What Are RJ45 Connectors? Here’s What You Should Know


Registered Jack (RJ) connectors have been around for many decades. Originally created by the Bell System, they consist of a standardized interface for telecommunication networks. Most telephones, for instance, use either RJ11, RJ14 or RJ25 connectors. But there are other RJ connectors available, including RJ45. What are RJ45 connectors exactly, and what they are used for?

Overview of RJ45 Connectors

RJ45 connectors are cable connectors that are used in telecommunications applications, primarily network-related telecommunications applications. They look like telephone line connectors but bigger.

Each RJ45 connector has eight pins. Therefore, they are designed for use with eight-conductor cables. The cables with which RJ45 connectors are used have a total of eight conductors or wires. Each wire is color-coded so that RJ45 connectors can be easily installed.

Common applications for RJ45 connectors include the following:

  • Connecting computers to modems and routers
  • Connecting printers to models and routers
  • Connecting smart TVs to modems and routers

RJ45 Specifications

Like all other RJ connectors, RJ45 connectors use a standardized interface. They feature several design specifications that allow for a uniform, standardized interface.

RJ45 connectors are classified as 8P8C connectors. This means they use eight conductors and eight positions. RJ45 connectors feature eight hollow passages. When installing them, you’ll need to place the cable’s eight color-coded conductors inside of these passages. The correct sequence for the conductors is green/white, green, orange/white, blue, blue/white, orange, brown/white and then brown.

RJ45 connectors require crimping. They are crimp-style connectors that are installed with a crimping tool. You’ll need to first strip the ends of the cable’s conductors, after which you can place the exposed conductors inside of the RJ45 connector’s hollow passages (while using the correct sequence). Lastly, you’ll need to crimp the RJ45 connector.

Crimping is the process of permanently joining a connector with a cable. It requires a special tool, known as a crimping tool. You can place the RJ45 connector inside the crimping tool. Upon squeezing the handle, the crimping tool will partially deform the RJ45 connector so that it creates a strong and secure connection with the cable’s conductors.

Another design specification of RJ45 connectors is a retaining latch. Retaining latches are designed to prevent connectors from being accidentally pulled out from the ports in which they are placed. After crimping an RJ45 connector, you can then place the connector inside of a port, such as a computer or modem port. The retaining latch will hold the RJ45 connector in place. To remove it from the port, you’ll need to manually press down on the retaining latch while pulling it.

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