METHOD OF ESTABLISHING FREE CHARGE COMMUNICATION CONNECTION, SERVICE UNIT, EXCHANGE AND COMMUNICATION NETWORK

摘要

PROBLEM TO BE SOLVED: To provide a method for free charge communication connection, where free charge conventional call numbers that require no central management are used. SOLUTION: In order to connect a caller terminal TE21 connecting to a 1st communication network KN1 and a called terminal in free charge, a service unit SERV of a 2nd communication network KN2 sends a connection a request of a free charge conventional call number IFN which is used for a called party number to the 1st communication network KN1. After recognizing the connection request as being that with the free charge conventional call number, the 1st communication network KN1 sends an inquiry of the 2nd communication network thereto. The service unit decides a free charge local call number of the 1st communication network, based on the free charge conventional call number and returns the free charge local call number to the 1st communication network. The 1st communication network makes requested connection in accordance with the decided free charge local call number.