A modular power device is used for mounting on a main plate. The box body has one side defining an opening and has two inner walls each provided with a guide track which is provided with a lug that defines an insertion groove. The system also includes an optical connection positioned outside the casing and optically coupled to the viewport. Moreover the network according to the invention allows the data collected by mobile users to be shared with other mobile users, thus forming a peer-to-peer network.