AS ICT
Portable Communications Devices
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
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
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
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)
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
Accelerometer – senses tilt, orientation, angle
GPS Touch screen technology Apps Email/internet Intelligent maps Memory:
SD (Secure Digital) cards SDHC (SD High Capacity)
Mainly used for personal/business calls
Useful in remote areasCan be used with a satellite
dish if landline is not available
Convenient way of sending/receiving urgent messages
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
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
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
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
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
The same as a standard DVD player, but with a built-in screen
Easy to carryUsually used for personal use rather
than businessUsed in cars/on holiday
Small & compactCan also play music
from CDs
Screen is low resolutionQuality of viewing can be
poorScreen is small, so can be
difficult to viewDifficult for more than one
person to watch at a time
Can store thousands of tracks of music
Can store downloaded TV shows/music etc
Very compactCan hold up to 100 GB of dataCan be connected to speakers
to enhance outputBattery can be recharged while
connected to a PC
Depends on the manufacturerMay be:
Small hard disk Microdrive Flash memory
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
Screen is low resolutionQuality of viewing can be
poorScreen is small, so can be
difficult to viewDifficult for more than one
person to watch at a timeLow quality earphonesMenu-based interface
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
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
Satellite 1
Satellite 3
Satellite 2
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” etcA screen shows your position in relation to the road network
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
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 smallSometimes recommends
unsuitable roads
LaptopsPortable, mobileSmall & light BUT
Just as powerful as a desktop PC now Integrated keyboardPowerful batteryWifi internetCan work anywhere
Become heavy after a whileCan be stolenBattery – may need rechargingSome people find the keyboard &
touchpad difficult to useSome do not have a CD/DVD drive
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
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
Uses radio waves to connect devices
Maximum distance between communicating devices is 10m
Data transfer rate is slow – 1Mbit per second or less
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
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
Data transfer rate is much slower than wifi
Covers much smaller distances than wifi
Obstacles between the communicating devices can prevent connection