Int 15 Fn 05 - Multidos Plus - Check Mailbox [T] AH = 05h AL = mailbox number (00h-3Fh) Return: AH = status 00h successful DX = length of first message in queue, 0000h if no message 02h invalid mailbox number See Also: AH=04h"MultiDOS",AH=06h"MultiDOS"