ISO 2047
ISO 2047 is a standard for graphical representation of the control characters for debugging purposes, such as may be found in the character generator of a computer terminal; it also establishes a two-letter abbreviation of each control character. In addition, RFC 1345 "Character Mnemonics & Character Sets" is cited as the ISO 2047 two-letter abbreviation of the control character. ISO 2047, ECMA-17 in Europe, GB/T 3911-1983 in China, that corresponds to KS X 1010 in Korea has been established as a standard. It was enacted "graphical representation of information exchange capabilities for character" JIS X 0209:1976 in Japan, and was abolished on January 20, 2010.
The ISO/IEC 646 three-letter abbreviation, or caret notation are used much more often than this standard.Character Table