I have a cat6 wired home network and am facing some issues when terminating the cables on two cables so I can connect to my switch. I have crimped about 5 other cables but two remain elusive.

The cat6 sockets installed by the electrician should have been configured with T568B setup, like the others.

However when I connect a network tester (like this) the results are showing a wiring problem but I'm unsure how to resolve.

When I first connected the tester, the lights lit up as: 8, 7, 4, 3, 6, 5, 2, 1. I then discovered I had put the wires into the plug the wrong way around. So I re-crimped the cable.

However instead of lighting up 1-8 in sequence I am getting the following on two different cables: 1 (2 is not lit), 5, 6, 3, 4, 7, 8.

From what I can tell this means that there is a problem of cable 2 (orange) which may be not crimped properly (it worked before so isn't dead completely) and that the 5/6 and 3/4 are the wrong way around on the socket installed by the electrician. Given that it is the same in two rooms, it seems like an installation problem.

However the sockets in these two rooms are behind furniture so I would like to avoid moving it, opening the socket and re-wiring the socket.

So can I swap 5/6 and 3/4 in the plug to solve this problem? Anything else I should consider? I haven't been able to find much online about how to interpret the network tester results.


At this point you need to fix it on both ends. Ethernet requires that certain pairs of conductors be twisted together. You can get the pinout right but still have certain pins be mispaired (through a twisted pair) with the wrong other pin, resulting in signal integrity problems.

Ethernet requires that pins 1&2, 3&6, 4&5, and 7&8 be paired via twisted conductor pairs (note that 3 is not paired with 4, and 5 is not paired with 6). That pairing is invisible to the kind of cheap "pinout only" cable tester you have, so trying to fix the problem my miswiring one end to counteract the miswiring of the other end is a recipe for mismatched pairs and signal integrity problems.

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  • What you're suggesting will indeed be the best solution. I was just trying to address the issue as quickly as possible. Given that one of this points will provide connectivity to my wireless AP, it makes sense to make sure it is 100% correct. – Ciaran Martin Jun 13 '18 at 8:36

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