|Coding systems are employed by
computers in order to represent various characters,
numbers, and control keys that the computer user selects on the
keyboard. Three of the more popular
coding systems are:
They differ in how many digits or bits they use
to represent a character. Below are some examples:
In each system the character or number is represented by a sequence of binary digits which can only have values of 0 or 1. The ASCII system uses seven 0 or 1 digits or bits to represent the letters of the alphabet, while EBCDIC uses eight bits. BCD uses four bits to represent the numbers 0 to 9.