A control system for controlling a power line network having a power line, at least one electric appliance and at least one controller includes a central control unit, configured to realize programmable controls over the appliance by the controller with signals transmitted through the power line. An on-site control unit includes at least one modulator and at least one demodulator coupled with the central control unit. Each modulator is configured, upon receiving a first control signal from the controller, to generate and transmit a second control signal to the central control unit that is configured, upon receiving the second control signal, to generate and transmit a third control signal to the demodulator. Each demodulator is configured, upon receiving the third control signal, to generate and transmit a fourth control signal to the appliance.