Abstract: A vehicle user can request emergency or roadside assistance from a response center by activating a button in the vehicle. The global positioning system is used to continuously store the vehicle location. A cellular telephone network is used to contact a response center and transfer a data string via modem containing information to assist the response center in acting on the request. Prior to attempting dialing of the cellular transceiver, a command or set of commands places the cellular transceiver into an unrestricted operating mode to provide the greatest probability of completing a call from the vehicle to the response center and from the response center to the vehicle.

Abstract: A vehicle user can request emergency or roadside assistance from a response center by activating a button in the vehicle. The global positioning system is used to continuously store the vehicle location. A cellular telephone network is used to contact a response center and transfer a data string via modem containing information to assist the response center in acting on the request. Predetermined information concerning system operation is stored in a non-volatile memory during an activation for diagnostic purposes. Data is written in two groups at respective times during an activation, and a status flag indicates whether both groups were successfully written to memory.