INT 2F - Communicating Applications Specification - GET DIAGNOSTICS RESULTS
        AX = CB13h
        DL = 00h
Return: AX = 0040h in progress
           >= 0    passed
           < 0     hardware-dependent failure code (see below)

Intel Connection CoProcessor failure codes:
        bit 3: 9600 bps FAX modem module failed
        bit 2: SDLC chip failed
        bit 1: RAM failed
        bit 0: ROM checksum failed

Intel SatisFAXtion failure codes:
        bit 1: 2400 bps data modem failed
        bit 0: 9600 bps FAX modem failed