An UPnP control point is connected to an IEEE802 network, and 1394 equipment is connected to an IEEE1394 network. The IEEE802 network and the IEEE1394 network are connected to each other through an UPnP device functioning as a bridge. The UPnP device receives from a general bus input plug a packet transmitted from the UPnP control point, converts it to a format of the IEEE1394 network, and transmits it from an output plug through the IEEE1394 network to the 1394 equipment. The UPnP device stores the association relationship of the plugs.