| 摘要 |
PURPOSE:To prevent malfunction even when an electric field strength is small by generating a data controlling mutually a telephone set main body and a handset with plural signals at a band other than the frequency band of a talking signal and transmitting the data mutually continuously even during the talking. CONSTITUTION:When an incoming call is fed to a telephone line 6, it is received by a controller 7 via a hybrid circuit 8. When the controller 7 detects the presence of the incoming call to the telephone line 6, an oscillator for generating a data tone is driven, its output is FM-modulated by an FM modulator and transmitted as a radio wave to the handset 1. The radio wave is received by an antenna of the handset 1, demodulated by a demodulation circuit 15 and supplied to a controller 2 via band pass filters 17, 18. Thus, signal confirming the reception is outputted from oscillators 20, 21 for generating data tone, FM- modulated and transmitted to the telephone set main body 5. When the telephone set main body 5 receives it, the line is acquired to form a state possible for talking. |
