INT 14 - MultiDOS Plus - SET MONITOR MODE
AH = 24h
AL = port status storage
00h single status for entire receive buffer
01h separate status kept for each byte in receive buffer
DX = port number
Return: AH = status
00h successful
3Ah invalid status storage specified
41h no such port
64h monitor mode already active
Note:   in monitor mode, MultiDOS redirects all BIOS video output to a serial
port
SeeAlso: AH=25h

See also: 1420

1424 - MultiDOS Plus - SET MONITOR MODE