(It was developed by the Zenith Radio Corporation in 1950 and it was connected to the television set by a wire. A wireless remote control, the "Flashmatic", was developed in 1955; it worked by shining a beam of light onto a photoelectric cell, but the cell did not distinguish between light from the remote and light from other sources. Then in 1956, Robert Adler developed "Zenith Space Command", a wireless remote. It was mechanical and used ultrasound to change the channel and volume. Unfortunately the receiver could be triggered accidentally by naturally occurring noises, like the whislting of budgerigars, and some people could even hear the piercing ultrasonic signals.)