Input Devices- Document Readers


  • Optical Character Recognition abbrieviated OCR
  • It is used to scan and translate documents into digital data that is editable.
  • It is mostly used in postal services as it reads the post code and sorts the mail automatically.
  • It is also used for old documents that were written before computers were invented.

Advantages and Disadvantages


  • Easy and quick to sort letters in the post
  • It is understood by humans and computers
  • It reads both shapes and letters
  • It is stored in compact form


  • Not always 100% accurate and requires proof reading before saved and confirmed.
  • Human handwriting is rarely accurately recognizable by OCR, the compputer might confuse different shapes like '5' and 'S'.
  • It is very costly to get through and costs more to proof-read and correct the data


  • Optical Mark Recognition
  • Used for IQ tests and lotto tickets
  • It is used to read marks made by a person in preset positions or boxes on a specialized form.
  • It is also used on school attendance registers and surveys.
  • Very expensive


1.There is a large number of document to justify designing and printing them.
2.The user can only make marks and cannot write any information.
3.OMR can eliminate transcription errors provided the instructions given to users are clear.
4.OMR comes useful when a high amount of forms to be processed is required in a short time.


1.Document for mark reader are complicated to design.
2.input of the data to computer is slow. is difficult for a computer to check marked data.
4.the person putting the marks on the document has to follow the instruction.


  • Magnetic Ink Character Recognition
  • Uses specialised magnetised ink
  • Written in special font
  • Used exclusively in banks on cheques to be able to process them faster.


  • Software can alter the screen while it is running making it more flexible than a printed overlay (concept) keyboard
  • No extra peripherals are needed apart from the touch screen monitor itself
  • MICR can read data even if it's smudged crumbled or dirty.
  • It is hard to reproduce the ink, hence hard to forge cheques.


  • Not suitable for inputting large amounts of data
  • Selecting detailed objects can be difficult with fingers


  • Barcode represent a binary number as a series of thick and thin black lines, with numbers underneath for humans to read.
  • Mostly used in shops for products.
  • It is read by a scanner that reads the data and processes it on the system.
  • The first two digits represent the country of origin, the next five represent manufacturer's code, next five represent the product and package size, last digit is a check digit to confirm that the barcode is read correctly, the amount of digits may vary. The barcode does not contain the price.


  • Fast-selling items can be identified quickly and automatically reordered to meet consumer demand,
  • Slow-selling items can be identified, preventing a build-up of unwanted stock,
  • The effects of repositioning a given product within a store can be monitored, allowing fast-moving more profitable items to occupy the best space,
  • Historical data can be used to predict seasonal fluctuations very accurately.
  • Items may be repriced on the shelf to reflect both sale prices and price increases.
  • This technology also enables the profiling of individual consumers, typically through a voluntary registration of discount cards. While pitched as a benefit to the consumer, this practice is considered to be potentially dangerous by privacy advocates.


  • If the code becomes damaged or misformed it may not be read

Sample Question

1. An OCR scanner is used for scanning and translating printed text onto a computer.
a) Explain how an OCR work

b) Outline one advantage and one disadvantage of using OCR.