Patent ID: 8320914

Claim:
A connection retry method for use by a vehicle telematics unit to establish a wireless telephone connection between the telematics unit and a call center, comprising the steps of: carrying out a primary connection attempt between the telematics unit and the call center using an attached base station, wherein the primary connection attempt includes the steps of: determining if the telematics unit is currently attached to a base station and, if not, executing an idle mode process involving cell reselection, attaching to a reselected base station; and thereafter originating an in-band modem cellular call between the telematics unit and the call center via the attached base station; determining whether the primary connection attempt was successful and, if not, then carrying out a secondary connection attempt in which the telematics unit attempts to connect to the call center via one or more of the public land mobile networks (PLMNs) that have been previously successfully used to place calls by the telematics unit; and determining whether the secondary connection attempt was successful and, if not, then carrying out a tertiary connection attempt in which the telematics unit attempts to connect to the call center via any of a number of available base stations with which the telematics unit is able to communicate.