A facsimile machine which is coupled to a telephone line and a telephone set, where the facsimile machine connects the telephone set to the telephone line in a telephone mode and disconnects the telephone set from the telephone line in a facsimile mode so as to use the telephone line as a communication line for a facsimile communication, and the facsimile machine is connectable to a communication equipment via an interface unit which is designed exclusively for the communication equipment. The facsimile machine includes a single connector including signal lines for receiving and transmitting signals for coupling the facsimile machine to the interface unit, a single switch coupled to the connector for arbitrarily selecting the communication line to the telephone line in a first mode and to the communication equipment in a second mode, and a communication part for making a facsimile communication using the communication line which is selected by the switch.