Int 14 Fn 01  - Serial - Write Character To Port                           [S]

   AH = 01h
   AL = character to write
   DX = port number (00h-03h) (04h-43h for Digiboard XAPCM232.SYS)

Return: AH bit 7 clear if successful
   AH bit 7 set on error
   AH bits 6-0 = port status (see #0230)

Notes: various network and serial-port drivers support the standard BIOS
     functions with interrupt-driven I/O instead of the BIOS's polled I/O
   the 04/08/93 Compaq system ROM uses only the low two bits of DX

See Also: AH=02h,AH=0Bh"FOSSIL",AX=8000h"ARTICOM",AH=89h,MEM 0040h:007Ch