The first 33 ASCII code points are non-printing control codes including the carriage return, line feed, tab, and several obsolete non-printable codes stemming from its origin of representing telegraph codes. The other 95 are printable characters, including digits (0-9), lowercase (a-z) and uppercase (A-Z) letters, and punctuation symbols.

Many computer systems instead use Unicode , which has millions of code points, but the first 128 of these are the same as the ASCII set. UTF-8 superseded ASCII on the Web in 2007.