PURPOSE: To simplify the equipment construction of a system by converting the video signal from a TV camera device to a required high frequency signal and mixing it on a community television line to distribute it.

CONSTITUTION: When a visitor inputs the house number of his objective house with a key pad 101 of an entrance part 1 and an adapter 301 of the house and the entrance part 1 are connected by a telephone line, a branch adapter 303 converts the high frequency signal to the signal frequency of a prescribed idle channel of TV broadcast to output it to a TV receiver 304. The adapter 301 indicates the channel switching to the receiver 304 to switch the channel to the idle channel, and the video signal from the branch adapter part 303 is projected. A receiver sees the picture on the receiver 304 to decide reception of the visitor. Thus, it is unnecessary to individually wire coaxial cables, and the equipment construction of the system is simplified.