I am wiring up my house to Cat5 sockets and have a couple of different styles of sockets and was wondering do I just follow the colours on the back of the sockets, or do the same configuration of wiring on all sockets?

**enter image description here**

  • 3
    That would depend on what kind of cabling you want. Usually you'd go for straight through "between sockets". See also EIA/TIA 568A & 568B Standard
    – Seth
    Aug 16 '17 at 11:51
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    also, as someone who has had a lot of trouble learning to cable buy a cable tester and use that to work out if things are correct.
    – Journeyman Geek
    Aug 16 '17 at 12:24
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    Just about everyone uses 548B as indicated on these modules. The difference in layout is down to the routing of the wires between the punchdown and pins, the actual order of the colours to conductors is the same.
    – Kaithar
    Aug 16 '17 at 13:53
  • 1
    Generally speaking, it makes the job go easier if you use the same style of jack everywhere on the site. Not always possible of course.
    – Criggie
    Aug 16 '17 at 22:32
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    @Seth that's a fair point, who knows what embedded kit does or doesn't support heh. Admittedly, only one end needs MDI-X if I understand the tech correctly, but who knows.
    – Kaithar
    Aug 17 '17 at 13:49

TL;DR: Yes, you can just follow the colours on the back of the sockets.

Expanded answer: Ethernet uses four pairs of wires with differential signaling. In the cable, the two wires in a pair are twisted around each other, following the colors: green and green-white, blue and blue-white, etc. The pairs have a slightly different rate of number of twists per length. That reduces crosstalk between pairs, so it's important to get the pairs right.

There are actually two ways to distribute the pairs, 568A and 568B. For a cross-over patch cable, you'd crimp one end according to 568A, and the other according to 568B. But today's hardware can automatically adjust to cross-over or straight-through connections, so getting this right is only important if you are using really old hardware.

In theory, a cross-over connection could also be made between sockets (not following the colors on one end), but you can always do the crossing over in a patch cable, if really necessary. So just following the colours in the sockets is fine.

Additional info, because this regularly trips up people: There are two kinds of Cat5 wires, a solid-core "installation" variant and a stranded "patch" variant. The solid-core "installation" variant is one you should run inside the walls and connect with the sockets in your picture. If you try to connect the stranded "patch" variant to those sockets, the connection will be bad.

Because the this variant is a bit stiffer, be careful when bending it, and don't try to put it around sharp corners.

Vice versa, most RJ45 plugs are for the stranded "patch" variant. If you try to crimp the solid-core "installation" variant, the connection is not firm and will come loose over time (or immediately, in some cases). There are special RJ45 plugs together with special crimp tools that work for the solid-core variant. So in a pinch, if you really must, you can put an RJ45 plug of those. But usually it's better to just put in a socket in this place, and use a patch cable to get a plug.

In any case, make sure to buy and use the correct type of cable with the sockets and RJ45 plugs you have.

  • 2
    +1. Learnt something new today. VERY useful to know about the different types (stranded vs. solid core) for when doing installations vs. patch cables.
    – Kinnectus
    Aug 16 '17 at 12:47
  • For extra lulz, if you try to terminate solid core with an rj45 you can end up just outright cutting through the conductor and have it look ok but not actually in contact at all.
    – Kaithar
    Aug 16 '17 at 13:50
  • @Kaithar This is only the case if you don't use rj45 connectors intended for solid cable. These mate differently to the wires so they don't simply chop them off.
    – Luke G.
    Aug 16 '17 at 15:17
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    @LukeG. I'd assume they're built using a better blade profile, similar to how the blades are shaped on a punch down block, but I can't honestly say I remember ever knowingly encountering that kind of plug in practice and I wouldn't entirely trust them for that application either, just on principle of how solid core behaves.
    – Kaithar
    Aug 16 '17 at 15:43
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    Be sure to be consistent to make sure you have a reliable network, i.e., don't use 568a in one spot, then use 568b somewhere else, it will only make it difficult to keep track, and therefore difficult to troubleshoot.
    – Davidw
    Aug 16 '17 at 19:34

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