For B Com

1. INPUT OUTPUT DEVICES
FOR B.COM
Presented By :
Prof. Muhammad Faheem
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Educational
Hub
College
Gujranwala

2. I / O DEVICES
 Provide means of communication between a
computer and user.
 Also known as peripheral devices
because they
act as plug and play devices with computer.
è Input devices are used to enter data from the
outside world into primary storage.
 Output devices provide results of processing
from primary storage to users.
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Hub
College
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3. INPUT DEVICES
INPUT:-
q Anything given to computer such as
Data OR Instructions
is called INPUT.
à Input devices are used to input
data and instructions into computer.
à These devices send data to processing unit.
à EXAMPLE:-
* mouse * keyboard * scanner.
3
Educational
Hub
College
Gujranwala

4. KEYBOARD
 Keyboard is most commonly used input device.
 Data is mostly entered using keyboard.
 Buttons on keyboard are called keys.
 Standard keyboard contains over 101 keys.
 A keyboard contain
* numeric keys * alphabetic keys * function keys
* special purpose keys
 A standard keyboard is normally called QWERTY
keyboard. Because
 Six keys on top row of letters on these keyboards are
Q,W,E,R,T,Y.
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Educational
Hub
College
Gujranwala

5. MOUSE
Mouse is
 Most widely used pointing device.
 Small and light weight input device.
 Used input instructions with pointer on screen.
 Moved on flat surface to control movement of cursor.
 Attached to computer with wire or wireless.
 Very easy to use.
Mouse usually has
Ø Two or three buttons.
Ø These buttons used to perform different tasks.
Ø It may also include scroll wheel to scroll long
documents.
Ø Traditional mouse has a small ball at bottom.
Ø Optical mouse uses light reflection.
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Educational
Hub
College
Gujranwala

6. TOUCH SCREEN
Touch screen is a
 Touch sensitive display device.
 User can touch different parts of screen with
finger.
 Today many touch screens are multi-touch and
can recognize input more than one finger.
Example: user use two fingers to enlarge
image.
Touch screens are
 Commonly used in mobile devices and ATMs etc.
 Some laptop and desktop computers also have
touch screens because the user can interact.
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Hub
College
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7. TRACKBALL
• can be used as an alternative to mouse.
• It has buttons similar to those on mouse.
• It has large rotating ball on the top.
• Body of trackball is not moved.
• The ball is rolled with finger.
• Position of cursor control with ball.
• It takes less space to move than mouse.
• It can also used as separate input device
with desktop computer. 7
Educational
Hub
College
Gujranwala

8. POINTING STICK
 Pointing stick is a pressure sensitive
device.
 It is similar to pencil eraser.
 It exists between keys on keyboard.
 Pointer on screen moves when user
pushes pointing stick.
 It requires no additional space.
 Pointing stick is normally used with
notebook computers.
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Hub
College
Gujranwala
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9. JOYSTICK
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Joy stick consists of a
 Base and a stick.
Ø Stick can be moved in any direction
to move
“ an object around the computer screen”.
Ø Joy stick can perform similar function to
mouse or trackball.
Ø But it is less comfortable and efficient.
Ø Most common use of joystick is for playing
games.

10. Pen Based Computer System
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Pen based system is used to
Ø enter handwriting and marks in computer
using pen-like (stylus).
The user writes
 Words and symbols on screen.
This system uses
• Handwriting recognition software.
• Software translates handwriting characters into
“form that can be stored and processed by
computer”.
 Many handheld computers have pen system.

11.  The data processed into useful information is called
OUTPUT.
à Output devices are used to display
result of processing.
à Most common output devices are
* monitor
* printer
* speaker
* headphone
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Educational
Hub
College
Gujranwala
OUTPUT DEVICES

12. DISPLAY SCREENS
 A display screen is an output device that
“ displays text , graphics and video”.
 It is used to display soft copy output.
There are different types of display screens.
Ø Displays have touch screens that are very popular.
Different displays screens can be distinguished on the
basis of following features.
1. Size
2. Color
3. Resolution
4. Video Display Adapters
12
Educational
Hub
College
Gujranwala

13. PRINTER
 Printer is an output device.
 It prints characters, symbols and graphics
on paper.
 The printed output is called hard copy.
Ø Print resolution is measured in dpi.
Ø Higher dpi produce high quality output.
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Hub
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14. TYPES OF IMPACT PRINTER
-:Dot matrix printer:-
 It is an impact printer.
 It prints when
“ tiny pins on a print head strike an inked ribbon”.
 When ribbon presses against the paper, it creates dots that
form characters and graphics.
 Print head contain 9 or 24 pins.
 Number of pins depend upon the manufacturer and printer
model.
 High number pins produce high quality prints.
 Speed of this is measured in CPS ( characters per second).
 Speed of most printers ranges from 350 to 1100 cps.
 It not produce high quality of output.
 They produce a lot of noise while printing.
 Printing cost is very cheap.
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Hub
College
Gujranwala
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15. TYPES OF IMPACT PRINTER
Daisy wheel printer:-
 It is similar to type writer.
 It uses a print wheel.
 The print wheel is called daisy wheel.
 Each petal of daisy wheel contain character.
 A motor rotates the wheel.
 Hammer strikes the petal against the ribbon when
desired character reaches the paper.
 Daisy wheel printer is slower than the dot matrix
printer.
 It produce output better quality than dot matrix.
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Hub
College
Gujranwala
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16. TYPES OF IMPACT PRINTER
Line printer:-
 It is fast impact printer.
 It prints entire line at a time.
 Its speed is measured in LPM.
 Many line printers prints 3000 lines per
minute.
-:Types :-
* band line printer
* chain Line printer
 It is normally used by mainframe and
microcomputers.
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Hub
College
Gujranwala
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17. Educational
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TYPES OF NON IMPACT PRINTER
Types of non impact printer are as
follows:-
1.Laser Printer
2.Inkjet Printer
3.Thermal Printer

18. Educational
Hub
College
Gujranwala
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TYPES OF NON IMPACT PRINTER
Laser printer:-
o LASER stand for Light Amplification by Stimulated
Emission of Radiation.
o Its working similar to photocopying machine.
o It uses laser beams to burn special powder on the page
to create a permanent image. The powder is contained
in toner.
o Laser printer prints complete page at a time. It is also
called page printer.
o Its printing speed is usually 12 to 45 pages per minute.
o Laser printer prints text and graphics in high quality
resolution.
o A laser printer provides a resolution 1200 DPI or more.

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TYPES OF NON IMPACT PRINTER
Inkjet printer:-
o Inkjet printer is also non impact printer.
o It prints characters and graphics by spraying tiny
drops of liquid ink on paper.
o It prints both black-and-white and color including
photos.
o Inkjet printer provides resolution of 600 DPI or
more.
o Inkjet printers can print from 10 to 35 pages per
minute.
o The print quality of Inkjet printer is higher than
dot matrix printer.

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TYPES OF NON IMPACT PRINTER
Thermal printer:-
o Thermal printer is a printer that uses heat
process to transfer colored dyes or inks to
the paper.
o Thermal printer is the best color printer
and expensive.
o It is widely used to produce very high-
quality color artwork and text.
o Thermal printer provides resolution of 600
DPI or more.