| 摘要 |
PROBLEM TO BE SOLVED: To omit the manual termination setting work of an extension monitor master unit at the time of construction. SOLUTION: In a video interphone system, an entrance slave unit with a camera is successively and serially connected to a monitor master unit and a plurality of the extension monitor master units 300 and 400, one of the monitor master unit and the extension monitor master units is called from the entrance slave unit with the camera and communication is performed with the entrance slave unit with the camera while viewing video images from the entrance slave unit with the camera on a called side. The extension monitor master units are provided with terminating circuits 310 and 410 provided on the respective serially connected extension monitor master units and photocouplers 302 and 402 for detecting a DC current flowing to the present sets, deciding whether or not the present sets are a final end and turning the terminating circuits on and off in accordance with the decision. COPYRIGHT: (C)2004,JPO
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