| 摘要 |
PURPOSE:To start loudspeaker communication without key operation by a called party by providing a means for detecting a voice signal inputted to a microphone and setting talking by a loudspeaker communication circuit. CONSTITUTION:When a call comes, a call signal detection circuit 8 detects a call signal and a control circuit 9 controls the loudspeaker communication circuit 7 to send a call tone of a tone ringer from a speaker 3. Moreover, while no tone ringer is operative, a level detection circuit 10 detects whether or not a voice level entering from a microphone 4 exceeds a prescribed value. When the level exceeds the value, the control circuit 9 controls a dialing circuit 6 according to the detection output to return a response signal to close a DC circuit and to control the loudspeaker communication circuit 7 thereby attaining the talking by the speaker 3 and the microphone 4.
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