To standardize the storing of alphanumeric characters, the American Standard Code for Information Interchange (ASCII) was created. It defined a unique binary 7-bits number for each storable character to support the numbers from 0-9, the upper/lower case English alphabet (a-z, A-Z), and some special characters like ! $ + – ( ) @ < > .
Because the limited character sets in ASCII Text and its non-compatibility in multilingual environments, the Unicode Consortium developed the Unicode Standard. The Unicode Standard covers (almost) all the characters, punctuations, and symbols in the world.