The Global System for Mobile communications (GSM) is the standard used for most mobile phone communications and the General Packet Radio Service (GPRS) is a data communications service available to GSM users.

GPRS is used by many automotive telematics systems to transfer data between vehicles out on the road and central control/monitoring stations. This is why each in-vehicle telematics device using GPRS must have a SIM card provided by a mobile phone service provider.

GPS
The Global Positioning System (GPS) uses a constellation of 24 satellites to transmit microwave timing signals to earth. These enable GPS receivers to determine their location, speed, direction, and the time.

Vehicle telematic devices are equipped with a GPS receiver in order to relay position information via the GPRS network back to a central control/monitoring station. Usually, telematics control/monitoring software allows the near real-time position of vehicles to be displayed graphically on street-level digital maps.

Telematics
Telematics means the integrated use of telecommunications and informatics to send and receive information via communications networks (such as GPRS.

Automotive telematic information includes information from switches and sensors connected to an in-vehicle telematics device or it could be detailed information gleaned from the vehicle’s own Controller Area Network (CAN).