US Patent 7561211 Video/audio system

A video/audio system includes a video/audio output unit (head unit) 1 for outputting video information and audio information to a monitor 5 or an audio transmitter 6; a video/audio output unit (external player) 2 which is connected to the video/audio output unit 1 via a common signal line 3 and carries out switching output of external video information and audio information to the monitor 5 or audio transmitter 6; and a remote control unit 4 for selectively operating the video/audio output units 1 and 2 externally. The video/audio output units 1 and 2 operate in at least one of the single and combined circuit modes in response to the signal transmitted through the common signal line 3.