Abstract: A facsimile interface device for a land-mobile telephone system includes a changeover circuit for connecting and disconnecting a facsimile device with a land-mobile telephone circuit, and a matching circuit for electrically matching the facsimile device to the telephone circuit. The interface device further includes a control circuit for determining based on the position of a mode select switch whether a signal received is for the telephone circuit or the facsimile device, and for controlling the changeover circuit accordingly.