Hardware and network technologies - CCEACommunications technologies

Wi-fi is a trademarked name for the IEEE 802.11 standard. It is a medium range wireless technology used to connect devices together. Wi-fi uses radio waves to provide a connection to the internet.

The radio waves are transmitted by a Wi-fi Access Point (WAP) that normally has a wired connection to the internet. Think of how your phone or laptop connects to the internet via the wireless router in your home.

Examples of wi-fi include:

• 2.4 GHz – ultra-high frequency
• 5 GHz – super-high frequency

These numbers refer to two different 'bands' your wi-fi can use for its signal. The biggest difference between the two is speed. Under ideal conditions, 2.4 GHz wi-fi will support up to 450 Mbps or 600 Mbps, while 5 GHz wi-fi will support up to 1300 Mbps.

Wi-fi networks are often protected and usually require a network key (essentially a password) in order to log in. Devices that use wi-fi need to have a wireless adapter to enable them to communicate with the wireless router.

A wireless adapter or wireless network card is a hardware device that converts binary data to radio wave signals. A wireless router is a hardware device that receives the radio signals and routes them along a series of similar devices to their destination.

Advantages of wi-fi:

• Allows you to set up LANs without wires
• Wi-fi enabled devices are now widely available
• Users can log in from anywhere within the wi-fi network using any wi-fi device

Disadvantages of wi-fi:

• Signal strength weakens the further away you are from the router
• The wireless connection may not be as secure as a wired connection
• Wi-fi signal can be affected by adverse weather conditions. Water droplets absorb the 2.4 Ghz radio frequency and partially block the signal (however, most WAPs are located indoors)

Bluetooth communicates using radio frequencies and requires no physical cable connections. It was designed to enable a range of portable devices to connect both to each other and to other, less portable, hardware.

Common uses of bluetooth are sharing data files between mobile phones, or sending audio to bluetooth speakers. It operates over a short range (typically between 10-100m). The range can be affected by obstacles (e.g., furniture, walls etc.), but devices do not need to have a direct line of sight to connect.

Advantages of bluetooth:

• Low cost to set up
• Uses relatively little power compared to other types of wireless connection
• You can easily set up bluetooth networks with other bluetooth enabled devices

Disadvantages of bluetooth:

• Short range
• Low level of security
• Low data transmission rate

Fibre optic cable uses light and consists of glass or plastic wires/cores or filaments bundled together and encased in a jacket. Light is transmitted in pulses which represents of a range of frequencies.

The transmitter in the router sends light pulses representing binary code. When the data is received, it is decoded back to its binary form and the computer displays the data. Each core has a mirror-lined wall which reflects light back along the core (total internal reflection) to minimise signal degradation. The cable can vary in length from a few metres to hundreds of kilometres.

Light is passed through the cable using a transmitter. The transmitter in the router sends light pulses representing binary code. When the data is received, it is decoded back to its binary form and the computer displays the message.

Advantages of optical fibre:

• Supports broadband/multiple data transmissions
• Impervious to electromagnetic interference
• Impervious to corrosion
• Minimal signal loss over distance
• Signal difficult to intercept without destroying it

Disadvantages of optical fibre:

• Fibre optic cable is much more expensive to install than traditional copper cable (although it does last a lot longer)
• Optical fibres require more protection around the cable compared to copper