PURPOSE: To perform call service or data communication according to the kind of an indication signal from an origination side, by allowing the call service or data communication on the basis of the signal indication from the origination side.

CONSTITUTION: When a multifunction telephone set 2' originates and the telephone number of a multifunction telephone set 2 is dialed, a switching network 3 sends an audible ringing tone to the telephone set 2. The circuit correspondence part 4 of the telephone set 2 detects the ringing tone to close a circuit and then monitors the call indication from the circuit side for only a specific time T1 while sending an incoming answer signal from a signal transmission and reception part 7 to the circuit side. The telephone set 2 rings the bell of a bell control part 8 the specific time T1 later and also controls the correspondence parts 4 to connect the circuit side to a voice transmission part 5, sending a voice message from the transmission part 5 to the circuit side. When an operator on the side of the telephone set 2 lifts the handset of a transmitter 6 after the bell sounds, the telephone set 2' detects that to enable call service. If a data communication signal is received within the time T1, the transmission and reception part 7 performs the data communication.