Int 14 Fn 21  - PC-mos/386 V5.01 $serial.sys V5.04 - Output Character, Wi  [S]

   AH = 21h
   AL = char to send
   DX = port number
   SI = timeout in timer ticks (0000h = default)
Program: PC-MOS/386 v5.01 is a multitasking, multiuser MS-DOS 5.0-compatible
     operating system by The Software Link, Inc.

See Also: AH=01h,AH=0Eh"PC/MOS",AH=22h"PC-MOS"