EXHIBIT 4.21


THIS  WARRANT  AND THE STOCK  ISSUABLE  UPON THE  EXERCISE  HEREOF HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"),  AND CAN BE
TRANSFERRED  ONLY IN COMPLIANCE  WITH THE ACT AND  APPLICABLE  STATE  SECURITIES
LAWS. THIS WARRANT AND SUCH SECURITIES MAY NOT BE SOLD,  TRANSFERRED OR ASSIGNED
IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT, UNLESS, IN THE OPINION OF
COUNSEL FOR THE COMPANY OR COUNSEL FOR THE REGISTERED  HOLDER (WHICH SHALL BE IN
FORM AND FROM SUCH COUNSEL AS SHALL BE REASONABLY  SATISFACTORY TO THE COMPANY),
SUCH REGISTRATION IS NOT THEN REQUIRED.

                            U.S. Wireless Data, Inc.
                          2200 Powell Street, Suite 800
                          Emeryville, California 94608

                          COMMON STOCK PURCHASE WARRANT

Warrant No. ___________                   Right to Purchase _____________
                                          shares of No Par Value Common
                                          Stock (subject to adjustment)


Date of Issuance:  As of _______________, 199__
Expiration Date:   On or before _____________, 200__

         THIS CERTIFIES THAT, for value received,

_____________________________________________ ("Purchaser"),

or permitted transferees in accordance with Section 12 hereof, or its registered
assigns  (the  "Registered  Holder" or  "Registered  Holders"),  is  entitled to
purchase from U.S. Wireless Data, Inc., a Colorado  corporation (the "Company"),
the  number  of  shares of common  stock,  no par value per share  (the  "Common
Stock"),  of the  Company set forth  above,  subject to  adjustment  pursuant to
Section 4 hereof, at the price of ______________________  ($_________) per share
of Common  Stock,  subject  to  adjustment  pursuant  to  Section 3 hereof  (the
"Exercise  Price").  These purchase rights are granted  pursuant to that certain
Agreement  dated as of  _______________________,  1998,  between the Company and
Purchaser (the "Purchase Agreement"), subject to the following provisions:

<PAGE>
                                    SECTION 1
                               CERTAIN DEFINITIONS

         As used in this  Warrant,  the  following  terms have the  meanings set
forth below:

         "Agreement"  is the Series A  Preferred  Stock  Modification  Agreement
dated as of September 17, 1998, between the Company and Purchaser.

         "Agreement Date" means the date of the Agreement.

         "Commission" means the Securities and Exchange Commission.

         "Common Stock" means the Company's Common Stock, no par value per share

         "Common Stock Deemed  Outstanding" means the number of shares of Common
Stock  actually  outstanding  at such time,  plus the number of shares of Common
Stock deemed to be  outstanding  at any given time pursuant to Section 3 of this
Warrant.

         "Convertible  Securities" or "Convertible Security" means any rights or
options which are exercisable to purchase,  or convertible into, Common Stock or
any stock or other securities convertible into or exchangeable for Common Stock.

         "Date of  Issuance"  is the date set  forth on the  front  page of this
Warrant,  and the terms  "date  hereof,"  "date of this  Warrant,"  and  similar
expressions shall be deemed to refer to the Date of Issuance.

         "Exercise  Period"  means the period of time  commencing at 12:01 A.M.,
Eastern Time, on the Date of Issuance and ending at 5:00 P.M.,  Eastern Time, on
the Expiration Date, as set forth on the front page of this Warrant.

         "Fair  Value"  means a value  determined  in good faith by the Board of
Directors of the Company.  Anytime a Fair Value is required to be determined for
purposes of this Warrant,  a certificate  executed by an appropriate  officer of
the Company shall be prepared and delivered to the Registered  Holder to reflect
the action taken by the Board of Directors to determine such Fair Value.

         "Market  Price"  means,  as to any  security  immediately  transferable
without restriction,  the average of the closing prices of such security's sales
on the principal domestic  securities exchange on which such security may at the
time be listed, or, if there have been no sales on any such exchange on any day,
the average of the highest bid and lowest asked prices on all such  exchanges at
the end of such  day,  or, if on any day such  security  is not so  listed,  the
average of the bid and asked prices  quoted on Nasdaq as of the close of trading
in New York City on such day, in each such case  averaged  over a period of five
(5) consecutive days
                                       -2-
<PAGE>
consisting of the business day immediately  preceding the day as of which Market
Price is being  determined and the four (4)  consecutive  business days prior to
such day;  provided that if such  security is listed on any  principal  domestic
securities  exchange or quoted on Nasdaq, the terms "business day" and "business
days" means a day or days,  as  applicable,  on which such exchange or Nasdaq is
open for trading or quotation,  as the case may be, notwithstanding  whether any
quotation  is  available on any  particular  business day and, if not,  then the
Market  Price shall be  determined  based upon those  remaining  days during the
aforesaid  5-day period for which  quotations are available.  If any security is
not  immediately  transferable  without  restriction,  or is not  listed  on any
principal  domestic  securities  exchange or quoted on Nasdaq,  the Market Price
shall be the Fair Value thereof.

         "Nasdaq"  means the National  Market  System or the Small Cap Market of
the Nasdaq Stock Market, or the OTC Electronic  Bulletin Board, or any successor
interdealer  quotation  systems having  substantially  the same listing criteria
that may in the future be used generally by members of the National  Association
of Securities Dealers, Inc. for over-the-counter transactions in securities.

         "Person" means an individual, a partnership,  a corporation, a trust, a
joint venture, an unincorporated  organization,  a government and any department
and agency thereof.

         "Series A Preferred  Stock" means that Series A Cumulative  Convertible
Redeemable  Preferred  Stock of the Company which is  outstanding on the Date of
Issuance.

         "Six Percent Convertible Debentures" means the Company's 6% Convertible
Subordinated  Debentures Due July 21, 2000,  originally  issued  effective as of
July 22, 1998.

         "Stock"  means  shares of the  Company's  Common Stock  authorized  but
unissued as of the Date of Issuance,  issued or issuable  upon  exercise of this
Warrant;  provided that if there is a change such that the securities  issued or
issuable  upon  exercise of this  Warrant are issued by an entity other than the
Company,  or there is a change in the class of securities so issuable,  then the
term "Stock" shall mean shares of any security  issued or issuable upon exercise
of the Warrant if such  security  is issuable in shares,  or shall mean units of
any such  security  issued or  issuable,  if such  security  is not  issuable in
shares.

         "Warrant" and "Warrants"  means this Warrant and all warrants issued or
issuable in  exchange or  substitution  for this  Warrant  pursuant to the terms
hereof.

                                    SECTION 2
                               EXERCISE OF WARRANT

     2.1 Exercise Period.  The Registered  Holder may exercise this Warrant,  in
whole or in part, at any time and from time to time, during the Exercise Period,
and the

                                       -3-

<PAGE>
exercise  hereof may be for such whole number of Stock as the Registered  Holder
may, in its sole discretion, decide.

     2.2 Exercise Procedure.

          (a) This Warrant  shall be deemed to have been  exercised at such time
     as the Company  has  received  all of the  following  items (the  "Exercise
     Date"):

               (i) A completed Exercise Agreement,  as described below, executed
          by  the  Person   exercising  all  or  part  of  the  purchase  rights
          represented by this Warrant (the "Purchaser");

               (ii) This  Warrant  (subject  to delivery by the Company of a new
          Warrant  with  respect to any  unexercised  portion,  as  provided  in
          Paragraph (b) of Subsection 2.2);

               (iii)  If  this  Warrant  is not  registered  in the  name of the
          Purchaser, an Assignment or Assignments  substantially in the form set
          forth as Exhibit II hereto,  evidencing the assignment of this Warrant
          to the Purchaser; and

               (iv) If the Purchaser has elected not to make a Cashless Exercise
          as provided in Paragraph  (b) of this  Subsection  2.2, a certified or
          bank  check or other  certified  funds  payable  to the  Company in an
          amount equal to the product of the Exercise  Price  multiplied  by the
          number of Stock being purchased upon such exercise.

          (b)  Certificates  for Stock  purchased  upon exercise of this Warrant
     shall be delivered by the Company to the Purchaser within five (5) business
     days after the Exercise Date. However, if the Purchaser has elected to make
     a  "Cashless  Exercise"  as herein  described,  the Company  shall  deliver
     certificates for the number of shares that results from  subtracting,  from
     the total number of Stock otherwise  deliverable upon exercise,  the number
     of Stock whose value,  calculated  using the Market Price,  is equal to the
     value of the payment  otherwise  required for exercise by Paragraph (a)(iv)
     of this  Subsection  2.2.  Unless  this  Warrant  has expired or all of the
     purchase rights represented hereby have been exercised,  the Company shall,
     in  addition  to  certificates  for Stock,  prepare  upon  exercise of this
     Warrant, a new Warrant representing the rights formerly represented by this
     Warrant that have not expired or been exercised.  The Company shall, within
     five (5) business days after the Exercise Date, deliver such new Warrant to
     the Persons designated for delivery in the Exercise Agreement.

          (c) Except as otherwise  required or permitted by the exercise of this
     Warrant under the provisions of Paragraph (b) of this  Subsection  2.2, the
     Stock  issuable  upon the exercise of this Warrant  shall be deemed to have
     been issued to the Purchaser on the

                                       -4-
<PAGE>
     Exercise Date,  and the Purchaser  shall be deemed for all purposes to have
     become the record holder of such Stock on the Exercise Date.

          (d) The  issuance  of  certificates  for Stock upon  exercise  of this
     Warrant  shall be made  without  charge  to the  Registered  Holder  or the
     Purchaser  for any  issuance  tax in  respect  thereof  or any  other  cost
     incurred by the Company in  connection  with such  exercise and the related
     issuance of Stock.

          (e) The  Company  shall not close its books for the  transfer  of this
     Warrant  or of any Stock in any  manner  that  interferes  with the  timely
     exercise of this Warrant. The Company shall from time to time take all such
     action as may be  necessary  to assure  that the par value per share of the
     unissued  Stock is at all times  equal to or less than the  Exercise  Price
     then in effect.

     2.3 Exercise  Agreement.  The Exercise  Agreement shall be substantially in
the form set forth as Exhibit I hereto, except that if Stock is not to be issued
in the name of the  Registered  Holder of this Warrant,  the Exercise  Agreement
shall also state the name of the  Persons to whom Stock is to be issued,  and if
the number of Stock  purchased  does not include  all of such Stock  purchasable
hereunder,  it shall also state the name of the Persons to whom new Warrants for
the  unexercised  portion  of the  rights  hereunder  are to be  delivered.  Any
transfer of Stock to a person other than a prior  Registered  Holder shall occur
only in compliance with the provisions  regarding  transfer contained in Section
12 of this Warrant.

     2.4 Fractional Portions of Stock. If a fractional portion of Stock would be
issuable upon exercise of the rights  represented  by this Warrant,  the Company
shall,  within three (3) business days after the Exercise  Date,  deliver to the
Purchaser a check payable to the Purchaser,  in lieu of such fractional  portion
of Stock, in an amount equal to the Market Price of such  fractional  portion of
Stock as of the close of business on the Exercise Date.

                                    SECTION 3
                                 EXERCISE PRICE

     3.1 General.

          (a) The  initial  Exercise  Price of this  Warrant is set forth on the
     front  page of this  Warrant.  In order to prevent  dilution  of the rights
     granted under this Warrant under the  circumstances  set forth herein,  the
     Exercise Price shall be subject to adjustment from time to time pursuant to
     this Section 3.

          (b) If and whenever the Company issues or sells, or in accordance with
     Subsection  3.3 is deemed to have issued or sold,  any shares of its Common
     Stock for a  consideration  per share less than the Market  Price in effect
     immediately prior to the time of such issuance or sale (except as otherwise
     provided by Subsection 3.2), then immediately


                                       -5-
<PAGE>
     upon each such issuance or sale,  the Exercise  Price shall be reduced to a
     price  determined by multiplying  the Exercise Price in effect  immediately
     prior to the issuance or sale by a fraction,  the  numerator of which shall
     be the sum of (i) the number of shares of Common Stock actually outstanding
     prior to the  issuance  or sale,  and (ii) the  number  of shares of Common
     Stock that the minimum aggregate amount receivable by the Company upon such
     issuance or sale on that occasion  would  purchase at the initial  Exercise
     Price, and the denominator of which shall be the number of shares of Common
     Stock  actually  outstanding  and Common  Stock  Deemed  Outstanding  under
     Subsection 3.3 immediately after such issuance or sale.

     3.2 No Adjustments  in Certain  Cases.  No adjustment to the Exercise Price
under Paragraph (b) of Subsection 3.1 or under  Subsection 3.3, or to the number
of shares issuable upon exercise of this Warrant under Section 4 shall be made:

          (a) for the existence of, and any exercise, conversion or issuance of,
     any Common Stock or other  security of the Company  under (i) the Warrants;
     (ii) any option,  warrant,  or other right to purchase Common Stock that is
     outstanding  on the  Agreement  Date,  (iii) any  option  issued  under the
     Company's 1992 Stock Option Plan, as in effect on the Agreement  Date, (iv)
     any  option  or  contract  right  issued  as  compensation  to an  officer,
     director,  employee or  consultant  of the  Company,  whether or not issued
     pursuant to the 1992 Stock  Option Plan;  (v) the Series A Preferred  Stock
     and the issuance of Common Stock as  dividends or upon  conversion  of, the
     Series A Preferred Stock; (vi) the Six Percent  Convertible  Debentures and
     the issuance of Common Stock as interest on, or upon conversion of, the Six
     Percent Convertible Debentures;  or (vii) upon the issuance of Common Stock
     or other  Convertible  Securities as a result of the exercise or conversion
     of any  option or warrant  or other  right of the Holder to acquire  Common
     Stock of Convertible  Securities of the Company,  whether outstanding as of
     the Agreement Date or issued at any time subsequent to the Agreement date.

          (b) upon the issuance of Common Stock upon  exercise or  conversion of
     any option,  warrant or other  right or  Convertible  Securities  for which
     adjustments  have  previously  been  made  upon  issuance  of such  option,
     warrant, right or Convertible Securities.

     3.3 Effect on Exercise Price of Certain Events. For purposes of determining
the adjusted Exercise Price under Subsection 3.1 above, the following provisions
shall be applicable:

          (a)  Issuance  of Rights  and  Options.  If the  Company in any manner
     grants any rights or options to subscribe  for or to purchase  Common Stock
     or any  stock or other  securities  convertible  into or  exchangeable  for
     Common Stock (such rights or options being herein called "Options" and such
     convertible  or  exchangeable  stock  or  securities  being  herein  called
     "Convertible Securities") and the price per share for which Common Stock is
     issuable  upon the exercise of such Options or upon  conversion or exchange
     of such Convertible

                                       -6-
<PAGE>
     Securities is less than the Market Price in effect immediately prior to the
     time of the  granting of such  Options,  then the total  maximum  number of
     shares of Common Stock  issuable  upon the exercise of such Options or upon
     conversion  or exchange  of the total  maximum  amount of such  Convertible
     Securities  shall be deemed to be  outstanding  and to have been issued and
     sold by the  Company  for  such  price  per  share.  For  purposes  of this
     paragraph,  the "price per share for which  Common  Stock is issuable  upon
     exercise of such Options or upon conversion or exchange of such Convertible
     Securities"  shall be determined by dividing (i) the total amount,  if any,
     received by the Company as  consideration  for the granting of such Options
     plus the minimum  aggregate amount of additional  consideration  payable to
     the Company upon  exercise of all such Options plus, in the case of Options
     that relate to the Convertible Securities,  the minimum aggregate amount of
     additional  consideration,   if  any,  payable  to  the  Company  upon  the
     conversion or exchange of such  Convertible  Securities,  by (ii) the total
     maximum number of shares of Common Stock issuable upon the exercise of such
     Options and upon the conversion or exchange of all  Convertible  Securities
     issuable upon the exercise of such Options.

          (b) Issuance of Convertible  Securities.  If the Company in any manner
     issues or sells  any  Convertible  Securities,  and the price per share for
     which  Common  Stock  is  issuable  upon  conversion  or  exchange  or such
     Convertible  Securities is less than the Market Price in effect immediately
     prior to the time of such  issuance  or sale,  then the  maximum  number of
     shares of Common Stock  issuable  upon  conversion  or exchange of all such
     Convertible  Securities  shall be deemed to be outstanding and to have been
     issued and sold by the  Company for such price per share.  For  purposes of
     this  paragraph,  the "price per share for which  Common  Stock is issuable
     upon such  conversion or exchange"  shall be determined by dividing (i) the
     total amount received by the Company as  consideration  for the issuance or
     sale of such Convertible  Securities,  plus the minimum aggregate amount of
     additional  consideration,   if  any,  payable  to  the  Company  upon  the
     conversion or exchange thereof,  by (ii) the total maximum number of shares
     of Common  Stock  issuable  upon the  conversion  or  exchange  of all such
     Convertible Securities.

          (c) Change in Option Price and  Conversion  Rate.  If any change shall
     occur in the price per share provided for in any of the options,  rights or
     warrants  referred to in Paragraph  (a) of this  Subsection  3.3, or in the
     price  per  share  at  which  the  Convertible  Securities  referred  to in
     Paragraph (b) of this Subsection 3.3 are convertible or exchangeable,  such
     options,  rights or warrants or conversion or exchange rights,  as the case
     may be, shall be deemed to have expired or terminated on the date when such
     price change became  effective in respect of shares not theretofore  issued
     pursuant to the exercise or conversion or exchange thereof, and the Company
     shall be  deemed to have  issued  upon  such  date new  options,  rights or
     warrants  or  Convertible  Securities  at the new price in  respect  of the
     number of shares  issuable  upon the  exercise of such  options,  rights or
     warrants or the conversion or exchange of such Convertible Securities.


                                       -7-
<PAGE>
          (d)  Calculation  of  Consideration  Received.  If any  Common  Stock,
     Options,  or  Convertible  Securities  are issued or sold or deemed to have
     been issued or sold or consideration that includes  unrestricted cash, then
     the amount of cash consideration  actually received by the Company shall be
     deemed  to be the full  monetary  value of the  unrestricted  cash  portion
     thereof. If any Common Stock, Options or Convertible  Securities are issued
     or sold or deemed to have been issued or sold for a  consideration  part or
     all of  which is other  than  unrestricted  cash,  then the  amount  of the
     consideration other than unrestricted cash received by the Company shall be
     deemed to be the Fair Value of such consideration.

          (e)  Integrated  Transactions.  If any Option is issued in  connection
     with the  issuance or sale of other  securities  of the  Company,  together
     compromising one integrated  transaction in which no specific consideration
     is  allocated  to such Option by the parties  thereto,  the Option shall be
     deemed to have been issued without consideration.

          (f)  Treasury  Shares.  The  number of shares of Common  Stock  Deemed
     Outstanding  at any given time shall not include shares owned or held by or
     for the account of the Company,  and the disposition of any shares so owned
     or held shall be considered an issuance or sale of Common Stock.

          (g) Readjustment Upon Expiration of Options or Convertible Securities.
     Upon the expiration of any of the options,  warrants or rights  referred to
     in Paragraph  (a) of this  Subsection  3.3, or the  Convertible  Securities
     referred to in  Paragraph  (b) of this  Subsection  3.3,  if such  options,
     warrants,  rights or Convertible  Securities shall not have been exercised,
     converted  or  exchanged,  as the case may be, the Exercise  Price,  to the
     extent that Warrants have not been exercised,  shall, upon such expiration,
     be  readjusted  and  shall  thereafter  be set (A) if any of such  options,
     warrants or rights have been exercised or such Convertible  Securities have
     been  converted or  exchanged,  as the case may be, at a level at which the
     Exercise  Price would have been if originally  adjusted on the basis of (i)
     the fact that the only shares of Common  Stock so issued were the shares of
     Common  Stock,  if any,  actually  issued or sold upon the exercise of such
     options,  warrants  or  rights  or  the  conversion  or  exchange  of  such
     Convertible  Securities and (ii) such shares of Common Stock,  if any, were
     issued or sold for the  consideration  actually received by the Company for
     the  issuance,  sale or grant  of all such  options,  warrants,  rights  or
     Convertible  Securities,  whether or not exercised,  plus the consideration
     actually received by the Company upon the exercise,  conversion or exchange
     of such options, warrants, rights or Convertible Securities, or (B) if none
     of such options, warrants or rights have been exercised or such Convertible
     Securities have been converted or exchanged, as the case may be, at a level
     at which the Exercise Price would have been if such original adjustment had
     not been required;  provided, however, that no such readjustment shall have
     the effect of increasing the Exercise Price in effect  immediately prior to
     such readjustment by a proportion  greater than the aggregate  proportional
     adjustment  originally made upon the issue,  sale or grant of such options,
     warrants, rights, or Convertible Securities.


                                       -8-

<PAGE>
     3.4 Subdivision and Combination of Common Stock;  Stock  Dividends.  If the
Company  shall at any time after the date  hereof (a) issue any shares of Common
Stock or  Convertible  Securities,  or any rights to  purchase  Common  Stock or
Convertible  Securities as a dividend upon Common Stock, (b) issue any shares of
Common  Stock  in  subdivision   of  outstanding   shares  of  Common  Stock  by
reclassification, stock split or otherwise, or (c) combine outstanding shares of
Common Stock by  reclassification,  reverse stock split or  otherwise,  then the
Exercise  Price  that  would  apply if  purchase  rights  hereunder  were  being
exercised  immediately  prior to such action by the Company shall be adjusted by
multiplying  it by a  fraction,  the  numerator  of which shall be the number of
shares of Common Stock Deemed  Outstanding  immediately  prior to such dividend,
subdivision or combination  and the  denominator of which shall be the number of
shares of Common  Stock  Deemed  Outstanding  immediately  after such  dividend,
subdivision or combination.

     3.5 Certain  Dividends  and  Distributions.  If the Company shall declare a
dividend or  distribution  upon the Common Stock payable  otherwise  than out of
earnings  or earned  surplus  and  otherwise  than in Common  Stock,  Options or
Convertible Securities,  the Exercise Price shall be reduced by an amount equal,
in the case of a dividend or distribution in cash, to the amount thereof payable
per  share  of the  Common  Stock  or,  in the  case of any  other  dividend  or
distribution,  to the Fair Value of such dividend or  distribution  per share of
Common Stock.  For purposes of the foregoing,  a dividend or distribution  other
than in cash shall be considered  payable out of earnings or earned surplus only
to the extent that such  earnings or earned  surplus are charged an amount equal
to the Fair Value of such dividend or  distribution.  Such reductions shall take
effect as of the date on which a record is taken for the purpose of such divided
or distribution,  or, if a record is not taken, the date as of which the holders
of Common Stock of record  entitled to such dividend or  distribution  are to be
determined.  The adjustment called for by this Subsection 3.5 shall not apply to
dividends  payable  on the  preferred  stock  issuable  upon  conversion  of the
Debentures.

     3.6  Manner of  Calculating  Adjustments;  No De Minimis  Adjustments.  The
calculation  of each  adjustment of the Exercise Price shall be made accurate to
the nearest ten-  thousandth.  No adjustment of the Exercise Price shall be made
if the amount of such adjustment  would be less than one cent per share. In such
case any adjustment that otherwise would be required to be made shall be carried
forward  and  shall be made at the time and  together  with the next  subsequent
adjustment that, together with any adjustment or adjustments so carried forward,
shall amount to not less than one cent per share.

                                    SECTION 4
              ADJUSTMENT OF NUMBER OF STOCK ISSUABLE UPON EXERCISE

         Upon each reduction of the Exercise Price pursuant to Section 3 hereof,
the  Registered  Holder  shall  thereafter  (until  another such  reduction)  be
entitled  to  purchase,  at the  Exercise  Price in effect on the date  purchase
rights under this Warrant are exercised,  the number of Stock, calculated to the
nearest whole number of Stock, determined by (a)


                                       -9-
<PAGE>
multiplying the number of Stock purchasable  hereunder  immediately prior to the
reduction of the  Exercise  Price by the  Exercise  Price in effect  immediately
prior to such  reduction,  and (b)  dividing  the  product  so  obtained  by the
Exercise Price in effect on the date of such exercise.

                                    SECTION 5
                   EFFECT OF REORGANIZATION, RECLASSIFICATION,
                CONSOLIDATION, MERGER, SALE OR OTHER DISPOSITION

         If at any time while this  Warrant is  outstanding  there  shall be any
reorganization  or  reclassification  of the capital stock of the Company (other
than a subdivision  or  combination  of shares  provided for in  Subsection  3.4
hereof),  any  consideration  or merger of the Company with another  corporation
(other  than a  consolidation  or merger in which the  Company is the  surviving
entity and which does not result in any change in the Common Stock), or any sale
or other disposition by the Company of all or substantially all of its assets to
any other corporation, then the Registered Holder shall thereafter upon exercise
of this  Warrant be  entitled  to  receive  the Stock and other  securities  and
property  of  the  Company,  or of  the  successor  corporation  resulting  from
consolidation or merger,  as the case may be, to which Purchasers of Stock would
have been  entitled  upon such  reorganization,  reclas-  sification  of capital
stock, consolidation, merger, sale or other disposition if this Warrant has been
exercised   immediately   prior   to  such   reorganization,   reclassification,
consolidation,  merger, sale or other disposition. In any such case, appropriate
adjustment  (as  determined  in good  faith  by the  Board of  Directors  of the
Company)  shall be made in the  application  of the provisions set forth in this
Warrant with respect to the rights and interests  thereafter  of the  Registered
Holder to the end that the provisions set forth in this Warrant shall thereafter
be  applicable,  as near as reasonably may be, in relation to any Stock or other
securities or property  thereafter  deliverable  upon the exercise  hereof as if
this  Warrant  had been  exercised  immediately  prior  to such  reorganization,
reclassification  of  capital  stock,  consolidation,   merger,  sale  or  other
disposition  and the  Registered  Holder hereof had carried out the terms of the
exchange as provided  for by such  reorganization,  reclassification  of capital
stock,  consolidation,  merger,  sale  or  other  disposition.  If in  any  such
reorganization,  reclassification of capital stock, consolidation,  merger, sale
or other  disposition,  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  deliverable  from  exercise of
this  Warrant,  any such  issue  shall be  treated  as an issue of Common  Stock
covered by the  provisions  of  Section 3, with the amount of the  consideration
received  upon  the  issue  thereof  being  determined  under  Paragraph  (e) of
Subsection   3.3.  The  Company  shall  not  effect  any  such   reorganization,
reclassification  of  capital  stock,  consolidation,   merger,  sale  or  other
disposition  unless,  upon or prior to the consummation  thereof,  the successor
corporation shall assume by written  instrument the obligation to deliver to the
Registered Holder such shares of stock or other securities,  cash or property as
such  Registered  Holder shall be entitled to purchase in  accordance  with this
Warrant's provisions.

                                      -10-
<PAGE>
                                    SECTION 6
                              NOTICE OF ADJUSTMENT

         Immediately  upon any  adjustment  of the Exercise  Price,  the Company
shall  send  written  notice  thereof to all  Registered  Holders,  stating  the
adjusted  Exercise  Price and the number of Stock  purchasable  upon exercise of
this Warrant and setting  forth in reasonable  detail the method of  calculation
for such  adjustment.  When possible,  such notice shall be given in advance and
included as part of any notice required to be given pursuant to Section 7 below.

                                    SECTION 7
                         PRIOR NOTICE OF CERTAIN EVENTS

         If at any time:

                    (a) The Company shall pay any dividend payable in stock upon
its Common Stock or make any  distribution  (other than cash  dividends)  to the
holders of its Common Stock of record;

                    (b) The Company shall offer for subscription pro rata to the
holders of its  Common  Stock of record  any  additional  shares of stock of any
class or any other rights;

                    (c) There shall be any reorganization or reclassification of
the capital  stock of the Company,  any  consolidation  or merger of the Company
with another corporation, or a sale or other disposition of all or substantially
all its assets;

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

                    (e)  The  Company  shall  file  any  registration  statement
pursuant to the Securities Act of 1933, as amended (the "Act"),

then,  in each such case,  and to the extent that the Company can  reasonably do
so, the  Company  shall give prior  written  notice of the date on which (i) the
books of the  Company  shall  close or a record  shall be taken  for such  stock
dividend,   distribution,   subscription   or   other   rights   or  (ii)   such
reorganization,   reclassification,   consolidation,   merger,   sale  or  other
disposition,  dissolution,  liquidation,  winding up or filing of a registration
statement shall take place, as the case may be. A copy of each such notice shall
be sent  simultaneously  to each transfer  agent of the Company's  Common Stock.
Such notice  shall also specify the date as of which the holders of Common Stock
of  record  shall  participate  in said  dividend,  distribution,  subscription,
registration or other rights or shall be entitled to exchange their Common Stock
for  securities  or  other  property  deliverable  upon  such  reclassification,
consolidation,  merger,  sale or other  disposition,  dissolution,  liquidation,
winding up or filing,

                                      -11-
<PAGE>
as the case may be, and in any case  contemplated by Paragraph (d) of Subsection
3.3,  shall  include  the  Company's  calculation  of  the  Fair  Value  of  the
consideration whose Fair Value requires determination. Such written notice shall
be given at least thirty (30) days prior to the record date or the  effective or
filing date,  whichever is earlier,  of the subject  action or other event.  The
failure by the Company to give any such notice shall not serve to invalidate any
action otherwise validly taken by the Company.

                                    SECTION 8
                           RESERVATION OF COMMON STOCK

         The Company shall at all times  thereafter  reserve and keep  available
for issuance upon the exercise of the Warrants such number of its authorized but
unissued  shares of Common Stock as will be sufficient to permit the exercise in
full of all outstanding  Warrants,  and upon such issuance such shares of Common
Stock will be validly issued, fully paid and nonassessable.

                                    SECTION 9
                       NO SHAREHOLDER RIGHTS OR OBLIGATION

         This  Warrant  shall not  entitle the  Registered  Holder to any voting
rights or other rights as a  shareholder  of the  Company.  No provision of this
Warrant,  in the  absence  of  affirmative  action by the  Registered  Holder to
purchase  Stock,  and no enumeration in this Warrant of the rights or privileges
of the Registered  Holder,  shall give rise to any obligation of such Registered
Holder for the payment of the  Exercise  Price of Stock  acquirable  by exercise
hereof (in absence of such actual exercise) or as a shareholder of the Company.

                                   SECTION 10
                    EXCHANGEABLE FOR DIFFERENT DENOMINATIONS

         This  Warrant  is  exchangeable,  upon  the  surrender  hereof  by  the
Registered  Holder at the principal  office of the Company,  for new Warrants of
like tenor  representing in the aggregate the purchase rights hereunder,  as set
forth on the front page  hereof,  and each of such new Warrants  will  represent
such portion of such rights as is  designated  by the  Registered  Holder at the
time of such  surrender.  The date the Company  initially  issued this  Warrant,
which is set forth on the front page hereof,  shall be deemed to be the "Date of
Issuance" of this Warrant and any Warrant  exchanged or  substituted  therefore,
regardless  of the dates on which new Warrants  representing  the  unexpired and
unexercised rights formerly represented by this Warrant are issued.


                                      -12-
<PAGE>
                                   SECTION 11
                                 TRANSFERABILITY

         Subject only to the transfer conditions referred to in this Section 11,
this Warrant and all rights  hereunder  are  transferable,  in whole or in part,
without  restriction and without charge to the Registered Holder, upon surrender
of this Warrant with a properly executed  Assignment  (substantially in the form
of Exhibit II hereto) at the principal  office of the Company.  This Warrant and
the Stock issued upon exercise  hereof may not be offered,  sold or  transferred
except in compliance with the Act and any applicable  state securities laws, and
then only  against  receipt of an  agreement of the Person to whom such offer or
sale is made to comply with the  provisions  of this  Section 11 with respect to
any  resale or other  disposition  of such  securities;  provided,  that no such
agreement shall be required from any Person purchasing this Warrant or any Stock
pursuant to a  registration  statement  effective  under the Act. The Registered
Holder  agrees  that,  prior to the  disposition  of any Stock  purchased on the
exercise  hereof under  circumstances  that might require  registration  of such
Stock under the Act,  or any  similar  statute  then in effect,  the  Registered
Holder shall give written notice to the Company,  expressing its intention as to
such  disposition.  Within three (3) business days after  receiving such notice,
the Company shall present a copy thereof to its securities  counsel.  If, in the
opinion of such counsel,  which shall be rendered  within five (5) business days
after  receiving such notice,  or in the opinion of the Registered  Holder's own
counsel  (which  shall be in form and from such  counsel as shall be  reasonably
satisfactory  to  the  Company),  the  proposed  disposition  does  not  require
registration of such Stock under the Act, or any similar statute then in effect,
the  Company  shall,  within  two (2)  business  days of the  rendering  of such
opinion, notify the Registered Holder of such opinion,  whereupon the Registered
Holder shall be entitled to dispose of such Stock in  accordance  with the terms
of the notice  delivered  by the  Registered  Holder to the  Company.  The above
agreement by the  Registered  Holder shall not be deemed to limit or restrict in
any respect the exercise of rights set forth in Section 12 hereof.

                                   SECTION 12
                               REGISTRATION RIGHTS

         12.1 "Piggyback" Rights. If at any time during the Exercise Period, the
Company  shall  prepare and file a  registration  statement  under the Act, with
respect  to a public  offering  of equity  or debt  securities  of the  Company,
whether by the Company or by other  Persons,  then the Company  shall include in
any  such  registration  statement  or  any  post-effective  amendment  to  such
registration  statement,  such information as may be required to permit a public
offering of Stock held by any Registered Holders  requesting  inclusion of their
Stock; provided that where such offering is to be an underwritten  offering, and
in the opinion of the Company's managing  underwriter the inclusion of the Stock
requested to be registered, when added to the other securities being registered,
would exceed the maximum amount of the company's securities that can be marketed
without otherwise  materially and adversely affecting the entire offering,  then
the Company may exclude from such offering a portion of

                                      -13-
<PAGE>
the Stock requested to be so registered,  so that the total number of securities
to be registered is within the maximum  number of shares that, in the opinion of
the managing  underwriter,  may be marketed  without  otherwise  materially  and
adversely  affecting  the entire  offering.  In the event  there are  previously
issued securities other than the Stock that are proposed to be registered in the
registration  pursuant to  registration  rights that were  granted  prior to the
rights granted  hereunder (the "Prior  Rights"),  then, the rights granted under
this  Subsection  12.2 shall be subject to all such Prior Rights,  and the Stock
may be  excluded  from such  registration  to the extent  that the Prior  Rights
require;  provided,  however,  that the  entire  amount of any other  securities
without  Prior  Rights  shall be  excluded  from such  registration  before  the
exclusion of any portion of the Stock for which  registration was requested by a
Registered  Holder.  Each  Registered  Holder of  Warrant  Securities  for whose
account any Stock may be included in a post-effective  amendment or registration
statement shall have the unrestricted  right to withhold Stock from inclusion in
the underwritten offering, without regard to whether registration was requested.
The Company shall bear all fees and expenses  incurred by it in connection  with
the preparation and filing of such post-effective  amendment or new registration
statement.  In the event of such a  proposed  registration,  the  Company  shall
furnish the then  Registered  Holders of Warrant  Securities  with not less than
thirty (30) days'  written  notice prior to the proposed  date of filing of such
post-effective  amendment  or new  registration  statement.  Such  notice  shall
continue to be given by the Company to Registered Holders of Warrant Securities,
with respect to subsequent registration statements or post-effective  amendments
filed by the  Company,  until such time as all of the Stock may be sold  without
restriction  under the Act and applicable state securities laws and regulations,
and the Registered Holders have received an opinion from counsel for the Company
(in  such  form and  from  counsel  reasonably  satisfactory  to the  Registered
Holders)  that all of the Stock is so saleable  under SEC Rule 144 or  otherwise
within the immediate  90-day period  commencing on the date a sale is requested.
The Registered  Holders of Warrant Securities shall exercise the rights provided
for in this  Subsection  12.2 by giving  written  notice to the Company,  within
twenty (20) days of receipt of the  Company's  notice of its intention to file a
post-effective amendment or new registration statement.

         12.2 Use of Prospectus.  The Registered Holder,  upon receipt of notice
from the Company of the occurrence of an event which  requires a  post-effective
amendment to a  registration  statement  or an amendment or a supplement  to the
prospectus  included therein,  shall promptly  discontinue the sale of his Stock
until it has received  copies of a supplemented  or amended  prospectus from the
Company,  and  until  such  receipt,  the  running  of  any  minimum  period  of
effectiveness required by Subsection 12.1 shall be tolled.

         12.3  Failure  to Supply  Information.  Registered  Holders  requesting
inclusion of Stock in any registration  statement filed by the Company shall, at
such  Holder's cost and expense,  cooperate  fully and promptly with the Company
and its counsel in supplying such information  concerning the Registered  Holder
and such Holder's plan of  distribution  as may reasonably be required to effect
such registration. Any Registered Holder who fails to so cooperate and to timely
supply information to the Company that is required to obtain


                                      -14-
<PAGE>
effectiveness  of a registration  statement shall have such Registered  Holder's
Stock excluded from the registration  statement without liability on the part of
the Company for any such failure to include the such  Registered  Holder's Stock
in the Registration Statement.

         12.4 Withdrawal of Stock from  Registration.  Any Registered Holder who
withdraws such Holder's Stock from any registration statement commenced pursuant
to Subsection  12.1 hereof,  at such Holder's  request,  shall be deemed to have
received full benefit of a completed registration under Subsection 12.1 hereof.

         12.5  Exclusion  of Stock from Certain  Registrations.  Notwithstanding
anything to the contrary  contained herein,  the registration  rights granted to
the Holders  hereunder shall not be available to allow inclusion of the Stock in
the Registration  Statement first filed by the Company with the Commission as of
May 14, 1998 (SEC File No. 333-52625) or any  post-effective  amendment thereto,
unless the Holder has first obtained the written  consent of all persons holding
Series A  Preferred  Stock to  include  the Stock in such  registration.  Holder
understands  and agrees that the Company has no  obligation  to assist Holder in
obtaining such consent and that any holder of such Series A Preferred  Stock may
refuse such consent in such holder's sole discretion.

                                   SECTION 13
                                 INDEMNIFICATION

                    (a) By the Company. The Company shall indemnify, to the full
extent permitted by law, the Registered  Holder,  its directors and officers (if
applicable) and each person,  if any, who controls the Registered  Holder within
the  meaning of Section 15 of the Act,  against  any  losses,  claims,  damages,
liabilities and expenses  resulting from any untrue or alleged untrue  statement
of a material  fact  contained  in any  registration  statement,  prospectus  or
preliminary  prospectus  or any omission or alleged  omission to state therein a
material  fact  necessary  to make the  statements  therein  (in the case of the
prospectus or any preliminary  prospectus,  in light of the circumstances  under
which they were made) not  misleading,  except insofar as the same are caused by
or contained in any information with respect to the Registered  Holder furnished
in writing to the Company by the Registered Holder expressly for use therein.

                    (b)  By  the  Registered  Holder.  In  connection  with  any
registration  statement in which the  Registered  Holder is  participating,  the
Registered  Holder  shall  indemnify,  to the full extent  permitted by law, the
Company,  its  directors  and  officers and each person who controls the Company
(within  the  meaning of  Section 15 of the Act)  against  any  losses,  claims,
damages,  liabilities  and expenses  resulting from any untrue or alleged untrue
statement of a material fact contained in any registration statement, prospectus
or preliminary prospectus or any omission or alleged omission to state therein a
material  fact  necessary  to make the  statements  therein  (in the case of the
prospectus or any preliminary  prospectus,  in light of the circumstances  under
which they were made) not misleading, but


                                      -15-
<PAGE>
only  insofar as the same are caused by or  contained  in any  information  with
respect to the  Registered  Holder  furnished  in writing to the  Company by the
Registered Holder expressly for use therein.

                    (c) Indemnification  Procedures.  Any person who is entitled
to indemnification under this Section 13 shall (i) give prompt written notice to
the   indemnifying   party  of  any  claim  with   respect  to  which  it  seeks
indemnification and (ii) permit such indemnifying party to assume the defense of
such  claim with  counsel  reasonably  satisfactory  to the  indemnified  party.
Whether  or  not  such  defense  is  assumed  by  the  indemnifying  party,  the
indemnifying party shall not be subject to any liability for any settlement made
without  its  consent.  No  indemnifying  party  shall  consent  to entry of any
judgment 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 of such  claim or  litigation.  An
indemnifying  party who is not entitled to, or elects not to, assume the defense
of a claim shall not be  obligated to pay the fees and expenses of more than one
counsel for all parties  indemnified by such indemnifying  party with respect to
such  claim,  unless  in the  reasonable  judgment  of any  indemnified  party a
conflict  of  interest  may  exist  between  such  indemnified  party  and other
indemnified  parties with respect to such claim, in which event the indemnifying
party shall be obligated to pay the fees and expenses of such additional counsel
or counsels.

                    (d)  Contribution.  If for  any  reason  an  indemnification
provision of this Section 13 is held by a court of competent  jurisdiction to be
unavailable to an  indemnified  party with respect to any loss,  claim,  damage,
liability or expense referred to therein,  then the indemnifying  party, in lieu
of indemnifying  each  indemnified  party  thereunder,  shall  contribute to the
amount  paid or payable by the  indemnified  party as a result of any such loss,
claim,  damage,  liability or expense in such  proportion  as is  applicable  to
reflect not only the relative benefits received by the indemnified party and the
indemnifying  party,  but also the relative fault of the  indemnified  party and
indemnifying party, as well as any other relevant equitable considerations.  The
relative fault of the indemnifying  party and of the indemnified  party shall be
determined by reference  to, among other  things,  whether any untrue or alleged
untrue  statement of a material fact or omission to state  material fact relates
to information  supplied by the indemnifying  party or by the indemnified  party
and  the  parties'  relative  intent,  knowledge,   access  to  information  and
opportunity to correct or prevent such statement or omission.

                    (e) Actions by  Registered  Holder.  The  Registered  Holder
shall,   at  his  cost  and   expense,   complete,   execute   and  deliver  all
questionnaires,  powers  of  attorney,  undertakings  and  other  documents  and
instruments,  and  take  all  such  other  actions,  as are  from  time  to time
reasonably requested by the Company.

                    (f) Survival.  The rights and  obligations set forth in this
Section 13 shall survive the exercise and surrender of this Warrant.


                                      -16-
<PAGE>
                                   SECTION 14
                                  MISCELLANEOUS

         14.1 Original  Issue Taxes.  The Company  shall pay all United  States,
state and  local  (but not  foreign)  original  issue  taxes,  if any,  upon the
issuance of this Warrant or the Stock deliverable upon exercise hereof.

         14.2 Amendment and Waiver.  Except as otherwise  provided  herein,  the
provisions of the Warrants may be amended,  and the Company make take any action
herein  prohibited or omit to perform any act herein required to be performed by
it, only if the  Company has  obtained  the  written  consent of the  Registered
Holders of  Warrants  representing  at least  fifty  percent  (50%) of the Stock
obtainable  upon the  exercise of the Warrants  outstanding  at the time of such
consent.

         14.3 Notices.  Any notices  required to be sent to a Registered  Holder
shall be delivered to the address of such  Registered  Holder shown on the books
of the Company.  All notices  referred to herein shall be delivered in person or
sent by registered or certified mail,  postage  prepaid,  and shall be deemed to
have been  given  when so  delivered  in person,  or on the third  business  day
following  the date so sent by mail.  Whether or not  Purchaser  or an affiliate
thereof  shall then be a  Registered  Holder,  a copy of any notice  sent to any
Registered  Holder  shall  be  sent  to in the  manner  provided  above,  at the
following addresses:

                           ===========================
                           ===========================

                           Attn:  ____________________

         Any notices  required  to be sent to the  Company  shall be sent by the
same means as notices to be sent to the  Registered  Holders,  at the  following
address:

                           U.S. Wireless Data, Inc.
                           2200 Powell Street
                           Suite 800
                           Emeryville, California  94608
                           Attention:  Chief Financial Officer

         14.4 Attorney's Fees; Costs. In any litigation  between the Company and
Registered  Holders  or  former  Registered   Holders,   including  actions  for
enforcement or interpretation, arising out of this Warrant, the prevailing party
shall be entitled to recover reasonable attorney's fees, costs and expenses.


                                      -17-
<PAGE>
         14.5 Descriptive  Headings;  Governing Law. The descriptive headings of
the  sections,  subsections  and  paragraphs  of this  Warrant are  inserted for
convenience only and do not constitute a part of this Warrant. The construction,
validity and interpretation of this Warrant shall be governed by the laws of the
State of Colorado,  without  giving  effect to choice of law or conflict of laws
principals, and the venue shall be Denver, Colorado.

         IN WITNESS WHEREOF,  the Company has caused this Warrant to be executed
and attested by its duly authorized officers under its corporate seal.

                                           U.S. WIRELESS DATA, INC.,
                                           a Colorado corporation


                                           By: ____________________________   
                                               Roger L. Peirce
                                               Chief Executive Officer


[Corporate Seal]

Attest:


_______________________________
Robert E. Robichaud
Corporate Secretary

                                      -18-
<PAGE>

                                    EXHIBIT I

                               EXERCISE AGREEMENT

To:                                                   Dated:

         THE UNDERSIGNED Registered Holder, pursuant to the provisions set forth
by the within  Warrant,  hereby  subscribes for and purchases  _________________
shares of Stock covered by such Warrant and herewith elects to make:

     ( ) a Cashless Exercise at the Exercise Price provided by such Warrant.

     ( ) full cash payment of $  ______________  for such shares at the Exercise
Price provided by such Warrant.

                                   __________________________________
                                   (Signature)

                                   __________________________________
                                   (Print or type name)

                                   __________________________________

                                   __________________________________
                                    (Address)


         NOTICE:  The signature on this Exercise  Agreement must correspond with
the name as written upon the face of the within Warrant,  or upon the Assignment
thereof if applicable, in every particular, without alteration,  enlargement, or
any change whatsoever,  and must be Medallion guaranteed by a bank (other than a
savings  bank),  or  by  a  firm  having  membership  on a  registered  national
securities exchange.

                               SIGNATURE GUARANTEE

Authorized Signature:__________________________________________________

Name of Bank or Firm: _________________________________________________  

Dated: ________________________________________________________________   


<PAGE>
                                   EXHIBIT II

                                   ASSIGNMENT

     FOR VALUE RECEIVED,  _______________________  , the undersigned  Registered
Holder hereby sells,  assigns,  and transfers all the rights of the  undersigned
under  the  within  Warrant  No.  ___________  with  respect  to the  number  of
Securities covered thereby set forth below, unto the Assignee  identified below,
and does hereby irrevocably constitute and appoint  ____________________________
____________________________________________________  to effect such transfer of
rights on the books of the Company, with full power of substitution:


                                                No. of Shares
Name of Assignee        Address of Assignee       of Stock      No. of Warrants
----------------        -------------------       --------      ---------------





Dated:                                      ___________________________________
                                           (Signature of Registered Holder)

                                            ___________________________________
                                           (Print or type name)


         NOTICE:  The signature on this Assignment must correspond with the name
as written upon the face of the within  Warrant,  in every  particular,  without
alteration,  enlargement,  or any  change  whatsoever,  and  must  be  Medallion
guaranteed by a bank (other than a savings bank), or by a firm having membership
on a registered national securities.


                               SIGNATURE GUARANTEE


Authorized Signature:__________________________________________________

Name of Bank or Firm: _________________________________________________   

Dated: ________________________________________________________________