Int 14 Fn 11  - Digiboard Digichannel Pc/x* - Clear Transmit Buffer        [S]

   AH = 11h
   DX = port number (00h-03h) (04h-43h for XAPCM232.SYS)

Return: AH = status
       00h successful
       FFh error

See Also: AH=09h"Digiboard",AH=10h"Digiboard"