TOLL FREE SERVICE SYSTEM OF IP PBX

摘要

A free charge telephone service system between IP PBXes(Internet Protocol Private Branch Exchange) is provided to enable a service subscriber to receive a toll free service for a corresponding cooperation company, which the service subscriber frequently calls on business, like a part of the company of the service subscriber, thereby improving a degree of recognition for a communication service provider by a supplementary service and improving sales by increasing the call. A method for providing a free charge telephone service comprises the following steps of: determining whether a request telephone number is an extension number or a normal telephone number when a call is requested; determining whether a caller is a subscriber subscribed to an extension service and providing the extension service; storing a call history even when the call is the toll free service; and regarding charge information as free.