PURPOSE: To allow an incoming call tone to ring only for an object terminal equipment by allowing the caller to use an extension number by PB signal thereby designating an extension number after the reply to the incoming call.

CONSTITUTION: When an incoming call signal is inputted from a telephone line connecting to a line connection section 11, an incoming call detection section 2 informs it to a control section 7 that the incoming call signal is inputted. The control section 7 counts the period of the incoming call signal and lets a line closing section 2 when the count reaches a prescribed number to close the telephone line. Then the control section 7 allows an audio synthesis section 5 to utter an audio signal representing the designation of an extension number in a PB signal by the caller and the signal is sent to the telephone line via a 2/4-wire conversion section 10. When the caller sends the PB signal, the PB signal is analyzed by a PB signal reception section 4 via the 2/4-wire conversion section 10 from the telephone line and the received number is informed to the control section 7. The control section 7 controls a radio signal transmission reception section 8 to allow a radio slave set 20-N having an extension number corresponding to data from a PB signal reception section 4 to perform an incoming call display and to control a radio signal transmission reception section 8 and to set a radio link, to which the data for incoming call display are sent.