To transmit data, computers can be connected through twisted pair wires, coaxial cable, optical fibers, and electromagnetic waves.
The simplest way to connect computers is through copper wires. Two wires must be used to make a complete electrical circuit. When you see a pair of wires in a lamp cord, they run in parallel. Originally, network wires were made the same way, but not anymore. Twisted pair refers to two copper wires that are braided together instead of running in parallel.
The wires are braided to enhance reliability. As we noted before, electromagnetic interference is the bane of accurate transmission. However, it turns out that if the wires or a circuit are exposed to the same interference at the same level, the interference tends to cancel itself out. With parallel wires running past some source of interference, one wire is closer to the source than the other and gets a higher level of interference. But when the wires are braided, each wire tends to get the same overall level of interference, reducing the negative effects.
A twisted pair is sometimes covered with a metal mesh, at which point it is called shielded twisted pair, or STP. This shield tends to reduce interference even more. If it doesn't have this additional protection, it is known as unshielded twisted pair, or UTP. The main advantage of twisted pair is its simplicity. It is easy for network technicians to work with because it is very flexible, can fit in tight spaces, and can easily be cut to different lengths. The technology is also very inexpensive.
Coaxial cable refers to a construction in which one wire is placed inside the other. This is the same cable used in cable television. At the end of one of these cables, you'll see a thick wire in the center, and around that, a kind of nut that screws onto a connector on the television or cable box.
If you cut the cable in the middle somewhere, you would see that the thick wire runs through the middle with some insulation, a ring of metal, and a plastic coating around it. The ring of metal connects to that nut on the end. A coaxial cable makes a complete circuit because the wire in the middle is one wire and the ring around the outside acts as the second wire.
Different grades of coaxial cable are available for different applications. They all have the same basic construction, but the width of the layers varies, or different materials might be used for one of the layers. Coaxial cable has a greater bandwidth than twisted pair. In general, the thicker the wire, the more data it can transmit at once, and cable uses thicker wire than twisted pair.
Coaxial cable has some disadvantages, though, that can offset the higher bandwidth. The cable is so thick that it cannot easily fit around tight corners, it is more expensive, and, compared to twisted pair, it is more difficult to cut and make connectors.
One problem that twisted pair and coaxial cable share is that signals in copper wires tend to fade over a distance. This explains why two televisions in a house on the same cable system can have varying reception: one television has a longer cable than the other. To combat this, network designers install repeaters, which are devices that read a signal on one wire and reproduce it on another. In this way, longer distances can be covered.
Our website is not responsible for the information contained by this article. Articleinput.com is a free articles resource thus practically any visitor can submit an article. However if you notice any copyrighted material, please contact us and we will remove the article(s) in discussion right away.
Note: This article was sent to us by: Raymond Harris at 02132011
1. Interactive shape deformation
All articles are property of their respective authors. Please read our Privacy Policy!
© 2009 ArticleInput.com.
Partners: Damenmode