1. Computer Fundamentals
Input/Output Devices

2. What You Will Learn About
The purpose of special keys and the most frequently used pointing devices
Input devices used to get audio and digital data into the computer
The characteristics of a monitor’s quality and the various types of monitors
The two major types of printers
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3. Input Input is any data entered into the computer’s memory.
Types of input include:
Data – Unorganized information (words, numbers, images, or sounds) that the computer converts to meaningful information
Software – Programs transferred from storage devices to the computer’s memory
Commands – Instructions that tell the computer what to do
Responses – Prompts requiring user feedback
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4. Input Devices: Giving Commands
Keyboard
Mouse
Other Pointing Devices
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5. Audio Input Computers can accept input from a microphone.
An expansion card called a sound card records and plays back sound files.
Sound files contain digitized sound data.
Popular sound file formats include:
Windows WAV
Moving Pictures Expert Group (MPEG)
MP2 and MP3
Musical Instrument Digital Interface (MIDI)
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6. Audio Input: Speech Recognition
Speech recognition is a type of input in which the computer recognizes words spoken into a microphone.
Special software and a microphone are required.
Latest technology uses continuous speech recognition where the user does not have to pause between words.
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7. Digital Input: Digital Cameras and Digital Video
Click on the picture to play the video.
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8. Alternative Input Devices
Fax Machines
Scanners
Flatbed
Barcode reader
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9. Output Devices: Engaging our Senses
Output devices are peripheral devices that enable us to view or hear the computer’s processed data.
Visual output – Text, graphics, and video
Audio output – Sounds, music, and synthesized speech
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10. Monitors
CRT
LCD
A monitor is a peripheral device which displays computer output on a screen.
Screen output is referred to as soft copy.
Types of monitors:
Cathode-ray tube (CRT)
Liquid Crystal Display (LCD or flat-panel)
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11. Monitor Specifications
Screen size – The diagonal measurement of the screen surface in inches (15, 17, 19, 21)
Resolution – The sharpness of the image determined by the number of horizontal and vertical dots (pixels) that the screen can display (800 x 600, 1024 x 768, 1600 x 1200)
Refresh rate – The speed at which the screen is redrawn (refreshed) and measured in Hertz (Hz) (60Hz, 75Hz)
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12. Printers
A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output.
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13. Types of Printers
Laser
Inkjet
Inkjet printer, also called a bubble-jet, makes characters by inserting dots of ink onto paper
Letter-quality printouts
Cost of printer is inexpensive but ink is costly
Laser printer works like a copier
Quality determined by dots per inch (dpi) produced
Color printers available
Expensive initial costs but cheaper to operate per page
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14. Plotter
A plotter is a printer that uses a pen that moves over a large revolving sheet of paper.
It is used in engineering, drafting, map making, and seismology.
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15. Audio Output: Sound Cards and Speakers
Audio output is the ability of the computer to output sound.
Two components are needed:
Sound card – Plays contents of digitized recordings
Speakers – Attach to sound card
Click an icon to play music.
Click the icon again to stop playing.
Try clicking on Cheers while playing music.
WMA
MIDI
MP3
WAV
Beethoven 1:15 min
Rocky 2:56 min
Hornsby 48 sec
Cheers 15 sec
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