INT 21 - DOS 3.1+ network - SET REDIRECTION MODE
        AX = 5F01h
        BL = redirection type
            03h printer
            04h disk drive
        BH = redirection state
            00h off
            01h on
Return: CF set on error
            AX = error code (see AH=59h)
        CF clear if successful
Notes:  when redirection is off, the local device (if any) rather than the
          remote device is used
        calls INT 2F/AX=111Eh with AX on top of the stack
SeeAlso: INT 2F/AX=111Eh