TwinAx Came Back Because Physics Kept the Receipt
One of the stranger pleasures of building out a modern local network is watching an old idea become the right answer again.
In my lifetime, TwinAx went from being standard on big iron, to feeling obsolete, to quietly becoming relevant again in high-speed local networks.
Different connectors. Different switches. Very different speeds. But the underlying reason is familiar: when you need to move a lot of signal a short distance with low heat, low power, and predictable behavior, direct-attach copper starts making a lot of sense.
RJ45 won the everyday world because it was cheap, flexible, familiar, and good enough. And for a long time, that was the right answer.
But at 10G and above, especially inside a rack, between workstations, servers, storage, and aggregation switches, physics starts voting again.
Signal integrity matters. Heat matters. Power draw matters. Distance matters. Latency matters. Complexity matters.
And none of those things care very much about what is fashionable.
That is one of the humbling things about infrastructure. You can change the language, the branding, the management layer, and the packaging. But you cannot overrule basic physics. At some point, the electrons still get a say.
It also makes me appreciate older engineers (like myself) and older ideas differently. Sometimes what looks outdated was not wrong. It was simply waiting for the problem to come back around.
Good engineering ideas do not always disappear. Sometimes they wait patiently until the constraints make them obvious again.
It is not nostalgia.
TwinAx came back because physics kept the receipt. #Networking #Infrastructure #Homelab #LocalFirst #SystemsThinking
Originally published on LinkedIn on June 11, 2026 by Charles David Butler II.
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