If you’ve ever browsed cables online, you’ve probably noticed that they’re nearly always classified as “Cat-5,” “Cat6e,” or something similar thereof. “Cat” simply stands for “Category,” and the following number indicates the specifications to which the cable was manufactured. A general rule of thumb is that higher numbers represent faster speeds and higher frequencies, measured in Mhz. As is the case with most technologies, newer cables tend to support higher bandwidths, and therefore increased download speeds and faster connections.

Keep in mind that longer Ethernet cables will result in slower transmission speeds, though cables bought for personal use rarely exceed 100 meters, where speed dropoff typically begins to occur.

In September, the Institute of Electrical and Electronic Engineers (IEEE) unveiled a new Ethernet standard that promises to dramatically improve transmission speeds on Cat 5 and Cat 6 cables. Unfortunately, it might be a few years before the standard is available to the general public, as opposed to enterprise customers. Below, you can see what each cable type is capable of.

Cat 3 and Cat 5

Both Cat 3 and Cat 5 Ethernet cables are, at this point, obsolete. It’s not unheard of to find Cat 5 cables still in use, but you shouldn’t even think about trying to buy either of these Ethernet cables. They’re slow, and nobody makes them anymore.

Cat 5e

The “e” in Cat 5e stands for “Enhanced.” There are no physical differences between Cat 5 and Cat 5e cables, but 5e Ethernet is built under more stringent testing standards to eliminate crosstalk — i.e. the unwanted transfer of signals between communication channels. Cat 5e is currently the most common type of Ethernet, namely due to its low production cost and its ability to support faster speeds than the original Cat 5 cables.

Cat 6

Cat 6 cables support much higher bandwidths than Cat 5 and Cat 5e cables, though they’re also more expensive. Cat 6 cables are more tightly wound than those of their predecessor, and are often outfitted with foil or braided shielding. This shielding protects the twisted pairs of wires inside the Ethernet cable, helping to prevent crosstalk and noise interference. Cat-6 cables can technically support speeds up to 10 Gbps, but can only do so for up to 55 meters.

Cat 6a

The “a” in Cat 6a stands for “Augmented.” In comparison to the regular Cat 6 cables, 6a cables support twice the maximum bandwidth, and are capable of maintaining higher transmission speeds over longer cable lengths. Cat 6a cables are always shielded, and their sheathing — which is thick enough to eliminate crosstalk completely — makes for a much denser, less flexible cable than Cat 6.

Cat 7

Cat 7 cables utilize the newest widely-available Ethernet technology, and support higher bandwidths and significantly faster transmission speeds than Cat 6 cables. They’re proportionally more expensive than other Ethernet cables, though their performance reflects their premium price tag. Cat 7 cables are capable of reaching up to 100 Gbps at a range of 15 meters, making them an excellent choice for connecting modems or routers directly to your devices. Cat 7 cables are always shielded, too, and use a modified GigaGate45 connector, which is backwards compatible with regular Ethernet ports.

Cat 8

Cat 8 cables are still in development. We can expect them to hit the market relatively soon, however, with faster maximum speeds and higher maximum bandwidths than Cat 7 cables.

How do you choose?

The easiest way to select a cable is to pick the one with the range and performance you need. But what do you need?

Start with the speed of your home Internet connection. If you have Gigabit Internet, an old Ethernet cable will hold you back. But if you have a slow connection, say 10 or 20 megabits per second, you’re good with anything Cat 5 or newer.

Next, consider the speed you need for your network. This is frankly irrelevant for most home users. But if you move big files between computers frequently, or you stream extremely high-bandwidth video content, a better Ethernet cable can make a difference.

Finally, consider your router. So cheap routers only support Ethernet up to 100 megabits per second, so it’s going to bottleneck anything newer than Cat 5. Even the best home routers rarely support better than Gigabit Ethernet, so Cat 6a and Cat 7 are of questionable use.

With all of the above consider, a Cat 6 cable is the most you’ll likely need, and most homes can get away with Cat 5e.

Ethernet glossary

The differences between the various types of Ethernet cables are actually pretty simple, but it’s easy to get confused by some of the nomenclature. To help out, we’ve put together a quick rundown on what different terms mean, and what you should expect if you buy a cable with those designations.

Cat: Stands for “Category.” See previous page.

TP: Twisted Pairs. This terminology refers to the way that the wires inside the cable are twisted together. Twisted Pair has been an industry standard for years, and is only inferior to fiber optic cabling in terms of maximum length and speed dropoff.

UTP: Unshielded Twisted Pairs. Cables designated UTP won’t have foil or braided shielding, which makes the cable cheaper to produce and more flexible, but you’ll sacrifice signal quality and increase vulnerability for crosstalk.

STP: Shielded Twisted Pairs. Cables with STP or SSTP designations are protected with braided shielding, which is usually made of copper or another conductive polymer. Shielding reduces noise and, therefore, improves connection quality.

FTP: Foiled Twisted Pairs. Cables with FTP or SFTP designations are protected with foil shielding, which help reduce noise and improves connection quality.