| 摘要 |
PROBLEM TO BE SOLVED: To provide a visitor call system capable of improving a speech quality considering the noise environment of a place where a lobby interphone is installed. SOLUTION: This visitor call system performs communication between a lobby interphone 4 installed in the public entrance or the like of a multiple dwelling house and a household information panel (base unit 1) provided in each house and the lobby interphone 4 gathers the surrounding noises. When the value of these surrounding noises is low, the volume of a speaker sound output of a speaker 4c from the lobby interphone 4 is reduced.
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