TI/IAT
                                                         Agreement #MSCI10850
                                                         Page 1 of 2
                                                         05/21/97
                               AMENDMENT NO. 1 
                                   BETWEEN 
                        TEXAS INSTRUMENTS INCORPORATED 
                                     AND 
                                    IAT AG 

WHEREAS, TEXAS INSTRUMENTS INCORPORATED with its offices located at 8505 
Forest Lane, Dallas, Texas 75243 ("TI" herein) and IAT AG with offices 
located at Geschaeftschaus Wasserschloss Aarestrasse 17, 5300 
Vogelsang-Turgi, Switzerland ("IAT" herein) have previously entered into July 
18, 1996 Agreement #MSC10850 (the "Agreement" herein) related to licensing of 
TI Products and IAT Products as well as the development of Joint Products 
exchanged between IAT and TI; 

NOW THEREFORE, the parties hereby agree to amend the above referenced 
Agreement by adding the following new language: 

   1. Modify Secton 3.1 in its entirety to read: 

      "3.1 With the exception of the VC Development Software, Reference Design 
      Transfer, Intermode Message Manager, Direct Draw Client Driver-WIN95, 
      and B Channel Network Driver and subject to IAT completing its 
      obligations and granting of licenses to TI as elsewhere provided herein, 
      TI grants to IAT a worldwide, non-transferable, non-assignable, 
      non-exclusive license under TI's copyrights and associated trade secrets 
      solely to use, modify, compile, or otherwise develop as applicable 
      software programs which may be original or derivative with respect to 
      the counterpart TI products, and to make, have made, use, and sublicense 
      use of object code versions of such software programs solely for 
      operation on TI DSP's. TI DSP's are defined to be any TMS320CXX 
      Microprocessor manufactured by Texas Instruments. Except with respect to 
      the Databeam software, which shall be royalty bearing as provided in 
      Section 4 herein, all licenses hereunder shall be fully paid. All the 
      terms and conditions of this license shall be applicable to any 
      modifications of the Licensed Products made pursuant to this Agreement. 
      In the case of the VC Development Software, Internode Message Manager, 
      Direct Draw Client Driver-WIN95 and B Channel Network Driver, all 
      license rights above apply except that such licenses to IAT shall be 
      exclusive." 

   2. The license granted by IAT to TI in Section 3.6, 3.7 and 3.8 shall 
      terminate upon execution of this Amendment No. 1; provided that 
      termination of such license shall not effect the rights of TI's current 
      sublicensees. 

   3. Add to the end of Section 7 the following: 

      "7.4 TI represents and warrants that upon execution of this Amendment 
      No. 1, it will not continue to exercise its current right to license to 
      third parties the VisionPoint 80 printed circuit board design. 

      7.5 IAT represents and warrants that it will provide to TI upon TI's 
      request maintenance and support services for the H.320/H.324 library at 
      a level no less than IAT currently offers to its other customers, and 
      under terms and conditions no less favorable than IAT currently offers 
      to its other customers similarly situated." 

Except as herein above amended, the provisions of the Agreement remain 
unchanged and fully effective. 
                         [continued on the next page] 



                                                         TI/IAT
                                                         Agreement #MSCI10850
                                                         Page 2 of 2
                                                         05/21/97


IN WITNESS WHEREOF, the parties have caused this Amendment No. 1 to be 
executed by their duly authorized representatives as of the date of last 
signature below. 



                                                 
TEXAS INSTRUMENTS INCORPORATED                      IAT 

                                                     
By: /s/ Michael J. Hames                            By: /s/ Dr. Victor Vogt 
   --------------------------------------------     ------------------------- 

Name: Michael J. Hames                              Name: Dr. Victor Vogt 

Title: Vice President, Semiconductor Group          Title: CEO 
                                                     
Date: 6/2/97                                        Date: 5/5/97
     ------------------------------------------     -----------------------