<PAGE>

                                                                   Exhibit 10.15

                                                                       EXHIBIT E

NEITHER THIS WARRANT NOR THE SHARES ISSUABLE UPON EXERCISE HEREOF HAVE BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT")
OR ANY OTHER APPLICABLE STATE SECURITIES LAWS IN RELIANCE UPON AN EXEMPTION FROM
THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT PURSUANT TO REGULATION D AND
SUCH OTHER SECURITIES LAWS. NEITHER THIS WARRANT NOR THE SHARES ISSUABLE UPON
EXERCISE HEREOF MAY BE SOLD, PLEDGED, TRANSFERRED, ENCUMBERED OR OTHERWISE
DISPOSED OF EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE
SECURITIES ACT OR IN A TRANSACTION WHICH IS EXEMPT FROM REGISTRATION UNDER THE
PROVISIONS OF THE SECURITIES ACT AND ANY APPLICABLE STATE LAWS. THIS WARRANT MAY
NOT BE EXERCISED BY OR ON BEHALF OF A UNITED STATES PERSON UNLESS REGISTERED
UNDER THE SECURITIES ACT OR AN EXEMPTION FROM SUCH REGISTRATION IS AVAILABLE, AS
REQUIRED BY REGULATION D.


                            STOCK PURCHASE WARRANT


               To Purchase ___________ Shares of Common Stock of

                                DATA RACE, INC.

          THIS CERTIFIES that, for value received, [PURCHASER] (the "Holder"),
is entitled, upon the terms and subject to the limitations on exercise and the
conditions hereinafter set forth, at any time on or after June __, 2001 (the
"Initial Exercise Date") and on or prior to the close of business on the fourth
anniversary of the Initial Exercise Date (the "Termination Date") but not
thereafter, to subscribe for and purchase from Data Race, Inc., a corporation
incorporated in the State of Texas (the "Company"), up to ___________ shares
(the "Warrant Shares") of Common Stock, $___ par value per share, of the Company
(the "Common Stock"). The purchase price of one share of Common Stock (the
"Exercise Price") under this Warrant shall be $_____. The Exercise Price and the
number of Warrant Shares for which the Warrant is exercisable shall be subject
to adjustment as provided herein. Capitalized terms used and not otherwise
defined herein shall have the meanings set forth in that certain Convertible
Debentures and Warrants Purchase Agreement (the "Purchase Agreement"), dated
June 12, 2001, between the Company and the investors signatory thereto.

                                       1
<PAGE>

          1.   Title to Warrant. Prior to the Termination Date and subject to
               ----------------
compliance with applicable laws, this Warrant and all rights hereunder are
transferable, in whole or in part, at the office or agency of the Company by the
Holder in person or by duly authorized attorney, upon surrender of this Warrant
together with the Assignment Form annexed hereto properly endorsed.

          2.   Authorization of Shares. The Company covenants that all Warrant
               -----------------------
Shares which may be issued upon the exercise of the purchase rights represented
by this Warrant will, upon exercise of the purchase rights represented by this
Warrant, be duly authorized, validly issued, fully paid and nonassessable and
free from all taxes, liens and charges in respect of the issue thereof (other
than taxes in respect of any transfer occurring contemporaneously with such
issue).

          3.   Exercise of Warrant.
               -------------------

                    (a)  Except as provided in Section 4 herein, exercise of the
     purchase rights represented by this Warrant may be made at any time or
     times on or after the Initial Exercise Date and on or before the
     Termination Date by the surrender of this Warrant and the Notice of
     Exercise Form annexed hereto duly executed, at the office of the Company
     (or such other office or agency of the Company as it may designate by
     notice in writing to the registered Holder at the address of such Holder
     appearing on the books of the Company) and upon payment of the Exercise
     Price of the shares thereby purchased by wire transfer or cashier's check
     drawn on a United States bank, or by means of a cashless exercise, the
     Holder shall be entitled to receive a certificate for the number of Warrant
     Shares so purchased. Certificates for shares purchased hereunder shall be
     delivered to the Holder within three (3) Trading Days after the date on
     which this Warrant shall have been exercised as aforesaid. This Warrant
     shall be deemed to have been exercised and such certificate or certificates
     shall be deemed to have been issued, and Holder or any other person so
     designated to be named therein shall be deemed to have become a holder of
     record of such shares for all purposes, as of the date the Warrant has been
     exercised by payment to the Company of the Exercise Price and all taxes
     required to be paid by the Holder, if any, pursuant to Section 5 prior to
     the issuance of such shares, have been paid.

                    (b)  If this Warrant shall have been exercised in part, the
     Company shall, at the time of delivery of the certificate or certificates
     representing Warrant Shares, deliver to Holder a new Warrant evidencing the
     rights of Holder to purchase the unpurchased Warrant Shares called for by
     this Warrant, which new Warrant shall in all other respects be identical
     with this Warrant.

                    (c)  This Warrant shall also be exercisable by means of a
     "cashless exercise" in which the Holder shall be entitled to receive a
     certificate for the number of Warrant Shares equal to the quotient obtained
     by dividing [(A-B) (X)] by (A), where:

                    (A) = the average of the high and low trading prices per
                    share of Common Stock on the Trading Day preceding the date
                    of such election on the

                                       2
<PAGE>

                    Nasdaq Stock Market, or if the Common Stock is not traded on
                    the Nasdaq Stock Market, then the Principal Market in terms
                    of volume;

                    (B) = the Exercise Price of this Warrant; and

                    (X) = the number of Warrant Shares issuable upon exercise of
                    this Warrant in accordance with the terms of this Warrant
                    and the Notice of Exercise.

                    (d)  Notwithstanding anything herein to the contrary, in no
     event shall the Holder be permitted to exercise this Warrant for Warrant
     Shares to the extent that (i) the number of shares of Common Stock owned by
     such Holder (other than Warrant Shares issuable upon exercise of this
     Warrant) plus (ii) the number of Warrant Shares issuable upon exercise of
     this Warrant, would be equal to or exceed 9.9% of the number of shares of
     Common Stock then issued and outstanding, including shares issuable upon
     exercise of this Warrant held by such Holder after application of this
     Section 3(d). As used herein, beneficial ownership shall be determined in
     accordance with Section 13(d) of the Exchange Act. To the extent that the
     limitation contained in this Section 3(d) applies, the determination of
     whether this Warrant is exercisable (in relation to other securities owned
     by the Holder) and of which a portion of this Warrant is exercisable shall
     be in the sole discretion of such Holder, and the submission of a Notice of
     Exercise shall be deemed to be such Holder's determination of whether this
     Warrant is exercisable (in relation to other securities owned by such
     Holder) and of which portion of this Warrant is exercisable, in each case
     subject to such aggregate percentage limitation, and the Company shall have
     no obligation to verify or confirm the accuracy of such determination.
     Nothing contained herein shall be deemed to restrict the right of a Holder
     to exercise this Warrant into Warrant Shares at such time as such exercise
     will not violate the provisions of this Section 3(d). The provisions of
     this Section 3(d) may be waived by the Holder upon, at the election of the
     Holder, not less than 61 days' prior notice to the Company, and the
     provisions of this Section 3(d) shall continue to apply until such 61st day
     (or such later date, as determined by the Holder, as may be specified in
     such notice of waiver). No exercise of this Warrant in violation of this
     Section 3(d) but otherwise in accordance with this Warrant shall affect the
     status of the Warrant Shares as validly issued, fully-paid and
     nonassessable.

          4.   No Fractional Shares or Scrip. No fractional shares or scrip
               -----------------------------
representing fractional shares shall be issued upon the exercise of this
Warrant. As to any fraction of a share which Holder would otherwise be entitled
to purchase upon such exercise, the Company shall pay a cash adjustment in
respect of such final fraction in an amount equal to such fraction multiplied by
the Exercise Price.

          5.   Charges, Taxes and Expenses. Issuance of certificates for Warrant
               ---------------------------
Shares shall be made without charge to the Holder for any issue or transfer tax
or other incidental expense in respect of the issuance of such certificate, all
of which taxes and expenses shall be paid by the Company, and such certificates
shall be issued in the name of the Holder or in such name or names as may be
directed by the Holder; provided, however, that in the event certificates for
                        --------  -------
Warrant Shares are to be issued in a name other than the name of the Holder,
this

                                       3
<PAGE>

Warrant when surrendered for exercise shall be accompanied by the Assignment
Form attached hereto duly executed by the Holder; and the Company may require,
as a condition thereto, the payment of a sum sufficient to reimburse it for any
transfer tax incidental thereto.

          6.   Closing of Books. The Company will not close its stockholder
               ----------------
books or records in any manner which prevents the timely exercise of this
Warrant.

          7.   Transfer, Division and Combination.
               ----------------------------------

                    (a)  Subject to compliance with any applicable securities
     laws, transfer of this Warrant and all rights hereunder, in whole or in
     part, shall be registered on the books of the Company to be maintained for
     such purpose, upon surrender of this Warrant at the principal office of the
     Company, together with a written assignment of this Warrant substantially
     in the form attached hereto duly executed by the Holder or its agent or
     attorney and funds sufficient to pay any transfer taxes payable upon the
     making of such transfer. In the event that the Holder wishes to transfer a
     portion of this Warrant, the Holder shall transfer at least 100,000 shares
     underlying this Warrant to any such transferee. Upon such surrender and, if
     required, such payment, the Company shall execute and deliver a new Warrant
     or Warrants in the name of the assignee or assignees and in the
     denomination or denominations specified in such instrument of assignment,
     and shall issue to the assignor a new Warrant evidencing the portion of
     this Warrant not so assigned, and this Warrant shall promptly be cancelled.
     A Warrant, if properly assigned, may be exercised by a new holder for the
     purchase of Warrant Shares without having a new Warrant issued.
     Notwithstanding the above, the Holder shall not transfer this Warrant or
     any rights hereunder to any person or entity which is then engaged in a
     business that is in the reasonable judgement of the Company is in direct
     competition with the Company.

                    (b)  This Warrant may be divided or combined with other
     Warrants upon presentation hereof at the aforesaid office of the Company,
     together with a written notice specifying the names and denominations in
     which new Warrants are to be issued, signed by the Holder or its agent or
     attorney. Subject to compliance with Section 7(a), as to any transfer which
     may be involved in such division or combination, the Company shall execute
     and deliver a new Warrant or Warrants in exchange for the Warrant or
     Warrants to be divided or combined in accordance with such notice.

                    (c)  The Company shall prepare, issue and deliver at its own
     expense (other than transfer taxes) the new Warrant or Warrants under this
     Section 7.

                    (d)  The Company agrees to maintain, at its aforesaid
     office, books for the registration and the registration of transfer of the
     Warrants.

          8.   No Rights as Shareholder until Exercise. This Warrant does not
               ---------------------------------------
entitle the Holder to any voting rights or other rights as a shareholder of the
Company prior to the exercise hereof. Upon the surrender of this Warrant and the
payment of the aggregate Exercise Price or by means of a cashless exercise, the
Warrant Shares so purchased shall be and be deemed to be

                                       4
<PAGE>

issued to such Holder as the record owner of such shares as of the close of
business on the later of the date of such surrender or payment.

          9.   Loss, Theft, Destruction or Mutilation of Warrant. The Company
               -------------------------------------------------
covenants that upon receipt by the Company of evidence reasonably satisfactory
to it of the loss, theft, destruction or mutilation of this Warrant or any stock
certificate relating to the Warrant Shares, and in case of loss, theft or
destruction, of indemnity or security reasonably satisfactory to it (which shall
not include the posting of any bond), and upon surrender and cancellation of
such Warrant or stock certificate, if mutilated, the Company will make and
deliver a new Warrant or stock certificate of like tenor and dated as of such
cancellation, in lieu of such Warrant or stock certificate.

          10.  Saturdays, Sundays, Holidays, etc. If the last or appointed day
               ----------------------------------
for the taking of any action or the expiration of any right required or granted
herein shall be a Saturday, Sunday or a legal holiday, then such action may be
taken or such right may be exercised on the next succeeding day not a Saturday,
Sunday or legal holiday.

          11.  Adjustments of Exercise Price and Number of Warrant Shares.
               ----------------------------------------------------------

                    (a)  Stock Splits, etc. The number and kind of securities
                         ------------------
     purchasable upon the exercise of this Warrant and the Exercise Price shall
     be subject to adjustment from time to time upon the happening of any of the
     following. In case the Company shall (i) pay a dividend in shares of Common
     Stock or make a distribution in shares of Common Stock to holders of its
     outstanding Common Stock, (ii) subdivide its outstanding shares of Common
     Stock into a greater number of shares, (iii) combine its outstanding shares
     of Common Stock into a smaller number of shares of Common Stock, or (iv)
     issue any shares of its capital stock in a reclassification of the Common
     Stock, then the number of Warrant Shares purchasable upon exercise of this
     Warrant immediately prior thereto shall be adjusted so that the Holder
     shall be entitled to receive the kind and number of Warrant Shares or other
     securities of the Company which it would have owned or have been entitled
     to receive had such Warrant been exercised in advance thereof. Upon each
     such adjustment of the kind and number of Warrant Shares or other
     securities of the Company which are purchasable hereunder, the Holder shall
     thereafter be entitled to purchase the number of Warrant Shares or other
     securities resulting from such adjustment at an Exercise Price per Warrant
     Share or other security obtained by multiplying the Exercise Price in
     effect immediately prior to such adjustment by the number of Warrant Shares
     purchasable pursuant hereto immediately prior to such adjustment and
     dividing by the number of Warrant Shares or other securities of the Company
     resulting from such adjustment. An adjustment made pursuant to this
     paragraph shall become effective immediately after the effective date of
     such event retroactive to the record date, if any, for such event.

                    (b)  Anti-Dilution Provisions. During the Exercise Period,
                         ------------------------
     the Exercise Price and the number of Warrant Shares issuable hereunder and
     for which this Warrant is then exercisable pursuant to Section 1 hereof
     shall be subject to adjustment from time to time as provided in this
     Section 11(b). In the event that any adjustment of the Exercise Price as
     required herein results in a fraction of a cent, such Exercise Price shall
     be rounded up or down to the nearest cent.

                                       5
<PAGE>

                         (i)    Adjustment of Exercise Price. If and whenever
                                ----------------------------
          solely during the first twelve (12) months of the Exercise Period the
          Company issues or sells, or in accordance with Section 8(b) hereof is
          deemed to have issued or sold, any shares of Common Stock for a
          consideration per share of less than the then current market price
          (the "Base Share Price") or for no consideration (collectively, a
          "Dilutive Issuance"), then effective immediately upon the Dilutive
          Issuance, the Exercise Price will be adjusted in accordance with the
          following formula:

               E'   = E x  O + P/BSP
                         ---------
                           CSDO
               where:

               E'   = the adjusted Exercise Price;
               E    = the then current Exercise Price;
               BSP  = the Base Share Price;
               O    = the number of shares of Common Stock outstanding
                         immediately prior to the Dilutive Issuance;
               P    = the aggregate consideration, calculated as set forth in
                         Section 11(b)(ii) hereof, received by the Company upon
                         such Dilutive Issuance; and
               CSDO = the total number of shares of Common Stock Deemed
                         Outstanding immediately after the Dilutive Issuance.

                         (ii)   Effect on Exercise Price of Certain Events. For
                                ------------------------------------------
          purposes of determining the adjusted Exercise Price under Section
          11(b) hereof, the following will be applicable:

                                (A)  Issuance of Rights or Options. If the
                                     -----------------------------
               Company in any manner issues or grants any warrants, rights or
               options, whether or not immediately exercisable, to subscribe for
               or to purchase Common Stock or other securities exercisable,
               convertible into or exchangeable for Common Stock ("Convertible
               Securities") (such warrants, rights and options to purchase
               Common Stock or Convertible Securities are hereinafter referred
               to as "Options") and the price per share for which Common Stock
               is issuable upon the exercise of such Options is less than the
               Base Share Price ("Below Base Price Options"), then the maximum
               total number of shares of Common Stock issuable upon the exercise
               of all such Below Base Price Options (assuming full exercise,
               conversion or exchange of Convertible Securities, if applicable)
               will, as of the date of the issuance or grant of such Below Base
               Price Options, be deemed to be outstanding and to have been
               issued and sold by the Company for such price per share. For
               purposes of the preceding sentence, the "price per share for
               which Common Stock is issuable upon the exercise of such Below
               Base Price Options" is determined by dividing (i) the total
               amount, if any, received or receivable by the Company as
               consideration for the issuance or granting of

                                       6
<PAGE>

               all such Below Base Price Options, plus the minimum aggregate
               amount of additional consideration, if any, payable to the
               Company upon the exercise of all such Below Base Price Options,
               plus, in the case of Convertible Securities issuable upon the
               exercise of such Below Base Price Options, the minimum aggregate
               amount of additional consideration payable upon the exercise,
               conversion or exchange thereof at the time such Convertible
               Securities first become exercisable, convertible or exchangeable,
               by (ii) the maximum total number of shares of Common Stock
               issuable upon the exercise of all such Below Base Price Options
               (assuming full conversion of Convertible Securities, if
               applicable). No further adjustment to the Exercise Price will be
               made upon the actual issuance of such Common Stock upon the
               exercise of such Below Base Price Options or upon the exercise,
               conversion or exchange of Convertible Securities issuable upon
               exercise of such Below Base Price Options.

                                (B) Issuance of Convertible Securities. If the
                                    ----------------------------------
               Company in any manner issues or sells any Convertible Securities,
               whether or not immediately convertible (other than where the same
               are issuable upon the exercise of Options) and the price per
               share for which Common Stock is issuable upon such exercise,
               conversion or exchange is less than the Base Share Price, then
               the maximum total number of shares of Common Stock issuable upon
               the exercise, conversion or exchange of all such Convertible
               Securities will, as of the date of the issuance of such
               Convertible Securities, be deemed to be outstanding and to have
               been issued and sold by the Company for such price per share. For
               the purposes of the preceding sentence, the "price per share for
               which Common Stock is issuable upon such exercise, conversion or
               exchange" is determined by dividing (i) the total amount, if any,
               received or receivable by the Company as consideration for the
               issuance or sale of all such Convertible Securities, plus the
               minimum aggregate amount of additional consideration, if any,
               payable to the Company upon the exercise, conversion or exchange
               thereof at the time such Convertible Securities first become
               exercisable, convertible or exchangeable, by (ii) the maximum
               total number of shares of Common Stock issuable upon the
               exercise, conversion or exchange of all such Convertible
               Securities. No further adjustment to the Exercise Price will be
               made upon the actual issuance of such Common Stock upon exercise,
               conversion or exchange of such Convertible Securities.

                                (C)  Change in Option Price or Conversion Rate.
                                     -----------------------------------------
               If there is a change at any time in (i) the amount of additional
               consideration payable to the Company upon the exercise of any
               Options; (ii) the amount of additional consideration, if any,
               payable to the Company upon the exercise, conversion or exchange
               of any Convertible Securities; or (iii) the rate at which any
               Convertible Securities are convertible into or exchangeable for
               Common Stock (in each such case, other than under or

                                       7
<PAGE>

               by reason of provisions designed to protect against dilution),
               the Exercise Price in effect at the time of such change will be
               readjusted to the Exercise Price which would have been in effect
               at such time had such Options or Convertible Securities still
               outstanding provided for such changed additional consideration or
               changed conversion rate, as the case may be, at the time
               initially granted, issued or sold.

                                (D)  Treatment of Expired Options and
                                     --------------------------------
               Unexercised Convertible Securities. If, in any case, the total
               ----------------------------------
               number of shares of Common Stock issuable upon exercise of any
               Option or upon exercise, conversion or exchange of any
               Convertible Securities is not, in fact, issued and the rights to
               exercise such Option or to exercise, convert or exchange such
               Convertible Securities shall have expired or terminated, the
               Exercise Price then in effect will be readjusted to the Exercise
               Price which would have been in effect at the time of such
               expiration or termination had such Option or Convertible
               Securities, to the extent outstanding immediately prior to such
               expiration or termination (other than in respect of the actual
               number of shares of Common Stock issued upon exercise or
               conversion thereof), never been issued.

                                (E)  Calculation of Consideration Received. If
                                     -------------------------------------
               any Common Stock, Options or Convertible Securities are issued,
               granted or sold for cash, the consideration received therefor for
               purposes of this Warrant will be the amount received by the
               Company therefor, before deduction of reasonable commissions,
               underwriting discounts or allowances or other reasonable expenses
               paid or incurred by the Company in connection with such issuance,
               grant or sale. In case any Common Stock, Options or Convertible
               Securities are issued or sold for a consideration part or all of
               which shall be other than cash, the amount of the consideration
               other than cash received by the Company will be the fair market
               value of such consideration, except where such consideration
               consists of securities, in which case the amount of consideration
               received by the Company will be the Market Price thereof as of
               the date of receipt. In case any Common Stock, Options or
               Convertible Securities are issued in connection with any merger
               or consolidation in which the Company is the surviving
               corporation, the amount of consideration therefor will be deemed
               to be the fair market value of such portion of the net assets and
               business of the non-surviving corporation as is attributable to
               such Common Stock, Options or Convertible Securities, as the case
               may be. The fair market value of any consideration other than
               cash or securities will be determined in good faith by an
               investment banker or other appropriate expert of national
               reputation selected by the Company and reasonably acceptable to
               the holder hereof, with the costs of such appraisal to be borne
               by the Company.

                                       8
<PAGE>

                                (F)  Exceptions to Adjustment of Exercise Price.
                                     ------------------------------------------
               No adjustment to the Exercise Price will be made (i) upon the
               exercise of this Warrant or any other warrant of this series or
               of any other series issued by the Company in connection with the
               offer and sale of this Company's securities pursuant to the
               Purchase Agreement; (ii) upon the exercise of or conversion of
               any Convertible Securities, options or warrants issued and
               outstanding on the initial issuance date of this Warrant; (iii)
               upon the grant or exercise of any Convertible Securities which
               may hereafter be granted or exercised under any employee benefit
               plan of the Company now existing or to be implemented in the
               future, so long as the issuance of such Convertible Securities is
               approved by a majority of the non-employee members of the Board
               of Directors of the Company or a majority of the members of a
               committee of non-employee directors established for such purpose;
               (iv) upon the issuance of Common Stock or Convertible Securities
               in a public offering, whether or not underwritten; (v) upon the
               issuance of Common Stock or Convertible Securities in any
               transaction of the nature contemplated by Rule 145, promulgated
               under the Securities Act; or (vi) in connection with any
               strategic partnership or joint venture or acquisition (the
               primary purpose of which is not to raise equity capital for the
               Company).

                         (iii)  Notice of Adjustment. Upon the occurrence of any
                                --------------------
          event which requires any adjustment of the Exercise Price, then, and
          in each such case, the Company shall give notice thereof to the holder
          of this Warrant, which notice shall state the Exercise Price resulting
          from such adjustment and the increase or decrease in the number of
          Warrant Shares purchasable at such price upon exercise, setting forth
          in reasonable detail the method of calculation and the facts upon
          which such calculation is based, provided that such notice shall not
          contain any material nonpublic information. Such calculation shall be
          certified by the chief financial officer of the Company.

                         (iv)   Minimum Adjustment of Exercise Price. No
                                ------------------------------------
          adjustment of the Exercise Price shall be made in an amount of less
          than 1% of the Exercise Price in effect at the time such adjustment is
          otherwise required to be made, but any such lesser adjustment shall be
          carried forward and shall be made at the time and together with the
          next subsequent adjustment which, together with any adjustments so
          carried forward, shall amount to not less than 1% of such Exercise
          Price.

                         (v)    Certain Events. If, at any time during the
                                --------------
          Exercise Period, any event occurs of the type contemplated by the
          adjustment provisions of this Section 11 but not expressly provided
          for by such provisions, the Company will give notice of such event as
          provided in Section 11 hereof, and the Company's Board of Directors
          will make an appropriate adjustment in the Exercise Price and the
          number of shares of Common Stock acquirable upon exercise of this
          Warrant

                                       9
<PAGE>

          so that the rights of the holder shall be neither enhanced nor
          diminished by such event.

                         (vi)   Certain Definitions. "Common Stock Deemed
                                -------------------
          Outstanding" shall mean the number of shares of Common Stock actually
          outstanding (not including shares of Common Stock held in the treasury
          of the Company), plus (x) in the case of any adjustment hereunder
          resulting from the issuance of any Options, the maximum total number
          of shares of Common Stock issuable upon the exercise of the Options
          for which the adjustment is required (including any Common Stock
          issuable upon the conversion of Convertible Securities issuable upon
          the exercise of such Options), and (y) in the case of any adjustment
          required hereunder resulting from the issuance of any Convertible
          Securities, the maximum total number of shares of Common Stock
          issuable upon the exercise, conversion or exchange of the Convertible
          Securities for which the adjustment is required, as of the date of
          issuance of such Convertible Securities, if any.

          12.  Reorganization, Reclassification, Merger, Consolidation or
               ----------------------------------------------------------
Disposition of Assets. In case the Company shall reorganize its capital,
---------------------
reclassify its capital stock, consolidate or merge with or into another
corporation (where the Company is not the surviving corporation or where there
is a change in or distribution with respect to the Common Stock of the Company),
or sell, transfer or otherwise dispose of all or substantially all its property,
assets or business to another corporation and, pursuant to the terms of such
reorganization, reclassification, merger, consolidation or disposition of
assets, shares of common stock of the successor or acquiring corporation, or any
cash, shares of stock or other securities or property of any nature whatsoever
(including warrants or other subscription or purchase rights) in addition to or
in lieu of common stock of the successor or acquiring corporation ("Other
Property"), are to be received by or distributed to the holders of Common Stock
of the Company, then the Holder shall have the right thereafter to receive, upon
exercise of this Warrant, the number of shares of Common Stock of the successor
or acquiring corporation or of the Company, if it is the surviving corporation,
and Other Property receivable upon or as a result of such reorganization,
reclassification, merger, consolidation or disposition of assets by a Holder of
the number of shares of Common Stock for which this Warrant is exercisable
immediately prior to such event. In case of any such reorganization,
reclassification, merger, consolidation or disposition of assets, the successor
or acquiring corporation (if other than the Company) shall expressly assume the
due and punctual observance and performance of each and every covenant and
condition of this Warrant to be performed and observed by the Company and all
the obligations and liabilities hereunder, subject to such modifications as may
be deemed appropriate (as determined in good faith by resolution of the Board of
Directors of the Company) in order to provide for adjustments of Warrant Shares
for which this Warrant is exercisable which shall be as nearly equivalent as
practicable to the adjustments provided for in this Section 12. For purposes of
this Section 12, "common stock of the successor or acquiring corporation" shall
include stock of such corporation of any class which is not preferred as to
dividends or assets over any other class of stock of such corporation and which
is not subject to redemption and shall also include any evidences of
indebtedness, shares of stock or other securities which are convertible into or
exchangeable for any such stock,

                                       10
<PAGE>

either immediately or upon the arrival of a specified date or the happening of a
specified event and any warrants or other rights to subscribe for or purchase
any such stock. The foregoing provisions of this Section 12 shall similarly
apply to successive reorganizations, reclassifications, mergers, consolidations
or disposition of assets.

          13.  Voluntary Adjustment by the Company. The Company may at any time
               -----------------------------------
during the term of this Warrant reduce the then current Exercise Price to any
amount and for any period of time deemed appropriate by the Board of Directors
of the Company.

          14.  Notice of Adjustment. Whenever the number of Warrant Shares or
               --------------------
number or kind of securities or other property purchasable upon the exercise of
this Warrant or the Exercise Price is adjusted, as herein provided, the Company
shall promptly mail by registered or certified mail, return receipt requested,
to the Holder notice of such adjustment or adjustments setting forth the number
of Warrant Shares (and other securities or property) purchasable upon the
exercise of this Warrant and the Exercise Price of such Warrant Shares (and
other securities or property) after such adjustment, setting forth a brief
statement of the facts requiring such adjustment and setting forth the
computation by which such adjustment was made. Such notice, in the absence of
manifest error, shall be conclusive evidence of the correctness of such
adjustment.

          15.  Notice of Corporate Action. If at any time:
               --------------------------

                    (a)  the Company shall take a record of the holders of its
     Common Stock for the purpose of entitling them to receive a dividend or
     other distribution, or any right to subscribe for or purchase any evidences
     of its indebtedness, any shares of stock of any class or any other
     securities or property, or to receive any other right, or

                    (b)  there shall be any capital reorganization of the
     Company, any reclassification or recapitalization of the capital stock of
     the Company or any consolidation or merger of the Company with, or any
     sale, transfer or other disposition of all or substantially all the
     property, assets or business of the Company to, another corporation or,

                    (c)  there shall be a voluntary or involuntary dissolution,
     liquidation or winding up of the Company;

then, in any one or more of such cases, the Company shall give to Holder (i) at
least 20 days' prior written notice of the date on which a record date shall be
selected for such dividend, distribution or right or for determining rights to
vote in respect of any such reorganization, reclassification, merger,
consolidation, sale, transfer, disposition, liquidation or winding up, and (ii)
in the case of any such reorganization, reclassification, merger, consolidation,
sale, transfer, disposition, dissolution, liquidation or winding up, at least 20
days' prior written notice of the date when the same shall take place. Such
notice in accordance with the foregoing clause also shall specify (i) the date
on which any such record is to be taken for the purpose of such dividend,
distribution or right, the date on which the holders of Common Stock shall be
entitled to any such dividend, distribution or right, and the amount and
character thereof, and (ii) the date

                                       11
<PAGE>

on which any such reorganization, reclassification, merger, consolidation, sale,
transfer, disposition, dissolution, liquidation or winding up is to take place
and the time, if any such time is to be fixed, as of which the holders of Common
Stock shall be entitled to exchange their Warrant Shares for securities or other
property deliverable upon such disposition, dissolution, liquidation or winding
up. Each such written notice shall be sufficiently given if addressed to Holder
at the last address of Holder appearing on the books of the Company and
delivered in accordance with Section 17(d).

          16.  Authorized Shares. The Company covenants that during the period
               -----------------
the Warrant is outstanding, it will reserve from its authorized and unissued
Common Stock a sufficient number of shares to provide for the issuance of the
Warrant Shares upon the exercise of any purchase rights under this Warrant. The
Company further covenants that its issuance of this Warrant shall constitute
full authority to its officers who are charged with the duty of executing stock
certificates to execute and issue the necessary certificates for the Warrant
Shares upon the exercise of the purchase rights under this Warrant. The Company
will take all such reasonable action as may be necessary to assure that such
Warrant Shares may be issued as provided herein without violation of any
applicable law or regulation, or of any requirements of the Principal Market
upon which the Common Stock may be listed.

                    The Company shall not by any action, including, without
limitation, amending its certificate of incorporation or 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 of this Warrant, but will at all
times in good faith assist in the carrying out of all such terms and in the
taking of all such actions as may be necessary or appropriate to protect the
rights of Holder against impairment. Without limiting the generality of the
foregoing, the Company will (a) not increase the par value of any Warrant Shares
above the amount payable therefor upon such exercise immediately prior to such
increase in par value, (b) take all such action as may be necessary or
appropriate in order that the Company may validly and legally issue fully paid
and nonassessable Warrant Shares upon the exercise of this Warrant, and (c) use
commercially reasonable efforts to obtain all such authorizations, exemptions or
consents from any public regulatory body having jurisdiction thereof as may be
necessary to enable the Company to perform its obligations under this Warrant.

                    Before taking any action which would result in an adjustment
in the number of Warrant Shares for which this Warrant is exercisable or in the
Exercise Price, the Company shall obtain all such authorizations or exemptions
thereof, or consents thereto, as may be necessary from any public regulatory
body or bodies having jurisdiction thereof.

          17.  Miscellaneous.
               -------------

                    (a)  Jurisdiction. This Warrant shall constitute a contract
                         ------------
     under the laws of New York, without regard to its conflict of law,
     principles or rules, and be subject to arbitration pursuant to the terms
     set forth in the Purchase Agreement.

                                       12
<PAGE>

                    (b)  Restrictions. The Holder acknowledges that the Warrant
                         ------------
     Shares acquired upon the exercise of this Warrant, if not registered, will
     have restrictions upon resale imposed by state and federal securities laws.

                    (c)  Nonwaiver and Expenses. No course of dealing or any
                         ----------------------
     delay or failure to exercise any right hereunder on the part of Holder
     shall operate as a waiver of such right or otherwise prejudice Holder's
     rights, powers or remedies, notwithstanding all rights hereunder terminate
     on the Termination Date. If the Company willfully and knowingly fails to
     comply with any provision of this Warrant, which results in any material
     damages to the Holder, the Company shall pay to Holder such amounts as
     shall be sufficient to cover any costs and expenses including, but not
     limited to, reasonable attorneys' fees, including those of appellate
     proceedings, incurred by Holder in collecting any amounts due pursuant
     hereto or in otherwise enforcing any of its rights, powers or remedies
     hereunder.

                    (d)  Notices. Any notice, request or other document required
                         -------
     or permitted to be given or delivered to the Holder by the Company shall be
     delivered in accordance with the notice provisions of the Purchase
     Agreement.

                    (e)  Limitation of Liability. No provision hereof, in the
                         -----------------------
     absence of affirmative action by Holder to purchase Warrant Shares, and no
     enumeration herein of the rights or privileges of Holder, shall give rise
     to any liability of Holder for the purchase price of any Common Stock or as
     a stockholder of the Company, whether such liability is asserted by the
     Company or by creditors of the Company.

                    (f)  Remedies. Holder, in addition to being entitled to
                         --------
     exercise all rights granted by law, including recovery of damages, will be
     entitled to specific performance of its rights under this Warrant. The
     Company agrees that monetary damages would not be adequate compensation for
     any loss incurred by reason of a breach by it of the provisions of this
     Warrant and hereby agrees to waive the defense in any action for specific
     performance that a remedy at law would be adequate.

                    (g)  Successors and Assigns. Subject to applicable
                         -----------------------
     securities laws, this Warrant and the rights and obligations evidenced
     hereby shall inure to the benefit of and be binding upon the successors of
     the Company and the successors and permitted assigns of Holder. The
     provisions of this Warrant are intended to be for the benefit of all
     Holders from time to time of this Warrant and shall be enforceable by any
     such Holder or holder of Warrant Shares.

                    (h)  Amendment. This Warrant may be modified or amended or
                         ---------
     the provisions hereof waived with the written consent of the Company and
     the Holder.

                    (i)  Severability. Wherever possible, each provision of this
                         ------------
     Warrant shall be interpreted in such manner as to be effective and valid
     under applicable law, but if any provision of this Warrant shall be
     prohibited by or invalid under applicable law, such provision shall be
     ineffective to the extent of such prohibition or invalidity, without
     invalidating the remainder of such provisions or the remaining provisions
     of this Warrant.

                                       13
<PAGE>

                    (j)  Headings. The headings used in this Warrant are for the
                         --------
     convenience of reference only and shall not, for any purpose, be deemed a
     part of this Warrant.

                                       14
<PAGE>

          IN WITNESS WHEREOF, the Company has caused this Warrant to be executed
by its officer thereunto duly authorized.


Dated: June __, 2001
                                   DATA RACE, INC.



                                   By:
                                      ----------------------------------------
                                       Michael McDonnell, President & CEO


                                       15
<PAGE>

                              NOTICE OF EXERCISE

To:  Data Race, Inc.


          (1)  The undersigned hereby elects to purchase ________ Warrant Shares
(the "Common Stock"), of Data Race, Inc. pursuant to the terms of the attached
Warrant, and tenders herewith payment of the exercise price in full, together
with all applicable transfer taxes, if any.

          (2)  Please issue a certificate or certificates representing said
Warrant Shares in the name of the undersigned or in such other name as is
specified below:

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


The Warrant Shares shall be delivered to the following:


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

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

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



                                   [PURCHASER]


                                   By:
                                       ------------------------------
                                        Name:
                                        Title:

                                   Dated:
                                         ----------------------------
<PAGE>

                  NOTICE OF EXERCISE OF COMMON STOCK WARRANT
                   PURSUANT TO CASHLESS EXERCISE PROVISIONS

To: Data Race, Inc.

Aggregate Price of Warrant Before Exercise:  $__________
Aggregate Price Being Exercised:  $__________
Exercise Price:  $__________ per share
Number of Shares of Common Stock to be Issued Under this Notice: __________
Remaining Aggregate Price (if any) After Issuance:  $__________


Gentlemen:

          The undersigned, registered Holder of the Warrant delivered herewith,
hereby irrevocably exercises such Warrant for, and purchases thereunder, shares
of the Common Stock of Data Race, Inc., a Texas corporation, as provided below.
Capitalized terms used herein, unless otherwise defined herein, shall have the
meanings given in the Warrant. The portion of the Exercise Price (as defined in
the Warrant) to be applied toward the purchase of Common Stock pursuant to this
Notice of Exercise is $_______, thereby leaving a remaining Exercise Price (if
any) equal to $________. Such exercise shall be pursuant to the cashless
exercise provisions of Section 3 of the Warrant; therefore, Holder makes no
payment with this Notice of Exercise. The number of shares to be issued pursuant
to this exercise shall be determined by reference to the formula in Section 3 of
the Warrant which, by reference to Section 3, requires the use of the high and
low trading price of the Company's Common Stock on the Trading Day preceding the
date of such election. The high and low trading price of the Company's Common
Stock has been determined by Holder to be $______ and $_________, respectively,
which figure is acceptable to Holder for calculations of the number of shares of
Common Stock issuable pursuant to this Notice of Exercise. Holder requests that
the certificates for the purchased shares of Common Stock be issued in the name
of _________________________ and delivered to _________________________________.
To the extent the foregoing exercise is for less than the full Aggregate Price
of the Warrant, a replacement Warrant representing the remainder of the
Aggregate Price (and otherwise of like form, tenor and effect) shall be
delivered to Holder along with the share certificate evidencing the Common Stock
issued in response to this Notice of Exercise.

                                    [Purchaser]


                                    By:
                                       ------------------------------
                                        Name:
                                        Title:

                                    Date:

                                     NOTE
          The execution to the foregoing Notice of Exercise must exactly
correspond to the name of the Holder on the Warrant

                                       2
<PAGE>

                                ASSIGNMENT FORM

                   (To assign the foregoing warrant, execute
                  this form and supply required information.
                Do not use this form to exercise the warrant.)



          FOR VALUE RECEIVED, the foregoing Warrant and all rights evidenced
thereby are hereby assigned to


                                                whose address is
-----------------------------------------------

-----------------------------------------------------------------.




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

                                   Dated:
                                         ---------------, ------


               Holder's Signature:
                                  ------------------------------

               Holder's Address:
                                  ------------------------------


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


Signature Guaranteed:
                     ----------------------------------------


NOTE: The signature to this Assignment Form must correspond with the name as it
appears on the face of the Warrant, without alteration or enlargement or any
change whatsoever, and must be guaranteed by a bank or trust company. Officers
of corporations and those acting in an fiduciary or other representative
capacity should file proper evidence of authority to assign the foregoing
Warrant.