Power switch module (4ch) has relay on-off and relay status indication functions. The master device (M) uses power line carrier communication to interact with the gateway, and uses RS485 to communicate with access slave devices. Each master device can manage 3 slave devices. The slave device (S) uses RS485 to communicate with the master device. Both master and slave devices can control the load loop, which is mainly used in the lighting system of smart business offices and smart homes to complete the intelligent lighting.