SECOND
                             MASTER REAFFIRMATION OF
                      PARENT PLEDGE AND SUPPORT AGREEMENTS


                  This SECOND MASTER  REAFFIRMATION OF PARENT PLEDGE AND SUPPORT
AGREEMENTS (this  "Reaffirmation")  is executed as of this 6th day of September,
1996 by American  Communications  Services,  Inc., a Delaware  corporation  (the
"Parent"),  in  favor  of  AT&T  Credit  Corporation,   a  Delaware  corporation
("Lender").

                                   WITNESSETH

                  WHEREAS, American Communications Services of Louisville, Inc.,
American  Communication  Services of Fort Worth,  Inc.,  American  Communication
Services of Columbia,  Inc. and American  Communication  Services of Greenville,
Inc.,  and American  Communication  Services of El Paso,  Inc.  (each a Delaware
corporation), entered into those certain Loan and Security Agreements each dated
respectively  as of October  16,  1994,  February  28,  1995,  June 30, 1995 and
September  9, 1995,  as  amended  (collectively,  as so  amended  and as further
amended, restated or modified, the "Loan Agreements") with Lender;

                  WHEREAS,  to induce  Lender to enter into the Loan  Agreement,
Parent executed and delivered those certain Parent Pledge and Support Agreements
each  dated as of  October  16,  1994,  February  28,  1995,  June 30,  1995 and
September  9, 1995,  as  amended  (collectively,  as so  amended  and as further
amended, restated or modified, the "Pledge Agreements") in favor of the Lender;

                  WHEREAS,  the parties to the Loan Agreements are entering into
that certain Second Master Amendment to Loan and Security Agreements, Waiver and
Equipment Notes Modification  Agreement (the "Amendment") of even date herewith;
and

                  WHEREAS, it is a condition precedent to the effectiveness of
the Amendment that Parent execute and deliver this Reaffirmation;

                  NOW, THEREFORE,  for and in consideration of the foregoing and
for other good and valuable consideration,  the receipt and sufficiency of which
are hereby acknowledged, the Parent hereby agrees as follows:

                  1. Reaffirmation of Pledge Agreements. The Parent acknowledges
that it has  received  and reviewed the  Amendment  and  reaffirms  that (a) the
pledge of the "Pledged Stock" as defined in the respective Pledge Agreements and
the liens and security  interest  granted therein and (b) the Pledge  Agreements
and the liens and security interest granted therein shall continue in full force
and  effect in  accordance  with  their  respective  terms  notwithstanding  the
execution and delivery of the Amendment.

                  2.  Governing Law and Jurisdiction.  This Reaffirmation shall
be construed in accordance with and governed by the internal laws of the State
of New Jersey, without giving effect to any conflicts of laws principles.



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                  3.  Execution in Counterparts.  This Reaffirmation may be
executed in any number of counterparts, each of which shall be an original, but
all of which shall together constitute one and the same agreement.












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                  IN WITNESS  WHEREOF,  the  parties  hereto  have  caused  this
Reaffirmation to be duly executed by their duly authorized representatives as of
the day and year first written above.

                                     AMERICAN COMMUNICATIONS SERVICES, INC.

                                     By: /s/ RICHARD A. KOZAK
                                     Name: Richard A. Kozak
                                     Title: President & Chief Executive Officer






Acknowledged and agreed to as of the day and year first written above.

AT&T CREDIT CORPORATION

By: /s/ EDWARD W. ANDREWS, JR.
Name: Edward W. Andrews, Jr.
Title: President













































226889.01  GABBAY, ALAN M.  CH   September 30, 1996 (7:19AM)