Internet telephony gateway and method for operating internet telephony gateway

摘要

An Internet telephony gateway that connects a PSTN with an IP network and a method for operating the Internet telephony gateway are disclosed. When abnormal services due to matching between networks are interrupted, the Internet telephony gateway performs a flow for terminating a call with a corresponding subscriber terminal unit using an internal failure alarm system. The flow includes a message of a failure alarm, a tone, and an announcement.