ASCII stands for the "American Standard Code for Information Interchange". It was designed in the early 60's, as a standard character-set for computers and hardware devices like teleprinters and tapedrives.
ASCII is a 7-bit character set containing 128 characters.
It contains the numbers from 0-9, the uppercase and lowercase English letters from A to Z, and some special characters.
The character-sets used in modern computers, HTML, and Internet are all based on ASCII.
The following table lists the 128 ASCII characters and their equivalent HTML entity codes.
The ASCII device control characters were originally designed to control hardware devices.
Control characters have nothing to do inside an HTML document.