The document discusses various input and output devices used in computer systems. It provides detailed descriptions of common input devices like keyboards, mice, scanners, digital cameras, and microphones. It also covers various types of output devices for displaying and printing data, including monitors, printers, and speakers. The document aims to explain how these devices work and their uses for getting data into and out of computer systems efficiently and accurately.

1. Mr. Abdul Wajid

2. 
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The data or instructions you type into the
computer are called input
Input devices used to get data into a
system.
Get data into a system as accurately, least
amount of time.
It’s a cheap device.

3. 
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Keyboard
Mouse
Tracker ball
Touch sensitive pad
Joystick
Light pen
Touch screen
Graphics tablets
Magnetic Strip Reader
Bar Code reader
Digital cameras
Web Cameras
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OCR
MICR
OMR
Punched Card
Kimball tag
Voice recognition
Microphone
EPOS
EFTPOS
Video digitiser
Scanner
Touch Phone Telephone

4. 
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Keyboard is the oldest and most familiar of all
input devices
Keyboard are intelligent devices and contain
their own chips.
The microprocessor scans the keyboard
hundreds of second to see if a key has been
pressed .
The CPU translate that key and convert into
ASCII code.
A standard keyboard called QWERTY
keyboard.

5. 
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New keyboards, called concept
keyboards, have been
developed for ergonomics
The goal of this keyboard is to
provide comfort and safety.
The user who spends a lot of
time in typing may experience
repetitive injuries of wrist and
hand.
Higher typing speeds can be
achieved.

6. 
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That requires no wires
It is also called wireless keyboards.
It transmits data using wireless
technology like radio waves or light
waves

7. 
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These keyboards make it easy for blind
users to input data into a computer
There are also keyboards with large
coloured keys that are easier to see.
Each key is about one inch square.

8. 
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Most computers come with a keyboard
supplied
People are used to using keyboards to
enter data, they need very little training
A skilled typist can enter data very
quickly
Specialist keyboards are available e.g.
ergonomic, gaming keyboards

9. 
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It is easy to make mistakes when typing
in data
If you can't touch type, it can be time
consuming to enter data
Keyboards are not suitable for creating
diagrams
Disabled people often find keyboards
difficult to use
Excessive use can lead to R.S.I.

10. 
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That translate its movement on the
desktop into digital information.
Moving the mouse produces movement
of cursor or the pointer on the screen.
The mouse is also provided with buttons
to press.

11. 
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Movement of ball bearing is used to
produce electrical signal.
Small lights under the mouse are
reflected on the photoelectric cells.

12. 
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To select options from a menu or form a
set of icons
To position the cursor when editing text
or using a design package.
To draw shapes.
It selects a position on the screen more
quickly than is possible with a keyboard.

13. Is similar to tracker ball.
 Is a device which enables the user to control
movement on the screen by a small lever.
 The lever can be moved in any direction.
 Some joysticks give more control on the screen.
Uses
 Controlling objects in computer games
 Producing graphics
 Scanners in hospitals
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14. 
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Is a pen shaped device, held in the hand
which can detect the presence or
absence of light
It is connected by the cable to a
recording device or to a computer or
computer terminal.
Electrical signals are sent along the
cable indicating whether or not light of
sufficient intensity is being sensed.

15. To detect bar codes
 To indicate a point on the screen
 It removes the need to type or write.
 It is faster than typing.
Disadvantage:
It can only record the presence or absence
of light.
It only works with software written for it.
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16. 
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Is also known as digitizing or digitizing
pad.
The digitize data means to convert it from
analog form to digital.
A design is put on the board and its
shape is traced out with the stylus.
Electrical signals sent to the computer
record the position of the stylus.
Encoding the picture into binary form

17. 
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It can be used to digitize drawings with
great accuracy.
Reproducing drawings and designs
Producing layouts of printed circuit
boards.
Digitizer Maps.

18. 
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Is a small, flat surface over which the user
moves his finger.
The movement of the finger moves the cursor
on the screen.
A touch pad also has one or more buttons near
it .
These buttons like mouse buttons.
Touch pads are commonly used with notebook
computers

19. 
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Is a video display screen that receives
input from the touch of finger
Examples
ATM
Petrol Pumps

20. Is a short length of magnetic tape stuck on the
surface of a tag, card or document.
 On plastic tags or cards the strip is sealed in.
 Tags with stripes identify the item they are
attached to.
Examples:
 On credit card
 On bank cards
 A phone Card
 Cash issue Terminals
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21. It is simple to produce.
 It is not easily damaged.
 It stores a large no of characters.
Disadvantages
 The data can be changed or erased by
magnetic field.
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22. Is set of parallel printed lines of differing
thickness, which represent a number.
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The number represented by the bars is also
printed above or below the bar code.
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When bar code are used on shop goods, the
number coded identifies the product and have
following information
1. Country of region
2. Manufacturer
3. An item number for the product.
Examples:
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Used in Barcodes
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Library System
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Warehouse stock
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23. Printed easily
 The type of item or its price does not
have to be repeatedly written down or
typed.
Disadvantages:
 bar codes cannot be changed and thus
there are unsuitable prices.
 Bar codes only be read by machine.
 Only numbers can be coded in this way.
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24. 
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Is a technology that reads typewritten ,
computer printed or handwritten documents.
It translate the image into a form that can be
recognized by computer.
OCR devices read printed characters using
OCR font.
An OCR device determines the shapes of
characters by detecting patterns of light and
dark.

25. 
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In department stores
To scan financial documents such as
company

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It is also called mark sensing device.
It uses light to scan input data to convert it into
electrical/digital signal.
The signals are then sent to the computer for
further processing.
Examples
Voting ballot
Multiple choice answer sheet marking
Enrollment forms

28. 
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In OMR there is typing involve so errors and
takes time is less
Reduces the cost of inputting large amount of
data
The method is useful when results of the test
are needed very quickly
Disadvantages
Readers are very expansive
Only certain fonts are acceptable.
There is high rejection rate

29. 
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Characters are printed
using an ink containing
iron oxide.
As the document passes
into the reader the ink is
magnetized, so that the
character shapes can
then be recognized
electrically.

30. 
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It is used by banks industry for check
processing.
Each check contains MICR characters at
the lower left edge.
These characters represent check
number ,bank number and account
number
Cheque number
Branch code
Account number

31. Documents can still be read when folded,
written on
Disadvantages
 Readers are very expansive
 Only certain fonts are acceptable.
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32. 
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Contains holes in different positions which
mean something when they are read by a
reader.
Punched cards were the main method of
entering data into computers.
Example:
The clock card which is used to record the
hours a person works so that wages can be
calculated.

33. 
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Kimball tags are the small cards with
holes punched in them that you see
attached to clothing in certain shops.
When you buy the goods, one of the tags
is removed and sent for processing to a
computer centre.

34. 
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Stock is reordered without any writing or
typing the data.
Disadvantages:
They are small and are easily mislaid.

35. 
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Using a microphone human speech is
coded into a sequence of electrical
signals.
The computer searches a set of stored
patterns for the sound which has been
input
It is now popular for inputting data into
word processing or database packages.

36. 
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Useful for handicapped people with
limited movement
No typing or data preparation is
necessary.
Disadvantage:
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Few words can be recognized and the
error rate is high.
Not suitable in noisy places.

37. 
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Is used for input device for a speech
recognition system.
The voice pattern of user is then
converted into instructions to the
operating system or application software
or text.
Uses as voice mail messages

38. 
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Are the cash registers which act as the
terminals to a main computer system
Providing customers with item used in
bills.
Give useful management information

39. 
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Similar to EPOS terminal but some
additional features.
They are able to transfer funds from your
bank account directly to a store’s switch
card called a debit card.
Example:
Switch card

40. 
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You can use it instead of a cheque.
Faster method of payment
Money is instantly transferred into its account.
You can also get cash back using your debit
card.
Disadvantage:
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They may be stolen and they are said to
encourage people to spend more money.

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Is the combination of hardware and Software
that converts an analogue video signal into a
digital signal in computer’s memory
Is used to convert a frame from a video
sequence into a picture
Each frame from the video is converted using
video digitiser.
It may be played back in any required
sequence.
Is also called image grabbing or frame
grabbing
Take up a lot of main memory and when stored
use a large amount of disk space

42. 
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Digitiser pictures Can be printed in a
magazine or document
To make television adverts and to
produce pop videos.

43. 
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Read data or information from the source
Source could be written document, a
price tag, a graphics image , or
photograph
To scan text or images which
manipulated in some way before being
printed

44. 
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Optical Scanner
Optical Reader

45. 
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It is a light sending input device.
The scanner image depend upon resolution
Image will be sharper if the scanner provides
high resolution
it provide OCR Software
Different types of Optical Scanner are
Flatbed Scanner
Sheetfed Scanner
Handheld Scanner

46. 
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Is used to store, picture in digital form.
Store images using different ways like floppy
disk, memory stick, mini CD ,PC Card and
micro device.
Can be connected to a computer easily through
USB port.
Image resolution for digital camera measured
by megapixels.
Higher resolution photo takes up more memory
.

47. 
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No film is needed
No expensive developing costs
Pictures are in digital form so it can easily
sent over the internet
You can adjust the size of image

48. 
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Is simply a digital camera that
is used to capture still images
and video images
These images can then be
transmitted to a computer
where they are stored in
graphics format
Pictures can be used on the
websites
Camera placed on top the
screen such a system allow
video conferencing

49. 
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Advertising
Checking on children in nurseries
Checking on the weather on the other
part of the world

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Having a different tone of each number
when pressed key
Using these different tones that the
numbers dialed are recognized and
routed to correct telephone
Can be used as a data entry device
Home banking system use touch tone
telephone

51. 
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Output device provide results in a
suitable form after data processing.
Output devices are used to get data out of
a system.
They should be able to do this as
accurately and quickly as possible, and
with the minimum of human intervention.

52. • Visual devices (including Visual Display Units
[VDUs], screens, and monitors)
• Hard copy devices (including ink jet printer,
laser printers, dot-matrix printers, and plotters)
• Sound devices
• Computer controlled devices (including robots)

53. 
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Most common output deice
It is known as display screen
The output display by monitor is called
soft copy so it is ideal for showing the
results from an enquire where no printed
is needed.

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Size
Color
Resolution
Video Display Adapter

55. 
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CRT
Flat Panel Monitors
Touch screen Monitors

56. 
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Creates the image on the screen through
electronic beam
This is same type that is use in Television
It consists of one or more guns
These guns generate red ,green and blue
(RGB) colors.

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LCD screens are most often seen on
portable or laptop computers
These are used in these applications
because they are small and light.
Also used where space is at the premium.
The molecules this substances line up in
such a way that the light behind the
screens and creates an image.
Use in banks and Multinational
companies

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Larger than VDU and have greater
resolutions
lines on the screen don’t look as through
they are made up of lots of tiny dots.
Are often used in conjunction with light
pens

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It prints character ,symbols and graphics
on paper.
Print resolution is commonly measured in
dots per inch (dpi)
Different types of printer are
Impact Printer
Non Impact Printer

60. 
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Its act like a typewriter
It prints characters or images by striking
a print hammer or wheel against an
inked ribbon
Dot matrix printer
Line printer
Daisy wheel Printer

61. 
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It produces printed images when tiny pins on a
print head strike an inked ribbon
When ribbon pressed against the paper, it
creates dots that they form characters and
graphics
Which can transfer print through layers of
paper.
Able to print multi-part sheet where
It generates lot of noise ,its print quality is not
good

62. 
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Is a fast impact printer
It prints a entire line at a time
Its speed is measured in line per minute

63. 
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Similar to typewriter
Uses print wheel
A motor rotates the wheel.
Its slower than Dot matrix but better in
quality

64. 
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Prints characters and graphics on a piece
of paper without striking the paper.
These printers are faster than impact
printers
Inkjet printer
Laser printer
Thermal printer

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It prints characters and graphics by spraying
tiny drops of liquid ink on paper
The print head of an inkjet printer consists of
nozzles
It has two cartridges black and white
These printers can produce quality text and
graphics in both black and white color
slower than laser printer but faster than dot
matrix printer
They can print 1 to 6 pages per minute
Cheaper in price
Satisfactory in color

66. 
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Creates image on the paper by the laser
beam
Also called page printer because they
print complete page at a time
It contain toner
Throws magnetic powder on paper in
the form of microscopic dots

67. 
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Print a page at a time so it is fast and it
print pages 10ppm
They produce high quality of text and
graphics
They are quiet in operation compared
with dot matrix
Equipped with paper trays for both the
input and the output papers

68. 
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Are more expensive than dot matrix or
ink-jet printer
They are quite large and can take up lot
of disk space
Quite complex so the repair bills can be
high
Multi part stationary cannot be used

69. 
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Is a printer that uses heat process to
transfer colored dyes or inks to the paper
Is the best color printers currently
available but it is very expensive

70. 
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Is an output device that is used to
produce image quality graphics in
variety of colors
Used to create maps, architecture
drawings, graphs and charts
A plotter works by drawing lines on
paper using pens held in a mechanical
arm
It may be in form of
Flatbed Plotter
Drum plotter

71. 
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Is an output device that is used to
produce image quality graphics in
variety of colors
Used to create maps, architecture
drawings, graphs and charts
A plotter works by drawing lines on
paper using pens held in a mechanical
arm
It may be in form of
Flatbed Plotter
Drum plotter

72. 
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Used to plot or draw images.
It contains pens for drawing images.
The paper is placed on table like surface
Software instructs the pens to move down
on the paper

73. 
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Uses a rotating drum
or cylinder
The drawing pens are
mounted on the drum
The pens move to the
left and right as the
drum rotates
Advantage of drum
plotter is that the
length of the plot is
almost unlimited

74. 
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Visually people find the spoken word
from the computer
Special software is used for this process
In a word processor each letter is typed
and it can hear with headphone.

75. 
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An audio device translate audio
information from the computer into
sounds that people can understand
Speakers
Headsets

76. 
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Sometimes the output from one computer system can
simply be a series of electrical signal
In this case one computer is being used as a terminal
and work that is done sent as electrical signals
Electrical signals can be output and used to control all
kinds of devices such as
Heating system
Alarms
Robots
Actuators
Computer aided manufacturing (CAM)
Computerised numerical control (CNC)

77. A typical computer
controlled device
used in computeraided
manufacturing – a
robotic arm