ascii(7) -- Linux man page
NAMEascii - the ASCII character set encoded in octal, decimal, and hexadecimal
DESCRIPTIONASCII is the American Standard Code for Information Interchange. It is a 7-bit code. Many 8-bit codes (such as ISO 8859-1, the Linux default character set) contain ASCII as their lower half. The international counterpart of ASCII is known as ISO 646.
The following table contains the 128 ASCII characters.
C program '\X' escapes are noted.