ASCII code with examples

ASCII (American Standard Code for Information Interchange) is a 7-bit alphanumeric code that represents $2^7 = 128$ characters: letters, digits, punctuation and control codes. It is the standard code for text in computers and for data exchange between devices.

Groups of characters

• 0–31 and 127: control characters (e.g. LF = 10, CR = 13, ESC = 27, DEL = 127).
• 32: space; 33–47, 58–64, 91–96 and 123–126: punctuation and symbols.
• 48–57: digits '0'–'9' (011 0000 to 011 1001).
• 65–90: capital letters 'A'–'Z'; 97–122: small letters 'a'–'z'.

Examples

So "CAT" is stored as 43H 41H 54H. Lower-case letters are 32 (bit 5) higher than capitals. An 8th bit is often added as a parity bit or for the extended ASCII set (256 characters).