WEEK 7 : CABLES

CABLES

·      LAN Technology  Cabling.

·      A wireless LAN or WLAN is a wireless local area network, which is the linking of two or more computers without using wires.

·      LAN utilizes spread-spectrum based on radio waves to enable communication between devices in a limited area, also known as the basic service set.

Types Of Cables

Ø  Unshielded Twiested Pair (UTP) cable

Ø  Shielded Twisted Pair (STP) cable

Ø  Coaxial Cable

Ø   Fiber Optic Cable

Ø  Wireless LANs

UNSHIELDED TWISTED PAIR (UTP) CABLE

§  4 pairs of wires inside the jacket

each pair is twisted with a different number of twisted per inch

5 categories:

category 1 : voice ( telephone wire)

category 2 : data to 4Mbps (local talk)

category 3 : data to 10Mbps (ethernet)

category 4 : data to 20Mbps (16Mbps token ring)

category 5 : data to 100Mbps (fast ethernet)

standard connector is an RJ-45 connector

Disadvantage of UTP : may be susceptible to radio and electrical frequency interference.

SHEILDED TWISTED PAIR (STP) CABLE

Consist of tw0 individual wires wrapper in a foil shielding-help provide a more realiable data communication suitable for environments with electrical interference. Extra shielding can make the cables quite bulky.

COAXIAL CABLE

Ø  has a single copper conductor at its center

Ø  a plastic layer provides insulation between the center conductor and a braided metal shield

Ø  the metal shield helps to block any outside interference from fluorescent lights,motors, and other computers.

coaxial cable connector:

Bayone-Neill-Concelman (BNC) connector

different types of adapters are available for BNC connectors, including:

v T-connector

v barrel connector

v terminator

FIBRE OPTIC CABLES

v consists of a center glass core surrounded

v transmits lightrather than electronic signals eliminating the problem of electrical interference.

v large amount of electrical interference

v able to transmit signals over much longer distances than coaxial and twisted pair.

WIRELESS LANS

Wireless telecommunications is the transfer of information between two or more points that are not physically connected.