Int D4 Fn 23  - Pc-mos/386 V5.01 - Change Terminal Driver                  [O]

   AH = 23h
   BX = task ID (FFFFh for current task)
   DS:SI -> entry point of the new Device Driver Terminal

Return: CF clear if successful
   CF set on error
       AX = error code (see #1366 at INT 21/AH=59h/BX=0000h)