IP TELEPHONE SYSTEM, IP TELEPHONE EXCHANGE, IP TELEPHONE SET, AND SPEECH STATE MANAGEMENT METHOD

摘要

PROBLEM TO BE SOLVED: To provide technologies with which a status of an IP telephone set can be speedily recovered, when a call control message could not be transmitted/received normally, between an IP telephone exchange and the IP telephone set.;SOLUTION: When a speech state reported from an IP telephone set indicates "speech path open" and the speech state of the IP telephone set 1 managed by an IP telephone exchange 2 itself indicates "speech path closed", the IP telephone exchange 2 transmits to the IP telephone set 1 a call control message, requesting "speech path to be closed". Furthermore, when the speech state reported from the IP telephone set 1 indicates "speech path closed" and the speech state of the IP telephone set 1 managed by the IP telephone exchange 2 itself indicates "speech path open", the IP telephone exchange 2 transmits to the IP telephone set 1 a call control message requesting "speech path to be open".;COPYRIGHT: (C)2009,JPO&INPIT