Network, private branch exchange, and PBX additional service starting method

摘要

There is disclosed a private branch exchange in which an SIP terminal is capable of receiving great variety of services provided by the private branch exchange without upgrading version of software of the SIP terminal itself. A standard SIP protocol control module 17 and an expanded SIP protocol control module 18 are disposed for SIP corresponding terminals, convert signals from an SIP system protocol corresponding terminal into signals of a protocol inside an IP-PBX 1 to transmit the signals to a PBX basic connection process providing module 12, and convert signals from the PBX basic connection process providing module 12 into signals of an SIP system protocol to transmit the signals to the SIP system protocol corresponding terminal. A PBX additional service providing module 11 and the PBX basic connection process providing module 12 provide additional services in response to an hooking operation from the SIP corresponding terminal or an input of a number for starting the service.