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. A facsimile machine start button is then operated to start the facsimile machine which scans documents provided therein and transmits the scanned data in a conventional facsimile transmission format or activate the PC to transmit a fax in conventional facsimile transmission format to utilize the facsimile machine as a printer. The PC may be equipped with a suitable software program for converting non-graphic, i.e. such as word-type information into a binary format suitable for use in word processing applications and may store the data in a memory for subsequent use. An automatic circuit may be provided to initiate a scanning or printing mode responsive to receipt of a unique number received from either the facsimile machine or the PC, thus eliminating the need for switches.