PROMISSORY NOTE



$500,000                                                     September 18, 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 Five Hundred Thousand Dollars
($500,000), together with all accrued unpaid interest thereon and all other sums
remaining  due  and  owing  hereunder  and  under  the  Security  Agreement  (as
hereinafter  defined).  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 ten percent (10%)
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

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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.


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  and/or under the Security
Agreement, next to accrued but unpaid interest, and then to the principal amount
outstanding.


Security. Payment of the principal amount of, and accrued interest on, this Note
is  secured  by, a  security  interest  in certain  assets of  Crescent  granted
pursuant to a certain  Security  Agreement of even date  herewith by and between
Crescent and the Lender (the "Security Agreement").  This Note is being executed
in conjunction with, and is entitled to the benefits of, the Security Agreement.


Remedies After Default. Upon the occurrence of an Event of Default (as such term
is defined in the  Security  Agreement),  the entire  unpaid  principal  balance
hereof,  together  with  accrued  unpaid  interest  thereon  and all other  sums
remaining due and owing hereunder and under the Security  Agreement 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 as well as those remedies set
forth in the Security  Agreement and this Note,  and one or more  executions may
forthwith issue on any judgment or judgments obtained by virtue thereof,  and 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 under the Security  Agreement
or permitted by law.  Irrespective  of the exercise or nonexercise of any of the
aforesaid  rights,  after the occurrence of an Event of Default and 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 ten
percent (10%) per annum.


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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


         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






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     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 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

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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.


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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.


     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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