New system is a boost for car safety

Companies claim innovation will allow easier installation of multiple safety features on cars

A communication system developed by TRW and Motorola could allow easier installation of multiple, interconnected safety devices in cars.

They say the Distributed Systems Interface allows carmakers to add side-impact airbags, seatbelts with built-in airbags, pre-tensioners and occupant sensors without redesigning the restraint system. They are trying to encourage its adoption as an industry standard.

`The high growth rate in automotive component safety systems over the next decade will demand re-thinking of the way sensors, actuators and control functions are partitioned and controlled within the vehicle,’ said Thomas J Doyle, vice-president of worldwide operations for TRW Automotive Electronics.

Through its two-wire serial bus, the DSI links remote sensors and actuators to a central electronic control module. The two-wire bus is connected both to sensors and actuators, and provides power and communications. The protocol was chosen to minimise message lengths and reduce message time.

The bus architecture is a master/slave system, with the central control module being the master and remote sensors and actuators acting as slave devices. A new sensor or actuator can be added to the bus without reconfiguring the system design, reducing costs.

The prime market for the DSI, to be available by 2002, is car manufacture. The companies believe DSI use could spread to any application involving distributed intelligent sensors and actuators.

TRW and Motorola are allowing third-party adopters of the standard to access its key technologies without royalties or licensing fees. The DSI bus specification is on: and