How to properly crimp RJ-45 connectors (category 5, twisted pair). Direct wiring. Cross wiring
1. Direct crimping procedure for the twisted pair cable leading from the workstation to the hub.
2. Cross-link (crossover, crossover) order of twisted pair crimping.
It is used when it is necessary to connect 2 hubs that do not have uplink/normal switching, as well as for direct connection of 2 computers.
Options for wiring (cutting) eight-core twisted pair
Four wires (orange and green pair) are used for 100Base-T Ethernet, and the remaining four are reserved for Gigabit Ethernet (1000Base-T). There are two wiring options 568A or 568B, the choice is yours. The second option (568B) is most often used. The most important thing is that one of the options is used throughout the network.
Appearance of the RJ-45 connector with pin numbering
The cable layout for connecting a computer to network equipment (patch cord) is presented in the table; the figures to the right of the table show the appearance of the cable prepared for insertion into the connector (both connectors are crimped in the same way):
The cable layout for connecting the network cards of two computers directly differs only in that at one end of the cable the green and orange pairs are swapped. Simply put, we get a cable with one connector is crimped according to option 586A, and the second according to option 586B. This cable is called a crossover or null-hub cable. The same wiring is used for cascading (connecting) hubs. In table form, this option looks like this:
Two computers can be connected using the wiring shown in the table below, but it is much more difficult to remember, so I present this option only for the sake of completeness of the review of the issue.
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.
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.
Typically, 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 the 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:
Image gallery
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.
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.
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.
RJ 45 or “Twisted Pair” is a type of wire consisting of four or eight thin wires, in pairs twisted between themselves. This type of cable is used for associations computers to a local network or connection to Internet. In some cases, twisted pair cable can be used for connections any peripheral devices (such as printers) to the computer.
Despite the presence of more advanced and high-quality technologies ( optical fiber, wireless communication channels), twisted pair is still used due to the low price of cable and related equipment (network cards, routers), as well as the high you just deployment of a local network and protection from external interference.
How to crimp a cable with an RJ 45 connector
Before you start crimping, you need to prepare all the necessary tools. In addition to the cable you will need : crimping pliers and special connectorsR.J. 45 .
From the wire is necessary take off external insulation (there is no need to touch the internal one), then in the correct order (depending on the crimping pattern) arrange wires in the connector. Having located all the wires inside the connector, you need to check their correct placement and squeeze cable using pre-prepared pliers. 
Crimping schemes
Direct scheme used to connect network devices of different types (for example, a computer and a router), as well as for associations two hubs or routers into one local network. This crimping scheme is the most frequently used on local networks.
The procedure for crimping an eight-core cable used in gigabit local networks, the following: 
In twisted pair cables used in local networks operating at speeds of 100 Mbit/s, the following direct crimping order is used: 
Cross(reverse) circuit is needed to connect two computers directly, without the use of hubs or switches. Gigabit A twisted pair crossover type is crimped as follows: 
Reverse wire diagram for local network operating at speed 100 Mbit/s.
To connect other devices, such as network printers, IP cameras and other similar devices, the crimping diagram is usually written in the instructions for the connected equipment.
Crimping a two-pair cable
To connect via one cable two devices use two-pair cable. Those. one cable branches at both ends and is crimped with two connectors.
The diagram below shows the principle of crimping in this way. Two pairs are inserted into one connector (use 1, 2, 3, 6), remaining pairs are inserted into the second connector (use 4, 5, 7, 8 respectively)
A two-pair RJ 45 cannot be used in gigabit networks or for cross crimp (they will require all eight cores). In the direct scheme, everything is quite standard. 
How to extend the cable
Not in all cases, the available twisted pair is enough to connect the necessary devices. In this case it may be necessary build-up wire in any way in order to lengthen it.
The easiest way to extend a cable is to use a special joyner RJ 45. This device is a regular adapter from one RJ-45 connector to another. To connect, you will need two pre-crimped wires and the joyner itself.
Advantages this method of extending the wire: simplicity connections of all elements, low price, quite high reliability(there is simply nothing to break).
Flaws: slight losses in connection stability and speed are possible; not all the necessary tools may be at hand.
For the highest quality wire extension, it is better to use router. This will allow you to get the highest quality and stable connection without any signal loss and reduction in network speed. Using this method of cable extension in reverse increases signal stability and reduces packet loss.
TO shortcomings this connection method can be attributed sufficiently high price(you will need to purchase a router). Also, do not forget that to connect you will need an outlet or the use of POE (power supply via twisted pair), in addition, the router may break down at the most inopportune moment.
Categorically not recommended for use twist. Even if you twist the wires perfectly, you will not be able to avoid signal loss and many other problems with this cable extension method.
The only one advantage twist is its price - it’s practically for free, otherwise this method of extending the wire is no good.
Twisting can only be used as a temporary option when the necessary tools or equipment for something better are not at hand. In this case, you should adhere to the following recommendations:
- It is advisable not to use twisting with wires made from different metals(for example, connecting aluminum and copper wires in this way). This will lead to strong heating and oxidation of the metal, as well as other undesirable problems;
- Places of twisting should be carefully isolate, this will at least slightly protect the connections from external interference and other difficulties.
The 8P8C modular connector, nicknamed “RJ45,” when used on an Ethrnet network, is crimped according to the TIA/EIA-568 standard.
Two pinout options have been developed - “A” and “B”. In Russia, there has been a tradition of connecting plugs and sockets exclusively according to the “B” pinout.
In everyday life, we encounter low-speed networks - up to 100 Mbit/s. For such speeds, four cores are enough. ▼
For reasons of economy, low-speed networks usually use a 4-core cable.
This cable has only two pairs - orange and blue. Please note - a couple not green, but it switches to those pins that are assigned to the green pair in the classic pinout. ▼
8P8C sockets
The numbering of contacts on socket blocks is not regulated by the standard. Each manufacturer places the contacts on the pads in a random order.
But it should be noted that the correspondence “pin number - wire color” is of course standard: 1 - white-orange, 2 - orange, etc. But where on the block contact No. 1 is located, and where No. 2 is located - depends on the specific model. If the cheat sheet comes off and is lost, all that remains is to look for an outlet of the same model to find out how to unplug it.
Most often I had to deal with the following pin arrangement on the patch block. ▼
"A" and "B"
Quite natural question: Why are there two pinout options - A and B?
Answer: Previously, cables were used that were crimped at one end along “A” and at the other end at “B”. These are so-called crossover cables. Such cables were required to connect two hierarchically equivalent network elements, for example, two switches or two PCs. In turn, the connection of a slave element with a superior one (for example, a PC with a server) was and is carried out with a cable crimped equally on both sides - A-A or B-B.
In modern practice, the need for crossover cables has disappeared. All network elements are connected by patch cords, crimped B-B.
Types of twisted pair
| Common name | Designation according to ISO/IEC 11801 | General screen | Screen for couples |
|---|---|---|---|
| UTP | U/UTP | No | No |
| STP, ScTP, PiMF | U/FTP | No | foil |
| FTP, STP, ScTP | F/UTP | foil | No |
| STP, ScTP | S/UTP | braid | No |
| SFTP, S-FTP, STP | SF/UTP | braid, foil | No |
| FFTP | F/FTP | foil | foil |
| SSTP, SFTP, STP PiMF | S/FTP | braid | foil |
| SSTP, SFTP | SF/FTP | braid, foil | foil |
The letter code before the slash indicates the type of overall shielding for the entire cable, the code after the slash indicates the type of individual shielding for each twisted pair:
U- U nshielded, no screen
F- F oil, foil
S- B raided screening, braided wire (outer screen only)
TP- T wisted P air, twisted pair
TQ - individual screen for two twisted pairs (4 wires) ▼
Twisted pair is manufactured in two modifications:
- with a single-core (solid) conductor
- with stranded conductor
In cases where the cable is subject to vibration or frequent touch (for example, a patch cord), it is necessary to use stranded wire. It is more durable and is not subject to quick breaking of wires.
There are cables not with solid copper, but with copper-plated cores - you can’t take this one.
If the cable is long and high noise immunity is required, S/FTP is used with a screen on each pair and a common shield covering it all from the outside. In this case, it is better to take metal connectors, or RJ-45 FTP in a metal shell.
Connector selection
The connectors must match the wire type! ▼
The correct choice of connector for a particular type of wire is extremely important. A suitable connector will provide the maximum number of points of reliable contact and will not damage the conductor. ▼
Platinum Tools® EZ-RJ45® Through Connectors make crimping twisted pair cables much easier. The twisted-pair cores do not rest against the end of such a connector, but go out, so there is no need to measure the cable strip and trim the cores before crimping. After crimping, the excess is simply cut off. Available on AliExpress at a price of 800 rubles per hundred (2017). ▼
If the cable has to be reconnected frequently, the latch on the plug breaks. I recommend using durable connectors with an elastic lock.
An interesting new product is Field-Mountable reusable connectors produced by BTR and R&M. No special tools required. I haven’t found it on sale for Russia yet. I think the price for such connectors will be outrageous.
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Twisted Pair Splicing
Troubleshooting a broken twisted pair cable in accordance with technical requirements carried out either by completely replacing the cable, or by crimping the ends and connecting them through the so-called. "barrel" -
The TIA/EIA 568-A standard, which was ratified in 1995, was replaced by the TIA/EIA 568-B standard in 2002 and has since been updated. Both standards specify the T-568A and T-568B outputs to use unshielded twisted pair cable and RJ-45 connectors for Ethernet connections. Both T-568A and T-568B standards are the most commonly used in Ethernet connections. The prefix RJ stands for Registered Jacks. RJ-11 is a 6-position, 4-wire jack used in telephone wiring, while RJ-45 is an 8-position, 8-wire jack used in 10BaseT and 100BaseT ethernet wiring.
RJ45 connector pinout
The RJ45 connector is commonly used to connect network cards with hubs to 10base-T and 100Base-TX cables in a network. RJ45 is a standard type of physical connector for network cables. The RJ45 connector is a modular 8-position, 8-pin connector used to connect computers on LANs with hubs. On network cards, pair 1-2 is the transmitter, and pair 3-6 is the receiver. The remaining two pairs are not used. Crossover cables are used to connect TX+ to RX+ and TX - to RX-. Unused pins are typically connected in a straight line, either straight or crosswise. They were initially used as a telephone-only standard, but were later applied to high-speed modems and other computer networks.
An RJ-45 data cable contains 4 pairs of wires, each of which consists of a solid colored wire and a strip of the same color. There are two standards for the RJ-45 connector: T-568A and T-568B. Although there are 4 pairs of wires, 10BaseT/100BaseT Ethernet only uses 2 pairs: orange and green. The remaining two colors (blue and brown) can be used for a second Ethernet line or for telephone connections. Two wiring standards are used to create a crossover cable (T-568A on one end and T-568B on the other end) or a straight cable (T-568B or T-568A on both ends).
Below are instructions for crimping RJ-45 connectors onto a cable.
T-568A color scheme
1 White-green.
2 Green.
3 White-orange.
4 Blue.
5 White and blue.
6 Orange.
7 White-brown.
8 Brown.
T-568B color scheme
1 White-orange.
2 Orange.
3 White-green.
4 Blue.
5 White and blue.
6 Green.
7 White-brown.
8 Brown.
The pinout is also duplicated in the picture below.
How to crimp a twisted pair of 8 cores
We will need a crimper, rj45 connector, and twisted pair cable, scissors.
Step 1: Remove the outer sheath at the end of the cable approximately 2.5 cm from the edge. Next, we unwind the twisted wires and remove all unnecessary ones.
Step 2: Pinch the wires between your fingers and straighten them. We sort the wires in the correct order as described above.
Step 3: Shorten the wires so that the wires stick out approximately 1.2-1.4 cm from the edge of the insulation. Use scissors to make a straight cut along all 8 wires.
Step 4: Carefully insert all 8 wires into the RJ-45 connector as far as possible, making sure they remain aligned and each color goes into the appropriate channel.
Step 5: Insert the wires into the rj45 connector all the way, check the sequence of the wires. Next, insert the connector into the crimper, into the “P8” socket and crimp the connector until it clicks.
Learn more about end-to-end and cross-connections
T-568A and T-568B are two wiring standards for the RJ-45 data cable specified in the TIA/EIA-568-A wiring standards document. The difference between them is the location of the orange and green wires. It is preferable to connect to T-568B standards, since this standard is very popular and widespread.
To create a straight-through cable, you need to use either T-568A or T-568B on both ends of the cable. To create a crossover cable, you can connect a T-568A on one end and a T-568B on the other end of the cable.
Straight-through cables are used when connecting data termination equipment (DTE) to communications equipment (DCE), such as computers and routers, modems (gateways), or hubs (Ethernet switches). Crossover cables are used when connecting DTE to DTE or DCE to DCE equipment such as a computer and a router. Or a gateway to hub connections.
To connect two computers without a hub, use a crossover cable. A crossover cable is also used to connect a router to a computer or an Ethernet switch (hub) to another Ethernet switch without an uplink. Most Ethernet switches today provide an uplink port that prevents a crossover cable from being used to daisy-chain another Ethernet switch. Wired cables are used to connect a computer to an Ethernet switch or a router to an Ethernet switch.
