1. Specialized Input and Output

2. Inputting Sound ● The microphone is the most basic device for inputting sounds into a computer ● Microphones capture sounds in analog form a series of waves or vibrations ● To be usable by a computer, sounds must be in digital form - converted to binary code

3. Sound card 1.Digitizes sound by changing it from analog to digital 2.Processes digital sound 3.Sometimes the sound card reduces the size of sound files by compressing the data 4.Finally the sound card reverses the digitizing process so you can play analog sounds through the speakers

4. Inputting Images ● Facsimile (fax) machines ● Scans printed documents and sends them over phone lines ● Many home printers now include a fax machine

5. Digital Cameras ● Computer chips takes the information from the lens and records it as pixels or small dots that form the image ● Has memory to store the pictures you take ● Some digital cameras have memory cards ● Many digital cameras can connect to the computer via a cable or wireless link

6. Scanners ● Photos, drawings, handwritten material, text can all be digitized by a scanner ● Uses optical character recognition software ● Four types of scanners: flatbed, sheetfed and handheld

7. Inputting Video ● Digital video cameras record moving images in digital form ● A video capture card converts analog videos to digital format ● These cards can also compress files so they occupy less storage space

8. Specialized Output Devices ● The images you see on your monitor are created by video adapters ● Electric currents are sent from the video adapter to the monitor ● The amount of current sent by the video adapter determines the color ● the video adapter processes data so the CPU can take care of other jobs ● It also has its own memory called video memory or VRAM to free up space in the computer’s memory

9. Outputting Images with Printers ● Inkjet and laser printers have much higher quality and are most often used for printing graphic images. ● Thermal transfer printers are best for printing color images. They use heat to transfer colored dyes onto paper. They only work with glossy paper.

10. Outputting Video ● Data projectors show the video on a screen and it can be viewed by many people ● Some devices let you send video from a computer to a HDTV screen ● Headsets with two LCD panels can be worn giving 3-D space effect ● CAVE (Cave Automated Virtual Environment) a room in which 3-D images are shown on floor walls and ceiling. Person wears glasses and glasses and images create the illusion of interacting in 3 dimensions.

11. Outputting Sound Sound card and speakers are needed. The sound card changes digital sound files into an electric current that is sent to the monitor. There are two types of software that allow audio output 1.Speech synthesis software allows the computer to read text files aloud 2.Musical Instrument Digital Interface (MIDI) software allows the computer to create music. You can send instructions to a synthesizer and it plays the music.