What is X10?
X10 is a protocol for communication among devices used for home automation. It uses powerline for signaling and control.
X10 was developed by Pico Electronics of Glenrothes, Scotland in 1975. X10 was the first widely available home automation technology and was quite popular due to its low pricing. The X10 technology has received little, in any, updates in the 30+ years of its existence and has largely become a legacy technology.
X10 Ltd went bankrupt in 2011. INSTEON continues to manufacture products which are backwards compatible with the legacy X10 protocol.
X10 sends bursts of 120 kHz(RF) signal, representing digital information, onto the powerline at the zero crossing of the AC sine wave (to minimize interference). Each X10 product can be assigned a house code (A-P) and a unit code (1-16) – thus providing up to 256 unique addresses. Most products contain two small address wheels which are used to set the address.
X10 is largely a one-way technology (signals are not expected to, nor required to be acknowledged). Therefore, each signal is sent twice (A-1:On, A-1:On). Signals take about ½ to ¾ of a second to reach the responder – leading to clearly visible delays between pressing a button and the “light going on”.
X10 is more sensitive to attenuation and line noise than other, more modern powerline technologies. Filters, couplers and repeaters are commonplace requirements. A simulcast signal booster called Boosterlinc is also available from Smarthome/INSTEON.