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Types of transmission media including;              11 ATAR, 12 GEN

  • optic fibre
  • wired
  • wireless 


  • A computer can be used to send or receive information.
  • It is the network that does this.
  • no network = no internet
  • Movement of data by upload or download is called transmission of data.
  • For this data to move, it needs to go through the air or through cables.

Optic fibre

  • optical fibre cabling has very long strands of glass inside a cable
  • data travels inside the strands of glass as pulses of light
  • the size of the strand of glass = the size of a human hair
  • data = light
  • each optic fibre cable can carry 1 or more strands of glass
  • centre part of the optic fibre cable is the strands of glass
  • outside of this is a cladding to reflect the light back into the cable
  • outside of this is buffer coating to protect the cable
  • disadvantages; expensive, difficult to join
  • advantages; fast, no interference

Wired twisted pair - ethernet cable

  • very commonly used in networks today
  • contains 4 pairs of wires
  • is set on the 802.3 standard
  • twisted every cm in a tight twist to minimize electrical interference
  • sometimes shielded completely in aluminium foil to prevent electrical interference
  • has an rj-45 male connector on each end
  • plugs into an rj-45 female connector wall
  • data speed on a category 5 (cat5) cable less than 90 metres is capable of 100 Mbps 
  • data speed on a category 6 (cat6) cable less than 90 metres is capable of 1000 Mbps
  • for 100 Mbps 2 wires are commonly used.
  • for 1000 Mbps all 4 pairs of wires are commonly used

Wired - coaxial cable

  • not commonly used in networks today
  • used in bus networks
  • consists of 2 wires
  • a centre wire, surrounded by a plastic insulator
  • an external braided wire, which surrounds the plastic insulator
  • finally a protective covering around the cable
  • data speed on a coaxial cable less than 180 metres is 10 Mbps

Wireless - radio waves

  • used for mobile clients
  • it uses radio waves
  • must have a transmitter and a receiver to send / receive data
  • the devices must have a wireless adapter to transmit and receive
  • must be configured prior to working, usually a network name, username and password
  • the receiving antenna in a school location is a wireless access point (WAP)
  • hot spots are common 'free' wireless locations that are configured to have no username and password
  • the working range indoors is up to 20 metres depending on wall construction and type of wireless setup
  • the working range outdoors is up to 100 metres, depending on the type of wireless setup
  • wireless setup is based on a standard called 802.11
  • it has additions onto the number 11 for newer and improved versions eg 802.11a, 802.11b, 802.11g, 802.11n
  • wireless operates around 2.4 Ghz range, or around the 5 Ghz range

Wireless - bluetooth

  • used for short distances up to 10 metres
  • uses short range radio waves at the 2.45 Ghz frequency
  • is a small microchip that can transmit and receive data
  • it is very common in mobile devices
  • the bluetooth controller is the Link Manager (LM)
  • the Link Manager identifies other bluetooth devices, creates links, sends and receive data
  • the Link Manager also controls the operation mode, eg standby (wake each 2 secs to listen), master/slave (initiating link=master), inquiry (causes devices to ID), park (wakes at intervals, listens syncs), hold (power saving, but discoverable)

 For You To Do

  1. Locate the wireless access points in your school. Draw a rough map of these wireless access point locations.
  2. Make up some advantages and disadvantages for the wired and wireless systems.
  3. Explain types of wired networking in your own words.
  4. Explain types of wireless networking in your own words.
 Learn more about optical fibre from youtube
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