What Is an RJ-45 Connector?

A registered jack 45 (RJ-45) is the most common connector in wired networks. Understanding the basics of these connectors is a must for anyone working with Ethernet or LAN networks.

RJ-45 connectors are the industry standard for creating stable, high-speed network connections. Knowing how they work, how to wire them, and the different types available is essential for engineers, IT professionals, and DIY enthusiasts.

Join us as we explore RJ-45 connectors, how to wire them, and the various options available—such as shielded and Cat6 connectors. This guide will help you make informed choices when sourcing parts through Octopart's platform.

What an RJ-45 Connector Is Used For

An RJ-45 connector is a standardized interface used for network cabling, primarily in Ethernet networks. Often referred to as an Ethernet connector or LAN connector, the RJ-45 is an 8-pin modular connector designed to connect computers, routers, and switches within a network. While you may commonly see it in home and office settings, it's also used extensively in industrial environments requiring reliable, wired connections.

What RJ-45 Stands For

The term "RJ" stands for "registered jack," and the number "45" identifies the specific interface standard. The connector is typically used with twisted-pair cables, most commonly Cat5, Cat6, or Cat6a cables, to deliver high-speed data transmission. When connected to an Ethernet port, an RJ-45 connector provides the physical link between your device and the network, allowing the transfer of data over long distances with minimal interference.

Types of RJ-45 Connectors

Not all RJ-45 connectors are created equal. Depending on your project's needs, you might encounter various types, each with features that suit a particular environment or application. Below, we'll take a look at some of the most common types.

1. RJ-45 Female Connector

The RJ-45 female connector is designed to receive an RJ-45 male plug, typically on Ethernet cables. These connectors are often used in wall outlets, patch panels, or networking hardware like switches and routers. They are available in panel-mount versions and PCB-mount versions.

2. Shielded RJ-45 Connector

For environments where electromagnetic interference (EMI) is a concern, the shielded RJ-45 connector is the go-to choice. These connectors feature additional shielding to protect the signal from external noise, making them ideal for use in industrial settings, manufacturing plants, or any area with high levels of electrical interference. Shielded RJ-45 connectors ensure more reliable data transmission and reduced signal degradation.

3. Cat6 and Cat6a Connectors

As data speeds increase, the demand for more advanced cabling solutions grows. Cat6 and 6a connectors are engineered to handle higher bandwidth and faster speeds than older Cat5e connectors. While a Cat6 connector supports speeds of up to 10Gbps over shorter distances, a Cat6a connector goes even further, offering improved performance with less crosstalk and support for higher speeds over longer distances. These connectors are ideal for modern high-speed networks, data centers, and enterprise environments.

RJ-45 Connector Wiring & Color Codes

Once you understand the basic wiring schemes and color codes, wiring an RJ-45 connector becomes straightforward. Proper wiring is essential to ensure data is transmitted accurately and efficiently between devices. Let's break down the wiring and color coding of these connectors.

How to Wire an RJ-45 Connector

When wiring an RJ-45 connector, there are two standard schemes to follow: T568A and T568B. Each is used for different purposes, but the main difference lies in how the wires are paired. Regardless of the scheme you use, you must ensure the same wiring pattern is followed on both ends of the cable to maintain a consistent signal.

• Strip the cable: Begin by stripping about one inch of the Ethernet cable's outer jacket to expose the twisted pairs of wires inside.
• Untwist the wire pairs: Carefully untwist the pairs of wires, straightening them out for easier alignment.
• Arrange the wires: Depending on whether you're using the T568A or T568B scheme, arrange the wires in the correct order. (See below for details.)
• Insert the wires into the connector: Align the wires according to the color code, then carefully insert them into the RJ-45 connector, ensuring each wire is fully seated.
• Crimp the connector: Using a crimping tool, secure the connector by compressing the metal pins onto the wires and locking them in place.

For most standard networking setups, the T568B wiring scheme is used, but both standards are acceptable as long as the same wiring pattern is followed on both ends. 

RJ-45 Connector Color Codes: T568B Wiring Scheme

Below is the standard color code for the T568B wiring scheme, which is widely used in modern Ethernet networks:

• Pin 1: White/Orange
• Pin 2: Orange
• Pin 3: White/Green
• Pin 4: Blue
• Pin 5: White/Blue
• Pin 6: Green
• Pin 7: White/Brown
• Pin 8: Brown

RJ-45 Connector Color Codes: T568A Wiring Scheme

The T568A wiring scheme is used in residential networks and some older installations. The color code for the T568A wiring scheme is:

• Pin 1: White/Green
• Pin 2: Green
• Pin 3: White/Orange
• Pin 4: Blue
• Pin 5: White/Blue
• Pin 6: Orange
• Pin 7: White/Brown
• Pin 8: Brown

Using the proper color codes ensures that each pin is correctly wired, allowing for reliable data transmission. Following the color code is essential to avoid wiring mistakes leading to connection failures or poor performance.

Where You'll Find RJ-45 Connectors

From homes to industrial environments, RJ-45 connectors are essential in maintaining stable communication between devices. Let's explore some of their most common uses.

1. Ethernet Networking

Whether you're setting up a local area network (LAN) in an office, school, or home, the RJ-45 connector is the standard for connecting computers, routers, switches, and other network-enabled devices. By attaching this connector to Ethernet cables, users can create wired connections that offer higher stability and speed than wireless options.

2. Data Centers

Data centers rely heavily on wired connections to maintain high-speed data transmission across servers and storage systems. RJ-45 connectors are widely used to ensure consistent and reliable communication between various pieces of networking hardware. 

3. Telecommunications

In addition to Ethernet networking, RJ-45 connectors are also used in telecommunications. The connectors facilitate communication between various devices, such as telephones, modems, and fax machines. 

4. Industrial Applications

In manufacturing, energy, automation, and other industrial settings, shielded RJ-45 connectors protect against electromagnetic interference (EMI). This ensures that the data transmission remains stable and uninterrupted even in environments with heavy machinery and electrical noise. 

5. Home Networking

RJ-45 connectors are just as important in home networking. From connecting computers to routers for fast internet access to linking smart home devices, they ensure devices have a stable and secure connection. Many households use these connectors for wired Ethernet connections to avoid the potential unreliability of Wi-Fi, especially for streaming, gaming, or working from home.

Compare & Find the Best RJ-45 Connector for Your Project

Whether you're wiring a home network, outfitting a data center, or managing industrial communication, selecting the right type of RJ-45 connector can make all the difference in performance and reliability. Octopart makes your search a snap with their platform that lets you explore a vast inventory of connectors, cables and wires, and other components from trusted manufacturers. Easily compare options, check real-time availability, and find the perfect electronic components for your project today!

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FAQs About RJ-45 Connectors

Below, we've addressed some additional questions concerning RJ-45 connectors. Explore additional FAQs, then compare connectors at Octopart.com to determine which will best suit your needs.

Can an RJ-45 connector be used for PoE (Power over Ethernet)?

Yes, an RJ-45 connector can be used for PoE applications. Power over Ethernet enables data and electrical power to transmit over a single Ethernet cable, which eliminates the need for separate power sources for network devices like IP cameras, VoIP phones, and wireless access points. Many modern RJ-45 connectors, especially those used in Cat6 or higher cabling, are PoE-compatible.

What is the maximum cable length for RJ-45 connectors?

The maximum recommended cable length for RJ-45 connectors in Ethernet networking is 100 meters (about 328 feet). Beyond this length, signal degradation and latency can become issues, potentially leading to unreliable communication. For longer distances, fiber optic cables or signal repeaters may be necessary.

What is the difference between a shielded and unshielded RJ-45 connector?

A shielded RJ-45 connector features additional shielding to protect against electromagnetic interference (EMI) and radio frequency interference (RFI). This makes shielded connectors ideal for use in places with high levels of electrical noise, such as factories or industrial settings. Unshielded connectors are more commonly used in low-interference environments like homes and offices.

Can I use an RJ-45 connector for non-Ethernet applications?

Although RJ-45 connectors are primarily used for Ethernet networking, they can also be used in non-Ethernet applications such as serial communication, telecommunications, or custom cable configurations. However, depending on the application, these use cases may require different wiring arrangements or adapters.