EXHIBIT 3a
                               
                               
                               
                 CERTIFICATE OF INCORPORATION
                               
                              OF
                               
                    DETECTION SYSTEMS, INC.
                               
                         [as amended]
                               
               Under Section 402 of the Business
                    Corporation Law of the
                       State of New York
                               
                               
          First:  The name of the corporation is:
                               
                    DETECTION SYSTEMS, INC.
                               
          Second:  The purposes for which it is formed are as
          follows:
                               
               To design, develop, manufacture, assemble,
               fabricate, import, lease, market, purchase
               or otherwise acquire and generally to trade
               and deal in and with, as principal or
               agent, at wholesale, retail, on commission
               or otherwise, materials, components and
               devices of a mechanical, electrical,
               optical or chemical nature for use in
               detection systems, signal systems and other
               systems.
               
               To acquire by purchase, assignment, grant,
               license or otherwise, to apply for, secure,
               lease or in any manner obtain, to develop,
               hold, own, use, exploit, operate, enjoy and
               introduce, to sell, assign, lease,
               mortgage, pledge, grant licenses and rights
               of all kinds in respect of, or otherwise
               dispose of, and generally to deal in and
               with and turn to account for any or all
               purposes, either for itself or as nominee
               or agent for others:
               
                 (1)    Any and all inventions, devices, processes, discoveries
                 and formulae, and improvements and modifications thereof and
                 rights and interests therein;
                 
                 (2)    Any and all letters patent or applications for letters
                 patent of the United States of America or of any other country,
                 state, locality or authority, and any and all rights, interests
                 and privileges connected therewith or incidental or
                 appertaining thereto;
                 
                 (3)    Any and all copyrights granted by the United States of
                 America or any other country, state, locality or authority, and
                 any and all rights, interests and privileges connected
                 therewith or incidental or appertaining thereto.

               To purchase or otherwise acquire,
               hold, own, sell, lease or otherwise
               dispose of real property, improved or
               unimproved, and personal property,
               tangible or intangible, including,
               without limitation, goods, wares and
               merchandise of every description and
               the securities and obligations of any
               issuer, whether or not incorporated.
               
          To do all and everything necessary, suitable, or
proper for the accomplishment of any of the purposes, the
attainment of any of the objects or the furtherance of any
of the powers hereinbefore set forth, either alone or
connection with other corporations, firms or individuals
and either as principals, or agents and to do every other
act or acts, thing or things incidental or appurtenant to
or growing out of or connection with the aforesaid
objects, purposes or powers or any of them.
          The foregoing enumeration of specific powers
shall not be deemed to limit or restrict in any manner the
general powers of the corporation, and the enjoyment and
exercise thereof, as conferred by the laws of the State of
New York upon corporations organized under the provisions
of the Business Corporation Law.
          Third:  The office of the corporation within the
State of New York is to be located in the City of
Rochester, County of Monroe.
          Fourth: The aggregate number of shares which the
Corporation shall have authority to issue is Twelve
Million (12,000,000) common shares, with par value of Five
Cents ($.05) per share.
          Fifth: No holder of shares of the Corporation of
any class now or hereafter authorized, shall have any
preferential or preemptive right to subscribe for,
purchase or receive any shares of the corporation of any
class, now or hereafter authorized, or any options or
warrants for such shares, or any rights to subscribe to or
purchase such shares, or any securities convertible into
or exchangeable for such shares, which may at any time be
issued, sold or offered for sale by the Corporation.
          Sixth:  The Secretary of State is designated the
agent of the Corporation upon whom process against the
Corporation may be served.  The post office address to
which the Secretary of State shall mail a copy of any
process against the Corporation so served upon him is 130
Perinton Parkway, Fairport, New York  14450.