Syllabus
The concept of transmission rates 11 ATAR, 12 GEN
Background
- For a network to work correctly it needs to have connectivity.
- But. How fast is this connectivity?
- That depends on the type of connectors and transmission medium.
- Transmission of data is the speed of the data moving from one place to another.
How is it measured?
- it is measured by how many units pass through the network in a given time
- commonly this is bits per second or bps
- some people call it upload or download speed, or bandwidth
- you may have heard it called megabits per second
Transmission unit
- bits per second = bps
- kilobits per second = kbps = 1000 bits per second or 1024 bits per second
- megabits per second = mbps = 1000 kb per second or 1024 kb per second
Transmission rate influencing factors
- wireless - range; if close, it will transmit faster, concrete walls, metal plates or chicken wire in walls; goes very slow or stops, interference from microwave ovens, other electrical devices
- old copper phone lines - straight wires in plastic sheath, interference from other wires
- twisted pair - twisted wires in plastic sheath, less interference from other wires because of the many twists
- optic fibre - light transmitting pulses; not influenced by interference
- other clients online cable speed greatly reduced by more clients online, wireless speed greatly reduced by more clients online
Transmission rates
- dial up = 56 Kbps
- ADSL = 512 Kbps- 2Mbps
- cable = 512 Kbps- 2Mbps
- Satellite = 512 Kbps
- Optic Fiber = 100 Mbps (but only with no copper wires in the system anywhere)
Tools to measure transmission speed
- the download rate and time are visible at the bottom of the screen when downloading off the internet
- many web services can measure your upload and download speed eg whatismyip speedtest.net
For You To Do
- Choose one of the topics from above.
- Explain it to a friend in the class. The friend and you discuss it further.
- As a pair, you tell the class.
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