How do a bar code reader differ from a keyboard as input device?

From the the user's point of view - the bar-code reader is much simpler to use. You simply point the reader at the bar-code - and it scans the sequence of black & white lines, sending data to a computer - which tells the user what the product is.

With a keyboard, you would have to enter the long string of numbers printed under the bar-code - which not only takes more time

• but could be entered wrongly.