1. Wireless Communications Standard ‘wired’ networks are connected together using copper cables that carry data around the network in the form of electrical signals. In some circumstances laying cables may be inconvenient or even impossible. The answer may be to implement a “wireless” network to move the data around.

2. Wireless Communications Wireless networks use radio signals to communicate between workstations, file servers and hubs. A popular name for this kind of network is “Wi-Fi” Special Note: Wireless can also be interpreted as “wire-less”, which means to create a network without wires. In this case, a “wire-less” network may be using infra-red or even lasers to communicate – this is much rarer than using radio.

3. Wireless Communications Each workstation and file server on a wireless network has a transceiver and small antenna to send and receive data. Information is relayed between transceivers in the same way as if they were physically connected.

4. Wireless Communications – in the home  Think about how you may want to use computers at home. Here is a possible set-up: Kids’ Games \ Homework PC Upstairs Mom’s laptop in living room Question: How to connect them together? Dad’s PC Desktop in the den with an internet connection

5. Wireless Communications – in the home  Making use of a wireless network at home: Dad’s PC Desktop in den with an internet connection Kids’ Games \ Homework PC Upstairs Mom’s laptop in living room Answer: A wireless network.

6. Wireless Communications – in the home  Advantages (compared to a wired network):  No need to lift floorboards to lay cable  The computers can be anywhere in the house or even the garden on sunny days!  Simple to add a new machine to the network e.g friends bringing along a laptop to share holiday photos etc.

7. Wireless Communications – in the home  Disadvantages (compared to a wired network):  Can be more expensive, especially if there are many machines to connect.  You have to be very careful about security – your data is broadcast well beyond the house walls!  Can be prone to electrical interference e.g storms or something else sending similar radio signals such as a faulty car passing by.

8. Wireless Communications – in the workplace  There are often dozens perhaps hundreds of computers connected in an office environment  Most of these are connected using a wired network because:  The network was planned as part of the office from the outset  Most machines are fixed in place at a desk

9. Wireless Communications – in the workplace  But it can be convenient to connect mobile laptops to the network. In this case a wireless hub is the answer.  The wireless hub is hard wired into the network and laptops connect to the wireless hub by Wi-Fi

10. Wireless Communications – in the workplace  Why it is convenient to use a wireless network as part of a wired office? Tom and Harry are salesmen on the move. So when they visit the office, they need to connect to the office network Samantha is presenting her work in a meeting room via a light projector. She connects to the shared network through a wireless link.

11. Wireless Communications – in the workplace  Other uses of a wireless network at work Joe is a civil engineer, and needs to connect to the office network to bring up some plans Portakabin office

12. Wireless Communications – in the workplace  Other uses of a wireless network at work There has been a natural disaster and aid workers are collating all kinds of information in the field – a wireless network is the answer. Emergency Office

13. Wireless Communications – in the workplace  Advantages of a wireless network at work  Excellent for connecting visiting employees.  Convenient for meeting rooms.  Useful for people in the open air (but near an office)  Easy to add temporary machines to the network without having to lay cables  Excellent for networking temporary offices e.g Press office at a national event.

14. Wireless Communications – in the workplace  Disadvantages of a wireless network at work  Security is one of the biggest issues as network data can be highly confidential.  Not as reliable as a wired network – prone to electrical interference  Can be difficult to diagnose network problems.  More expensive to connect many machines compared to cable.

15. Wireless Communications - Other Advantages of Infra-Red  Immune to electrical interference  Much harder to eavesdrop as you have to be within line of sight  Simple to set up. Disdavantages of Infra-Red  Every machine has to be line of sight  Cannot work through walls  Only works well over a short distance

16. Wireless Communications - Bluetooth A radio technology designed to operate mainly over a short range – a few metres. Bluetooth is a specific standard and so devices designed to be ‘Bluetooth’ compatible are guaranteed to work together (unlike Wi-Fi which has a number of ‘standards’) Not as fast as Wi-Fi. Typically 300kbps compared to 54Mbps for WiFi Consumes less power and so devices running on batteries can work for longer.

17. Wireless Communications - Bluetooth Mainly used to allow devices to communicate within a short distance.  Hands-free mobile phones  PDAs  Laptops  Printers  Cameras  Keyboards  Domestic machines – Microwaves, Fridges etc.

18. Wireless Communications – Technical details

19. Wireless Communications - Other Infra-red. This is the same technology as an ordinary remote control – except the devices work in both directions – and much faster. Hubs and computers use an infra-red transceiver Most often used over very short distances. For example to synchronise a PDA with a PC. Can be used in an Office space