| 摘要 |
PURPOSE:To facilitate grasp of a fault by allowing a center to monitor a video signal at an optional position of a transmission line. CONSTITUTION:A video monitor device A in which video signal return devices B1-Bn that extract a video signal of an outgoing channel corresponding to a designated channel identification data and send the video signal to a prescribed incoming monitor channel are inserted to an optional position of a transmission line of a 2-way CATV system when its own device is designated by an address data and which allows a center to monitor the state of a video signal of a prescribed incoming monitor channel is provided with a channel designation means X1 designating an optional outgoing channel to be monitored, a position designation means X2 designating an optional monitored position of the video signal in a transmission line E, a control data transmission means X3 modulating designated characteristic channel identification data and address data specifying a designated position and sending the result to a prescribed control channel, and a video display means X4 receiving a video signal from the specific monitored channel in the transmission line and displaying visually the video image. |
