AST RESEARCH TECHNICAL BULLETIN TB-0134                  11-11-85


                    AST-3780 TROUBLESHOOTING


The intent of this Technical Bulletin is to help the installer of 
AST-3780  isolate  any  problems which may arise.   The  bulletin
will  cover the situations reported most frequently by  users  of 
AST-3780.

PROBLEM
AST-3780  is  activated and the connection to the host  has  been 
established.   The  transmit option is selected from the AST-3780 
software and the modem immediately starts streaming data.

Streaming,  in this context, refers to a constant request-to-send 
coming  from  the  DTE interface,  while  the  DCE  interface  is 
supplying a clear-to-send response, and the transmit data line is 
constantly sending a stream of data.

SOLUTION
There  are only six reasons for this situation to  occur.   Their 
causes and resolutions are listed below in  "most frequently  the
cause" order:

  I.  The cable from the CC-432 card to the modem is missing
      line 15 or 17, or both.

      A.  There is only one accurate way to assure that the lines
          are there, and that is through the use of an OHM meter.

          1.  If an OHM meter is unavailable, make the user 
              remove the hoods from the cable and visually
              inspect both ends.

 II.  The modem is not supplying transmit and receive clocks.

      A.  Check your modem manual to make sure that your modem
          is optioned for internal clocking.

III.  The CC-432 card has Jumpers 2 and 4 enabled instead of
      1 and 3.

 IV.  There is an interrupt conflict within the PC.

      A.  Other BSC cards
      B.  Network cards
      C.  Third party hard disk

  V.  AST-3780 configuration file is selected for a different
      interrupt request line than that selected on the CC-432
      board.

      A.  i.e., software selected for IRQ-2 while the CC-432
          is selected for IRQ-7.

 VI.  The CC-432 board is defective and needs to be returned
      for repair.

      A.  To insure that this is the cause, run the CC-432
          test supplied in the package.