RJ45 Connector Wiring: Complete Guide

RJ45 Connector

One reason why communication and data services have exploded all over the world is the use of modular electronic connectors. One of the most widely used types in the modular family of devices is RJ45 connector.

Continue reading for more information about RJ45’s various types, features, and applications.

What Is An RJ45 Connector?

When used with a cable, an RJ45 connector is a popular modular interconnection device that connects different electronic systems and devices to the internet.

The RJ label was created in 1976 when the FCC classified the various connectors created using this system under the Registered Jack (RJ) system. This was carried out in order to guarantee that consumer electronics and phone company hardware would work together. The physical connector, wiring schemes, and signal specifics are all covered by the RJ system.

Like all modular connectors, RJ45 devices have metal contacts that are spaced apart by insulating plastic channels. The connectors lock in place with a tab, making them secure but also releasable, and the channels fit into a corresponding socket. RJ45 devices can accommodate 4 twisted wire pairs because they have 8 internal pins and wire positions for handling power or signals.

An RJ45’s 8-pin configuration is comparable to that of 8P8C connectors, but real RJ45 connectors also have a tab that only permits insertion of the device into a compatible socket in one direction, preventing improper wiring connections. A particular kind of 8P8C connector is the RJ45. The majority of 8P8C connectors are commonly referred to as RJ45, but this is not entirely accurate. 8P8C connectors can be plugged into RJ45 sockets, but the opposite is not possible.

Read More: RJ12 Vs. RJ11 Vs. RJ45 Connector

Various Types Of RJ45 Connectors

Depending on the application, different RJ45 connector types are offered. These include:

  • Standard – 8 position, 8 connection, non-shielded.
  • Shielded – internally shielded connectors that incorporate a connection to shielded cables. RJ48 is another possible name for it.
  • Ruggedized – include various external parts to protect the device from harsh environments. Also known as Hi-Rel, a shortened form of high reliability.
  • 10 Pin RJ45 – 10 pin connector used where all serial lines are needed, as with a T1 line.
  • Miniaturized – smaller footprint version of standard RJ45.
RJ45 Connector

RJ45 Features And Capabilities

RJ45 connectors incorporate the fundamental characteristics of modular connectors, including low cost, solderless connector and wiring assembly, quick production of customized cables, straightforward insertion and removal, simple field assembly with minimal tooling, and the ability to design cables on-site. In order to be used in a variety of applications, sockets (or receptacles) can also have a vertical or horizontal orientation.

In addition, RJ45 connectors have the aforementioned orientation tab to prevent improper wiring. Additionally, because of their 8-pin design, they can be used in applications that require more demanding and data-intensive functions.

Additional available features can include:

  • Shielding – to cancel the effects of EMI/RFI
  • Keying – to ensure proper insertion
  • Various mounting capabilities – to allow for panel, board, surface or through hole methods
  • Displays and indicators – to indicate connection status
  • Integrated magnetics – to allow for better shielding plus current protection
  • Hi-Rel – to provide protection for the hardware and the connection

RJ45 Connector Applications

RJ45 connectors with Cat5 or Cat6 cabling are the industry standard for connectivity in networks, peripherals, and telecommunications when designing Ethernet capability into a system. This interconnection system is now usable for purposes outside of office or home networking thanks to the addition of features and capabilities, such as faster speed and greater ruggedness, to the RJ45 product line.

The introduction of the EtherCAT protocol has resulted in increased usage both inside factories and outside of them. Some of the newer applications that use RJ45 technology include:

  • Factory Automation
  • Industrial Process Control
  • Industrial Robotics (fabrication and assembly)
  • Test and Measurement Systems
  • Quality Control Systems
  • Voice Over Internet Protocol (VOIP) Systems and Devices
  • Internet of Things (IOT) Network Devices

RJ45 & Ethernet

Ethernet is just a way of physically connecting computers and other devices. It permits data transmission over LANs and WANs and connects them via cables so that they can talk to one another.

The IEEE (Institute of Electrical and Electronic Engineers) created the Ethernet standard (IEEE 802.3), which is currently the most widely used LAN technology worldwide. It specifies the specifications for setting up an Ethernet network (connections), the quantity of conductors needed for a connection, the anticipated performance, and a structure for data transmission.

The balance that Ethernet technology provides between simplicity of installation, speed, cost, and broad network protocol support is the reason for its widespread adoption. The standard hardware for setting up a network is RJ45 connectors.

RJ45 Technical Specifics

Depending on how involved you are in the design process, there are some technical considerations if you are creating a device that will connect to an Ethernet network and utilize RJ45 connectors.

At the board level, EMI reduction, signal integrity preservation, and electrical signal isolation are priorities. The length and location of traces on the board need to be considered without getting into the specifics of circuit design. Keeping magnetics as close to the RJ45 connections as possible should also be isolated. The best RJ45 connectors for EMI reduction would ideally have integrated magnetics, which is covered in more detail below. The actual placement of the connectors on the board needs to be taken into account as well.

Including panel, board, through hole, and surface mount, RJ45 connectors are available for the majority of common component mounting techniques.

How to Terminate With An RJ45 Connector?

  • STEP 1: Trim the cable end you’re terminating with a crimping tool to make sure the ends of the conducting wires are even.
  • STEP 2: Use a modular crimping tool or a cable stripper to remove about 1 inch of the cable’s jacket while being careful not to harm the inner conducting wires.
  • STEP 3: To create 8 individual wires, first unwind each pair of the 4 twisted wire pairs. To ensure proper insertion into the connector, the wires should be as flat as possible. They also need to be very straight.
  • STEP 4: Holding the cable so that the wire ends are pointed away from you. Place the wires in a flat, side-by-side ribbon formation, going from left to right, in the following order: white/orange, solid orange, white/green, solid blue, white/blue, solid green, white/brown, solid brown.
  • STEP 5: Carefully push the flattened, arranged wires into the RJ45 connector, pushing through until the wire ends emerge from the pins, while holding the connector so that the plug-clip side is facing down and the pins are facing away from you. Additionally, insert as much of the cable jacket as you can into the connector to ensure a strong connection.
  • STEP 6: Verify the order of the wire ends coming out of the connector’s pin side; if necessary, remove them from the connector, arrange them correctly, and then re-insert. Keep in mind that once the connector is crimped to the cable, it is there for good. After termination, if you discover a wire order error, you must cut the connector off and start over.
  • STEP 7: In your crimping tool’s RJ45 slot, place the prepared connector/cable assembly. Squeeze the handles of the crimper tightly together until you run out of room. Release the handles and repeat this step to ensure
  • STEP 8: If your crimper doesn’t automatically trim the wire ends after termination, carefully cut the wire ends to make them as flush with the surface of the connector as you can. The quality of your final plug-in connection will depend on how closely the wire ends are trimmed.
  • STEP 9: Continue the process on the other end of your cable after the initial termination is finished.


The system of modular connectors was initially created to upgrade an outdated and labor-intensive telephone interconnect procedure. In this system, RJ45 connectors were added to address the interconnectivity issues that can arise when using the Ethernet protocol.

RJ45 devices offer easy design-in, quick and easy installation, breadth of product, and user accessibility, just like other modular connectors. They are widely used for home and office network applications and are gaining popularity in harsh environments and on factory floors.

Read More