Crimp a straight cable and a cross cable, How and what difference?

Made up of four pairs of colored wires, network cables are not made the same. Their differences lie in the norms that govern them and in the order of threads that compose them. In this article, we will see how to Crimp a straight and crossover cable, trying to understand the difference between the two.

Crimp a straight and crossed cable: T568A and T568B standards

Before we get to the issue of crimping, let's take a quick look at what it is T568A et T568B. These are standards used to specify the arrangement of colored pairs, and define the nature of the cable according to whether it is straight or crossed. Both show the wiring diagram for network cables with RJ45 type connector.

Standard T568A vs Standard T568B

Regarding these two standards, the main difference is the position occupied by the pairs of wires. Orange et white-orange, and the pairs green et white-green, although nowadays the T568B standard has largely replaced the T568A standard.

You can decide to arrange the wires according to the standard that suits you, but remember that one (T568A) is more used in personal networks, while the other (T568B) is mainly used in company networks (level professional, often with shielded cables).

Crimp a straight and crossed cable: Connector and RJ45 port

Le RJ45 (RJ for Registered Jack), designates a physical interface that serves as a termination for twisted pair cables. It is also called 8P8C (8 points, 8 contacts), reference made to its 8-pin termination (4 pairs, two to two).

RJ45 connector and port

It is commonly used on Ethernet cables, and allows for several types of cables.

Crimping a straight and crossed cable: what's the difference?

The main difference between the two types of cables is that the first (straight) is used to connect equipment of a different nature such as a switch and a router, a switch and a computer, etc. while the second (crossed) is used to connect equipment of the same nature such as a switch and a switch, a computer and a computer, etc.

Equipment connected by straight cable and crossed cable

The crossover cable reverses the transmit and receive signals.

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The color code for crimping a cable

To crimp a cable, the color code generally used is as follows:

1.Orange-white | 2.Orange | 3.Green-white | 4.Blue | 5.Blue-white | 6.Green | 7.Brown-white | 8.Brown.

Order of cables according to T568B standard

As you can see, the color code is the one relative to the T568B standard. Remember that this is the most widely used standard.

To get a straight cable, use the same order of colors to crimp the two ends of your cable. That is to say it is absolutely necessary that the order of the wires is identical on the two RJ45 connectors, so do not change anything.

As for the crossover cable, the difference is in the swapping of some wires of the second connector. So to get a crossed cable, take the first connector and store the wires in the previous order, that is to say:

Wire order table for both ends of a crossover cable

The image below illustrates the difference between the two connectors of the crossover cable.

crossover cable

In short: to have a crossed cable, crimp the first connector (you can arrange the wires in any order, no need to follow the standards if you want to make a small cable for private use) and, crimping the second connector, swap 1 and 2 of the first connector with respectively, 3 and 6 of the second connector.

A simple trick to remember this by heart is to use the number 3. One you multiply 1 * 3, you get 3 as the answer (1 as the first wire of the first connector, and the answer 3 as the wire of the second connector to swap with 1).

Do now * 2 3, you get 6 as the answer (2 as the second wire of the first connector, and the answer 6 as the wire of the second connector to swap with 2).

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Crimping steps

To crimp a straight and crossed cable, here are the steps to follow:

  • Strip the cable with a wire stripper and cut off the ends. Be careful not to damage the wires.
  • Separate the threads and do it by untwisting them. Please make the wires straight and elongated so that they are easily inserted into the connector.
  • Arrange the wires according to their colors (preferably by following the T568B standard: white-orange, orange, white-green, blue, white-blue, green, white-brown, brown). Keeping them stretched out, grasp the connector and forcefully insert them. Make sure the wires are reaching the teeth at the bottom of the connector.
  • Check that the cables in your connector are in the correct order. Since once crimped, the connector cannot be reused. A badly crimped connector will therefore be useless
  • Then insert the connector into the RJ45 slot of your crimping pliers (without releasing the connector, to prevent the wires from pulling out). Tighten the clamp forcefully, release it, and re-tighten to be sure your termination is secure.
  • Repeat for the second end of the cable.

This is what you need to know about how to crimp a straight and crossover cable, also about the difference between these two types of cables. However, today there are equipment (Switch, box or routers) that automatically adapt the cables (straight or crossed). This equipment detects the nature of the cable, then uncrosses or crosses it as needed.

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  1. Hello, concerning the crossover cable, why not simply say that it is a cable where one of the connectors is T568A standard and the other is T568B standard? It's easier to remember than explaining that the pairs 1-2 and 3-6 must be reversed, right? 🙂

    1. It's all in the article. In addition, what is easy to remember or not depends on everyone. This is your point of view, Hi.

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