| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an intercom system including compact and low-cost intercom master units provided for each family of a two-family house. Ž<P>SOLUTION: Each of the intercom master units 1 for respective families A1, A2 in the intercom system has: a slave unit connection terminal T1 connected to an intercom slave unit 3 and a camera slave unit 4 ; a submaster unit connection terminal T2 connected to intercom submaster units 2a-2n and the intercom master unit 1 of the other family; a video modulation and demodulation circuit 13 for demodulating a video signal input via the respective connection terminals T1, T2 for displaying on a monitor 12; and a master unit/submaster unit switching circuit 18 for changing the operation mode of the intercom master unit 1 to a master unit mode for allowing the video modulation and demodulation circuit 13 and a submaster unit connection terminal T2 to output the video signal input from the slave units (the intercom slave unit 3 and the camera slave unit 4) of the same family via a slave unit connection terminal T1, or a submaster unit mode for allowing the video modulation and demodulation circuit 13 to output the video signal input from slave units of the other family via the submaster unit connection terminal T2. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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