This is an automatic video switch (AVS). With this device you can connect a DVD player, satelite receiver and a game console to your TV without repluging. You can connect 4 video and audio sources to one TV and the AVS will automatically switch to the signal applied last. If only one source is active, the switch turns to that one. There is also one switch signal. It is possible to drive a relay with this output and turn the TV off automatically if no video source is applied. This is the circuit side of the self etched PCB.