What You Need to Know About Ethernet Cables

Ethernet cables are used to connect PC's and other electronic devices to networks, the Internet and to each other.  Currently, there are two primary specifications for Ethernet Cables, Category 5e (Cat 5e) or Category 6 (Cat 6).

Cat 5e and Cat 6 cables are interchangeable (they will both work in the same applications) but Cat 6 are the newer, faster performance cables. Cat 5e cables are rated at 350MHz and Cat 6 cables are rated at 550 MHz.  Cat 5e cables will work fine for most applications, but if you plan to regularly download large files, stream video or music on your PC, or play online games, a Cat 6 network will give you better performance.  Please also note that you will not see any benefit from buying a Cat 6 cable if you continue to use Cat 5e cables in the network, as well, because the Cat 5e cables will bottleneck the data flow and slow down the performance of the Cat 6 cables.  So, if you want Cat 6 performance, all of your cables need to be Cat 6 rated.  All Cat 5e and Cat 6 Ethernet cables are rated for up to 328 feet (100 meters) without signal loss.
 

Both Cat 5e and Cat 6 cables can be manufactured as either Ethernet Patch or Ethernet Crossover cable types.  Ethernet Patch cables (also known as 'straight through' cables) are used to connect a device (e.g., a PC or a video game) to a network (e.g., hub, router or cable/DSL modem.)  Ethernet Crossover cables are used to connect two devices directly to each other (e.g. PC to PC, Video Game to PC, etc.)  There is one exception to these guidelines:  some older DSL modems occasionally require that a device connect to it via an Ethernet Crossover cable, so it is always best to check your users manual or set up instructions to be sure what cable you will require.  Please also note that all Ethernet Patch or Crossover cables come with standard RJ45 gold-plated, male jacks on each end so that they are ready to be plugged into any standard Ethernet socket.

A Cat 6 Ethernet cable should have the following information printed along the length of the cable PVC jacket:  'Category 6 TIA/EIA- 568-B 24 AWG'.  The actual order that these specifications are printed on the cable are unimportant;  just be sure all of this information is on the cable.  The Cat 5e cable will have the same basic information except that it will either say 'Category 5e' or 'Category5 Enhanced'.  It is important to confirm that this information is printed on the cable because, unfortunately, it is still possible to purchase Category 5 (not 5e) cable from some discount cable vendors and it would be a mistake to use this obsolete cable in a modern Ethernet network.   

Despite the preceding paragraph, you may occasionally see a Cat 6 or Cat 5e cable saying that it supports EIA/TIA 568 A.  The EIA/TIA 568 A and B standards are actually both identically straight-through pinned.  That is, they are pin to pin, 1 through 8. The difference is in the color code of the wires inside the jacket. The standards were originally set to improve network performance and consistency between manufacturers. For that reason, if you mix A and B standard cables in a network, the network will run perfectly fine, but if someone has to cut a cable and re-punch it, they may punch it to the wrong standard. Best practice is for all cables that are permanently installed (behind walls, through the floor or ceiling, etc) to be wired to the same standard.

Occasionally, you will see the acronym UTP associated with Ethernet cables.  UTP stands for Unshielded Twisted Pair.  "Unshielded" means that the jacket is standard PVC (see my description of this in a preceding paragrph.  If the cable jacket was shielded, the acronym would be STP (Shielded Twisted Pair.)  "Twisted Pair" refers to the fact that Cat 5e and Cat 6 Eternet cables are actually made up for eight wires which are grouped into four pairs with each pair twisted around each other through the length of the cable.  This special configuration allows a lot more data to be pushed through the cable at a faster rate than if the wires were not twisted around each other.

The 'jacket' or insulation that forms the outside of the cable and holds the eight wires together is generally categorized by three main types:  PVC, Plenum, and Shielded.  A PVC jacket is the typical (and least expensive) insulation that a cable is made with.  It is used in indoor office and/or home settings to connect equipment to wall sockets or other devices.  Plenum jackets are used in situations where the cable can become a fire hazard (PVC jackets release very toxic fumes if burned) and is often required when stringing cables through walls, in celings, and other areas where local fire codes come into play.  Shielded jacket cables are used in those very rare situations in which interference may be caused by nearby equipment that generate high electromagnetic fields that could cause data transmission errors in the cable.  However, the actual instances in which shielded cables are needed are extremely rare.  If you are planning to use an Ethernet cable in an outdoor setting, you are best off by using conduit to protect the cable from the sun and other weathering.  If you use conduit, you can simply purchase standard PVC cables.  There are outdoor grade cables available, but they end up being more expensive than using standard cables and cable conduit, so it is generally not worth the cost for them.

 You may also wish to consider the color of jackets on the Ethernet cables that you purchase.  For example, if you have many cables in your network, you may want to have black 7-foot cables and white 10-foot cables in your inventory so that you can quickly locate the length that you need.  You can also use color to differentiate between Patch (straight-through) and Crossover cables.  Some government organizations (and their contractors) use color-coding to denote the type of information that will be on the network (e.g., green cables for unclassified data, yellow for confidential data, red for top secret data, etc.)  Since there are many colors that Ethernet cables are manufactured in, this type of categorization is quite easy.

There have been specifications developed for some next generation Ethernet cables, including Cat 6e (enhanced Cat 6) and even Cat 7 cables, but as networks stand today, there is little need for these more powerful cables and very few, if any, manufacturers even produce them at this point.

A great online store for finding Ethernet cables (also known as Network Cables) can be found at www.netcablesplus.com