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                                                                    EXHIBIT 4.13

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                              COMMON STOCK WARRANT

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THE WARRANT REPRESENTED BY THIS CERTIFICATE AND THE UNDERLYING SHARES OF COMMON
STOCK OF OBJECTIVE COMMUNICATIONS, INC. HAVE NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR UNDER THE
SECURITIES LAWS OF ANY STATE. SUCH SECURITIES MAY NOT BE SOLD OR TRANSFERRED
UNLESS THE REGISTRATION PROVISIONS OF SUCH ACT AND LAWS HAVE BEEN COMPLIED WITH
OR UNLESS THE AVAILABILITY OF AN EXEMPTION FROM SUCH REGISTRATION PROVISIONS IS
CONFIRMED TO THE SATISFACTION OF OBJECTIVE COMMUNICATIONS, INC.

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                         OBJECTIVE COMMUNICATIONS, INC.
                              COMMON STOCK WARRANT

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         This is to certify that, for value received, Shaw Pittman Potts &
Trowbridge ("Shaw Pittman") or any subsequent permitted transferee of the
Warrant (together with Shaw Pittman, a "Holder"), is entitled to purchase, on or
before the time specified below and upon and subject to the terms and conditions
hereinafter set forth, forty thousand (40,000) shares of the common stock, par
value $.01 per share (the "Common Stock"), of Objective Communications, Inc., a
Delaware corporation (the "Company"), at a purchase price of $2.656 per share
(the "Purchase Price"), upon presentation of this Warrant and payment of the
Purchase Price, by cash, certified check or wire transfer made payable to or
directed to the account of the Company.

         1. This Warrant may be exercised in whole or in part at any time, or
from time to time, from the date of issuance until its termination date (the
"Termination Date"), which shall be the earlier of: (1) the date that is five
years from the date of issuance; or (2) the occurrence of a Triggering Event (as
hereinafter defined), by presentation to the Company of a Subscription in the
form attached hereto as Exhibit A and incorporated herein by reference. For
purposes of this Warrant, a "Triggering Event" shall mean (i) the merger of the
Company with another entity if the Company is not the surviving entity in such
merger; or (ii) the sale of all or substantially all of the assets of the
Company. The Company shall give each Holder not less than 20 days notice of a
Triggering Event; provided, however, that prior to giving any notice pursuant to
this Warrant, the Holder acknowledges and agrees that the Company may require
the Holder to enter into a confidentiality agreement with respect to any
confidential or proprietary information that may be disclosed to it in
connection with or relating to the Triggering Event and that, if the Holder
fails to enter into such confidentiality agreement, then the Company shall be
relieved of its obligation to give the notice contemplated by this Warrant with
respect to such Triggering Event without breach of this Warrant. This Warrant
shall be null and void after the Termination Date.


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         2. The Holder hereby represents and warrants to the Company, as of the
date of this Warrant and on any subsequent date on which this Warrant is
exercised, in whole or in part, as follows:

         (a) The Holder is an "accredited investor" (as defined in Rule 501 of
         Regulation D promulgated under the Securities Act) and has such
         experience in business and financial matters that it is capable of
         evaluating the merits and risks of an investment in the Warrants and
         the shares of Common Stock of the Company that may be purchased upon
         exercise of this Warrant (the "Warrant Shares"). The Holder is
         purchasing this Warrant and the Warrant Shares for its own account and
         not with a view to distribution and the Holder has no present intention
         or arrangement to sell the Warrant or the Warrant Shares, as the case
         may be, to or through any person or entity. The Holder understands that
         this Warrant and the Warrant Shares, as applicable, must be held
         indefinitely unless such securities are subsequently registered under
         the Securities Act, or an exemption therefrom is available. The Holder
         is aware of the provisions of Regulation D and Rule 144 promulgated
         under the Securities Act.

         (b) The Holder understands and acknowledges that neither this Warrant
         or the Warrant Shares have been registered under the Securities Act,
         that this Warrant and the Warrant Shares, as applicable, are being
         offered and sold to it in reliance on the exemption provided by Section
         4(2) of the Securities Act and Regulation D promulgated thereunder and
         that the Company is relying on the truth and accuracy of the
         representations, warranties, agreements, acknowledgements and
         understandings of the Subscriber set forth in this Warrant in order to
         determine the availability of such provisions. The Holder acknowledges
         that it has been informed by the Company of, or is otherwise familiar
         with, the nature of the limitations imposed by the Securities Act and
         the rules and regulations thereunder relating to the transfer of
         securities.

     3. No Holder may sell or otherwise transfer this Warrant or any Warrant
Shares unless such securities are subsequently registered under the Securities
Act and applicable state securities laws, or an exemption therefrom is
available. Any attempt to transfer this Warrant, any unregistered Warrant
Shares, or any interest in either this Warrant or the Warrant Shares, or to
subject any of the foregoing to execution, attachment or similar process,
contrary to the foregoing provisions shall be void and shall cause this Warrant
to terminate immediately and automatically without any action by the Company.

     4. In case the Company shall at any time after the date this Warrant is
first issued (i) declare a dividend on the outstanding Common Stock payable in
shares of its Common Stock, (ii) subdivide the outstanding Common Stock, or
(iii) combine the outstanding Common Stock into a smaller number of shares,
then, in each case, the Purchase Price per share and the number of Warrant
Shares issuable upon exercise of this Warrant, in effect at the time of the
record date for such dividend or the effective date of such subdivision, or
combination, shall be proportionately adjusted so that the Holder after such
time shall be entitled to receive the aggregate number and kind of shares for
such consideration which, if such Warrant had been exercised immediately prior
to such time at the then-current Purchase Price per share, it would have owned
upon such exercise and been entitled to receive by virtue of such dividend,
subdivision, or combination. Such adjustment shall be made successively whenever
any event listed above shall occur.


Shaw Pittman Potts & Trowbridge Warrant             - 2 -      January 22, 1999

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     5. The Company shall not be required to issue fractions of shares of Common
Stock upon exercise of this Warrant. If any fraction of a share would be
issuable on the exercise of this Warrant, then, upon exercise of this Warrant,
the fraction shall be rounded up or down to the nearest whole number of shares
and the Company shall issue to the Holder such whole number of shares to which
the fraction is rounded.

     6. This Warrant shall not entitle Holder to any of the rights of a
stockholder of the Company. In the absence of affirmative action by Holder to
purchase shares of the Company's Common Stock pursuant to this Warrant, no
provision hereof shall give rise to any liability of Holder for the Purchase
Price or as a stockholder of the Company, whether such liability is asserted by
the Company or by creditors of the Company. Upon exercise of this Warrant,
Holder shall have all of the rights and obligations of holders of the Company's
Common Stock.

     7. This Warrant shall be governed by, and construed and enforced in
accordance with, the laws of the State of New Hampshire, without reference to
conflict of laws principles. The Holder hereby consents to the personal
jurisdiction of the federal and state courts of the State of New Hampshire,
which will be the exclusive forum for all disputes arising under or in
connection with this Warrant. The provisions of this Warrant may be modified,
waived, discharged or terminated only by an instrument in writing executed by
the party against which enforcement of the same is sought.

Date:  January 22, 1999

ATTEST:                                    OBJECTIVE COMMUNICATIONS, INC.
                                           A DELAWARE CORPORATION

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Robert H. Emery                            James F. Bunker
Secretary                                  President and Chief Executive Officer

[Corporate Seal]



Shaw Pittman Potts & Trowbridge Warrant             - 3 -      January 22, 1999
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                                  EXHIBIT A TO
                         OBJECTIVE COMMUNICATIONS, INC.
                              COMMON STOCK WARRANT

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                              FORM OF SUBSCRIPTION
                  (TO BE EXECUTED ONLY ON EXERCISE OF WARRANT)

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Objective Communications, Inc.
50 International Drive
Portsmouth, New Hampshire 03801

         The undersigned, the registered holder of the enclosed Warrant, hereby
irrevocably elects to exercise such Warrant to purchase thereunder
___________________________ (_______) shares of the common stock, par value $.01
per share, of Objective Communications, Inc. and herewith makes payment of

_________________________________________________________________($____________)
therefore, and requests that the certificate(s) for such shares be issued to
______________ ___________________________________________________________, and
be delivered to ___________________________________________________________,
whose address is __________________________________________________________. The
undersigned holder hereby reaffirms the truth and accuracy of the
representations and warranties of the holder set forth in the Warrant.

         If this subscription represents only a portion of the shares eligible
to be purchased under the Warrant, the undersigned requests that a new Warrant
for the remaining shares be issued to the undersigned.

Signed:  
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         (Signature must conform in all respects to the name
         of the registered holder as specified on the face of
         the Warrant.)

Address: 
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Dated:   
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Shaw Pittman Potts & Trowbridge Warrant             - 4 -      January 22, 1999