| 摘要 |
PURPOSE:To stop optionally the loudspeaking of a telephone receiving voice when the telephone receiving voice is not to be heard around by being equipped with a means to connect freely detachably an earphone to a telephone receiving line and being equipped with a switch to separate a speaker at the time of loading the earphone. CONSTITUTION:When an earphone 11 is loaded and a calling is executed, a telephone receiving voice signal amplified through an antisidetone circuit 1 by an amplifier 2 is outputted to the earphone 11 and a voice signal is generated. At such a time, the voice generated from the earphone 11 will not generate an acoustic linking with a microphone 10 by a case oscillation or a space communication, and therefore, a howling is not generated. Further, while the earphone 11 is connected, a telephone receiving voice signal to a voice switch circuit 12 is not inputted by a switch SW, and therefore, a telephone transmitting voice signal is always sent to the opponent side, simultaneously, the telephone receiving signal can be always telephone-received by the earphone 11 and a simultaneous calling can be executed. At such a time, since the voice switch circuit 12 comes to be the same condition as the condition in which the action is not executed, the inconvenience that the circuit is cut by the word head and the word center of a telephone transmitting voice is eliminated.
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