Input and Output Devices

ICT NOTES
2.1 Input Devices and their uses

A. Keyboard
Uses of keyboards
» Input of data into applications software (for example, text into word
processors, numbers into spreadsheets, and so on).
» Typing in commands to the computer (for example, Prnt Scrn, Ctrl+P to print
out, and so on).

B. Numeric Keypad
Uses of numeric keypads
» Automatic teller machines (ATMs), where the customer can key in
their PIN, amount of money, etc.
» Mobile phones to allow phone numbers, etc. to be keyed in.
» Point of sale terminals (POS) in case the barcode reader fails to read the
barcode – the number has to be keyed in manually by the operator.

C. Mouse and Touchpad

Uses of a mouse and touchpad
Almost anything, depending on the software, but includes:
» opening, closing and minimising software
» grouping, moving and deleting files
» image editing, for example, controlling the size and position of a drawing
pasted into a document
» controlling the position of a pointer on the screen to allow selection from a
menu or selecting an icon, and for scrolling up and down/left and right.

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D. Trackerball
Uses of a trackerball
» Can be a good alternative to a mouse for people with
conditions such as RSI.
» Used in an industrial control room environment where it is
faster than a mouse to navigate through process screens.
» Used in some luxury cars to select functions such as radio,
telephone, music, satnav and so on.

E. Remote control
Uses of a remote control
» Televisions, satellite systems, DVD/Blu-ray players and Hi-Fi systems all use
remote controls to alter functions such as sound volume, on/off, change
channels, open the disc drawer, and so on.
» Used to control multimedia systems.
» Used in industrial applications to remotely control processes, stop and start
machinery, etc.

F. Joysticks and driving wheels

Uses of a joystick
» Used in video/computer games.
» Used in simulators (for example, flight simulators) to mimic actual controls.
Uses of a driving wheel
» Used in video/computer games (for example, car racing games).
» Used in simulators (for example, car-driving simulators) to mimic actual
vehicle controls.

G. Touch screens
Uses of touch screens
» Self-service tills, for example, petrol stations, where the user just
touches the screen to select the fuel grade and payment method.
» Automatic teller machines (ATMs) to choose from on-screen options.
» Point of sale terminals such as in restaurants.
» Public information systems at airports, railway stations, tourist offices, etc.
» Mobile phones, tablets and satellite navigation systems.
» Interactive white boards in education.
» Computer-based training (CBT) where answers are selected during on-screen
testing.

H. Scanners
Uses of scanners
» Scan in documents and convert into a format for use in various software
packages.
» Scan in old/valuable documents/books, thus protecting the originals, as well
as producing records in case the paper copies are lost/destroyed (this is also
known as archiving).
» Scan in photographs (not all cameras are digital and therefore photographs
are still printed on paper, requiring conversion to computer format for
storage).

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I. Digital cameras
Uses of digital cameras
» Taking photographs; they still take better photgraphs than smartphones or
tablets due to the use of expensive lenses and dedicated software.
» Used as a data-capture device; for example, as a reversing aid in a car
where small cameras (in the bumpers) help the driver to see their immediate
surroundings.
» Dentists use digital cameras to take photos of a patient’s teeth to help them
diagnose any problems; they are also used to improve colour matching when
doing dental fillings.
» The creation of virtual reality tours around houses, historical buildings,
industrial plants, and so on

J. Microphones
Uses of microphones
» To input speech/sounds to be used in various applications, for example, in
presentations, sampling (in films, music, etc.) and special effects (films).
» Input in voice-recognition software:
– the software converts the speech into text that can be used in, for example, a word
processor or to input commands into a computer
– to recognise commands; for example, some cars now have voice-activated
systems to switch on the lights, turn up the radio volume, etc. (see Chapter 1).
» Microphones can also be used as a sensor to pick up sound (for example, in an
intruder alarm system).
» Used in video-conferencing or Voice over Internet Protocol (VoIP)
applications.

K. Light pens
Uses of light pens
» Selecting objects on CRT screens.
» Drawing on screen (for example, with CAD packages).

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Advantages of using sensors
» More accurate readings taken when compared to human operators.
» Readings are continuous – no break in the monitoring.
» Because it is a continuous process, any necessary action (control system) or
warning (monitoring system) will be initiated immediately.
» Systems can be automatic, removing the need for human intervention
(very important if the process is hazardous or needs precise control/
monitoring).

Disadvantages of using sensors

» Faulty sensors can give spurious results – for example, sensors on the rear
bumper of a car that monitors obstacles; if these become dirty, they may
either not identify an obstacle or give a continuous alarm.
» Most sensors are analogue, therefore they require conversion using an ADC.

2.2 DDE (Direct Data Entry Devices)

Direct data entry (DDE) devices are used to input data into a computer without the
need for very much, if any, human interaction. For example, barcode readers are DDE
and the only human involvement is to point a reader at the barcode. The transfer of the
data to the computer is done automatically.

Direct Data Entry & Associated Devices

Magnetic Stripe readers
• Used to read information on the magnetic stripe
• The stripe contains useful information such as start and
expiry date
• Uses
o Credit and debit cards have magnetic stripes that are used by ATMS or
EFTPOS (electronic funds transfer point of sale) terminal
o Security cards for entering building e.g. hotel rooms
o Travel systems e.g. train and underground tickets

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• Advantages
o Data entry is fast compared with keying in using a keyboard or keypad
o System is error free, no typing involved
Information is secure since there is no typing and the information can’t be read
directly by a person
o Can prevent access to restricted/secure areas
o Magnetic stripes are unaffected by oil water and moisture
o No moving parts therefore physically robust

• Disadvantages
o If the magnetic stripe is damaged the data is lost
o Card needs to be in close contact with the reader
o Since the information is not human readable, they need to find a way
to show the information to the customer (e.g. hotel room number not
printed on cards)

Chip & PIN readers

o The device has a slot where the card is placed, and the chip is read
o A small screen is part of the reader which gives instructions to the
operator
• Uses
o Chip and PIN readers areused where payments are made using cards
e.g. travel agents
Advantages
o Provide a more secure payment system than requiring a signature or
using magnetic stripe, since the PIN typed in must match up with the PIN
stored on the chip
o Provide a more robust system than magnetic stripe since the chip does
not need to be in contact with the reader
• Disadvantages
o Customer needs to be careful when typing in the PIN, so nobody reads it
giving an opportunity for Fraud

Radio Frequency Identification (RFID) Readers

• RFID readers work in similar ways to a bar code reader
• An RFID tag is attached to/inside a surface
• The reader reads the data held on the tag which is then input into the
computer system for processing
• Radio waves are used to transmit data thus can be used through most
materials
• Uses
o Used in retail or supermarkets as barcode alternatives
o Used to identify pets
o Used in passports

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 • Advantages
o Can hold a lot of data
o Can be read from long distances
o Does not require direct line of sight
o Information can be read faster than barcodes
o Can alter information
• Disadvantages
o Thieves can steal information easily
o RFID tags are expensive
o Radio waves can experience interference

Magnetic Ink Character Reader (MICR)

• Magnetic ink character recognition is a system which can
read characters printed in a special ink
• Uses
o Used to process cheques in banking operations – cheque is read using
a batch processing method
• Advantages
o MICR offers great security than OCR since the oriented characters cannot
be altered
o There is no manual input, thus errors are reduced
o If somebody writes over the magnetic ink characters, it can still be read
• Disadvantages
o Only certain characters can be read, and the number of different
characters is very limited
o It is a more expensive method than other methods used for direct
data entry

Optical Mark Reader

• Optical mark recognition is a system which can
read marks written in pen or pencil
• Uses
o OMR devices are used to
read questionnaires, multiple choice examinations papers and other types of
forms in the form of lines or shaded areas
• Advantages
o A very fast way of inputting results of a survey
o Since there is no typing, it is more accurate than keying in data
o OMR is more accurate than OCR
• Disadvantages
o Forms need to be carefully designed to make sure that the
marks/shadings are correctly positioned to gather accurate
information
o There can be problems if forms aren’t filled correctly, sometimes they
must be checked manually before being read by an OMR, this is both
time consuming and expensive.

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Optical Character Reader
• Optical Character recognition is a software that
takes scanned text and converts it into a computer
readable form
• Uses
o Processing of passports and Identity cards
o OCR is used when scanning documents to modify them using a
suitable software
• Advantages
o Much faster data entry system than manually keying in data
o Since there is no manual data entry, the number of errors is
reduced
• Disadvantages
o The system has difficulty reading handwriting
o It is still not a very accurate technique

Barcode readers
• Used to read information in the form of a barcode
• Handheld scanners or wands are very common for
reading barcodes
• Uses
o Used in supermarkets and other shops where the goods are marked
with a barcode
o Used in libraries to scan user’s library card and
barcodes on books (to keep track of books on loan)
o Used as a safety function in many companies to ensure that electrical
equipment is checked on a regular basis
• Advantages
o Faster than keying in information, and fewer mistakes are made
o Used as a way of recording data, can improve safety
o Barcodes enable automatic stock control
o Barcode scanning is a tried and trusted technology
o When an item price is changed, only the central database needs to
be updated, there is no need to change the prices individually on
each item
• Disadvantages
o Barcode scanning is an expensive system to administer since every item in
the shops needs a barcode and every barcode needs to be entered on
the system
o Also, there is a need to invest in the computer technology together
with staff training, which can all be expensive
o The system is not fool proof- barcode can be swapped around on items

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2.3 Output Devices

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