X10 is a protocol used in home electronics and automation where digital inforation is coded and transfered over the 60hz sine wave to receivers pluged into wall sockets. Ones are placed by adding a 1khz 'block' near the zero of the sine wave. The lack of such a block is interpreted as a zero. This is then decoded by the receivers and turned into various outputs such as removing power from that outlet to, say, turn off a light. x10.com markets video devices and other products compatable with this protocol.