Input Output Devices

Question 1

what are the four main input output devices?

Answer 1

• Barcode reader
• Digital camera
• Lazer printer
• RFID

Question 2

what are the operations of a barcode reader.

Answer 2

1. a light from a lazer illuminates the barcode
2. more light is reflected from the white areas than the black areas
3. the reflected light is captured by one or more of the photoelectric cells that generate a set of electrical pulses that correspond to the black of the white stripes in the barcode
4. these pulses are processed and converted into a binary number that represents the code

Question 3

what is the principle that barcode readers work on?

Answer 3

the principle of
reflected light

Question 4

what are the three different types of barcode systems and where are they used?

Answer 4

• UPC-A (Universal Product Code Version “A”) - used in retail and warehousing
• EAN (European Article Number) - used in retail and warehousing
• Code 128 - used in transport and shipment tracking