INPUT & OUTPUT Devices
CHAPTER II
“The devices used in computer system
INPUT
& OUTPUT
Devices
to enter data
into a computer
or
extract data from a computer are
known as I/O devices “
INPUT & OUTPUT Devices
Input/output devices are used for communication with the computers. Thousands of
kinds of I/O devices are available today and the number is growing rapidly. A few of
the more common ones are listed below:
Keyboards as Input Devices
 QWERTY keyboard
 Dvorak keyboard
 alphabetical keyboard
 chord keyboard
 numeric keypad
A keyboard designed for speed typing.
keyset or chorded keyboard (chord
keyboard or chording keyboard) is a computer
input device that allows the user to enter
characters or commands formed by pressing
several keys together, like playing a "chord"
on a piano.
[Mustillo]
Ergonomical Dvorak Keyboard

virtual keyboard
A virtual keyboard is also called
a projection keyboard.
http://www.ergocanada.com/images/dvorty_2001dqe.jpg
Input Devices
Keyboard
• Ergonomic keyboards
• Compact Keyboard
• Multimedia and Gaming Keyboards
• Virtual Keyboards
Point and Draw Devices
Mouse
• Mechanical
• Optical
Joystick
Trackball
Digital Pad
Mouse Pen
Track Pads
Image Scanner
Mouse Pen
Digital Camera
Hold it like a pen, draw, sketch,
create and mouse on a pad, fits
in your pocket, is wireless and
works for PC's and Macs.
An optical computer mouse uses a lightemitting diode to detect movement relative
to a surface, unlike a mechanical
mouse which has a ball which rotates
Digital Pad
Take Notes
Connect to the Pc
Organize Your Notes
4. Send via e-Mail
Input Devices
 Personal computer input devices
 Keyboard
 Mouse
 Speech-recognition technology
 Input devices that recognize human speech
 e.g. automate account identification process
 Digital cameras
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Input Devices (continued)
 Scanning devices
 Optical data readers
 Special scanner
 OMR – Optical mark recognition
(also called optical mark reading and OMR) is the process of capturing
human-marked data from document forms such as surveys and tests.
 OCR – convert handwritten to typed doc into digital data
 Magnetic stripe card
 Swipe card
 Point-of-sale (POS) devices
 Used in retail operations to enter sales
information
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Principles of Information Systems,
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Output Devices
 Display monitors
 Liquid crystal displays (LCDs)
 Printers and plotters
 Digital audio player
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Principles of Information Systems,
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PRINTERS
A device that prints text or graphics on paper. Printers
are connect with computers through “Printer Cable” or
“Printer USB Cable”.
In a network mode, printers have a LAN Port. There are
many different types of printers.
In terms of the technology utilized, printers fall into the
following categories:
Dot matrix Printers
A type of impact printer that produces characters and graphics
by striking pins against an ink ribbon to print closely spaced
dots in the appropriate shape.
Dot-matrix printers are relatively expensive and do not
produce high-quality output.
However, they can print to multi-page forms (that is, carbon
copies), something laser and ink-jet printers cannot do. But
Dot matrix printers make a lot of noise.
Ink: Dot Matrix Printer use ribbon for ink
Ink-jet Printers
A type of printer that works by spraying ionized ink at a
sheet of paper. A typical ink-jet printer provides a
resolution of 600 dots per inch, although some newer
models offer higher resolutions.
In general, the price of ink-jet printers is lower than that of laser printers.
However, they are also considerably slower. Another drawback of ink-jet printers
is that they require a special type of ink.
Ink: Ink-Jet Printers use Ink Cartridges
Laser Printers
A type of printer that utilizes a laser beam to produce an
image on a drum. The light of the laser alters the
electrical charge on the drum wherever it hits. The drum
is then rolled through a tank of toner, which is picked up
by the charged portions of the drum. Finally, the toner is
transferred to the paper through a combination of heat
and pressure. This is also the way copy machines work.
Ink: Laser Printers use Toner Cartridges
Multiple function printers
 Printer, copier, Fax Machine and Scanner
PLOTTERS
 The plotter is a computer printer for printing graphics.
Plotters are different from printers. Plotters draw lines
using pen. As result they can produce continuous lines.
Plotters are expensive than printers. Pen plotters print
by moving a PEN or other instrument across the
surface of a piece of paper. Plotters offered the fastest
way to efficiently produce very large drawings or color
high-resolution ARTWROK.
Computer-based navigation systems
 Computer-based navigation systems
 GPSs (Global positioning system), satellite
based radio navigating system
 Guide to specific destination
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Liquid-crystal display
Light-emitting diode
organic light-emitting diode
Plasma display
CRT -MONITORS
 Some computer monitors generate output with the help
of cathode ray tubes. This type of device is called the
CRT (or, cathode ray tube) monitor.
 However, CRT monitors can be bulky and take up a lot
of desk real estate, be very heavy to carry, and they
require a lot of power to run properly.
 Moreover, the picture screen can distort, display a
"flicker effect," or burn out over time.
LCD and Plasma Monitors
 The newer types of display units are liquid crystal display monitors (or,
the LCD monitor) and plasma screen monitors. LCD and plasma screen
styles are much lighter than their older CRT counterparts.
 LCD models in particular require less power to run. However, these
newer models can be more expensive than traditional computer
monitors.
 LCD (Liquid Crystal Display) computer monitors save a lot of space
and can even be mounted on walls. They provide a wide viewing angle
and come in sizes typically ranging from 17-inches to 60-inches.
OLED-Monitors
OLED (Organic Light Emitting Display) computer
monitors are much thinner and brighter than LCD or
Plasma screens. OLED monitors can also be placed on
transparent surfaces, such as glass, allowing the user to
see through them when not active.
Touchscreen - Monitors
 Touchscreen computer monitors provide a new way of
interacting with your computer with a touch-sensitive
screen. This allows users to interact directly with the
application on screen without need for a mouse or
keyboard.
 Touch computers play a prominent role in the design
of digital appliances such as the personal digital
assistant (PDA), satellite navigation devices, mobile
phones, and video games.
Other Output Devices
 Secondary Storage Devices
 Hard Disk
 CD/DVD
 Pen Drive
 Camera
 Fax Machine
 Speakers
 Headphone
 Projector