The Infraphone, invented by Douglas Reddan circa 1960, used infrared light to allow people to communicate wirelessly at distances of several hundred yards. You had to aim your infraphone at another infraphone, which you did by looking through a sight on top of the unit. Then you could talk into the device, just like using a phone.

It's an interesting idea, but I can't really think of a situation when this would provide an advantage over using a radio walkie talkie. Maybe because the signal can't be intercepted as easily? But then there's the awkwardness of having to aim the device. Articles about it frequently suggested it could be used as a wireless intercom.

Eugene Guard - Nov 14, 1960

Palm Beach Post - June 4, 1961

Popular electronics - Feb 1961 (via RF Cafe)

     Posted By: Alex - Sat Aug 12, 2017
     Category: Inventions | Telephones | 1960s

It's my understanding its biggest advantage is it didn't use radio frequencies. If you had people widely-separated in a field (search, survey, etc.), they could carry on several conversations simultaneously without interfering with each other. Because their circuitry is a subset of what radio communications need, you could buy maybe a dozen of these for the price of one multi-band walkie-talkie.

You didn't need to assign different frequencies to different crews, know the frequency of the person you want to talk to, or distract everyone in the area with calls to a common channel reserved for "I want to talk to Bob. Meet me on frequency twenty-three" messages.

Also, if you got lost (and the staff was prepared for the eventuality of people getting lost), you could use this as a beacon for a searcher with an old-fashioned Sniperscope.

The obvious problems (no way of alerting someone you wanted to talk to, and it had to be line of sight) doomed it, and rapidly evolving integrated circuitry making radio communications much less expensive would have made it obsolete within a few years.

But for one brief moment in time, it best fulfilled one little (virtually minuscule) niche.
Posted by Phideaux on 08/12/17 at 10:21 AM
Devices like these are the ancestor not of wireless communication, but of remote controls like those we use on TV sets.
Posted by Brian on 08/12/17 at 02:24 PM
There are devices for high speed Internet that use optical transceivers in place of fiber optic lines, where wireless connections are desired.
Posted by RobK on 08/14/17 at 10:41 AM
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