Thursday, October 1, 2009

NETWORKING CABLE

26/8/2009

NETWORKING CABLE 2...PRO'S N CON'STypes of Networking Cables:The three main types of networking cables are coaxial cable, twisted-pair cable and fiber optic cable and the differences................

Coaxial Cable:

Coaxial cable is made of two conductors that share the same axis; the center is a copper wire that is insulated by a plastic coating and then wrapped with an outer conductor (usually a wire braid). This outer conductor around the insulation serves as electrical shielding for the signal being carried by the inner conductor. A tough insulating plastic tube outside the outer conductor provides physical and electrical protection.
At one time, coaxial cable was the most widely used network cabling. However, with improvements and the lower cost of twisted-pair cables, it has lost its popularity.

Network Cable Types:

There are two types of coaxial cable.
1. ThickNet
2. ThinNet

ThickNet:

ThickNet is about .38 inches in diameter. This makes it a better conductor, and it can carry a signal about 1640 feet (500 meters) before signal strength begins to suffer. The disadvantage of ThickNet over ThinNet is that it is more difficult to work with. The ThickNet version is also known as standard Ethernet cable.

ThinNet:

ThinNet is the easiest to use. It is about .25 inches in diameter, making it flexible and easy to work with (it is similar to the material commonly used for cable TV).ThinNet can carry a signal about 605 feet (185 meters) before signal strength begins to suffer.

Twisted-Pair Cable:

Twisted-pair cable consists of two insulated strands of copper wire twisted around each other to form a pair. One or more twisted pairs are used in a twisted-pair cable. The purpose of twisting the wires is to eliminate electrical interference from other wires and outside sources such as motors. Twisting the wires cancels any electrical noise from the adjacent pair. The more twists per linear foot, the greater the effect.

Network Cable Types

There are two types of twisted pair cable

1. Shielded Twisted Pair (STP)
2. Unshielded Twisted Pair (UTP)

Shielded Twisted Pair (STP):

The only difference between STP and UTP is that STP has a foil or wire braid wrapped around the individual wires of the pairs. The shielding is designed to minimize EMI radiation and susceptibility to crosstalk. The STP cable uses a woven-copper braided jacket, which is a higher-quality, more protective jacket than UTP.

Unshielded Twisted Pair (UTP):As the name implies, "unshielded twisted pair" (UTP) cabling is twisted pair cabling that contains no shielding.

UTP cables can be divided further into following categories:
Category 1 : Traditional telephone cable. Carries voice but not data
Category 2 : Certified UTP for data transmission of up to 4 megabits per second (Mbps). It has four twisted pairs
Category 3 : Certified UTP for data transmission of up to 10 Mbps. It has four twisted pairs Category 4 : Certified UTP for data transmission of up to 16 Mbps. It has four twisted pairs
Category 5 : Certified for data transmission of up to 100 Mbps. It has four twisted pairs of copper wire
Category 6 :Offers transmission speeds up to 155 Mbps
Category 7 :Category 7 is a proposed standard that aims to support transmission at frequencies up to 600 MHzTwisted-pair cable has several advantages over other types of cable (coaxial and fiberoptic): It is readily available, easy to install, and inexpensive. Among its disadvantages are its sensitivity to electromagnetic interference (EMI), its susceptibility to eavesdropping, its lack of support for communication at distances of greater than 100 feet, and its requirement of a hub (multiple network connection point) if it is to be used with more than two computers. Twisted pair cables use RJ45 connector.

Fiberoptic Cable:

Fiberoptic cable is made of light-conducting glass or plastic fibers. It can carry data signals in the form of modulated pulses of light. The plastic-core cables are easier to install but do not carry signals as far as glass-core cables. Multiple fiber cores can be bundled in the center of the protective tubing.

Network Cable Types

When both material and installation costs are taken into account, fiberoptic cable can prove to be no more expensive than twisted-pair or coaxial cable. Fiber has some advantages over copper wire: It is immune to EMI and detection outside the cable and provides a reliable and secure transmission media. It also supports very high bandwidths (the amount of information the cable can carry), so it can handle thousands of times more data than twisted-pair or coaxial cable.Cable lengths can run from .25 to 2.0 kilometers depending on the fiberoptic cable and network. If you need to network multiple buildings, this should be the cable of choice. Fiberoptic cable systems require the use of fiber-compatible NICs.

Twisted pair cabling is a form of wiring in which two conductors (the forward and return conductors of a single circuit) are twisted together for the purposes of canceling out electromagnetic interference (EMI) from external sources; for instance, electromagnetic radiation from Unshielded Twisted Pair (UTP) cables, and crosstalk between neighboring pairs.

Unshielded Twisted Pair (UTP)

This is the most popular form of cables in the network and the cheapest form that you can go with. The UTP has four pairs of wires and all inside plastic sheathing. The biggest reason that we call it Twisted Pair is to protect the wires from interference from themselves. Each wire is only protected with a thin plastic sheath.

Shielded Twisted Pair (STP)

Is more common in high-speed networks. The biggest difference you will see in the UTP and STP is that the STP use’s metallic shield wrapping to protect the wire from interference.-
Something else to note about these cables is that they are defined in numbers also. The bigger the number the better the protection from interference. Most networks should go with no less than a CAT 3 and CAT 5 is most recommended.-Now you know about cables we need to know about connectors. This is pretty important and you will most likely need the RJ-45 connector. This is the cousin of the phone jack connector and looks real similar with the exception that the RJ-45 is bigger. Most commonly your connector are in two flavors and this is BNC (Bayonet Naur Connector) used in thicknets and the RJ-45 used in smaller networks using UTP/STP.

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