<PAGE>   1
                                                                   EXHIBIT 4.2


           THIS WARRANT AND THE SHARES OF COMMON STOCK ISSUABLE UPON EXERCISE
           HEREOF HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
           AMENDED (THE "ACT"), OR ANY STATE SECURITIES OR BLUE SKY LAWS AND MAY
           NOT BE OFFERED, SOLD, TRANSFERRED, HYPOTHECATED OR OTHERWISE ASSIGNED
           EXCEPT (1) PURSUANT TO A REGISTRATION STATEMENT WITH RESPECT TO SUCH
           SECURITIES WHICH IS EFFECTIVE UNDER THE ACT OR (2) PURSUANT TO AN
           AVAILABLE EXEMPTION FROM REGISTRATION UNDER THE ACT RELATING TO THE
           DISPOSITION OF SECURITIES AND (3) IN ACCORDANCE WITH APPLICABLE STATE
           SECURITIES AND BLUE SKY LAWS.


                                     WARRANT


               WARRANT TO PURCHASE ______________________________________
                 (___________________) SHARES OF COMMON STOCK


                                      OF


                      SONUS COMMUNICATION HOLDINGS, INC.


                      Date of Issuance: July ____, 2000


                                No.__________

THIS CERTIFIES that, for value received, ________________________________, or
its assigns (in either case, the "Holder") is entitled to purchase, subject to
the provisions of this Warrant, from SONUS COMMUNICATION HOLDINGS, INC., a
Delaware corporation (the "Company"), at the price per share set forth in
Section 8 hereof, the number of shares of the Company's common stock, $.0001 par
value per share (the "Common Stock"), set forth in Section 7 hereof. This
Warrant is referred to herein as the "Warrant" and the shares of Common Stock
issuable pursuant to the terms hereof are sometimes referred to herein as
"Warrant Shares". Capitalized terms used but not defined herein shall have the
respective meanings accorded such terms in the Confidential Private Placement
Memorandum dated July 5, 2000.

      Section 1. Exercise of Warrant. To exercise this Warrant in whole or in
part, the Holder shall deliver to the Company at its principal office, (a) a
written notice, in substantially the form of the exercise notice attached
hereto (the "Exercise Notice"), of the Holder's election to exercise this
Warrant, which notice shall specify the number of shares of Common Stock to be
purchased, (b) a check in the amount of the aggregate exercise price for the
Warrant Shares being purchased, and (c) this Warrant. The Company shall as
promptly as practicable, and in any event within twenty (20) days after
delivery to the Company of (i) the Exercise Notice, (ii) the check mentioned
above, and (iii) this Warrant, execute and deliver or cause to be executed and
delivered, in accordance with such notice, a certificate or certificates
representing the aggregate number of shares of Common Stock specified in such
notice, provided the Warrants specified in such notice have


                                                                              32
<PAGE>   2

vested on or prior to the date such notice is delivered. If the Holder elects to
purchase, at any time, less than the number of shares of Common Stock then
purchasable under the terms of this Warrant, the Company shall issue to the
Holder a new Warrant exercisable into the number of remaining shares of Common
Stock purchasable under this Warrant. Each certificate representing Warrant
Shares shall bear the legend or legends required by applicable securities laws
as well as such other legend(s) the Company requires to be included on
certificates for its Common Stock. The Company shall pay all expenses, taxes and
other charges payable in connection with the preparation, issuance and delivery
of such stock certificates except that, in case such stock certificates shall be
registered in a name or names other than the name of the Holder, funds
sufficient to pay all stock transfer taxes that are payable upon the issuance of
such stock certificate or certificates shall be paid by the Holder at the time
of delivering the Exercise Notice. All shares of Common Stock issued upon the
exercise of this Warrant shall be validly issued, fully paid, and nonassessable.
This Warrant may be exercised on multiple occasions in amounts not less than 15%
of the original amount issued before the expiration of its term as described in
this Section 1. This Warrant will expire on July 24, 2005 (the "Expiration
Date").

       Section 2. Reservation of Shares. The Company hereby covenants that at
all times during the term of this Warrant there shall be reserved for issuance
such number of shares of its Common Stock as shall be required to be issued upon
exercise of this Warrant.

       Section 3. Fractional Shares. This Warrant may be exercised only for a
whole number of shares of Common Stock, and no fractional shares or scrip
representing fractional shares shall be issuable upon the exercise of this
Warrant.

       Section 4. Transfer of Warrant and Warrant Shares. The Holder may sell,
pledge, hypothecate, or otherwise transfer this Warrant, in whole or in part,
only in accordance with and subject to the terms and conditions set forth in the
Subscription Agreement and then only if such sale, pledge, hypothecation, or
transfer is made in compliance with the Act or pursuant to an available
exemption from registration under the Act relating to the disposition of
securities, and is made in accordance with applicable State securities laws.

       Section 5. Loss of Warrant. Upon receipt by the Company of evidence
satisfactory to it of the loss, theft, or destruction of this Warrant, and of
indemnification satisfactory to it, or upon surrender and cancellation of this
Warrant, if mutilated, the Company will execute and deliver a new Warrant of
like tenor.

       Section 6. Rights of the Holder. No provision of this Warrant shall be
construed as conferring upon the Holder the right to vote, consent, receive
dividends or receive notice other than as expressly provided herein. Prior to
exercise, no provision hereof, in the absence of affirmative action by the
Holder to exercise this Warrant, and no enumeration herein of the rights or
privileges of the Holder, shall give rise to any liability of the Holder for the
purchase price of any Warrant Shares or as a stockholder of the Company, whether
such liability is asserted by the Company or by creditors of the Company.


       Section 7. Number of Warrant Shares. This Warrant shall be exercisable
for up to ________________________________ (_______________) shares of the
Company's Common Stock, as adjusted in accordance with this Agreement.


       Section 8. Exercise Price; Redemption; Adjustment of Warrants.


                                                                              33
<PAGE>   3

       (a) Determination of Exercise Price. The per share purchase price (the
"Exercise Price") for each of the Warrant Shares purchasable under this Warrant
shall be equal to sixty cents ($0.60).

       (b) Redemption of Warrants. In the event (i) a registration statement has
been filed under the Securities Act covering the Warrant Shares and other
securities which the Company is contractually obligated to register, and such
registration statement is declared effective by the Securities and Exchange
Commission, and (ii) the bid price of the Common Stock on the OTC Bulletin Board
or other exchange is $1.00 or higher for twenty consecutive trading days, the
Company shall have the option to deliver a redemption notice (the "Redemption
Notice") to the holder of this Warrant. Upon delivery of the Redemption Notice,
all Warrants which remain outstanding on the 30th day following delivery of the
Redemption Notice shall be automatically redeemed by the Company for $.01 per
Warrant (the "Redemption Price"). All such unexercised Warrants shall be deemed
cancelled upon the Company's delivery of the Redemption Price to the Holder.
Upon receipt of the Redemption Price, Holder agrees to return any documentation
of the unexercised Warrants to the Company.

       (c) Adjustments for Stock Dividends, Distributions and Subdivisions. If
the Company at any time or from time to time after the original issue date shall
declare or pay any dividend or distribution on the Common Stock payable in
Common Stock, or effect a subdivision of the outstanding shares of Common Stock
into a greater number of shares of Common Stock (by reclassification or
otherwise than by payment of a dividend in Common Stock), then the number of
shares of Common Stock into which this Warrant is exercisable shall be increased
to an amount which is equal to the product of (i) the number of shares of Common
Stock for which this Warrant is exercisable immediately prior to the stock
dividend, distribution or subdivision, as the case may be, and (ii) a fraction,
the numerator of which is equal to the number of shares of Common Stock issued
and outstanding after giving effect to such stock dividend, distribution or
subdivision, and the denominator of which is the number of shares of Common
Stock issued and outstanding prior to such stock dividend, distribution or
subdivision. If the outstanding shares of Common Stock shall be divided or
increased because of a stock dividend or distribution, by stock split or
otherwise, into a greater number of shares of Common Stock, the Exercise Price
in effect immediately prior to such dividend, distribution or division shall,
concurrently with the effectiveness of such division, dividend or distribution,
be proportionately decreased.

       (d) Adjustments for Combinations or Consolidation of Common Stock. If the
outstanding shares of Common Stock shall be combined or consolidated, by
reclassification, reverse stock split or otherwise, into a lesser number of
shares of Common Stock, then the number of shares of Common Stock into which
this Warrant is exercisable shall be decreased to an amount which is equal to
the product of (i) the number of shares of Common Stock for which this Warrant
is exercisable immediately prior to combination or consolidation, as the case
may be, and (ii) a fraction, the numerator of which is equal to the number of
shares of Common Stock issued and outstanding after giving effect to such
combination or consolidation, and the denominator of which is the number of
shares of Common Stock issued and outstanding prior to such combination or
consolidation. If the outstanding shares of Common Stock shall be combined or
consolidated, by reclassification, reverse stock split or otherwise, into a
lesser number of shares of Common Stock, the Exercise Price in effect
immediately prior to such combination or consolidation shall, concurrently with
the effectiveness of such combination or consolidation, be proportionately
increased.

       (e) Adjustment for Mergers or Reorganization, etc. In case of any
consolidation or merger of the Company with or into another corporation or the
conveyance of all or substantially all of the assets of the Company to another
corporation, this Warrant shall be exercisable into the number of shares of
stock or other securities or property to which a holder of the number of shares
of Common Stock of the Company deliverable upon exercise of this Warrant would
have been entitled upon such consolidation, merger or conveyance; and, in any
such case, appropriate adjustment (as determined by the Board of Directors of
the Company) shall be made in the application




                                                                              34
<PAGE>   4

of the provisions herein set forth with respect to the rights and interest
thereafter of the holder of this Warrant, to the end that the provisions set
forth herein shall thereafter be applicable, as nearly as reasonable may be, in
relation to any shares of stock or other property thereafter deliverable upon
the exercise of this Warrant.

       (f) No Impairment. The Company will not, through any reorganization,
transfer of assets, consolidation, merger, dissolution, issue or sale of
securities or any other voluntary action, avoid or seek to avoid the observance
or performance of any of the terms to be observed or performed hereunder by the
Company, but will at all times in good faith assist in the carrying out of all
the provisions of this Section 8 and in the taking of all such action as may be
necessary or appropriate in order to protect the exercise rights of the holder
of this Warrant against impairment.

       (g) Issue Taxes. The Company shall pay any and all issue and other taxes
that may be payable in respect of any issue or delivery of shares of Common
Stock on exercise of this Warrant, in whole or in part; provided, however, that
the Company shall not be obligated to pay any transfer taxes resulting from any
transfer requested by any holder in connection with any such exercise.

       (h) Reservation of Stock Issuable Upon Conversion. The Company shall at
all times reserve and keep available out of its authorized but unissued shares
of Common Stock, solely for the purpose of effecting the exercise of this
Warrant, such number of its shares of Common Stock as shall from time to time be
sufficient to effect the exercise of this Warrant; and if at any time the number
of authorized but unissued shares of Common Stock shall not be sufficient to
effect the exercise of this Warrant, the Company will take all appropriate
corporate action as may, in the opinion of its counsel, be necessary to increase
its authorized but unissued shares of Common Stock to such number of shares as
shall be sufficient for such purpose.

       (i) Fractional Shares. No fractional share shall be issued upon the
exercise, in whole or in part, of this Warrant. If any exercise in whole or in
part of this Warrant would result in the issuance of a fraction of a share of
Common Stock, the Company shall, in lieu of issuing any fractional share, pay
the holder otherwise entitled to such fraction a sum in cash equal to the fair
market value of such fraction on the date of exercise (as determined in good
faith by the Board of Directors of the Company).

       Section 9. Piggy-Back Registration Rights.

       (a) Grant of Piggy-Back Rights. In the event that the Company shall
hereafter initiate a registration of any of its common stock, par value $.001
per share (a "Registered Offering"), either for its own account or the account
of any other holder or holders of equity securities or securities convertible
into equity securities of the Company, other than (i) a registration relating
solely to employee benefit plans, (ii) a registration relating solely to a Rule
145 transaction, (iii) a registration in which the only equity security being
registered is capital stock issuable upon conversion of convertible (or exchange
of exchangeable) debt securities which are also being registered, or (iv) an
initial public offering of the Company, the Company will provide you with
written notice thereof within 30 days of the filing date of the first
registration statement filed in connection with the Registered Offering (the
"Company Notice"), and, subject to the other terms and conditions set forth in
this Section, include in such registration (and any related qualification under
blue sky laws or other compliance) and any underwriting involved therein, if
any, the Warrant Shares which the Holder requests to be included therein within
10 days after the date of the Company Notice (collectively, the "Registrable
Securities").

       (b) Underwritten Registered Offering. If the Registered Offering of which
the Company gives notice is for a registered public offering involving an
underwriting, the Company shall so advise you as a part of the Company Notice.
In such event, your rights to registration pursuant to this Section 9 shall be
conditioned upon your participation in such underwriting, and the inclusion of
your Registrable Securities in the underwriting shall be limited to the extent
provided herein. You shall (together with the Company and the other holders
distributing their securities through such underwriting, if any) enter into an
underwriting agreement in customary form with the managing underwriter selected
for such underwriting by the Company. Notwithstanding any other provision of
this Section 9, if the managing underwriter determines that marketing factors
require a limitation of the number of shares to be underwritten, the managing
underwriter may limit the number of your Registrable Securities to be included
in such registration to such number of your Registrable Securities which the
managing underwriter determines can be included in such underwriting without
reducing the number of shares to be sold by the Company pursuant to such
underwriting or by any persons or entities exercising demand registration rights
in connection with such registration. In such event, the Company shall so advise
you and the number of shares (other than shares being registered by the Company)
that may be included in the registration and underwriting shall be allocated
among all the holders of the Company's shares wishing to participate in the
Registered Offering in proportion, as nearly as practicable, to the respective
amounts of shares held by such holders at the time of filing the Registration
Statement. To facilitate the




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<PAGE>   5

allocation of shares in accordance with the above provisions, the Company may
round the number of shares allocated to any holder to the nearest 100 shares. If
you disapprove of the terms of any such underwriting, you may elect to withdraw
therefrom by written notice to the Company and the managing underwriter. Any
securities excluded or withdrawn from such underwriting shall be withdrawn from
such registration, and shall not be transferred in a public distribution prior
to 180 days after the effective date of the registration statement relating
thereto, or such other shorter period of time as the underwriters may require.

       (c) Termination and Withdrawal of Registration. The Company shall have
the right to terminate or withdraw any Registered Offering or other registration
prior to the effectiveness of such registration whether or not you have elected
to include your Registrable Securities in such registration.

       (d) Expenses. All registration expenses incurred in connection with
registrations pursuant to this Section 9 shall be borne by the Company. Unless
otherwise stated, all selling expenses relating to your Registrable Securities
shall be borne by you.

       (e) Notification Requirements. In the case of each registration,
qualification or compliance effected by the Company pursuant to this Agreement,
the Company will keep you advised in writing as to the initiation of each
registration, qualification and compliance and as to the completion thereof. At
its expense the Company will:

           (i)       prepare and file with the Commission a registration
statement with respect to such securities and use reasonable best efforts to
cause such registration statement to become and remain effective for at least
one hundred twenty (120) days or until the distribution described in the
registration statement has been completed, whichever first occurs; and

           (ii)      furnish to you, should you participate in such
registration, and to the underwriters of the securities being registered such
reasonable number of copies of the registration statement, preliminary
prospectus, final prospectus and such other documents you and/or the
underwriters may reasonably request in order to facilitate the public offering
of such securities.

       (f) Underwriting Agreement Governs. In the event the terms of this
Section 9 conflicts with the terms of any underwriting agreement in connection
with any registration hereunder, the terms of such underwriting agreement shall
control.

       (g) Information. If your Registrable Securities are to be included in any
Registered Offering, you shall furnish to the Company such information as the
Company may request in writing and as shall be required in connection with any
registration, qualification or compliance referred to in this Agreement.

       (h) Termination. The rights granted pursuant to this Section 9 shall
terminate at such time as the Company has registered your Registrable Securities
in a Registered Offering or other registration or when you are permitted to sell
all of your Warrant Shares within any ninety day period under Rule 144
promulgated under the Securities Act of 1933.

       Section 10. Certain Distributions. In case the Company shall, at any
time, prior to the Expiration Date set forth in Section 1 hereof, declare any
distribution of its assets to holders of its Common Stock as a partial
liquidation, distribution or by way of return of capital, other than as a
dividend payable out of earnings or any surplus legally available for dividends,
then the Holder shall be entitled, upon the proper exercise of this Warrant in
whole or in part prior to the effecting of such declaration, to receive, in
addition to the shares of Common Stock issuable on such exercise, the amount of
such assets (or at the option of the Company a sum equal to the value thereof at
the time of such distribution to holders of Common Stock as such value is
determined by the Board of Directors of the Company in good faith), which would
have been payable to the Holder had it been a holder of record of such shares of
Common Stock on the record date for the determination of those holders of Common
Stock entitled to such distribution.

       Section 11. Dissolution or Liquidation. In case the Company shall, at any
time prior to the Expiration Date set forth in Section 1 hereof, dissolve,
liquidate or wind up its affairs, the Holder shall be entitled, upon the proper
exercise of this Warrant in whole or in part and prior to any distribution
associated with such dissolution, liquidation, or winding up, to receive on such
exercise, in lieu of the shares of Common Stock to which the Holder would have
been entitled, the same kind and amount of assets as would have been
distributed or paid to the Holder upon any such dissolution, liquidation or
winding up, with respect to such shares of Common Stock



                                                                              36
<PAGE>   6
had the Holder been a holder of record of such share of Common Stock on the
record date for the determination of those holders of Common Stock entitled to
receive any such dissolution, liquidation, or winding up distribution.

       Section 12. Reclassification or Reorganization. In case of any
reclassification, capital reorganization or other change of outstanding shares
of Common Stock of the Company (other than a change in par value, or from par
value to no par value, or from no par value to par value, or as a result of an
issuance of Common Stock by way of dividend or other distribution or of a
subdivision or combination), the Company shall cause effective provision to be
made so that the Holder shall have the right thereafter by exercising this
Warrant, to purchase the kind and amount of shares of stock and other securities
and property receivable upon such reclassification, capital reorganization or
other change, by a holder of the number of shares of Common Stock which might
have been purchased upon exercise of this Warrant immediately prior to such
reclassification or change. Any such provision shall include provision for
adjustments which shall be as nearly equivalent as may be practicable to the
adjustments provided for in this Warrant. The foregoing provisions of this
Section 12 shall similarly apply to successive reclassifications, capital
reorganizations and changes of shares of Common Stock. In the event that in any
such capital reorganization, reclassification, or other change, additional
shares of Common Stock shall be issued in exchange, conversion, substitution or
payment, in whole or in part, for or of a security of the Company other than
Common Stock, any amount of the consideration received upon the issue thereof
being determined by the Board of Directors of the Company shall be final and
binding on the Holder.

       Section 13. Indemnification.

       (a) Indemnification. The Holders agree, if any of Holders' Registrable
Securities are included in the securities as to which such registration,
qualification or compliance is being effected, to indemnify the Company, each of
its directors and officers, each underwriter, if any, of the Company's
securities covered by such a registration statement, each Person who controls
the Company or such underwriter within the meaning of Section 15 of the
Securities Act, and each other such holder, each of its officers and directors
and each Person controlling such holder within the meaning of Section 15 of the
Securities Act, against all claims, losses, damages and liabilities (or actions
in respect thereof) arising out of or based on any untrue statement (or alleged
untrue statement) of a material fact contained in any such registration
statement, prospectus, offering circular or other document, or any omission (or
alleged omission) to state therein a material fact required to be stated therein
or necessary to make the statements therein not misleading, and will reimburse
the Company, such holders, such directors, officers, Persons, underwriters or
control Persons for any legal or any other expenses reasonably incurred, as such
expenses are incurred, in connection with investigating or defending any such
claim, loss, damage, liability or action, in each case to the extent, but only
to the extent, that such untrue statement (or alleged untrue statement) or
omission (or alleged omission) is made in such registration statement,
prospectus, offering circular or other document in reliance upon and in
conformity with written information furnished to the Company by you.
Notwithstanding the foregoing, your liability under this subsection shall be
limited in an amount equal to the initial price of the Registrable Securities
sold by you, unless such liability arises out of or is based on willful
misconduct by you.

       (b) Indemnification Procedure. Each party entitled to indemnification
under this Section (the "Indemnified Party") shall give notice to the party
required to provide indemnification (the "Indemnifying Party") after such
Indemnified Party has actual knowledge of any claim as to which indemnity may be
sought, and shall permit the Indemnifying Party to assume the defense of any
such claim or any litigation resulting therefrom, provided that counsel for the
Indemnifying Party, who shall conduct the defense of such claim or litigation,
shall be approved by the Indemnified Party (whose approval shall not be
unreasonably withheld), and the Indemnified Party may participate in such
defense at such party's expense, and provided further that the failure of any
Indemnified Party to give notice as provided herein shall not relieve the
Indemnifying Party of its obligations under this Agreement, unless the failure
to give such notice is materially prejudicial to an Indemnifying Party's ability
to defend such action, and provided further that the Indemnifying Party shall
not assume the defense for matters as to which there is a conflict of interest
or separate and different defenses. No Indemnifying Party, in the defense of any
such claim or litigation, shall, except with the consent of each Indemnified
Party, consent to entry of any judgment




                                                                              37
<PAGE>   7

or enter into any settlement which does not include as an unconditional term
thereof the giving by the claimant or plaintiff to such Indemnified Party of a
release from all liability in respect to such claim or litigation.

       Section 14. Miscellaneous.

       (a) Successors and Assigns. The terms and conditions of this Agreement
shall inure to the benefit of, and be binding upon, the respective successors
and assigns of the parties, except to the extent otherwise provided herein.
Nothing in this Agreement, express or implied, is intended to confer upon any
party, other than the parties hereto or their respective successors and assigns,
any rights, remedies, obligations or liabilities under or by reason of this
Agreement, except as expressly provided in this Agreement.

       (b) Governing Law. This Agreement shall be governed by and construed in
accordance with the laws of the State of Delaware, without regard to the
principles of conflict of laws thereof.

       (c) Counterparts; Delivery by Facsimile. This Agreement may be executed
in one or more counterparts, each of which shall be deemed an original, but all
of which together shall constitute one and the same instrument. Delivery of this
Agreement may be effected by facsimile.

       (d) Titles and Subtitles. The titles and subtitles used in this Agreement
are used for convenience only and are not to be considered in construing or
interpreting this Agreement.

       (e) Notices. Unless otherwise provided, any notice required or permitted
hereunder shall be given by personal service upon the party to be notified, by
nationwide overnight delivery service or upon deposit with the United States
Post Office, by certified mail, return receipt requested and:

               i.  if to the Company, addressed to SONUS COMMUNICATION HOLDINGS,
INC., 1600 Wilson Blvd., Suite 1008, Arlington, Virginia 22209, Attention: W.
Todd Coffin, with a copy to Cecil E. Martin, III, Esquire, McGuireWoods LLP,
Seven Saint Paul Street, Suite 1000, Baltimore, Maryland 21202-1626, or at such
other address as the Company may designate by notice to each of the Investors in
accordance with the provisions of this Section; and

               ii.  if to the Warrant holder, at the address indicated on the
signature pages hereof, or at such other addresses as such Holder may designate
by notice to the Company in accordance with the provisions of this Section.

       (f) Amendments and Waivers. Any term of this Agreement may be amended and
the observance of any term of this Agreement may be waived (either generally or
in a particular instance and either prospectively or retroactively), only with
the written consent of the Company and a majority in interest of the Holders
receiving Warrants in the Offering.

(g) Entire Agreement. This Agreement and the Subscription Agreement (including
the exhibits and schedules hereto) constitute the entire agreement among the
parties hereto with respect to the subject matter hereof and thereof and
supersede all prior agreements, understandings, negotiations and discussions,
whether oral or written, of the parties hereto.

       IN WITNESS WHEREOF, the undersigned hereby sets is hand and seal this
____ day of July, 2000.

                                SONUS COMMUNICATION HOLDINGS, INC.

                                By:
                                   --------------------------------------------
                                Name: John K. Friedman
                                Title:    President


                                Investor Name:
                                              ---------------------------------
                                Investor Address:
                                                 ------------------------------







                                                                              38
<PAGE>   8



                                 EXERCISE NOTICE



Dated: _____________________

The undersigned hereby irrevocably elects to exercise his, her or its right to
purchase _________ shares of the common stock, $.0001 par value per share (the
"Common Stock"), of SONUS COMMUNICATION HOLDINGS, INC., a Delaware corporation
(the "Company"), such right being pursuant to a Warrant dated
__________________, 2000, and as issued to the undersigned by the Company, and
remits herewith the sum of $______ in payment for same in accordance with the
Exercise Price specified in Section 8 of said Warrant.



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<PAGE>   9


                                 ASSIGNMENT FORM


Dated: _____________________

           For value received ____________________ hereby sells, assigns and
           transfers unto
           Name:
                --------------------------------------------
                 (Please typewrite or print block letters)

           Address:
                    ----------------------------------------

                    ----------------------------------------

    and appoints:
                    ----------------------------------------

                    ----------------------------------------

Attorney to transfer the said Warrant on the books of SONUS COMMUNICATION
HOLDINGS, INC. with full power of substitution in the premises.

                                Signature:
                                           ------------------------------






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