EXHIBIT 4.1


THIS NOTE AND THE SECURITIES ISSUABLE UPON CONVERSION OF THIS NOTE HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED,  OR QUALIFIED UNDER ANY
STATE SECURITIES LAW, AND MAY NOT BE SOLD,  TRANSFERRED ASSIGNED OR HYPOTHECATED
UNLESS THERE IS AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH ACT COVERING THIS
NOTE AND/OR SUCH  SECURITIES,  OR THE HOLDER  RECEIVES AN OPINION OF COUNSEL FOR
THE HOLDER OF THE NOTE AND/OR SUCH  SECURITIES  SATISFACTORY  TO THE CORPORATION
STATING THAT SUCH SALE, TRANSFER, ASSIGNMENT OR HYPOTHECATION IS EXEMPT FROM THE
REGISTRATION  AND  PROSPECTUS   DELIVERY   REQUIREMENTS  OF  SUCH  ACT  AND  THE
QUALIFICATION REQUIREMENTS UNDER STATE LAW.



                            U.S. WIRELESS DATA, INC.

                        10%, UNSECURED and NONASSIGNABLE,

                    CONVERTIBLE SUBORDINATED PROMISSORY NOTE

                                DUE JUNE 2, 1998



$150,000                                                            June 3, 1997

1)   Obligation.  FOR VALUE  RECEIVED,  U.S.  Wireless  Data,  Inc,  a  Colorado
     corporation (hereinafter called the "Corporation"),  hereby promises to pay
     entrenet Group LLC  (hereinafter  called the "Holder") the principal sum of
     One Hundred Fifty  Thousand  Dollars  ($150,000)  payable in one payment of
     principal  and all  accrued  interest  due on June 2,  1998  (the  "Payment
     Date"),  unless earlier converted  pursuant to the terms of this Debenture.
     Interest  shall accrue on this  Debenture at the rate of ten percent  (10%)
     per annum (based on a 360-day year,  30-day month) until payment in full of
     principal.

2)   Medium of Payment. The principal and interest on this promissory note (this
     "Note") are payable in lawful money of the United  States of America at the
     Holder's  address set forth below,  or at such other  address as the Holder
     hereof may from time to time designate to the Corporation in writing.

3)   Prepayment. The Corporation may not prepay this Note in whole or in part at
     any time prior to due date of this Note.
 
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                                 Initial:  entrenet /s/ JB     Company /s/ EK
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4)   Subordination.

         a. Senior  Indebtedness.  The payment of principal and interest on this
     Note  is   subordinated  to  the  prior  payment  in  full  of  all  Senior
     Indebtedness  of the  Corporation,  whether  outstanding  on  this  date or
     thereafter. Senior Indebtedness is defined as the principal of, and premium
     and interest on,  indebtedness  of the Corporation for money borrowed from,
     or the  payment  of  which  has  been  guaranteed  to,  persons,  firms  or
     corporations  which  engage  in  lending  money,  including,   but  without
     limitation,   banks,   trust  and  charitable   trusts,   pension   trusts,
     governmental lenders and other investing organizations,  evidenced by notes
     or similar obligations.

         b.  Accelerated  Maturity.  If this Note is  declared  due and  payable
     before  its  express  maturity  because  of the  occurrence  of an event of
     default as defined in this Note,  the Holder  will be  entitled  to payment
     only  after  there is first  paid in full on the  then  outstanding  Senior
     Indebtedness   all   principal   and  interest  then  due  and  payable  by
     acceleration  or  otherwise,  or after  payment  shall be provided for in a
     manner satisfactory to the holders of such Senior Indebtedness.

         c. No  Reduction  in  Corporation's  Obligations.  No present or future
     holder of Senior  Indebtedness  will be prejudiced by the Holder's right to
     enforce  this  Note  by any  act or  failure  to  act  on the  part  of the
     Corporation. The provisions of this Section 4 are solely for the purpose of
     defining the relative  rights of the holders of Senior  Indebtedness on the
     one hand and the Holder of this Note on the other hand, and nothing in this
     Note  will  impair  as  between  the  Corporation   and  the  Holder,   the
     Corporation's obligation to pay to the Holder the principal and interest in
     accordance  with its terms,  nor will  anything  in this Note  prevent  the
     Holder from exercising all remedies  otherwise  permitted by applicable law
     upon  default  hereunder  subject  only to the rights,  if any,  under this
     Section of holders of Senior  Indebtedness  to receive  cash,  property  or
     securities otherwise payable or deliverable to the Holder.

5)   Conversion.

         a. Timing.  This Note is convertible into fully paid and  nonassessable
     shares of the  Corporation's  Common Stock, at the option of the Holder, at
     any time and from time to time  thereafter  in whole or in part  during the
     term of this Note. The Corporation  agrees to reserve sufficient shares for
     issuance  during the remaining  term of this Note so as to be able to honor
     the  exercise  of the  conversion  privilege,  subject to the  Corporations
     increase  in  Common  Stock  to be  presented  at  the  next  Shareholders'
     Meeting..

         b.  Conversion   Price.   The  Note  shall  be  convertible   into  the
     Corporation's Common Stock at a price of fifty cents ($0.50) per share. The
     Conversion  is payable by the  cancellation  of  principal  and any accrued
     interest on this Note.

          c.  Notice  of  Conversion  and  Rights.  In  order  to  exercise  the
     conversion  privilege  granted to the Holder of this Note,  the Holder will
     surrender this Note to the
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                                 Initial:  entrenet /s/ JB     Company /s/ EK
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     Corporation with duly executed Notice of Conversion  specifying the portion
     of the principal  amount and any accrued and unpaid interest of the Note to
     be converted. If the Common Stock into which this Note is convertible is to
     be issued in a name or names other than that of the  Holder,  the Notice of
     Conversion must bear or be accompanied by proper  endorsement or assignment
     of this Note. The Common Stock issued upon the conversion of this Note will
     not be entitled to any dividend  declared upon such stock prior to the date
     of the receipt by the  Corporation of such Notice of  Conversion,  and upon
     such  conversion,  the Holder will not be entitled to any  interest on this
     Note not due and payable at or prior to the date such Notice of  Conversion
     is received by the Corporation.

         d. Surrender and Cancellation of Note. This Note will be deemed to have
     been  surrendered  for conversion and converted at the close of business on
     the date on which it is received by the  Corporation or a designated  agent
     of the Corporation with the duly executed Notice of Conversion, and on such
     receipt,  the Corporation  will promptly issue and deliver to the person or
     persons  entitled  a  certificate  or  certificates  of  its  Common  Stock
     evidencing  the  number  of  shares  into  which  this  Note will have been
     converted,  together  with a new  Note  representing  the  unconverted  and
     unredeemed portion, if any, of the Note so converted. The new Note shall be
     payable to the Holder and dated as of the date to which  interest  has been
     paid on the converted  Note.  Such new Note shall otherwise be identical to
     the converted Note. The Corporation  will then cancel this Note. Only whole
     shares of the Corporation's  Common Stock will be issued on any conversion.
     In the event that  Holder of this Note is  entitled to a faction of a share
     of Common  Stock,  the  Corporation  shall instead pay such holder the cash
     equivalent of that fractional  share,  computed by multiplying the fraction
     by the applicable Conversion Price.

6)   The  Corporation's  Obligation to Register.  If the Corporation at any time
     proposes to initiate a registration of its securities  under the Securities
     Act of 1933, as amended (the  "Securities  Act") and thereafter to register
     any of its  securities  under the Securities Act (other than a registration
     effected  solely to implement an employee  benefit plan, a  transaction  to
     which Rule 145 of the Commission is applicable or any other form or type of
     registration in which Registrable Securities cannot be included pursuant to
     Commission rule or practice), it will give written notice to Holder of this
     Note of its intention to do so. If such registration is proposed to be on a
     form which permits inclusion of the Stock underlying the conversion of this
     Note,  upon the  written  request  from any  Holder  within  20 days  after
     transmittal  by  the  Corporation  to  the  Holder  of  such  notice,   the
     Corporation will, subject to the limits contained in this Section,  use its
     best efforts to cause all such Stock underlying the conversion of this Note
     to be registered  under the Securities Act and qualified for sale under any
     relevant  state blue sky law,  all to the extent  requisite  to permit such
     sale  or  other   disposition   by  Holder  of  the  Stock  so  registered.
     Notwithstanding  any other  provision of this Section,  if the  underwriter
     managing  such  registration  notifies the Holder in writing that market or
     economic  conditions limit the amount of securities which may reasonably be
     expected to be sold,  Holder will at a minimum be allowed to register their
     Stock pro rata based on the ratio of the total number of shares of Stock to
     be offered for sale by the Corporation to the total shares outstanding just

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                                  Initial:  entrenet /s/ JB     Company /s/ EK
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    prior to the  offering.  The  Corporation  and  entrenet  will enter into a
     customary   registration   agreement   setting  forth  the  terms  of  such
     registration  at the time the  Corporation  proposes to register any shares
     for entrenet.

7)   Default.

         a. Events of Default.  Without  notice,  except as  expressly  provided
     herein, the following will be deemed to be events of default:

                  i.  Covenants.  Failure  on the  part  of the  Corporation  to
              observe or perform any of the  covenants or agreements on the part
              of the Corporation contained in this Note after (A) written notice
              of such failure, requiring the Corporation to remedy the same, has
              been given to the Corporation by the Holder,  and (B) such failure
              has continued without remedy for a period of thirty days; or

                  ii.  Receivership.  The  entry of a decree or order of a court
              having  jurisdiction  in  the  matter  for  the  appointment  of a
              receiver  and  such  decree  or  order  has   continued  in  force
              undischarged  or unstayed for a period of one hundred twenty days;
              or

                  iii.Bankruptcy.  The Corporation  institutes proceedings to be
              adjudged  a  voluntary  bankrupt,  or  consents  to the  filing of
              bankruptcy  proceedings  against it, or files a petition or answer
              or consent seeking  reorganization  under the National  Bankruptcy
              Act or any other  similar or  applicable  federal or state law, or
              consents  to the filing of any such  petition,  or consents to the
              appointment of a receiver,  liquidator,  or trustee in bankruptcy,
              or makes a general  assignment  for the benefit of  creditors,  or
              admits in writing its inability to pay its debts generally as they
              become due; or

                  iv. Attachment.  Any judgment,  writ, or warrant of attachment
              or of any  similar  process in an amount in excess of  $100,000 is
              entered or filed  against  the  Corporation  or against any of its
              property  or assets and  remains  unpaid,  unvacated,  unbonded or
              unstayed for a period of 120 days.

         b. Acceleration of Maturity. If any one or more of the foregoing events
     of default occurs, the Holder, by notice in writing to the Corporation, may
     declare  the  principal  of and all  accrued  interest  on this  Note  then
     outstanding  immediately  due and payable without further notice or demand;
     provided,  however, that at any time after such declaration the same may be
     rescinded  and such event of default may be waived by the Holder by written
     notice to the Corporation.

         c. Payment on Acceleration.  Upon any such acceleration of the maturity
     of this Note,  the  Corporation  will  within 90 days pay to the Holder the
     entire  principal  balance  unpaid  on this  Note,  together  with  accrued
     interest thereon to the date of such payment.

         d.  Failure to Pay.  If the  Corporation  fails to make  payment to the
     Holder as provided in the preceding  Subsection  (Payment on Acceleration),
     the Holder will be entitled and  empowered to take such  measures as may be
     appropriate to enforce the  
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                                 Initial:  entrenet /s/ JB     Company /s/ EK
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     Corporation's  obligations  under this Note,  by  judicial  proceedings  or
     otherwise.  If suit is  brought  to  enforce  payment  of  this  Note,  the
     Corporation  promises to pay reasonable  attorneys' fees to be fixed by the
     Court.

8)   Anti-dilution. If the Corporation elects to combine or subdivide its Common
     Stock, the ratio used to determine the number of new shares to be issued in
     exchange  for the  existing  shares will be applied to the number of shares
     into which this Note may be  converted  as provided  in this Note,  and the
     conversion price will be appropriately adjusted.

9)   No Assignment. This Note is unsecured, non-transferable and non-assignable.
     Holder may not sell, assign, pledge, hypothecate or otherwise transfer this
     Note

10)  Notices.  Any  communication  or notices may be  delivered or mailed to the
     offices of the  Corporation  at its principal  place of business and to the
     Holder at the Holder's  address set forth below, or to such other addresses
     as the Corporation, or Holder, may designate in writing from time to time.

11)  Applicable  Law. This Note shall be governed by and construed in accordance
     with the laws of the State of California  applicable  to contracts  between
     California  residents entered into and so be performed  entirely within the
     State of California.

Executed as of June 3,1997



By: /s/  Evon Kelly
    -------------------
         Evon Kelly
         Chief Executive Officer

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                                Initial:  entrenet /s/ JB     Company /s/ EK
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The name and address of the registered Holder of this Note is:

entrenet Group LLC
5213 El Mercado Parkway, Suite D
Santa Rosa, California 95403