Patent 7539804 was granted and assigned to Denso on May, 2009 by the United States Patent and Trademark Office.
An airbag ECU includes a communication bus connection circuit for connecting communication buses to communication circuits. A central control circuit connects some of the communication buses to the communication circuits with the communication bus connection circuit and sets addresses for some of slave sensor devices. When those addresses are set, the other communication buses are connected to the communication circuits by the communication bus connection circuit, and addresses for the other slave sensor devices are set. Thus, a circuit can be made simpler without any influence on address setting, thus reducing cost and size of an airbag apparatus.