What is an RJ45?

RJ45 or Ethernet cable
Cable guy: Ethernet is also known as RJ45

If you’re on the lookout for a new laptop or PC, you might see an RJ45 port listed in the specs, alongside the USB ports and other connections. What is an RJ45? And is it something you need? Let’s find out.

What RJ45 means

RJ45 is the connector used for Ethernet cables. If you plan to have a wired internet connection from your router to your PC or laptop, you will need an RJ45 port, more commonly referred to as an Ethernet port.

Alas, on today’s super-slim laptops, Ethernet ports are becoming increasingly rare. If your computer doesn’t have an RJ45/Ethernet port, you can buy an adapter or hub that slots into one of the USB ports.

What does RJ45 stand for?

RJ45 stands for Registered Jack 45. There are various types of Registered Jack used in the telecoms industry, ensuring that various bits of communications equipment can easily connect to one another.

The actual standard used for Ethernet cable connectors is RJ45S, but it’s commonly referred to without the S on the end.

Can you add more Ethernet ports to a router?

About the author

Barry Collins

Barry has scribbled about tech for almost 20 years for The Sunday Times, PC Pro, WebUser, Which? and many others. He was once Deputy Editor of Mail Online and remains in therapy to this day. Email Barry at

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