Useful Tips

How to crimp an RJ-45 cable correctly


Good day, dear visitors! I remembered here that I had not written about how to crimp a network cable and how it can be crimped. What is a network cable, I think you know. This is the cable through which you most likely get the Internet, connect a computer to a router or two computers directly, simply by connecting a network cable to the network cards of two computers.

And you probably know that a network cable is sold without connectors. Connectors, this is such a thing at the end of a network cable that connects to a network card, router, etc. Why is this? Can you imagine what holes would have to be drilled to push the connector :). And so, a network cable is laid and after that the RJ-45 connectors are crimped on it, everything is very convenient and thought out. Well, here we come to the fact that the network cable needs to be crimped, which means that you need to put the connector on the cable and fix it.

I just have a network cable, several RJ-45 connectors, a special tool and a phone for which I will photograph all this so that my instructions are understandable and you quickly learn how to crimp a twisted pair.

To crimp the network cable, we need:

  1. Himself network cable, immediately measure the required amount of cable.
  2. Connectors. Only two are needed for the idea, but I advise you to buy more, well, just in case :). They are not expensive, and you can buy at any computer store, in fact, like a cable.
  3. Crimping tool. There are several options, ideally you need to buy a special tool, crimper. Like the one in the photo above. I bought mine for 75 UAH. (300 rubles). If you do not have such a thing, then you can use a screwdriver, but I do not advise.
  4. If you squeeze a screwdriver, then you will need another ordinary knife, in order to strip the cable.

Well, let's get started.

Compress the network cable

There is another nuance, we need to decide which of the two options we will crimp the cable.

Straight - such a cable is suitable for connecting a computer to a router, for a regular Internet cable, etc. We can say that this is a standard.

Cross (crossover) - This option should be used when you want to make a cable to connect two computers directly. I wrote more about this in the article How to make (compress) a crossover ?.

Straight cable (circuit)

See also:

Cross cable (circuit)

We take the cable and remove the top insulation. Just stepping back from the beginning of the cable about two centimeters, we make an incision of the upper insulation, in a tool like mine, there is a special hole in which we insert the cable and simply scroll the crimper around the cable. Then remove the white insulation by simply pulling it off the cable.

Further we observe four pairs of twisted veins and a thread. Cut the thread, it will not be useful to us.

Now we unwind all the wiring so that they are one at a time. Hold them with your fingers and set them in the order we need, depending on which cable you are crimping. See the diagrams above.

When all the wires are set correctly, they can still be cut a little if they turned out to be very long, and even aligning them will not hurt. So when everything is ready, we very carefully and slowly begin to enter these wires into the connector. See that the wires enter the connector correctly, each in its own hole. After the cable is inserted into the connector, once again check the correct placement of the cores, then insert the connector into the crimper and squeeze the handles.

Everything, the cable is ready.

I hope that my article is clear and you were able to squeeze the network cable. If something is not clear, or does not work, then ask in the comments, we will figure it out.

What tools and items will be required

How to crimp a cable? Yes, it’s very simple, but first you need to understand what we need. And this:

    1. Not crimped cable (and crimped too, because it turns into elegant shorts without crimped appearance with one easy movement of scissors). You can buy in any computer store at a price of about 5-10 rubles per meter,
    2. A pair (as practice shows - better more) of RJ-45 connectors. They cost around 5 rubles apiece. They look like this:

  1. The knife is small (it is better not to use a full-fledged kitchen cleaver for cutting meat, -)). We need it to remove the outer insulation.
  2. "Crimping", i.e. what we will crimp. There are two options here:
      • Crimper. It costs about 500 rubles in the same stores. Allows easy and quick crimping of cables. Looks like that:

  • Ordinary screwdriver (slotted). In this case, an additional latch for connectors is often required. As it is possible to use the hands of a partner.

Note: in principle, some are still crimped with teeth; if a screwdriver is used, it is advisable to be careful. There were precedents.

How to crimp a cable - process and methods

First, remove the outer insulation.

Option 1. Purely Russian.
Using a knife, gently pushing, we carefully walk along the contour of our cable (if you press too hard, you will damage the core or accidentally cut off the cable floor).

Option 2. Thoughtful.
In the cable, as a rule, there is a special thread (usually white in color from kapron), we take it and pull along the cable. Thus, it will cut the outer insulation, and then you can cut off the excess with the same knife.

Option 3. The best.
Especially advanced most crimpers have long had a built-in blade for stripping insulation - just insert the cable into the hole, squeeze the tool handles and then remove the winding with your hands. Conveniently, evenly and the insulation is cut off, you can say, the tuft in the tuft.

Now our cable without insulation is 4 pairs of twisted strands and a nylon thread. You can immediately cut the thread. You do not need it. Next, we untangle the veins and try to straighten them if possible.

Now we need to determine what type of cable we will do, because how to compress the cable (in what way), and there are several ways.

Cable type or compression method

There are two of them:

  • Direct - to connect the network card port to the switch / hub.
  • Cross, (Crossover) - for connecting directly two network cards installed in computers, as well as for connecting some old models of hubs / switches

In most cases, using a straight crimping sequence is sufficient.

  • If you are not sure which type to use for you, then find out in those support of your provider in what order the wires should be,
  • If you want to connect 2 computers directly, then use the cross type,
    If you want to connect a computer to a hub / switch / router, then just use the direct type.

Straight cable crimp

Cross cable crimp pattern

So, after you have decided on the scheme, you need to build our cores (wiring) in one of the above positions. After this, it is necessary to align the cores so that they are as parallel and close to each other as possible, namely, so that neither the cores themselves nor their ends diverge anywhere.

After that, gently, smoothly, gently and slowly we enter the wires into the connector, carefully controlling the process, namely, making sure that the colors do not mess up or the two cores do not fit into one track.

Having successfully introduced the cores laid out and aligned in advance into both connectors, we put them (connectors) into the crimper and tightly hold the handles.

If you did everything correctly and carefully, then the wire is ready and now the question of how to compress the cable should not stand in front of you.

In the case of a screwdriver, everything is somewhat more complicated. We need to fix the connector somewhere and fix the wires so that when crimping the cores they do not come out of the connector. We take a screwdriver and push the yellow latches to the end (they must push through the insulation of the core in order to have a connection to the wire).

The difficulty is that you can drop the wire when you have already clamped the latch, or if the core has not reached the latch, and you have already sold it. Then you have to use another connector, because this one is broken.


These are the wires. So now, I hope you know how to crimp the RJ 45 cable (for and not only it).

In theory, the article is quite detailed and, if there is a desire, it is very easily implemented in life, but if you suddenly have any questions, then, as always, ask in the comments - I will be happy to help.

PS: For the existence of this article, special thanks to a friend of the project and a member of our team under the nickname “barn4k“.

Necessary equipment.

For work, you will definitely need the following tools and materials:

Cable. In another "network cable" or "internet cable". Correctly called "twisted pair", there are categories 5e or 6. Cable categories are more popular. cat.5e - because of its functionality. For almost all types of work, it will be enough for you. Attention!According to standardTIA / EIA-568-B the maximum long line of category 5e may be no more than 90m + 10% margin, that is, the actual recommended cable length should not exceed 100m. Depending on the manufacturer, the quality of the gasket, external electromagnetic interference, the possible signal transmission distance may vary.

Connectors Here you need the RJ-45 connectors (8P8C). Those who have little experience in crimping - crimping a twisted pair cable, we recommend stocking up at least 2 Rj45 “connectors”. If the store does not understand what you need, then ask the seller for another name for them - the 8P8C connector. The cost of 8P8C connectors at retail starts from 20-30 rubles per piece, when you buy a package of 100 pieces, you can save from 50% to 200%. Connectors are for category 5e and category 6 cable, the main difference is that the cable of the 6th category and higher has a 23AWG core cross section (diameter 0.573mm), which is significantly larger than the 5th category twisted pair cable with 24AWG (diameter 0.511 mm). RJ45 is also divided into 2 types: for unshielded UTP cable and shielded FTP cable. In appearance they are easy to distinguish, the second - FTP "shrouded" in a metallized shell. Here's what the connectors look like for category 5e:

RJ-45s are also divided by the method of cable entry: Without insertion - suitable only for single-core cable. As a rule, they are the most convenient and common. You saw them in the pictures above.

And there are connectors that allow you to insert a soft multicore cable, for this there is a special insert along with the cable. This is how they look

By the way, AWG is the American Wire Gauge System, which in Russian means "American wire gauge system." The most interesting thing is that the greater the value, the smaller the core diameter.

- Equipment. Ideally, it is more convenient to crimp with crimping pliers (they are also called simply “crimping” or, according to the original name, crimper), as well as a device for cutting the cable. Here is what the most common crimper models look like:

Also, for stripping the cable you need a stripper - in Russian Stripping. The word stripper, as you might guess, came from the English word Stripper - puller. Stripping piece. Strippers look like this:

It is very important to adjust the position of the blade during stripping by setting the required cutting diameter. The diameter of the insulation slice is selected in such a way that the blade does not touch the insulation of the cores. A good stripper cuts insulation in 1 turn. Having a stripper in your work is of course very good, but if you do not regularly do such a job, you can get by with a regular stationery knife. Most types of crimpers (crimps) have built-in strippers, they are not always convenient, their blade is not adjustable, but for irregular stripping of the cable they are quite suitable.

In total, 2 standards for crimping twisted pair are used in the world: TIA / EIA-568A and TIA / EIA-568B. They are almost identical, but they are easy to confuse, not only because of this. The catch is that the main difference between these standards lies in the colors of the pairs: 568A uses a green pair for information transmission, and orange for reception, and the 568B standard does everything in a mirror. That is, in 568B, information is transmitted through an orange pair, and a green pair receives information. It is the second option that is very often used in Russia. I use the 568A standard only in 3% of cases, as statistics show, so we will consider only the 568B twisted pair cable later.

Twisted pair crimping circuit.

Crimping is easy. But you need to know that the type of crimp is completely different for different types of devices. We have created a convenient infographic for you to explain in an accessible way which diagram is suitable for what.

Download crimping scheme (network cable) in high resolution (4961x2790px) for printing on a printer.

That's basically it. We told and showed all the main points and schemes of crimping twisted pair. If you use the material, do not forget to put a link to our website. Thank!

LAN network cable crimping schemes

There are two ways that you can make an Internet cable. Most likely you need the first method, direct crimping. Let's take a closer look.

1 If you need a cable to connect a laptop, computer, TV, or other equipment to a router or modem, then you need to make a cable according to this scheme. This is a direct crimp order. The easiest and most common way. Such a network cable, for example, comes with a router.

There are two crimping methods: T568A and T568B. I did according to the T568B scheme, which you can see below. It turns out that we crimp both connectors the same way.

2 The second way - cross, or cross. Such a cable is useful for connecting directly two computers (without a router).

I think you have decided on the scheme. You can read more about this in the article: twisted pair: what is it? Schemes and methods of crimping twisted pair. I will make a simple cable (direct crimp) according to the T568B scheme.

Crimp twisted pair without a tool (crimper)

If you have everything you need, you can begin to manufacture the cable. I will try to show everything as detailed as possible and step by step.

1 Remove the outer insulation from the twisted pair. Somewhere two centimeters. Lightly cut the insulation in a circle and pull it off. Just watch carefully so as not to damage the insulation of the wires themselves.

2 We straighten the wiring and set them to color. According to the scheme that you have chosen (photo above). It is advisable to expose them so that they do not intertwine. I got it like this:

3 Next we need to trim the wiring. Leave about a centimeter. I will do this with special wire cutters. As I wrote above, you can trim them with scissors, or a knife.

4 Check whether the wiring is correctly set according to the scheme, and insert them into the connector. The RJ-45 connector itself is held latched by itself. As in the photo below.

We insert the wiring all the way. They should go completely and abut against the front wall of the connector.

5 Once again, we check whether the twisted pair has entered the connector correctly, and proceed to crimping. We take our screwdriver (maybe you have something else), and in turn press the contacts. Watch carefully, do not hurt your hand!

Contacts need to be pressed strongly. So that they pierce the cable. The contact itself should not just align with the connector housing, but be slightly recessed into the housing. Occupation is not the easiest. When I squeezed the cable with a screwdriver, it was hardly inserted into the LAN port of the router (but it was already working), after which I still squeezed the contacts with a screwdriver.

After I squeezed each contact, I still clicked on the cable clamp. He simply presses inward and presses the outer insulation.

All is ready. We do the same on the other side of the cable. I got it like this:

As you can see, the contacts themselves are slightly damaged by a screwdriver. When crimping with a crimper, there is no such damage.

I checked the cable by connecting a laptop to the router with it. The Internet has appeared on the laptop, which means that everything turned out and works. I managed to make a network cable the first time. Even without a special tool, using a conventional knife and screwdriver. I hope you did the same.

What to do if the network cable does not work?

Maybe so. But I would not be in a hurry to immediately dump everything on the cable. It is possible that the problem is in the router, computer, or other device that you are connecting. Need to check.

  • Connect the other device using the cable manufactured. If possible, check the devices by connecting them with another cable. To make sure that it is in the network cable that we just crimped.
  • Be sure to carefully check the sequence of wires in the connector in accordance with the diagram.
  • If you mixed up the sequence of wires, then bite off the connector and redo it.
  • If everything is according to the scheme, then take a screwdriver, and squeeze the contacts on the connector. It is possible that there is no contact.

That's all. Write in the comments about your results, ask questions, and share tips. Good luck to all!