1. Chapter 4:
Input and Output

2. Learning Objectives
Explain the purpose of a computer keyboard and the types of keyboards widely used today.
List several different pointing devices and describe their functions.
Describe the purposes of scanners and readers and list some types of scanners and readers in use today.
Understand how digital cameras differ from conventional cameras.
Explain how audio input is accomplished.
Describe the characteristics of a display device and explain some of the technologies used to display images.
List several types of printers and explain their function.
Understand which hardware devices are used for audio output.

3. Overview This chapter covers:
Different types of keyboards and pointing devices
Types of scanners, readers, and digital cameras and what they are used for
Audio input devices
Types of display devices and how they work
Types of printers and how they work
Audio output

4. Keyboards
Keyboard: An input device containing keys, arranged in a typewriter configuration, used to input letters, numbers, and other symbols
Can be wired or wireless
Most PCs today are designed to be used with a keyboard
Contains
Standard alphanumeric keys
Numeric keypad
Function keys
Directional keys and special keys

5. Keyboards 5

6. Keyboards Keyboards are increasingly including alternate input tools
Touch pads
Scroll wheels
Some also include built-in display screens
Portable PCs and mobile devices often use:
Thumbpad
Slide-out keyboard
Pen or touch input
Portable keyboard
Virtual keyboard is an emerging possibility

7. Keyboards

8. Pointing Devices
Pointing device: An input device that moves an onscreen pointer (arrow or insertion point) to allow the user to select objects on the screen
Usually buttons on the device are used to select objects
Common types of pointing devices:
Mouse
Electronic pen
Touch screen

9. The Mouse
Mouse: A pointing device the user slides along a flat surface to move a pointer around the screen and clicks its buttons to make selections
Older mechanical mice use a ball
Newer optical or laser mice track movements with light
Can be wireless

10. The Electronic Pen and Stylus
Electronic pen: Device used to select objects, as well as to draw or write electronically on the screen
Also called tablet pen, digital pen, stylus
Commonly used with pen-based PCs
Used to issue commands and input data
If handwriting recognition is used, written text can be converted to editable typed text

11. Handwriting Recognition

12. The Electronic Pen and Stylus
Also used with:
Digital writing systems
Graphics tablets
Signature capture devices

13. Touch Screens
Touch screen: Display device that is touched with the finger to issue commands or otherwise generate input to the connected PC
Used with:
Desktop and portable PCs
Mobile phones and mobile devices
Interactive whiteboards
Consumer kiosks

14. Touch Screens

15. Other Pointing Devices
Joysticks, gamepads, and other gaming devices
Trackballs
Control buttons and wheels
Touch pads

16. Scanners, Readers, and Digital Cameras
Source documents: Documents containing data that already exists in physical form (order form, photograph, invoice, check, or price label)
Source data automation: Capturing data directly from a source document
Saves time
Increases accuracy

17. Scanners
Scanner (optical scanner): Input device that reads printed text and graphics and transfers them to a computer in digital form
Can scan photos, documents, drawings, (flat objects)
Data is typically input as a single image
If optical character recognition (OCR) is used, text is input as editable, typed text
Types of scanners
Flatbed
Drum
Handheld 3D

18. Scanners Optical resolution: Quality of scanned images
Measured in number of dots per inch (dpi)
Can often be specified when image is scanned
Can be changed when scanned image is edited
Varies with scanner used
Pixel: Smallest colorable area in an electronic image

19. Barcode Readers Barcode readers: Input devices that read barcodes
Barcode: Machine-readable code that represents data as a set of bars
Common types
Universal Product Code (UPC)
ISBN
Code 39
POSTNET code
High-capacity color barcode (HCCB)

20. Radio Frequency Identification Readers
Radio frequency identification (RFID): Technology used to store and transmit data located in RFID tags
RFID tag: Contains tiny chips and radio antennas
Attached to objects for identification purposes
Read by RFID readers
Tags only need to be within range of the reader, rather than in the line of sight
Applications
Tracking inventory and assets
Electronic tolls
Electronic payments (Near Field Communication)
Security

21. Radio Frequency Identification Readers

22. Optical Mark Readers (OMRs)
Optical Mark Readers (OMRs): Input data from special forms to score or tally exams, questionnaires, ballots

23. Optical Character Recognition Devices
Optical Character Recognition (OCR): Reads optical characters that are designed to be identifiable by humans as well as OCR devices
Most machines today are designed to read several standard OCR fonts
Used to process turnaround documents like monthly bills

24. Magnetic Ink Character Recognition (MICR) Readers
Magnetic ink character recognition (MICR) readers: Read MICR characters
Used primarily for banking
MICR readers read the special magnetic characters and sort/process checks

25. Biometric Readers
Biometric data: Based on unique physiological characteristics or personal trait
Fingerprint
Hand or face geometry
Iris of the eye
Voice or signature
Biometric readers: Used to input biometric data
Can be stand-alone or built into another piece of hardware (keyboard, mouse)
Also being built into computers and storage devices to allow access only by authorized individuals
Most often used for access control and to verify transactions

26. Biometric Readers

27. Digital Cameras
Digital cameras: Record images on digital storage medium rather than film
Can either be still cameras or video cameras
Typically use flash memory for storage
Images can be edited, posted to a Web page, burned to a CD or DVD disc, etc.
Digital still cameras
Available in a wide variety of sizes and capabilities
Photos can be transferred to a PC or printer
Camera quality is measured in megapixels
Digital video cameras
Digital camcorders
PC video cameras (PC cams, Web cam)

28. Digital Cameras

29. Audio Input
Audio input: The process of entering audio data into the computer
Voice (narrations, podcasts, etc.)
Music (from CDs, MIDI keyboards, etc.)
Voice input systems (speech recognition systems)
Enable a computer to recognize the human voice
Consist of a microphone or headset and appropriate software
Can be used to dictate text or commands into a PC

30. Voice Input Systems

31. Display Devices Display device: Presents output visually
Monitor: Display device for a desktop PC
Display screen: Screen built into a variety of devices
Notebook and handheld PCs,
Mobile phones and mobile devices
E-books readers, digital photo frames, and other consumer devices, and many other devices
Digital signage systems
E-paper

32. Display Devices

33. Display Device Characteristics
Color vs. monochrome displays
CRT vs. flat-panel display
Size
Screen resolution
Wired vs. wireless
2D vs. 3D
Digital TV and HDTV capabilities
Touch screen capabilities
Video card being used determines some of the characteristics (bit depth, video RAM, connections, etc.)

34. Screen Resolution

35. Flat-Panel Display Technologies
Liquid crystal displays (LCDs): Use charged liquid crystals between sheets of glass or plastic
Requires backlighting
LED (Light emitting diode): Used in displays as well as a variety of consumer products

36. Flat-Panel Display Technologies
Organic light emitting diode (OLED) displays: Use emissive organic material to display brighter and sharper images
Do not need backlighting
Used with consumer devices (portable digital media players, TVs, etc.)

37. Flat-Panel Display Technologies
Special types of OLEDs
Flexible OLEDs (FOLEDs)
Transparent OLEDs (TOLEDs)
Phosphorescent OLEDs (PHOLEDs)
Interferometric Modulator Displays (IMOD): Essentially a complex mirror that uses external light to display images
Designed initially for mobile phones and portable devices
Images are bright and clear, even in sunlight
Plasma displays: Use layers of gas to display images
Most often used on large displays

38. Flat-Panel Display Technologies

39. Data and Multimedia Projectors
Data projector: Display device that projects all computer output to a wall or projection screen
Most data projectors today can project video, in addition to computer output
Can be wireless or integrated into devices
FogScreen systems projects on a thin layer of fog
Holographic projectors are in development

40. Printers Printers: Produce hard copy Printer Characteristics
Printing technology used
Impact vs. nonimpact
Color vs. black and white
Personal vs. network printers
Print resolution
Print speed
Possible connections
Multifunction capabilities

41. Printers

42. Laser Printers
Laser printer: Uses toner powder and technology similar to that of a photocopier to produce images on paper
The standard for business documents
Print one entire page at a time
Generally faster and have better quality than ink-jet printers
Can be black and white or color
Common print resolution for laser printers is between 600 and 2,400 dpi
Use toner cartridges

43. Laser Printers

44. Ink-Jet Printers
Ink-jet printer: Sprays droplets of ink to produce images on paper
Usually 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
Use ink-jet cartridges
Newer printers with full width printheads are much faster
Potential applications for the future
Dispensing liquid metal, aromas, computer chips and other circuitry, “printing” human tissue

45. Ink-Jet Printers

46. Special-Purpose Printers
Photo printers
Barcode, label, and postage printers
Portable printers
Plotters and wide-format ink-jet printers
3-D printers

47. Audio Output Audio output: Output in the form of voice or music
Speakers
Voice output systems
Headphones and headsets
Earphones and earbuds

48. Summary Keyboards Pointing Devices
Scanners, Readers, and Digital Cameras
Audio Input
Display Devices
Printers
Audio Output