computing

ESSENTIALS
5
Input and
Output
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing

ESSENTIALS
Competencies
Input devices
Digitizing
Output devices
Multifunctional devices
Telephony
Terminals
Copyright 2003 The McGraw-Hill Companies,
Inc.
2
computing
ESSENTIALS

Input


Data or instructions

Directly from user

From other sources
Input device

Hardware to provide input to computer
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing

ESSENTIALS
Input Devices

Keyboards

Pointing devices

Scanners

Image capture
devices

Audio capture
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Keyboards

Most common input device

Characters, numbers, symbols converted to
electrical signal

Typewriter keyboard, numeric keypad, special
keys

Navigation keys

Function keys

Windows key
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Keyboards


Toggle keys

Turns a feature on or off

Caps Lock
Combination keys

Held down in combination with another key

Control key, Alt key
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Inc.
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computing
ESSENTIALS

Pointing Devices



Control a pointer on
the monitor
Used to select
buttons, menus, links
Mouse
 Most common
pointing device
 Mechanical
 Optical
 Wireless
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Pointing Devices



Trackball
 Move roller ball with thumb
Touch surface
 Move finger across surface of pad
 Tap to select
Pointing stick
 Middle of keyboard
 Move with finger
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Pointing Devices


Joystick
 Popular for computer games
 User grips stick to maneuver
Touch screen
 Special monitor
 Screen layer with crisscrossed beams of
infrared light
 Select by touching screen directly
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Scanning Devices

Copy data from a source

Types of scanners

Optical scanner

Bar code readers

Character and Mark recognition
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Optical Scanners



Copy text or images
Can be displayed, printed, or stored
Types of optical scanners
 Flatbed scanner
 Source placed on glass surface
 Image scanned from below
 Portable scanner
 Handheld device that slides across
source
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Bar Code Readers



Photoelectric scanner
Read bar codes
 Alternating black & white vertical bars
 Universal Product Code (UPC)
Seen in grocery stores, retail stores
Copyright 2003 The McGraw-Hill Companies,
Inc.
12
computing
ESSENTIALS

Character & Mark Recognition

Magnetic-ink character recognition (MICR)


Reads magnetically encoded characters
Optical-character recognition (OCR)

Reflects light off special preprinted
characters

Optical-mark recognition (OMR)

Senses presence or absence of marks
Copyright 2003 The McGraw-Hill Companies,
Inc.
13
computing
ESSENTIALS

Image Capturing Devices




Create or capture original images
Digital camera
 Image recorded digitally to memory
Digital video cameras
 Capture motion
Webcams
 Capture images for broadcast on Internet
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Digitizing Devices



Capture sketches, maps, drawings
Flat surface, writing device
Types
 Graphics tablets
 Special

tablet, stylus
Digital notebook
 Regular
paper, pen
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Audio-Input Devices




Convert sound into digital format
Voice recognition system
 Operate computer by voice command
 Dictation
 Microphone, sound card, software
Discrete
Continuous
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Voice Recognition Systems
Types

Recognize individual words based on sound

Discrete-speech recognition


Cannot distinguish same-sound words
Continuous-speech recognition

Can distinguish same-sound words

Evaluates context of words
Copyright 2003 The McGraw-Hill Companies,
Inc.
17
computing
ESSENTIALS

Output

Processed data from a computer

Text, graphics, photos, audio, video

Common output devices

Monitor

Printer

Plotter

Voice
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Monitors

Most frequently used output
device

Size is measured by diagonal
of screen


Common sizes: 15, 17, 19,
21 inches
Clarity is indicated by
resolution

Measured in pixels

More pixels = better clarity
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Monitor Standards

Resolution capabilities indicated by a monitor’s
standard

Super Video Graphics Array (SVGA)

Extended Graphics Array (XGA)

Super Extended Graphics Array (SXGA)

Ultra Extended Graphics Array (UXGA)
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Inc.
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computing
ESSENTIALS

Monitor Types





Cathode-Ray Tubes (CRT)
 Most common
Flat-panel monitors
 Passive-matrix
 Active-matrix
eBook readers
Data projectors
High-definition television (HDTV)
Copyright 2003 The McGraw-Hill Companies,
Inc.
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computing
ESSENTIALS

Printers

Produces hard copy output

Ink-jet printer


Laser printer


Sprays droplets of ink
Laser produced images
Thermal printer

Heated element produce image on heat
sensitive paper
Copyright 2003 The McGraw-Hill Companies,
Inc.
22
computing
ESSENTIALS

Other Printers



Dot-matrix
 Series of pins on print head
 Inexpensive, not high quality
Chain printer
 Used on networks
Plotter
 Maps, architectural drawings
 High quality, larger sized output
Copyright 2003 The McGraw-Hill Companies,
Inc.
23
computing
ESSENTIALS

Audio Output Devices

Translate computer data into understandable
sounds


MP3 files
Components

Sound card

Speaker system or headphones
Copyright 2003 The McGraw-Hill Companies,
Inc.
24
computing
ESSENTIALS

Combination Input/Output
Devices





Devices are combined into one device
 Save room
 Specialized applications
Fax machine
Multifunctional device
Telephony
Terminals
Copyright 2003 The McGraw-Hill Companies,
Inc.
25
computing
ESSENTIALS

Fax Machine

Facsimile transmission machine

Sends and receives images across telephone
lines

Fax/modem board

Give computer same capability
Copyright 2003 The McGraw-Hill Companies,
Inc.
26
computing
ESSENTIALS

Multifunctional Device




Combines
 Scanner
 Printer
 Fax machine
 Copying machine
Cost effective
Saves space
Popular in small offices or home
Copyright 2003 The McGraw-Hill Companies,
Inc.
27
computing
ESSENTIALS

Telephony

Uses Internet rather than traditional
communication lines

Requires

Internet telephone

Internet

Special service provider
Copyright 2003 The McGraw-Hill Companies,
Inc.
28
computing
ESSENTIALS

Terminals



Devices connected to servers
Input and output
Types
 Dumb terminal
 Intelligent terminal
 Network terminal
 Internet terminal
Copyright 2003 The McGraw-Hill Companies,
Inc.
29
computing
ESSENTIALS

A Look to the Future

Brain-machine interface

Signal interceptor in brain translates into
action on the computer

Restore mobility to paralyzed

Prosthetic limbs

Virtual reality
Copyright 2003 The McGraw-Hill Companies,
Inc.
30