The author seems unfamiliar with Radio Shack's Plug 'n Power, which was first introduced in 1979. >The modules were designed to respond to commands sent over t

The author seems unfamiliar with Radio Shack's Plug 'n Power, which was first introduced in 1979. >The modules were designed to respond to commands sent over the electrical wires inside the house. They could turn on or off, or in the case of a lamp, change brightness. The advantage of using a power-line communication system was that it didn’t require any additional (and costly) signal wiring. http://www.trs-80.org/plug-n-power/ http://www.trs-80.org/plug-n-power/