The Project54 common interface for the intelligent transportation systems data bus

Police cruisers have a variety of aftermarket equipment such as lights, sirens, radar units, radios, etc. Most police aftermarket equipment was not designed with integration in mind. In order to allow the integration of electronic equipment in police cruisers a common interface for connecting aftermarket car electronics to an intelligent transportation systems data bus (LOB) was designed and implemented. The interface hardware uses Version 2.0B of the control area network (CAN) protocol as the method of hi-directional data transmission on the IDB. As a means to connect the aftermarket devices to the IDB the interface has two options. The first type of connection offered is a serial port that uses standard RS-232 signaling. The second type of connection is a port that offers five parallel TTL level signals that can be used for a variety of applications including switching The common interface is currently being installed in several New Hampshire State police cruisers. Initial tests show the system to be reliable.