[tomfanning]

Wheel successfully reinvented :)

Nothing stopping you setting up a whole AX.25 network between multiple machines using Dire Wolf [1] and the built-in AX.25 [2] (a derivation of X.25) support still in the Linux kernel. You get a proper network interface that shows up alongside eth0. Nice short instructions at [3]. Just don't hook it up to radios unless you're appropriately licensed. Speakers and mics only.

[1] https://github.com/wb2osz/direwolf

[2] https://en.wikipedia.org/wiki/AX.25

[3] https://g7vrd.co.uk/ax25-direwolf-linux

[em3rgent0rdr]

Also the "BadBIOS" hypothetical malware from 2013 that spreads via computer speakers & mics [1].

[1] https://en.wikipedia.org/wiki/BadBIOS