Abstract: An automobile integrated wiring system has a central control unit adapted to act upon operator control instructions. The central control unit is arranged to provide output signals over a transmission path to a plurality of controllable peripheral devices each of the peripheral devices being arranged to perform a control function of the automobile. At least one of the peripheral devices includes detecting means for detecting an abnormality in the central control unit and means adapted to accept operator control instructions over the transmission path when the central control unit is detected to have an abnormality so that an appliance associated with the peripheral device may be operated by said peripheral device in the absence of instruction from the central control unit.

Abstract: In an automobile multiplex data communication system (1000), a fail-safe function is established without providing a specific function switch. The automobile multiplex data communication system (1000) includes: transmission means (3:11:101:901) for transmitting operation data about a plurality of operation units (2a:106:204:704) provided with a plurality of terminal units (1a:202:602:902) corresponding thereto, which are required to operate an automobile; drive means (4:420) for driving a relevant terminal unit (1a:202:602:902) in response to said operation data; detecting means (5:410) for detecting an extraordinary state concerning transmission/reception operations of said operation data to produce an extraordinary-state detection signal; and control means (6:12) for independently controlling the operation of said relevant terminal unit (1a:202:602:902) by AND-gating said extraordinary-state detection signal and each of operation outputs derived from said operation units.

Abstract: In a data transmission system with such a construction that a plurality of terminal units are connected to a first and a second loop transmission line for transmitting messages in a first direction and in a second direction which is opposite to said first direction, respectively, through a pair of transmission control units (the one unit being connected to said first loop transmission line with the other unit being connected to said second loop transmission line), each transmission control unit sends a check message sequentially in order to check the state of a minor loop which connects two adjacent pairs of transmission control units. This check message has a data field, in which an initial value is set at the sending time. The value of this data field is incremented by one in each transmission control unit through which the message passes to make a round through the minor loop.