<PAGE>
 
                                 CHATCOM, INC. 


                                                                    EXHIBIT 10.2
                                                                    ------------

    Void after 5:00 p.m. Pacific Standard Time, on December 13, 2001 
Warrant to Purchase One Hundred Thousand (100,000) Shares of Common Stock

                       WARRANT TO PURCHASE COMMON STOCK

                                      OF

                                 CHATCOM, INC.
                           a California corporation

    This is to certify that, for value received, Strategic Growth International,
Inc. ("Holder"), is entitled to purchase, subject to the provisions of this
Warrant, from ChatCom, Inc., a California corporation ("Company"), one hundred
thousand (100,000) fully paid, validly issued and nonassessable shares of common
stock, no par value, of the Company ("Common Stock"), at a price of $3.125 per
share at any time or from time to time during the period from May1, 1997, to
December 13, 2001.

    The number of shares of Common Stock to be received upon the exercise of
this Warrant and the price to be paid for each share of Common Stock may be
adjusted from time to time as hereinafter set forth. The shares of Common Stock
deliverable upon such exercise, and as adjusted from time to time, are
hereinafter sometimes referred to as "Warrant Shares" and the exercise price of
a share of Common Stock in effect at any time and as adjusted from time to time
is hereinafter sometimes referred to as the "Exercise Price".

    1.  Exercise of Warrant. This Warrant may be exercised in whole or in part
        -------------------
at any time from time to time on or after May 1, 1997, and until December 13,
2001; provided however, that if either such day is a day on which banking
institutions in the State of California are authorized by law to close, then on
the next succeeding day which shall not be such a day. This Warrant may be
exercised by presentation and surrender hereof to the Company at its principal
office, with the Purchase Form annexed hereto duly executed, with signature
guaranteed, and accompanied by payment of the Exercise Price for the number of
Warrant Shares specified in such form. As soon as practicable after each
exercise of the Warrants, but not later than twenty (20) days from the date of
such exercise, the Company shall issue and deliver to the Holder a certificate
or certificates for the Warrant Shares issuable upon such exercise, registered
in the name of the Holder or its designee.

    If this Warrant should be exercised in part only, the Company shall, upon
surrender of this Warrant for cancellation, execute and deliver a new Warrant
evidencing the rights of the Holder hereof to purchase the balance of the
Warrant Shares purchasable hereunder. Upon receipt by the Company of this
Warrant at its office, in proper form for exercise, the Holder shall be deemed
to be the holder of 
<PAGE>
 
                                 CHATCOM, INC.


record of the shares of Common Stock issuable upon such exercise,
notwithstanding that the stock transfer books of the Company shall then be
closed or that certificates representing such shares of Common Stock shall not
then by physically delivered to the Holder.

    2.  Reservation of Shares.  The Company shall at all time reserve for
        --------------------- 
issuance and/or delivery upon exercise of this Warrant such number of shares of
its Common Stock as shall be required for issuance and delivery upon exercise of
the Warrants.

    3.  Fractional Shares.  No fractional shares or script representing
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fractional shares shall be issued upon the exercise of this Warrant. With
respect to any fraction of a share called for upon any exercise hereof, the
Company shall pay to the Holder an amount in cash equal to such fraction
multiplied by the current market value of a share, determined as follows:

        3.1.  If the Common Stock is listed on a National Securities Exchange or
admitted to unlisted trading privileges on such exchange or listed for trading
on the NASDAQ system, the current market value shall be the last reported sale
price of the Common Stock on such exchange or system on the last business day
prior to the date of exercise of the Warrant or if no such sale is made on such
day, the average closing bid and asked prices for such day on such exchange or
system; or

        3.2.  If the Common Stock is not so listed or admitted to unlisted
trading privileges, the current market value shall be the mean of the last
reported bid and asked prices reported by the National Quotation Bureau, Inc.,
on the last business day prior to the date of the exercise of this Warrant; or

        3.3.  If the Common Stock is not so listed or admitted to unlisted
trading privileges and did and asked prices are not so reported, the currant
market value shall be an amount, not less than book value thereof as at the end
of the most recent fiscal year of the Company ending prior to the date of the
exercise of the Warrant, determined in such reasonable manner as may be
prescribed by the Board of Directors of the Company.

    4.  Loss of Warrant. Upon receipt by the Company of evidence satisfactory to
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it of the loss, theft, destruction or mutilation of this Warrant, and (in the
case of loss, theft or destruction) of reasonably satisfactory indemnification,
and upon surrender and cancellation of this Warrant, if mutilated, the Company
shall execute and deliver a new Warrant of like tenor and date.

    5.  Rights of the Holder.  The Holder shall not, by virtue hereof, be
        --------------------
entitled to any rights of a shareholder in the Company, either at law or equity,
and the rights of the Holder are limited to those expressed in the Warrant and
are not enforceable against the Company except to the extent set forth herein.
<PAGE>
 
                                 CHATCOM, INC.


    6.  Anti-Dilution Provisions.  The Exercise Price in effect at any time and
        ------------------------
the number and kind of securities purchasable upon the exercise of the Warrants
shall be subject to adjustment from time to time upon the happening of certain
events, as follows:

        6.1.  In case the Company shall (i) declare a dividend or make a
distribution on its outstanding shares of Common Stock in shares of Common
Stock; (ii) subdivide or reclassify its outstanding shares of Common Stock into
a greater number of shares; or (iii) combine or reclassify its outstanding
shares of Common Stock into a smaller number of shares, the Exercise Price in
effect at the time of the record date for such dividend or distribution or of
the effective date of such subdivision, combination or reclassification shall be
proportionately adjusted so that the Holder of this Warrant exercised after such
date shall be entitled to receive the aggregate number and kind of shares which,
if this Warrant had been exercised by such Holder immediately prior to such
date, he would have owned upon such exercise and been entitled to receive upon
such dividend, subdivision, combination or reclassification.

        6.2.  In case the Company shall hereafter distribute to the holders of
its Common Stock evidences of its indebtedness or assets (excluding cash
dividends or distributions and dividends or distributions referred to in
Subsection 6.1 above) or subscription rights or warrants, then in each such case
the Exercise Price in effect thereafter shall be determined by multiplying the
Exercise Price in effect immediately prior thereto by a fraction, the numerator
of which shall be the total number of shares of Common Stock outstanding
multiplied by the current market price per share of Common Stock (as defined in
Subsection 6.7 below), less the fair market value (as determined by the
Company's Board of Directors) of said assets or evidences of indebtedness so
distributed or of such rights or warrants, and the denominator of which shall be
the total number of shares of Common Stock outstanding multiplied by such
current market price per share of Common Stock. Such adjustment shall be made
whenever any such distribution is made and shall become effective immediately
after the record date for the determination of shareholders entitled to receive
such distribution.

        6.3  Whenever the Exercise Price payable upon exercise of each Warrant
is adjusted pursuant to Subsections 6.1 and 6.2 above, the number of shares
purchasable upon exercise of this Warrant shall simultaneously be adjusted by
multiplying the number of shares initially issuable upon exercise of this
Warrant by the Exercise Price in effect on the date hereof and dividing the
product so obtained by the Exercise Price, as adjusted.

        6.4. For the purposes of any computation under Subsection 6.2 above, the
current market price per share of Common Stock at any date shall be deemed to be
the average of the daily closing prices for ten (10) consecutive business days
before 
<PAGE>
 
                                 CHATCOM, INC.


such date. The closing price for each day shall be the last sale price regular
way or, in case no such reported sale takes place on such day, the average of
the last reported bid and asked prices regular way, in either case on the
principal national securities exchange on which the Common Stock is admitted to
trading or listed, or if not listed or admitted to trading on such exchange, the
average of the highest reported bid and lowest reported asked prices as reported
by NASDAQ, or other similar organization, if NASDAQ is no longer reporting such
information, or if not so available, the fair market price as determined by the
Board of Directors.

        6.8  No adjustment in the Exercise Price shall be required unless such
adjustment would require an increase or decrease of at least five cents ($0.05)
in such price. All calculations under this Section 6 shall be made to the
nearest cent or to the nearest one-hundredth of a share, as the case may be.

    7.  Reclassification, Reorganization or Merger.  In case of any
        ------------------------------------------
reclassification, capital reorganization or other change of outstanding shares
of Common Stock of the Company, or in case of any consolidation or merger of the
Company with or into another corporation, or in case of any sale, lease or
conveyance to another corporation of the property of the Company as an entirety,
the Company shall, as a condition precedent to such transaction, cause effective
provisions to be made so that the Holder shall have the right thereafter by
exercising this Warrant at anytime prior to the expiration of the Warrant, to
purchase the kind and amount of shares of stock and other securities and
property receivable upon such reclassification, capital reorganization and other
change, consolidation, merger, sale or conveyance by a holder of the number of
shares of Common Stock which might have been purchased upon the exercise of this
Warrant, immediately prior to such reclassification, change, consolidation,
merger, sale or conveyance.


Dated:  December 13, 1996               CHATCOM, INC.,
                                        a California corporation



                                     By:
                                        -------------------------------------
                                        James B. Mariner
                                        President and Chief Executive Officer
<PAGE>
 
                                 CHATCOM, INC.


                                 PURCHASE FORM
                                 -------------

                                          Dated:  _______________________, 19___

    The undersigned hereby irrevocably elects to exercise the within Warrant to
the extent of purchasing _________________ shares of Common Stock and hereby
makes payment of __________________ in payment of the actual exercise price
hereof.


                                              -------------------------------  
                                              Name Printed:
                                                           ------------------
                                              Warrant holder



                    INSTRUCTIONS FOR REGISTRATION OF STOCK
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