top number is transmitter bottom number is remote terminator


is this because I could be mixing T568A and T568B wiring? how do I know if my patch cord is A or B? Do I just look at the plug and match it up with the diagram on the back of the panel somehow?

plug wired patch panel

EDIT I read that 36145278 indicates a cross over cable, but I'm not trying to make a cross over. Where did I go wrong? I'm guessing the cable plug is T568A but I wired it to the panel using T568B. So I need to redo it as T568A. But in the future how do I know if I cable is A or B?


  • 1
    why are you wiring one end to a patch block with the other end a rj45 male? – TheCleaner Apr 17 '13 at 18:45
  • the devices which connect to the patch panel might move around. so they connect with patch cords. but the switch on the other end of the patch panel is in. permanent location. so I can spare myself the effort of another patch panel by just connecting the cables to the switch. is anything terribly wrong with this idea? – Max Hodges Apr 17 '13 at 19:05
  • Not necessarily, just not what you typically see. – TheCleaner Apr 18 '13 at 12:58

You can see that the rj45 plug has the blue wires in the center whereas on the patch panel they are on the side.

I know you explained why you have a patch panel on one end and a plug on the other, but it's generally not a good idea to mix both types. On both ends of the cable should be either a female or a male end.

The reason for this is that patch panels/blocks work best with solid core cables, but plugs are most effective with stranded cables. The ideal situation would be less than 90 meter of cable running from a patch panel near the router to a wall socket, and then connect the device to the wall socket with a patch cable with two plugs on both ends, shorter than 10 meter.

The problem with putting an rj45 plug on a solid core cable is that the little 'knifes' inside the plug don't cut into the wire as they would with stranded cable. They just sit on top of it, often giving you bad or even no connection at all.


OK let me know if I'm wrong here but I think I figured it out.

Basically if one side of the plug starts with WHITE/ORANGE its T568B. If one side starts with WHITE/GREEN then its T568A.

If one end is T568A and the other is T568B then its a crossover.

  • 1
    Crossover is obsolete and you should never make one for Gigabit or almost never for 100Mbps. Also, you need to untwist as little wire as possible. You've removed about two more twists than you should -- that allows the signals to interfere with each other where they're untwisted. – David Schwartz Apr 17 '13 at 17:46
  • thanks for the tips! I assume you think my answer here is on track? – Max Hodges Apr 17 '13 at 19:08

Ok, Here's the solution and it's pretty easy actually, if you know....

So I'm not a Network expert but I knew the solution was easy. I was punching down on my patch panel and terminating on the other end with an rj45. I was doing 568B on both ends and it wasn't working. I was looking at the diagram on the patch panel and it wasn't either B or A, it just had all the colors paired up together. So after almost a week of fudging with it I finally figured out that the patch panel itself internally crosses the pairs so that it ends up being a B pattern. That makes it easier for when you're punching down hundreds of Ethernet cable. You just go along with the colors instead of trying to remember the correct pattern. Hope this helps cause it was the simple answer I was looking for... Terminate or punch down with 568B on one end and then just punch down according to the diagram on the patch panel. DONE!


Yes, you are terminating T568A and then, testing T568B. Just flip your green and orange pairs.

In the T568A pinout, the pairs 1&2 (white & green), and 3&6 (white & orange) are opposite of what the pinouts in T568B are. In T568B, the pairs are 1&2 (white & orange), and 3&6 (white & green). Both T568A and T568B have the same pinouts for pairs 4&5 (blue & white), and 7&8 (white & brown). In ALL pinouts the white wire that is paired with its colored partner is called the "tip", and the colored wire in every pair is known as the "ring".

Whether you use a T568A or T568B patch cable will not matter as "electrons are colorblind"...as long as the pinouts on both ends are the same, either will work. Make sure to maintain your network standard (Cat.5e or Cat.6). If you use any Cat.5e items on a Cat.6 network, you will lower all your metrics to that Cat.5e standard. As long as your patch cable ends are pinned-out the same (straight through) to either the T568A or the T568B pinout, you will be okay.

A "crossover" patch cable is pinned-out to T568A at one end, and to T568B at the other end. They are (or were) typically used when cascading two or more network hubs or switches. The advent of "smart switches" has pretty much negated their use.


I haven't done this in years, but I believe T568B to T568A is a crossover cable for 10/100BaseT connections and you will need to make a gigabyte crossover cable to go faster.

I found a reference link for you: http://en.wikipedia.org/wiki/Ethernet_crossover_cable#Crossover_cable_pinouts

  • 1
    There is no such thing as a gigabit crossover cable. Gigabit interfaces automatically cross over when needed. – Grant May 29 '14 at 2:40

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