March 1, 1997

Brian E. King
National Telecom USA, Inc.
675 Morris Avenue
Springfield, New Jersey 07081

Dear Mr. King:

Reference is made to that certain Renewal and Modification Agreement dated as of
February 28, 1997 (the  "Renewal  Agreement")  by and between  American  Network
Exchange,  Inc.  ("AMNEX") and National Telecom USA, Inc.  ("NTI"),  pursuant to
which, among other things,  AMNEX, Inc., the parent company of AMNEX,  agreed to
issue and  deliver to NTI or Brian E. King,  its sole  shareholder,  or to their
designees,  a total of 346,154  shares of the Common  Stock of AMNEX,  Inc.,  in
accordance with the terms and provisions of the Renewal  Agreement.  Such number
of shares was calculated  based upon the average  closing  selling price for the
AMNEX,  Inc.  Common  Stock  during the  eighty  two (82) day  period  ending on
February 28, 1997, which average price was $3.25 per share.

It is  acknowledged  and agreed  that,  in lieu of issuing and  delivering  such
346,154 shares to NTI or Brian E. King or their designees, as aforesaid,  NTI or
Brian E. King shall be  entitled  to receive  the sum of one million one hundred
twenty five thousand dollars  ($1,125,000),  which sum shall be wire transferred
by AMNEX to a depository designated in writing by NTI or Brian E. King, in whole
or part, as hereinafter provided, on the earlier to occur of (i) March 31, 1997;
or (ii) the third  business day following the date that AMNEX  receives  written
notification  from NTI,  Brian E. King or a broker dealer on their behalf,  that
any of them has  purchased  shares of the AMNEX,  Inc.  Common Stock in the open
market (the  "Settlement  Date").  It is  understood  and agreed that the entire
$1,125,000 may be utilized on one occasion to purchase such shares,  or portions
of such sum may be utilized on various  occasions to purchase  groupings of such
shares.  If the latter  approach is  employed,  AMNEX shall only be obligated to
wire  transfer  such portion of the  $1,125,000 as shall be necessary to satisfy
the purchase of such shares being made on the relevant Settlement Date. In all
cases, the form of instruction letter attached hereto as Exhibit A shall be 
transmitted to broker dealers purchasing such shares on NTI's or Brian E. King's
behalf.

In the event that, on or before March 31, 1997, (i) the entire sum of $1,125,000
shall have been utilized to purchase  shares of AMNEX,  Inc. Common Stock in the
open market; (ii) all such shares shall have been purchased on NTI's or Brian E.
King's  behalf  by a broker  dealer  of  AMNEX,  Inc.'s  choice;  and  (iii) the
aggregate  number of 


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Brian E. King
National Telecom USA, Inc.
March 1, 1997
Page 2


such shares delivered to NTI and Brian E. King  (collectively,  the "Open Market
Shares")  shall be less than  346,154,  then AMNEX,  Inc.  shall be obligated to
issue and  deliver  to NTI or Brian E. King or their  designees  that  number of
unregistered  shares of the  Common  Stock of  AMNEX,  Inc.  as shall  equal the
difference between 346,154 and the actual aggregate number of Open Market Shares
delivered  to NTI or  Brian  E.  King.  For  purposes  hereof,  such  number  of
unregistered  shares to be delivered to NTI or Brian E. King or their  designees
shall hereinafter be referred to collectively as the "Spread Shares".

It is  expressly  understood  and agreed that (i) no Spread  Shares may be sold,
assigned,  mortgaged, pledged, hypothecated or otherwise transferred or disposed
of for a period  of two (2) years  from the date of such  delivery  without  the
written  consent  of AMNEX,  Inc.;  and (ii) all stock  certificates  evidencing
ownership of any Spread Shares shall bear a  restrictive  legend to such effect.
AMNEX agrees to cause the Spread  Shares,  if any, to be issued and delivered to
NTI or Brian E. King or their designees no later than April 30, 1997, subject to
and in accordance with, the terms and provisions of the Renewal  Agreement.  For
purposes of complying with any holding period  mandated by Rule 144  promulgated
under the  Securities  Act of 1933,  and for no other  purpose  whatsoever,  the
original issuance date of the Spread Shares shall,  unless otherwise provided by
law or rule, be deemed to be February 28, 1997.

It is further expressly understood and agreed that (i) no Open Market Shares may
be sold, assigned,  mortgaged, pledged, hypothecated or otherwise transferred or
disposed of until March 31, 1998 without the written consent of AMNEX, Inc.; and
(ii) all stock certificates evidencing ownership of any Open Market Shares shall
bear a restrictive  legend to such effect. In furtherance of the foregoing,  NTI
and Brian E. King agree to execute and deliver to AMNEX,  Inc.'s  transfer agent
and broker  dealer an  instruction  letter in form and  substance  acceptable to
AMNEX,  which  letter  clearly  authorizes  such  persons  to issue or cause the
issuance of all stock  certificates  for Open Market Shares in NTI's or Brian E.
King's name with the restrictive legend described above.

Notwithstanding  anything to the contrary  contained herein,  AMNEX shall not be
obligated  to issue any  Spread  Shares  unless NTI and Brian E. King shall have
complied  with the  provisions of the  immediately  preceding  paragraph.  It is
acknowledged and agreed that all representations and warranties contained in the
Renewal Agreement with respect to the 346,154 shares of AMNEX, Inc. Common Stock
shall apply with equal force and effect to the Spread Shares.

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Brian E. King
National Telecom USA, Inc.
March 1, 1997
Page 3


The parties agree that the terms of this letter agreement may not be modified or
waived except by a written instrument signed by the parties hereto.

If the foregoing accurately and completely sets forth our agreement with respect
to the subject matter hereof,  please so indicate by signing below and returning
this letter to the undersigned.

Very truly yours,

AMNEX, INC.

By:/s/

Name:__________________________

Title:_________________________

ACKNOWLEDGED AND AGREED:

NATIONAL TELECOM USA, INC.

By:/s/

Name:__________________________

Title:_________________________


/s/ Brian E. King
--------------------------------
Brian E. King, individually


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                                    EXHIBIT A

                   FORM OF INSTRUCTION LETTER TO BROKER DEALER



[name of contact]
[name of broker dealer]
[street address]
[city] [state] [zipcode]


Dear ____________________:


This is to advise you that all purchases of AMNEX, Inc. Common Shares to be made
by you on behalf of National Telecom USA, Inc. or Brian E. King are to be 
treated as 10b-18 purchases.

Accordingly,  please ensure that such purchases are made in compliance  with the
safe harbor provisions of Rule 10b-18 promulgated under the Securities  Exchange
Act of 1934.

Thank you for your cooperation.

Very truly yours,


[name of transmitting person]






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