EXHIBIT 3b
                               
                               
                               
                            BY-LAWS
                               
                               
                              OF
                               
                               
                    DETECTION SYSTEMS, INC.
                               
                               
                         [as amended]
                               
                               
                               
                               
                           ARTICLE I
                               
                         SHAREHOLDERS


          Section 1.     Annual Meetings.   The annual meeting
of the shareholders for the election of directors and the
transaction of other business shall be held each year on such
day and at such hour in July, or on such other date, as shall
be fixed by the Board of Directors. Annual meetings of
shareholders shall be held at the principal office of the
Corporation or at such other place, within or without the State
of New York, as may be fixed by the Board of Directors.

          Section 2.     Special Meetings.   A special meeting
of the shareholders may be called at any time by the holders of
a majority of the outstanding shares, by the President, by the
Secretary or by the Board of Directors and shall be held at
such place, within or without the State of New York, on such
day and at such hour as is fixed in the call of the meeting.

          Section 3.     Record Date for Meetings and Other
Purposes.  For the purpose of determining the shareholders
entitled to notice of or to vote at any meeting of shareholders
or any adjournment thereof, or to express consent to or dissent
from any proposal without a meeting, or for the purpose of
determining shareholders entitled to receive payment of any
dividend or entitled to notice of or to vote at any meeting of
shareholders or any adjournment thereof, or to express consent
to or dissent from any proposal without a meeting, or for the
purpose of determining shareholders entitled to receive payment
of any dividend or the allotment of any rights, or for the
purpose of any other action, the Board of Directors may fix, in
advance, a date as the record date for any such determination
of shareholders. Such date shall not be more than fifty nor
less than ten days before the date of such meeting, nor more
than fifty days prior to any other action.

          If no record date is so fixed by the Board of
Directors, (a) the record date for the determination of
shareholders entitled to notice of or to vote at a meeting of
shareholders shall be at the close of business on the day next
preceding the day on which notice is given, or if notice is not
given by reason of due waiver thereof, the day on which the
meeting is held, and (b) the record date for determining
shareholders for any other purpose shall be at the close of
business on the day on which the resolution of the Board of
Directors relating thereto is adopted.
          A determination of shareholders of record entitled to
notice of or to vote at any meeting of shareholders, made in
accordance with this Section, shall apply to any adjournment
thereof, unless the Board of Directors fixes a new record date
under this Section for the adjourned meeting.

          Section 4.     Notice of Meetings.   Notice of each
meeting of shareholders shall be in writing and shall state the
place, date, and hour of the meeting. Notice of a special
meeting also shall state the purpose or purposes for which the
meeting is called and shall indicate who called the meeting. A
copy of the notice of any meeting shall be given, personally or
by mail, not less than ten (10) nor more than fifty (50) days
before the date of the meeting, to each shareholder entitled to
vote at the meeting. If mailed, such notice is given when
deposited in the United States mail, with postage thereon
prepaid, directed to the shareholder at such address as appears
on the record of shareholders, or, if the shareholder shall
have filed with the Secretary a written request that notices be
mailed to some other address, then directed to the shareholder
at such other address.

          Section 5.     Organization.  At each meeting of
shareholders, the President, or in the President's absence, a
Vice President, shall preside and the Secretary, or in the
Secretary's absence an Assistant Secretary, shall act as
secretary of the meeting. If none of those designated to
preside or to act as secretary of the meeting shall be present,
the shareholders present in person or by proxy and entitled to
vote at the meeting shall select someone to preside or to act
as secretary, as may be needed.

          Section 6.     Quorum.   At each meeting of
shareholders, the holders of a majority of the shares entitled
to vote thereat, present in person or by proxy, shall
constitute a quorum for the transaction of business.

          Section 7.     Voting.   At each meeting of
shareholders, every shareholder of record shall be entitled to
cast one vote for every share of stock standing in his or her
name on the record of shareholders.  All matters shall be
determined by a majority of the votes cast, except that
directors shall be elected by a plurality of the votes cast.

          Section 8.     Proxies.   Every shareholder entitled
to vote at a meeting of shareholder or to express consent or
dissent without a meeting may authorize another person or
persons to act for her or him by proxy. Every proxy must by
signed by the shareholder or the shareholder's attorney-in-
fact. No proxy shall be valid after the expiration of eleven
months from the date thereof unless otherwise provided in the
proxy. Every proxy shall be revocable at the pleasure of the
shareholder executing it, except as otherwise provided by law.

          Section 9.     List of Shareholders at Meetings. A
list of shareholders as of the record date, certified by the
corporate officer responsible for its preparation or by a
transfer agent, shall be produced at any meeting of
shareholders upon the request thereat or prior thereto of any
shareholder.

                          ARTICLE II
                      BOARD OF DIRECTORS
                               
          Section 1.     General Power.   Except as otherwise
provided in the Certificate of Incorporation of the
Corporation, the business, property, and affairs of the
Corporation shall be managed under the direction of its Board
of Directors.

          Section 2.     Number.   The number of directors
constituting the entire Board of Directors shall be such
number, not less than three, as shall be fixed from time to
time by the Board of Directors, provided that no decrease in
the number of directors shall shorten the term of any incumbent
director.

          Section 3.     Election and Term of Directors.
Directors shall be elected at the annual meeting of
shareholders. Each director shall hold office until the next
annual meeting and until the director's successor has been
elected and qualified.

          Section 4.     Meetings of the Board.  An annual
meeting of the Board of Directors shall be held in each year
directly after adjournment of the annual meeting of
shareholders. Other regular meetings of the Board shall be held
at such times as may from time to time be fixed by resolution
of the Board. Special meetings of the Board may be held at any
time upon the call of the President or any two directors.
Meetings of the Board of Directors shall be held at such place,
within or without the State of New York, as from time to time
may be fixed by resolution of the Board or by order of the
President. If no place is so fixed, meetings of the Board shall
be held at the principal office of the Corporation.

          Section 5.     Notice of Meetings.  Notice of regular
meetings of the Board of Directors need not be given. Notice of
each special meeting shall be mailed to each director,
addressed to the address last given by each director to the
Secretary or, if none has been given, at the director's
residence or usual place of business, at least three (3) days
before the day on which the meeting is to be held, or shall be
sent to the director by telegraph, cable, wireless, or similar
means so addressed or shall be delivered personally or by
telephone, at least twenty-four (24) hours before the time the
meeting is to be held. Each notice shall state the time and
place of the meeting but need not state the purposes thereof
except as otherwise expressly provided. Notices of any such
meeting need not be given to any director who submits a signed
waiver of notice whether before or after the meeting or who
attends the meeting without protesting, prior thereto or at its
commencement, the lack of notice.

          Section 6.     Quorum and Manner of Acting.   At each
meeting of the Board of Directors the presence of a majority of
the entire Board shall constitute a quorum for the transaction
of business, and the vote of a majority of the directors
present at the time of the vote, if a quorum is present at that
time, shall be the act of the Board.

          Section 7.     Action Without a Meeting.   Any action
required or permitted to be taken by the Board or any committee
thereof may be taken without a meeting if all members of the
Board or the committee consent in writing to the adoption of a
resolution authorizing the action. The resolution and the
written consents thereto by the members of the Board or
committee shall be filed with the minutes of the proceedings of
the Board or committee.

          Section 8.     Participation in Board Meetings by
Conference Telephone.   Any one or more members of the Board of
Directors or any committee thereof may participate in a meeting
of such Board or committee by means of a conference telephone
or similar communications equipment allowing all persons
participating in the meeting to hear each other at the same
time. Participation by such means shall constitute presence in
person at a meeting.

          Section 9.     Executive and Other Committees of
Directors.   The Board of Directors, by resolution adopted by a
majority of the entire Board, may designate from among its
members an executive committee and other committees, each
consisting of three or more directors, and each of which, to
the extent provided in the resolution, shall have all the
authority of the Board, except that no such committee shall
have authority as to the following matters:

          (1)  The submission to shareholders of any action that needs
            shareholders' approval under the New York Business Corporation
            Law;
          
          (2)  The filling of vacancies in the Board of Directors or in
            any committee;
          
          (3)  The fixing of compensation of the directors for serving on
            the Board or on any committee;
          
          (4)  The amendment or repeal of the By-laws, or the adoption of
            new By-laws; and
          
          (5)  The amendment or repeal of any resolution of the Board
            which by its terms shall not be so amendable or repealable.
          
Unless a greater proportion is required by the resolution
designating a committee of the Board of Directors, a majority
of the entire authorized number of members of such committee
shall constitute a quorum for the transaction of business or of
any specified item of business, and the vote of a majority of
the members present at the time of such vote, if a quorum is
present at such time, shall be the act of the committee. The
Board may designate one or more directors as alternate members
of any such committee, who may replace any absent member or
members at any meeting of such committee.

          Section 10.    Resignation and Removal.   Any
director may resign at any time by giving written notice to the
President or to the Secretary. Such resignation shall take
effect at the time specified therein or, if no time be
specified then on delivery and unless otherwise specified
therein, the acceptance of such resignation by the Board of
Directors shall not be needed to make it effective. Any or all
of the directors may be removed, at any time, with or without
cause, by vote of the shareholders at a special meeting of
shareholders, and any vacancy thereby created may be filled at
said meeting by vote of the shareholders and, if not so filled,
then by the directors as provided in Section 11 of this
Article.

          Section 11.    Vacancies.   Newly created
directorships resulting from an increase in the number of
directors and vacancies occurring in the Board of Directors for
any reason may be filled by vote of a majority of the directors
then in office, even if less than a quorum exists. A director
elected to fill a newly created directorship or a vacancy shall
hold office until the next annual meeting of shareholders and
until such director's successor has been elected and qualified.


                          ARTICLE III
                           OFFICERS
                               
          Section 1.     Officers Enumerated.   The officers of
the Corporation shall be a President, one or more Vice
Presidents, a Secretary, and a Treasurer, and such other
officers as the Board of Directors may in its discretion elect.
Any two or more offices may be held by the same person, except
that the offices of President and Secretary may not be held by
the same person unless all of the issued and outstanding stock
of the Corporation is owned by that person.

          Section 2.      Election and Term of Office.   All
officers shall be elected by the Board of Directors at its
first meeting held after the annual election of directors. The
officers need not be directors. Unless elected for a lesser
term, and subject always to the right of the Board of Directors
to remove an officer with or without cause, each officer shall
hold office for one year and until such officer's successor has
been elected and qualified.

          Section 3.     The President.   The President shall
be the chief executive officer of the Corporation and, subject
to the determinations of the Board of Directors, shall have
general control and management of the business, property, and
affairs of the Corporation. The President shall preside at all
meetings of shareholders and of the Board. In the absence or
incapacity of any other officer of the Corporation, the
President shall have the authority and may perform the duties
of that officer.

          Section 4.     The Vice Presidents.   Each Vice
President, if any, shall, in the absence or incapacity of the
President and in order of seniority as fixed by the Board, have
the authority and perform the duties of the President, and each
shall have such other authority and perform such other duties
as the Board of Directors may prescribe.

          Section 5.     The Secretary.   The Secretary (a)
shall attend all meetings of the Board of Directors and all
meetings of the shareholders and record all votes and the
minutes of all proceedings in a book to be kept for that
purpose, (b) shall perform like duties for committees of the
Board when required, (c)  shall give, or cause to be given,
notice of all meetings of the shareholders and special meetings
of the Board of Directors, and (d) shall have such other
authority and perform such other duties as usually pertain to
the office or as may be prescribed by the Board of Directors.
The Secretary shall keep in safe custody the seal of the
Corporation and, when authorized by the Board of Directors or
the President, affix the same to any instrument requiring it,
and when so affixed, it shall be attested by the signature of
the Secretary or Treasurer.

          Section 6.     The Treasurer.   The Treasurer (a)
shall have the care and custody of all the moneys and
securities of the Corporation, (b) shall keep or cause to be
kept complete and accurate books of account of all moneys
received and paid on account of the Corporation, (c) shall sign
such instruments as require the Treasurer's signature, and (d)
shall have such other authority and perform such other duties
as usually pertain to the office or as the Board of Directors
may prescribe.

          Section 7.     Assistant Officers.   Any Assistant
Vice President, Assistant Secretary, or Assistant Treasurer
elected by the Board of Directors, (a) shall assist the Vice
President, Secretary, or Treasurer, respectively, as the case
may be, (b) shall possess that officer's authority and perform
that officer's duties in that officer's absence or incapacity,
and, (c) shall have such other authority and perform such other
duties as the Board of Directors may prescribe.

          Section 8.     Appointed Officers.   The Board of
Directors may delegate to any officer or committee the power to
appoint and to remove any subordinate officer, agent, or
employee.

          Section 9.     Securities of Other Corporations.
The President or the Treasurer may, with respect to any shares
of stock or other securities issued by any other corporation or
other business organization and held by the Corporation,
exercise voting and similar rights on behalf of the Corporation
and execute proxies for that purpose. In addition, any such
officer may endorse for sale or transfer and may sell or
transfer for and on behalf of the Corporation any such stock or
other securities and may appoint proxies or attorneys for that
purpose.


                          ARTICLE IV
                   SHARES AND THEIR TRANSFER
                               
          Section 1.     Certificates of Stock.   Every
shareholder shall be entitled to have one or more certificates,
in such form as the Board of Directors may from time to time
prescribe, representing in the aggregate the number of shares
of stock of the Corporation owned by said shareholder, which
certificates shall be signed by or in the name of the
Corporation by the president or a Vice President and by the
Treasurer or an Assistant Treasurer or the Secretary or an
Assistant Secretary.

          Section 2.     Transfers.   Shares of stock of the
Corporation shall be transferable on the books of the
Corporation by the registered holder thereof in person or by
such holder's duly authorized attorney, but, except as
hereinafter provided in the case of loss, destruction, or
mutilation of certificates, no transfer of shares shall be
entered until the previously issued certificate representing
those shares shall have been surrendered and canceled. Except
as otherwise required by law, the Corporation shall be entitled
to treat the person registered as the holder of shares on its
books as the owner thereof for all purposes regardless of any
notice or knowledge to the contrary.

          Section 3.     Stock Transfer Books.   In the event
of declaration of a dividend the stock transfer books of the
Company shall not be closed but a record date will be fixed
upon which the Company's transfer agent shall take a record of
all shareholders entitled to the dividend without actually
closing said stock transfer books.

          Section 4.     Lost, Destroyed or Mutilated
Certificates.   The Corporation may issue a new certificate
representing shares of stock of the same tenor and the same
number of shares in place of a certificate theretofore issued
by it that is alleged to have been lost, stolen, or destroyed;
provided, however, that the Board of Directors may require the
owner of the lost, stolen, or destroyed certificate, or such
owner's legal representative, to give the Corporation a bond of
indemnity, in form and with one or more sureties satisfactory
to the Board, sufficient to indemnify the Corporation against
any claim that may be made against it on account of the alleged
loss, theft, or destruction of any such certificate or the
issuance of such new certificate.


                           ARTICLE V
                            GENERAL
                               
          Section 1.     Seal.   The seal of the Corporation
shall be in the form of a circle and shall bear matters deemed
appropriate by the Board of Directors.

          Section 2.     Indemnification of Directors and
Officers.
(a)  Right to Indemnification.  Except as prohibited by law or
  as provided in Paragraph (b) below, the Corporation shall
  indemnify each person against all reasonable expenses and any
  other liability paid or incurred by such person in connection
  with any actual or threatened claim, action, suit or
  proceeding, whether civil, criminal, administrative,
  investigative, or other, or whether brought by or in the right
  of the Corporation or otherwise, in which such person may be
  involved as a party or otherwise, by reason of the fact that
  such person or such person's testator or intestate is or was a
  director or officer of the Corporation, or serves or served in
  any capacity at the request of the Corporation any other
  corporation, partnership, joint venture, trust, employee
  benefit plan or other enterprise (any such actual or threatened
  claim, action, suit or proceeding hereinafter being referred to
  as an "action"). To the maximum extent permitted by law, the
  Corporation shall make advances of expenses incurred by such
  person in connection with an action prior to final disposition
  of such action, subject to receipt by the Corporation of an
  undertaking by or on behalf of such person to repay such
  advances to the extent such person is ultimately found not to
  be entitled to indemnification. As used herein, "expenses"
  shall include, without limitation, costs of investigation,
  including experts, the costs of defense of actions and appeals
  therefrom and fees and expenses of counsel selected by such
  person. As used herein, "liability" shall include amounts of
  judgments, excise taxes, fines and penalties, amounts paid in
  settlement and any other amounts which the person may be
  obligated to pay as a result of any action.

(b)  Exclusions.   No such indemnification shall be made to or
  on behalf of any person if a judgment or other final
  adjudication adverse to such person establishes that either (i)
  such person's acts were committed in bad faith, or were the
  result of active and deliberate dishonesty, and were material
  to the action, or (ii) that such person gained in fact a
  financial profit or other economic advantage to which such
  person was not legally entitled.

(c)  Indemnification Not Exclusive.  The right of
  indemnification provided for herein shall not be deemed
  exclusive of any other rights to which persons seeking
  indemnification hereunder may be entitled under applicable law,
  by agreement or otherwise, and the provisions hereof shall
  inure to the benefit of the heirs, beneficiaries and legal
  representative of persons entitled to indemnification hereunder
  and shall be applicable to actions arising from acts or
  omissions occurring before or after the adoption hereof. The
  Corporation is authorized to enter into agreements with any of
  its directors or officers extending rights to indemnification
  and advancement of expenses to such person to the fullest
  extent permitted by applicable law, but the failure to enter
  into any such agreement shall not affect or limit the rights of
  such person pursuant to this By-law, it being expressly
  recognized hereby that all directors or officers of the
  Corporate, by serving as such after the adoption hereof, are
  acting in reliance on this Section 2 and that the Corporation
  is estopped to contend otherwise.

(d)  Contract Rights.   The right of indemnification under this
  Section 2 shall be deemed to constitute a contract between the
  Corporation and the persons entitled to indemnification and may
  not, without the consent of such person, be amended or repealed
  with respect to any event, act or omission occurring or
  allegedly occurring prior to the end of the term of office such
  person is serving when such amendment or repeal is adopted.

(e)  Miscellaneous.  Persons who are not directors or officers
  of the Corporation shall be similarly indemnified and entitled
  to advancement or reimbursement of expenses to the extent
  authorized at any time by the Board of Directors. The
  Corporation shall be deemed to have requested a person to serve
  an employee benefit plan where the performance of such person's
  duties also involves duties or services to the plan or its
  participants or beneficiaries.

          Section 3.     Fiscal Year.   The fiscal year of the
Corporation shall end at the close of business on March 31 of
each calendar year.


                          ARTICLE VI
                          AMENDMENTS
                               
          Section 1.     Power to Amend.   Both the
shareholders and the Board of Directors shall have the power to
adopt, amend, or repeal By-laws. Any By-law adopted by the
Board may be amended or repealed by the shareholders at any
annual or special meeting of the shareholders.

          Section 2.     Amendment Affecting Election of
Directors.   If any By-law regulating an impending election of
directors is adopted, amended, or repealed by the Board, there
shall be set forth in the notice of  the next meeting of
shareholders for the election of directors the By-law so
adopted, amended or repealed, together with a concise statement
of the changes made.