Patent ID: 7610135

Claim:
An apparatus for transmitting data in an airbag activation system mounted on a vehicle, the apparatus comprising: a communication channel having a predetermined transmission band for digital data; a plurality of sensor units mutually communicably connected via the communication channel, each sensor unit sensing a state of the vehicle, producing data indicative of the sensed state of the vehicle into a set of digital data including actually sensed data of a predetermined bit length, the actually sensed data corresponding to the sensed state of the vehicle, and outputting the set of digital data to the communication channel at predetermined transmission intervals, either the bit length of the actually sensed data or a frequency of transmission of the digital data being changed depending on the sensed state of the vehicle and the set of digital data being outputted successively from the sensor units; and a processing unit that successively receives the digital data from each sensor unit via the communication channel, wherein each of the sensor units is provided with a sensor sensing, as the state of the vehicle, an impact load to be applied to the vehicle and each of the sensor units is configured to produce information representing an increase in the bit length of the actually sensed data or an increase in the transmission frequency in cases where the sensed impact load has a large amplitude involving changes in predetermined high bits of the actually sensed data and information representing a decrease in the bit length of the actually sensed data or a decrease in the transmission frequency in cases where the sensed impact load has a small amplitude involving no changes in predetermined high bits of the actually sensed data.