In 1956, Zenith developed one of the earliest wireless TV remote control devices. It featured a small hammer inside the remote that could be used to strike one of four aluminum bars, producing an ultrasonic sound that was too high-pitched for humans to hear. This sound was then used to transmit signals to the TV, allowing the user to control it remotely.
While customers appreciated being able to control their TV from a distance, they often complained about the unattractive cable that ran across the floor and posed a tripping hazard.
