U.S. WIRELESS DATA, INC.

                      NONQUALIFIED STOCK OPTION CERTIFICATE

         U.S. Wireless Data, Inc., a Colorado corporation ("Company"),  for good
and valuable consideration, including the incentive to the Optionee to remain as
an employee of the Company as a result of ownership  or  increased  ownership of
the  Company's  no par value  common  stock  ("Common  Stock"),  the receipt and
sufficiency of which consideration hereby is acknowledged, irrevocably grants to
the Optionee the option ("Option") to purchase the following number of shares of
Common Stock:

               Optionee                            Number of Shares
               --------                            ----------------

            Evon A. Kelly                               600,000


The  effective  date of this grant is August 4, 1997  ("Date of  Grant")  and is
subject to the following terms and conditions:

         1. Exercise Price. The purchase price ("Exercise  Price") for shares of
Common Stock  purchased  pursuant to this Option shall be One Dollar ($1.00) per
share,  which  shall be paid in full in cash at the time of  exercise,  provided
that the Board of  Directors  of the Company may in its sole  discretion  permit
payment to be made with shares of the Company's  Common Stock owned by Optionee.
The Exercise Price represents the closing price of the Company's Common Stock as
of the date this Option is granted.  Optionee  shall have no rights with respect
to dividends or have any other  rights as a  shareholder  with respect to shares
subject to this Option until  Optionee has given written  notice of the exercise
of the Option and has paid in full for such shares.

         2. Time of  Exercise.  This Option may be  exercised  as to ten percent
(10%) of the total  shares  covered by this Option on the Date of Grant,  and 3%
per month  thereafter,  until  fully  vested,  so long as the  Optionee  remains
employed by the Company.  This Option shall  terminate 10 years from the Date of
Grant of this Option,  or three months after the  termination of employment with
the Company,  whichever  is shorter.  The period of time during which the Option
may be exercised is referred to herein as the "Option Period."

         3. Number of Shares. This Option shall be exercised only for 100 shares
of Common Stock or a multiple thereof or for the full number of shares for which
the Option is then exercisable.

         4. Death of Optionee.  If Optionee dies during Optionee's employment by
the  Company,  this  Option  shall  be  exercisable  only  as  to  that  portion
exercisable as of the date of death and within one year after  Optionee's  death
or the last day of the Option  Period,  whichever  is earlier,  by the  personal
representative or administrator of Optionee's  estate, or by any trustee,  heir,
legatee or beneficiary to whom Optionee's rights under this Option shall


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pass by will or the laws of descent and distribution to the extent that Optionee
was entitled to exercise this Option at the time of Optionee's death.

         5.  Retirement of Optionee.  If Optionee's  employment with the Company
terminates by reason of retirement,  the Option shall be exercisable only within
three months after the date of such  retirement  but not later than the last day
of the  Option  Period  and then  only to the  extent to which  the  Option  was
exercisable  at the  time of  such  termination  of  employment  by  retirement.
However,  if Optionee dies within three months after  termination by retirement,
the Option,  to the extent it was  exercisable at the time of Optionee's  death,
shall thereafter be exercisable for one year after the date of Optionee's death,
but not later than the last day of the Option Period.

         6. Disability of Optionee.  If Optionee becomes permanently and totally
disabled,  and at the time of such  disability  Optionee is entitled to exercise
one or more  installments  under this Option,  Optionee  shall have the right to
exercise this Option  within one year after such  disability  provided  Optionee
exercises  this Option  within the Option  Period and then only to the extent to
which this Option was exercisable at the time of such  disability.  For purposes
of this Section 6 an Optionee shall be considered to be totally and  permanently
disabled if a qualified medical  physician  approved by the Company certifies to
the Company that such Optionee is unable to be gainfully employed by the Company
by reason of a diagnosed and  determinable  physical or mental  impairment which
can be expected to result in death or has lasted and can be expected to last for
a continuous period of not less than 12 months.

         7.  Termination of Employment.  If Optionee's  employment is terminated
for any reason other than death, disability or retirement,  any option which was
exercisable at the time of termination  shall  terminate  three months after the
date upon which Optionee's employment terminates.

         8.  Nontransferability of Option. This Option may not be transferred by
Optionee otherwise than by will or the laws of descent and distribution.  During
Optionee's lifetime, this Option shall be exercisable only by Optionee.

         9.  Leave of  Absence.  For  purposes  of this  Option,  (i) a leave of
absence,  duly  authorized  in writing by the Company,  for military  service or
sickness,  or for any other  purpose  approved by the Company,  if the period of
such leave does not exceed 90 days,  and (ii) a leave of absence in excess of 90
days, duly authorized in writing by the Company,  provided  Optionee's  right to
reemployment is guaranteed either by statute or by contract, shall not be deemed
a termination of employment.

         10. Changes in Capital;  Certain  Reorganizations.  If the  outstanding
Common Stock of the Company which is subject to this Option shall at any time be
changed or exchanged by declaration of a stock dividend,  split-up,  subdivision
or  combination  of shares,  recapitalization,  merger,  consolidation  or other
corporate reorganization in which the Company is the surviving corporation,  the
number of and kind of shares subject to the Option and the Option Price shall be
appropriately and equitably adjusted so as to maintain the proportionate  number
of  shares  without  changing  the  aggregate  option  price.  In the event of a
dissolution or liquidation of the Company, or a merger,  consolidation,  sale of
all or substantially all of its

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assets,  or other  corporate  reorganization  in which  the  Company  is not the
surviving corporation,  or in which the Company is the surviving corporation but
holders of Common Stock receive securities of another  corporation,  this Option
shall  terminate  as  of  the  effective  date  of  such  event,  provided  that
immediately prior to such event,  Optionee shall have the right to exercise this
Option as to all shares  underlying  this Option,  irrespective of the number of
Options actually vested at the time.

         11. Manner of Exercise.  Subject to the terms and conditions  contained
herein  this  Option may be  exercised  in whole or in part at any time and from
time to time within the Option  Period by the delivery of written  notice to any
officer or director  of the  Company  other than  Optionee,  together  with full
payment,  in cash or with the Company's  Common Stock having a fair market value
equal to the aggregate  exercise price for the number of shares  purchased.  The
notice (i) shall state the election to exercise the Option, (ii) shall state the
number of shares in respect to which the Option is being exercised,  (iii) shall
state Optionee's  address,  (iv) shall state Optionee's  social security number,
(v) shall contain such  representations  and  agreements  concerning  Optionee's
investment  intent  with  respect  to such  shares of  Common  Stock as shall be
satisfactory to the Company's counsel, and (vi) shall be signed by Optionee.  As
a further  condition  to the  exercise of this  Option,  the Company may require
Optionee  to make any  representation  and  warranty  to the  Company  as may be
required by any applicable law or regulation.

         12. Amendment and Administration. The Board of Directors shall have the
authority  to  interpret  the Plan this  Option,  and  generally  to conduct and
administer  the  exercise  of this  Option  and to make  all  determinations  in
connection herewith which may be necessary or advisable, and all such actions of
the Board  shall be final and  conclusive  for all  purposes  and  binding  upon
Optionee.

         13.  Miscellaneous.  This  Option  shall inure to the benefit of and be
binding upon each successor of the Company. All obligations imposed upon and all
rights granted to the Optionee and all rights reserved by the Company under this
Option shall be binding  upon and inure to the benefit of  Optionee,  Optionee's
heirs,  personal  representatives,  administrators  and  successors.  Unless the
context  requires  otherwise,  words  denoting  the singular may be construed as
denoting  the plural,  and words of the plural may be  construed as denoting the
singular and words of one gender my be  construed as denoting  such other gender
as is appropriate.

<PAGE>
         Date of Grant:  August 4, 1997


U.S. WIRELESS DATA, INC.                         Accepted by Optionee:
a Colorado corporation

By  /s/ Rod L. Stambaugh                        /s/ Evon A. Kelly   
    --------------------                        -----------------  
    Rod L. Stambaugh                                Evon A. Kelly
    President



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