SECURITIES AND EXCHANGE COMMISSION
                                WASHINGTON, D.C.  20549


                                     FORM 8-K

                                  CURRENT REPORT


                        Pursuant to Section 13 or 15(d) of
                        the Securities Exchange Act of 1934


                        Date of Report:   November 8, 1994
                         (Date of earliest event reported)

                           INSTRUMENT SYSTEMS CORPORATION
               (Exact name of registrant as specified in its charter)



      Delaware                   1-6620                11-1893410
   (State or other           (Commission             (IRS Employer
    jurisdiction of          File Number)            Identification
    incorporation)                                      Number)



    100 Jericho Quadrangle, Jericho, New York             11753
    (Address of principal executive offices)            (Zip Code)




Registrant's telephone number including area code    (516)  938-5544





(Former name of former address, if changed since last report.)

ITEM 5.   OTHER EVENTS

     (a)  On April 2, 1986, the Board of Directors of Instrument Systems
Corporation (the "Company") declared a dividend distribution of one common stock
purchase right (the "Rights") for each outstanding share of Common Stock, $.25
par value (the "Common Stock") of the Company.  The distribution was payable on
May 2, 1986 to the shareholders of record on May 2, 1986.  Once exercisable,
each Right entitles the registered holder thereof to purchase from the Company
one-half (1/2) share of the Common Stock at an exercise price of $6.00 per
one-half of a share (the "Purchase Price"), subject to adjustment.  The
description and terms of the Rights are set forth in a Rights Agreement, as
amended (the "Rights Agreement") between the Company and American Stock Transfer
Company, as Rights Agent (the "Rights Agent").  On November 8, 1994, the Company
and the Rights Agent entered into an Amendment, dated as of November 8, 1994, to
the Rights Agreement (the "Amendment"), a copy of which is filed as Exhibit 4
hereto and is hereby incorporated herein by reference.

     Until the earlier  to occur of (i) ten days following a public announcement
that a person or group of affiliated or associated persons (an "Acquiring
Person") acquired, or obtained the right to acquire, beneficial ownership of 15%
or more of the outstanding shares of the Common Stock or (ii) ten business days
(or such later date as may be determined by action of the Board of Directors
prior to such time as any person becomes an Acquiring Person) following the
commencement, or announcement of an intention to make, a tender offer or
exchange offer by a person (other than the Company, any wholly-owned subsidiary
of the Company or certain employee benefit plans) which, if consummated, would
result in such person becoming an Acquiring Person (the earlier of the dates
being called the "Distribution Date"), the Rights will be evidenced by the
Common Stock certificate with a copy of a Summary of Rights attached hereto.
The Rights Agreement provides that, until the Distribution Date, the Rights will
be transferred with and only with the Common Stock.  Until the Distribution Date
(or earlier redemption or expiration of the Rights), new Common Stock
certificates issued after May 2, 1986 upon transfer or new issuance of the
Common Stock will contain a notation incorporating the Rights Agreement by
reference.  In certain circumstances, shares of Common Stock issued after the
Distribution Date will be accompanied by Rights.  Until the Distribution Date
(or earlier redemption or expiration of the Rights), the surrender for transfer
of any of the Common Stock certificates outstanding, even without a copy of the
Summary of Rights attached thereto, will also constitute the transfer of the
Rights associated with the Common Stock represented by such certificate. As soon
as practicable following the Distribution Date, separate certificates evidencing
the Rights  ("Right Certificates") will be mailed to holders of record of the
Common Stock as of the close of business on the Distribution Date and such
separate Right Certificates alone will evidence the Rights.  No less than two
Rights, and only integral multiples of two Rights, may be exercised at any one
time by any holder of Rights.

     The Rights are not exercisable until the Distribution Date.  The Rights
will expire on May 2, 1996, unless earlier redeemed by the Company as described
below.

     The Purchase Price payable, and the number of halves of shares of the
Common Stock or other securities or property issuable, upon exercise of the
Rights are subject to adjustment from time to time to prevent dilution (i) in
the event of a stock dividend on, or a subdivision, combination or
reclassification of, the Common Stock, (ii) upon the grant holders of the Common
Stock of certain rights or warrants to subscribe for shares of the Common Stock
or convertible securities at less than the current market price of the Common
Stock or (iii) upon the distribution to holders of the Common Stock of evidences
of indebtedness or assets (excluding regular periodic cash dividends out of
earnings or retained earnings at a rate not in excess of 125% of the rate of the
last cash dividend theretofore paid or dividends payable in the Common Stock) or
of subscription rights or warrants (other than those referred to above).

     In the event that after the Distribution Date the Company were acquired in
a merger or other business combination transaction or that 50% or more of its
assets or earning power  were sold, proper provision is to be made so that each
holder of a Right, other than Rights that were or are beneficially owned by  the
Acquiring Person (which will thereafter be void), shall thereafter have the
right to receive, upon the exercise thereof at the then current Purchase Price
of the Right, that number of shares of common stock of the acquiring company
which at the time of such transaction would have a market value of two times the
Purchase Price of the Right.  In the event that at any time any person shall
become an Acquiring Person, proper provision shall  be made so that each holder
of a Right, other than Rights that were or are beneficially owned by the
Acquiring Person (which will thereafter be void), shall thereafter have the
right to receive, upon the exercise thereof at the then current Purchase Price,
that number of shares of the Common Stock which at the time of such transaction
would have a market value of two times the exercise price of the Right.

     With certain exceptions, no adjustment in the Purchase Price will be
required until cumulative adjustments require an adjustment of at least 1% in
such Purchase Price.  No fractional shares will be issued and, in lieu thereof,
an adjustment in cash will be made based on the market price of the Common Stock
on the last trading date prior to the date of exercise.  No less than two
Rights, and only integral multiples of two Rights, may be exercised at any time
and no Rights may be exercised that would entitle the holder thereof to any
fractional share greater than one-half of a share unless concurrently therewith
such holder purchases an additional fraction of a share which, when added to the
number of shares to be received upon such exercise, equals an integral number of
shares.

     At any time prior to the time at which a person or group or affiliated or
associated persons has acquired beneficial ownership of 15% or more of the
outstanding shares of the Common Stock of the Company (the "Shares Acquisition
Date"), the Board of Directors of the Company may redeem the Rights in whole,
but not in part, at a price of $.01 per Right (the "Redemption Price").
Immediately upon the action of the Board of Directors of the Company electing to
redeem the Rights, the Company shall make announcement thereof, and upon such
election, the right to exercise the Rights will terminate and the only right of
the holders of Rights will be to receive the Redemption Price.  In addition, the
Rights Agreement permits the Board of Directors, following the acquisition by a
person or group of beneficial ownership of 15% or more of the Common Stock (but
before an acquisition of 50% or more of the Common Stock), to exchange the
Rights (other than Rights owned by such 15% person or group), in whole or in
part, for Common Stock, at an exchange ratio of one share of Common Stock per
Right.

     Until a Right is exercised, the holder thereof, as such, will have no
rights as a shareholder of the Company, including, without limitation, the
right to vote or to receive dividends.

     The provisions of the Rights Agreement may be amended by the Board of
Directors in order to cure any ambiguity or correct any defect or inconsistency
and by the Continuing Directors (as defined in the Rights Agreement), prior to
the Distribution Date, to make changes deemed to be in the best interests of the
holders of the Rights or, after the Distribution Date, to make such other
changes which do not adversely affect the interests of the holders of the Rights
(excluding the interests of any Acquiring Person and its Affiliates and
Associates).

     The Rights have certain anti-takeover effects.  The Rights will cause
substantial dilution to a person who attempts to acquire the Company without the
consent of the Board of Directors.  The Rights will not affect a transaction
approved by the Company prior to the existence of an Acquiring Person, because
the Rights can be redeemed before the consummation of such transaction.

     The Rights Agreement and the Amendment are attached hereto as exhibits and
are incorporated herein by reference.  The foregoing description of the Rights
is qualified by reference to such exhibits.

     (b)  The Company also amended its By-Laws to require stockholders, among
other things, to give advance notice prior to proposing any business to be acted
upon at a meeting of shareholders or prior to nominating persons for election as
directors.  A copy of the Company's By-Laws as amended through November 8, 1994
is attached as Exhibit 3 and incorporated herein by reference.

ITEM 7.   FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND EXHIBITS

     (c)  Exhibits

          3    By-Laws of Instrument Systems Corporation, as amended, through
               November  8, 1994.

          4    Form of Rights Agreement dated as of April 2, 1986 between
               Instrument Systems Corporation and American Stock Transfer &
               Trust  Company, as Rights Agent (previously filed as an
               exhibit to the Registration Statement on Form 8-A, dated
               January 19, 1993, with respect to the Rights).

          4.1  Form of Amendment to the Rights Agreement dated as of
               November 8, 1994, between Instrument Systems Corporation and
               American Stock Transfer & Trust Company, as Rights Agent.



                                   SIGNATURE

     Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf of the
undersigned thereunto duly authorized.


Dated:    November  21, 1994


                          INSTRUMENT SYSTEMS CORPORATION

                          By:  Patrick Alesia
                               ----------------------------
                               Patrick Alesia
                               Vice President and Treasurer

                                  EXHIBIT INDEX


EXHIBIT NO.          DESCRIPTION




     3    By-Laws of Instrument Systems Corporation, as amended,
          through November  8, 1994.

     4    Rights Agreement dated as of April 2, 1986 between Instrument Systems
          Corporation and American Stock Transfer & Trust  Company, as Rights
          Agent (previously filed as an exhibit to the Registration Statement
          on Form 8-A, dated January 19, 1993, with respect to the Rights).

     4.1  Form of Amendment to the Rights Agreement dated as of November 8, 
          1994, between Instrument Systems Corporation and American Stock 
          Transfer & Trust Company, as Rights Agent.

NOVEMBER 8, 1994                              Exhibit 3


                      INSTRUMENT SYSTEMS CORPORATION

                               * * * * * *

                             AMENDED BY-LAWS

                               * * * * * *


                                ARTICLE I

                                 OFFICES

     Section 1.  The registered office shall be in the City of Wilmington,
County of New Castle, State of Delaware.

     Section 2.  The corporation may also have offices at such other places both
within and without the State of Delaware as the board of directors may from time
to time determine or the business of the corporation may require.

                               ARTICLE II

                         MEETING OF STOCKHOLDERS

     Section 1.  All meetings of the stockholders for the election of directors
shall be held in the City of Wilmington, State of Delaware, at such place as may
be fixed from time to time by the board of directors, or at such other place
either within or without the State of Delaware as shall be designated from time
to time by the board of directors and stated in the notice of the meeting.
Meetings of stockholders for any other purpose may be held at such time and
place, within or without the State of Delaware, as shall be stated in the notice
of the meeting or in a duly executed waiver of notice thereof.

     Section 2.  Annual meetings of stockholders shall be held on the third
Thursday of March if not a legal holiday, and if a legal holiday, then on the
next secular day following, at 11:00 a.m., or at such other date and time as
shall be designated from time to time by the board of directors and stated in
the notice of the meeting, at which they shall elect by a plurality vote those
directors whose terms have expired pursuant to the provisions of the certificate
of incorporation, and transact such other business as may properly be brought
before the meeting.

     Section 3.  Written notice of the annual meeting stating the place, date
and hour of the meeting shall be given to each stockholder entitled to vote at
such meeting not less than ten nor more than fifty days before the date of the
meeting.

     Section 4.  The officer who has charge of the stock ledger of the
corporation shall prepare and make, at least ten days before every meeting of
stockholders, a complete list of the stockholders entitled to vote at the
meeting, arranged in alphabetical order, and showing the address of each
stockholder and the number of shares registered in the name of each stockholder.
Such list shall be open to the examination of any stockholder, for any purpose
germane to the meeting, during ordinary business hours for a period of at least
ten days prior to the meeting, either at a place within the city where the
meeting is to be held, which place shall be specified in the notice of the

meeting, or, if not specified, at the place where the meeting is to be held.
The list shall also be produced and kept at the time and place of the meeting
during the whole time thereof, and may be inspected by any stockholder who is
present.

     Section 5.  Special meetings of the stockholders, for any purpose or
purposes, may be called only at the written request of stockholders owning at
least sixty-six and two-thirds (66-2/3%) percent of the entire voting power of
the corporation's capital stock.  Such request shall state the purpose or
purposes of the proposed meeting.

     Section 6.  Written notice of a special meeting stating the place, date and
hour of the meeting and the purpose for which the meeting is called, shall be
given not less than ten nor more than fifty days before the date of the meeting,
to each stockholder entitled to vote at such meeting.

     Section 7.  (A)   (1)  Nominations of persons for election to the board of
directors of the corporation and the proposal of business to be considered by
the stockholders may be made at an annual meeting of stockholders (a) pursuant
to the Corporation's notice of meeting, (b) by or at the direction of the board
of directors or (c) by any stockholder of the corporation who was a stockholder
of record at the time of giving of notice provided for in this By-law, who is
entitled to vote at the meeting and who complies with the notice procedures set
forth in this By-law.

                     (2)  For nominations or other business to be properly
brought before an annual meeting by a stockholder pursuant to clause (c) of
paragraph (A) (1) of this by-law the stockholder must have given timely notice
thereof in writing to the Secretary of the corporation and such other business
must otherwise be a proper matter for stockholder action.  To be timely, a
stockholder's notice shall be delivered to the Secretary at the principal
executive offices of the corporation not later than the close of business on the
60th day nor earlier than the close of business on the 90th day prior to the
first anniversary of the preceding year's annual meeting; provided, however,
that in the event that the date of the annual meeting is more than 30 days
before or more than 60 days after such anniversary date, notice by the
stockholder to be timely must be so delivered not earlier than the close of
business on the 90th day prior to such annual meeting and not later than the
close of business on the later of the 60th day prior to such annual meeting or
the 10th day following the day on which public announcement of the date of such
meeting is first made by the Corporation.  In no event shall the public
announcement of an adjournment of an annual meeting commence a new time period
for the giving of a stockholder's notice as described above.  Such stockholder's
notice shall set forth (a) as to each person whom the stockholder proposes to
nominate for election or reelection as a director all information relating to
such person that is required to be disclosed in solicitations of proxies for
election of directors in an election contest, or is otherwise required, in each
case pursuant to Regulation 14A under the Securities Exchange Act of 1934, as
amended (the "Exchange Act") and Rule 14a-11 thereunder (including such person's
written consent to being named in the proxy statement as a nominee and to
serving as a director if elected); (b) as to any other business that the
stockholder proposes to bring before the meeting, a brief description of the
business desired to be brought before the meeting, the reasons for conducting
such business at the meeting and any material interest in such business of such
stockholder and the beneficial owner, if any, on whose behalf the proposal is
made; and (c) as to the stockholder giving the notice and the beneficial owner,
if any, on whose behalf the nomination or proposal is made (i) the name and
address of such stockholder, as they appear on the Corporation's books, and of

such beneficial owner and (ii) the class and number of shares of the corporation
which are owned beneficially and of record by such stockholder and such
beneficial owner.

                     (3)  Notwithstanding anything in the second sentence of
paragraph (A) (2) of this by-law to the contrary, in the event that the number
of directors to be elected to the board of directors of the corporation is
increased and there is no public announcement by the corporation naming all of
the nominees for director or specifying the size of the increased board of
directors at least 70 days prior to the first anniversary of the preceding
year's annual meeting, a stockholder's notice required by this by-law shall also
be considered timely, but only with respect to nominees for any new positions
created by such increase, if it shall be delivered to the Secretary at the
principal executive offices of the Corporation not later than the close of
business on the 10th day following the day on which such public announcement is
first made by the Corporation.

               (B)   Only such business shall be conducted at a special meeting
of stockholders as shall have been brought before the meeting pursuant to the
Corporation's notice of meeting.  Nominations of persons for election to the
board of directors may be made at a special meeting of stockholders at which
directors are to be elected pursuant to the corporation's notice of meeting (a)
by or at the direction of the board of directors or (b) provided that the board
of directors has determined that directors shall be elected at such meeting, by
any stockholder of the corporation who is a stockholder of record at the time of
giving of notice provided for in this by-law, who shall be entitled to vote at
the meeting and who complies with the notice procedures set forth in this
by-law.  In the event the corporation calls a special meeting of stockholders
for the purpose of electing one or more directors to the board of directors, any
such stockholder may nominate a person or persons (as the case may be), for
election to such position(s) as specified in the corporation's notice of
meeting, if the stockholder's notice required by paragraph (A) (2) of this
by-law shall be delivered to the Secretary at the principal executive offices of
the corporation not earlier than the close of business on the 90th day prior to
such special meeting and not later than the close of business on the later of
the 60th day prior to such special meeting or the 10th day following the day on
which public announcement is first made of the date of the special meeting and

of the nominees proposed by the board of directors to be elected at such
meeting.  In no event shall the public announcement of an adjournment of a
special meeting commence a new time period for the giving of a stockholder's
notice as described above.

               (C)   (1)  Only such persons who are nominated in accordance with
the procedures set forth in this by-law shall be eligible to serve as directors
and only such business shall be conducted at a meeting of stockholders as shall
have been brought before the meeting in accordance with the procedures set forth
in this by-law.  Except as otherwise provided by law, the certificate of
incorporation or these by-laws, the Chairman of the meeting shall have the power
and duty to determine whether a nomination or any business proposed to be
brought before the meeting was made or proposed, as the case may be, in
accordance with the procedures set forth in this by-law and, if any proposed
nomination or business is not in compliance with this by-law, to declare that
such defective proposal or nomination shall be disregarded.

                     (2)  For purposes of this by-law, "public announcement"
shall mean disclosure in a press release reported by the Dow Jones News Service,
Associated Press or comparable national news service or in a document publicly
filed by the corporation with the Securities and Exchange Commission pursuant to
Section 13, 14 or 15(d) of the Exchange Act.

                     (3)  Notwithstanding the foregoing provisions of this
by-law, a stockholder shall also comply with all applicable requirements of the
Exchange Act and the rules and regulations thereunder with respect to the
matters set forth in this by-law. Nothing in this by-law shall be deemed to
affect any rights (i) of stockholders to request inclusion of proposals in the
corporation's proxy statement pursuant to Rule 14a-8 under the Exchange Act or
(ii) of the holders of any series of Preferred Stock to elect directors under
specified circumstances.

     Section 8.  Except as otherwise provided by law or by the certificate of
incorporation, the holders of a  majority  of the outstanding shares of the
corporation entitled to vote generally in the election of directors (the "Voting
Stock"), represented in person or by proxy, shall constitute a quorum at a
meeting of stockholders, except that when specified business is to be voted on
by a class or series of stock voting as a class, the holders of a majority of
the shares of such class or series shall constitute a quorum of such class or
series for the transaction of such business.  The Chairman of the meeting or a
majority of the shares so represented may adjourn the meeting from time to time,
whether or not there is such a quorum.  No notice of the time and place of
adjourned meetings need by given except as required by law.  The stockholders
present at a duly called meeting at which a quorum is present may continue to
transact business until adjournment, notwithstanding the withdrawal of enough
stockholders to leave less than a quorum.  The Chairman of the meeting shall fix
and announce at the meeting the date and time of the opening and the closing of
the polls for each matter upon which the stockholders will vote at a meeting.

     Section 9.  When a quorum is present at any meeting, the vote of the
holders of a majority of the stock having voting power present in person or
represented by proxy shall decide any question brought before such meeting,
unless the question is one upon which by express provision of the statutes or of
the certificate of incorporation, a different vote is required in which case
such express provision shall govern and control the decision of such question.

     Section 10.  Unless otherwise provided in the certificate of incorporation
or certificates of designations, and preferences, each stockholder shall at
every meeting of the stockholders be entitled to one vote in person or by proxy
for each share of the capital stock having voting power held by such
stockholder, but no proxy shall be voted on after three years from its date,
unless the proxy provides for a longer period.

                                 ARTICLE III

                                  DIRECTORS

     Section 1.  The number of directors which shall constitute the whole board
shall be not less than twelve nor more than fourteen.  No director need be a
stockholder of the corporation.  Any director may be removed from office with
cause at any time by the affirmative vote of stockholders of record holding a
majority of the outstanding shares of stock of the corporation entitled to vote,
given at a meeting of the stockholders called for that purpose.

     Section 2.  The board of directors shall be divided into three classes as
nearly equal in number as possible, and no class shall include less than four
directors.  The terms of office of the directors initially classified shall be
as follows: that of Class I shall expire at the next annual meeting of
stockholders in 1972, Class II at the second succeeding annual meeting of
stockholders in 1973 and Class III at the third succeeding annual meeting of
stockholders in 1974.  The foregoing notwithstanding, each director shall serve
until his successor shall have been duly elected and qualified, unless he shall
resign, become disqualified, disabled or shall otherwise be removed.  Whenever a
vacancy occurs on the board of directors, a majority of the remaining directors
have the power to fill the vacancy by electing a successor director to fill that
portion of the unexpired term resulting from the vacancy.

     Section 3.  The business of the corporation shall be managed by its board
of directors which may exercise all such powers of the corporation and do all
such lawful acts and things as are not by statute or by the certificate of
incorporation or by these by-laws directed or required to be exercised or done
by the stockholders.

     Section 4.  The board of directors shall choose a chairman of the board of
directors who shall preside at all meetings of stockholders and directors.

                   MEETINGS OF THE BOARD OF DIRECTORS

     Section 5.  The board of directors of the corporation may hold meetings,
both regular and special, either within or without the State of Delaware.

     Section 6.  Regular meetings of the board of directors may be held without
notice at such time and at such place as shall from time to time be determined
by the board.

     Section 7.  Special meetings of the board may be called by the president or
chairman of the board on three days' notice to each director, either personally
or by mail or by telegram; special meetings shall be called by the president or
secretary in like manner and on like notice on the written request of two
directors.

     Section 8.  At all meetings of the board one-third of the board of
directors shall constitute a quorum for the transaction of business and the act
of a majority of the directors present at any meeting at which there is a quorum
shall be the act of the board of directors, except as may be otherwise
specifically provided by statute or by the certificate of incorporation.  If a
quorum shall not be present at any meeting of the board of directors, the
directors present thereat may adjourn the meeting from time to time, without
notice other than announcement at the meeting, until a quorum shall be present.

     Section 9.  Unless otherwise restricted by the certificate of incorporation
or these by-laws, any action required or permitted to be taken at any meeting of
the board of directors or of any committee thereof may be taken without a
meeting, if all members of the board or committee, as the case may be, consent
thereto in writing, and the writing or writings are filed with the minutes of
proceedings of the board or committee.

                            COMMITTEES OF DIRECTORS

     Section 10.  The board of directors, may, by resolution passed by a
majority of the whole board, designate one or more committees, each committee to
consist of one or more of the directors of the corporation.  The board may
designate one or more directors as alternate members of any committee, who may
replace any absent or disqualified member of any meeting of the committee.  In
the absence or disqualification of a member of a committee, the member or
members thereof present at any meeting and not disqualified from voting, whether
or not he or they constitute a quorum, may unanimously appoint another member of
the board of directors to act at the meeting in the place of any such absent or
disqualified member.  Any such committee, to the extent provided in the
resolution of the board of directors, shall have and may exercise all the powers
and authority of the board of directors in the management of the business and
affairs of the corporation, and may authorize the seal of the corporation to be
affixed to all papers which may require it; but no such committee shall have the
power or authority in reference to amending the certificate of incorporation,
adopting an agreement of merger or consolidation, recommending to the
stockholders the sale, lease or exchange of all or substantially all of the
corporation's property and assets, recommending to the stockholders a
dissolution of the corporation or a revocation of a dissolution, or amending the
by-laws of the corporation; and, unless the resolution or the certificate of
incorporation expressly so provide, no such committee shall have the power or
authority to declare a dividend or to authorize the issuance of stock.  Such
committee or committees shall have such name or names as may be determined from
time to time by resolution adopted by the board of directors.

     Section 11.  Each committee shall keep regular minutes of its meetings and
report the same to the board of directors when required.

                           COMPENSATION OF DIRECTORS

     Section 12.  Unless otherwise restricted by the certificate of
incorporation, the board of directors shall have the authority to fix the
compensation of directors.  The directors may be paid their expenses, if any, of
attendance at each meeting of the board of directors and may be paid a fixed sum
for attendance at each meeting of the board of directors or a stated salary as
director.  No such payment shall preclude any director from serving the
corporation in any other capacity and receiving compensation therefor. Members
of special or standing committees may be allowed like compensation for attending
committee meetings.

                                ARTICLE IV

                                 NOTICES

     Section 1.  Whenever, under the provisions of the statutes or of the
certificate of incorporation or of these by-laws, notice is required to be given
to any director or stockholder, it shall not be construed to mean personal
notice, but such notice may be given in writing, by mail addressed to such
director or stockholder, at his address as it appears on the records of the
corporation, with postage thereon prepaid, and such notice shall be deemed to be
given at the time when the same shall be deposited in the United States mail.
Notice to directors may also be given by telegram.

     Section 2.  Whenever any notice is required to be given under the
provisions of the statutes or of the certificate of incorporation or of these
by-laws, a waiver thereof in writing, signed by the person or persons entitled
to said notice, whether before or after the time stated therein, shall be deemed
equivalent thereto.

                               ARTICLE V

                               OFFICERS

     Section 1.  The officers of the corporation shall be chosen by the board of
directors and shall be a chairman of the board of directors, a president, one or
more vice-presidents, a secretary and a treasurer.  The board of directors may
also choose additional vice-presidents, and one or more assistant secretaries
and assistant treasurers. Any number of offices may be held by the same person,
unless the certificate of incorporation or these by-laws otherwise provide.

     Section 2.  The board of directors at its first meeting after each annual
meeting of stockholders shall choose a chairman of the board of directors, a
president, one or more vice-presidents, a secretary and a treasurer.

     Section 3.  The board of directors may appoint such other officers and
agents as it shall deem necessary who shall hold their offices for such terms
and shall exercise such powers and perform such duties as shall be determined
from time to time by the board.

     Section 4.  The salaries of all officers and agents of the corporation
shall be fixed by the board of directors.

     Section 5.  The officers of the corporation shall hold office until their
successors are chosen and qualify.  Any officer elected or appointed by the
board of directors may be removed at any time by the affirmative vote of a
majority of the board of directors. Any vacancy occurring in any office of the
corporation shall be filled by the board of directors.

                       THE CHAIRMAN OF THE BOARD

     Section 6.  The chairman of the board of directors shall be the chief
executive officer of the corporation.  He shall preside at all meetings of
stockholders and directors. Except where by law the signature of the president
is required, the chairman of the board of directors shall possess the same power
as the president to sign all certificates, contracts, and other instruments of
the corporation which may be authorized by the board of directors.  During the
absence or disability of the president, he shall exercise all powers and
discharge all the duties of the president.

                            THE PRESIDENT

     Section 7.  The president shall be the chief operating officer of the
corporation.  In the absence of the chairman of the board of directors, the
president shall preside at all meetings of the stockholders and the board of
directors, shall have general and active management of the business of the
corporation and shall see that all orders and resolutions of the board of
directors are carried into effect.

     The president shall execute bonds, mortgages and other contracts requiring
a seal, under the seal of the corporation, except where required or permitted by
law to be otherwise signed and executed and except where the signing and
execution thereof shall be expressly delegated by the board of directors to some
other officer or agent of the corporation.

                           THE VICE PRESIDENTS

     Section 8.  In the absence of the chairman of the board of directors or the
president or in the event of his inability or refusal to act, the vice president
(or in the event there be more than one vice president, the vice presidents in
the order designated, or in the absence of any designation, then in the order of
their election) shall perform the duties of the chairman of the board of
directors or the president, and when so acting, shall have all the powers of and
be subject to all the restrictions upon the chairman of the board of directors
or the president.  The vice presidents shall perform such other duties and shall
have other powers as the board of directors may from time to time prescribe.

                  THE SECRETARY AND ASSISTANT SECRETARIES

     Section 9.  The secretary shall attend all meetings of the board of
directors and all meetings of the stockholders and record all proceedings of the
meetings of the corporation and of the board of directors in a book to be kept
for that purpose and shall perform like duties for the standing committees when
required.  He shall give, or cause to be given, notice of all meetings of the
stockholders and special meetings of the board of directors, and shall perform
such other duties as may be prescribed by the board of directors, the chairman
of the board of directors or the president, under whose supervision he shall be.
He shall have custody of the corporate seal of the corporation and he, or an
assistant secretary, shall have authority to affix the same to any instrument
requiring it and when so affixed, it may be attested by his signature or by the
signature of such assistant secretary.  The board of directors may give general
authority to any other officer to affix the seal of the corporation and to
attest the affixing by his signature.

     Section 10.  The assistant secretary, or if there be more than one, the
assistant secretaries, in the order determined by the board of directors (or if
there be no such determination, then in the order of their election), shall, in
the absence of the secretary or in the event of his inability or refusal to act,
perform the duties and exercise the powers of the secretary and shall perform
such other duties and have such other powers as the board of directors may from
time to time prescribe.

                  THE TREASURER AND ASSISTANT TREASURERS

     Section 11.  The treasurer shall have the custody of the corporate funds
and securities and shall keep full and accurate accounts of receipts and
disbursements in books belonging to the corporation and shall deposit all monies
and other valuable effects in the name and to the credit of the corporation in
such depositories as may be designated by the board of directors.

     Section 12.  He shall disburse the funds of the corporation as may be
ordered by the board of directors, taking proper vouchers for such
disbursements, and shall render to the chairman of the board of directors and
the president and the board of directors, at its regular meetings, or when the
board of directors so requires, an account of all his transactions as treasurer
and of the financial condition of the corporation.

     Section 13.  If required by the board of directors, he shall give the
corporation a bond (which shall be renewed every six years) in such sum and with
such surety or sureties as shall be satisfactory to the board of directors for
the faithful performance of the duties of his office and for the restoration to
the corporation, in case of his death, resignation, retirement or removal from
office, of all books, papers, vouchers, money and other property of whatever
kind in his possession or under his control belonging to the corporation.

     Section 14.  The assistant treasurer, or if there shall be more than one,
the assistant treasurers in the order determined by the board of directors (or
if there be no such determination, then in the order of their election), shall,
in the absence of the treasurer or in the event of his inability or refusal to
act, perform the duties and exercise the powers of the treasurer and shall
perform such other duties and have such other powers as the board of directors
may from time to time prescribe.

                          INDEMNIFICATION PROVISION

     Section 15.  The corporation shall indemnify any person who was or is a
party or is threatened to be made a party to any threatened pending or completed
action, suit or proceeding by reason of the fact that he is or was a director,
officer, employee or an agent of the corporation or is or was serving at the
request of the corporation as a director, officer, employee or agent of another
corporation, partnership, joint venture, trust or other enterprise, against all
expenses (including attorney's fees), judgments, fines and amounts paid in
settlement actually and reasonably incurred by him in connection with the
defense or settlement of such action, suit or proceeding, to the fullest extent
and in the manner set forth in and permitted by the General Corporation Law of
the State of Delaware, as from time to time in effect, and any other applicable
law, as from time to time in effect.  Such right of indemnification shall not be
deemed exclusive of any other rights to which such director, officer, employee
or agent and shall inure to the benefit of the heirs, executors and
administrators of each such person.

     The foregoing provisions of this Article shall be deemed to be a contract
between the corporation and each director, officer, employee or agent who serves
in such capacity at any time while this Article, and the relevant provisions of
the General Corporation Law of the State of Delaware and other applicable law,
if any, are in effect, and any repeal or modification thereof shall not affect
any rights or obligations then existing with respect to any state of facts then
or theretofore existing or any action, suit or proceeding theretofore or
thereafter brought or threatened based in whole or in part upon any such state
of facts.

                                ARTICLE VI

                           CERTIFICATES OF STOCK

     Section 1.  Every holder of stock in the corporation shall be entitled to
have a certificate, signed by, or in the name of the corporation by the chairman
of the board of directors, the president or a vice president and the treasurer
or an assistant treasurer, or the secretary or an assistant secretary of the
corporation, certifying the number of shares owned by him in the corporation.

     Certificates may be issued for partly paid shares and in such case upon the
face or back of the certificates issued to represent any such partly paid
shares, the total amount of the consideration to be paid therefor, and the
amount paid thereon shall be specified.

     If the corporation shall be authorized to issue more than one class of
stock or more than one series of any class, the powers, designations,
preferences and relative, participating, optional or other special rights of
each class of stock or series thereof and the qualifications, limitations or
restrictions of such preferences and/or rights shall be set forth in full or
summarized on the face or back of the certificate which the corporation shall
issue to represent such class or series of stock, provided that, except as
otherwise provided in Section 202 of the General Corporation Law of Delaware, in
lieu of the foregoing requirements, there may be set forth on the face or back
of the certificate which the corporation shall issue to represent such class or
series or stock, provided that, except as otherwise provided in Section 202 of
the General Corporation Law of Delaware, in lieu of the foregoing requirements,
there may be set forth on the face or back of the certificate which the
corporation shall issue to represent such class or series of stock, a statement
that the corporation will furnish without charge to each stockholder who so
requests the powers, designations, preferences and relative, participating,
optional or other special rights of each class of stock or series thereof and
the qualifications, limitations or restrictions of such preferences and/or
rights.

     Section 2.  Where a certificate is countersigned (1) by a transfer agent
other than the corporation or its employee, or (2) by a registrar other than the
corporation or its employee, any other signature on the certificate may be a
facsimile.  In case any officer, transfer agent or registrar who has signed or
whose facsimile signature has been placed upon a certificate shall have ceased
to be such officer, transfer agent or registrar before such certificate is
issued, it may be issued by the corporation with the same effect as if he were
such officer, transfer agent or registrar at the date of issue.

                            LOST CERTIFICATES

     Section 3.  The board of directors may direct a new certificate or
certificates to be issued in place of any certificate or certificates
theretofore issued by the corporation alleged to have been lost, stolen or
destroyed, upon the making of an affidavit of that fact by the person claiming
the certificate of stock to be lost, stolen or destroyed.  When authorizing such
issue of a new certificate or certificates, the board of directors may, in its
discretion and as a condition precedent to the issuance thereof, require the
owner of such lost, stolen or destroyed certificate or certificates, or his
legal representative, to advertise the same in such manner as it shall require
and/or to give the corporation a bond in such sum as it may direct as indemnity
against any claim that may be made against the corporation with respect to the
certificate alleged to have been lost, stolen or destroyed.

                            TRANSFERS OF STOCK

     Section 4.  Upon surrender to the corporation or the transfer agent of the
corporation of a certificate for shares duly endorsed or accompanied by proper
evidence of succession, assignment or authority to transfer, it shall be the
duty of the corporation to issue a new certificate to the person entitled
thereto, cancel the old certificate and record the transaction upon its books.

                            FIXING RECORD DATE

     Section 5.  In order that the corporation may determine the stockholders
entitled to notice of or to vote at any meeting of stockholders or any
adjournment thereof, or to express consent to corporate action in writing
without a meeting, or entitled to receive payment of any dividend or other
distribution or allotment of any rights, or entitled to exercise any rights in
respect of any change, conversion or exchange of stock or for the purpose of any
other lawful action, the board of directors may fix, in advance, a record date,
which shall not be more than sixty nor less than ten days before the date of
such meeting, nor more than sixty days prior to any other action.  A
determination of stockholders of record entitled to notice of or to vote at a
meeting of stockholders shall apply to any adjournment of the meeting, provided,
however, that the board of directors may fix a new record date for the adjourned
meeting.

                          REGISTERED STOCKHOLDERS

     Section 6.  The corporation shall be entitled to recognize the exclusive
right of a person registered on its books as the owner of shares to receive
dividends, and to vote as such owner, and to hold liable for calls and
assessments a person registered on its books as the owner of shares, and shall
not be bound to recognize any equitable or other claim to or interest in such
share or shares on the part of any other person, whether or not it shall have
express or other notice thereof, except as otherwise provided by the laws of
Delaware.

                              ARTICLE VII

                           GENERAL PROVISIONS

                               DIVIDENDS

     Section 1.  Dividends upon the capital stock of the corporation, subject to
the provisions of the certificate of incorporation, if any, may be declared by
the board of directors at any regular or special meeting, pursuant to law.
Dividends may be paid in cash, in property, or in shares of the capital stock,
subject to the provisions of the certificate of incorporation.

     Section 2.  Before payment of any dividend, there may be set aside out of
any funds of the corporation available for dividends such sum or sums as the
directors from time to time, in their absolute discretion, think proper as a
reserve or reserves to meet contingencies, or for equalizing dividends, or for
repairing or maintaining property of the corporation, or for such other purpose
as the directors shall think conducive to the interest of the corporation, and
the directors may modify or abolish any such reserve in the manner in which it
was created.

                             ANNUAL STATEMENT

     Section 3.  The board of directors shall present at each annual meeting,
and at any special meeting of the stockholders when called for by vote of the
stockholders, a full and clear statement of the business and condition of the
corporation.

                                  CHECKS

     Section 4.  All checks or demands for money and notes of the corporation
shall be signed by such officer or officers or such other person or persons as
the board of directors may from time to time designate.

                               FISCAL YEAR

     Section 5.  The fiscal year of the corporation shall be fixed by resolution
of the board of directors.

                                  SEAL

     Section 6.  The corporate seal shall have inscribed thereon the name of the
corporation, the year of its organization and the words, "Corporate Seal,
Delaware".  The seal may be used by causing it or a facsimile thereof to be
impressed or affixed or reproduced or otherwise.

                                 ARTICLE VIII

                                  AMENDMENTS

     Section 1.  These by-laws may be altered, amended, repealed, or new by-laws
may be adopted by the stockholders or by the board of directors, when such power
is conferred upon the board of directors by the certificate of incorporation, at
any regular meeting of the stockholders or of the board of directors or at any
special meeting of the stockholders or of the board of directors if notice of
such alteration, amendment, repeal or adoption of new by-laws be contained in
the notice of such special meeting.


AMENDMENT TO RIGHTS AGREEMENT                                     Exhibit 4.1

           AMENDMENT, dated as of November 8, 1994, to the Rights Agreement
between Instrument Systems Corporation, a Delaware corporation (the "Company"),
and American Stock Transfer Company, as Rights Agent (the "Rights Agent"), dated
as of April 2, 1986 (the "Rights Agreement").

           The Company and the Rights Agent have heretofore executed and entered
into the Rights Agreement.  Pursuant to Section 26 of the Rights Agreement, the
Company and the Rights Agent may from time to time supplement or amend the
Rights Agreement in accordance with the provisions of Section 26 thereof.  All
acts and things necessary to make this Amendment a valid agreement, enforceable
according to its terms have been done and performed, and the execution and
delivery of this Amendment by the Company and the Rights Agent have been in all
respects duly authorized by the Company and the Rights Agent.

           In consideration of the foregoing and the mutual agreements set forth
herein, the parties hereto agree as follows:

           1.   Section 1(a) of the Rights Agreement is hereby modified and
amended to read in its entirety as follows:

     (a)   "Acquiring Person" shall mean any Person (as such term is hereinafter
defined) who or which, together with all Affiliates and Associates (as such
terms are hereinafter defined) of such Person, shall be the Beneficial Owner (as
such term is hereinafter defined) of 15% or more of the Common Stock of the
Company then outstanding, but shall not include the Company, any wholly owned
subsidiary of the Company, any employee benefit plan of the Company or any
wholly owned subsidiary of the Company, or any entity holding shares of Common
Stock for or pursuant to the terms of any such plan.  Notwithstanding the
foregoing, no Person shall become an "Acquiring Person" as the result of an
acquisition of Common Stock by the Company which, by reducing the number of
shares outstanding, increases the proportionate number of shares beneficially
owned by such Person to 15% or more of the Common Stock of the Company then
outstanding; provided, however, that if a Person shall become the Beneficial
Owner of 15% or more of the Common Stock of the Company then outstanding by
reason of share purchases by the Company and shall, after such share purchases
by the Company, become the Beneficial Owner of any additional Common Stock of
the Company, then such Person shall be deemed to be an "Acquiring Person".

           2.   Section 1(c)(ii) of the Rights Agreement is hereby modified and
amended to read in its entirety as follows:

     (ii)  which such Person or any of such Person's Affiliates or Associates
has (A) the right to acquire (whether such right is exercisable immediately or
only after the passage of time) pursuant to any agreement, arrangement or
understanding (other than customary agreements with and between underwriters and
selling group members with respect to a bona fide public offering of
securities), or upon the exercise of conversion rights, exchange rights, rights
(other than these Rights), warrants or options, or otherwise; provided, however,
that a Person shall not be deemed the Beneficial Owner of, or to beneficially
own, securities tendered pursuant to a tender or exchange offer made by or on
behalf of such Person or any of such Person's Affiliates or Associates until
such tendered securities are accepted for purchase or exchange; or (B) the right
to vote pursuant to any agreement, arrangement or understanding; provided,
however, that a Person shall not be deemed the Beneficial Owner of, or to
beneficially own, any security if the agreement, arrangement or understanding to
vote such security (1) arises solely from a revocable proxy or consent given to
such Person in response to a public proxy or consent solicitation made pursuant

to, and in accordance with, the applicable rules and regulations of the Exchange
Act and (2) is not also then reportable on Schedule 13D under the Exchange Act
(or any comparable or successor report); or

           3.   Section 1(c)(iii) of the Rights Agreement is hereby modified and
amended to read in its entirety as follows:

     (iii) which are beneficially owned, directly or indirectly, by any other
Person with which such Person or any of such Person's Affiliates or Associates
has any agreement, arrangement or understanding (other than customary agreements
with and between underwriters and selling group members with respect to a bona
fide public offering of securities) for the purpose of acquiring, holding,
voting (except to the extent contemplated by the proviso to Section 1(c)(ii)(B))
or disposing of any securities of the Company.

           4.   Section 1(c) of the Rights Agreement is hereby modified and
amended by adding the following at the end thereof:

     Notwithstanding anything in this definition of Beneficial Ownership to the
contrary, the phrase "then outstanding", when used with reference to a Person's
Beneficial Ownership of securities of the Company, shall mean the number of such
securities then issued and outstanding together with the number of such
securities not then actually issued and outstanding which such Person would be
deemed to own beneficially hereunder.

           5.   Section 1(j) of the Rights Agreement is hereby modified and
amended to read in its entirety as follows:

     (j)   "Substantial Block" shall mean a number of shares of the Common Stock
which equals or exceeds 15% of the number of shares of the Common Stock then
outstanding.

           6.   Section 1(k) of the Rights Agreement is hereby modified and
amended to read in its entirety as follows:

     (k)   "Triggering Event" shall mean any event described in Section
11(a)(ii) or Section 13(a).

           7.   Section 3(a) of the Rights Agreement is hereby modified and
amended by deleting the first two sentences thereof  and by substituting
therefor the following:

     (a)   Until the earlier of (i) the tenth day after the Shares Acquisition
Date or (ii) the tenth business day (or such later date as may be determined by
action of the Board of Directors prior to such time as any Person becomes an
Acquiring Person) after the date of the commencement by any Person (other than
the Company, any wholly owned subsidiary of the Company, any employee benefit
plan of the Company or of any wholly owned subsidiary of the Company or any
Person holding Common Stock for or pursuant to the terms of any such plan) or
the date of an announcement of an intention by any Person to commence, a tender
or exchange offer the consummation of which would result in any Person becoming
the Beneficial Owner of Common Stock aggregating 15% or more of the then
outstanding Common Stock (including any such date which is after the date of
this Agreement and prior to the issuance of the Rights; the earlier of such
dates being herein referred to as the "Distribution Date"), (x) the Rights will
be evidenced (subject to the provisions of Section 3(b) hereof) by the
certificates for Common Stock registered in the names of the holders thereof
(which certificates shall also be deemed to be Right Certificates) and not by
separate Right Certificates, and (y) the right to receive Right Certificates

will be transferable only in connection with the transfer of Common Stock.  As
soon as practicable after the Distribution Date, the Company will prepare and
execute, the Rights Agent will countersign, and the Company will send or cause
to be sent (and the Rights Agent will, if requested, send) by first-class,
insured, postage-prepaid mail, to each record holder of Common Stock as of the
close of business on the Distribution Date, at the address of such holder shown
on the records of the Company, a Right Certificate, substantially in the form of
Exhibit A hereto (the "Right Certificate"), evidencing one Right for each share
of Common Stock so held.

           8.   Section 3(c) of the Rights Agreement is hereby modified and
amended to provide that this legend contained in such Section shall read in its
entirety as follows:

This certificates also evidences and entitles the holder hereof to certain
Rights as set forth in a Rights Agreement between INSTRUMENT SYSTEMS CORPORATION
and AMERICAN STOCK TRANSFER COMPANY, Rights Agent, dated as of April 2, 1986, as
amended (the "Rights Agreement"), the terms of which are hereby incorporated
herein by reference and a copy of which is on file at the principal executive
offices of INSTRUMENT SYSTEMS CORPORATION.  Under certain circumstances, as set
forth in the Rights Agreement, such Rights will be evidenced by separate
certificates and will no longer be evidenced by this certificate.  INSTRUMENT
SYSTEMS CORPORATION will mail to the holder of this certificate a copy of the
Rights Agreement (as in effect on the date of mailing) without charge promptly
after receipt of a written request therefor. Rights which are or were
beneficially owned by Acquiring Persons or their Affiliates or Associates (as
such terms are defined in the Rights Agreement) and any subsequent holder of
such Rights will be null and void.

           9.   Section 3(c) of the Rights Agreement is hereby further modified
and amended by adding the following at the end thereof:

In addition, subject to Section 11(a)(ii) hereof, in connection with the
issuance of Common Stock on or following the Distribution Date and prior to the
Final Expiration Date, the Company shall, with respect to Common Stock so issued
upon the exercise, conversion or exchange of options, warrants, securities,
notes or debentures issued by the Company prior to the Distribution Date (other
than shares issued upon exercise or exchange of the Rights), issue Rights
Certificates representing the appropriate number of Rights in connection with
such issuance; provided, however, that, (i)  no such Rights Certificate shall be
issued if, and to the extent that, the Company shall be advised by counsel that
such issuance would create a significant risk of material adverse tax
consequences to the Company or the Person to whom such Rights Certificate would
be issued, and (ii) no such Rights Certificate shall be issued if, and to the
extent that, appropriate adjustment (giving effect to the provisions of Sections
11(a)(ii) and 13 hereto) shall otherwise have been made in lieu of the issuance
thereof.

          10.   Section 4(b) of the Rights Agreement is hereby amended and
modified to provide that the legend contained therein shall read in its entirety
as follows:

The Rights represented by this Right Certificate are or were beneficially owned
by a Person who was or became an Acquiring Person or an Affiliate or an
Associate of an Acquiring Person (as such terms are defined in the Rights
Agreement).  This Right Certificate and the Rights represented hereby are null
and void.

          11.   Section 6 of the Rights Agreement is hereby modified and amended
by deleting the first sentence thereof and by substituting therefor the
following:

     Section 6.  Transfer, Split Up, Combination and Exchange of Right
Certificates; Mutilated, Destroyed, Lost or Stolen Right Certificates.  Subject
to the provisions of Section 14 hereof, at any time after the close of business
on the Distribution Date, and at or prior to the close of business on the
earlier of the Expiration Date or Final Expiration Date (as such terms are
defined in Section 7 hereof), any Right Certificate or Right Certificates (other
than Right Certificates representing Rights that have become void pursuant to
Section 11(a)(ii) hereof or that may have been exchanged pursuant to Section 23A
hereof) may be transferred, split up, combined or exchanged for another Right
Certificate or Right Certificates, entitling the registered holder to purchase a
like number of shares of Common Stock as the Right Certificate or Right
Certificates surrendered then entitled such holder to purchase.

          12.   Section 7(a) of the Rights Agreement is hereby modified and
amended by adding the words ", or (iii) the time at which the Rights are
exchanged as provided in Section 23A hereof" immediately prior to the words ";
provided, however, that" in such Section.

          13.    Section 7(c) of the Rights Agreement is hereby amended by
deleting the last sentence thereof.

          14.    Section 11(a)(ii) of the Rights Agreement is hereby modified 
and amended to read in its entirety as follows:

     (ii)  In the event any Person shall become an Acquiring Person, each holder
of a Right shall thereafter have a right to receive, upon exercise thereof at a
price equal to the then current Purchase Price multiplied by the number of
halves of a share of Common Stock for which a Right is then exercisable, in
accordance with the terms of this Agreement, such number of shares of Common
Stock of the Company as shall equal the result obtained by (x) multiplying the
then current Purchase Price by the then number of halves of a share of Common
Stock for which a Right is then exercisable and dividing that product by (y) 50%
of the then current per share market price of the Company's Common Stock
(determined pursuant to Section 11(d) hereof) on the date on which any Person
shall become an Acquiring Person.  In the event that any Person shall become an
Acquiring Person and the Rights shall then be outstanding, the Company shall not
take any action which would eliminate or diminish the benefits intended to be
afforded by the Rights.

           Notwithstanding the foregoing or anything in this Agreement to the
contrary, any Rights that are or were acquired or beneficially owned by any
Acquiring Person (or any Associate or Affiliate of such Acquiring Person) shall
be void and any holder of such Rights shall thereafter have no right to exercise
such Rights under any provision of this Agreement.  No Right Certificate shall
be issued pursuant to Section 3 that represents Rights beneficially owned by an
Acquiring Person whose Rights would be void pursuant to the preceding sentence
or any Associate or Affiliate thereof; no Right Certificate shall be issued at
any time upon the transfer of any Rights to an Acquiring Person whose Rights
would be void pursuant to the preceding sentence or any Associate or Affiliate
thereof or to any nominee of such Acquiring Person, Associate or Affiliate; and
any Right Certificate delivered to the Rights Agent for transfer to an Acquiring
Person whose Rights would be void pursuant to the preceding sentence shall be
cancelled.

          15.    Section 11(a)(iii) of the Rights Agreement is hereby deleted.

          16.    The first sentence of Section 23(a) of the Rights Agreement is
hereby modified and amended to delete the words "5:00 P.M., New York City time,
on".

          17.    Section 23(a) of the Rights Agreement is hereby further 
modified and amended by adding the following at the end thereof:

The redemption of the Rights by the Board of Directors may be made effective at
such time on such basis and with such conditions as the Board of Directors in
its sole discretion may establish.

          18.    Section 23(b) of the Rights Agreement is hereby modified and
amended by adding the following after the first sentence thereof:

     The Company shall promptly give public notice of any such redemption;
     provided, however, that the failure to give, or any defect in, any such
     notice shall not affect the validity of such redemption.

          19.    The Rights Agreement is hereby modified and amended to add a
new Section 23A thereto to read in its entirety as follows:

              Section 23A.  Exchange.  (a) The Board of Directors of
the Company may, at its option, at any time after any Person becomes an
Acquiring Person, exchange all or part of the then outstanding and exercisable
Rights (which shall not include Rights that have become void pursuant to the
provisions of Section 11(a)(ii) hereof) for Common Stock at an exchange ratio of
one share of Common Stock per Right, appropriately adjusted to reflect any stock
split, stock dividend or similar transaction occurring after the date hereof
(such exchange ratio being hereinafter referred to as the "Exchange Ratio").
Notwithstanding the foregoing, the Board of Directors shall not be empowered to
effect such exchange at any time after any Person (other than the Company, any
wholly owned subsidiary of the Company, any employee benefit plan of the Company
or any such subsidiary, or any entity holding Common Stock for or pursuant to
the terms of any such plan), together with all Affiliates and Associates of such
Person, becomes the Beneficial Owner of 50% or more of the Common Stock then
outstanding.

           (b) Immediately upon the action of the Board of Directors of the
Company ordering the exchange of any Rights pursuant to paragraph (a) of this
Section 23A and without any further action and without any notice, the right to
exercise such Rights shall terminate and the only right thereafter of a holder
of such Rights shall be to receive that number of shares of Common Stock equal
to the number of such Rights held by such holder multiplied by the Exchange
Ratio.  The Company shall promptly give public notice of any such exchange;
provided, however, that the failure to give, or any defect in, such notice shall
not affect the validity of such exchange.  The Company promptly shall mail a
notice of any such exchange to all of the holders of such Rights at their last
addresses as they appear upon the registry books of the Rights Agent.  Any
notice which is mailed in the manner herein provided shall be deemed given,
whether or not the holder receives the notice.  Each such notice of exchange
will state the method by which the exchange of the Common Stock for Rights will
be effected and, in the event of any partial exchange, the number of Rights
which will be exchanged.  Any partial exchange shall be effected pro rata based
on the number of Rights (other than Rights which have become void pursuant to
the provisions of Section 11(a)(ii) hereof) held by each holder of Rights.

             (c)  In the event that there shall not be sufficient Common Stock
issued but not outstanding or authorized but unissued to permit any exchange of
Rights as contemplated in accordance with this Section 23A, the Company shall
take all such action as may be necessary to authorize additional Common Stock
for issuance upon exchange of the Rights.

             (d)  The Company shall not be required to issue fractions of shares
of Common Stock or to distribute certificates which evidence fractional shares
of Common Stock.  In lieu of such fractional shares of Common Stock, the Company
shall pay to the registered holders of the Right Certificates with regard to
which such fractional shares of Common Stock would otherwise be issuable an
amount in cash equal to the same fraction of the current market value of a whole
share of Common Stock.  For the purposes of this paragraph (d), the current
market value of a whole share of Common Stock shall be the closing price of a
share of Common Stock (as determined pursuant to the second sentence of Section
11(d) hereof) for the Trading Day immediately prior to the date of exchange
pursuant to this Section 23A.

          20.    The Rights Agreement is hereby modified and amended by deleting
the headnote to the Form of Right Certificate set forth as Exhibit A to the
Rights Agreement and replacing it with the following:

NOT EXERCISABLE AFTER MAY 2, 1996 OR EARLIER IF NOTICE OF REDEMPTION OR
EXCHANGE IS GIVEN.  THE RIGHTS ARE SUBJECT TO REDEMPTION, AT THE OPTION
OF THE COMPANY, AT $.01 PER RIGHT ON THE TERMS SET FORTH IN THE RIGHTS
AGREEMENT.  [THE RIGHTS REPRESENTED BY THIS CERTIFICATE ARE OR WERE
BENEFICIALLY OWNED BY A PERSON WHO WAS OR BECAME AN ACQUIRING
PERSON OR AN ASSOCIATE OR AFFILIATE OF AN ACQUIRING PERSON (AS SUCH
TERMS ARE DEFINED IN THE RIGHTS AGREEMENT).  THIS RIGHT CERTIFICATE AND
THE RIGHTS REPRESENTED HEREBY ARE NULL AND VOID.]*

          21.    The Rights Agreement is hereby modified by deleting the sixth
paragraph of the Form of Right Certificate set forth as Exhibit A to the Rights
Agreement and substituting therefor the following:

             Subject to the provisions of the Rights Agreement, the Rights
evidenced by this Certificate (i) may be redeemed by the Company at a redemption
price of $.01 per Right or (ii) may be exchanged in whole or in part for shares
of Common Stock.

          22.   The Rights Agreement is hereby modified and amended by adding
the following to the end of the Notice forming a part of the Form of Reverse
Side of Right Certificate set forth as Exhibit A to the Rights Agreement:

     In the event the certification set forth above in the Form of Assignment or
the Form of Election to Purchase, as the case may be, is not completed, the
Company and the Rights Agent will deem the beneficial owner of the Rights
evidenced by this Right Certificate to be an Acquiring Person or an Affiliate or
Associate thereof (as defined in the Rights Agreement) and such Assignment or
Election to Purchase will not be honored.

          23.   This Amendment to the Rights Agreement shall be deemed to be a
contract made under the laws of the State of Delaware and for all purposes shall
be governed by and construed in accordance with the laws of such State
applicable to contracts to be made and performed entirely within such State.

          24.   This Amendment to the Rights Agreement may be executed in any
number of counterparts, each of which shall be an original, but such
counterparts shall together constitute one and the same instrument.  Terms not
defined herein shall, unless the context otherwise requires, have the meanings
assigned to such terms in the Rights Agreement.

          25.   In all respects not inconsistent with the terms and provisions
of this Amendment to the Rights Agreement, the Rights Agreement is hereby
ratified, adopted, approved and confirmed.  In executing and delivering this
Amendment, the Rights Agent shall be entitled to all the privileges and
immunities afforded to the Rights Agent under the terms and conditions of the
Rights Agreement.

          26.   If any term, provision, covenant or restriction of this
Amendment to the Rights Agreement is held by a court of competent jurisdiction
or other authority to be invalid, void or unenforceable, the remainder of the
terms, provisions, covenants and restrictions of this Amendment to the Rights
Agreement, and of the Rights Agreement, shall remain in full force and effect
and shall in no way be affected, impaired or invalidated.

           IN WITNESS WHEREOF, the parties hereto have caused this Amendment to
be duly executed and attested, all as of the date and year first above written.

Attest:                                INSTRUMENT SYSTEMS CORPORATION



By:                                    By:
     ------------------------------         --------------------------
     Name:                                  Name:
     Title:                                 Title:


Attest:                                AMERICAN STOCK TRANSFER COMPANY



By:                                    By:
     ------------------------------         --------------------------
     Name:                                  Name:
     Title:                                 Title: