Wednesday 15 June 2011

Input and Output

Ergonomic Keyboard
A keyboard that separates the keys into two halves shaped like a wide "V." Some keyboards have a fixed layout, while others are movable. To the touch typist, the layout feels odd at first, but it puts less stress on the hands and wrist and winds up being comfortable for most people.


Ink-Jet Printer

A type of printer that works by spraying ionized ink at a sheet of paper. Magnetized plates in the ink's path direct the ink onto the paper in the desired shapes. Ink-jet printers are capable of producing high quality print approaching that produced by laser printers. A typical ink-jet printer provides a resolution of 300 dots per inch, although some newer models offer higher resolutions.

In general, the price of ink-jet printers is lower than that of laser printers. However, they are also considerably slower. Another drawback of ink-jet printers is that they require a special type of ink that is apt to smudge on inexpensive copier paper.

Because ink-jet printers require smaller mechanical parts than laser printers, they are especially popular as portable printers. In addition, color ink-jet printers provide an inexpensive way to print full-color.



Laser Printer

A laser printer is a popular type of personal computer printer
that uses a non-impact (keys don't strike the paper), photocopier technology. When a document is sent to the printer, a laser beam "draws" the document on a selenium-coated drum using electrical charges. After the drum is charged, it is rolled in toner, a dry powder type of ink. The toner adheres to the charged image on the drum. The toner is transferred onto a piece of paper and fused to the paper with heat and pressure. After the document is printed, the electrical charge is removed from the drum and the excess toner is collected. Most laser printers print only in monochrome. A color laser printer is up to 10 times more expensive than a monochrome laser printer.



Magnetic-ink Character

Magnetic ink characters (MIC) are numbers, letters, or symbols that are usually used in conjunction with magnetic ink recognition technology. This technology is primarily used by the banking industry to read and sort checks using a process called Magnetic Ink Character Recognition or MICR. MICs are printed at the bottom of a check in the MICR line and are usually 3 or 4 sets of numbers and symbols.




Optical-character Recognition
Often abbreviated OCR, optical character recognition refers to the branch of computer science that involves reading text from paper and translating the images into a form that the computer can manipulate (for example, into ASCII codes). An OCR system enables you to take a book or a magazine article, feed it directly into an electronic computer file, and then edit the file using a word processor.



All OCR systems include an optical scanner for reading text, and sophisticated software for analyzing images. Most OCR systems use a combination of hardware (specialized circuit boards) and software to recognize characters, although some inexpensive systems do it entirely through software. Advanced OCR systems can read text in large variety of fonts, but they still have difficulty with handwritten text.



The potential of OCR systems is enormous because they enable users to harness the power of computers to access printed documents. OCR is already being used widely in the legal profession, where searches that once required hours or days can now be accomplished in a few seconds.









Optical-mark Recognition
Optical Mark Recognition, detects hand written response marks made in checkboxes of bubble sheet forms. The forms are scanned and the response form images  are automatically processed, into managable response data [ A;B;C;D and / or  form scoring for the correct answers].



Optical Mark Recognition saves hours of time when collecting response data from check-boxes of bubble sheet assessments, tests and surveys and is much more accurate than manually processing responses made on questionnaire forms. The main objective of Optical Mark Recognition technology, is eliminating data entry once the response form papers have been collected.

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