A system is provided which is capable of connecting a call without degrading the security level in a mobile terminal network, even when a call addressed to a user equipment (UE) arrives via the Internet or a home network. A femto base station receives a packet addressed to a UE via the Internet or a home network, and starts a paging procedure. The UE establishes an RRC connection to the femto base station. The UE transmits, to the femto base station, a paging response addressed to the SGSN. The femto base station performs NAS verification. If the femto base station detects the paging response to a paging request that the femto base station itself has issued, the femto base station changes the service type of the service request received from the UE from the paging response to signaling.