| 摘要 |
PROBLEM TO BE SOLVED: To prevent a telephone call due to an impersonated call from being performed in a telephone system to be used in a wide range extension service.SOLUTION: A call control server 20 stores the transmission of a call, and transmits a determination object including a call originating extension number and a call originating external line number to an extension server 1 (S37). The extension server 1 receives the determination object (S37), and a caller verification processing section 13 extracts the call originating extension number and the call originating external line number from the determination object, and determines whether or not there exists a record including an extension number which is coincident with the call originating extension number and an external line number which is coincident with the call originating external line number in a conversion table 11 (S39). When there does not exist any pertinent record, the caller verification processing section 13 transmits an error response to the call control server 20 (S41). Since the error response is transmitted, the call control server 20 stops to transmit the held call to a terminal 2000, and transmits the error response to a call control server 80 (S43). |
