Certificate of Incorporation
                                      of
                            Interface Systems, Inc.


         FIRST:  The name of the Corporation is INTERFACE SYSTEMS, INC.

         SECOND:  The principal office or place of business of the
Corporation in the State of Delaware is to be located at No. 100 West Tenth
Street, in the City of Wilmington, County of New Castle.  The name and post
office address of its resident agent in the State of Delaware is The
Corporation Trust Company, No. 100 West Tenth Street, Wilmington, Delaware.

         THIRD:  The nature of the business and the purpose of the
Corporation is to engage in any lawful act or activity for which
corporations may be organized under the General Corporation Law of the State
of Delaware.  The Corporation shall possess and may exercise all powers and
privileges granted by the General Corporation Law of the State of Delaware
or by any other law or by this Certificate of Incorporation, together with
any powers incident thereto, so far as such powers and privileges are
necessary or convenient to the conduct, promotion or attainment of the
business or purposes set forth in this Certificate of Incorporation.

         FOURTH:  The total number of shares of stock which may be issued is
3,000,000 shares of Common Stock, par value $0.10 per share.

                                 Common Stock

         Holders of Common Stock shall be entitled to receive such dividends
as may be declared by the Board of Directors of the Corporation from time to
time and in the event of any liquidation, dissolution or winding up of the
Corporation, whether voluntary or involuntary, to receive pro rata all the
remaining assets of the Corporation available for distribution.

         Holders of Common Stock shall have equal voting and other rights
share for share, and each holder of Common Stock is entitled to one vote per
share.

                                    General

         The Corporation shall be entitled to treat the person in whose name
any share, right or option is registered as the owner thereof, for all
purposes, and shall not be bound to recognize any equitable or other claim
to or interest in such share, right or option on the part of any other
person, whether or not the Corporation shall have notice thereof, save as
may be expressly provided by the laws of the State of Delaware.

         A director shall be fully protected in relying in good faith upon
the books of account of the Corporation or statements prepared by any of its
officers or by independent public accountants as to the value and amount of
the assets, liabilities and/or net profits of the Corporation, or any other
facts pertinent to the existence and amount of surplus or other funds from
which dividends might properly be declared and paid, or with which the
Corporation's stock might properly be purchased or redeemed.

         Without action by the stockholders, shares of stock may be issued by
the Corporation from time to time for such consideration, not less than the
par value thereof in case of shares having a par value, as may be fixed from
time to time by the Board of Directors thereof, and any and all such shares
so issued, the full consideration for which has been paid or delivered,
shall be deemed fully paid stock and liable to any further call or
assessment thereon, and the holder of such shares shall not be liable for
any further call or assessment thereon or for any further payment thereon.

         FIFTH:  All corporate powers shall be exercised by the Board of
Directors, except as otherwise provided by statute or by Certificate of
Incorporation.

         Election of directors need not be by ballot.

         Any director may be removed, whether cause shall be assigned for
such removal or not, and his place filled at any meeting of the stockholders
by the vote of a majority of the outstanding stock of the Corporation
entitled to vote.  Vacancies in the Board of Directors (except vacancies
arising from the removal of directors) andy newly created directorships may
be filled by a majority of the directors then in office, though less than a
quorum.

         IN FURTHERANCE AND NOT IN LIMITATION OF THE POWERS CONFERRED BY
STATUTE, THE BOARD OF DIRECTORS IS EXPRESSLY AUTHORIZED:

         (a)     To fix, determine and vary from time to time the amount to
                 be maintained as surplus and the amount or amounts to be set
                 apart as working capital.

         (b)     To set apart out of any of the funds of the Corporation
                 available for dividends a reserve or reserves for any proper
                 purposes and/or to abolish any such reserve in the manner in
                 which it was created.

         (c)     To make, amend, alter, change, add to or repeal bylaws for
                 the Corporation without any action on the part of the
                 stockholders.  The bylaws made by the directors may be
                 amended, altered, changed, added to or repealed by the
                 stockholders.

         (d)     To authorize and cause to be executed mortgages and liens,
                 without limit as to amount, upon the real and personal
                 property of the Corporation, including after-acquired
                 property.

         (e)     From time to time to determine whether and to what extent,
                 at what time and place, and under what conditions and
                 regulations the accounts and books of the Corporation or any
                 of them shall be open to the inspection of any stockholders;
                 and not stockholder shall have any right to inspect any
                 account or book or document of the Corporation except as
                 conferred by statute or bylaws or as authorized by a
                 resolution of the stockholders or Board of Directors.

         (f)     To authorize the payment of compensation to the directors
                 for services to the Corporation, including fees for
                 attendance at meetings of the Board of Directors, of the
                 Executive Committee, and of other committees, and to
                 determine the amount of such compensation and fees.

         SIXTH:  Any contract, transaction or act of the Corporation or of
the Board of Directors which shall be ratified by the affirmative vote of
the holders of a majority of the stock of the Corporation represented at any
meeting at which a quorum is present and which is called for that purpose,
shall be as valid and binding as though ratified by every stockholder of the
Corporation; provided, however, that any failure of the stockholders to
approve or ratify such contract, transaction or act, when and if submitted,
shall not be deemed in any way to invalidate the same or to deprive the
Corporation, its directors or officers of their right to proceed with such
contract, transaction or action.

         SEVENTH:  Any property of the Corporation not essential to the
conduct of its corporate business may be sold, leased, exchanged or
otherwise disposed of by authority of its Board of Directors, and the
Corporation may sell, lease or exchange all of its property and assets,
including its goodwill and its corporate franchises, upon such terms and
conditions and for such consideration, which may be in whole or in part
shares of stock in, and/or other securities of, any other corporation or
corporations, as its Board of Directors shall deem expedient and for the
best interests of the Corporation, when and as authorized by the affirmative
vote of the holders of a majority of the stock issued and outstanding having
voting power given at a stockholders' meeting duly called upon at least 20
days notice containing notice of the proposed sale, lease or exchange, or
when authorized by the written consent of the holders of a majority of the
voting stock issued and outstanding.

         EIGHTH:  Upon the written consent or vote of the holders of a
majority in aggregate number of shares of stock of the Corporation then
outstanding and entitled to vote, every statute of the State of Delaware (a)
increasing, diminishing, or in any way affecting the rights, powers, or
privileges of stockholders of corporations organized under the general laws
of said State, or (b) giving effect to the action taken by any part, less
than all, of the stockholders of any such corporation, shall be binding upon
the Corporation and every stockholder thereof, to the same extent as if such
statute had been in force at the date of the making, filing and recording of
this Certificate of Incorporation of the Corporation.

         NINTH:  Whenever a compromise or arrangement is proposed between
this Corporation and its creditors or any class of them and/or between this
Corporation and its stockholders or any class of them, any court of
equitable jurisdiction within the State of Delaware may on the application
in a summary way of this Corporation or of any creditor or stockholder
thereof, or on the application of any receiver or receivers appointed for
this Corporation under the provisions of Section 291 of Title 8 of the
Delaware Code or on the application of trustees in dissolution or of any
receiver or receivers appointed for this Corporation under the provisions of
Section 279 of Title 8 of the Delaware Code order a meeting of the creditors
or class of creditors, and/or of the stockholders or class of stockholders
of this Corporation, as the case may be, to be summoned in such manner as
the said court directs.  If a majority in number representing three-fourths
in value of the creditors or class of creditors, and/or of the stockholders
or class of stockholders of this Corporation, s the case may be, agree to
any compromise or arrangement and to any reorganization of this Corporation
as consequence of such compromise or arrangement, the said compromise or
arrangement and the said reorganization shall, if sanctioned by the court to
which said application has been made, be binding on all the creditors or
class of creditors, and/or on all the stockholders or class of stockholders,
of this Corporation, as the case may be, and also on this Corporation.

         TENTH:  The Corporation reserves the right to amend, alter, change
or repeal any provision contained in this Certificate of Incorporation in
the manner now or hereafter prescribed by law, and all rights and powers
conferred herein on stockholders, directors and officers are subject to this
reserved power.

                           Certificate of Amendment
                                      of
                         Certificate of Incorporation


Interface Systems, Inc., a corporation organized and existing under and by
virtue of the General Corporation Law of the State of Delaware,

DOES HEREBY CERTIFY:

FIRST:  That at a meeting of the Board of Directors of Interface Systems,
Inc. resolutions were duly adopted setting forth a proposed amendment of the
Certificate of Incorporation of said corporation, declaring said amendment
to be advisable and calling a meeting of the shareholders of said
corporation for consideration thereof.  The resolution setting forth the
proposed amendment is as follows:


         RESOLVED, that the Certificate of Incorporation of this corporation
         be amended by changing the first paragraph of Article Fourth
         thereof, so that, as amended, the first paragraph of said Article
         shall be and read as follows:

         "FOURTH:  The total number of shares of stock which the Corporation
         shall have authority to issue is Eight Million (8,000,000) shares of
         Common Stock, par value, $.10 per share."

SECOND:  That thereafter, at the 1984 Annual Meeting of the Shareholders of
said corporation duly called and held upon notice in accordance with Section
222 of the General Corporation Law of the State of Delaware, the necessary
number of shares as required by statute were voted in favor of the
amendment.

THIRD:  That said amendment was duly adopted in accordance with the
provisions of Section 242 of the General Corporation Law of the State of
Delaware.

FOURTH:  That the capital of said corporation shall not be reduced under or
by reason of said amendment.

IN WITNESS WHEREOF, said Interface Systems, Inc. has caused this certificate
to be signed by Carl L. Bixby, its President, and Thomas E. Armstrong, its
Secretary, this 31st day of May, 1984.


                                  BY: /S/ Carl L. Bixby
                                      -----------------------------
                                      Carl L. Bixby, President


                             ATTEST: /S/ Thomas E. Armstrong
                                     ------------------------------
                                     Thomas E. Armstrong, Secretary   
 

                           Certificate of Amendment
                                      of
                         Certificate of Incorporation


INTERFACE SYSTEMS, INC., a corporation organized and existing under and by
virtue of the General Corporation Law of the State of Delaware,

DOES HEREBY CERTIFY:

FIRST:  That at a meeting of the Board of Directors of Interface Systems,
Inc. resolution were duly adopted setting forth amendments of the
Certificate of Incorporation of said corporation, declaring said amendments
to be advisable and calling a meeting of the shareholders of said
corporation for consideration thereof.  The resolutions setting forth the
proposed amendments are as follows:

         RESOLVED, That the Certificate of Incorporation of this corporation
         by amended by changing Article FIFTH thereof, so that, as amended,
         the Article shall be and read in its entirety as follows:

         "FIFTH:  All corporation powers shall be exercised by the Board of
         Directors, except as otherwise provided by statute or by Certificate
         of Incorporation.

         Election of directors need not be by ballot.

         IN FURTHERANCE AND NOT IN LIMITATION OF THE POWERS CONFERRED BY
         STATUTE, THE BOARD OF DIRECTORS IS EXPRESSLY AUTHORIZED:


         (a)  To fix, determine and vary from time to time the amount to be
         maintained as surplus and the amount or amounts to be set apart as
         working capital.

         (b)  To set apart out of any of the funds of the Corporation
         available for dividends a reserve or reserves for any proper purpose
         and/or to abolish any such reserve in the manner in which it was
         created.

         (c)  To make, amend, alter, change, add to or repeal bylaws for the
         Corporation without any action on the part of the stockholders.  The
         bylaws may be amended, altered, changed, added to or repealed by the
         stockholders only as provided in the bylaws.

         (d)  To authorized and cause to be executed mortgages and liens,
         without limit as to amount, upon the real and personal property of
         the Corporation, including after-acquired property.

         (e)  From time to time to determine whether and to what extent, at
         what time and place, and under what conditions and regulations the
         accounts and books of the Corporation or any of them shall be open
         to the inspection of any stockholders; and no stockholder shall have
         any right to inspect any account or book or document of the
         Corporation except as conferred by statute or bylaws or as
         authorized by a resolution of the stockholders or Board of
         Directors.

         (f)  To authorize the payment of compensation to the directors for
         services to the Corporation, including fees for attendance at
         meetings of the Board of Directors, of the Executive Committee, and
         of other committees, and to determine the amount of such
         compensation and fees." 

         FURTHER RESOLVED, That the Certificate of Incorporation of this
         corporation be amended by adding Article ELEVENTH so that said
         Article shall be and read in its entirety as follows:

         "ELEVENTH:  Notwithstanding any other provision of this Certificate
         of Incorporation, any amendment of this Certificate of
         Incorporation, including, without limitation, the amendment of this
         Article ELEVENTH, the effect of which would be to alter, amend,
         supplement or repeal the Bylaws of the Corporation shall not be made
         except by the same affirmative vote of the shareholders as is
         required to make, alter, amend, supplement or repeal the Bylaws
         pursuant to Section 22 of the Bylaws."

SECOND:  That thereafter, at the 1985 Annual Meeting of the Shareholders of
said corporation duly called and held upon notice in accordance with Section
222 of the General Corporation Law of the State of Delaware, the necessary
number of shares as required by statute were voted in favor of the
amendments.

THIRD:  That said amendments were duly adopted in accordance with the
provisions of Section 242 of the General Corporation Law of the State of
Delaware.

FOURTH:  That the capital of said corporation shall not be reduced under or
by reason of said amendment.

IN WITNESS WHEREOF, the Interface Systems, Inc. has caused this certificate
to be signed by Carl L. Bixby, its President, and George W. Perrett, its
Secretary, this 25th day of April, 1985.


                                  By: /S/ Carl L. Bixby
                                      ----------------------------
                                      Carl L. Bixby, President


                             ATTEST: /S/ George W. Perrett
                                     -----------------------------
                                     George W. Perrett


                           Certificate of Amendment
                                      of
                         Certificate of Incorporation

INTERFACE SYSTEMS, INC., a corporation organized and existing under and by
virtue of the General Corporation Law of the State of Delaware,

DOES HEREBY CERTIFY:

FIRST:  That at a meeting of the Board of Directors of Interface Systems,
Inc. a resolution was duly adopted setting forth an amendment of the
Certificate of Incorporation of said corporation, declaring said amendment
to be advisable and calling a meeting of the stockholders of said
corporation for consideration thereof.  The resolution setting forth the
proposed amendment is as follows:

         RESOLVED, That the Certificate of Incorporation of this corporation
         be amended by adding Article TWELFTH so that said Article shall be
         and read in its entirety as follows:

         "TWELFTH:  A director of the Corporation shall not be personally
         liable to the Corporation or its stockholders for monetary damages
         for breach of fiduciary duty as a director, except for liability (i)
         for any breach of the director's duty of loyalty to the Corporation
         or its stockholders, (ii) for acts or omissions not in good faith or
         which involve intentional misconduct or a knowing violation of law,
         (iii) under Section 174 of the General Corporation Law of the State
         of Delaware, as the same exists or hereafter may be amended, or (iv)
         for any transaction from which the director derived an improper
         personal benefit.  If the General Corporation Law of the State of
         Delaware hereafter is amended to authorize the further elimination
         or limitation of the liability of directors, then the liability of a
         director of the Corporation, in addition to the limitation on
         personal liability provided herein, shall be limited to the fullest
         extent permitted by the amended Delaware General Corporation Law of
         the State of Delaware.  Any repeal or modification of this Article
         TWELFTH by the stockholders of the Corporation shall be prospective
         only, and shall not adversely affect any limitation on the personal
         liability of a director of the Corporation existing at the time of
         such repeal or modification."

         SECOND:  That thereafter, at the 1987 Annual Meeting of the
         Stockholders of said corporation duly called and held upon notice in
         accordance with Section 222 of the General Corporation Law of the
         State of Delaware, the necessary number of shares as required by
         statute were voted in favor of the amendment.

         THIRD:  That said amendment was duly adopted in accordance with the
         provisions of Section 242 of the General Corporation Law of the
         State of Delaware.

         FOURTH:  That the capital of said corporation shall not be reduced
         under or by reason of said amendment.

         IN WITNESS WHEREOF, said Interface Systems, Inc. has caused this
         certificate to be signed by David O. Schupp, its Vice President, and
         George W. Perrett, its Secretary, this 12th day of May, 1987.


                                  BY: /S/ David O. Schupp
                                      -------------------------------
                                      David O. Schupp, Vice President


                             ATTEST: /S/ George W. Perrett
                                     --------------------------------
                                     George W. Perrett, Secretary





                           Certificate of Amendment
                                      of
                         Certificate of Incorporation
                                      of
                            Interface Systems, Inc.


         Interface Systems, Inc., a corporation organized and existing under
and by virtue of the General Corporation Law of the State of Delaware,

DOES HEREBY CERTIFY:

         FIRST:  That at a meeting of the Board of Directors of Interface
Systems, Inc., resolutions were duly adopted setting forth a proposed
amendment of the Certificate of Incorporation of said corporation, declaring
said amendment to be advisable and calling a meeting of the shareholders of
said corporation for consideration thereof.  The resolution setting forth
the proposed amendment is as follows:

         RESOLVED, THAT The Certificate of Incorporation shall be amended by
         changing the first paragraph of Article FOURTH thereof, so that, as
         amended, the first paragraph shall read as follows:

         "FOURTH:  The total number of shares of stock, which the Corporation
         shall have authority to issue is Twenty Million (20,000,000) shares
         of Common Stock, par value $.10 per share".

         SECOND.  That thereafter, at the 1996 Annual Meeting of the
Stockholders of said corporation duly called and held upon notice in
accordance with Section 222 of the General Corporation Law of Delaware, the
necessary number of shares as required by statute were voted in favor of the
amendment.

         THIRD.  That said amendment was duly adopted in accordance with
Section 242 of the General Corporation Law of the Sate of Delaware.

         FOURTH.  That the capital of said corporation shall not be reduced
by reason of said amendment.


         IN WITNESS WHEREOF, Interface Systems, Inc. has caused this
certificate to be signed by Carl L. Bixby, its President, and George W.
Perrett, its Secretary, on the      day of May, 1996.


                                          INTERFACE SYSTEMS, INC. 


                                          By: /S/ Carl L. Bixby
                                              --------------------------
                                              Carl L. Bixby
                                              President



                                      Attest: /S/ George W. Perrett
                                              --------------------------
                                              George W. Perrett
                                              Secretary