What is “twisted pair” cable and why is it important?

Twisted pair cable is everywhere. Chances are you have quite a bit of it in your home, and even more in your workplace. Twisted pair cable is used for every network wire in your home or office. It’s easy to understand why twisted pair cable is when you look at it — it’s one cable made up of individual smaller cables, and each pair of cables (usually one with a solid color jacket and one with a matching color jacket mixed with white) is twisted together. If there’s no braid around the cable, it’s called “unshielded twisted pair” and you may have heard that term (UTP) used to refer to network cables in the past.

Why twisted pair cable is so common

This is a typical office telephone cable of the type that was used until the end of the 20th century. If you look closely where the connector meets the cable, you’ll see lots of little wires within it. There was a time that every office telephone needed 20 or more wires just to work, and that meant a lot of time and effort wiring everything.

Why the cables get twisted

But why is it there? It seems like twisting the wires is a waste of time. Sure, it makes it easier to see what cable goes with what but the colored outer jackets will do that for you. It turns out, there’s a good reason for twisted pair cable to exist.

Early in the days of telephone wiring, engineers noticed interference from one line to the other on a pole. Simpy swapping the wires as they crossed the pole actually helped with the interference quite a bit. As the cables cross, the noise they generate individually cancels out. There’s quite a bit more engineering theory there, but the point is that simply by crossing two phone lines as they cross the top of a telephone pole makes them work better.

How this affects us today

As more and more businesses demanded fancy phone systems in the 1970s, better methods were created to wire them. The first was category 3 cable with the RJ11 plug. You know this as “regular old phone cable,” the kind used for land line. This cable uses two pairs of the same kind of wiring used for that old monster plug. This made wiring business phone systems a lot easier and cheaper. However, it was limiting.

At the same time, computer networking was just starting. Early systems used big fat multi-wire systems like old phone cables. Later, they moved to coaxial cable which was easier and allowed higher speeds, but was very expensive.

The best solution for both modern phone systems and computer systems is the RJ45 plug with four twisted pairs. You know this as a category 5 or category 6 cable, or perhaps just “an Ethernet cable.” Using the exact same kind of wiring for phones and computers saved a ton of time. Older buildings had a lot of twisted pair capacity sitting unused, and newer ones could get cabled without a lot of cost or effort.

What comes next after twisted pair?

Chances are, we won’t see a lot of changes to wired networking in the future. Today’s network cables using twisted pair wiring are capable of speeds roughly 1,000 times faster than your average office network. That ought to be enough for a while. Beyond that, you can already wire with fiber optics. With fiber, you can have speeds 1,000 times faster than even the fastest twisted pair, in a single strand of fiber the width of a human hair.

I’ll tell you what could happen though. You could have a need for twisted pair cables or fiber. You could need to upgrade your business phone system or your network infrastructure. And, you could need to get excellent service while you’re getting these things. For the best selection. shop at Solid Signal. You’ll find thousands of items that you can’t find anywhere else. If you’re ready to step up to real customer service, call us! We’re here for you during East Coast business hours and we have real trained technicians who can help with your existing problems or recommend new solutions.

Call us at 888-233-7563 or fill out the form below. We’ll get right back to you!

About the Author

Stuart Sweet
Stuart Sweet is the editor-in-chief of The Solid Signal Blog and a "master plumber" at Signal Group, LLC. He is the author of over 10,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.