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Chapter 5

Input and Output: The User Connection

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Input vs. Output

Users use input devices to provide data to the computer

Output devices provide information to the user

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Input devices

Keyboard Function keys Main keyboard

Shift, control, Caps lock, tab Numeric keys and status lights

Num lock Num lock, Insert, and Caps lock are

“toggle” keys

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Input Devices–Pointing Device

Pointer Arrow

Insertion point or cursor Vertical bar

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Input Devices–Pointing Device

Mouse Mechanical mouse Optical mouse Wireless mouse

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Input Devices–Pointing Device Trackball

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Input Devices–Pointing Device Touchpad

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Input Devices–Pointing Device Pointing stick

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Input Devices–Pointing Device Joystick

Used often for games

Can be used instead of a mouse

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Input Devices–Pointing Device Graphics tablet

Stylus Puck

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Input Devices–Pointing Device

Touch screens Used in kiosks, a

self-contained station

Kiosks are found in libraries, museums, airports, and shopping malls

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Input Devices–Pointing Device Pen-based

computing

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Magnetic-Ink Character Recognition (MICR)

A type of source data automation

Used most by the banking industry

MICR numbers printed on checks

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SCANNERS Use laser light 3 types

Flatbed scanner Sheetfed scanner Handheld scanner

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SCANNERS (Extra)

Flatbed scanner Scans one sheet at a time Can be used on books Can scan 3-D objects Take a lot of desk space

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SCANNERS (Extra)

Sheetfed scanner Scans one sheet at a time Cannot scan bound material Take less space than flatbed

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SCANNERS (Extra)

Handheld scanner Least expensive Least accurate May require several passes to get a

complete page scanned in

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Optical Recognition

Optical Mark Recognition (OMR) For “reading” marks, lines, filled circles,

etc Optical Character Recognition (OCR)

Analyzes an image, converts it into characters

Can recognize handwritten characters if done in block printing

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Optical Recognition

Bar codes Universal Product Code (UPC) is one

standard Other codes exist

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Voice Input

Speech recognition Speaker-dependent

“trained” for a specific person’s voice Speaker-independent

Recognize any voice Limited vocabulary

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Input Device Digital camera

No film Uses memory

chips, disks, or memory sticks

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Output Devices CRT monitor

Cathode Ray Tube Raster scanning 3 colors of light:

red, green, and blue produce all the colors

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Output Devices

CRT monitor quality Refresh rate (scan rate) = number of Interlaced vs. non-interlaced Resolution

More pixels means higher resolution Dot pitch Size of monitor

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Output Devices Flat Panel screen

Liquid crystal display (LCD)

Active matrix (TFT) Passive matrix

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Computer Output

Monitor Softcopy

Printer Hardcopy Portrait vs. landscape Resolution in dpi (dots per inch)

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Computer Output

Voice output Speech synthesis Synthesis by analysis Synthesis by rule

Music and sound output MIDI

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Computer Output

Graphics cards – provide output to a monitor

Have memory chips on the card Graphics standards

SVGA - Super Video Graphics Array XGA – Extended Graphics Array

XGA supports more simultaneous colors than SVGA

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Output Devices

Dot-matrix printer Impact Pins striking a ribbon against paper Used for multiple part forms

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Output devices

Laser printer Non-impact Light beam helps transfer images to

paper High quality Uses toner and technology similar to

a photocopier

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Output Devices

Ink-jet printer Non-impact Spray ink onto paper Good quality Most can print in color

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Computer Terminal

Dumb terminal Keyboard and monitor No processing capability

Intelligent terminal Keyboard, monitor, memory Some processing capability

Both dumb and intelligent terminals must be connected to a “host” or server computer

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Point-of-sale terminal (POS)

Specialized input and output devices The “cash register” at a supermarket

is a POS Input through keyboard, scale, plus

one or more scanners Output to one or more display devices

plus receipt printer