Int 7F Fn 12  - Alloy Ntnx, Mw386 - Acknowledge Datagram                   [N]

   AH = 12h
   AL = channel number being acknowledged
   DI:DX = 32-bit status to return to sender

Return: AL = status (see below)

Note:  also unlocks the channel, allowing the next datagram to be received

See Also: AH=11h,AH=15h/CL=04h

Values for status:
 00h   successful
 01h   busy
 02h   channel range error (not 00h-3Fh)
 03h   invalid subfunction
 0Ah   channel not open
 0Bh   no message in channel
 0Ch   destination slave busy--retry (NTNX)
 0Dh   destination user not active
 0Eh   destination slave not active (NTNX)
 0Fh   destination disabled datagram service