Chapter 5
Input and Output
Input and Output


Input devices convert data from the user into a form understood by the computer.
Output devices convert the processed 0s and 1s into a form that the user can
understand.
 Hard copy—permanently recorded, such as on paper.
 Soft copy—temporarily recorded, such as on a computer screen.
Keyboards





Computers usually use a keyboard for text-based input.
Keyboards can differ in number of keys, key arrangement, types of special keys, and
touch.
Function keys enable software packages to be customized to meet a user's
applications needs.
The numeric keypad makes it easy to enter numbers quickly.
Portable keyboards and thumb pads are increasingly being used with portable PCs
and mobile devices.
Pointing Devices


Mice
 The mouse is the most common type of pointing device.
 Can be mechanical or optical.
 Used to select onscreen objects, issue commands, move objects, scroll through
documents, etc.
Electronic pens (light pen, stylus)




An alternative to the mouse to select objects or to write or draw on the screen.
Commonly used with:
 Graphics tablets
 Digital portfolios and digital pens
 Signature capture devices
 Pen-based computers
 Handwriting recognition technology
Touch screens
 Used when other input devices are impractical.
 Often used when consumer input is required, as in consumer kiosks.
Other common pointing devices
 Joysticks and other gaming devices
 Trackballs
 Pointing sticks
 Touch pads
Scanners and Related Devices


Source data automation involves converting source documents to digital form or
initially collecting data in digital form.
Often involves scanning or reading devices.
Scanners



Scanners (optical scanners) convert hard-copy images of text pages, photographs, and
drawings into digital form.
Types of scanners:
 Flatbed
 Sheet-fed
 Handheld
 Drum
 Three-dimensional
Quality of scanned images are measured by resolution.
Optical Mark Readers (OMRs)

Read optical marks, such as on:
 Exams
 Census forms
 Voting ballots
 Lottery forms
Bar-Code Readers



Bar code—an optical code consisting of several bars of varying widths that form a
unique, identifiable code.
Read by fixed or portable bar-code readers.
Common types:
 Universal Product Code (UPC)
 POSTNET code
 Proprietary codes for shippers, hospitals, and other businesses
Optical Character Recognition (OCR) Devices


Optical characters are designed to be identifiable by humans as well as OCR device.
Widely used in turnaround documents, such as monthly bills.
Magnetic Ink Character Recognition (MICR) Readers

MICR readers can read the special magnetic characters and sort and process
documents accordingly.
Biometric Input Devices




Used to input biometric data about a person.
Biometric data is based on unique physical characteristics (e.g. fingerprint) or
personal traits (e.g. voice).
Used for access and to verify transactions.
Biometric readers can be stand-alone or built into keyboards or other hardware
devices.
Multimedia Input Devices


Digital cameras record data onto digital media instead of conventional film or tape.
Images can be transferred to a PC via a cable or the storage media (such as a flash
memory card with a digital still camera).

Can be digital still cameras or digital video cameras.

Digital still cameras





Images are usually stored on flash memory cards.
Photos can usually be immediately previewed and deleted, if needed.
Photos are easily transferred to a PC to be stored and/or printed.
Camera quality is measured in mexapixels.
Digital photos can be printed at home or at a photo lab.
Digital video cameras




Store images on digital media (typically digital tape or optical discs).
Video can be easily transferred to a PC for editing and/or burning onto a DVD.
Can be used for videoconferencing and Web cams.
Audio input devices




Voice-input systems convert spoken words to digital data.
Voice input can be used to input data or commands into a PC as well as for telephony.
Music-input systems can input and record music (either original compositions or via a CD
or DVD player).
Display Devices
Display device characteristics
 Color vs. monochrome displays
 Size (measured diagonally)
 Screen resolution
 Graphic standards
 CRT (cathode-ray tube) monitors—display images similar to conventional
televisions.
 Quality is measured in dot pitch.
 Flat-panel displays—form images by manipulating electronically-charged
chemicals or gases between thin panes or glass or plastic.
 Common types:
 Liquid crystal displays (LCD)
 Gas plasma
 Used for monitors, televisions, handheld devices, and other consumer products.
Smart displays
HDTV monitors
Data projectors
Emerging display technologies and applications (e.g. flexible displays, e-paper,
integrated displays, etc.)





Printers
Printer characteristics






Printer resolution—measured in dots per inch (dpi)
Impact vs. non-impact printing
Color vs. black and white
Personal vs. network printers
Speed
Laser Printers

Work on the technology as xerography
Ink-Jet Printers





Print with tiny drops of liquid ink.
Typically print in color.
Often the choice for home use.
Print fairly slowly, one line at a time.
Quality not quite as good as a laser printer.
Special Purpose Printers




Photo printers
Bar-code printers
Label printers
Portable printers
Multimedia Output Devices


Speakers
Voice-output systems
Key Terms
Bar code
Bar-code printer
Bar-code reader
CRT (cathode-ray tube)
monitor
Data projector
Digital camera
Display device
Dots per inch
Electronic pen
Ergonomic keyboard
Flatbed scanner
Flat-panel display
Function key
Graphics tablet
Handheld scanner
Handwriting
recognition
Hard copy
Impact printer
Ink-jet printer
Input device
Joystick
Keyboard
Laser printer
LCD
MICR
MIDI
Monitor
Monochrome
Mouse
Optical character
recognition (OCR)
Output device
Photo printer
Pixel
Plotter
Pointing device
Pointing stick
POS
Printer
QWERTY
Scanner
Smart display
Softcopy
Source data automation
Speakers
Stylus
Touch pad
Touch screen
Trackball
Voice-input system
Voice-output system