[ISL]

The transformer-coupling of Ethernet isn't a trivial fact.

When building precision instrumentation, I was extremely happy to learn about this from one of our old-timers who had been working on systems since the days of the VAX.

You need not worry about DC ground-loops with Ethernet.

When I saw the post-title, I thought, "oh, no, what about the transformer-coupling?". Was very happy to see a simple technique outlined in the article.