| 摘要 |
PURPOSE:To obtain a loudspeaker telephone set making a talking possible during a work by adding an incoming detection circuit, a switching device and its control circuit to a loudspeaker telephone set. CONSTITUTION:When an incoming signal comes to a terminal 1, an incoming detection circuit 2 detects it and gives it to a control circuit 10. The control circuit 10 controls a switching device 4 in the open state to be closed so as to connect a telephone circuit 5 to a telephone line. As a result, a voice fed to a microphone 6 is sent to the telephone line as a transmission signal and the reception signal from the telephone line is fed to a speaker 7 at the same time to form talking state. When the talking is finished, a switch 9 is closed by the depression of an operation button to cause the control circuit 10 to open the device 4 and the system is restored to the restoring state. when the depression of the operation button is stopped, the switch 9 is opened and the system restores in the standby state for the next incoming call.
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