How to Crimp RJ45 Connector?

This article describes the RJ45 crimping method. The cable connector “RJ” stands for “Registered Jack”. The Registered Jacks are a standardized series of telecommunications and data networking connectors. They are typically associated with telephone and Ethernet connections. The most common RJ connectors include RJ-11 and RJ-45.

RJ45 connector and cable

The article discusses the main types of cables and RJ45 connectors.

RJ45 connector is commonly used for telephone lines and has eight positions and eight conductors. It is a standard connector used for wired Ethernet networking, including Cat5e, Cat 6, and Cat 7 cables.

The connectors have specific wiring configurations used for a specific purpose. Ethernet standards like 10BASE-T, 100BASE-TX, and 1000BASE-T for various networking applications use RJ45 connectors.

Crimping an RJ45 connector with an Ethernet cable, also known as a Cat5e or Cat6 cable, involves carefully wiring the connectors at both ends. These cables are commonly used for networking. Cables are prepared for required lengths or when repairing damaged cables.

Two types of Ethernet cables

Ethernet cables are used for communication in computer networks, and there are indeed two main types of Ethernet cables:

  1. Straight-through cable
  2. Crossover cable

Straight-through cables are used for connecting devices of different types, like a computer to a network switch.

Crossover cables, on the other hand, are used for connecting devices of the same type directly to each other, such as two computers. Choosing the right type of cable is essential to ensure proper communication in a network.

Straight-Through Cable

The most common type of Ethernet cable is a straight-through cable.

Straight-Through Cable

A straight-through connects devices with different functions in a network, such as connecting a computer to a hub, switch, or router.

In this cable type, the wire connections at one end of the cable match the wire connections at the other end. On one end of the cable, for instance, pin 1 will be connected to pin 1, on the other side, and so forth.

Straight-through cables are typically used to transmit data from a transmitter device (TX) to another device’s receiver (RX).

Crossover Cable

Crossover Cable

A crossover cable is employed to connect two devices of the same type, such as two switches or two computers. Connection is made to each other without the need for intermediate devices like a router or hub. Crossover cables are generally used to establish a direct network connection between two devices of the same kind.

In this cable, some of the wires are crossed between one end of the cable and the other. For example, pin 1 on one end is connected to pin 3 on the other end, and pin 2 on the one end is connected to pin 6 on the other end.

rj45 crimping tool

Materials and Tools Needed to Crimp RJ45 Connector:

  1. Cat5e or Cat6 Ethernet cable (typically unshielded twisted pair, UTP)
  2. RJ45 connectors (2 for each cable)
  3. RJ45 crimping tool
  4. Wire stripper
  5. Cable tester (optional)

The procedure RJ45 Crimping

Here is a step-by-step guide to preparing an RJ-45 connector.

Step 1

  • Start by stripping approximately 1.5 inches(4cm) of the outer jacket(the outermost layer) of the Ethernet cable using a stripper wire.


  • We will find four twisted pairs of wires inside the RJ45 cable, each color-coded. There, we find eight individual wires: white/orange, white/green, blue, white/blue, green, white/brown, and brown.
  • Carefully untwist and separate each of the four pairs while maintaining the twist within each pair to reduce interference.

Step 3

To create a standard Ethernet cable (T568B), arrange the wires in the following order from left to right when holding the RJ45 connector with the pins facing up and away

1. White/Orange
2. Orange
3. White/Green
4. Blue
5. White/Blue
6. Green
7. White/Brown
8. Brown

Step 4

Trim the wires so they are all of equal length, about 1.3 cm from the outer jacket. Ensure that the wires are neatly aligned in the specified order.

Step 5

Make sure each wire reaches the end of the connector by inserting it carefully into the RJ45 connector.

Double-check the wire order to ensure they match the T568B standard.

Step 6

Use a high-quality crimping tool to tighten the RJ 45 connector’s wires.

Put the RJ-45 connector into the crimping tool and press down firmly to crimp the RJ45 connector onto the wires. Ensure that the connector’s pins get into each wire’s insulation.

Repeat on the other end.

Follow the same procedure to crimp the RJ45 connector on the other end of the cable, ensuring that both ends have identical wiring arrangements.

Step 7

With a cable tester, verify that the cable is properly wired and functioning. Ensure all eight wires are connected correctly and there are no shorts or crossed wires.

Use cable ties or straps to bundle and secure the cable if desired. Even label it on both sides for clear understanding.

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