[manbart]

Gigabit Ethernet require 4 twisted pairs i.e. 8 individual cables. 100Mb Ethernet requires 2 pairs i.e. 4 individual cables. At least in standard configuration

[stefan_]

There is a standard for Gbit over a single pair: Single Pair Ethernet (SPE). But it's more of a rare automotive thing, so I'm also confused how the grandparent made this work.

[y1n0]

Used on rockets too. Harnessing is a major contributor to non-payload mass.