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What is RJ45

13/11/2025
by Rick Coleman
What is RJ45

G'day! You've seen them everywhere. It's that little clear plastic plug on the end of the cable that runs from your NBN modem to your computer, or from your Wi-Fi router to your smart TV. It's the plug that makes that satisfying click when you push it in.

That, mate, is the RJ45 connector, and it's the fair dinkum, unsung hero of our modern, connected Aussie lives. But what is RJ45, why is it the standard, and when should you absolutely not mess with it?

So, What is RJ45, Exactly?

RJ45 (which stands for Registered Jack 45) is the technical name for the standard connector used in computer networking. We're talking Ethernet cables, mate.

Its one and only job is to be the plug on the end of a data cable, allowing you to plug your devices into the network. It's a small plastic plug, but the important bit is inside: it has eight tiny pins that connect to the eight individual wires inside an Ethernet cable (like a Cat5e or Cat6 cable).

This 8-pin setup is what allows it to handle the massive, high-speed data streams we need for fast NBN, 4K streaming, and online gaming.

The Big Confusion: RJ45 vs. That Old Phone Plug (RJ11)

This is the bit that catches people out. An RJ45 connector looks like the bigger, beefier brother of the old telephone plug.

  • RJ45 (The Internet Plug): This is the wide one, with 8 pins. It's for data and networking.
  • RJ11 (The Old Phone Plug): This is the skinny little fella, with usually 4 or 6 pins. It's only for old-school landline telephones.

They look similar, but they're not interchangeable, mate. Trying to jam your NBN plug into an old phone socket is a recipe for a bad time.

Why is it the Go-To Connector? (The Ripper Benefits)

The RJ45 is the king of networking for a few simple reasons:

  1. It's Standardised: Every NBN box, modem, router, computer, and smart TV in the world has the same port. It just works.
  2. It's Reliable: That little plastic 'clicky' tab (the one that always snaps off when you stand on it!) is a positive locking mechanism. It holds the plug securely in the socket, so a dodgy connection won't drop you out in the middle of a Zoom call.
  3. It's Fast: The 8-pin design is what allows it to handle the blazing-fast speeds of modern Ethernet, up to 10 Gigabits per second with the right cable.

The CRITICAL Safety & Compliance Warning: DIY vs. Pro

Righto, let's get dead serious for a sec, because this is the most important part of the whole article.

  • DIY: Buying a pre-made Ethernet cable (a 'patch lead') with RJ45 plugs on the end from a shop is a "go for your life" DIY job. Too easy.
  • PRO ONLY: Wanting to install a new data point in your study or home theatre? This involves running a data cable inside your walls and connecting it to a socket (an RJ45 "mech").

In Australia, this is strictly not a DIY job. Any fixed data, communications, or telephone cabling must be installed by a licensed cabler (registered with ACMA).

Why? It's the law, mate. A dodgy data install (especially with cheap parts from a non-specialist supplier) can create interference (messing up your and your neighbour's NBN). Worse, if it's run too close to 240V power wiring without proper separation, it can become a serious electrical hazard. Don't be a galah.

A Professional Job Needs Professional Gear

A licensed cabler or licensed electrician knows that a rock-solid, high-speed network relies on high-quality, compliant components from end to end. They can't risk a job on a cheap, dodgy RJ45 plug that will fail in a year.

This is why they source their gear from a trusted electrical wholesaler. As one of Australia's most comprehensive electrical wholesaler and supplier networks, Schnap Electric Products stocks the lot for the professional installer. They've got a massive range of high-quality, professional-grade data gear, including RJ45 plugs, wall sockets ('mechs'), Cat6 data cable, patch panels, and all the specialist crimping and testing tools that a qualified professional needs to do the job right, compliant, and ready for high-speed Aussie internet. For a connection that won't let you down, the pros start with quality gear from a supplier like Schnap Electric.