Still, in the highly competitive environment of the early TV business, some manufacturers offered limited remote-control functions, by way of a thick cable to the TV set. Most of these just turned the set on and on, and changed the volume, contrast, brightness, etc. Some included a complete tuner in the large tabletop box, so that the channel could be changed (and fine-tuned) from your easy chair.
By 1950, TV set manufacture had become more sophisticated and "labor-saving" devices of all sorts were the rage. For the 1951 model year, Zenith introduced the Lazy Bones remote control -- a styled, handheld pushbutton connected by a wire to the television. There, a motor moved the channel selector forward one notch for each press of the button. Stable sync and tuning circuits meant that viewers could more reliably change channels without adjustment. However, you still had to get up to adjust volume or turn the set on and off. A few other manufacturers offered similar wired remotes, but they were all expensive and clumsy, and did not sell well.
A further advance in technology -- to wireless remote control -- was made by Zenith in 1955, with their Flash-Matic Tuning product. This was a cordless flashlight-like device (in fact a flashlight could probably have been used) that you aimed at the set. Photocells were mounted at the four corners of the (now rectangular) picture tube bezel for "Channel Up," "Channel Down," "Off," and "On" functions. Flashing the light at the appropriate target photocell activated the function. By this time, Zenith was nearly alone in offering remote control for television sets.
Ambient light was probably the downfall of the Flash-Matic system, because in 1957 Zenith introduced the first "clicker" -- the Space Command remote control. This revolutionary device used ultrasonic tones generated by tuned rods that were struck by the keys on the cigarette-box sized control. You now could change the channels up and down, turn the set on and off, and turn the sound on and off (still no volume control). To the user, pressing the buttons made only a clicking or muffled twanging sound, hence the name "clicker" that has stuck with us. A four-channel ultrasonic receiver detected the tones and operated the tuning motor and control relays in the set. An advantage of this system was that the remote control required no batteries -- its operation was mechanical. A drawback of the ultrasonic control method was that other items could produce sounds at the right frequencies, triggering unexpected operation of the set. Dog tags or sets of keys jingling were common triggers. Still, this method was the best available for many years, and led to a slight resurgence in the availability of TV remote controls.
Ultrasonic remote controls became more and more sophisticated, and additional functions were added. Early limitations were the number of distinct control tones that could be generated mechanically and detected reliably at the set. RCA replaced the tone rods (or bellows-operated whistles) with an electronically generated signal and a special tiny speaker, allowing more tones, and so more functions. (Of course this meant that the remote control now needed a battery.) This was important for color television, which took quite a few years to develop stable color circuits -- tint and color-level controls were almost as commonly adjusted as the the volume control. More advanced filtering eliminated some, but never all, of the "falsing" -- the accidental triggering of set operation by incidental ultrasonic noises. Channel-changing at the set was still performed with a motor turning the tuner knob.
By the early 1970s, semiconductors had advanced to the point where Light Emitting Diodes (LEDs) were becoming common and cheap. A characteristic of silicon LEDs is that they "want" to emit light in the near-infrared (IR) region. Likewise, silicon-based photocells are most responsive to the same frequency of light, and had become fast enough to respond to ultrasonic speed light impulses. Since IR LEDs and phototransistors were smaller, lower power, and cheaper to make than the ultrasonic speakers and microphones, and almost completely immune from falsing, it was only a short time before they were predominant. Additionally, TV tuners began to be electronically rather than mechanically tuned, so the noisy and slow channel-changing motor could be dispensed with. The lowered production costs meant that, for the first time, remote controls had become an affordable option for most consumers.
The IR remote control that we know today was fully developed by the late '70s, as microprocessors began to be used as tuner controllers, and, by rapid extension, as the "brains" of the entire TV set. Control signals are sent from remote to set on a series of on-off pulses of IR light, typically at a 38 kHz rate. Digital pulse trains contain redundant information to eliminate falsing, and each set manufacturer has a unique code or codes to prevent accidental triggering by other remote controls.
The first "Universal" remote control was developed by North American Philips Consumer Electronics in 1983. By containing the codes for a very large number of different TV sets, it could be programmed to operate any of them. Other Universal remotes "learned" a set's codes by reading the IR signals from their remotes (a "cloning" operation), or by entering an identifying number through the keypad or a hidden switch.
Last Updated: January 30, 2010