> Differential measurements ... explains why Ethernet cables come wired as 4 twisted pairs. The pairs in Ethernet also allow use of transformers, so there's no

> Differential measurements ... explains why Ethernet cables come wired as 4 twisted pairs. The pairs in Ethernet also allow use of transformers, so there's no need for a common ground between the devices the cable connects. Balanced audio connections might be a better example of a differential signal, in that instance to reject noise.