| 摘要 |
PURPOSE:To realize a loudspeaking call and a close call with a common microphone, by providing a gaincontrol means which sets the gain of an amplifier means at a high gain when a handset is positioned in the vicinity of a housing means, and a low gain when it is separated from the means. CONSTITUTION:When the handset 13 is removed from a pad 12, no amplifier AMP7 is operated even when a loudspeaking call control circuit 36 is operated. Also, at this time, a microphone amplifier circuit 33 is set at the low gain, and the close call can be performed automatically if the handset 13 is removed from the pad 12. Adversely, when the handset 13 is housed in the pad 12, the amplifier AMP7 is operated by operating the loudspeaking call control circuit 36. Also, at this time, the microphone amplifier circuit 33 is set at the high gain. Because a power from the pad 12 is supplied to the contact 17 of a power source for the loudspeaking call. In such a way, the loudspeaking call can be realized automatically when the handset 13 is housed in the pad 12.
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