These are the standard ASCII control codes, originally defined in ANSI X3.4.
Some serial transmission protocols such as ANPA-1312, Kermit, and XMODEM do make extensive use of control characters SOH, STX, ETX, EOT, ACK, NAK and SYN for purposes approximating their original definitions. Others are unused or have acquired different meanings such as NUL being the C string terminator. Since then, only a few of the original controls have maintained their use: the "whitespace" range of BS, TAB, LF, VT, FF, and CR the BEL code and ESC (but almost always as part of an ESC,'[' CSI representation starting an ANSI escape sequence). This large number of codes was desirable at the time, as multi-byte controls would require implementation of a state machine in the terminal, which was very difficult with contemporary electronics and mechanical terminals.
2.2 C1 control codes for bibliographic useĪSCII defined 32 control characters, plus a necessary extra character for the DEL character, 7F HEX or 01111111 BIN (needed to punch out all the holes on a paper tape and erase it).The ISO/IEC 2022 system of specifying control and graphic characters allows other C0 and C1 sets to be available for specialized applications, but they are rarely used. C1 codes are the range 80 HEX–9F HEX and the default C1 set was originally defined in ECMA-48 (harmonized later with ISO 6429). The codes represent additional information about the text, such as the position of a cursor, an instruction to start a new line, or a message that the text has been received.Ĭ0 codes are the range 00 HEX–1F HEX and the default C0 set was originally defined in ISO 646 ( ASCII). The C0 and C1 control code or control character sets define control codes for use in text by computer systems that use ASCII and derivatives of ASCII. JSTOR ( March 2010) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed.įind sources: "C0 and C1 control codes" – news Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.