Tuesday, December 30, 2014

What are the Technical and Physical Differences between Ethernet Cables?

Which Ethernet cable do you should use? How do you know? In fact, Ethernet cables look the same, but they are different. So in the following short guide we take a look at the technical and physical differences between the Ethernet cables.























Ethernet cables are grouped into sequentially numbered categories (e.g. CAT5) based on different specifications; sometimes the category is updated with further clarification or testing standards (e.g. CAT5e, CAT6a). These categories are how we can easily know what type of cable we need for a specific application.


CAT Technical Differences
The difference in Ethernet cable specification is not as easy to see as physical changes; so let’s look at what each category does and does not support. Below is a chart for reference when picking cable for your application based on the standards for that category.

When you pick Ethernet cable, you can refer to the following table to check the standard of each category.

Length
10Mb/s
100Mb/s
1GbE
10GbE
PoE
Mhz
CAT5
100


100
CAT5e
100

100
CAT6
100 (55 for 10GbE)
250
CAT6a
100
500

You may notice that as the category number gets higher, so does the speed and Mhz of the wire. This is not a coincidence, because each category brings more stringent testing for eliminating crosstalk (XT) and adding isolation between the wires.

Category 5 cable was revised in 2001, and mostly replaced with Category 5 Enhanced (CAT5e) cable which did not change anything physically in the cable, but instead applied more stringent testing standards for crosstalk. Category 6 was revised between 2002 with Category 6 Augmented (CAT6a) in 2008 that provided testing for 500 Mhz communication (compared to CAT6 250 Mhz). The higher communication frequency eliminated alien crosstalk (AXT) which allows for longer range at 10 Gb/s.


Physical Differences Between These Ethernet Cables
How does a physical cable eliminate interference and allow for faster speeds? It does it through wire twisting and isolation. 

Cable twisting reduced the interference and increased the range. Twisted pair became the basis for all Ethernet cables to eliminate interference between internal wires (XT), and external wires (AXT).

There are two main physical differences between CAT5 and CAT6 cables, the number of twists per cm in the wire, and sheath thickness.

Cable twisting length is not standardized but typically there are 1.5-2 twists per cm in CAT5 (e) and 2+ twists per cm in CAT6. Within a single cable, each colored pair will also have different twist lengths based on prime numbers so that no two twists ever align. The amount of twists per pair is usually unique for each cable manufacturer.

Many CAT6 cables also include a nylon spline which helps eliminate crosstalk. Although the spline is not required in CAT5 cable, some manufacturers include it anyway. In CAT6 cable, the spline is not required either as long as the cable tests according to the standard.

The nylon spline helps reduce crosstalk in the wire, with the thicker sheath protecting against Near End Crosstalk (NEXT) and Alien Crosstalk (AXT), which both occur more often as the frequency (Mhz) increases. In this picture below, the CAT5e sheath has the thinnest sheath versus CAT6 but it also was the only one with the nylon spline.


Shielded (FTP) vs. Unshielded (UTP)
Because all Ethernet cables are twisted, manufacturers use shielding to further protect the cable from interference. For example, Unshielded Twisted Pair (UTP) can easily be used for cables between your computer and the wall but you will want to use Foil Shielded Cable (FTP) for areas with high interference and running cables outdoors or inside walls.

There are different ways to shield an Ethernet cable, but typically it involves putting a shield around each pair of wire in the cable. This protects the pairs from crosstalk internally. Manufacturers can further protect cables from alien crosstalk with additional cable shielding beneath the sheath. The diagram below shows the different types of Ethernet shielding and the codes used to differentiate them.
























The code before the slash designates the shielding for the cable itself, while the code after the slash determines the shielding for the individual pairs: TP = twisted pair, U = unshielded,F = foil shielding, S = braided shielding

Solid vs. Stranded
Solid and stranded Ethernet cables refer to the actual copper conductor in the pairs. Solid cable uses a single piece of copper for the electrical conductor while stranded uses a series of copper cables twisted together. There are many different applications for each type of conductor, but there are two main applications for each type you should know about.



















Key Differences: Stranded cable vs. Solid cable
  • Stranded cable is more flexible and should be used at your desk or anywhere you may be moving the cable around often.
  • Solid cable is not as flexible but it is also more durable which makes it ideal for permanent installations as well as outdoor and in walls.
Now you may be clear that which type of cable you should use. If you want to order Ethernet cables for connecting your routers, you can visit the leading Cisco supplier-router-switch.com for more details, or email their sales representatives.


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3 comments:

  1. Excellent article on Ethernet Cables which are explained in detail. thanks for sharing interesting and useful information. Everything is very interesting to learn and easy to understood.

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  2. This information is well but if you using cables you must buy from smartect cables specialy its cat6 plenum because i am also use this and i am very satisfied and they also provide 1000ft cables this is a new brand and it gives cheap price with good quality

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