Figure below is a networking scheme for hotels. As there is no ammeters in guest rooms, it is convenient and efficient for us to inject signal in networking. Because each hotel floor is relatively large in area, a PLC bridge and a adaptor are used on each floor.  The PLC bridge (FPC-10M) is connected to switch through category 5 UTP and the signal injection into three phase power sources is done through adaptor (FPA-10M) in the power shaft.