PROMISSORY NOTE



$800,000                                                      September 30, 1997




     FOR VALUE RECEIVED, AMNEX, INC., a New York corporation ("AMNEX"), AMERICAN
NETWORK EXCHANGE,  INC., a Delaware  corporation and wholly-owned  subsidiary of
AMNEX ("ANEI"),  and CRESCENT PUBLIC COMMUNICATIONS INC., a New York corporation
and wholly-owned  subsidiary of AMNEX  ("CRESCENT",  and collectively with AMNEX
and ANEI, the  "Borrower"),  hereby jointly and severally  promise to pay to the
order of ROTTERDAM  VENTURES,  INC., a New York corporation  ("Lender"),  on the
first  anniversary  (the "Maturity  Date") of the date of this  Promissory  Note
("Note"),  at its principal  office at Rotterdam  Industrial  Park,  Building 6,
Schenectady, New York 12306, the principal sum of Eight Hundred Thousand Dollars
($800,000), together with all accrued unpaid interest thereon and all other sums
remaining  due and owing  hereunder.  Interest  shall  accrue  and be payable in
arrears,  on any and all principal  amounts  outstanding  and  remaining  unpaid
hereunder from time to time from the date hereof until payment in full hereof at
the rates  hereinafter  provided,  such  interest  to be payable as  hereinafter
provided. Interest shall be calculated on the basis of the actual number of days
elapsed  over a year of three  hundred  sixty  (360) days and shall be at a rate
(whether  before or after  maturity,  except  as  hereinafter  provided)  of six
percent (6%) per annum.  Prior to the Maturity  Date,  interest shall be payable
monthly in arrears on the first day of each calendar month  commencing  November
1, 1997 and  continuing  on the same day of each  successive  month,  and on the
Maturity Date.


Methods  of  Payment.  Payments  of both  principal  and  interest  as  required
hereunder  shall be made in lawful  money of the  United  States of  America  in
immediately  available  funds (or,  with  respect to interest  only,  by company
check) at the office of Lender set forth  above.  If any payment of principal or
interest  shall become due on a Saturday,  Sunday,  or on any other day on which
banking  institutions are authorized or obligated by law to close,  such payment
shall be made on the next  succeeding  business  day and such  extension of time
shall in such case be included in  computing  interest in  connection  with such
payment.


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Prepayment.  This Note may be prepaid in whole or in part, at any time,  without
premium or penalty. Any payments received on this Note shall be applied first to
any unpaid  fees or other  sums due and owing  hereunder,  next to  accrued  but
unpaid interest, and then to the principal amount outstanding.

Remedies  After  Default.  Upon the failure of the  Borrower to make an interest
payment when due  hereunder,  which  failure  continues for a period of ten (10)
days after the same shall be due, the entire unpaid  principal  balance  hereof,
together with accrued unpaid  interest  thereon and all other sums remaining due
and owing  hereunder,  shall, at the option of Lender and without further notice
or demand to the  Borrower,  become  immediately  due and payable and Lender may
forthwith exercise any and all remedies available to Lender at law and in equity
and one or more  executions  may  forthwith  issue on any  judgment or judgments
obtained by virtue thereof.  No failure on the part of Lender to exercise any of
Lender's  rights  hereunder  shall  be  deemed  a  waiver  of any  such  rights.
Irrespective of the exercise or nonexercise of any of the aforesaid  rights,  if
the entire amount of any required  principal and/or interest payment is not paid
in full within ten (10) days after the same is due, Borrower shall pay to Lender
a late fee equal to five percent (5%) of the required payment. This charge shall
be in addition to, and not in lieu of, any other remedy Lender may have,  and is
in addition to any reasonable  attorney fees and other sums payable hereunder or
permitted  by law.  Irrespective  of the exercise or  nonexercise  of any of the
aforesaid rights, after the acceleration of the principal balance hereof, at the
option of the Lender,  Borrower  will pay, on demand,  interest on the principal
balance  of this  Note then  outstanding  at the rate  (the  "Default  Rate") of
fifteen percent (15%) per annum in lieu of six percent (6%) per annum.

Notices.  Any and all notices or other  communications or deliveries required or
permitted  to be given or made  pursuant to any of the  provisions  of this Note
shall be in writing  and shall be deemed to have been duly given or made for all
purposes  when hand  delivered or sent by certified or registered  mail,  return
receipt requested and postage pre-paid,  overnight mail or courier or telecopier
(receipt confirmed) as follows:

     If to Lender at:

     Rotterdam Ventures, Inc.
     Building 6, East Road
     Schenectady, New York 12306
     Attention: David M. Buicko, Chief Operating Officer
     Telecopier Number: (518) 356-5334



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     and

     Steven K. Porter, Esq.
     Rotterdam Industrial Park, Building 6
     Schenectady, New York 12306
     Telecopier Number (518) 357-2534

     if to the BORROWER at:

     6 Nevada Drive, Building C
     Lake Success, New York 11042
     Attention: Chief Executive Officer or President
     Telecopier Number: (516) 326-7987

     With copies to:

     Richard Stoun and
     Amy S. Gross, Esq.
     American Network Exchange, Inc.
     100 West Lucerne Circle
     Suites 500 and 401
     Orlando, FL 32801
     Telecopier Numbers: (407) 425-3265
                         (407) 481-2560


Waivers. Borrower hereby waives presentment for payment, protest and demand, and
notice of protest,  demand and/or  dishonor and nonpayment of this Note, and all
other  notices or demands  otherwise  required by law that Borrower may lawfully
waive. The Borrower  expressly agrees that this Note, or any payment  hereunder,
may be extended from time to time, without in any way affecting the liability of
Borrower.  No unilateral  consent or waiver by Lender with respect to any action
or failure to act  which,  without  consent,  would  constitute  a breach of any
provision  of this Note shall be valid and binding  unless in writing and signed
by Lender.

Governing Law. The rights and obligations of Borrower and all provisions  hereof
shall be governed by and construed in  accordance  with the laws of the State of
New York applicable to contracts made and performed in said State.

Consent to  Jurisdiction:  Jury Trial  Waiver.  Borrower  hereby  submits to the
jurisdiction  of the  courts  of the  State of New York  located  in the City of
Schenectady  and the United States  District Court for the Northern  District of
New York, as well as to the jurisdiction of all courts to which an

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appeal may be taken or other review  sought from the aforesaid  courts,  for the
purpose  of any  suit,  action or other  proceeding  arising  out of  Borrower's
obligations under or with respect to this Note, and expressly waives any and all
obligations  it may have as to venue in any of such courts.  BORROWER AND LENDER
EACH HEREBY  WAIVES  TRIAL BY JURY IN ANY  ACTION,  PROCEEDING  OR  COUNTERCLAIM
BROUGHT  BY  EITHER  OF  THEM  AGAINST  THE  OTHER  ON  ANY  MATTERS  WHATSOEVER
(INCLUDING,  WITHOUT LIMITATION,  ANY ACTION, PROCEEDING OR COUNTERCLAIM ARISING
OUT OF OR IN ANY  WAY  CONNECTED  WITH  THIS  NOTE,  OR ANY OF THE  TRANSACTIONS
CONTEMPLATED  HEREIN).  No party to this Note,  including but not limited to any
assignee of or successor  to Borrower or Lender,  shall seek a jury trial in any
lawsuit, proceeding, counterclaim, or any other litigation procedure based upon,
or arising out of, this Note or the relationship  between the parties.  No party
will seek to consolidate any such action, in which a jury trial has been waived,
with any other  action in which a jury trial  cannot be or has not been  waived.
THE  PROVISIONS  OF THIS  PARAGRAPH  HAVE BEEN FULLY  DISCUSSED  BY BORROWER AND
LENDER, AND THESE PROVISIONS SHALL BE SUBJECT TO NO EXCEPTIONS.  NO PARTY HAS IN
ANY WAY AGREED WITH OR  REPRESENTED  TO ANY OTHER PARTY THAT THE  PROVISIONS  OF
THIS PARAGRAPH WILL NOT BE FULLY ENFORCED IN ALL INSTANCES.

Savings Clause.  All agreements between Borrower and Lender are hereby expressly
limited  so that in no  contingency  or event  whatsoever,  whether by reason of
acceleration  of maturity of the  indebtedness  evidenced  hereby or  otherwise,
shall the amount paid or agreed to be paid to Lender for the use, forbearance or
detention of the indebtedness  evidenced  hereby exceed the maximum  permissible
under  applicable  law. Any  interest  received by Lender which would exceed the
maximum  permissible  under  applicable law shall be applied to the reduction of
the principal balance evidenced hereby and not to the payment of interest.  This
provision shall control every other provision of all agreements between Borrower
and Lender.

Attorneys'  Fees. If this Note shall not be paid when due and shall be placed by
the holder  hereof in the hands of any attorney for  collection,  through  legal
proceedings or otherwise, Borrower will pay (on demand) all reasonable costs and
expenses of collection incurred, including reasonable attorneys' fees.

Continued  Liability.  Borrower shall remain primarily liable on this Note until
full payment,  unaffected by any agreement or transaction between Lender and any
subsequent Borrower as to payment of principal, interest or other moneys, by any
forbearance  or extension of time,  guaranty or assumption by others,  or by any
other matter, as to all of which notice is hereby waived by Borrower.

Section  Headings.  Any section  headings in this Note are  included  herein for
convenience of reference  only and shall not  constitute  apart of this Note for
any other purpose.


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     IN WITNESS  WHEREOF,  Borrower  has caused  this Note to be executed by its
duly authorized officer as of the day and year first above written.


                                  Borrower:

                                  AMNEX, INC.

                                  By: ____________________________
                                  Name:  Peter Izzo
                                  Title: President


                                  AMERICAN NETWORK EXCHANGE, INC.

                                  By: ________________________________
                                  Name:  Peter Izzo
                                  Title: Chief Executive Officer


                                  CRESCENT PUBLIC COMMUNICATIONS INC.

                                  By: __________________________________
                                  Name:  Peter Izzo
                                  Title: President and Chief Executive Officer





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