Adapter for use with vehicle-mounted electronics

An adapter for use with vehicle-mounted electronics, comprising an adapter body including:

• an input section provided with at least one main input terminal to which a video signal or audio signal is supplied and at least one secondary input terminal to which a video signal or audio signal is supplied;
• an output section provided with an output terminal from which a video signal or audio signal is delivered;
• a switching element switching an output signal delivered from the input section between the main input terminal side and the secondary input terminal side;
• and
• a control section controlling the switching element, wherein the control section includes a detector which detects a signal supplied to the secondary input terminal side, and the control section controls the switching element based on signal detection by the detector so that the output signal delivered from the input section is only switched from the main input terminal side to the secondary input terminal side when a signal is detected front said secondary input terminal side.