Friday, August 9, 2019

Input and Output / Introduction to computers

Input and output 
Input device - Translate what people understand into a  form that computers can process.
Keyboard entry:
Keyboard-known as QWERTY, basic input device.
1.       Traditional: full sized, rigid, rectangular keyboard.
2.       Flexible: fold or roll up for easy packing or storage.
3.       Ergonomic:rectangular and a palm rest is provided.
4.       Wireless: transmit input to the system unit through air.
5.        PDA: used to send E-mail, create document more.

Pointing Devices :
Mouse Pointer, location, Arrow 

1.     Mechanical mouse- It has ball on the bottom. Roller rotates and controls the pointer.
2.    Optical mouse-No moving parts,  it emits and senses light to detect mouse movement.
3.    Cordless or wireless mouse- battery powered device. Uses radio waves or infrared light waves to communicate.
        Three devices similar to a mouse  are trackball touch surface and pointing sticks.


Scanning Devices :
Optical scanners - scans and convert documents in to machine readable form.
1.    Flatbed scanner:like a copy machine e. g. adervertising professionals.
2.    Portable scanner: handheld device that slides across the image. Students, lawyers.
UPC : Universal product code electronic cash registers and bar code system using in supermarket. Bar code raiders/wand readers: read bar codes or the vertical zebra-striped marks printed on product.
Character and mark recognition device:
MICR :magnetic Ink character recognition. Used by banks to read unusual numbers on the bottom of checks and deposit slips.
ORC: optical character handheld wand reader.
OMR: optical mark recognition. Mark sensing, sense presence or absence of mark, such as a pencil mark, used to score multiple choice tests.

Image capturing devices:
1.    Digital camera: capture still images. Recorded digitally on cameras memory rather than film.
2.    Digital video camera:capture motion, web cams are specialized digital video cameras that capture images and send them to computer over internet.

Audio input device:
Voice recognition system: use a microphone, a sound card, and special software
MIDI: musical instrument digital interface. Allows musical instrument to connect to the system.


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