Patent ID: 8599834

Claim:
A method for providing a manual ring-down communication line using Session Initiation Protocol (SIP), comprising the steps of: transmitting, by a session establisher SIP user agent to a second SIP user agent over an Internet Protocol (IP) network, an INVITE message; receiving, by the session establisher SIP user agent from the second SIP user agent, an acknowledgment message transmitted in response to the INVITE message, thereby establishing a private line SIP session, wherein the private line SIP session provides a manual ring-down communication line; re-establishing, by the session establisher SIP user agent, the private line SIP session after a session failure; determining, by the session establisher SIP user agent, that a signal key associated with a first communication device has been selected; transmitting, by the session establisher SIP user agent to the second SIP user agent over the IP network, a start event message to cause a second communication device to activate an alert; determining, by the session establisher SIP user agent, that the signal key associated with the first communication device has been released; and transmitting, by the session establisher SIP user agent to the second SIP user agent over the IP network, an end event message to cause the second communication device to deactivate the alert.