Erik Voskuil writes, "Before Nintendo became a global household name, it already had a rich history producing fun and, in some cases, downright wacky toys and games. The Light Telephone must be one of their most unorthodox ideas to make it into production. The sound picked up by the microphone is coded into the transmitted light, decoded again by the receiving party’s Light Telephone using a solar cell, and played over the headphone. This creates, in effect, a two-way walkie talkie without the use of radio waves."
The Nintendo Light Telephone was released in 1971 to capitalize on the walkie talkie and CB radio craze. each 1.3 kg handset included a telescope to allow precise aiming of the light beam at the solar cell receiver on the other handset, although a tripod would be needed at long range.
Because it's sensitive to bright sunlight, this is one toy that would work best in the dark. That said, it would have been impossible for a pair of kids to have a clandestine conversation at night with a pair of giant flashlights giving away their every move.
The Light Telephone was priced at 9,800 Yen (approximately $27 at the 1971 exchange rate), a hefty price tag that probably limited its popularity. That's a pity, because this has to be one of the craziest, coolest and most collectible Nintendo products ever.
Nintendo Light Telephone [beforemario.com]