The ASCII character set
ASCII stands for the American Standard Code for Information Interchange.
ASCII is a well-known character encoding based on the English alphabet. Characters are encoded in a single byte, using the 7 lower bits only.
Up to 127 characters, printable and non-printable (like control characters), are defined in ASCII.
Nearly all other character sets (using 8 bits or multiple bytes such as UTF-8) define the first 127 characters as the ASCII character set.
Aliases for ASCII include ISO646-US, ANSI_X3.4-1968, IBM367, cp367, and more.