ISO/IEC 2022 - Knowledge

3792: 1350:. The LS2, LS3, LS1R, LS2R and LS3R shifts are registered as single control functions and are always encoded as the escape sequences listed below, whereas the others are part of a C0 or C1 control code set (as shown below, SI (LS0) and SO (LS1) are C0 controls and SS2 and SS3 are C1 controls), meaning that their coding and availability may vary depending on which control sets are designated: they must be present in the designated control sets if their functionality is used. The C1 controls themselves, as mentioned above, may be represented using escape sequences or 8-bit bytes, but not both. 753:'s property that a seven-bit character representation will normally be able to represent 94 graphic (printable) characters (in addition to space and 33 control characters); if only the C0 control codes (narrowly defined) are excluded, this can be expanded to 96 characters. Using two bytes, it is thus possible to represent up to 8,836 (94×94) characters; and, using three bytes, up to 830,584 (94×94×94) characters. Though the standard defines it, no registered character set uses three bytes (although 12036: 14594: 11947: 5045:. It is based on ISO 2022, and only character sets which conform to the ISO 2022 structure can have EUC forms. Up to four coded character sets can be represented (in G0, G1, G2 and G3). The G0 set is invoked over GL, the G1 set is invoked over GR, and the G2 and G3 sets are (if present) invoked using the single shifts SS2 and SS3, which are used as CR bytes (i.e. 0x8E and 0x8F respectively) and invoke over GR (not GL). Locking shift codes are not used. 4850: 1820:" (DRCS) defined by prior agreement, which is also considered private use. A graphical set being considered a DRCS implies that it represents a font of exact glyphs, rather than a set of abstract characters. The manner in which DRCS sets and associated fonts are transmitted, allocated and managed is not stipulated by ISO/IEC 2022 / ECMA-35 itself, although it recommends allocating them sequentially starting with 5662:

that if a stream that ends in a multi-byte character is concatenated with one that starts with a multi-byte character, a pair of escape codes are generated switching to ASCII and immediately away from it. However, as stipulated in Unicode Technical Report #36 ("Unicode Security Considerations"), pairs of ISO 2022 escape sequences with no characters between them should generate a

1361:. This coding is currently recommended by ISO/IEC 2022 / ECMA-35 for applications requiring 7-bit single-byte representations of SS2 and SS3, and may also be used for SS2 only, although older code sets with SS2 at 0x1C also exist, and were mentioned as such in an earlier edition of the standard. The 0x8E and 0x8F coding of the single shifts as shown below is mandatory for 987:, appear in the C0 set, they are required to appear at their ISO 6429 / ECMA-48 locations. Inclusion of transmission control characters in the C0 set, besides the ten included by ISO 6429 / ECMA-48 (namely SOH, STX, ETX, EOT, ENQ, ACK, DLE, NAK, SYN and ETB), or inclusion of any of those ten in the C1 set, is also prohibited by the ISO/IEC 2022 / ECMA-35 standard. 4551:. The additions made by JIS X 0213 compared to the base JIS X 0208 standard resulted in a new registration being made for the extended JIS plane 1, while the new plane 2 received its own registration. The further additions to plane 1 in the 2004 edition of the standard resulted in an additional registration being added to a further revision of the profile, dubbed 808:, where two decimal numbers in the range 00–15 (each corresponding to a single hexadecimal digit) are separated by a slash. Hence, for instance, codes 2/0 (0x20) through 2/15 (0x2F) inclusive may be referred to as "column 02". This is the notation used in the ISO/IEC 2022 / ECMA-35 standard itself. They may be described elsewhere using 968:, on the basis that it leaves the graphical character repertoire undefined. ISO/IEC 4873 / ECMA-43 does, however, permit the use of the GCC function provided that the sequence of characters is kept the same and merely displayed in one space, rather than being over-stamped to form a character with a different meaning. 2929:) is included in the designation sequences of codes which do not use that byte sequence to return to ISO 2022; they may have their own means to return to ISO 2022 (such as a different or padded sequence) or none at all. All existing registrations of the latter type (as of 2019) are either transparent raw data, 4950:

Character set designation escape sequences are used for identifying or switching between versions during information interchange only if required by a further protocol, in which case the standard requires an ISO/IEC 2022 announcer sequence specifying the ISO/IEC 4873 level, followed by a complete set

1650:

The names "locking shift zero" (LS0) and "locking shift one" (LS1) refer to the same pair of C0 control characters (0x0F and 0x0E) as the names "shift in" (SI) and "shift out" (SO). However, the standard refers to them as LS0 and LS1 when they are used in 8-bit environments and as SI and SO when they

5661:

Concatenation can pose issues. Profiles such as ISO-2022-JP specify that the stream starts in the ASCII state and must end in the ASCII state. This is necessary to ensure that characters in concatenated ISO-2022-JP and/or ASCII streams will be interpreted in the correct set. This has the consequence

4935:

In cases where duplicate characters are available in different sets, the current edition of ISO/IEC 4873 / ECMA-43 only permits using these characters in the lowest numbered working set which they appear in. For instance, if a character appears in both the G1 set and the G3 set, it must be used from

1685:

Registration of coded character sets with the ISO-IR registry identifies the documents specifying the character set or control function associated with an ISO/IEC 2022 non‑private-use escape sequence. This may be a standard document; however, registration does not create a new ISO standard, does not

979:

A C0 control set must contain the ESC (escape) control character at 0x1B (a C0 set containing only ESC is registered as ISO-IR-104), whereas a C1 control set may not contain the escape control whatsoever. Hence, they are entirely separate registrations, with a C0 set being only a C0 set and a C1 set

668:

A specific implementation does not have to implement all of the standard; the conformance level and the supported character sets are defined by the implementation. Although many of the mechanisms defined by the ISO/IEC 2022 standard are infrequently used, several established encodings are based on a

5616:

Due to the stateful nature of ISO/IEC 2022, an identical and equivalent character may be encoded in different character sets, which may be designated to any of G0 through G3, which may be invoked using single shifts or by using locking shifts to GL or GR. Consequently, characters can be represented

1858:

There are additional (rarely used) features for switching control character sets, but this is a single-level lookup, in that (as noted above) the C0 set is always invoked over CL, and the C1 set is always invoked over CR or by using escape codes. As noted above, it is required that any C0 character

912:

In a 96- or 96-character set, the bytes 0x20 through 0x7F when GL-invoked, or 0xA0 through 0xFF when GR-invoked, are allocated to and may be used by the set. In a 94- or 94-character set, the bytes 0x20 and 0x7F are not used. When a 96- or 96-character set is invoked in the GL region, the space and

5612:

Since ISO/IEC 2022 is a stateful encoding, a program cannot jump in the middle of a block of text to search, insert or delete characters. This makes manipulation of the text very cumbersome and slow when compared to non-stateful encodings. Any jump in the middle of the text may require a backup to

5590:

As ISO/IEC 2022's entire range of graphical character encodings can be invoked over GL, the available glyphs are not significantly limited by an inability to represent GR and C1, such as in a system limited to 7-bit encodings. It accordingly enables the representation of large set of characters in

3931:

Use of the two characters added in JIS X 0208-1990 is permitted, but without including the IRR sequence, i.e. using the same escape sequence as JIS X 0208-1983. Also, due to being registered before designating multi-byte sets except to G0 was possible, the escapes for JIS X 0208 do not include the

4175:

implements nine 7-bit ISO 2022 based encodings for Japanese, each using a different set of escape sequences: IBM-956, IBM-957, IBM-958, IBM-959, IBM-5052, IBM-5053, IBM-5054, IBM-5055 and ISO-2022-JP, which are collectively termed "TCP/IP Japanese coded character sets". CCSID 9148 is the standard

3316:

a specific code structure, or a specific group of ISO 2022 facilities which are used in a particular code version. Although announcements can be combined, certain contradictory combinations (specifically, using locking shift announcements 16–23 with announcements 1, 3 and 4) are prohibited by the

734:

Specific profiles such as ISO-2022-JP may impose extra conditions, such as that the current character set is reset to US-ASCII before the end of a line. Furthermore, the escape sequences declaring the national character sets may be absent if a specific ISO-2022-based encoding permits or requires

990:

A C0 control set is invoked over the CL range 0x00 through 0x1F, whereas a C1 control function may be invoked over the CR range 0x80 through 0x9F (in an 8-bit environment) or by using escape sequences (in a 7-bit or 8-bit environment), but not both. Which style of C1 invocation is used must be

1630:

Although officially considered shift codes and named accordingly, single-shift codes are not always viewed as shifts, and they may simply be viewed as prefix bytes (i.e. the first bytes in a multi-byte sequence), since they do not require the encoder to keep the currently active set as

782:

number is included at the beginning. The escape sequences do not only declare which character set is being used, but also whether the set is single-byte or multi-byte (although not how many bytes it uses if it is multi-byte), and also whether each byte has 94 or 96 permitted values.

4642:

are defined in RFC 1922, dated 1996. They are 7-bit encodings making use both of the Shift Out and Shift In functions (to shift between G0 and G1), and of the 7-bit escape code forms of the single-shift functions SS2 and SS3 (to access G2 and G3). They support the character sets

731:) and follow the patterns defined within the standard. Character encodings making use of these escape sequences require data to be processed sequentially in a forward direction, since the correct interpretation of the data depends on previously encountered escape sequences. 3065:) formats which do not follow the ISO/IEC 2022 structure. These include UTF-8 (which does not reserve the range 0x80–0x9F for control characters), its predecessor UTF-1 (which mixes GR and GL bytes in multi-byte codes), and UTF-16 and UTF-32 (which use wider coding units). 1323:

By default, GL codes specify G0 characters and GR codes (where available) specify G1 characters; this may be otherwise specified by prior agreement. The set invoked over each area may also be modified with control codes referred to as shifts, as shown in the table below.

4884:

Level 2, which includes a (94-character or 96-character) single-byte G2 and/or G3 set in addition to a mandatory G1 set. Only the single-shift functions SS2 and SS3 are permitted (i.e. locking shifts are forbidden), and they invoke over the GL region (including

916:

Registration of a set as a 96-character set does not necessarily mean that the 0x20/A0 and 0x7F/FF bytes are actually assigned by the set; some examples of graphical character sets which are registered as 96-sets but do not use those bytes include the G1 set of

897:", which can be represented using an escape sequence, is followed by zero or more bytes in the range 0x30–0x3F, then zero or more bytes in the range 0x20–0x2F, then by a single byte in the range 0x40–0x7E, the entire sequence being called a "control sequence". 812:, as is often used in this article, or using the corresponding ASCII characters, although the escape sequences are actually defined in terms of byte values, and the graphic assigned to that byte value may be altered without affecting the control sequence. 5646:) is masked until it is decoded to Unicode, which may allow it to bypass sanitisation. Use of this encoding is thus treated as suspicious by malware protection suites, and 7-bit ISO 2022 data (except for ISO-2022-JP) is mapped in its entirety to the 4946:

should be used instead for levels 2 and 3 of ISO/IEC 4873. ISO/IEC 10367:1991 includes G0 and G1 sets matching those used by the first 9 parts of ISO/IEC 8859 (i.e. those which existed as of 1991, when it was published), and some supplementary sets.

4051:. The WHATWG/HTML5 variant permits decoding JIS X 0201 katakana in ISO-2022-JP input, but converts the characters to their JIS X 0208 equivalents upon encoding. Microsoft's code page for ISO-2022-JP with JIS X 0201 kana additionally permitted is 843:

SP (0x20) are designated "fixed" coded characters and are always available when G0 is invoked over GL, irrespective of what character sets are designated. They may not be included in graphical character sets, although other sizes or types of

1035:), although no "3Ft" sequences are currently assigned (as of 2019). Some of these are specified in ECMA-35 (ISO 2022 / ANSI X3.41), others in ECMA-48 (ISO 6429 / ANSI X3.64). ECMA-48 refers to these as "independent control functions". 1666:(ISO-IR) lists graphical character sets, control code sets, single control codes and so forth which have been registered for use with ISO/IEC 2022. The procedure for registering codes and sets with the ISO-IR registry is specified by 4662:

The basic ISO-2022-CN profile uses ASCII as its G0 (shift in) set, and also includes GB 2312 and the first two planes of CNS 11643 (due to these two planes being sufficient to represent all traditional Chinese characters from common

800:

allow any of a large registry of graphic character sets to be "designated" into one of four working sets, named G0 through G3, and shorter control sequences specify the working set that is "invoked" to interpret bytes in the stream.

4829:

and related attacks, which utilize a difference in encoding support between the client and server. Although the same security concern (allowing sequences of ASCII bytes to be interpreted differently) also applies to ISO-2022-JP and

3072:. However, the only codes currently specified by ISO/IEC 10646 are the level-3 codes for UTF-8, UTF-16 and UTF-32 and the unspecified-level code for UTF-8, with the rest being listed as deprecated. ISO/IEC 10646 stipulates that the 823:. The terms "CL" (0x00–0x1F) and "CR" (0x80–0x9F) are defined for the control ranges, but the CL range always invokes the primary (C0) controls, whereas the CR range always either invokes the secondary (C1) controls or is unused. 998:

In the latter case, single control functions from the C1 control code set are invoked using "type Fe" escape sequences, meaning those where the ESC control character is followed by a byte from columns 04 or 05 (that is to say,

4880:

Level 1, which includes a C0 set, the ASCII G0 set, an optional C1 set and an optional single-byte (94-character or 96-character) G1 set. G0 is invoked over GL, and G1 is invoked over GR. Use of shift functions is not

5624:

and several e-mail clients, use a variant of ISO-2022 (e.g. "ISO 2022 IR 100") in addition to supporting several other encodings. This type of variation makes it difficult to portably transfer text between computer

5098:

The EUC code itself does not make use of the announcer or designation sequences from ISO 2022; however, it corresponds to the following sequence of four announcer sequences, with meanings breaking down as follows.

7877:, pp. 229–230, Chapter 4 ("Encoding Methods"), section "ISO-2022 encoding" "Those encodings that have been extensively used in the past, or continue to be used today for some purposes, have been highlighted." 4927:

IRV (synchronised with ASCII since 1991) at ISO/IEC 4873 Level 1 with no C1 or G1 set, i.e. using the IRV in an 8-bit environment in which shift codes are not used and the high bit is always zero, is known as

991:

specified in the definition of the code version. For example, ISO/IEC 4873 specifies CR bytes for the C1 controls which it uses (SS2 and SS3). If necessary, which invocation is used may be communicated using

653:

Specific escape code formats for identifying individual character sets, for announcing the use of particular encoding features or subsets, and for interacting with or switching to other encoding systems.

643:

A format for encoding these sets in the same encoding system when only 7 bits are available per byte, and a method for transforming any conformant character data to pass through such a 7-bit environment,

8827: 8061: 1635:, unlike locking shift codes. In 8-bit environments, either GL or GR, but not both, may be used as the single-shift area. This must be specified in the definition of the code version. For instance, 15263: 13920: 5591:

such a system. Generally, this 7-bit compatibility is not really an advantage, except for backwards compatibility with older systems. The vast majority of modern computers use 8 bits for each byte.

3286:

for UTF-16), i.e. the coding of the standard return sequence does not conform exactly to ISO/IEC 2022. For this reason, the designations for UTF-16 and UTF-32 use a without-standard-return syntax.

521:) do not. Control codes in ISO 2022 are always represented with a single byte, regardless of the number of bytes used for graphical characters. CJK encodings used in 7-bit environments which use 3282:

Although use of a variant of the standard return sequence from UTF-16 and UTF-32 is permitted, the bytes of the escape sequence must be padded to the size of the code unit of the encoding (i.e.

1859:

set include the ESC character at position 0x1B, so that further changes are possible. The control set designation sequences (as opposed to the graphical set ones) may also be used from within

5598:

by using sequence codes to switch between discrete encodings for different East Asian languages. This avoids the issues associated with unification, such as difficulty supporting multiple

1717:

to identify Unicode. The textual representation of the escape sequence, included in the third element of the FPI, will be recognised by SGML implementations for supported character sets.

1353:

Alternative encodings of the single-shifts as C0 control codes are available in certain control code sets. For example, SS2 and SS3 are usually available at 0x19 and 0x1D respectively in

941:

Characters are expected to be spacing characters, not combining characters, unless specified otherwise by the graphical set in question. ISO 2022 / ECMA-35 also recognizes the use of the

882:

byte, or absence thereof, determines the type of escape sequence; it might, for instance, designate a working set, or denote a single control function. In all types of escape sequences,

6091:

In earlier editions, 96-character sets did not exist, and the escape codes now used for 96-character sets were reserved as space for additional 94-character sets. Accordingly, the

7124: 4889:

20 and 0x7F in the case of a 96-set). SS2 and SS3 must be available in C1 at 0x8E and 0x8F respectively. This minimal required C1 set for ISO 4873 is registered as ISO-IR-105.

913:

delete characters (codes 0x20 and 0x7F) are not available until a 94- or 94-character set (such as the G0 set) is invoked in GL. 96-character sets cannot be designated to G0.

6082:, adjusted to the range 1-63, indicates which (upwardly compatible) revision of the immediately-following registration is needed, so that old systems know that they are old. 1023:); these have permanently assigned meanings rather than depending on the C0 or C1 designations. Registration of control functions to type "Fs" sequences must be approved by 491:"), are written using far more characters than the maximum of 256 which can be represented in a single byte, and were first represented on computers with language-specific 11565: 7678: 6765: 6095:

sequence was defined in early editions of the standard as designating further 94-character sets to G0. Since 96-character sets cannot be designated to G0, this first

6423: 4097:

is a multilingual extension of ISO-2022-JP, defined in RFC 1554 (dated 1993), which permits the following escape sequences in addition to the ISO-2022-JP ones. The

2907:

A sequence is also defined for returning to ISO/IEC 2022; the registrations which support this sequence as encoded in ISO/IEC 2022 comprise (as of 2019) various

349:

control code, which can likewise be used for in-band instructions. Specific sets of control codes and escape sequences designed to be used with ISO 2022 include

11981: 4892:

Level 3, which permits the GR locking-shift functions LS1R, LS2R and LS3R in addition to the single shifts, but otherwise has the same restrictions as level 2.

778:

form, which comprises two numbers between 1 and 94 inclusive, specifying a row and cell of that character within the zone. For a three-byte set, an additional

6226: 4074:

or setting the eighth bit (GR-invoked), respectively. They are not widely used; JIS X 0208 support in extended 8-bit JIS X 0201 is more commonly achieved via

8831: 8053: 1339:), although some instead have GR codes specifying G2 characters, with the corresponding 7-bit code using a single-shift code to access the second set (e.g. 10410: 8806: 4951:

of escapes specifying the character set designations for C0, C1, G0, G1, G2 and G3 respectively (but omitting G2 and G3 designations for level 1), with an

4809:

ISO-2022-KR and ISO-2022-CN are used less frequently than ISO-2022-JP, and are sometimes deliberately not supported due to security concerns. Notably, the

264: 4101:

parts are 96-character sets which cannot be designated to G0, and are accessed from G2 using the 7-bit escape sequence form of the single-shift code SS2:

15133: 13432: 8013: 8921: 815:

Byte values from the 7-bit ASCII graphic range (hexadecimal 0x20–0x7F), being on the left side of a character code table, are referred to as "GL" codes

10247: 1643:

specifies GR. In 7-bit environments, only GL is used as the single-shift area. If necessary, which single-shift area is used may be communicated using

8962: 735:

this, and dictates that particular national character sets are to be used. For example, ISO-8859-1 states that no defining escape sequence is needed.

1847:

were all registered when the contemporary version of the standard allowed multi-byte sets only in G0, so must be accepted in place of the sequences

15128: 13427: 11356: 6197: 4900:

invariant positions were preserved, that the other positions were assigned to spacing (not combining) characters, that 0x23 was assigned to either

568:

Using 8-bit bytes, but not representing the C1 codes in their single-byte forms specified in ISO 2022 (most UTFs, one exception being the obsolete

14630: 13649: 9547: 9455: 9416: 9377: 9282: 9190: 9158: 9127: 7059: 13437: 8090: 4790:(for multi-byte character sets) specifies the type of character set and working set that is designated to. In the above examples, the character 12932: 12310: 10355: 9897: 9329: 8949: 8663: 8414: 8388: 8362: 8336: 8206: 1751:

byte (or, for a multi-byte set, the first two) identifies the type of character set and the working set it is to be designated to, whereas the

976:

Control character sets are classified as "primary" or "secondary" control code sets, respectively also called "C0" and "C1" control code sets.

284: 8863: 8310: 8284: 8258: 8232: 5635:

transformation format compatible with ISO/IEC 2022's representation of 8-bit control characters, has various disadvantages in comparison with

4942:

defines complete encodings at level 1 of ISO/IEC 4873, and does not allow for use of multiple ISO/IEC 8859 parts together. It stipulates that

12010: 10430: 9944: 1761:

bytes) identify the character set itself, as assigned in the ISO-IR register (or, for the private-use escape sequences, by prior agreement).

8618: 3815:, of which ISO-2022-JP and ISO-2022-KR have been extensively used in the past. A number of other variants are defined by vendors, including 384:). It is designed to be usable in both 8-bit environments and 7-bit environments (those where only seven bits are usable in a byte, such as 7890: 5674:, has led to interoperability issues, with unexpected "�" characters being generated where two ISO-2022-JP streams have been concatenated. 3811:

Six 7-bit ISO 2022 code versions (ISO-2022-CN, ISO-2022-CN-EXT, ISO-2022-JP, ISO-2022-JP-1, ISO-2022-JP-2 and ISO-2022-KR) are defined by

1303:) are reserved for single private use control codes, by prior agreement between parties. Several such sequences of both types are used by 727:

registry (except for those set apart for private use, the meanings of which are defined by vendors, or by protocol specifications such as

13154: 7863: 2884:(which happens to be the NATS control set for newspaper text transmission) is not the same as the C1 control character set designated by 7457: 4920:

is compliant with earlier editions. This was subsequently changed to fully specify the ISO/IEC 646:1991 IRV / ISO-IR No. 6 set (ASCII).

11974: 9919:: a document on encoding Chinese, Japanese, and Korean (CJK) languages, including a discussion of the various variants of ISO/IEC 2022. 4955:-byte of 0x7E denoting an empty set. Each ISO/IEC 4873 level has its own single ISO/IEC 2022 announcer sequence, which are as follows: 1686:

commit the ISO or IEC to adopt it as an international standard, and does not commit the ISO or IEC to add any of its characters to the

14124: 7118: 1785:

have been assigned. At the other extreme, no multibyte 96-sets have been registered, so the sequences below are strictly theoretical.

15487: 14229: 14149: 13940: 13935: 13781: 8775: 288: 4040: 819:

while bytes from the "high ASCII" range (0xA0–0xFF), if available (i.e. in an 8-bit environment), are referred to as the "GR" codes

13947: 8461: 257: 8595:, p. 23, annex E ("Main differences between the second edition (1985) and the present (third) edition of this ECMA Standard") 1792:

bytes, in this case for private-use character set definitions (which might include unregistered sets defined by protocols such as

12301: 11657: 11411: 9907: 9652: 9639: 9631: 9610: 9589: 9568: 9533: 9512: 9494: 9476: 9441: 9402: 9363: 9342: 9321: 9308: 9300: 9268: 9207: 8891: 8710: 7041: 5654:

to prevent attacks. Restricted ISO 2022 8-bit code versions which do not use designation escapes or locking shift codes, such as

8790: 14937: 14480: 12670: 11647: 9069: 9035: 9018: 9001: 7670: 3827:

encoding standard retains support for it, in contrast to mapping ISO-2022-KR, ISO-2022-CN and ISO-2022-CN-EXT entirely to the

15523: 12842: 11967: 11396: 10350: 9463: 9141:

ISO/IEC FDIS 8859-10: Information Technology — 8-bit single-byte coded graphic character sets — Part 10: Latin alphabet No. 6

8984: 6757: 5556:

for fixed-length encodings using one through four bytes respectively. Rather than using another escape sequence to return to

364:

ISO 2022 itself also defines particular control codes and escape sequences which can be used for switching between different

8182: 3321:

level announcements 12–14 (which fully specify the permissible structural features). Announcement sequences are as follows:

3068:

Several codes were also registered for subsets (levels 1 and 2) of UTF-8, UTF-16 and UTF-32, as well as for three levels of

15238: 14549: 14350: 13873: 13256: 12847: 12817: 11530: 9170: 5560:, the two bytes following the initial escape sequence specify the remaining length in bytes, coded in base-128 using bytes 1670:. Each registration receives a unique escape sequence, and a unique registry entry number to identify it. For example, the 9052: 4547:

standard, first published in 2000, defines an updated version of ISO-2022-JP, without the ISO-2022-JP-2 extensions, named

3959:, but stipulates that the escape sequences should not be changed by systems simply relaying messages such as e-mails. The 14623: 14194: 13524: 13321: 8111: 7648: 6415: 1817: 250: 9883: 9878: 9086: 5642:

Because of its escape sequences, it is possible to construct attack byte sequences in which a malicious string (such as

321:

ISO 2022 specifies a general structure which character encodings can conform to, dedicating particular ranges of bytes (

12645: 11924: 11435: 11238: 9982: 8745: 5639:, and switching from or to other charsets, as supported by ISO/IEC 2022, is typically unnecessary in Unicode documents. 5617:

in multiple ways, meaning that two visually identical and equivalent strings can not be reliably compared for equality.

5235:

CSI sequence being used for bidirectional text control. It is an 8-bit code using G0 and G1 for GL and GR, and follows

4160:

ISO-2022-JP with the ISO-2022-JP-2 representation of JIS X 0212, but not the other extensions, was subsequently dubbed

1793: 1654:

The ISO/IEC 2022 / ECMA-35 standard permits, but discourages, invoking G1, G2 or G3 in both GL and GR simultaneously.

889:

Control functions from some sets may make use of further bytes following the escape sequence proper. For example, the

460:), and include additional characters for a most significant bit of 1 (i.e. bytes 0x80–FF). Some of these, such as the 13721: 12745: 11480: 11096: 11091: 10594: 10425: 9972: 9937: 9862: 9825: 6509:, pp. 19–20, Chapter 1 ("CJKV Information Processing Overview"), section "What are Row-Cell and Plane-Row-Cell?" 5186:

defined an ISO 2022 profile named Compound Text as an interchange format in 1989. This uses only four control codes:

4617: 4071: 886:

bytes in the range 0x30–0x3F are reserved for unregistered private uses defined by prior agreement between parties.

14285: 13457: 13301: 10514: 9109:

ISO/IEC 2375:2003: Information technology — Procedure for registration of escape sequences and coded character sets

8857:"(UNSUBMITTED DRAFT) No U+FFFD Generation for Zero-Length ASCII-State Content between ISO-2022-JP Escape Sequences" 8760: 6218: 8142:, pp. 236–238, Chapter 4 ("Encoding Methods"), section "The predecessor of ISO-2022-JP encoding—JIS encoding" 2481: 11732: 11667: 11421: 11401: 4765:

graphical sets as being permitted, but conditional on their being assigned registered ISO 2022 escape sequences:

3879: 2679: 8802: 15383: 14616: 14380: 14375: 14134: 14082: 12182: 12015: 11485: 10078: 5971: 5883: 5801: 3987:

for JIS X 0208 when encoding. The RFC also notes that some past systems had made erroneous use of the sequence

669:

subset of the ISO/IEC 2022 system. In particular, 7-bit encoding systems using ISO/IEC 2022 mechanisms include

8913: 8005: 6117: 4078:. Microsoft's code page for JIS X 0201-based ISO 2022 with single-byte katakana via Shift Out and Shift In is 15143: 14673: 14174: 13504: 13017: 12665: 12187: 11599: 11570: 11220: 8119: 7636: 5845: 5763: 5091:

includes characters represented by up to three bytes (i.e. SS3 plus two bytes) whereas a single character in

4036: 4020: 2930: 2018: 1977: 1715:

ISO Registration Number 177//CHARSET ISO/IEC 10646-1:1993 UCS-4 with implementation level 3//ESC 2/5 2/15 4/6

1687: 1347: 1304: 984: 557: 77: 2880:

Also note that C0 and C1 control character sets are independent; the C0 control character set designated by

1828:); however, a manner for transmitting DRCS fonts is defined within some telecommunication protocols such as 12025: 11662: 11550: 11510: 9930: 8953: 312: 945:

and carriage return control characters as means of combining otherwise spacing characters, as well as the

629:

An infrastructure of multiple character sets with particular structures which may be included in a single

525:

mechanisms to switch between character sets are often given names starting with "ISO-2022-", most notably

408:), and does not provide good support for languages which use additional letters, or which use a different 14519: 13997: 12294: 12206: 11904: 11515: 11445: 11431: 11416: 11320: 11233: 11205: 11171: 9082: 1867:

is appropriate, provided that each byte in the sequence is padded to the code unit size of the encoding.

9888: 6185: 15518: 15058: 15053: 14755: 14683: 14179: 14087: 14037: 13796: 13129: 13124: 12523: 12145: 11878: 11823: 11744: 11525: 11181: 11176: 10529: 1346:

The codes shown in the table below are the most common encodings of these control codes, conforming to

1327:

An 8-bit code may have GR codes specifying G1 characters, i.e. with its corresponding 7-bit code using

728: 553: 11520: 2873:, and so on; the final bytes must be interpreted in context. (Indeed, without any intermediate bytes, 14445: 14390: 14169: 14154: 13412: 12832: 12328: 12050: 11585: 11540: 11376: 10925: 10629: 10574: 10539: 8082: 5569: 5209: 4834:, they could not be given this treatment due to being much more frequently used in deployed content. 4555:. In addition to the basic ISO-2022-JP designation codes, the following designations are recognized: 723:

The escape sequences for switching to particular character sets or encodings are registered with the

492: 346: 9894: 9216: 8655: 8426: 8400: 8374: 8348: 8218: 4019:

Kana set (1 byte per character) is not part of the ISO-2022-JP profile, but is also sometimes used.

942: 796:

ISO/IEC 2022 coding specifies a two-layer mapping between character codes and displayed characters.

744: 15408: 14493: 14400: 14189: 14164: 13376: 13371: 12232: 11100: 10609: 10589: 10584: 10524: 10519: 10028: 9356:

ISO-IR-36: The set of control characters of ISO 646, with IS4 replaced by Single Shift for G2 (SS2)

9198: 8856: 8322: 8296: 8270: 8244: 5997: 5909: 5827: 5752: 1694: 1632: 906: 401: 377: 97: 17: 11475: 4896:

Earlier editions of the standard permitted non-ASCII assignments in the G0 set, provided that the

15513: 15508: 15048: 14047: 13589: 13579: 13574: 13149: 13134: 13074: 12508: 12503: 12463: 11950: 11934: 11861: 11856: 11818: 11789: 11754: 11186: 10920: 10619: 10504: 8609: 7944: 5699: 4048: 634: 549: 496: 326: 4936:

the G1 set. However, use from other sets is noted as having been permitted in earlier editions.

2904:

The standard also defines a way to specify coding systems that do not follow its own structure.

1027:. Other single control functions may be registered to type "3Ft" escape sequences (in the range 14597: 14365: 14355: 13484: 12902: 12483: 12287: 12269: 11545: 11535: 11391: 11381: 10915: 10624: 10069: 10056: 9992: 9603:

ISO-IR-195: UCS Transformation Format (UTF-16), implementation level 3, without standard return

9424: 9385: 9350: 9255: 9200:

ISO-IR: ISO/IEC International Register of Coded Character Sets To Be Used With Escape Sequences

7902: 7028: 5613:

the previous escape sequence before the bytes following the escape sequence can be interpreted.

5534:

For specifying encodings by labels, X11 Compound Text defines five private-use DOCS sequences:

5220: 894: 9582:

ISO-IR-192: UCS Transformation Format (UTF-8), implementation level 3, without standard return

8528: 7426:, p. 10, chapter 2.2 ("94-Character graphic character set with second Intermediate byte") 946: 754: 345:. It also specifies a syntax for escape sequences, multiple-byte sequences beginning with the 15188: 15078: 14639: 13786: 13296: 12518: 12488: 12381: 12371: 12332: 12324: 12135: 12130: 12103: 11722: 11560: 11495: 11371: 10910: 10064: 7449: 5663: 5647: 4822: 4000: 3828: 1829: 10940: 6385:, pp. 253–255, Chapter 4 ("Encoding Methods"), section "EUC versus ISO-2022 encodings". 15456: 15423: 15288: 14857: 14544: 14450: 14184: 14159: 14002: 13843: 13594: 13281: 13084: 12957: 12740: 12140: 12055: 11883: 11555: 11315: 10935: 5667: 5643: 4826: 3836: 3804: 1801: 845: 587: 453: 436:

or letters absent from the ISO Basic Latin alphabet, have historically been represented on

8: 15388: 14385: 12065: 12060: 11838: 11465: 10950: 10835: 10825: 10820: 6193: 6009: 5921: 5839: 5671: 4656: 2849:

bytes is independent for the different types. The 94-character graphic set designated by

805: 514: 365: 8454: 7924: 6101:

byte is not used by the current edition of the standard. However, it is still listed by

1778:

byte range. This is currently only used with 94-character sets, where codes of the form

905:

Each of the four working sets G0 through G3 may be a 94-character set or a 94-character

15363: 15343: 14330: 14265: 12605: 12196: 11991: 11919: 11767: 11580: 11575: 11500: 10499: 10473: 9997: 9953: 9908:

History of Character Codes in North America, Europe, and East Asia from 1999, rev. 2004

9618: 9597: 9576: 9520: 9428: 9389: 9184: 9166: 9152: 9135: 9121: 9103: 9065: 9048: 9031: 9014: 8997: 8980: 6222: 5724: 5655: 5042: 5030: 5024: 4866: 4648: 3843: 1675: 1640: 1024: 690: 630: 500: 376:) so as to use multiple in a single document, effectively combining them into a single 296: 292: 237: 101: 65: 8887: 8803:"DICOM PS3.2 2016d - Conformance; D.6.2 Character Sets; D.6 Support of Character Sets" 8700: 1015:

Additional control functions are assigned to "type Fs" escape sequences (in the range

13159: 11909: 11848: 11828: 11490: 11470: 11450: 11078: 10554: 10534: 10046: 9858: 9854: 9847: 9821: 9817: 9541: 9505:

ISO-IR-149: Korean Graphic Character Set for Information Interchange (KS C 5601:1987)

9449: 9410: 9371: 9276: 9230: 9139: 7053: 5988: 5900: 5818: 5743: 5034: 4837:

In April 2024, a security flaw was found in the implementation of ISO-2022-CN-EXT in

1788:

As with other escape sequence types, the range 0x30–0x3F is reserved for private-use

1312: 647: 605: 480: 437: 358: 342: 15013: 13893: 13634: 12962: 12279: 12070: 12005: 11866: 11440: 11406: 11116: 10945: 9788: 9763: 9734: 9707: 9680: 7402: 5927: 4841:, which lead to recommendations to disable the encoding entirely on Linux systems. 4762: 1864: 1664:

ISO International register of coded character sets to be used with escape sequences

836: 832: 600:

ISO 2022 escape sequences do, however, exist for switching to and from UTF-8 as a "

590:

set and unset within the coded representation for a single code point (e.g. UTF-1,

476: 405: 11959: 7847:, p. 20, chapter 12.5 ("Identification of the coding system of ISO/IEC 2022") 6050:

encoding, use additional escapes of this form for non-ISO-2022-compliant purposes.

15243: 14503: 14224: 14129: 13883: 13811: 13806: 13801: 13286: 13249: 13244: 13239: 13234: 13229: 13224: 13219: 12020: 11914: 11833: 10564: 10559: 10549: 10494: 10179: 10169: 10164: 10159: 10154: 10149: 10144: 9901: 8955:

ARIB STD-B24: Data Coding and Transmission Specification for Digital Broadcasting

8514: 8175:"PQ02042: New Function to Provide C/370 iconv() Support for Japanese ISO-2022-JP" 8174: 5951: 5863: 5781: 5602:

languages with their associated character variants in a single document and font.

5595: 5038: 3800: 840: 797: 484: 425: 9487:

ISO-IR-140: The C0 Set of Control Characters of ISO 646, with EM replaced by SS2

8040: 7966: 4612:

is defined in RFC 1557, dated 1993. It encodes ASCII and the Korean double-byte

575:

Representing all characters, including control codes, with multiple bytes (e.g.

13791: 13539: 13351: 13214: 13204: 13199: 13194: 13189: 13184: 13179: 13174: 13169: 12538: 12528: 12237: 11366: 11361: 11351: 11346: 11341: 11336: 11300: 11295: 11288: 11283: 11278: 11273: 11268: 11263: 11258: 11253: 11248: 11243: 11111: 11068: 11063: 11058: 11053: 11048: 11043: 11038: 11033: 11028: 11023: 11018: 11013: 11008: 11003: 10998: 10905: 10900: 10895: 10890: 10885: 10880: 10875: 10870: 10865: 10860: 10855: 10850: 10634: 10219: 10139: 10134: 10129: 10124: 10119: 10114: 10109: 10104: 10099: 9967: 9895:

International Register of Coded Character Sets to be Used with Escape Sequences

8888:"935453 - Gather telemetry about HZ and other encodings we might try to remove" 6497:, pp. 228–234, Chapter 4 ("Encoding Methods"), section "ISO-2022 encoding" 6190:

MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media

5709: 5704: 5599: 5188: 4151: 4139: 4027:(which also incorporates JIS X 0212 as described below, completing coverage of 3832: 3796: 3462:

C1 controls in CR region in 8-bit environments, as escape sequences otherwise.

488: 449: 409: 10614: 9071:

ECMA-144: 8-Bit Single-Byte Coded Graphic Character sets: Latin Alphabet No. 6

7640: 4704:

The ISO-2022-CN-EXT profile permits the following additional sets and planes.

3803:

as of 2004. (This support has been reduced in later versions to avoid certain

3408:

G0 in GL, G1 in GR if 8-bit, no locking shifts unless in a 7-bit environment.

640:

A format for encoding these sets, assuming that 8 bits are available per byte,

633:

system, including multiple graphical character sets and multiple sets of both

15502: 15466: 15461: 15451: 15446: 15441: 15433: 15428: 15418: 15403: 15398: 15353: 15338: 15333: 15328: 15318: 15308: 15298: 15293: 15273: 15268: 15258: 15233: 15223: 15213: 15178: 15173: 15163: 15158: 15148: 15123: 15118: 14579: 14554: 14539: 14475: 14470: 14465: 14460: 14455: 14300: 14245: 14214: 14204: 14067: 14057: 14027: 14022: 13972: 13952: 13930: 13915: 13868: 13833: 13776: 13771: 13761: 13639: 13584: 13559: 13554: 13534: 13407: 12947: 12386: 12356: 12211: 11686: 11106: 10993: 10988: 10983: 10978: 10973: 10968: 10845: 10840: 10830: 10815: 10810: 10805: 10800: 10795: 10790: 10785: 10780: 10775: 10770: 10765: 10760: 10755: 10750: 10745: 10740: 10735: 10730: 10725: 10720: 10715: 10710: 10705: 10700: 10695: 10690: 10685: 10680: 10675: 10670: 10665: 10660: 10655: 10650: 10569: 10544: 10509: 10468: 10214: 4943: 4616:, previously named KS C 5601-1987. Unlike ISO-2022-JP-2, it makes use of the 3294: 3058: 1860: 1561:

GL or GR (see below) encodes G3 for the immediately following character only

1520:

GL or GR (see below) encodes G2 for the immediately following character only

922: 465: 421: 338: 218: 181: 163: 59: 6788:, p. 5, chapter 7 ("Specification of the characters of the 8-bit code") 1835:

There are also three special cases for multi-byte codes. The code sequences

15413: 15393: 15113: 15088: 15073: 15068: 15063: 15043: 15038: 15033: 15028: 15023: 15018: 15008: 15003: 14698: 14440: 14410: 14270: 13614: 13609: 13472: 13467: 13462: 13381: 13326: 13276: 13209: 13164: 13139: 13069: 13064: 13059: 13054: 13049: 13007: 12972: 12882: 12877: 12513: 12161: 11706: 11701: 11696: 11691: 11426: 11166: 11161: 11156: 11151: 11146: 11141: 11136: 11131: 11126: 11121: 10604: 10599: 10579: 10463: 10088: 9222: 9172:

ISO/IEC 10646: Information technology — Universal Coded Character Set (UCS)

8918:

Unicode Technical Report #36: Unicode Security Considerations (revision 15)

6753: 5183: 4939: 4870: 4098: 3847: 3597: 3575: 3553: 3318: 3290: 1636: 1362: 965: 961: 686: 682: 674: 429: 413: 350: 232: 159: 12035: 9107: 6366:, pp. 242–245, Chapter 4 ("Encoding Methods"), section "EUC encoding" 5666:("�") to prevent them from being used to mask malicious sequences such as 4861:

A subset of ISO 2022 applied to 8-bit single-byte encodings is defined by

863:, where the ESC character is followed by zero or more intermediate bytes ( 564:

generally deviate from the ISO 2022 structure in various ways, including:

468:

do not, usually due to not reserving the bytes 0x80–9F for control codes.

412:

altogether. Other writing systems with relatively few characters, such as

14988: 14780: 14750: 14743: 14738: 14415: 14112: 14107: 14102: 13686: 13603: 12575: 12125: 10021: 10004: 9748:

Zhu, HF.; Hu, DY.; Wang, ZG.; Kao, TC.; Chang, WCH.; Crispin, M. (1996).

7573:, pp. 19–20, chapter 12.4 ("Identification of control function set") 5689: 5075:

G1 is used for a 94x94 coded character set represented in two bytes. The

4924: 4909: 4905: 4897: 4886: 4070:

and allow use of JIS X 0201 kana from G1 without escape sequences, using

3883: 3823:, legacy content in ISO-2022-JP remains sufficiently widespread that the 2836: 1876:

bytes and the designation or other function which they perform is below.

957: 809: 750: 670: 457: 322: 213: 208: 203: 154: 7813:, pp. 18–19, chapter 12.1 ("Purpose and context of identification") 7384: 3850:

encodings also follow ISO 2022, in a subset stipulated in ISO/IEC 4873.

2865:. And neither of those is related to the 94-character set designated by 1703:

ISO 646-1983//CHARSET International Reference Version (IRV)//ESC 2/5 4/0

956:

Use of the backspace and carriage return in this manner is permitted by

281:

Information technology—Character code structure and extension techniques

15358: 15283: 15198: 15138: 14405: 14310: 14017: 13992: 13756: 13711: 13447: 13104: 12917: 12810: 12805: 12800: 12760: 12735: 12610: 12366: 12216: 12200: 12192: 11871: 11779: 11632: 11310: 10405: 10375: 10370: 10365: 10360: 10325: 10209: 10204: 10194: 10189: 9987: 9977: 9916: 6219:"ECMA-35: Character code structure and extension techniques (web page)" 5694: 5565: 5509: 5471: 5453: 5435: 5417: 5399: 5381: 5363: 5345: 5327: 5289: 5236: 5057: 4917: 4818: 4712: 4593: 4583: 4573: 4563: 4544: 4129: 4067: 4016: 3924: 3914: 3904: 3874:. It was introduced for use on the JUNET network and later codified in 3076:

formats of UTF-16 and UTF-32 are designated by their escape sequences.

3073: 3069: 2795: 2754: 2597: 2256: 2215: 1679: 1336: 926: 765: 545: 537: 472: 373: 139: 134: 129: 124: 11812: 9922: 9776: 9750: 9722: 9695: 9668: 9643: 9622: 9601: 9580: 9559: 9524: 9503: 9485: 9467: 9432: 9393: 9354: 9333: 9312: 9291: 9259: 7801:, p. 19, chapter 12.2 ("Identification of a UCS encoding scheme") 7772:, p. 21, chapter 2.8.2 ("Coding systems without Standard return") 7032: 4794:(0x28) designates a 94-character set to the G0 character set, whereas 3390:

G0 in GL, G1 in GR, no locking shifts, requires an 8-bit environment.

15471: 15248: 15183: 14972: 14967: 14962: 14957: 14952: 14942: 14932: 14927: 14917: 14912: 14907: 14902: 14892: 14887: 14882: 14867: 14862: 14852: 14847: 14842: 14832: 14827: 14822: 14817: 14812: 14807: 14802: 14797: 14775: 14770: 14760: 14733: 14728: 14718: 14713: 14708: 14703: 14693: 14688: 14678: 14663: 14658: 14653: 14574: 14569: 14564: 14559: 14534: 14524: 14485: 14435: 14430: 14425: 14420: 14325: 14320: 14315: 14305: 14295: 14280: 14260: 14255: 14250: 14199: 14144: 14139: 14119: 14097: 14077: 14032: 14012: 13967: 13962: 13957: 13925: 13888: 13878: 13863: 13858: 13853: 13838: 13823: 13818: 13746: 13741: 13736: 13716: 13706: 13701: 13696: 13681: 13676: 13624: 13619: 13599: 13569: 13544: 13529: 13499: 13452: 13442: 13422: 13417: 13402: 13397: 13311: 13032: 13027: 12922: 12568: 12563: 12558: 12553: 12548: 12456: 12451: 12446: 12441: 12177: 11759: 11737: 11642: 11455: 10484: 10415: 10395: 10390: 10315: 10310: 9912: 9842: 9809: 9793: 9767: 9739: 9712: 9685: 5526: 5198: 5061: 5053: 4853:

Relationship between ECMA-43 (ISO/IEC 4873) editions and levels, and

4687: 4652: 4075: 3992: 2133: 2064: 1430: 1332: 694: 433: 149: 144: 31: 9234: 8686:, pp. 10–11, chapter 10 ("Identification of version and level") 5048:

The code assigned to the G0 set is ASCII, or the country's national

4849: 1816:

byte (for a double-byte set) is 0x20 (space), the set denoted is a "

1697:

to identify character sets used for numeric character references in

1158:

Used when interacting with an outer coding / representation system,

714: 15323: 14897: 14877: 14837: 14792: 14723: 14668: 14209: 13987: 13691: 13519: 13356: 13346: 13331: 13306: 13291: 13266: 13261: 13144: 13119: 13114: 13099: 13094: 13089: 13079: 13044: 13039: 13022: 13002: 12997: 12992: 12987: 12982: 12977: 12967: 12952: 12942: 12937: 12927: 12912: 12907: 12897: 12892: 12887: 12872: 12867: 12862: 12857: 12852: 12837: 12822: 12795: 12790: 12785: 12780: 12775: 12770: 12765: 12755: 12750: 12730: 12725: 12715: 12710: 12700: 12695: 12685: 12680: 12675: 12650: 12640: 12533: 12436: 12431: 12426: 12421: 12416: 12411: 12406: 12401: 12396: 12097: 11929: 11784: 11749: 11727: 11637: 11460: 10400: 10385: 10345: 10340: 10335: 10320: 10279: 10274: 10269: 10264: 10259: 10254: 10051: 10041: 10037: 10011: 9904:, a full list of assigned character sets and their escape sequences 9624:

ISO-IR-196: UCS Transformation Format (UTF-8), with standard return

7732:, p. 20, chapter 2.8.1 ("Coding systems with Standard return") 6812:, p. 3, chapter 6 ("Specification of the coded character set") 6800:, p. 3, chapter 6 ("Specification of the coded character set") 6043: 5714: 5684: 5069: 5065: 4769: 4031:); this is close in both name and structure to an encoding denoted 3875: 3812: 2908: 2893: 2638: 1936: 1804:). However, in a graphical set designation sequence, if the second 1693:

ISO-IR registered escape sequences are also used encapsulated in a

1403: 1358: 1354: 1340: 1328: 1074:

Disables some or all of the manual input facilities of the device.

918: 890: 592: 461: 417: 389: 354: 112: 6042:) only, for historical reasons. Some implementations, such as the 3890:. It starts in ASCII and includes the following escape sequences: 1657: 15348: 15313: 15303: 14872: 14785: 14498: 14290: 14275: 14072: 14062: 14052: 13828: 13644: 13489: 13477: 12635: 12630: 12625: 12620: 12615: 12600: 12595: 12590: 12585: 12580: 12543: 12498: 12493: 12478: 12473: 12468: 11799: 11595: 11505: 11386: 10960: 10330: 10305: 10295: 10033: 9645:

ISO-IR-208: Ogham coded character set for information interchange

7516:, p. 103, chapter 14 ("Dynamically Re-definable Characters") 5632: 5492: 5049: 4675: 4644: 4613: 4119: 4109: 3996: 3991:

to switch away from JIS X 0208, which is actually registered for

3726:

LS3R used in 8-bit environments, LS3 used in 7-bit environments.

3690:

LS2R used in 8-bit environments, LS2 used in 7-bit environments.

3062: 2174: 1706: 702: 697:

languages. More specialised applications of ISO 2022 include the

541: 505: 381: 334: 330: 185: 119: 83: 14608: 9696:"RFC 1554: ISO-2022-JP-2: Multilingual Extension of ISO-2022-JP" 7389:

SP: an SGML System Conforming to International Standard ISO 8879

3654:

LS1R used in 8-bit environments, SO used in 7-bit environments.

3372:

G0 and G1 invoked to GL by locking shifts, GR absent or unused.

2857:

is not related in any way to the 96-character set designated by

909:. Additionally, G1 through G3 may be a 96- or 96-character set. 15378: 15373: 15368: 15278: 15218: 15208: 15203: 15193: 15153: 15103: 14360: 14345: 14340: 14335: 14007: 13982: 13910: 13766: 13751: 13731: 13726: 13671: 13664: 13659: 13654: 13549: 13514: 13361: 13012: 12827: 12391: 12118: 12092: 11804: 11794: 11772: 11652: 11627: 11622: 11305: 11196: 11086: 10445: 10435: 10420: 10237: 9240: 8123: 8083:"codecs — Codec registry and base classes § Standard Encodings" 7217: 7045: 6580: 6547: 6102: 6060: 5935: 5853: 5771: 5307: 5092: 5088: 5084: 5076: 4831: 4810: 4028: 3960: 3871: 3824: 3516:

Uses a 7-bit code, even if an eighth bit is available for use.

3233: 3166: 1797: 1705:

can be used to identify the International Reference Version of

698: 678: 580: 576: 530: 385: 6186:"Technique 2: Using standard alternate graphic character sets" 4817:

maps ISO-2022-KR, ISO-2022-CN and ISO-2022-CN-EXT (as well as

4667:, to which the RFC provides a correspondence in an appendix): 15228: 15108: 15098: 15093: 15083: 14993: 14922: 14395: 14370: 14092: 13977: 13848: 13629: 13494: 13366: 13341: 13336: 13316: 12690: 12660: 12655: 12376: 12361: 12351: 12346: 12113: 12108: 11899: 11617: 11612: 11607: 11224: 10930: 10440: 10380: 10242: 10016: 9777:"RFC 2237: Japanese Character Encoding for Internet Messages" 9669:"RFC 1468: Japanese Character Encoding for Internet Messages" 9555: 7936: 7934: 7932: 7114: 6047: 5961: 5873: 5791: 5651: 5636: 5628: 5621: 5272: 4838: 4814: 3964: 3943:

The RFC notes that some existing systems did not distinguish

3820: 3276: 3119: 3099: 2916: 2912: 2889: 2556: 2443: 1671: 1308: 930: 804:

Encoding byte values ("bit combinations") are often given in

774: 758: 609: 569: 561: 369: 318:. Originating in 1971, it was most recently revised in 1994. 9751:"RFC 1922: Chinese Character Encoding for Internet Messages" 8116:

DIGITAL UNIX Technical Reference for Using Japanese Features

4821:) to the "replacement" decoder, which maps all input to the 4755:

to switch to CNS 11643-1992 Plane 7 (2 bytes per character)

4747:

to switch to CNS 11643-1992 Plane 6 (2 bytes per character)

4739:

to switch to CNS 11643-1992 Plane 5 (2 bytes per character)

4731:

to switch to CNS 11643-1992 Plane 4 (2 bytes per character)

4723:

to switch to CNS 11643-1992 Plane 3 (2 bytes per character)

4698:

to switch to CNS 11643-1992 Plane 2 (2 bytes per character)

757:'s unregistered G2 does, as does the similarly unregistered 681:. 8-bit encoding systems conforming to ISO/IEC 2022 include 15253: 15168: 14765: 14042: 13905: 13898: 13564: 13509: 13109: 12720: 12258: 11210: 10300: 9784: 9759: 9730: 9723:"RFC 1557: Korean Character Encoding for Internet Messages" 9703: 9676: 9095: 8605: 5719: 4873:

defines 8-bit codes for ISO/IEC 4873 (or ECMA-43) level 1.

4664: 4066:

build directly on the 7-bit and 8-bit encodings defined by

3030:

selects an 8-bit code; there is no standard way to return.

1725:

Escape sequences to designate character sets take the form

1710: 1698: 518: 445: 304: 71: 9561:

ISO-IR-164: Hebrew Supplementary Set of Graphic Characters

9293:

ISO-IR-7: NATS Control set for newspaper text transmission

9003:

ECMA-35: Character Code Structure and Extension Techniques

8656:"8. Code Extension, ISO 2022 and 2375, ISO 4873 and 10367" 8644:, pp. 10, chapter 9.2 ("Unique coding of characters") 8580:, p. 11, chapter 10.3 ("Identification of a version") 7929: 4913: 4901: 4624:

once at the start of a line to designate KS X 1001 to G1.

3791: 2432: 1159: 749:

To represent large character sets, ISO/IEC 2022 builds on

601: 14947: 14529: 14219: 13271: 12076: 11677: 9176: 9113: 8705: 8696: 8422: 8396: 8370: 8344: 8318: 8292: 8266: 8240: 8214: 8178: 7898: 7410: 5243:

ISO 2022 designation sequences used in X11 Compound Text

4876:

ISO/IEC 4873 / ECMA-43 defines three levels of encoding:

4172: 3870:

is a widely used encoding for Japanese, in particular in

3816: 3426:

Shift functions preserved during 7-bit/8-bit conversion.

3317:

standard, as is using additional announcements on top of

3057:

Of particular interest are the sequences which switch to

3024:

Designate other coding system ("without standard return")

983:

If codes from the C0 set of ISO 6429 / ECMA-48, i.e. the

856:

Sequences using the ESC (escape) character take the form

441: 7448:

Mascheck, Sven; Le Breton, Stefan; Hamilton, Richard L.

7222: 7220: 2899: 9314:

ISO-IR-14: The Japanese Roman graphic set of characters

8942: 5095:

can take up to four bytes (i.e. SS2 plus three bytes).

4142:

high part, Extended Latin 1 set (1 byte per character)

1137:

Resets the device to its state after being powered on.

380:

encoding (a feature less important since the advent of

9660: 9335:

ISO-IR-26: Control set for newspaper text transmission

9261:

ISO-IR-1: The set of control characters of the ISO 646

9037:

ECMA-43: 8-Bit Coded Character Set Structure and Rules

9020:

ECMA-43: 8-Bit Coded Character Set Structure and Rules

7958: 7956: 7954: 7952: 6994:, p. 19, chapter 2.7 ("Single control functions") 6824:, p. 19, annex C ("Composite graphic characters") 6002: 5914: 5832: 5757: 5239:

in its initial state. The following F-bytes are used:

4596:

Plane 1 (2 bytes per character, ISO-2022-JP-2004 only)

2993:

Designate other coding system ("with standard return")

715:§ Registration of graphical and control code sets 677:), which has primarily been used in Japanese-language 27:

Higher-level 7-bit and 8-bit character encoding system

9891:, equivalent to ISO/IEC 2022 and freely downloadable. 7447: 4761:

The ISO-2022-CN-EXT profile further lists additional

1924:

Specifies code features used, e.g. working sets (see

1741:) bytes are from the range 0x20–0x2F, and the final ( 851: 768:

of each character is normally specified in so-called

12309: 9469:

ISO-IR-106: Teletex Primary Set of Control Functions

9229: 9134: 8507: 8036: 7962: 7940: 7920: 6797: 6319: 5975: 5887: 5805: 5029:

Extended Unix Code (EUC) is an 8-bit variable-width

4806:(0x29–0x2B) designates to the G1–G3 character sets. 11989: 9054:

ECMA-48: Control Functions for Coded Character Sets

8986:

ECMA-35: Extension of the 7-bit Coded Character Set

8701:"Character Data Representation Architecture (CDRA)" 8419: