| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication network system where when an incoming call cannot reach a caned fixed phone due to the occurrence of a disaster in a fixed communication network system, a mobile unit can receive the incoming call by using a subscriber number of the called fixed phone. SOLUTION: When a caller fixed phone 1 makes a call to the called fixed phone 5 via a fixed communication system network 14 and a communication fault takes place in a called subscriber exchange 4, an optimum gate switch 8 of a mobile communication system network 15 is selected on the basis of an 'incoming call service allowable indication' stored in a database server 7 and an 'HLR number' specifying a home location register 9 of a mobile unit 13. Furthermore, the home location register 9 stores conversion information to convert a called subscriber number of the called fixed phone 5 into a subscriber number of the mobile unit 13. Then the gate switch 8 specifies the corresponding mobile unit 13 on the basis of the received incoming subscriber number to make communication connection between the caller fixed phone 1 and the mobile unit 13. |
