Method of controlling communications in a cellular radiotelephone system

摘要

A cellular system employs a subaudible signalling control protocol. The protocol includes transmitting supervisory related signals between the radiotelephone and one of the cell sites at a first subaudible digital bit rate, and transmitting data messages between the radiotelephone and said one of the cell sites at a second subaudible digital bit rate. Additionally, the system employs specific protocols involving alert, hand-off and call disconnect which accommodate the subaudible signalling, yet provide significant integrity and reliability advantages over previously known protocols.