| 摘要 |
PROBLEM TO BE SOLVED: To provide a video interphone system for multiple dwelling house capable of transmitting multiplexed voice, control and video signals on the same line in order to realize wiring / installation work saving through reduction in number of wire pairs. SOLUTION: A shared part apparatus 10, a branch 30, and an interphone 20 are interconnected by a pair of shared transmission lines A, a video signal, voice signal, and a control signal are frequency-multiplexed on the shared transmission lines A, the branch 30, connected between the shared transmission lines A being a trunk line before branching and the shared transmission lines A after branching, comprises: a series circuit including a video signal demultiplexer section 303, a video signal branch transformer 301, and a video signal demultiplexer section 303; and a parallel circuit including a video signal demultiplexer section 302 and a control signal demultiplexer section 304, once demultiplexes therein the video signal, the voice signal, and the control signal and then applies frequency multiplexing to the signals. COPYRIGHT: (C)2004,JPO&NCIPI
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