Format of CAS external data block:
Offset	Size	Description	)
 00h	BYTE	CAS major version
 01h	BYTE	CAS minor version
 02h 68 BYTEs	ASCIZ path to directory containing CAS software, ends in slash
 46h 13 BYTEs	ASCIZ name of current phonebook (in CAS directory)
 53h 13 BYTEs	ASCIZ name of current logo file (in CAS directory)
 60h 32 BYTEs	ASCIZ default sender name
 80h 21 BYTEs	ASCIZ CCITT identification of fax device
 95h 107 BYTEs	reserved