Nintendo Light Telephone (オプトエレクトロニクス 光線電話LT, 1971)

The Light Telephone must be one of the most unorthodox of Gunpei Yokoi’s ideas to make it into production (the Chiritori toy vacuum cleaner being another candidate for that title). Like the Kousenjuu light gun series, it demonstrates very creative use of light sensors.

Nintendo Light Telephone (1971)

The Light Telephone's full name is Opto-electronics Light Beam Telephone LT (オプトエレクトロニクス 光線電話LT). The "LT" (obviously) being shorthand for "Light Telephone". The kanji "光線電話" reads as "kōsen denwa".

So, if you are in a vintage toy store in Japan, ask for "oputoerekutoronikusu kōsen denwa eru ti". Chances that they will have one will be slim though, as it is pretty rare these days.

Using visible light to transport sound is immediately intriguing. However, the principal used is not novel. In fact, around ninety years earlier, Alexander Graham Bell and his assistant Charles Sumner Tainter first invented it, and called it the Photophone. With his invention, Bell created the first wireless communication.

Ten years before the release of Nintendo's Light Telephone, an American company called Infrared Industries, Inc already produced a toy based on this technology. It was called the Astro-Phone.

Astro-Phone by Infrared Industries, Inc (1961) [image by Eric Wrobbel]

The full name of this futuristic item from 1961 - labelled as "From the frontiers of science" and "Like Magic" - was Infrared Astro-Phone. It uses a regular flash-light bulb, together with a filter to block all but infrared light. This way, communication happened through intra-red light, invisible for the human eye.

The Astro-Phone had a great design [image by Eric Wrobbel]

But back to the Nintendo Light Telephone.

The sound picked up by the microphone of the Light Telephone is coded into the transmitted light, decoded again by the receiving party’s Light Telephone using a light-dependent resistor (LRD), and played over the headphone. This creates, in effect, a two-way walkie talkie without the use of radio waves.

Looking at the box art, it was pitched more as a novelty item for adults than a children's toy.

Released in 1971 with a price tag of ¥9,800, it was quite expensive and beyond the pocket money league.

The Light Telephone box is big: 55 by 38 centimeters and 13 centimeters high. All items are packed in a two-piece polystyrene foam shell with a cardboard top cover.

The set contains two 'Light Telephones', consisting of a headphone and a hand-piece with a light source, light detector and a microphone. The hand-piece design is a cross between a torch light and an 8mm film camera.

Light Telephone manual front page

Additional accessories included are two plastic "filter-caps" (フイルターキャップ) that limit side-light, and two plastic "attachment hoods" (アタッチメントフード) that further block (sun)light intervening with the reception.

Light Telephone with filter-cap attached

The instruction are fairly simple: both users plug their respective headphones in the hand-piece and aim at each other to make contact. You can speak simultaneously.

The manual explains how the Light Telephone can be used through windows and via mirrors. It can also double as a regular torch (not sure if the rabbit caught in action in the instruction below appreciates this, though).

On the right-side of the Light Telephone's hand-piece a telescope is mounted, which allows the users to take precise aim at each-other, which is necessary for the best reception (well, necessary for any reception for that matter).

A hand-strap is also available, which gives extra grip when handing the heavy (1.3 kilogram!) hand-piece.

Overall, the Light Telephone is very sturdy build, from high quality, durable plastic. A great looking metal embossed name plate is attached to its body.

The "LT" logo and Nintendo branding are added to the filter-cap.

When we take the filter-cap off, we see the plastic lens which is placed in front of the light sensor to focus the incoming light.

A detailed instruction manual is included with the Light Telephone.

Light Telephone manual

On the left-side of the Light Telephone, we see the on/off switch, the battery door and two sockets for the headphone (left) and one for an external microphone (right).

An external microphone is not really needed, as a microphone is integrated in the back of the hand-piece.

The bottom black circle is the exterior of the integrated microphone

A copyright notice (1971) is embossed on the body of the Light Telephone.

The weight of the Light Telephone is for a great part caused by the batteries. This power hungry beast requires no less than 6 batteries per hand-piece: 4 D cells for the light, and 2 AA cells for the electronics.

Now that's a battery compartment! You could park a bus in there.

The total required 12 batteries were included with each set. Nintendo clearly wasn't into this "batteries not included" stuff.

In the bottom of the hand-grip, a metal inner threaded tube is placed.

This can be used to attach it to a standard camera tripod, which allows a much steadier communication between the Light Telephones as well as use over greater distance.

When switched on, the Light Telephone projects a bright beam ahead. This is the light beam that is used to transport the sound from one Light Telephone to the other.

Under the right conditions (not too much sunlight, two sets perfectly aligned) it works surprisingly well for distances of between 10 and 30 meters.

In case of sunlight, the attachment hood can help counter some of the sound quality deterioration which occurs when there is too much environment light.

The head-phone is a basic affair, with a single speaker. The head-band is adjustable to fit various head sizes.

The black foam on the inside of the speaker cup is the only part of the Light Telephone which usually did not stand the test of time very well: after forty years this has often hardened to the point of crumbling.

The Light Telephone contained, for its time, quite elaborate electronics and expensive parts, which explains the high retail price.

The light sensor can be seen at the top of the Light Telephone (the silver component that sits above the light reflector).

It's always cool to see what's inside - have a look under the bonnet, so to speak

The light source is standard light-bulb, which can be replaced easily.

The Light Telephone is one of my favorite Nintendo items. On the one hand it is totally impractical; where walkie-talkies based on radio waves (like Nintendo's own Companion set) can be used day and night, around corners and through walls, the Light Telephone required much more optimal circumstances, in particular that the two people communicating had to be directly facing each other.

However, when you see it working you can only be amazed by the fact that it does work. And it is a lot of fun to use.

That it was released shows that Nintendo was willing to try almost anything at this point in time. And of course, great success seldom comes without any risk taking and trying something new and left-field.

It is not known exactly how well this one fared, but it certainly did not sell in significant numbers, resulting in its current rarity. It was probably a little too odd (and expensive) to garner mass appeal.

A complete Nintendo Light Telephone set

Although the Light Telephone was only sold in Japan, it did attract some attention in the foreign press, as is evident from below article taken from US publication Popular Science (issue December 1971).