Patent ID: 7970113

Claim:
A private branch exchange system comprising: an analog circuit interface section which is connected to an analog circuit of a public network, receives an incoming call signal, a caller ID showing a caller's number and a speech signal from the analog circuit, outputs incoming call signal presence information that shows whether to receive the incoming call signal that has information indicated at a predetermined position on a highway and outputs the caller ID to a speech signal path which is a route through which the speech signal passes; an analog extension interface section which is connected to an analog extension of a private branch, sends out the incoming call signal, the caller ID and the speech signal to the analog extension, detects the incoming call signal presence information on the highway, detects the caller ID on the speech signal path, generates an incoming call signal based on the detected incoming signal presence information and sends out the generated incoming call signal and the detected caller ID to the analog extension; and a system control section which is connected between the analog circuit interface section and the analog extension interface section to connect the speech signal path.