The American Standard Code for Information Interchange defines 128 characters that can be represented by 7 bits.
The characters include 33 non-printable control characters such as tab, line feed, carriage return, and 95 printable characters such as the Latin alphabet in upper and lower case, ten Arabic numerals, and some punctuation and special characters.
In 1968, the version of the ASCII standard that is still valid today was defined.
With the “triumphal march” of the computers there was the need to do justice to different languages. Thus 7 bits were no longer sufficient.
With Unicode, a standard was developed that uses up to 32 bits per character and can thus distinguish over four billion characters.