Transmission Media (Cambridge (CIE) A Level Computer Science) : Revision Note

Wired vs wireless

What is a wired network?

• A wired network is a network where physical cables are used to join devices together and transmit data

• Computers can be connected to networks using many different types of wires to transmit data

• The most common types of cables in a wired network are:

  • Ethernet

  • Fibre optic

  • Copper

Advantages & disadvantages of wired networks

What is a wireless network?

• A wireless network is a network where connections are made using radio waves to transmit data through the air

• The most common types of wireless connections are:

  • Wi-Fi

  • Bluetooth

What is Wi-Fi?

• Wireless fidelity (Wi-Fi) is a common standard for wireless networks

• Wi-Fi is common in most homes and offices to connect devices such as laptops, tablets & smart phones

• Using Wi-Fi, devices communicate with a wireless access point (WAP), which can be a standalone device or built into a router or switch 

What is Bluetooth?

• Bluetooth is another common standard for wireless networks

• Bluetooth is common in most homes and offices to connect devices such as headphones, controllers, keyboards & mice

• Bluetooth is used typically for a direct connection between two devices 

Advantages and disadvantages of wireless networks

Types of media

What is transmission media?

• Transmission media is the type of cable used in wired connections

• Wired connections offer a higher bandwidth than wireless connections 

• The main options for transmission media are:

  • Twisted pair

  • Coaxial

  • Fibre-optic

Twisted pair

• Carries electrical signals between devices on a local area network (LAN)

• Common in offices and homes to connect devices such a desktop computers & servers

• Allow duplex communication

• Slower transfer rate compared to coaxial and fibre-optic

• Can suffer from external interference (electromagnetic radiation)

• Low cost

Coaxial

• Used in telecommunication to transmit voice signals, forming the traditional landline phone network

• Adapted to deliver network traffic on a wide area network (WAN) making the internet possible

• Degrades over time which limits their range compared to fibre optic

• Suffers from interference which can disrupt data quality

• Transmits data at a much slower rate, and has a much lower bandwidth compared to fibre optic

Fibre optic

• Uses light to transmit data on a wide area network (WAN)

• Transmits data at high speed and has a higher bandwidth compared to copper cables

• Does not suffer from interference which makes them the most secure option to send sensitive data

• Can cover a long distance without any degradation, they can span cities and countries

Quick comparison