The ASCII Character Set

ASCII stands for American Standard Code for Information Interchange. The ASCII character set originally used seven bits to represent each character, allowing for 128 unique characters.
Later ASCII evolved so that all eight bits were used which allows for 256 characters.
http://en.wikipedia.org/wiki/Ascii

ASCII stands for American Standard Code for Information Interchange. The ASCII character set originally used seven bits to represent each character, allowing for 128 unique characters.