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One of my ethernet cables starting malfunctioning, so I decided to replace it. The problem is, it turns out that the old cable is neither straight nor cross. It has all pairs mirrored (1-8 2-7 3-6 4-5 5-4 6-3 7-2 8-1). I narrowed the problem down to ethernet extender (like the one here: )
which, if disassembled, has a circuit board inside that also mirrors all pairs. So the cable is mirrored basically to fix mirroring inside extender.
The question is, what is all that? Where does it come from? Is it described by some standard? The extender is factory-made, and the cables are definitely not made by trial and error.