Sunday, July 8, 2012

Network Cable Types

There several different types of cable that are used in computer networking. However for must users, especially home users, the only type of cable used is twisted pair "Cat" cable. There are currently seven different category cables: category's 1-7. Category 1-4 cables are not used in computer networking and instead are usually used for analog applications such as phone. Categories 5-7 are used for networking, with each higher number representing faster speeds.

Twisted pair cabling - probably better known as "Cat" cable

Twisted pair cabling is called twisted pair because the pairs of wire within the cable are twisted around each other. This twisting in of the wires helps prevent crosstalk; crosstalk is simply the picking up of unwanted interference, both from within the cable itself and from cables that may be nearby. Twisted pair cable is probably better known by its specifications currently Category 1-7. Only Categories 5-7 are used in computer networking, with the first 4 generally being used for analog applications such as phone. Category cables 5-7 all have 4 pairs of wire, with 2 wires to a pair, for a total of 8 wires. Category cables 5-6 uses a RJ45 termination jack. A RJ45 jack looks very similar to phone jack, except for the fact that it is slightly larger and has 8 connections rather than 4. The most common cable type, at least for home users, is Category 5e. Category 5e has a max speed of 1000Mbs or 1Gbs with a max length of 100 meters.

Category 1 cable type is not commonly used any more, and is listed as unsuitable for modern communication devices. Category 1 cable supports a frequency bandwidth of 0.4 MHz and was originally used for telephone and modem communications. Category 1 cable was never recognized by the EIA/TIA as a valid cable type.

Category 2 cable is not used anymore and is listed as unsuitable for modern communication devices. Category 2 cable supports a frequency bandwidth of 4 MHz. Originally category 2 cable was used for ARCnet and 4 Mbs Token Ring networks. Category 2 cables was the first cable to support speeds of up to 4 Mbs, which back then was fast! Category 2 cable was never recognized by the EIA/TIA as a valid cable type.

Category 3 cable is currently used primarily for phone and modem communication devices. Category 3 cable supports a frequency of 16 MHz and is cable of speeds up to 100 Mbs. Category 3 cable supports 10BASE-T and 100BASE-T4 (which simply means it uses all 4 pairs), as well as Token Ring and ATM25 networks. Category 3 cable is still recognized by the EIA/TIA as a valid cable type.

Category 4 cable is not commonly used except for phone/data communications, which is not common. Category 4 cable supports a frequency of 20 MHz and is cable of speeds up 100 Mbs over 4 pair. Category 4 cable supports 10BASE-T, 100BASE-T4, and 16 Mbs Token Ring. Category 4 cable is no longer recognized by the EIA/TIA as a valid cable type.

Category 5 is not commonly used anymore; instead Category 5e has superseded Category 5. You may still find Cat 5 cables bundled with cheap electronics as well as in older network installations. Category 5 cable supports a frequency of 100 MHz and speeds up 1000 Mbs. Category 5 cable is most commonly used in 100BASE-TX and 1000BASE-T. Category 5 cable is no longer recognized by the EIA/TIA as a valid cable type.

Category 5e is probably the most common cable type and is found in most new installations. Category 5e (enhanced) has bascially the same specifications as Category 5.

Category 6 cable is starting to replace category 5e, especially in applications where higher speeds are needed. Category 6 cable supports a frequency of 250 MHz and has better resistance to crosstalk. Category 6 cable can support up to 10 Gbs; however, using a Category 6 cable for 10 Gbs will result in a shorter allowable length of only 55 meters. Category 6 cable can support up to 10GBASE-T.

Category 6a has similar specifications as category 6, except it supports a frequency of 500 MHz and allows 10 Gbs to be run for the full 100 meters.

Category 7 is the newest cable type and supports speeds up to 10 Gbs. Category 7 cable supports a frequency of 600 MHz. The main difference between other cable types is the fact that category 7 cable is even more resistant to crosstalk. Category 7 cable has shielding around the cable as well as around each pair of the cable. Category 7 supports 10GBASE-T.

Category 7a cable has similar specifications as category 7, except it supports a frequency of 1000 MHz. Currently the highest speed supported by category 7a is 10 Gbs; it is possible in the future though that it might support 40-100 Gbs.

All the different wires I listed above have one thing in common, 4 pairs of wire. The wires inside the cable are all color coded starting with blue, white blue, green, white green, orange, white orange, brown, and white brown. In my experience cable manufactures vary the color on the cables that have white, sometimes they are all white with a colored stripe or sometimes they are all colored with just a white stripe.

Which cable type should you choose? It basically comes down to what speed do you want? For most home users Category 5e will be sufficient, which allows for speeds up to 1 Gbs. Although, you may want to consider Cat 6 for future applications.

Of course twisted pair cable is not the only type of cable you can use for networking; there is also coaxial and fiber. On top of that you also have Ethernet over power lines as well as Wi-Fi. I will just quickly mention these other types of cables since they either are not used any more or are used in business settings for high-speed backbones.

Coaxial cable comes in two types, thicknet (10BASE5) and thinnet (10BASE2). Thicknet has a max length of 500 meters and thinnet has a max length of 185 meters. Coaxial cable supports a max speed of 10 Mbs.

Fiber cable is for long cable runs (miles) and high speeds without out having to worry about crosstalk. Fiber cable contains a glass inner core that transmits light, because fiber cables use light they are not affected by electrical magnetic interference. There are two types of fiber cable, multi-mode and single-mode. The main difference between multi-mode and single-mode is multi-mode cable has a larger core, which makes it cheaper, but shortens the distance and speed of the cable.

Ethernet over powerlines relies on existing wiring, namely your electrical wires. This eliminates the need for you to run cables and allows you to get to places that might normally be hard or impossible to reach with a regular networking cable. For powerline networking you will need adapters that plugs into your outlet. Powerline networking is slower than using a regular network and is also affected by the length and quality of your electrical wires and connections. A good use for powerline networking are places where Wi-Fi might have trouble reaching, such as through thick walls or multiple floors.

Wi-Fi is wireless networking and has grown exceedingly popular over the last few years as more people are using mobile devices such as laptops, tablets, and smartphones. Wi-Fi with the proper equipment can also be used for long distances. Wireless routers or access points can be setup as a wireless bridge, you can use this setup to bridge a distance without a wire and then on the opposite end have a wired connection available.


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