This list provides an inventory of character coding standards mainly before modern standards like ISO/IEC 646 etc. Some of these standards have been deeply involved in historic events that still have consequences. One notable example of this is the ITA2 coding used during World War II (1939–1945). The nature of these standards is not as common knowledge like it is for ASCII or EBCDIC or their slang names. While 8-bit is the de facto standard as of 2016, in the past 5-bit and 6-bit were more prevalent or their multiple.
| -- style="width:99%;"--> | Code | Introduction | Width | Usage |
|---|---|---|---|---|
| Morse code | c. 1837–1840 | varies | Electrical telegraphs | |
| Baudot code / ITA1 | 1870 | 5 bits | Piano-like telegraph operation, SIGCUM cipher operation | |
| Chinese telegraph code | 1881 | 4 digits | Chinese telegraph communications | |
| Murray code | 1901 | 5 bits | Machine run telegraph operation using punched paper, moved optimization from minimal operator fatigue to minimal machinery wear | |
| ITA2 | 1924 | 5 bits | Teletypewrite, Telecommunications devices for the deaf (TDD), Telex, Amateur radio, Radioteletype (RTTY), Financial info by Deutsche Börse, Enigma machine and T52 during WWII | |
| BCDIC | 1928 | 6 bits | Introduced with the IBM card | |
| FIELDATA | 1956 | 6/7 bits | Battlefield information (USA) | |
| CDC display code | 1963 | 6 bits | Control Data Corporation computers | |
| DEC SIXBIT/ECMA-1 | 1963 | 6 bits | Digital Equipment | |
| EBCDIC | 1963 | 8 bits | IBM computers | |
| ASCII | data-sort-value="1963" | 1963-06-17 (ASA X3.4-1963) | 7 bits | Teleprinters and computers; original definition of ASCII |
| GOST 10859 | 1964 | 4/5/6/7 bits | Soviet Union | |
| ECMA-6 | data-sort-value="1965" | 1965-04-30 | 7 bits | ASCII localization |
| ISO 646 | data-sort-value="1967" | 1967 (ISO/R646-1967) | 7 bits | ASCII localization |
| ASCII | data-sort-value="1967" | 1967 (USAS X3.4-1967) | 7 bits | Close to "modern" definition of ASCII |
| Transcode | 1967 | 7 bits | IBM data transmission terminal 2780, 3780 | |
| Recommendation V.3 IA5 | 1968 | 7 bits | ||
| MARC-8 | 1968 | 7 bits | Library computer systems | |
| Braille ASCII | 1969 | 6/7 bits | Tactile print for blind persons | |
| JIS X 0201 | 1969 | 6/7 bits | First Japanese electronic character set | |
| ECMA-48 | 1972 | 7 bits | Terminal text manipulation and colors | |
| ISO/IEC 8859 | 1987 | 8 bits | International codes | |
| ISO/IEC 10646 (Unicode) | 1991 | data-sort-value="21" | 21 bits usable, packed into 8/16/32-bit code units | Unified encoding for most of the world's writing systems. When introduced in 1991 then only 16-bit (extension to 21-bit came later). |
| KPS 9566 | 1993 | North Korean 2-byte character code set |