Patent ID: 7738642

Claim:
A reverse charging method in a system which is applied to a telephone network in which an IP telephone set communicating through an IP network and a telephone set communicating through an exchange communicate through a media gateway between the IP network and the exchange, and the system has a call agent that performs a call control, and a control apparatus that performs a reverse charging service, wherein the reverse charging method comprising: said call agent detects call origination from the IP telephone set to the telephone set, receives a reverse-charging service number for the reverse charging service, and transmits the reverse-charging service number to said control apparatus; said control apparatus sends a called destination telephone number and/or business company identification information of a called destination as correspond to the received reverse-charging service number, to said call agent; said call agent acquires an IP address of media gateway for communicating with the exchange that accommodates the telephone set of called destination telephone number, and connects the IP telephone set and the telephone set on the basis of the acquired IP address; said control apparatus causes said exchange that accommodates the telephone set to stop charging; said call agent and/or said control apparatus calculate a fee in the IP network and a fee in the telephone network on the basis of talking time; and said call agent and/or said control apparatus generate a fee information by setting charged party information so that a sum of fees in the IP network and the telephone network is charged to the called destination telephone number, and transmit the generated fee information to a PSTN charging management apparatus for the telephone network and also generate a fee information by setting charged party information so that a fee in the IP network is charged to a business company of the business company identification information of the called destination, and transmit the generated fee information to an IP charging management apparatus for the IP network.