X10 is a communication standard for home automation, or more simply put, it is a language with which home appliances, such as lights, security systems and computers, can send and receive information to each other. Practical uses for X10 home automation include controlling lights and turning on security systems wirelessly.
Scottish electronics technicians developed the X10 protocol when creating a device to switch records in a record player. They realized the potential of the standard when they applied the idea of remote communication to home lighting systems and other electronics. The simple system saw wide adoption in the decade after its creation, cresting when General Electric developed home appliances with the protocol in 1984.
X10 home automation originally relied on power lines to communicate information by translating digital data into 120 khz, or radio frequency (RF), signals. With the advent of wireless RF communication, X10 became untethered from house power lines. Wireless communication freed X10 of the limitations of using house power lines, which weren't conducive to sending clear X10 signals. The communication standard sends all information twice to ensure the information isn't lost over noisy power lines.
As of 2015, X10 home automation sees little use modern homes, as the protocol has had few updates since its inception in the mid-1970s.