Non-printing character
A non-printing character, also called a control character, is a number that represents a non-written or non-printable character (letter, number, or symbol). Typically these control characters are interrupted by the sending or receiving device to produce the desired results.
Some control characters represent audible or silent signals to be sent or received. Other control characters (ASCII code) include the backspace, line feed, form feed, carriage return, escape, and delete.
Also see: ASCII, Character, Null character, Special character