[tiborsaas]

> bitrate of 20 bits/s

I can imagine this being used as a control protocol for home/building automation, 20 bits is quite a lot if you consider each bit a device being turned on or off only.

I still don't know why would anyone do this instead of wifi, but definitely way cooler. Also, anyone visits you the first time, there's a guaranteed 20 minute talk about the setup :)

[jcims]

Would make for a pretty stealthy bootstrapping protocol to share things like wifi keys between devices or to do keystroke logging.

[em3rgent0rdr]

speaking of stealth, there was this (hypothetical?) malware from 2013 which spread via computer speakers: https://en.wikipedia.org/wiki/BadBIOS