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Ethernet Cable Identification and Use:

Category 5, Cat. 5e, Cat. 6, Cat. 6a, Cat. 7, and Cat. 7a Cable Comparison

So you've got a bundle of ethernet cables and you're not really sure if you should use them in your network, this short guide should help you identify and correctly use any of the common ethernet cables you are likely to run across.

Identify the Cable

Category 6 Ethernet Cable Category 5 Ethernet Cable Category 5e Ethernet Cable
As you see above almost all ethernet cabling has the category of cabling printed on the side (hover over an image for the caption). The category shows what bandwidth the cable is rated to carry. If you encounter anything other than the categories listed in the table below, you probably should not use them in your network.

Below you can see that the various categories of cable can be relatively reliably identified by the end connector and the diameter of the cable, however, this is not a be all end all. In general a higher category of cable is thicker because it uses thicker wire for better transmission quality. If you are at all unsure, always check the printing on the side of the cable.

Image of Cat. 6, Cat. 5e, Cat. 5, and a standard telephone cable
From top to bottom: Cat. 6, Cat. 5e, Cat. 5, and a standard telephone cable for comparison.

Common Ethernet Categories, Speed, and Usage

Type Speed Detailed Information
Cat. 5 10/100/1000MbE* Category 5 cable is a currently outdated standard that provides support for up to 100Mhz operation. It can be used for 10/100 Ethernet without worry, however for longer runs of 1000MbE it is recomended to use Cat. 5e or higher.
Cat. 5e 10/100/1000MbE Category 5e cable provides support for frequencies up to 100Mhz. Cat. 5e generally provides the best price for performance, however for future proofing Cat. 6 or higher might be a better choice as it usually does not cost much more.
Cat. 6 10/100/1000MbE
Category 6 is defined up to a frequency of 250Mhz. Allowing 10/100/1000 use with up to 100 meter cable length, along with 10GbE over shorter distances.
Cat. 6a 10/100/1000MbE
Cat. 6a or Augmented Category 6 is defined up to 500Mhz. It allows up to 10GbE with a length up to 100m.
Cat. 7 10/100/1000MbE
Category 7 is the informal name for "Class F" cabling defined by a different standards body than Cat. 6a and lower. It supports frequencies up to 600Mhz and may support the upcoming 100GbE standard
Cat. 7a Unknown Category 7a is an upcoming standard that allows frequencies up to 1000Mhz. Supported Ethernet bandwidths have not been defined.


MbE stands for Megabit Ethernet, 100MbE means that the cable can carry 100 Megabits per second of Ethernet trafic.
GbE stands for Gigabit Ethernet, 10GbE is equivalent to 10000MbE.
* Speeds marked with a star are possible over a short run (less than 10 meters) on that category, however for longer runs up to 100m it is reconmended to use a higher quality cable.

General Tips For Using Ethernet Cables

  • Do run cables over distances up to 100 meters with their rated speed.
  • Do mix different cable types as long as the minimum cable category supports the maximum speed of your network. As noted in the table above, all the cables are backward combatible with prior ethernet standards.
  • Do make your own cable if you need lots of varying lengths. More information can be found here.
  • Do buy cables that have no-catch connectors, as seen in the two left-most images of Cat. 6 cable below (hover over the image for the caption). A no-catch connector won't snag on carpets, clothing, and other cables when you are installing it. The right-most image indicates a traditional connector.
    Category 6 Ethernet Cable with no-snag connector Category 6 Ethernet Cable with no-snag connector Category 5e cable with traditional snagging connector
  • Don't order anything less than Cat. 5e cable.
  • Don't use cable in your network if it is rated less than the maximum speed of the network.
  • In most cases don't buy cable from retail stores. BestBuy sells 25' of Cat. 6 cable for $30, you can buy the same from online stores for ~$10 shipped.
  • Don't buy overpriced "super-high-quality" cable. This $500(!) cable comes to mind. If a cable is rated as Cat. 5e then it will perform at that rating.
  • Don't crimp or staple cable, this can easily cause breaks in the cable which are sometimes hard to track down.
  • Ethernet cables are not directional in any way, you cannot install one backwards.
  • Lighter colored cables are usually a better choice for two reasons: They are easier to see in the dark, and it's easier to read the cable catogory stamped on the side.
  • Use a patch cable when connecting a computer to a router or hub, use a cross over cable when connecting two computers directly together. If you are unsure, buy a patch cable, if the cable is not labled as "patch" or "cross over" it is a patch cable.

Kevin Castor July 10th 2008 kcas88@gmail.com
Last Updated May 21st 2011

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