An appliance control system includes a central control unit and a plurality of slave units each including a user-programmable microprocessor and respectively plugged into outlet sockets of a power main in a building, appliances being respectively coupled to the slave units. The system permits manual or automatic transmission of command signals and status request signals from the central control unit to individually addressed slave units, and transmission of status signals from the slave units to the central control unit. Certain slave units include lamp dimmers which can be operated either remotely from the central control unit or locally at the slave unit, the microprocessors of these slave units being programmable to remember a predetermined brightness level, so that the lamp can be remotely turned on to that predetermined level. Means are provided for turning the appliance off at the remote appliance site while maintaining the appliance under the control of the central control unit. Means are also provided for reviewing and testing a pre-programmed schedule of command instructions.