase and maintain life insurance sufficient to fund
the estimated benefits for Executive's spouse (estimated no later than
Executive's retirement date; any excess policy proceeds to be available, if
agreed, to purchase shares of the Company's Common Stock held in
Executive's estate) and the policy or policies of such insurance shall be
held in trust designated for this purpose.

      (d)   The retirement benefits provided under this Section 9 (and, if
applicable, Section 10) shall be paid as provided herein regardless whether
the Company has any claims against Executive for default under this
Agreement or for any other breach of duty or otherwise, and, except as
otherwise provided in Section 7 above, the Company shall pay those
retirement benefits as provided and must pursue remedies for any such
default or other breach of duty or other claim separately and independently.

      10.  Early Retirement Benefits.  The parties agree that, in the
circumstances expressly provided in this Agreement, Executive and/or
Executive's spouse shall be paid early retirement benefits in accordance
with the following:

      (a)  The provisions of Section 9 shall apply to Executive's and the
spouse's retirement benefits as provided therein, except as expressly
modified by this Section 10, and shall be paid beginning at the time
payment of the early retirement benefits actually commences as provided in
this Agreement;

      (b)  The initial retirement wage benefit shall not be the amount set
forth in Section 9(a) above, but shall be calculated as follows:  multiply
the initial retirement wage benefit (calculated in accordance with Section
9(a) above) by the actuarially determined number of years it would be paid
during Executive's then actuarially determined remaining lifespan as if
Executive's 69th birthday had just occurred; then divide that amount by the
number of years then actuarially determined to be Executive's actual
expected remaining lifespan based on his actual age at that time.  The
amount thus calculated shall be the initial annual retirement wage benefit
for purposes of Section 9(a) above.

      11.  Disability.  If Executive is determined to be permanently
disabled in accordance with the provisions of Section 4 above, Executive
shall be paid disability benefits from that date through December 31 of the
year in which Executive attains the age of 69, which disability benefits
shall be equal to the non-competition compensation and benefits and the
salary that would have been paid to Executive pursuant to Sections 3 and 4
above if he had not become disabled, provided that, to the extent the
disability wage benefits are not taxable income to Executive under the U.S.
Internal Revenue Code of 1986, as amended, the disability benefit amount
shall equal 60% of the compensation and salary that would have been paid
pursuant to Sections 3 and 4 above.

      12.  Stock Transfers by Executive and Executive's Estate and Heirs.
So long as this Agreement is in effect, Executive shall not sell any shares
of Company Common Stock except (a) in transactions approved in advance by
the Company's Board of Directors or (b) pursuant to all the conditions of
Rule 144 promulgated by the Securities and Exchange Commission under the
Securities Act of 1933, as amended (or any rule thus promulgated which is a
successor to Rule 144); provided, however, that no such sales shall be made
in any block trade or when there is any plan, program, or tender offer
announced by any person other than the Company to acquire shares of the
Company's Common Stock and that person was required to file a statement,
schedule, or other report with respect thereto with the U.S. Securities and
Exchange Commission under Section 13 or 14 of the Securities Exchange Act
of 1934, as amended, or the rules and regulations thereunder.  Executive
agrees that restrictive legends referring to the provisions of this Section
12 shall be placed upon all certificates representing shares to which this
Section 12 applies.  The provisions of this Section 12 shall terminate upon
any Change in Control or Executive's death, whichever may first occur and
shall not apply thereafter.

      13.   Expenses and Interest.  If the Company is found by a court of
competent jurisdiction to have breached this Agreement, the Company shall
pay the costs and expenses (including reasonable attorneys fees and related
expenses) incurred by Executive in any litigation seeking damages in
respect of such breach or to enforce the performance of this Agreement by
Company, together with interest on each installment of wages or benefits
paid late by the Company calculated to the date of actual payment at an
annual rate equal to 3% over the highest rate then paid by the Company
under its short term borrowing arrangements with an independent
institutional lender (and if there is no such lender, then 4% above the
prevailing prime rate as reported in the Wall Street Journal).

      14.   Notices.  Any notice required or permitted to be given
hereunder shall be in writing and may be delivered personally or  given by
prepaid, certified, return receipt requested, first class mail addressed:

      (a)   if to the Company, to at least two members of the Board of
Directors, c/o the Company's Secretary at the address of the Company's
principal office;

      (b)   if to Executive, at his home mailing address on file with the
Company; and

      (c)   to such other address as the party to which such notice is to
be given shall have notified (in accordance with the provisions of this
Section 14) as its substitute address for the purpose of this Agreement.

      Any notice given as aforesaid shall be deemed conclusively to have
been received on the fifth business day after such mailing.

      15.   Amendment.  It is agreed that no change or modification of this
Agreement shall be made except in a writing signed by both parties.

      16.   Severability.  In the event that any one or more of the
provisions of this Agreement shall be or become invalid, illegal, or
unenforceable in any respect, the validity, legality, and enforceability of
the remaining provisions shall not be affected thereby.

      17.   Law Governing.  The validity, interpretation, and effect of
this Agreement shall be governed by the laws of the State of New York.

      18.   Entire Agreement.  This Agreement contains the entire
understanding of the parties with respect to the employment of Executive by
the Company during the Term of Employment and with respect to
non-competition, minimum consulting, and disability and retirement benefits
(but does not affect pension and other benefit plans and arrangements in
which Executive participates).  There are no restrictions, agreements,
promises, warranties, covenants, or undertakings other than those expressly
set forth herein with respect to the Term of Employment.  As of the
Commencement Date this Agreement supersedes all prior agreements,
arrangements, and understandings between the parties, whether oral or
written, with respect to employment or consulting services of Executive on
and after the Commencement Date.

      19.   [Intentionally left blank]

      20.   Change in Control.

      (a)   A "Change in Control" of the Company shall be deemed to have
      occurred if:

                  (1)   any "person," as such term is used in Sections
            13(d) and 14(d) of the Securities Exchange Act of 1934, as
            amended (the "Exchange Act") (other than the Company or any
            corporation owned, directly or indirectly, by the shareholders
            of the Company in substantially the same proportions as their
            ownership of stock of the Company), is or becomes the
            "beneficial owner" (as defined in Rule 13d-3 under the Exchange
            Act), directly or indirectly, of securities of the Company
            representing 25% or more of the combined voting power of the
            Company's then outstanding securities;

                  (2)   there is elected 35% or more of the members of the
            Board of Directors of the Company without the approval of the
            nomination of such members by a majority of the Board serving
            prior to such election;

                  (3)   the shareholders of the Company approve a merger or
            consolidation of the Company with any other corporation, other
            than (i) a merger or consolidation which would result in the
            voting securities of the Company outstanding immediately prior
            thereto continuing to represent more than 75% of the combined
            voting power of the voting securities of the Company, or such
            surviving entity, outstanding immediately after such merger or
            consolidation; or (ii) a merger or consolidation effected to
            implement a recapitalization of the Company (or similar
            transaction) in which no "person" (as defined above) acquires
            more than 25% of the combined voting power of the Company's
            then-outstanding securities; or

                  (4)   The shareholders of the Company approve an
            agreement for the sale or disposition by the Company and all or
            substantially all of the Company's assets.

      (b)   If:
(i)   any Change in Control of the Company occurs while this Agreement is
                     effective, and

(ii)  Executive gives notice to the Company or the Company (acting upon a
                     determination of its Board of Directors) gives notice
                     to Executive, in either case to the effect that the
                     six month period called for by this subsection 20(b)
                     shall begin to run (provided that Executive shall not
                     have the right to give that notice unless Karl H.
                     Kostusiak is no longer employed as the full time
                     senior executive officer of the Company at the time or
                     he either has consented in writing to the giving of
                     that notice or has given a similar such notice for
                     himself under his applicable agreement with the
                     Company), and

(iii)  Executive's employment is terminated by Executive or by the Company
                     (other than for Executive's death or disability)
                     within six months after the date the notice provided
                     for in (ii) above is received (in Executive's case the
                     termination being effected by Executive giving notice
                     within that six month period, effective within 30 days
                     after the notice is given, that his employment is
                     terminated to the extent permitted under Section 8
                     above), regardless the reason, if any, and regardless
                     which party gave the notice provided for in (ii)
                     above,

then the Company shall, upon receipt of said notice, immediately pay,
transfer, and provide to Executive the following amounts, benefits, and
assets:

                  (1)   The Company shall pay to Executive the sum of
            Executive's full non-competition compensation and salary
            through the effective date of termination of his employment at
            the rate in effect at the time of termination or at the time
            the Change in Control occurs, whichever is higher, and an
            amount equal to the amount of any bonus which has been earned
            by him but not yet paid to him.  These two amounts shall be
            paid to Executive in a lump sum within five days following the
            effective date of termination, or in the case of a bonus which
            is not readily calculable at that time, within five days after
            the bonus can be calculated.

                  (2)   The Company shall pay to Executive an amount equal
            to three times the highest total cash compensation (including
            any base salary, non-competition compensation, bonuses, and
            consulting fees) paid Executive in any of the Company's last
            three fiscal years completed prior to such termination.  This
            amount shall be paid to Executive as provided in the last
            sentence of subsection (1) above.

                  (3)   The Company shall pay to Executive an amount equal
            to the total amounts that would be expended for the benefits to
            be provided Executive under Section 3 above on the assumption
            that Executive will continue to be compensated for
            non-competition for three years after the termination.  This
            amount shall be paid to Executive as provided in the last
            sentence of subsection (1) above either in cash or in the form
            of an annuity contract issued by an independent insurance
            company licensed to do business in New York that will provide
            payment of all such total amounts.

                  (4)   All options and other rights that Executive may
            hold to purchase or otherwise acquire Common Stock of the
            Company shall immediately become exercisable in full for the
            total number of shares that are or might become purchasable
            thereunder, in each case without further condition or
            limitation  except the giving of notice of exercise and the
            payment of the purchase price thereunder (but without amendment
            of the plan under which they were issued).  At his discretion,
            Executive may elect to surrender to the Company his rights in
            any such options and rights held by him and, upon that
            surrender, the Company shall pay him an amount in cash equal to
            the aggregate spread between the exercise prices of all those
            options and rights and the value of the Common Stock
            purchasable thereunder (or of any other security into which the
            Common Stock has been exchanged or converted) as of the date of
            the termination of employment, the value to be determined by
            the reported last sale price of the Common Stock or that other
            security (or the mean between the reported last bid and asked
            prices) on that date on NASDAQ (or, if it is not NASDAQ, on
            whatever may then be the principal exchange or quotation system
            on which the Company's Common Stock or that other security is
            traded at that time).

                  (5)   The Company shall repay any policy loans previously
            taken on the Company's  life insurance policies on Executive's
            life (provided that the directors of the Company were given
            written notice promptly after the making of any such loans
            which were made while Executive was an officer of the Company),
            and then shall transfer to Executive any and all of its right,
            title, and interest in and to all Company life insurance
            policies on Executive's life (and upon that transfer, Executive
            shall be deemed to have released the Company from any and all
            obligations it then owes to him to maintain and pay premiums on
            those policies, all other provisions of any agreements under
            which those policies were agreed to be maintained, however, to
            remain in effect).

                  (6)   In addition to the amounts specified in clauses (1)
            through (5) of this paragraph (b), the Company shall pay to
            Executive, at the same time as those amounts are paid, an
            additional amount which, after taking into account all federal,
            state, and local income and excise taxes that Executive is
            required to pay with respect to receipt of the additional
            amount under this clause (6), will render the net after-tax
            payment to Executive under this clause (6) equal to the sum of:

                        (A)   all federal, state, and local excise taxes
                  that Executive is required to pay with respect to the
                  payments made pursuant to clauses (1) through (5) above;
                  and

                        (B)   all federal, state, and local income and
                  excise taxes that Executive is required to pay with
                  respect to the payment made pursuant to this clause (6).

            The foregoing amounts of federal, state, and local income and
            excise taxes shall be determined initially by a nationally
            recognized firm of independent public accountants retained by
            Executive at his expense or, at Executive's option, by
            independent public accountants at the Company's expense, and
            such determination and the basis therefor shall be furnished in
            writing to Executive and the Company.  Payment shall be made by
            the Company in accordance with that initial determination
            regardless whether there is a dispute over the accuracy
            thereof.  If either party disputes that initial determination
            the matter shall promptly be referred to a nationally
            recognized firm of independent public accountants selected by
            the Executive (which firm shall not have been involved in the
            initial determination), and Executive and the Company shall
            promptly furnish to that firm such information as it reasonably
            requests.  The Company shall make such additional payment to
            Executive or Executive shall refund to the Company, as the case
            may be, in accordance with the latter firm's determination.
            The fees and expenses of that firm shall be borne by the
            Company.

            (c)   The Company may withhold from any payments due to
Executive under paragraph (b) such amounts as its independent public
accountants may determine are required to be withheld under applicable
federal, state, and local tax laws.

            (d)   If applicable, the provisions of this Section 20 shall
control over the provisions of Section 7.  In the event that Executive's
employment is not terminated by the Company or the Executive within the six
month period specified in Section 20(b), the provisions of Section 7 once
again shall be applicable thereafter.

            (e)  In addition, if any Change in Control of the Company
occurs while this Agreement is effective, the Company shall purchase and
fully pay for an annuity policy sufficient to pay the retirement benefits
called for by Section 9 of this Agreement and shall transfer ownership
thereof to a "rabbi" trust for the benefit of Executive (but subject to the
claims of Company creditors to the extent required under applicable tax
laws so that the transfer to the trust will not itself be an event upon
which Executive recognizes income for federal or state income tax
purposes).  In lieu of purchasing the annuity policy, the Company may
deposit cash into such a trust sufficient to provide, based on assumptions
believed reasonable in the written opinion of a nationally recognized
employee benefits organization, for assuring payment of those retirement
benefits to Executive and his spouse.

            (f)   Payment of the amounts called for by this Section 20
shall not affect the Company's obligation to pay non-competition
compensation and benefits under Section 3 above or retirement benefits
under Section 9 and, if elected by Executive, Section 10 above.

      21.   Successors and Assigns.  This Agreement shall inure to the
benefit of and be binding upon the heirs, legatees, administrators,
successors, and assigns of the respective parties.

      IN WITNESS WHEREOF, Executive for himself, and the undersigned
director of the Company, acting on behalf of the Company by authority of
its Board of Directors, have executed this Agreement as of the day and year
first above written.

                                          /s/ David B. Lederer
                                          David B. Lederer, Executive


                                          DETECTION SYSTEMS, INC.

                                          By: /s/ Donald R. Adair
                                          Donald R. Adair, Chairman of the
                                          Compensation Committee of the
                                          Board of Directors