Abstract: An automatic input/output terminal varying circuit comprising an input/output terminal section including a plurality of input/output terminals for inputting signals from external signal sources and outputting signals to external systems, an input signal selection section for selecting one of the signals inputted through the input/output terminal section and a television signal in response to select data from a microcomputer and outputting the selected signal to a signal processor, and a plurality of output signal selection section for outputting the selected signal from the input signal selection section to ones of the input/output terminals of the input/output terminal section other than one of the input/output terminals of the input/output terminal section through which the selected signal is inputted, in response to the select data from the microcomputer.

Abstract: An audio/video signals input terminal circuit comprising an input terminal section having a plurality of input terminals, a select control signal generating circuit for detecting the presence of a synchronous signal at the input terminals of the input terminal section and generating first and second select control signals in accordance with the detected result, an audio/video input switching circuit having a plurality of input port sets and a plurality of output ports, the audio/video input switching circuit selecting one of the input port sets inputting a video signal in response to the first and second select control signals, outputting the video signal inputted through the selected input port set through the corresponding output port and outputting right and left audio signals inputted through the other input port sets through the corresponding output ports, respectively, and an audio input switching circuit having a pair of input port sets and a pair of output ports, the audio input switching circuit sele