Int 7F Fn 10  - Alloy Ntnx, Mw386 - Channel Control - Open Channel         [N]

   AH = 10h
   CL = 00h
   AL = channel number
   DX:DI -> channel buffer

Return: AL = status (00h-03h,0Dh) (see below)

Note:  may not be invoked from within a hardware interrupt handler

See Also: AH=10h/CL=01h,AH=10h/CL=04h,AH=14h/CL=02h

Values for status:
 00h   successful
 01h   busy
 02h   channel range error (not 00h-3Fh)
 03h   invalid subfunction
 0Ah   channel not open
 0Ch   channel already locked
 0Dh   unable to open