smart switch

A wireless light switch is a light switch that commands a light or home appliance to turn itself off or on, instead of interrupting the power line going to the light fixture. There are different ways to communicate between the switch and the fixture:

Using radio transmission: A radio receiver is typically wired or screwed into a fixture or device, wired or otherwise connected to the electrical system of the building or plugged into an outlet. The radio receiver's memory is programmed by any number of means to respond to certain selected "switches" or (more correctly) remote control transmitters.
Using the existing power lines (such as INSTEON or X10): A receiver is plugged into an outlet and a device is then plugged into the receiver. The plug-in receiver is then programmed to the switches. Some devices are hard wired into ceiling light fittings, making for a hidden system.

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