System for providing a simultaneous data and voice channel within a single channel of a portable cellular telephone to provide position-enhanced cellular services (PECS)

摘要

An accessory device for portable telephones which provides simultaneous functionality of a hands-free accessory device and a data-in-voice modem enabling a portable telephone to be used in a vehicle such that the driver can be engaged in a hands-free conversation at the same time as data (such as GPS position information) is being sent over the same cellular voice channel.