)
Values for CAS error code:
  (AH = class, AL = subcode, value passed back is 2's complement)
  Class 00h	--- FAX warnings
	Subcode 00h	no error
		02h	bad scanline count
		03h	page sent with errors, could not retransmit
		04h	received data lost
		05h	invalid or missing logo file
		06h	filename does not match nonstandard format (NSF) header
		07h	file size does not match NSF header
  Class 01h	--- DOS warnings (data was sent)
	Subcode 01h	invalid function
		05h	access denied
		06h	invalid handle
		others	see #01680 at INT 21/AH=59h/BX=0000h
  Class 02h	--- fatal errors (data not sent)
	Subcode 00h	multiplex handler failed
		01h	unknown command
		02h	bad event handle
		03h	FIND NEXT attempted before FIND FIRST
		04h	no more events
		07h	invalid queue type
		08h	bad control file
		09h	communication board busy
		0Ah	invalid command parameter
		0Bh	can't uninstall resident code
		0Ch	file exists
		80h	unknown task type
		81h	bad phone number
		82h	bad .PCX file header
		83h	unexpected EOF
		84h	unexpected disconnect
		85h	too many dialing retries
		86h	no file specified for send
		87h	communication board timeout
		88h	received too many pages (>1023) of data
		89h	manual connect initiated too long ago
		8Ah	hardware command set error
		8Bh	bad NonStandard Format (NSF) header file
  Class 03h	--- fatal DOS errors
	Subcode 02h	file not found
		03h	path not found
		others	see #01680 at INT 21/AH=59h/BX=0000h
  Class 04h	--- FAX errors
	Subcode 01h	remote unit not Group 3 compatible
		02h	remote unit did not send capabilities
		03h	other FAX machine incompatible
		04h	other FAX incapable of file transfers
		05h	exceeded retrain or FAX resend limit
		06h	line noise or failure to agree on bit rate
		07h	remote disconnected after receiving data
		08h	no response from remote after sending data
		09h	remote's capabilities incompatible
		0Ah	no dial tone (v1.2+)
		0Bh	invalid response from remote unit after sending data
		0Dh	phone line dead or remote unit disconnected
		0Eh	timeout while waiting for secondary dial tone (v1.2+)
		11h	invalid command from remote after receiving data
		15h	tried to receive from incompatible hardware
		5Ch	received data overflowed input buffer
		5Dh	remote unexpectedly stopped sending data
		5Eh	other FAX machine jammed (no data sent)
		5Fh	remote took too long to send fax scan line
		63h	can't get through to remote unit
		64h	user canceled event
  Class 05h	--- application-specific (v1.2+)
  ---Intel FAXPOP.EXE
	Subcode 00h	tried to send while in graphics mode
		01h	insufficient disk space
		02h	internal buffer overflow
  Class 06h	--- CAS implementation-specific (v1.2+)