AS ICT

1. AS ICT Portable Communications Devices

2. Objectives: You must be able to identify a range of portable communication devices and suggest suitable uses for them. These include: • Mobile phone networks • Mobile phones • Portable DVD players • Portable hard disk players • Portable media players • Global Positioning Systems • Satellite Navigation Systems • PDAs • Bluetooth Devices

3. Mobile phone networks • Mobile phones communicate by using towers that are located in many networked cells. • These towers (masts) allow the transmission of data throughout the mobile phone network. A network of mobile phone cells

4. How the Mobile Phone Network works • Each tower transmits within its own cell • When you get to the edge of a cell the signal gets weaker • This is recognized by the network, so • The phone picks up the signal in one of the adjacent cells

5. Mobile phones • Phones work using the transmission of electromagnetic radio waves. • Each phone has a transceiver • Can transmit or receive data from the nearest tower (this must be within 10km of the phone)

6. Features • Can make or receive calls anywhere providing you are in range of a mast • SMS messages • Audible alert when a message arrives • Contacts list • Automatic dialing • Caller ID • Many have cameras

7. Other features of mobile phones • Accelerometer – senses tilt, orientation, angle • GPS • Touch screen technology • Apps • Email/internet • Intelligent maps • Memory: • SD (Secure Digital) cards • SDHC (SD High Capacity)

8. Advantages • Mainly used for personal/business calls • Useful in remote areas • Can be used with a satellite dish if landline is not available • Convenient way of sending/receiving urgent messages

9. Advantages • SMS messages can be used to convey urgent messages without interrupting business meetings • Can be used while travelling if public phones are unavailable • Can be used to send photos/ video footage

10. Disadvantages • Cost more to use than a landline • Quality of photos can be poor • Can lose connection if the signal is weak or drifting • Display is small compared to other devices • Limited battery life

11. MPT and computers • Mobile Phone Technology can now be used by computers to allow internet access. • A USB network device allows the computer to connect to the mobile network. Very convenient BUT • Slow connection speed • Expensive to buy • Monthly contract • Download limits apply

12. WAP • Early mobile phones could only be used to send and receive calls and SMS. • Wireless Application Protocol allows smaller handheld devices to access cut-down/ simplified web-based content

13. WAP • The wireless device has a ‘microbrowser’ • Your device connects with a service provider • Your website request is sent to a gateway server • This retrieves the information using HTTP and encodes it as WML

14. Portable DVD players • The same as a standard DVD player, but with a built-in screen • Easy to carry • Usually used for personal use rather than business • Used in cars/on holiday

15. Advantages • Small & compact • Can also play music from CDs

16. Disadvantages • Screen is low resolution • Quality of viewing can be poor • Screen is small, so can be difficult to view • Difficult for more than one person to watch at a time

17. Portable Media Players • Can store thousands of tracks of music • Can store downloaded TV shows/music etc • Very compact • Can hold up to 100 GB of data • Can be connected to speakers to enhance output • Battery can be recharged while connected to a PC

18. Data storage • Depends on the manufacturer • May be: • Small hard disk • Microdrive • Flash memory

19. Advantages • Can be used for downloading music/ radio programs • Can be used for downloading/storing TV shows, movies etc • Can be used for downloading data from the internet or transferring data from one computer to another

20. Disadvantages • Screen is low resolution • Quality of viewing can be poor • Screen is small, so can be difficult to view • Difficult for more than one person to watch at a time • Low quality earphones • Menu-based interface

21. GPS • Global Positioning satellite systems can pinpoint your location, give directions to your destination and provide information about nearby businesses. • In-car GPS is often referred to as a satellite Navigation system

22. How GPS works • Satellites surrounding the earth transmit data – this includes the satellite’s position and time • Embedded computers receive and interpret these signals • The exact location of the device is calculated based on the data from at least three satellites

23. How GPS works Satellite 1 Satellite 2 Satellite 3

24. How GPS works • The on-board computer contains pre-stored road maps • The phone (or car)’s exact location (based on the satellite positioning) is shown on the map • You are given verbal directions, eg “turn left in 100 metres” etc • A screen shows your position in relation to the road network

25. Advantages of GPS • No need to consult maps while driving – safer • Warns about road closures/one way streets etc • Up to date information about traffic congestion or accidents (these are fed to the device using radio waves) • Location of speed cameras • Gives fastest route + alternate routes • Useful info eg fuel stations • Estimated time of arrival

26. Disadvantages of GPS • Maps MUST be kept up to date, otherwise they can give incorrect instructions • Loss of satellite signal can cause problems • GIGO – incorrect start/end positions will cause the system to give incorrect information • Display is very small • Sometimes recommends unsuitable roads

27. Other devices: Laptops • Portable, mobile • Small & light BUT • Just as powerful as a desktop PC now • Integrated keyboard • Powerful battery • Wifi internet • Can work anywhere

28. BUT • Become heavy after a while • Can be stolen • Battery – may need recharging • Some people find the keyboard & touchpad difficult to use • Some do not have a CD/DVD drive

29. PDAs • Personal digital assistant • ‘Electronic organizer’ • Cut down versions of main Office software • Can synchronize with PC/Laptop • Access internet • Send email • Play games • Diary/calendar function • May have built in or onscreen keyboard

30. Tablet computers • Small, compact, portable • Single-task OS, so limited in function • Internal battery (needs charging) • Can change orientation of screen • No CD drive • No support for screen – you have to hold it

31. Bluetooth Devices • Uses radio waves to connect devices • Maximum distance between communicating devices is 10m • Data transfer rate is slow – 1Mbit per second or less

32. Bluetooth Uses • Communication between mobile phone & headset (so drivers can talk while driving) • Connecting mouse/keyboard/printer etc to PC • Data transfer between devices eg photos from mobile phone to laptop • Connecting wireless controllers to games consoles

33. Advantages • Can be used for a variety of applications, whereas wifi is only used in LANs where cables would otherwise be used • Cheaper hardware requirements than wifi • Consumes less power than wifi

34. Disadvantages • Data transfer rate is much slower than wifi • Covers much smaller distances than wifi • Obstacles between the communicating devices can prevent connection