Patent ID: 7539804

Claim:
A communication apparatus comprising: a master device having a plurality of communication circuits for transmitting and receiving serial data; a plurality of communication buses over which serial data are transmitted; and a plurality of slave devices daisy-chain-connected to the communication circuits through respective ones of the communication buses for transmitting and receiving serial data to and from the communication circuits, wherein the communication circuits set addresses for the slave devices through the plurality of communication buses at the time of initial setting, and thereafter transmit and receive serial data to and from the plurality of slave devices using the set addresses, wherein the master device further has a communication bus connecting circuit for sequentially connecting the plurality of communication buses to the communication circuits; the plurality of slave devices include a right group of sensors and a left group of sensors for detecting information on a collision of a vehicle at a right side and a left side of the vehicle respectively; the right group of sensors are connected to one of the communication circuits and the left group of sensors are connected to another one of the communication circuits; and the master device is an electronic controller for controlling a passenger protection unit in the vehicle based on information on a collision of the vehicle detected by the plurality of slave devices.