CIRCUIT FOR SWITCHING TRANSMISSION DIRECTION OF VIDEO SIGNAL, VIDEO IMAGE CONTROLLER, DEVICE FOR SWITCHING TRANSMISSION DIRECTION OF SIGNAL FOR VIDEO IMAGE CONTROLLER, AND COOPERATIVE TRANSMISSION CONTROL SYSTEM OF VIDEO SIGNAL

摘要

PROBLEM TO BE SOLVED: To reduce the cost and size of a circuit for switching the transmission direction of video signal being incorporated in a two household cooperative television interphone without using a relay.;SOLUTION: The circuit for switching the transmission direction of video signal comprises an uplink/downlink video signal amplifier circuit arranged to connect a first signal amplifier for amplifying an uplink video signal being output from a video controller through a transmission line with a second signal amplifier for amplifying an downlink video signal being input to the video controller through a transmission line such that respective input terminals are connected with respective output terminals, and a power supply control circuit having first and second active elements for conducting power supply to the first and second signal amplifiers wherein the first and second active elements are turned on/off by the video controller to pass uplink or downlink video signals selectively.;COPYRIGHT: (C)2007,JPO&INPIT