| 摘要 |
PROBLEM TO BE SOLVED: To provide an amplifying interphone system in which simultaneous conversation can be ensured during double talks, without causing howling through reaction with the ambient noise. SOLUTION: An amplifying interphone terminal 1-1 conducts hands-free conversation by means of a speaker 6-1 and a microphone 7-1 and comprises a voice switch 10-1 for comparing a reception voice signal with a transmission voice signal and attenuating the transmission voice signal during reception and attenuating the reception voice signal during transmission; a level-detecting section 9-1 for determining the magnitude of the transmission voice signal outputted from the voice switch 10-1 according to a preset threshold and outputting the results; and a first switching section 11-1 and a second switching section 12-1 for switching the reception voice signal from a codec 4-1 to the voice switch 10-1 side, when the level detecting section 9-1 is determined as being small, and switching the reception voice signal from the codec 4-1 to a side that does not pass the voice switch 10-1, when the level detecting section 9-1 is determined as being large. COPYRIGHT: (C)2007,JPO&INPIT
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