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C OMPUTING. E SSENTIALS. 1999. 2000. 1999. 2000. Timothy J. O’Leary Linda I. O’Leary. 1999. Presentations by: Fred Bounds. 2000. Input and Output. 4. CHAPTER. Competencies. After reading this chapter, you should be able to:
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COMPUTING ESSENTIALS 1999 2000 1999 2000 Timothy J. O’Leary Linda I. O’Leary 1999 Presentations by:Fred Bounds 2000
Input and Output 4 CHAPTER
Competencies After reading this chapter, you should be able to: 1. Explain the difference between keyboards and direct-entry input devices. 2. Describe the features of keyboards and the four types of terminals. 3. Describe direct-entry devices used with microcomputers. Computing Essentials 1999 - 2000 Chapter Four
Competencies 4. Discuss voice recognition systems. 5. Describe monitors and monitor standards. 6. Describe printers (ink-jet, laser, thermal) and plotters (pen, ink-jet, electrostatic and direct-image) 7. Describe voice-output devices. Computing Essentials 1999 - 2000 Chapter Four
Overview • Two most important places for computer- human interface • Computers can only work with binary language • Input devices translate what we understand to a form acceptable to the computer • Output devices do the reverse Computing Essentials 1999 - 2000 Chapter Four
Input: Keyboard versus Direct Entry Input devices convert people-readable data into machine-readable form. Input may be by keyboard or direct entry.
Data Entry • Keyboard entry • Keys like typewriter to enter text and numbers • Data normally comes from an original or source document • Direct entry • Data in machine readable form at entry point Computing Essentials 1999 - 2000 Chapter Four
Data Entry • Entry methods • Point-of-sale (POS) methods - keyboard and bar scanning • Wand reader • Platform scanner A Point-of-sale transaction Computing Essentials 1999 - 2000 Chapter Four
Keyboard Entry In keyboard entry, people type input. There are four types of terminals: dumb, intelligent, network computer and Internet terminal.
Windows key Traditional keyboard Numeric keypad Function keys Escape key Spacebar Navigation keys Computing Essentials 1999 - 2000 Chapter Four
Keyboard Entry • Keyboards - besides alphanumeric, special purpose keys that toggle or work with the Control, Alt and Shift keys Computing Essentials 1999 - 2000 Chapter Four
Keyboard Entry • Terminals - input and output device connecting users to mainframe computers • Dumb terminal - no processor or local storage • Intelligent terminal - CPU, memory and storage; Net PC, or network computer Computing Essentials 1999 - 2000 Chapter Four
Keyboard Entry • Terminals - input and output device connecting users to mainframe computers • Network terminal - low cost alternative to intelligent terminal • Internet terminal - or Web terminal, accesses and displays Web pages on a television set Computing Essentials 1999 - 2000 Chapter Four
Direct Entry Direct entry creates machine-readable data that can go directly to the CPU. Direct entry includes pointing, scanning and voice-input devices.
Direct Entry • Data is already in machine-readable format • No keyboard or transcription device required • Three categories • Pointing devices • Scanning devices • Voice-input devices Computing Essentials 1999 - 2000 Chapter Four
Traditional keyboard Cable Retaining ring Roller ball Pointing Devices • Mouse, trackball or touch-surface - cursor moves in response to rolling ball or moving finger Left button Right button Computing Essentials 1999 - 2000 Chapter Four
Pointing Devices • Mouse, trackball or touch-surface - cursor moves in response to rolling ball or moving finger • Touch screen - screen recognizes position of touching finger Computing Essentials 1999 - 2000 Chapter Four
Pointing Devices • Mouse, trackball or touch-surface - cursor moves in response to rolling ball or moving finger • Touch screen - screen recognizes position of touching finger • Light pen - screen recognizes position of light-sensitive pen-like device Computing Essentials 1999 - 2000 Chapter Four
Pointing Devices • Digitizer - special pad and stylus used to capture images hand drawn • Digital camera - image recorded digitally and stored on chips or disks; not yet film quality, but increasingly popular as prices drop • Digital notebook - notepad that can capture handwriting and store it Computing Essentials 1999 - 2000 Chapter Four
Digitizer: an industrial design Computing Essentials 1999 - 2000 Chapter Four
Pen-based computer: recording inventory Computing Essentials 1999 - 2000 Chapter Four
Scanning Devices • Image scanner - images scanned and broken into digital code • Fax machine - scanner codes images and sends them over the phone line • Bar-code readers - photoelectric scanner reads vertical bars Computing Essentials 1999 - 2000 Chapter Four
Image Scanner • Identifies images on a page and converts them to digital electronic signals • Increased usage in desktop publishing and for home use as well Computing Essentials 1999 - 2000 Chapter Four
Fax Machines • Fax machine - scans images and transmits them over phone lines to a receiving fax on the other end • Fax modem cards in computers achieve same results without scanning capability Computing Essentials 1999 - 2000 Chapter Four
Bar-Code Readers • Photoelectric scanners that read vertical zebra-striped marks called bar codes • The bar code is a unique identifier that links to a product code in the store’s computer Computing Essentials 1999 - 2000 Chapter Four
Bar-Code Readers • The computer contains the product description and price Computing Essentials 1999 - 2000 Chapter Four
Scanning Devices • Character and mark recognition devices • Magnetic-ink character recognition (MICR) - used by banks to read magnetically encoded characters • Optical-character recognition (OCR) - specially preprinted characters are read by OCR devices such as wand scanners • Optical-mark recognition (OMR) - devices sense the presence or absence of marks, common for test scoring Computing Essentials 1999 - 2000 Chapter Four
Voice-Input Devices • Convert speech into digital code • Most common device is the microphone • Voice recognition systems • Microphone, bundled with sound card and software • Some voice recognition systems must be trained for user’s voice • Some can translate from one language to another Computing Essentials 1999 - 2000 Chapter Four
Voice Recognition Systems • Continuous speech - used to issue commands to special application programs • Discrete-word - permits users to dictate directly into a microcomputer Computing Essentials 1999 - 2000 Chapter Four
Output: Monitors, Printers, Plotters, Voice Output devices convert machine-readable information into people-readable form.
Monitors Monitor standards indicate screen quality. Some monitors are used on the desktop, others are portable.
Monitor Standards • VGA (“Video Graphics Array”) - 16 colors at 640 by 480 • Super VGA or SVGA (“Super Video Graphics Array”) - minimum resolution of 800 by 600, up to 1600 by 1200 • XGA (“Extended Graphic Array”) - resolution up 1024 by 768, over 18 million colors Computing Essentials 1999 - 2000 Chapter Four
Serial mouse, modem, keyboard Video monitor Cables Computing Essentials 1999 - 2000 Chapter Four
Color and Resolution Capabilities VGA 640 X 480 16 XGA 1024 X 768 65,536 Computing Essentials 1999 - 2000 Chapter Four
Monitors • Cathode-Ray Tubes - similar to television technology • Flat-Panel Monitors - or liquid display (LCD) monitors • Passive-matrix or dual-scan - images created by scanning the entire screen • Active-matrix - each pixel is individually activated Computing Essentials 1999 - 2000 Chapter Four
A desktop monitor: SVGA display Computing Essentials 1999 - 2000 Chapter Four
Printers There are three types of printers: ink-jet, laser and thermal.
Printers • Ink-jet Printer • Sprays droplets of ink on paper to produce text and images • Inexpensive Computing Essentials 1999 - 2000 Chapter Four
Printers • Laser Printer • Technology similar to photocopier • Laser beam creates images which are applied via toner to paper Computing Essentials 1999 - 2000 Chapter Four
Printers • Thermal Printer • Heat used to produce text and images on heat-sensitive paper • Very high quality color option Computing Essentials 1999 - 2000 Chapter Four
Printers • Other Printers • Dot-matrix uses pins to produce dots on paper to represent text and images • Chain printer - high speed printer for minicomputers and mainframes Computing Essentials 1999 - 2000 Chapter Four
Plotters Plotters are special-purpose drawing devices.
Plotters • Pen Plotter • Moving pen or pencil over drafting paper • Least expensive • Slower speed and limited capability • Ink-Jet Plotter • Uses sprayed droplets of ink • Faster Computing Essentials 1999 - 2000 Chapter Four
Plotters • Ink-Jet Plotter • Uses sprayed droplets of ink • Faster • High quality • Quiet operation Computing Essentials 1999 - 2000 Chapter Four
Plotters • Electrostatic Plotter • Electrostatic charges (rather than pens) produce dots on specially treated paper • Paper is then developed • Very fast • Hazardous chemicals Computing Essentials 1999 - 2000 Chapter Four
Plotters • Direct Imaging Plotter • Electrically heated pins create images on heat-sensitive paper • Expensive paper required • Two-color output only Computing Essentials 1999 - 2000 Chapter Four
Voice-Output Devices Voice-output devices vocalize prerecorded sounds.
Voice-Output Devices • Make sounds that resemble human speech but actually are using prerecorded vocalized sounds • Components are often a sound card and a speaker system Computing Essentials 1999 - 2000 Chapter Four