Юникодтың басқару символдары (C0 және C1 жиынтықтары)

Control characters, ranging from U+0000 to U+001F (C0) and U+0080 to U+009F (C1) in Unicode

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. 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. C0 codes are the range 00HEX–1FHEX and the default C0 set was originally defined in ISO 646 (ASCII). C1 codes are the range 80HEX–9FHEX and the default C1 set was originally defined in ECMA 48 (harmonized later with ISO 6429). 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.

ASCII defined 32 control characters, plus a necessary extra character for the DEL character, 7FHEX or 01111111BIN (needed to punch out all the holes on a paper tape and erase it). 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. Only a few codes have maintained their use: BEL, ESC, and the "Format Effector" (FEn) characters BS, TAB, LF, VT, FF, and CR. Others are unused or have acquired different meanings such as NUL being the C string terminator. Some data transfer protocols such as ANPA 1312, Kermit, and XMODEM do make extensive use of SOH, STX, ETX, EOT, ACK, NAK and SYN for purposes approximating their original definitions; and some file formats use the "Information Separators" (ISn) such as the Unix info format and Python's string method. The names of some codes were changed in ISO 6429:1992 (or ECMA 48:1991) to be neutral with respect to writing direction. The abbreviations used were not changed, as the standard had already specified that those would remain unchanged when the standard is translated to other languages. In this table both new and old names are shown for the renamed controls (the old name is the one matching the abbreviation). + ASCII control codes, originally defined in ANSI X3.4. Abbreviations Name Description000NUL␀Null Does nothing. The code of blank paper tape, and also used for padding to slow transmission.101TC1, SOH␁Start of Heading First character of the heading of a message.202TC2, STX␂Start of Text Terminates the header and starts the message text.303TC3, ETX␃End of Text Ends the message text, starts a footer (up to the next TC character). May place terminals on standby. e. g. in Perl. and the corresponding control picture code point is called SYMBOL FOR BELL. Perl subsequently switched to using BELL for the emoji in version 5.18.␇Bell, AlertCall for attention from an operator.808FE0, BS␈BackspaceMove one position leftwards. Next character may overprint or replace the character that was there.909FE1, HT␉Character Tabulation,Horizontal TabulationMove right to the next tab stop.100AFE2, LF␊Line FeedMove down to the same position on the next line (some devices also moved to the left column).110BFE3, VT␋Line Tabulation,Vertical TabulationMove down to the next vertical tab stop.120CFE4, FF␌Form FeedMove down to the top of the next page.130DFE5, CR␍Carriage ReturnMove to column zero while staying on the same line.140ESO, LS0␎Shift OutSwitch to an alternative character set.150FSI, LS1␏Shift InReturn to regular character set after SO.1610␐Data Link Escape Cause a limited number of contiguously following characters to be interpreted in some different way.1711DC1, XON␑Device Control OneTurn on (DC1 and DC2) or off (DC3 and DC4) devices. Teletype used these for the paper tape reader and the paper tape punch. The first use became the de facto standard for software flow control.1812DC2, TAPE␒Device Control Two1913DC3, XOFF␓Device Control Three2014DC4, TAPE␔Device Control Four2115TC8, NAK␕Negative Acknowledge Negative response to a sender, such as a detected error.2216TC9, SYN␖Synchronous Idle Sent in synchronous transmission systems when no other character is being transmitted.2317TC10, ETB␗[[End of Transmission Block character End of a transmission block of data when data are divided into such blocks for transmission purposes.2418CAN␘Cancel Indicates that the data preceding it are in error or are to be disregarded.2519EM ␙End of medium Indicates on paper or magnetic tapes that the end of the usable portion of the tape had been reached. attempted to define a method so an 8 bit "extended ASCII" code could be converted to a corresponding 7 bit code, and vice versa. (i. e. all but the C0 control codes), to be the characters that an 8 bit environment would print if it used the same code with the high bit set. This meant that the range through could not be printed in a 7 bit environment, thus it was decided that no alternative character set could use them, and that these codes should be additional control codes, which become known as the C1 control codes. To allow a 7 bit environment to use these new controls, the sequences ESC @ through ESC were to be considered equivalent. and JIS X 0211 (formerly JIS C 6323). Symbolic names defined by and early drafts of ISO 10646, but not in ISO/IEC 6429 (, and ) are also used. @12880PAD Proposed as a "padding" or "high byte" for single byte characters to make them two bytes long for easier interoperability with multiple byte characters. Extended Unix Code (EUC) occasionally uses this. A12981HOPFollows a graphic character where a line break is permitted. Roughly equivalent to a soft hyphen or zero width space except it does not define what is printed at the line break. C13183NBHNo Break HereFollows the graphic character that is not to be broken. See also word joiner. D13284INDIndexMove down one line without moving horizontally, to eliminate ambiguity about the meaning of LF. E13385NELNext LineEquivalent to CR+LF, to match the EBCDIC control character. F13486SSAStart of Selected AreaUsed by block oriented terminals. In xterm moves to the lower left corner of the screen, since certain software assumes this behaviour. G13587ESAEnd of Selected AreaH13688HTSCharacter Tabulation Set, Horizontal Tabulation SetSet a tab stop at the current position. I13789HTJRight justify the text since the last tab against the next tab stop. J1388AVTSLine Tabulation Set, Vertical Tabulation SetSet a vertical tab stop. K1398BPLDPartial Line Forward, Partial Line Down To produce subscripts and superscripts in ISO/IEC 6429. Subscripts use PLD text PLU while superscripts use PLU text PLD. L1408CPLUPartial Line Backward, Partial Line UpM1418DRIReverse Line Feed, Reverse IndexMove up one line. N1428ESS2Next character is from the G2 or G3 sets, respectively. O1438FSS3P14490DCSDevice Control StringFollowed by a string of printable characters (0x20 through 0x7E) and format effectors (0x08 through 0x0D), terminated by ST (0x9C). Xterm defined a number of these. Q14591PU1Private Use 1Reserved for private function agreed on between the sender and the recipient of the data. R14692PU2Private Use 2S14793STSSet Transmit StateT14894CCHCancel characterDestructive backspace, to eliminate ambiguity about meaning of U14995MWMessage WaitingV15096SPAStart of Protected AreaUsed by block oriented terminals. W15197EPAEnd of Protected AreaX15298SOSStart of StringFollowed by a control string terminated by (0x9C) which (unlike , , or ) may contain any character except SOS or ST. Y15399SGC, SGCISingle Graphic Character IntroducerIntended to allow an arbitrary Unicode character to be printed; it would be followed by that character, most likely encoded in UTF 1. Kermit used APC to transmit commands.^1589EPMPrivacy Message 1599FAPCApplication Program Command

The ISO/IEC 2022 (ECMA 35) extension mechanism allowed escape sequences to change the C0 and C1 sets. The standard C0 control character set shown above is chosen with the sequence and the above C1 set chosen with the sequence SP and DEL "fixed" coded characters, which are available in their ASCII locations in all encodings that conform to the standard. It also specifies that if a C0 set included transmission control (TCn) codes, they must be encoded at their ASCII locations and could not be put in a C1 set, and any new transmission controls must be in a C1 set. and others replaced EM and GS with SS2 and SS3 so these functions could be used in a 7 bit environment. Some sets replaced FS with SS2, (same as ANPA 1312). The now withdrawn JIS C 6225, designated JIS X 0207 in later sources. replaced FS with CEX or "Control Extension" which introduces control sequences for vertical text behaviour, superscripts and subscripts and for transmitting custom character graphics. Various specialised C1 control code sets are registered for use by Videotex formats. Although the New Line (NL) does translate to the ISO/IEC 6429 (although it is often swapped with LF, following UNIX line ending convention),