| 摘要 |
PURPOSE:To attain a transmitter-receiver possible for mutual talking between plural devices by providing two transmitter-receiver possible for transmission/reception automatic changeover and activating the transmitter-receiver not in the reception state as a transmitter when a voice signal is inputted. CONSTITUTION:A voice signal applied to an adder 16 is fed to an amplifier 17, and amplified and fed to a speaker 18. When a handset is hooked off, a control signal is fed to a control signal input terminal 6. A control circuit 7 receiving the control signal controls the transceiver 5 not in the reception state to the transmission side and changes over a signal changeover switch 3. Then a voice signal from a microphone 1 amplified by the amplifier 2 is fed to the transceiver 5 as a modulation signal. As a result, the carrier (frequency f2) is modulated and outputted by the transceiver 5 supplies with the voice signal. The FM wave (frequency f2) is transmitted to a power line via a transmission transformer 11 through coupling capacitors 13, 14. |
