The HomeLink Wireless Control System is a radio frequency (RF) transmitter integrated into some automobiles that can be programmed to activate devices such as garage door openers, RF-controlled lighting, gates and locks, including those with rolling codes. The system features three buttons, most often found on the driver-side visor or on the overhead console, which can be programmed via a training sequence to replace existing remote controls. It is compatible with most RF-controlled garage door openers, as well as home automation systems such as those based on the X10 protocol. It won the PACE Award in 1997, for supplying automotive technology to improve interaction between the consumer, the car, and home. By 2003, it had been installed on over 20,000,000 automobiles. Originally made by Johnson Controls, the HomeLink product line was sold to Gentex in 2013.