INT 7F - Alloy NTNX, MW386 -  SET RECEIVE ISR
        AH = 14h
        CL = 00h
        DX:DI -> application FAR receive service routine (see below)
Return: AL = status
            00h successful
            01h busy
            02h channel range error (not 00h-3Fh)
            03h invalid subfunction
SeeAlso: AH=14h/CL=03h

Service routine called with:
        DH = sender ID
        DL = channel with datagram
        interrupts disabled
Return: AL = response code
            00h leave buffer locked, set channel status, and repeat call later
            01h release channel buffer
            02h change buffer pointer to DX:DI
        AH,CX,DX,DI,SI may be destroyed