SECOND AMENDMENT TO 1996 RESTATED SECURITY AGREEMENT


         THIS SECOND AMENDMENT TO 1996 RESTATED  SECURITY  AGREEMENT is intended
to amend the 1996 RESTATED SECURITY  AGREEMENT (the "Agreement") dated as of May
3, 1996, and amended by the FIRST AMENDMENT TO 1996 RESTATED SECURITY  AGREEMENT
(the "First Amendment") dated as of June 28, 1996 by and among DATA TRANSMISSION
NETWORK  CORPORATION,  a  Delaware  corporation  having its  principal  place of
business  at Suite  200,  9110 West  Dodge  Road,  Omaha,  Nebraska  68114  (the
"Debtor"),  FIRST NATIONAL BANK OF OMAHA, a national banking  association having
its principal place of business at One First National  Center,  Omaha,  Nebraska
68102 as agent  ("Secured  Party") for itself and FIRST  NATIONAL  BANK,  WAHOO,
NEBRASKA,  a national banking association having its principal place of business
at Wahoo, Nebraska 68066 ("FNB-W"), NBD BANK, a bank organized under the laws of
the State of Michigan  having its  principal  place of business at 611  Woodward
Avenue, Detroit, Michigan 48226 ("NBD"), NORWEST BANK NEBRASKA, N.A., a national
banking  association  having its principal  place of business at 20th and Farnam
Streets, Omaha, Nebraska 68102 ("Norwest"),  FIRST BANK, NATIONAL ASSOCIATION, a
national banking  association having its principal place of business at 13th and
M Streets,  Lincoln,  Nebraska 68508 ("First Bank") (it being  acknowledged that
First Bank is the successor in interest to FirsTier Bank, National  Association,
Lincoln,  Nebraska  ("FirsTier")),  THE BOATMEN'S  NATIONAL BANK OF ST. LOUIS, a
national  banking  association  having its  principal  place of  business at One
Boatmen's Plaza, 800 Market Street, P.O. Box 236, St. Louis, Missouri 63166-0236
("Boatmen's"),  FARM CREDIT SERVICES OF THE MIDLANDS,  PCA, a production  credit
association ("Farm Credit") in care of AGAMERICA,  FCB, a farm credit bank doing
business at 206 South 19th Street, Omaha, Nebraska 68102-1745 ("AgAmerica"), THE
SUMITOMO BANK,  LIMITED,  a Japanese bank being represented by its office at 200
North  Broadway,  Suite 1625,  St. Louis,  Missouri 63102 and acting through its
Chicago  branch  ("Sumitomo"),  MERCANTILE  BANK OF ST. LOUIS,  N.A., a national
banking  association  having its principal  place of business at One  Mercantile
Center, 7th and Washington Streets,  St. Louis,  Missouri 63101  ("Mercantile"),
and BROADCAST  PARTNERS,  a general  partnership  having its principal  place of
business at 11275 Aurora Avenue, Des Moines,  Iowa 50322 ("Broadcast  Partners")
(collectively,  and together  with any other Lender that  hereinafter  becomes a
party to any "Loan Agreement" as hereinafter defined, the "Lenders").

         1. BANK OF MONTREAL, a Canadian bank being represented by its office at
430 Park Avenue,  New York,  New York 10022 is hereby added to the definition of
"Lenders" referenced in the Agreement.

         2.       Replace clause (ii)  of Section 3 with the following:  "under
the 1996 Revolving  Credit  Agreement dated as of July 31, 1996, as amended from
time to time between the Debtor and First National Bank of Omaha, First National
Bank,  Wahoo,  Nebraska,  Norwest Bank  Nebraska,  N.A.,  NBD Bank,  Farm Credit
Services of the Midlands,  PCA, The Sumitomo Bank,  Limited,  Mercantile Bank of
St. Louis,  N.A.,  First Bank,  National  Association,  Bank of Montreal and The
Boatmen's National Bank of St. Louis."

                                        1


                                    - 224 -
<PAGE>


         IN WITNESS WHEREOF, the undersigned have executed this SECOND AMENDMENT
TO 1996 RESTATED SECURITY AGREEMENT as of July 31, 1996.


                           DATA TRANSMISSION NETWORK CORPORATION


                                             By
                                          Title


                          FIRST NATIONAL BANK OF OMAHA


                                              By
                                           Title




                                        2


                                    - 225 -
<PAGE>