RJ45 twisted pair cable pinout: connection diagrams and crimping rules

Power cords, like other technical accessories, fail at the most inopportune moments.But if you have crimping skills, a new connector and the necessary tools, the problem can be fixed in a few minutes.

Another difficulty is that Internet cables are multi-core, and a 4-pair cable is used more often than others. Therefore, in addition to practical skills, you will need the correct RJ-45 pinout - a suitable color scheme. If you make a mistake with the distribution of conductors, you can be left without the Internet.

In this material we will talk about the features of twisted pair cables and provide several cable crimping diagrams.

Features of twisted pair

An ordinary electrical wire, for example, VVGng 3*2.5, consists of three cores. This can be understood by removing the top polymer shell. A twisted pair (in other words, a network wire, an RJ-45 cable) can consist of one pair of wires or several.

Usually, ready-made patch cords are used - sections of cable of standard length (on average from 0.3 m to 30 m). On both sides, the factory cord is crimped with connectors - small 8-pin plugs that can be inserted into internet socket, connector on the router, PC, TV and other equipment.

For home use, they offer single- and multi-core cables, but the latter are used more often. Twisted pair cables are sold in coils and sold by the meter

But it is also useful to have a piece of cable that has not been pre-crimped: for example, sometimes you need to pass the cable through a small, no more than 5 mm, hole in the wall. In this case, crimping is done after installation.

Characteristics of the RJ-45 Internet cable that may be useful:

The bandwidth of an RJ-45 cable is determined by category. There are 10 categories in total - 7 main and 3 subcategories. The first four categories are considered obsolete because they do not support the required data transfer speed.

The most popular is category 5e, which can consist of 2 or 4 pairs of conductors. This is a more flexible and thinner cable than its predecessor - Category 5 Class D

Almost all the necessary information about the cable is located on the outer shell. The marking of different manufacturers differs, but such characteristics as category, brand code, shielding method (or lack thereof), number of pairs, and standard are usually indicated.

You can read about other types of cables that are used to connect to the Internet in our another article.

Standard crimping patterns

Pinout of twisted pair cables and installation of connectors falls under the regulations of the international standard EIA/TIA-568, which describes the procedure and rules for switching intra-apartment networks. The choice of crimping scheme depends on the purpose of the cable and network characteristics - for example, on bandwidth.

Thanks to the transparent body of the connector, it is clear that the wires are arranged in a certain order, and not at random. If you mix up a pair of conductors, the commutation will be disrupted

Both types of cables - from 4 or 8 cores - can be crimped directly or crosswise, as well as using type A or B.

Option #1 – straight 8-conductor cable

The direct crimping method is used when you need to connect two devices:

• on one side - PC, printer, copy machine, TV;
• on the other hand - a router, a switch.

A special feature of this method is the same crimping of both ends of the wire, for the same reason the method is called direct.

There are two interchangeable types - A and B. For Russia, the use of type B is typical.

Pinout diagram of an 8-wire cable for direct connection of a computer to a switching device (HAB, SWITCH). In the first position is an orange-white vein

In the USA and Europe, on the contrary, type A crimping is considered more common.

Type A differs from type B in the arrangement of conductors located in positions 1, 2, 3 and 6, that is, white-green/green swap places with white-orange/orange

You can perform crimping in both ways, the quality of data transmission will not suffer from this. The main thing is to observe the order of the veins.

Option #2 – 8-wire crossover

Cross crimping is used less frequently than straight crimping. It is necessary if you need to connect two desktop computers, two laptops or two switching devices - hubs.

Crossover is used less and less, since modern equipment can automatically determine the type of cable and, if necessary, change the signal supply. The new technology is called auto-MDIX. However, some home devices have been working properly for years, there is no point in changing them, so cross-crimping can also be useful.

When cross crimping, it is possible to use types A and B.

Crossover circuit designed for equipment of high-speed networks (up to 10 gbit/s), made according to type B. All 8 conductors are involved, the signal passes in both directions

To use type A, you need to change the same 4 positions: 1, 2, 3 and 6 - white-green/green conductors with white-orange/orange.

For a network with a lower data transfer rate of 10-100 mbit/s, there are different rules:

Type B circuit.Two pairs of twists - white-blue/blue and white-brown/brown - are connected directly, without crossing

The scheme of standard A completely repeats B, but in a mirror image.

Option #3 - straight 4-wire cable

If for high-speed information transfer (for example, Ethernet 100BASE-TX or 1000BASE-T) an 8-wire cable is required, then for “slow” networks (10-100BASE-T) a 4-wire cable is sufficient.

Scheme for crimping a power cord into 4 cores. Out of habit, two pairs of conductors are used - white-orange/orange and white-green/green, but sometimes two other pairs are used

If the cable fails due to a short circuit or break, you can use free conductors instead of used ones. To do this, cut off the connectors and crimp two pairs of other wires.

Option #4 – 4-wire crossover

When cross-crimping, 2 pairs are also used, and you can choose twists of any color. Traditionally, green and orange conductors are often chosen.

The crossover crimping circuit for a 4-wire cable is used extremely rarely, mainly in home networks, if you need to connect two old computers. The choice of core color does not affect the quality of data transmission.

How to crimp an RJ-45 cable correctly?

Exist various ways to crimp an RJ-45 cable, among which there is even crimping of the connector without special pliers, using an ordinary flat-head screwdriver.

But we will look at how to competently make a reliable and functional working patch cord, the characteristics of which are no different from purchased models.

Selection and preparation of tools

Having a set of special tools on hand makes crimping a patch cable much easier.Of course, you will have to allocate money to purchase a crimper, stripper, tester or crosser, but if you buy a quality tool, it will last for years.

To properly secure the connectors to the cable you will need:

The main tools listed are pliers and a tester - this is the minimum set required for correct pinout and crimping of twisted pair cables.

When buying pliers, you need to check their quality and it is advisable to test the tool first. Some crimpers are equipped with blades that can be used to strip the veins.

Step-by-step instructions for crimping

To make a patch cord, you will need to prepare materials - cable and connectors, arm yourself with a tool and choose a pinout diagram depending on what devices the finished cord will connect.

List of materials:

• a piece of twisted pair is no longer than 100 m - according to the Ethernet pinout, this is the maximum length of standards for household use;
• for one cable - two RJ-45 connectors (their marking is 8Р8С);
• set of tools – crimper, stripper, tester.

Most often, a cable is required to connect a PC to a network device, so we remember the direct crimping diagram, and for reliability, we simply put it in a visible place so that it is in front of our eyes at the time of distribution of the wires.

A ready-made color diagram can be found on the Internet and printed on a piece of paper - visual perception promotes memorization, and it will no longer be needed in the future

Do not forget that types A and B differ only in the location of the orange and green twists; both options can be used.

Step-by-step instruction:

• Step 1 – We cut a piece of cable according to the meter, without reserve, but of sufficient length with wire cutters or crimper blades.
• Step 2 – We retreat from the end 2-4 cm, do stripper make a circular cut on the outer insulation, and then carefully remove it.
• Step 3 – The conductors are twisted in pairs, so before crimping we untwist all the pairs, straighten the cores and distribute them according to the chosen pattern.In addition to the conductors, a nylon thread is hidden under the shell - you just need to pull it back.
• Step 4 – We trim the conductors. To do this, we retreat 1.0-1.3 cm from the edge of the outer insulation and cut off the wires with wire cutters strictly perpendicular to the axis of the twisted pair. We make sure that the multi-colored tips are the same length.
• Step 5 – Insert the conductors into the connector and push them all the way.
• Step 6 – We perform crimping: insert the connector with conductors into the desired connector of the crimper (marked 8P) and squeeze the handles of the pliers. You can hear a click.
• Step 7 – We check the reliability of the fastening - lightly pull the cable, as if trying to get the conductors out of the connector. When crimped correctly, the wires sit firmly.
• Step 8 – We test the finished patch cord for serviceability. We insert the connectors into the sockets of the tester, turn on the device and monitor the indication. If everything is in order, the lights will light up green in pairs. If there is no indication or the red light comes on, the procedure will need to be repeated.

The hand gets filled quickly - after several independent crimps. The crimping skill will come in handy when moving to a new apartment, where network wires are hidden in baseboards or sewn into the walls and connected to computer sockets.

There is no need to worry that the cable is too long or short - you can always crimp the patch cord to the desired length. If the power cable is suddenly chewed by a dog or it is simply bent, you can quickly make repairs.

You may also be interested in seeing how you can connect twisted pair cables to each other, to do this, go to this link.

Conclusions and useful video on the topic

Short video instruction:

Cable crimping of categories 5 and 6, what is the difference:

When there are no professional tools at hand:

Knowing the pinout of the twisted pair, you can quickly crimp the patch cord depending on its purpose. This skill is useful for any user of personal equipment, as it allows you to quickly respond to a signal break in the local network - completely replace the network cable or make minor repairs.

Do you have any questions about twisted pair cable pinouts? Please ask them in the comments section, and we will try to explain any unclear points as clearly as possible.