PROMISSORY NOTE
                                 ---------------

$100,000
                                                             May 4, 2000
                                                             Passaic, New Jersey

FOR  VALUE  RECEIVED,  the  undersigned  RARE  TELEPHONY,   INC.  (f/k/a  WASHOE
TECHNOLOGY CORPORATION) AND CASH BACK REBATES LD.COM, INC. a Nevada and Delaware
corporation,  respectively  ("Maker"),  promise  to  pay  to  the  order  of VDC
Communications,  Inc.,  a  Delaware  corporation  ("Holder"),  which  term shall
include any subsequent holder of this Note, at 75 Holly Hill Lane, Greenwich, CT
06830 (or at such other place as Holder  shall  designate  in writing) in lawful
money of the  United  States of  America,  the  aggregate  principal  sum of One
Hundred  Thousand  Dollars  ($100,000),  with interest  thereon at the rate (the
"Interest Rate") described below.

         1.   Interest Rate.  The Interest Rate shall be zero percent  (0%)  per
              --------------
              annum.

         2.   Outstanding  Principal Balance. All references to the "Outstanding
              -------------------------------
              Principal  Balance" shall mean the amount of One Hundred  Thousand
              Dollars ($100,000), less any principal repaid.

         3.   Payments.  This note shall be payable in full on October  20, 2000
              ---------
              (the  "Maturity  Date")  when  the  entire  Outstanding  Principal
              Balance,  and any  accrued but unpaid  interest,  shall be due and
              payable.

         4.   Application  of  Payments.  All  payments  on this  Note  shall be
              --------------------------
              applied first to the payment of accrued and unpaid  interest,  and
              then to the reduction of the Outstanding Principal Balance.

         5.   Prepayment  Right.  Maker  shall  have the  right to prepay at any
              ------------------
              time, in whole or in part, the  Outstanding  Principal  Balance of
              this Note, without premium or penalty.

         6.   Accelerated Maturity. Notwithstanding anything in this Note to the
              ---------------------
              contrary  and  irrespective  of  the  Maturity  Date,  the  entire
              Outstanding  Principal  Balance and accrued  interest shall become
              immediately  due and  payable  upon the  earliest  to occur of the
              following (the "Accelerated  Maturity Date"):  (a) the sale of all
              or  substantially  all of the  assets of the  Maker or the  common
              stock of the Maker to a third  party;  or (b) the  issuance of the
              securities of Maker on the public market.

         7.   Modifications. From time to time, without affecting the obligation
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              of Maker to pay the  Outstanding  Principal  Balance or to observe
              the covenants of Maker contained herein, and without giving notice
              to or obtaining the consent of Maker, Holder may, at the option of
              Holder,  extend the time for payment of the Outstanding  Principal
              Balance  or any  part  thereof,  reduce  the  payments  hereunder,

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<PAGE>

              release any person liable hereunder, accept a renewal or extension
              of this Note,  join in any extension or  subordination  agreement,
              release any security given herefor,  take or release security,  or
              agree in writing  with Maker to modify  the  Interest  Rate or any
              other provision of this Note.

         8.   Events  of  Default.  Time  is of the  essence  hereof.  Upon  the
              --------------------
              occurrence  of  any  of  the  following  events  (the  "Events  of
              Default"), payment of the entire Outstanding Principal Balance and
              accrued  interest of this Note shall, at the option of the Holder,
              be accelerated  and shall be immediately  due and payable  without
              notice or demand:

                  (a) Failure of Maker to pay the Outstanding  Principal Balance
                      and accrued  interest in full on the Maturity  Date or the
                      Accelerated Maturity Date; or
                  (b) All or the majority of the value of the assets of Maker is
                      seized or levied upon by writ of attachment,  garnishment,
                      execution  or  otherwise,  and such seizure or levy is not
                      released within thirty (30) calendar days thereafter; or
                  (c) Maker executes a general assignment for the benefit of its
                      creditors,  convenes any meeting of its creditors, becomes
                      insolvent,  admits in writings its insolvency or inability
                      to pay its debts,  or is unable to pay or is generally not
                      paying its debts as they become due; or
                  (d) A receiver,  trustee,  custodian  or agent is appointed to
                      take  possession  of  all or any  substantial  portion  of
                      Maker's assets; or
                  (e) Any case or proceeding is  voluntarily  commenced by Maker
                      under any provision of the federal  Bankruptcy Code or any
                      other   federal   or  state   law   relating   to   debtor
                      rehabilitation,  insolvency,  bankruptcy,  liquidation  or
                      reorganization,   or  any  such  case  or   proceeding  is
                      involuntarily  commenced  against  Maker and not dismissed
                      within thirty (30) calendar days thereafter; or
                  (f) Any representation made by Maker in this Note or in any of
                      the other  documents  delivered in  connection  therewith,
                      shall  have  been  untrue  or  incorrect  in any  material
                      respect when made.

         9.   Default Rate. In the event that Maker fails to pay the Outstanding
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              Principal Balance and all accrued interest in full on the Maturity
              Date  or the  Accelerated  Maturity  Date,  the  amount  past  due
              (including any acceleration of the Outstanding Principal Balance),
              and unpaid  shall  bear  interest  at an annual  rate equal to the
              lesser of (i) fifteen  percent  (15%),  or (ii) the maximum amount
              permitted by law (the "Default  Rate"),  computed from the date on
              which said amount was due and payable until paid.  The charging or
              collecting  of interest at the Default Rate shall not limit any of
              Holder's other rights or remedies under this Note.

         10.  Governing Law. Maker, and each endorser and cosigner of this Note,
              --------------
              acknowledges  and agrees that this Note is made and is intended to
              be  paid  and  performed  in the  State  of  New  Jersey  and  the

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              provisions hereof will be construed in accordance with the laws of
              the State of New Jersey and,  to the extent  that  federal law may
              preempt the  applicability of state laws,  federal law. Maker, and
              each  endorser and  cosigner of this Note further  agree that upon
              the  occurrence of an Event of Default,  this Note may be enforced
              in any court of competent jurisdiction in the State of New Jersey,
              and they do  hereby  submit  to the  jurisdiction  of such  courts
              regardless of their residence.

         11.  Remedies  Cumulative:  Waiver.  The remedies of Holder as provided
              ------------------------------
              herein shall  be  cumulative  and  concurrent,  and may be pursued
              singularly,  successively  or together,  in the sole discretion of
              Holder,  and may  be exercised as often as occasion therefor shall
              arise.  No act of  omission  or  commission  of Holder,  including
              specifically  any  failure  to   exercise  any  right,  remedy  or
              recourse,  shall be deemed to  be a waiver or release of the same;
              such  waiver or release  to  be  affected  only  through a written
              document   executed  by   Holder  and  then  only  to  the  extent
              specifically recited  therein.  Without limiting the generality of
              the preceding sentence,  acceptance by  Holder of any payment with
              knowledge of the occurrence of an Event  of Default by Maker shall
              not be deemed a waiver of such Event of  Default,  and  acceptance
              by Holder of any  payment in an amount  less  than the amount then
              due  hereunder  shall be an  acceptance on  account only and shall
              not in any way  affect  the  existence  of  an  Event  of  Default
              hereunder.  A waiver or release  with  reference to any  one event
              shall not be construed as continuing, as a bar to, or as a  waiver
              or release of, any subsequent  right,  remedy or recourse as  to a
              subsequent event.

         12.  No Usury  Intended.  All  agreements between  Maker and Holder are
              -------------------
              expressly  limited so  that in no contingency or event whatsoever,
              whether by reason of:  error of fact or law;  payment,  prepayment
              or advancement of the  proceeds  hereof;  acceleration of maturity
              of the Outstanding  Principal   Balance,  or otherwise,  shall the
              amount  paid or agreed to be paid  to Holder  hereof  for the use,
              forbearance  or retention of the  money to be advanced  hereunder,
              including any charges  collected  or made in  connection  with the
              indebtedness  evidenced  by  this  Note  which may be  treated  as
              interest under  applicable  law,  if any, exceed the maximum legal
              limit  (if any such  limit  is  applicable)  under  United  States
              federal law or state law (to the extent  not  preempted by federal
              law, if any), now or hereafter  governing  the interest payable in
              connection  with  such  agreements.   If,  from any  circumstances
              whatsoever,  fulfillment  of  any  provision  hereof  at the  time
              performance  of  such   provision   shall  be  due  shall  involve
              transcending  the limit of  validity  (if any)  prescribed  by law
              which a court  of  competent   jurisdiction  may  deem  applicable
              hereto,  then ipso facto, the  obligation to be fulfilled shall be
              reduced  to  the  limit  of  such   validity,   and  if  from  any
              circumstances,  Holder  shall ever  receive  as interest an amount
              which would exceed the maximum  legal  limit (if any such limit is
              applicable),  such amount which  would be excessive interest shall
              be applied to the reduction of the  Outstanding  Principal Balance
              due  hereunder  and  not  to  the   payment  of  interest  or,  if
              necessary,  rebated to Maker.  This provision shall control  every
              other provision of all agreements between Maker and Holder.

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<PAGE>

         13.  Guaranty.  The  payment  of this Note is  guaranteed  by  Guaranty
              ---------
              Agreements  of even date  executed by Peter J. Salzano and Network
              Consulting Group, Inc.

         14.  Purpose of Loan.  Maker  certifies that the loan evidenced by this
              ----------------
              Note is obtained for business or commercial  purposes and that the
              proceeds   thereof  shall  not  be  used  for  personal,   family,
              household, or agricultural purposes.

         15.  Miscellaneous Provisions.
              -------------------------

              (a) Maker,  and each endorser and cosigner of this Note  expressly
                  grants to Holder  the right to  release or to agree not to sue
                  any other person, or to suspend the right to enforce this Note
                  against  such  other  person or to  otherwise  discharge  such
                  person;  and Maker, and each endorser and cosigner agrees that
                  the  exercise  of such rights by Holder will have no effect on
                  this  liability of any other person,  primarily or secondarily
                  liable  hereunder.  Maker,  and each  endorser and cosigner of
                  this Note  waives,  to the fullest  extent  permitted  by law,
                  demand for payment,  presentment for payment,  protest, notice
                  of protest, notice of dishonor,  notice of nonpayment,  notice
                  of acceleration of maturity, diligence in taking any action to
                  collect sums owing hereunder, any duty or obligation of Holder
                  to effect,  protect,  perfect,  retain or enforce any security
                  for  the  payment  of  this  Note or to  proceed  against  any
                  collateral before otherwise enforcing this Note, and the right
                  to plead as a defense to the  payment  hereof  any  statute of
                  limitations.

              (b) This Note and each payment of principal and interest hereunder
                  shall be paid when due without deduction or setoff of any kind
                  or nature whatsoever.

              (c) Maker  agrees to  reimburse  Holder for all costs,  including,
                  without limitation,  reasonable  attorneys' fees (including an
                  allocable  portion of  in-house  counsel  fees),  incurred  to
                  collect  this  Note  if  this  Note  is  not  paid  when  due,
                  including,  but not limited to,  attorneys' fees (including an
                  allocable  portion  of  in-house  counsel  fees)  incurred  in
                  connection  with any bankruptcy  proceedings  instituted by or
                  against Maker (including relief from stay litigation).

              (d) If any  provision  hereof is for any reason and to any extent,
                  invalid or  unenforceable,  then neither the  remainder of the
                  document  in  which  such  provision  is  contained,  nor  the
                  application  of the  provision to other  persons,  entities or
                  circumstances shall be affected thereby,  but instead shall be
                  enforceable to the maximum extent permitted by law.

              (e) This Note shall be a joint and  several  obligation  of Maker,
                  and of all endorsers and cosigners hereof and shall be binding
                  upon   them   and    their    respective    heirs,    personal
                  representatives, successors and assigns.

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<PAGE>

              (f) This Note may not be modified or amended orally, but only by a
                  modification  or  amendment  in  writing  signed by Holder and
                  Maker.

              (g) When the context and  construction so require,  all words used
                  in the  singular  herein  shall be deemed to have been used in
                  the plural and the  masculine  shall  include the feminine and
                  neuter and vice versa.  The word "person" as used herein shall
                  include   any   individual,    company,   firm,   association,
                  partnership,  corporation,  trust or other legal entity of any
                  kind whatsoever.

              (h) The headings of the  paragraphs  and sections of this Note are
                  for  convenience or reference only, are not to be considered a
                  part hereof and shall not limit or otherwise affect any of the
                  terms hereof.

              (i) In the event that at any time any  payment  received by Holder
                  hereunder  shall  be  deemed  by  final  order  of a court  of
                  competent  jurisdiction to have been a voidable  preference or
                  fraudulent  conveyance under the bankruptcy or insolvency laws
                  of the United States,  or shall  otherwise be deemed to be due
                  to any party other than Holder,  then, in any such event,  the
                  obligation to make such payment shall survive any cancellation
                  of this Note and/or  return  thereof to Maker and shall not be
                  discharged  or satisfied by any prior payment  thereof  and/or
                  cancellation  of this  Note,  but  shall  remain  a valid  and
                  binding  obligation  enforceable in accordance  with the terms
                  and  provisions  hereof,  and the amount of such payment shall
                  bear  interest at the Default Rate from the date of such final
                  order until repaid hereunder.


         IN WITNESS  WHEREOF Maker has executed this  Promissory  Note as of the
day and year first above written.

                                            "Maker"

                                            Rare Telephony, Inc.  (f/k/a  Washoe
                                            Technology Corporation)

                                            By   /s/ Thomas J. Vrabel
                                              ----------------------------------
                                                 Thomas J. Vrabel, President


                                            Cash Back Rebates LD.com, Inc.

                                            By:   /s/ Thomas J. Vrabel
                                              ----------------------------------
                                                  Thomas J. Vrabel, President


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<PAGE>

State of New Jersey

County of Passaic

Before me, the undersigned,  personally  appeared Thomas J. Vrabel,  known to me
(or  satisfactorily  proven) to be the person who executed the within instrument
on behalf of Rare Telephony,  Inc.  (f/k/a Washoe  Technology  Corporation)  and
acknowledged  that he executed the same for the purposes therein  contained.  In
witness whereof, I hereunto set my hand.

                                            /s/ Debra A. Caporale
                                            ------------------------------------
                                            (Notary Public)

                                            Dated:    5/4/00
                                                  ------------------------------


State of New Jersey

County of Passaic

Before me, the undersigned,  personally  appeared Thomas J. Vrabel,  known to me
(or  satisfactorily  proven) to be the person who executed the within instrument
on behalf of Cash Back Rebates LD.com,  Inc. and  acknowledged  that he executed
the same for the purposes therein contained.  In witness whereof, I hereunto set
my hand.

                                            /s/ Debra A. Caporale
                                            ------------------------------------
                                            (Notary Public)

                                            Dated:    5/4/00
                                                  ------------------------------


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