ANSI escape codes are used for adding colour to your BBS, and moving around the screen. You can use ANSI escape codes to add things like lightbars, windows, full screen editors and more.
ANSI escape codes are prefixed by the ESC (0x1B) character and a square opening brace, followed by a list of paramaters, and then a command, for example:
This code changes the forground colour to bright green. It has 2 paramaters, 1 meaning bright (or bold) and 32 meaning green. The command 'm' changes the colour.