Apple FAX Modem Work With Any Standard FAX

Apple's FAX modem, operating over normal telephone lines, will transmit
or receive documents with any FAX device that supports the CCITT Group 3
FAX standard.

All modems take digital information and modulate it into analog form when
sending a file. The information is then demodulated into digital form when
the file is received.

The CCITT Group 3 standard is in use by the majority of installed FAX
devices.