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