Abstract: An input/output device of audio and video signals routed between a television and auxiliary audio/video appliance includes a switching circuit for switching audio and video signals input to or output from audio jacks and video jacks provided on a user accessible part of the television, and a controller providing a control signal for controlling the switching operation of the switching circuit. The input/output device may advantageously include a light emitting element for indicating the operative state of the switching circuit. The input/output device permits selective input to or output from the television of audio and video signals via a single set of jacks provided on the front of the television while permitting the user to easily confirm the operating state of the device.

Abstract: A method for BICMOS devices is disclosed, wherein an emitter and a base of a vertical PNP transistor are self-aligned, an extrinsic base is formed by adapting a base electrode polysilicon layer as a diffusion source, and the base electrode and an intrinsic base are coupled by diffusion of N type impurities adapting the N.sup.+ polysilicon as a diffusion source, so that the manufacturing process is simplified and the resistance of the extrinsic base is reduced.