Abstract: An automotive information system has a main unit including a CPU and component units connected to the main unit through a universal serial BUS (USB), such as a car audio system including a CD-ROM auto-changer, a security control system, and a telephone system. At least one of the USB-connected component device, e.g., the security control system and/or the telephone system, has a detecting unit that detects occurrence of an event such as illegal approach to the automobile or receipt of telephone call. The USB-connected component device also has a start signal transmitting unit that transmits a start signal to the main unit when occurrence of the event is detected by the detecting unit. The main unit has a start signal receiving unit and a power control unit that serves turn on the power supply to the main unit in response to the start signal received by the start signal receiving unit.

Abstract: An automotive information system has a main unit including a CPU and component units connected to the main unit through a universal serial BUS (USB), such as a car audio system including a CD-ROM auto-changer, a security control system, and a telephone system. At least one of the USB-connected component device, e.g., the security control system and/or the telephone system, has a detecting unit that detects occurrence of an event such as illegal approach to the automobile or receipt of telephone call. The USB-connected component device also has a start signal transmitting unit that transmits a start signal to the main unit when occurrence of the event is detected by the detecting unit. The main unit has a start signal receiving unit and a power control unit that serves turn on the power supply to the main unit in response to the start signal received by the start signal receiving unit.

Abstract: A convolver optimum bias circuit is disclosed, in which a DC bias voltage representing a phase difference between a signal corresponding to the output of an oscillator given to the gate electrode of the convolver and the output of a convolver phase circuit is applied to the gate electrode of the convolver.

Abstract: An optical signal detecting circuit is configured so that its detection sensitivity for detecting an optical signal received by a light receiving element is set by selecting desired values of fixed current sources I and I' and a desired current division ratio of independent PNP multicollector transistors Q1 and Q2 and so that its optical signal detecting hysteresis range is set by selecting a desired current ratio of I and I' or a desired current division ratio of the independent PNP multicollector transistors Q1 and Q2.