As known, the Ethernet standard from the GBe range also prescribes the auto-detection of the cable type (in the sense of it is crossover or ordinary cable), thus there is no really need to use crossover cables any more.

However, we have here a switch panel, and it is a fully passive thing.

The physical connection between a single device and the switch looks so:

EndDevice -- Cable1 -- Patchpanel -- Cable2 -- Switch

(Really, it is EndDevice -- Cable1 -- Wall Socket -- Cable2 -- PatchPanel -- Cable3 -- Switch, but the essence of the question is the same.)

As the standard says, there wouldn't be a source of trouble if the devices would connect into the switch directly: the chips on both sides should detect that they have a crossover or patch cable between them, and they should act accordingly.

But, I think, it is an active thing. There should be an electronic, which detects the carrier signals, and alters the ordering of the read/write PINs of the logical interfaces.

The patch panels are passive. Typically, they have only wires and connectors, but no chips. Thus, in their case, there is nothing, what could do the required adaptation.

Do the network still work in any configuration, i.e. can Cable1 and Cable2 be any combination of patch/crossover cables?

  • "alters the ordering of the read/write PINs of the logical interfaces" 1000BASE-TX actually uses all the pairs for both send and receive. – Ron Maupin Feb 7 '18 at 23:43

Yes it will still works due to auto-detection.

Having two (or actually any even number) of crossover cable is equivalent to a straight cable.

Similarly having any odd number of crossover cables result in a crossover link.

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