Data Entry Input Devices

1
Input / Output (I/O) Devices

• Data Entry Input Devices
• Keyboard - QWERTY
• function keys
• numeric keypad
• Pointing Devices
• Mouse
• Light pen
• Joystick
• Trackball
• Touchpad (notebooks)
• Touch Screen

2
Input / Output (I/O) Devices

• Data Automation Input Devices
• OCR Optical Character Recognition
• Utility Bills ESB
• Typically use special font e.g. OCR1
• OMR Optical Mark Recognition
• (e.g. lotto tickets)
• Image scanner
• OCR software
• DIP Document Image Processing e.g. for CAO forms
• Bar code Scanner
• Reads an optical code
• Universal Product Code UPC
• (supermarket checkouts/ libraries)
• Often used as key component of Point-of-Sale
  system (POS)

3
Input / Output (I/O) Devices

• Digital Camera
• Voice recognition
• (e.g. Viva Voice by IBM, Dragon)
• Handwriting recognition
• HP Ipaq Palm Pilot
• Smart Cards
• contain a processor e.g. Telecom phonecards
• MICR Magnetic ink character recognition
• Used on bank cheques

4
Output Devices

• Display devices e.g. computer monitor is what
  most people use with PCs.
• A computer terminal is made up of a monitor and a
  keyboard. It is a dumb device unlike a PC.
  Terminals may be used to access a mainframe
  computer.
• Screen size varies from 15 to 27 inches, measured
  diagonally across the screen.
• Resolution
• Images are usually made up of tiny dots called
  pixels (picture elements). The higher the
  resolution , the better the quality of picture.

5
Output Devices

• Resolution may be measured by either
• pixel density e.g. .26 or .28
• (distance between pixels in millimetres)
• or
• as a matrix of pixels e.g. 640 x 480
• 640 x 480 rows VGA standard
• 800 x 600 SVGA standard
• 1024 x 768 XGA standard
• 1080 x 1024 SXGA standard
• 1600 x 1200 UXGA

6
Output Devices

• Colour
• Most monitors are RGB (red-green-blue) i.e. form
  colours by combinations of primary colours.
• Most monitors produce non-interlaced images i.e
  all lines are redrawn when the screen is
  refreshed. TVs produce interlaced images i.e
  every other line is redrawn on every refresh.
• The screen is usually refreshed 60 times a
  second.

7
Output Devices

• Landscape Screen is wider than it is high
• Portrait Screen is higher than it is wide
• CRT versus Flat-Panel
• Desktop monitors are typically CRT (cathode-ray
  tube) devices like TVs, although flat screens are
  becoming more popular as they take up less space
  but are more expensive.
• Notebooks use flat-screens which require less
  power and are lightweight.
• Flat-screens often use LCD (liquid crystal
  display) technology.
• Active-matrix LCDs provide sharper images than
  passive-matrix LCDs but at higher cost.

8
Output Devices Printers

• Variety of Print technologies
• Ink-jet high quality and very popular Usually
  Colour
• Laser (page printer) highest quality
• Colour laser printers are much more expensive
  than blackwhite
• Cost of ink-jet cartridges/colour toner is an
  issue in choosing a printer
• Dot-matrix good quality largely replaced by
  ink-jet
• Line-printers Fast, low quality bulk printing on
  computer paper

9
Output Devices Others

• Plotters for CAD (Computer Aided Design) output
• architectural/engineering drawings
• A3 laser printers now also used for these
  applications
• Speakers
• As in sound systems
• Computer Output on Microfilm (COM)
• e.g. for archival purposes

10
Communications Devices

• Modem Modulator/demodulator
• Uses to allow computers communicate over analog
  telephone lines
• Converts computer digital signals to analog
  signals and vice versa
• Operates at speeds up to 56Kbps
• bps bits per second
• ISDN Card
• Digital communication device requires digital
  phone line
• Operates at speeds from 64Kbps, 128 Kbps (home
  use) to low Megabit range
• Much more reliable than modem
• DSL/ADSL Card
• Similar to ISDN but operates at much higher
  speeds (140Kbps to 3 Mbps)
• Network Card (Ethernet card, LAN card)
• Short Distances (lt1000m)
• used inside an organisation like UCD
• 10Mbps to 100Mpbs to 1000 Mbps

11
Computer System Storage and I/O Devices
12
I/O Devices and Communication Devices Review

• Data entry
• Keyboard, mouse, joystick, light pen, touch pad
  etc
• OCR, OMR, Barcode scanner, DIP, MICR
• Digital Camera, Voice, Smart Cards
• Output
• Monitor (VGA, SVGA, XGA etc)
• CRT, LCD
• Printer
• Inkjet, Laser, Dot-Matrix
• Plotter
• Speakers
• Communication Devices
• Modem
• ISDN
• ADSL/DSL
• Network Card