2012年4月26日星期四


weeks 10(CABLING)


1. LAN Techonology Cabling :

    a) Cable is the medium through which information usually moves from one network device to another.
    b) Several types of cable are commonly used with LANs.
    c) In some cases,a network will utilize only one type of cable, other networks will use a variety of cable    types.


2. Types of Cables :
   
    Unshielded Twiested Pair (UTP) cable 
    Shielded Twisted Pair (STP) cable
    Coaxial Cable
    Fiber Optic Cable
    Wireless LANs













3. Unshielded Twisted Pair (UTP) cable


UTP Cable Picture

- Four pairs of wires inside the jacket
- each pair is twisted
- help tp eliminate interfereance from adjacent pairs and other electrical devices

4. Category 1 : Voice 9wayar Telefon)
    Category 2 : Data to 4 Mbps (Local Talk)
    Category 3 : Data to 10 Mbps (Ethernet)
    Category 4 : Data to 20 Mbps (16 Mbps Token Ring)
    Catogory 5 : Data to 100 mbps (Fast Ethernet)



5. The standard connector for unshielded twisted pair cabling is an RJ-45 connector



6. Shielded Twisted Pair (STP) cable



- is a type of cable wrapped in a foil shielding
- to help provide a more reliable data communication
- using TOKEN RING topology

7. Coaxial cable




- a single copper conductor at its center
- a plastic layer provides insulation
- the metal shield helps to block interference
- Bayone-Neill-Concelman (BNC) connector
- T-connector, barrer connector, terminator


8. Fibre Optics


- consists of a center glass core surrounded by several layers
- transmit light rather than electronic signals
- eliminate the problem of electrical interference
- transmit signals over much longer distances than coaxial and twisted pair


9. Wireless LANS



10. 10BaseT : Unshielded Twisted Pair : 100 meters
    10Base2 : Thin Coaxial : 185 meters
    10Base5 : Thick Coaxial : 500 meters
    10BaseF : Fiber Optic : 2000 meters

11. Linear Bus : Coax, twisted pair, Fiber : Ethernet, Local talk
      Star : Twisted pair, fiber : Ethernet, Local talk
      Star-wired Ring : Twisted pair : Token ring
      Tree : Coax, twisted pair, fiber ; ethernet