In Power Line Communications, digital signals connect the electronics in the home or office through the existing power lines within a building. A PLC can be used to provide: online reading of utility meters for easy, up-to-date billing, surveillance system data in security systems, remote maintenance and in-house control of internet, enabled household appliances like heating systems, internet and refrigerators in Smart Home applications. Optocouplers can be used in the switching power supply of the PLC device as well as in the coupling circuit between the device and the power line.