EXHIBIT T3A-25


                          CERTIFICATE OF INCORPORATION

                                       OF

                   PAGING NETWORK OF NORTHERN CALIFORNIA, INC.

      The undersigned, in order to form a corporation under and pursuant to the
provisions of the General Corporation Law of the State of Delaware, does hereby
certify as follows:

      FIRST: The name of the corporation is: Paging Network of Northern
California, Inc.

      SECOND: The registered office of the corporation in the State of Delaware
is located at 1209 Orange Street, Wilmington, New Castle County, Delaware 19801.
The name of its registered agent at such address is The Corporation Trust
Company.

      THIRD: The nature of the business to be conducted or promoted and the
purposes of the corporation are to engage in any lawful act or activity for
which corporations may be organized under the General Corporation Law of
Delaware.

      FOURTH: The total number of shares of stock which the corporation shall
have the authority to issue is 3,000 shares of Common Stock, $.01 par value per
share.

      FIFTH: The name and mailing address of the incorporator is as follows:



            NAME              MAILING ADDRESS
            ----              ---------------
                           
            Jane E.  Pike     Bingham, Dana & Gould
                              150 Federal Street
                              Boston, MA 02110


      SIXTH: The following provisions are inserted for the management of the
business and for the conduct of the affairs of the corporation, and for
creating, defining, limiting and regulating the powers of the corporation, the
directors and the stockholders.

            (a) Directors need not be stockholders of the corporation.

            (b) Subject to any limitation contained in the by-laws, the board of
      directors may make by-laws, and from time to time may alter, amend or
      repeal any by-laws, but any by-laws made by the board of directors may be
      altered, amended or repealed by the stockholders at any meeting of
      stockholders by the affirmative vote of the holders of a majority of the
      stock present and voting at such meeting, provided notice that an
      amendment is to be considered and acted upon is inserted in the notice or
      waiver of notice of such meeting.

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            (c) The board of directors shall have power from time to time to fix
      and determine and to vary the amount of the working capital of the
      corporation, to direct and determine the use and disposition thereof, to
      set apart out of any funds of the corporation available for dividends a
      reserve or reserves for any proper purposes and to abolish any such
      reserve in the manner in which it was created.

            (d) The board of directors may from time to time determine whether
      and to what extent and at which times and places and under what conditions
      and regulations the accounts and books of the corporation, or any of them,
      shall be open to the inspection of the stockholders, and no stockholder
      shall have any right to inspect any account, book or document of the
      corporation except as conferred by statute or as authorized by the board
      of directors.

            (e) No contract or other transaction between the corporation and one
      or more of its directors or officers, or between the corporation and any
      other corporation, partnership, association or other organization in which
      one or more of its directors or officers are directors or officers, or
      have a financial or other interest, shall be void or voidable solely for
      this reason, or solely because the director or officer is present at or
      participates in the meeting of the board or committee thereof which
      authorized the contract or other transaction, or solely because his or
      their votes are counted for such purpose, provided that the material facts
      as to such relationship or interest and as to the contract or other
      transaction are disclosed or are known (1) to the board of directors or
      the committee, and the board or committee in good faith authorizes the
      contract or other transaction by the affirmative vote of a majority of the
      disinterested directors, even though the disinterested directors be less
      than a quorum, or (2) to the stockholders entitled to vote thereon, and
      the contract or other transaction is specifically approved in good faith
      by vote of the stockholders.

            (f) Any contract, act or transaction of the corporation or of the
      directors may be ratified by a vote of a majority of the shares having
      voting power at any meeting of stockholders, or at any special meeting
      called for such purpose, and such ratification shall, so far as permitted
      by law and by this certificate of incorporation, be as valid and as
      binding as though ratified by every stockholder of the corporation.

            (g) Any vote or votes authorizing liquidation of the corporation or
      proceedings for its dissolution may provide, subject to (i) any agreements
      among and between stockholders, (ii) the rights of creditors and (iii)
      rights expressly provided for particular classes or series of stocks, for
      the distribution pro rata among the stockholders of the corporation of the
      assets of the corporation, wholly or in part in kind, whether such assets
      be in cash or other property, and may authorize the board of directors of
      the corporation to determine the value of the different assets of the

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      corporation for the purpose of such liquidation and may divide or
      authorize the board of directors of the corporation to divide such assets
      or any part thereof among the stockholders of the corporation in such
      manner that every stockholder will receive a proportionate amount in value
      (determined as aforesaid) of cash or property of the corporation upon such
      liquidation or dissolution even though each stockholder may not receive a
      strictly proportionate part of each such asset.

            (h) Elections of directors need not be by ballot.

            (i) The corporation shall, to the maximum extent permitted from time
      to time under the law of the State of Delaware, indemnify and upon request
      shall advance expenses to any person who is or was a party or is
      threatened to be made a party to any threatened, pending or completed
      action, suit, proceeding or claim, whether civil, criminal, administrative
      or investigative, by reason of the fact that he is or was or has agreed to
      be a director or officer of this corporation or while a director or
      officer is or was serving at the request of the corporation as a director,
      officer, partner, trustee, employee or agent of any corporation,
      partnership, joint venture, trust or other enterprise, including service
      with respect to employee benefit plans, against expenses (including
      attorney's fees and expenses), judgments, fines, penalties and amounts
      paid in settlement or incurred in connection with the investigation,
      preparation to defend or defense of such action, suit, proceeding, claim
      or counterclaim initiated by or on behalf of such person. Such
      indemnification shall not be exclusive of other indemnification rights
      arising under any by-law, agreement, vote of directors or stockholders or
      otherwise and shall inure to the benefit of the heirs and legal
      representatives of such person. Any repeal or modification of the
      foregoing provisions of this Section (i) of Article SIXTH shall not
      adversely affect any right or protection of a director or officer of the
      corporation existing at the time of such repeal or modification.

      SEVENTH: No holder of stock of the corporation shall be entitled as of
right to purchase or subscribe for any part of any unissued stock of the
corporation or any additional stock to be issued by reason of any increase of
the authorized capital stock of the corporation, or any bonds, certificates of
indebtedness, debentures or other securities convertible into stock or such
additional authorized issue of new stock, but rather such stock, bonds,
certificates of indebtedness, debentures and other securities may be issued and
disposed of pursuant to resolution of the board of directors to such persons,
firms, corporations or associations, and upon such terms as may be deemed
advisable by the board of directors in the exercise of their discretion.

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      EIGHTH: Meetings of stockholders may be held without the State of
Delaware, if the by-laws so provide. The books of the corporation may be kept
(subject to the provisions of the Delaware General Corporation Law) outside of
the State of Delaware at such place or places as may be from, time to time
designated by the board of directors.

      NINTH: The corporation reserves the right to amend, alter, change or
repeal any provisions contained in this Certificate of Incorporation in the
manner now or hereafter prescribed by statute, and all rights conferred upon
stockholders herein are granted subject to this reservation.

      THE UNDERSIGNED, hereby declaring and certifying that the facts stated in
this Certificate of Incorporation are true, hereunto sets her hand and seal this
14th day of July, 1994.

                                        /s/ Jane E. Pike
                                        ------------------------------
                                        Jane E. Pike, Incorporator