A method of communicating with a telematics-equipped vehicle includes receiving a circuit-switched telephone call at a central facility from a telematics-equipped vehicle via a wireless carrier system that is in local communication with the telematics-equipped vehicle; determining during the circuit-switched telephone call that a separate packet-data communication session between the telematics-equipped vehicle and the central facility is desired; identifying the wireless carrier system that is in local communication with the telematics-equipped vehicle; querying the identified wireless carrier system from the central facility to determine whether the telematics-equipped vehicle is authorized to establish a packet-data communication session using the identified wireless carrier system; if so, obtaining an Internet protocol (IP) address from the identified wireless carrier system; and commencing the exchange of data between the telematics-equipped vehicle and the central facility using the obtained IP address.