[andars]

Looks like they are. Actually a good idea IMO assuming they are just using them as robust 8 bit interconnects and not actually Ethernet.

[hatsunearu]

Considering two of the bits will have large coupling between the two, that sounds like a bad idea...

A 4 bit differential output would be pretty darn good.

Actually, that might be the case: some boards have 4 presumably output ethernet ports.

edit: https://bighexmachine.github.io/hexModuleSpec/ looks like I'm right?

[jda0]

They are, and the interconnects are 4 bit. These were used by first year undergraduates for years before the Big Hex Machine was built, so sturdy Ethernet cables were cheaper and more reliable than many other options.

[AliShug]

Yup, we used 4 wires for data and 4 for power - there's a 12V supply which is spread around and downregulated to 5V on each board. We picked ethernet because it's extremely cheap, hard-wearing, widely available and has enough wires to play with.