 A remote control is primarily a convenience feature for the user, and can allow operation of devices that are out of convenient reach for direct operation of controls.In some cases, remote controls allow a person to operate a device that they otherwise would not be able to reach, as when a garage door opener is triggered from outside or when a Digital Light Processing projector that is mounted on a high ceiling is controlled by a person from the floor level.Early television remote controls (1956–1977) used ultrasonic tones.