[tdj]

I remember reading about this in the late 90s, open hardware was a fairly new concept then. But you needed to be an electrical engineer to make one yourself, more or less; I wanted to build a pair with a friend so we could play gamed (this was in dialup times). Soon broadband made it obsolete for casual users in urban areas.

There's a modern day equivalent, with up to 10Gbps capability using infrared - http://koruza.net/

[aichi]

Yes, the difference is in speed and distance (150m).

[Kubuxu]

And size.