The present invention relates to a communication apparatus including a plurality of interfaces and the interfaces are selected to enable detour call reception. A power-supplied interface is allowed to receive a call correspondingly to the selection of the interface. A plurality of networks (cellular network, WLAN network) and a communicating apparatus (communication terminal apparatus) wirelessly connected to a network apparatus (cellular switchboard, SIP server) disposed in each network are included. The communicating apparatus includes a plurality of interface units (cellular interface unit, WLAN interface unit) corresponding to the networks. Connection of a power source is switched for the interface units, and some or all of the networks are notified of detour destination information for detouring the call from the network to the interface unit of the call destination. The network apparatus receives the detour destination information to detour the call to the interface unit of the detour destination.