Power Line Communication
Power line communication (PLC), also called power line carrier, mains communication, power line telecom (PLT), or power line networking (PLN), are terms describing several different systems for using electric power lines to carry radio signals for communication purposes.
Power line communications technology can also be used to interconnect (network) home computers, peripherals or other networked consumer peripherals, although at present there is no universal standard for this type of application. Standards for power line home networking have been developed by a number of different companies within the framework of the HomePlug Powerline Alliance and the Universal Powerline Association.
Basically the sockets convert an Ethernet signal and transmit it over the household wiring, essentially turning your household wiring into a Ethernet hub.
Several competing standards are evolving including the HomePlug Powerline Alliance, Universal Powerline Association, ETSI, and the IEEE. It is unclear which standard will come out ahead.
There are two basic HomePlug standards, HomePlug 1.0 and the newer HomePlug AV. HomePlug 1.0 is a 14Mbit/s half-duplex standard with a proprietary but widely deployed "Turbo" 85Mbit/s half-duplex extension. The newer non-interoperable AV standard runs at 200Mbit/s half-duplex. You can run both 1.0 and AV systems on the same network but they do not communicate.
There is a non HomePlug standard based on the OPERA standard which can also deliver a 200Mbit/s half-duplex, however it is not compatible with the HomePlug 1.0 or AV standard, though like the HomePlug AV standard it can co-exist with the HomePlug 1.0 standard.
Kit Available on The UK Market
Within the UK market Devolo, Solwise, Linksys and others offer single and pairs of units in the HomePlug 1.0, 1.0 Turbo and AV standards. Netgear and D-Link support the OPERA 200Mbit/s standard. The older Netgear kit is HomePlug 1.0 and Turbo standards based. Expect to pay around £120 for a pair of 200Mbit/s sockets.