METHOD FOR A SESSION INITIATION PROTOCOL PUSH-TO-TALK TERMINAL TO INDICATE ANSWER OPERATING MODE TO AN INTERNET PROTOCOL PUSH-TO-TALK NETWORK SERVER

摘要

A push-to-talk communication device (20, 4, 5, 6) including an operating answer mode (22) indicates that operating answer mode to a Session Initiation Protocol / Internet Protocol based push-to-talk network server (24, 2) .The method includes employing as the operating answer mode of the push-to-talk communication device one of an automatic-answer mode (28), an always-automatic-answer mode (29) and a manual-answer mode (30). A Session Initiation Protocol / Internet Protocol core network (34) is employed including the Session Initiation Protocol / Internet Protocol based push-to-talk network server. The operating answer mode is indicated in a Session Initiation Protocol message (40) from the push-to-talk communication device to the Session Initiation Protocol / Internet Protocol push-to-talk network server over the Session Initiation Protocol / Internet Protocol core network