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Time: 20 hours
Level: Introductory
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 Introduction Resource- This unit looks at communication systems where devices are the main players, passing information to and from each other and possibly acting on that information to produce some kind of outcome. In these...
| | | | | 1 Communication between devices
- 1.1 Getting an overview Resource
- This section starts with an article from a technical journal – the sort that is read by academics and professionals working in a related technical field. It sets the scene for some of the technologies...
- 1.2 Skimming to get an overview Resource
- A well-structured document usually contains a number of clues about its contents. Skimming is the practice of finding and using these clues. These are:
- 1.3 Skimming – an example Resource
- We'll shortly be asking you to skim an article which appeared in the Spring 2003 issue of a journal called IEEE Technology and Society Magazine. ‘IEEE’ is usually referred to as ‘i-triple-e’ and stands...
- 1.4 Communicating devices Resource
- We would like you now to think about a simple ICT process you are already familiar with – the process that starts when you click the Print icon on your computer's word-processor screen. For now, imagine...
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- 2.1 Introduction Resource
- This section discusses methods of representing data as it travels from device to device, and some of the processes acting on it during its journey. You will be introduced to a way of expressing large numbers...
- 2.2 What are signals? Resource
- To convey data from one point to another we need to represent the data by means of a signal. We can think of a signal as a deliberate variation in some property of the medium used to convey the data. Some...
- 2.3 Electromagnetic radiation Resource
- To help explain the nature of the waves of energy known as electromagnetic radiation, visualise a pond into which a stone has been thrown. If the state of the pond is ‘frozen’ at an instant in time, the...
- 2.4 Scientific notation Resource
- To express a number in scientific notation the first stage is to divide it successively by 10 until it is reduced to a number that is less than 10. For example, to express the number 4865 in scientific...
- 2.5 Working with scientific notation using the Windows calculator Resource
- Most electronic calculators will enable you to perform calculations on numbers expressed in scientific notation. This section will take you through an exercise using the Windows calculator to perform the...
- 2.6 Modifying the medium to carry the message Resource
- Earlier we said that we can think of a signal as a deliberate variation in some property of the medium used to convey the data. Such variation needs to be done in a meaningful way. For example, think of...
- 2.7 Propagation delay Resource
- The time taken for a signal to travel from its source to its destination is known as propagation delay. This is derived from the verb ‘propagate’ which in a physics context means ‘spread’ or ‘travel’....
- 2.8 Attenuation and distortion Resource
- As a signal travels from one device to another it has two problems to overcome. The first is that it gets weaker the further it travels, because some of its energy is absorbed by the transmission medium....
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- 3.1 Introduction Resource
- This section starts by broadly classifying different types of network, first by the nature of the communication links used to connect devices and then by a network's geographical spread. It then examines...
- 3.2 Wired networks – principles of operation Resource
- Each node in a network needs processes to control the flow of data over the network. These processes are carried out by a network interface card (NIC), which provides the interface between the node and...
- 3.3 Wired network configurations Resource
- Network nodes can be connected together in different arrangements known as topologies. We are going to describe four common topologies that you may come across.
- 3.4 Protocols and standards Resource
- You have already met the idea of protocols in Section 1 – rules to govern how information is sent, transmitted and received. Protocols can be explained using an analogy with the way people talk to each...
- 3.5 Establishing Ethernet standards Resource
- The first Ethernet network was developed in the early 1970s, long before the days of the World Wide Web and personal computers (PCs). It was designed by researchers at the Xerox Palo Alto Research Centre...
- 3.6 Routers Resource
- One type of network device we haven't mentioned is a router. This is because a router generally works at the edge of a LAN rather than within it. A router can operate at a level that is independent of...
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- 4.1 Introduction Resource
- The focus of Section 3 was on LANs that use some kind of physical medium (for example, copper wires or fibre-optic cables) to connect together network nodes. In this section we'll be examining wireless...
- 4.2 Basic principles of wireless transmission Resource
- I've never quite lost the sense of wonder at the way information can be transmitted with no visible link between the sender and recipient. When I was a child I used to think that sound came through the...
- 4.3 Regulation Resource
- Increasing demand for wireless technology means that the radio frequencies must be carefully managed and allocated by governments to satisfy all the different users and to prevent interference between...
- 4.4 An introduction to WiFi Resource
- WiFi (from ‘Wireless Fidelity’) is used to connect devices together in one of two network configurations known as ‘ad hoc’ and ‘infrastructure’. We shall explain these terms shortly. (As a starting point,...
- 4.5 WiFi network structure Resource
- A WiFi network can operate in one of two different modes: ad hoc mode or infrastructure mode
- 4.6 WiFi stations Resource
- A WiFi station determines whether it is in range of an AP by transmitting an enquiry, known as a probe request frame, and waiting for a response. If more than one AP responds, the station will choose to...
- 4.7 WiFi data rates and operating range Resource
- Just as for Ethernet, developments in technology have increased the achievable data rates since the first WiFi standard was developed in 1997. At the time of writing, the latest WiFi standard to be published...
- 4.8 WiFi – a summary Resource
- To test your understanding of what you have read so far about WiFi, say whether each of the statements below is true or false.
- 4.9 Bluetooth Resource
- The driving force for the development of the Bluetooth standard was to eliminate the need for connecting wires between local ICT devices such as keyboards, monitors, printers, PDAs (Personal Digital Assistants),...
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- 5.1 Introduction Resource
- In many situations, more than one technical solution is possible. It could be that none of them provides a completely ideal solution; each is likely to have its own merits and drawbacks, and often a compromise...
- 5.2 Comparing WiFi and Bluetooth Resource
- We have used Table 3 to help us make a comparison between WiFi IEEE 802.11g and Bluetooth. Try to complete the empty cells yourself from the information we have given about these two technologies. There...
- 5.3 An introduction to competing technologies Resource
- Look again at Table 4. If I simply wanted to connect my computer and my mouse wirelessly, would I use WiFi? If I wanted to connect together six or seven laptop computers so that they could share information...
- 5.4 Set-up, maintenance and power requirements Resource
- Issues for set-up and maintenance include:
- 5.5 Security Resource
- Because wireless signals travel in free space, they can be picked up by any device in range equipped with a suitable radio receiver. This has implications for the security of data on a wireless network,...
- 5.6 Reliability and usability Resource
- In this context we will define reliability as the ability of a technology to perform its intended function, without failure, under stated conditions and for a stated period of time. It is beyond the scope...
- 5.6 Structuring information Resource
- As you completed the table in Activity 20 you were probably skipping back and forth between the subsections on ‘WiFi’ and ‘Bluetooth’ in Section 4. Did you notice that we used a rather different way of...
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- 6.1 Introduction Resource
- Our discussions of Ethernet, WiFi and Bluetooth have provided you with an introduction to some fundamental principles of wired and wireless networks. This section builds on these general ideas. Up to this...
- 6.2 Devices in the home Resource
- Take a mental ‘walkthrough’ of a typical morning in your own home, making a note of all the events and activities that involve electrical devices!
- 6.3 Devices for automatic control Resource
- Sensors and actuators were mentioned in the introduction to the article, Networked microsensors and the end of the world as we know it, that you read in Section 1. Sensors are devices that measure some...
- 6.4 Signal accuracy Resource
- In the Networked microsensors and the end of the world as we know it article, the author talks about sensors being able to link the ‘world of events’ with the ‘electronic world of computers, processes...
- 6.5 Smart home networks Resource
- Some devices in a smart home may need to communicate information about the environment (for example, information about light, heat, humidity, sound, movement, water levels, etc.). They may also need to...
- 6.6 ZigBee Resource
- Development of the ZigBee standard is the result of a group of interested parties coming together to form the ZigBee Alliance. When approved it will be an open standard sitting within a subset of the IEEE...
- 6.7 Benefits of living in a smart home Resource
- I can think of a number of possible benefits – apart from the obvious one about relieving me of the tedium of performing a lot of routine tasks. The first one I thought about was the potential saving in...
- 6.8 Drawbacks of living in a smart home Resource
- One of the issues I thought about was privacy. How would the elderly or infirm feel about being monitored in their own homes? How would teenage children at home feel about being under the constant eye...
- 6.9 The personalised home Resource
- In the extract from The Road Ahead, quoted at the beginning of this section, Gates makes reference to ‘an electronic pin to clip to your clothes’. This pin appears to have the ability to communicate to...
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- 7.1 Introduction Resource
- This section continues with the theme of networked devices by looking at a system of electronic tagging known as Radio Frequency Identity (RFID). In this system, an electronic tag is attached to an object...
- 7.2 An overview of RFID Resource
- The technology behind RFID is relatively straightforward and has been in use in some form for many years. You may have even used it yourself or seen it in use – for example in a ‘proximity card’ entry...
- 7.3 RFID technology Resource
- There are three main components in an RFID system:
- 7.4 Understanding RFID tags Resource
- An RFID tag consists of a microchip and an antenna and some kind of encapsulation, such as epoxy resin, to bind the two together and protect them. Tags come in a variety of shapes and sizes (Figure 20),...
- 7.5 Active and passive tags Resource
- Read the extracts below. Using the information they contain, make notes about the main differences between active and passive RFID tags. You will get more out of this exercise if you make a serious attempt...
- 7.6 Researching information about RFID tags Resource
- What is the smallest RFID tag currently available? Use the Web to see what you can come up with but don't spend longer than 10 minutes on this activity. (Hint: using ‘smallest RFID tag’ as the search term...
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- 8.1 Introduction Resource
- This section continues with the work started in Section 7. Here you will build on your research to look at some recent applications of RFID and some of the issues surrounding its deployment.
- 8.2 RFID applications Resource
- As we pointed out in Section 7, the driving force for RFID development is coming from major retailers who want to track goods as they travel through the supply chain. Their purpose is to reduce the manual...
- 8.3 Issues and concerns about RFID Resource
- As you've seen, RFID tags can be very small devices – certainly small enough to be inserted unobtrusively under the skin or thin enough to be incorporated into a paper label. Their size (both current and...
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- Unit summary Resource
- In this unit, the emphasis has been on devices communicating with each other in networks. You were introduced to some general principles about signals and networks, and the differences between wired and...
| | | | | References and Acknowledgements | | |
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