Abstract: Apparatus for interfacing a conventional facsimile machine with a PC enabling the use of the facsimile machine as a scanner or printer. A first switch assembly selectively couples the PC modem and facsimile machine either to independent telephone lines in a normal mode or to one another in a scan print mode. A manually operated switch assembly is depressed for a brief interval sufficient to activate a ringing circuit which converts DC power from a small battery source to a 20 Hz sine wave of 90 volt amplitude and applies the sine wave signal to the PC to cause the PC or facsimile to enter into a scan or print mode, respectively. The manually operable switch is then released to apply a constant current to the facsimile machine to simulate an off-hook condition.