CALL CONTROL SYSTEM AND CALL CONTROLLER IN CENTRALIZED EXTENSION PRIVATE SYSTEM

PROBLEM TO BE SOLVED: To improve the continuity of a call connection service and its operating convenience. SOLUTION: A guidance function 603 sends a service guidance denoting it to a caller mobile station that no extension call to a called mobile station is available and denoting a request for selection as to whether the caller mobile station connects to a public mobile network and tries to make a call thereto or interrupts the attempted call, when the caller mobile station (PS) makes the extension call and a called mobile station (PS) is not resident in the service area of the centralized extension private system. A service selection result reception function 604 receives a service selection result selected by the caller mobile station (PS), in response to the service guidance. A call control function 606 derives a mobile station number of the public mobile network from a received extension number according to the service selection result received by the service selection result reception function 604 and makes a fixed network call.