| 摘要 |
PURPOSE:To prevent malfunction and rise inoperation of transmission start by using the output of the end of a call signal detecting circuit so as to start the transmission section for a prescribed time, and operating a microphone input sensing circuit at the same time thereby continuing the start of transmission. CONSTITUTION:A signal of a prescribed time is generated by the end of call detection section 4 and a one-shot multivibrator 5 at the end of reception, a transmission reception switching section 2 is switched via an OR circuit 7, a transmission section 3 is operated to attain the transmission state. In such a case, when no signal exists in a microphone 9, the state is restored in the receiving state, and when the signal exists in the microphone 9, a microphone input sensing section 8 detects the presence of voice, the transmission state is continued via the OR circuit 7, the transmission section 3 modulates the signal by the audio signal and the result is sent, and if the voice of the microphone 9 is interrupted, the state is restored to the transmission state. Thus, the talking with the opposite station is attained without operating a transmission start switch 10 of the microphone and the similar operation is attained by one operation without consecutive operation of the transmission start switch 10 of the microphone. Thus, the rise is ensured and malfunction is eliminated.
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