Types of transmission media including; 11 ATAR, 12 GEN
- optic fibre
- 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.
- 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
- Locate the wireless access points in your school. Draw a rough map of these wireless access point locations.
- Make up some advantages and disadvantages for the wired and wireless systems.
- Explain types of wired networking in your own words.
- Explain types of wireless networking in your own words.
Found an error or enhancement? Please fill out this contact us form.