<PAGE>

                                                                   Exhibit 10.27

                                                                 October 2, 1998

                                                                     $900,000.00


                             DEMAND PROMISSORY NOTE


                  AMNEX, INC., A New York corporation ("AMNEX") and AMERICAN
NETWORK EXCHANGE, INC., a Delaware corporation and wholly-owned subsidiary of
AMNEX ("ANEI", and together with AMNEX, the "Makers"), for value received,
hereby jointly and severally promise to pay to the order of ROTTERDAM VENTURES,
INC., a New York corporation (the "Holder"), within fifteen (15) days following
the date of receipt of demand for payment (the "Due Date"), at the offices of
the Holder indicated in paragraph 5 hereof the aggregate principal sum of NINE
HUNDRED THOUSAND DOLLARS ($900,000) in such coin or currency of the United
States of America as at the time of payment shall be legal tender for the
payment of public and private debts and to pay interest on such principal sum
from the date hereof at a fluctuating rate per annum at all times equal to the
prime rate of interest announced from time to time by The Chase Manhattan Bank
plus two percent (2%) (the "Note Rate"). Accrued interest on the unpaid
principal balance of this Demand Promissory Note ("Note") shall be payable on
the first business day of each month commencing November 2, 1998, and on the Due
Date.

1.   Registered Owner. The Makers may consider and treat the person in whose
     name this Note shall be registered as the absolute owner thereof for all
     purposes whatsoever (whether or not this Note shall be overdue) and the
     Makers shall not be affected by any notice to the contrary. The registered
     owner of this Note shall have the right to transfer it by assignment and
     the transferee thereof upon his registration as owner of this Note, shall
     become vested with all the powers and rights of the transferor.
     Registration of any new owner shall take place upon presentation of this
     Note to AMNEX at its offices together with an assignment duly
     authenticated. In case of transfers by operation of law, the transferee
     shall notify the Makers of such transfer and of his address, and shall
     submit appropriate evidence regarding the transfer so that this Note may be
     registered in the name of the transferee. This Note is transferable only on
     the books of the Makers by the holder hereof in person or by attorney, on
     the surrender hereof duly endorsed. Communications sent to any registered
     owner shall be effective as against all holders or transferees of this Note
     not registered at the time of sending the communication.

2.   Redemption. The Holder, by its acceptance of this Note, hereby acknowledges
     that,subject to the provisions of paragraph 7 hereof, at any time, and
     from time to time, notwithstanding the lack of demand for payment on the
     part of the Holder, any of the Makers may, at its option, by written notice
     given to the Holder, elect to redeem and prepay all or any portion of the
     outstanding principal indebtedness evidenced by this Note, together with
     accrued


                                                                     Page 1 of 6

<PAGE>

     interest thereon, without premium or penalty. Any such notice of a Maker's
     election to redeem and prepay as provided for hereinabove shall be given
     not less than five (5) business days prior to the date fixed in such notice
     as the date for redemption of this Note (the "Redemption Date"). 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.


3.   Default Rate of Interest: Late Charge. In the event the Makers shall fail
     to pay all or any portion of the principal amount hereof on or before the
     Due Date, any such unpaid amount shall bear interest, for each day from the
     Due Date, until paid in full, at a fluctuating rate per annum at all times
     equal to the Note Rate plus five percent (5%) instead of the Note Rate as
     hereinabove provided, payable upon demand. In the event the Makers shall
     fail to pay timely any other amount due hereunder, the Makers, jointly and
     severally, agree to make a payment, in addition to all other required
     payments hereunder, equal to two percent (2%) of the overdue payment.

4.   Applicable Law. This Note is issued under and shall for all purposes be
     governed by and construed in accordance with the laws of the State of New
     York, excluding choice of law rules thereof.

5.   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 prepaid, overnight
     mail or courier, or telecopier as follows:

     If to Holder at:         695 Rotterdam Industrial Park
                              Schenectady, New York 12306-1989
                              Attention:   David M. Buicko
                              Telecopier Number: (518) 356-5334

     With a copy to:          Steven K. Porter, Esq.
                              695 Rotterdam Industrial Park
                              Schenectady, New York 12306-1989
                              Telecopier Number: (518) 357-2534

     If to AMNEX at:          145 Huguenot Street
                              New Rochelle, New York 10801
                              Attention: Chairman
                              Telecopier Number: (914) 235-1339


                                                                     Page 2 of 6

<PAGE>


     With a copy to:          Guy Longobardo, Esq.
                              145 Huguenot Street
                              New Rochelle, New York 10801
                              Telecopier Number: (914) 235-1339

     If to ANEI at:           100 West Lucerne Circle, Suite 600
                              Orlando, Florida 32801
                              Attention: President
                              Telecopier Number: (407) 481-2560

     With a copy to:          Guy Longobardo, Esq.
                              145 Huguenot Street
                              New Rochelle, New York 10801
                              Telecopier Number: (914) 235-1339



     or any such other address as the Holder or any Maker may specify by notice
     given to the other party in accordance with this paragraph 5.


6.   Use of Proceeds. Of the $900,000 principal balance hereof, $500,000 is
     being used to refinance that certain Demand Promissory Note dated August 2,
     1998 (the "August Note"), from Makers to Holder and $400,000 is being
     advanced directly to the Makers. The August Note is superseded, amended and
     restated in its entirety by this Note.


7.   Conversion Option.

     1.   Subject to the provisions of Paragraph 7.b.,in lieu of receiving a
          payment in cash, either after demand or in connection with any
          prepayment of this Note by the Makers, the Holder may require that
          AMNEX issue shares of the common stock valued at 65.6 cents per share
          to Holder. At the time of demand, or not less than one (1) business
          day prior to the redemption date, Holder shall inform Makers whether
          or not Holder desires to receive cash or shares of stock in connection
          with any payment or prepayment of this Note. AMNEX shall have no duty
          to issue any fractional shares and, to the extent that any interest or
          principal cannot be paid by the delivery of a share of AMNEX common,
          because the value of the share exceeds the remaining amount owed, such
          amount shall be paid in cash. In calculating the amount of common
          stock required to be paid in order to satisfy this Note in full, the
          Holder shall be entitled to include a reasonable period of time to
          allow for the actual delivery of shares of AMNEX common stock to
          Holder. If Holder shall fail to notify Makers of Holder's election to
          receive shares of common stock instead of cash, the Makers shall pay
          cash.


                                                                     Page 3 of 6

<PAGE>

     2.   The provisions of Paragraph 7.a. shall become automatically operative
          from and after, and to the extent that AMNEX has notified in a timely
          fashion any and all existing shareholders with preemptive rights to
          participate in the purchase of the Note, including the Conversion
          Option, and such rights have been waived or exercised in accordance
          with their terms. Without limiting the generality of the foregoing,
          the effectiveness of Paragraph 7.a. shall not require any further
          action by AMNEX or the Holder other than sending and receiving
          notification of the aforesaid waiver and/or exercise and, in the case
          of one or more exercises, adjustment of the Note accordingly. AMNEX
          agrees to send appropriate notices to all shareholders having
          preemptive rights no later than three (3) business days after the date
          of this Note.

8.   Waivers. Makers hereby waive presentment for payment, protest and demand,
     and notice of protest, demand and/or dishonor and nonpayment of this Note,
     and all other notices of demands otherwise required by law that Makers may
     lawfully waive. The Makers expressly agree that this Note, or any payment
     hereunder may be extended from time to time without in any way affecting
     the liability of Makers. No unilateral consent or waiver by Holder 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 Holder.


9.   Consent to Jurisdiction: Jury Trial Waiver. Makers hereby submit 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 Makers
     obligations under and with respect to this Note, and expressly waive any
     and all obligations they may have as to venue of any of such courts. MAKERS
     AND HOLDER 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 Makers or Holder, 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 MAKERS AND HOLDER, 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.


                                                                     Page 4 of 6

<PAGE>

10.  Savings Clause. All agreements between Makers and Holder 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 Holder for the
     use, forbearance or detention of the indebtedness evidenced hereby exceed
     the maximum permissible under applicable law. Any interest received by
     Holder 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 Makers and Holder.

11.  Attorney's 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, the Makers shall pay (on demand)
     all reasonable costs and expenses of collection incurred, including
     reasonable attorneys' fees.

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

13.  Miscellaneous.

     1.   This Note constitutes the rights and obligations of the Holder and the
          Makers. No provision of this Note may be modified except by an
          instrument in writing signed by the party against whom the enforcement
          of any modification is sought.

     2.   Payment of interest due under this Note prior to the Due Date or
          Redemption Date, as the case may be, shall be made to the registered
          holder of this Note. Payment of principal and interest due hereunder
          on the Due Date or Redemption Date, as the case may be, shall be made
          to the registered holder of this Note in accordance with the terms
          hereof following presentation of this Note upon or after such
          applicable date. No interest shall be due on this Note for such period
          of time that may elapse between the Due Date or Redemption Date, as
          the case may be, and its presentation for payment.

     3.   No recourse shall be had for the payment of the principal of or
          interest on this Note against any officer, director or agent of any
          Maker, past, present or future, all such liability of the officers,
          directors and agents being waived, released and surrendered by the
          Holder hereof by the acceptance of this Note.


                                                                     Page 5 of 6

<PAGE>

                  IN WITNESS WHEREOF, the Makers have caused this Note to be
signed on its behalf in its corporate name, by its duly authorized officer, all
as of the day and year first above written.


                                        AMNEX, INC.


                                        By: _________________________________
                                        Name:
                                        Title:



                                        AMERICAN NETWORK EXCHANGE, INC.


                                        By: _________________________________
                                        Name:
                                        Title:


                                                                     Page 6 of 6