An OBD II (on-board diagnostic) connector is designed for vehicle systems’ check-up. It is compatible with most modern vehicles. Through this connector you can receive data from the on-board computer and other sensors of the vehicle.
GPS equipment manufacturers make the most of these advantages and crafted an OBD tracking device that can be plugged into ODB II connector directly. At this page you can find OBD GPS trackers, compatible with Wialon.