FIRST AMENDMENT TO LEASE AGREEMENT


         THIS FIRST  AMENDMENT TO LEASE  AGREEMENT is entered into as of the day
of  March,  1998,  by and  between  VTEL  Corporation,  a  Delaware  corporation
("Tenant"), and WB One and Two, Ltd., a Texas limited partnership ("Landlord").

                                    Recitals

         A. Tenant and 2800 Industrial,  Inc. ("2800") entered into that certain
Lease Agreement dated January 30, 1998 (the "Lease"), relating to Tenant's lease
of  approximately  132,747 square feet of rentable area in the office  buildings
known as Wild Basin One and Two,  Austin,  Texas, as more fully described in the
Lease.

         B. 2800 has assigned to Landlord  all of the right,  title and interest
of 2800 in and to the Lease,  and Landlord has assumed all of the obligations of
2800 under the Lease.

         C.  Landlord  and  Tenant  desire  to amend  the  Lease as  hereinafter
provided.

                                    Amendment

         In   consideration   of  the  premises  and  other  good  and  valuable
consideration,  the receipt and  sufficiency  of which are hereby  acknowledged,
Landlord and Tenant hereby amend the Lease as follows:

         1. The following  sentence is hereby added to Section 6.2 of the Lease,
immediately following the third grammatical sentence of Section 6.2:

         "Notwithstanding  the immediately  preceding sentence or the provisions
         of clause (9) of Section 7.1(b) below,  Landlord may include in monthly
         Operating Costs one-twelfth (1/12) of Landlord's reasonable estimate of
         Taxes for the  calendar  year to which  such  monthly  Operating  Costs
         applies,  subject to adjustments  under Section 9.3 below, and Tenant's
         payment of such monthly estimate,  as adjusted,  shall satisfy Tenant's
         obligation  for the payment of Taxes under this Section 6.2;  provided,
         however,  Landlord  shall  have the right to  include  Taxes in monthly
         Operating  Costs  under this  sentence  only to the extent  Landlord is
         required to escrow Taxes under any loan secured by a first lien deed of
         trust encumbering the Building and the Land."

         2. Unless defined  differently  herein or the context clearly  requires
otherwise, all initially capitalized terms used in this Amendment shall have the
meanings  ascribed to them under the Lease.  Except as expressly amended hereby,
the Lease shall remain unchanged and in full force and effect.







         EXECUTED as of the date first written above.

                                        TENANT:

                                        VTEL CORPORATION, a Delaware corporation


                                        By:
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                                        Name:
                                              ----------------------------------
                                        Title:
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                                        LANDLORD:

                                        WB ONE AND TWO, LTD., a Texas limited
                                        partnership

                                        By:      WB One and Two, Inc., a Texas
                                                 corporation, General Partner


                                                  By:
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                                                  Name:
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                                                  Title:
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