PURPOSE: To make a call from a PB telephone set possible to request by suggesting switching to a telephone set with a request from a calling subscriber or interrupting sound response to shorten the call time.

CONSTITUTION: When a ringer signal is inputted from an exchange to a line 1 by key-in from a push-button PB in the calling side, an sound signal or a CED signal is generated. When the transmission is requested by key-in from the PB, a PB signal is inputted to a control circuit 6 by a PB detector 10. If the input signal coincides with the call request, the control circuit 6 controls a timer 9 to terminate the sound transmission from a sound generating source 8. Hereafter, normal facsimile procedures are executed. When the input signal coincides with the call request, the timer 9 is controlled to stop sound generation, and a buzzer 11 is sounded to report it. The operator depresses a telephone calling button to switch a relay contact 2, and the call is made possible.