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                                                                  EXHIBIT 10.12
 
                            FIRST AMENDMENT TO LEASE

         1.   PARTIES

              1.1   THIS AGREEMENT made the ______day of _____,1997 is between
                    MONMOUTH/ATLANTIC REALTY ASSOCIATES L.P.("Lessor") whose
                    address is c/o Cali Realty Corporation, 11 Commerce Drive,
                    Cranford, New Jersey 07016 and DIGITAL LIGHTWAVE, INC.
                    ("Lessee"), whose address is 601 Cleveland Street, 5th
                    floor, Clearwater, Florida 34615

         2.   STATEMENT OF FACTS

              2.1   The parties have previously entered into a Lease dated _____
                    ("Lease") covering approximately 8,044 gross rentable
                    square feet ("Premises") in the building located at 1340
                    Campus Parkway, Building B, Wall, New Jersey ("Building"); 
                    and

              2.2   Lessee desires to occupy a portion of the third (3th) floor
                    of 1350 Campus Parkway, Wall, New Jersey on a temporary
                    basis.

         3.   AGREEMENT

                    NOW, THEREFORE, in consideration of the Premises and the
              covenants hereinafter set forth, Lessor and Lessee agree as 
              follows:

              3.1   Subject to all of the terms and conditions of the Lease
                    covering the Premises, except as set forth herein, Lessor
                    hereby leases to Lessee and Lessee hereby hires from Lessor
                    approximately 4,634 square feet on the third (3rd) floor of
                    1350 Campus Parkway, Wall, New Jersey, as shown on Exhibit
                    A attached hereto ("Temporary Premises"). Lessee has
                    inspected the Temporary Premises, is satisfied with the
                    condition thereof, and agrees to accept possession of the 
                    Temporary Premises in its "AS-IS" condition.

              3.2   The term applicable to the Temporary Premises shall
                    commence October 1, 1997 and shall terminate at the earlier
                    of (1) the completion of the premises under the lease, or 
                    (2) the date of cancellation of the lease pursuant to
                    Article 44 of the Lease.

              3.3   Lessee shall pay Lessor Fixed Basic Rent applicable to the
                    Temporary Term in monthly installments of THREE THOUSAND
                    ONE HUNDRED EIGHTY-FIVE AND 88/100 Dollars ($3,185.88) on
                    the first day of each month without any offset or abatement
                    of any kind whatsoever, provided that partial months' rents
                    shall be prorated.

              3.4   During the Temporary Term, the Temporary Premises shall be
                    insured according to the provisions of Article 31 Lessee's 
                    Insurance of the Lease.

              EXCEPT AS EXPRESSLY AMENDED HEREIN, the Lease dated ______ shall
         remain in full force and effect as if the same had been set forth in
         full herein, and Lessor and Lessee hereby ratify and confirm all of
         the terms and conditions thereof.

              THIS AGREEMENT shall be binding upon and inure to the benefit of
         the parties hereto and their respective legal representatives, 
         successors and permitted assigns.

              EACH PARTY AGREES that it will not raise or assert as a defense
         to any obligation under the Lease or this Agreement or make any claim
         that the Lease or this Agreement is invalid or unenforceable due to
         any failure of this document to comply with ministerial requirements
         including, but nor limited to, requirements for corporate seals,
         attestation, witnesses, notarizations, or other similar requirements,
         and each party hereby waives the right to assert any such defense or
         make any claim of invalidity or unenforceability due to any of the 
         foregoing.

              IN WITNESS WHEREOF, Lessor and Lessee have hereunto set their
         hands the date and year first above written, and acknowledge one to 
         the other that they possess the requisite authority to enter into this
         transaction and to sign this Agreement. 


         MONMOUTH/ATLANTIC REALTY                  DIGITAL LIGHTWAVE, INC.
         ASSOCIATES L.P., LESSOR                   LESSEE

         By:   Cali Sub VII, Inc.
               Managing General Partner
         
         By:                                       By:
               ------------------------                --------------------
               James G. Nugent                         Seth P. Joseph
               Vice President-Leasing                  Sr. Exec. Vice President