Definitions

iso-

ISO/IEC 8859-1

ISO 8859-1, more formally cited as ISO/IEC 8859-1 is part 1 of ISO/IEC 8859, a standard character encoding of the Latin alphabet. It is less formally referred to as Latin-1. It was originally developed by the ISO, but later jointly maintained by the ISO and the IEC. The standard, when supplemented with additional character assignments (in the C0 and C1 ranges: 0x00 to 0x1F and 0x7F, and 0x80 to 0x9F), is the basis of two widely-used character maps known as ISO-8859-1 (note the extra hyphen) and Windows-1252.

In June 2004, the ISO/IEC working group responsible for maintaining eight-bit coded character sets disbanded and ceased all maintenance of ISO 8859, including ISO 8859-1, in order to concentrate on the Universal Character Set and Unicode. In computing applications, encodings that provide full UCS support (such as UTF-8 and UTF-16) are finding increasing favor over encodings based on ISO 8859-1.

Coverage

ISO 8859-1 encodes what it refers to as "Latin alphabet no. 1," consisting of 191 characters from the Latin script. This character encoding is used throughout The Americas, Western Europe, Oceania, and much of Africa. It is also commonly used in most standard romanizations of East-Asian languages.

Each character is encoded as a single eight-bit code value. These code values can be used in almost any data interchange system to communicate in the following European languages (with a few exceptions due to missing characters, as noted): Modern languages with complete coverage of their alphabet:

  • Icelandic
  • Irish (new orthography)
  • Italian
  • Kurdish (The Kurdish Unified Alphabet)
  • Latin (basic classical orthography)
  • Luxembourgish (basic classical orthography)
  • Norwegian (Bokmål and Nynorsk)
  • Occitan
  • Languages commonly supported with nearly complete coverage of their alphabet

    • Dutch (missing IJ, ij but these should always be represented as IJ or ij in electronic form)
    • Estonian (missing Š, š, Ž, ž for loan words)
      • Note that Windows-1252 and ISO-8859-15 do contain these
    • French (missing Œ, œ and the very rare Ÿ; they are generally replaced by 'OE' and 'oe' without the normally required ligature, and 'Y' without the diaeresis)
      • Note that Windows-1252 and ISO-8859-15 do contain these
    • Finnish (missing Š, š, Ž, ž for loan words)
      • Note that Windows-1252 and ISO-8859-15 do contain these
    • Welsh (missing Ŵ, ŵ, Ŷ, ŷ)

    Coverage of punctuation signs and apostrophes For some languages listed above the correct typographical quotation marks are missing, for only « », " ", and ' ' are included.

    Also, this encoding does not provide the correct character for the apostrophe, and oriented single high quotation marks, although some texts use the spacing grave accent and spacing acute accent which are both part of ISO 8859-1, instead of the 6-shaped/9-shaped quotations marks or apostrophes (and this works reliably with some font styles where all these characters are displayed as slanted wedge glyphs).

    See also: Alphabets derived from the Latin

    History

    ISO 8859-1 was based on the Multinational Character Set used by Digital Equipment Corporation in the popular VT220 terminal. It was developed within ECMA, the European Computer Manufacturers Association, and published in March 1985 as ECMA-94, by which name it is still sometimes known. The second edition of ECMA-94 (June 1986) also included ISO 8859-2, ISO 8859-3, and ISO 8859-4 as part of the specification

    Relationship to ISO/IEC 8859-15

    Although ISO/IEC 8859-1 has enough characters for most French text, it is missing a few letters that are less common. It is also missing a single-glyph representation for the letter IJ, two Finnish letters used for transcription of some foreign names and in a few loanwords (Š and Ž), typographic quotation marks and dashes, and common symbols such as the euro sign (€) and dagger (†).

    In order to provide some of these characters, ISO/IEC 8859-15 was developed as an update of ISO/IEC 8859-1. This required, however, the removal of some infrequently-used characters from ISO/IEC 8859-1, including fraction symbols and letter-free diacritics: ¤, ¦, ¨, ´, ¸, ¼, ½, and ¾.

    Codepage layout

    Since all 191 characters encoded by ISO/IEC 8859-1 are 'graphic' (ISO's term for characters that are not control codes) and are compatible with most web browsers, they can be shown as glyphs in the following table. Since the space, no-break space, and soft hyphen characters would not normally be visible, they are represented by abbreviations for their names. All other characters are represented literally. Row and column headings indicate the hexadecimal digit combinations to produce the eight-bit code value; e.g., the letter L is at code value 4C.

    007D|}|125}}

    Code values 00–1F, 7F–9F are not assigned to characters by ISO/IEC 8859-1.

    The lower range 20 to 7E (the G0 subset) maps exactly to the same coded G0 subset of the ISO 646 US variant (commonly known as ASCII), whose ISO 2022 standard switch sequence is "ESC (B". The higher range A0 to FF (the G1 subset) maps exactly to the same subset initiated by the ISO 2022 standard switch sequence "ESC . A".

    Related character maps

    The ISO/IEC 8859-1 standard has long been the basis of a number of character maps, also known as character sets, charsets, or code pages, the most popular being ISO-8859-1 (note the extra hyphen) and Windows-1252. Both of these maps are a superset of ISO/IEC 8859-1; they supplement the standard's 191 character assignments by mapping additional characters to at least some portion of the code value ranges 00–1F, 7F, and 80–9F.

    ISO-8859-1

    In 1992, the IANA registered the character map ISO_8859-1:1987, more commonly known by its preferred MIME name of ISO-8859-1 (note the extra hyphen over ISO 8859-1), a superset of ISO 8859-1, for use on the Internet. This map assigns the C0 and C1 control characters to the code values 00–1F, 7F, and 80–9F. It thus provides for 256 characters via every possible 8-bit value.

    ISO-8859-1 is (according to the standards at least) the default encoding of documents delivered via [] with a MIME type beginning with "text/". It is the default encoding of the values of certain descriptive HTTP headers, and is the standard encoding used by the X Window System on most Unix machines in locales which use that character set. It was also the basis of the repertoire of characters allowed in HTML 3.2 documents (HTML 4.0, however, is based on Unicode).

    Escape sequences (from ISO/IEC 6429 or ISO/IEC 2022) are not to be interpreted in documents labeled as ISO-8859-1 encoded. As well as the canonical name and preferred MIME name mentioned above, the following other aliases are registered for ISO-8859-1: ISO_8859-1, ISO-8859-1, iso-ir-100, csISOLatin1, latin1, l1, IBM819, CP819. ISO-8859-1 was also incorporated as the first 256 code points of ISO/IEC 10646 and Unicode.

    Code point Control character Abbreviation
    00 Null NUL
    01 Start Of Heading SOH
    02 Start of Text STX
    03 End of Text ETX
    04 End Of Transmission EOT
    05 Enquiry ENQ
    06 Acknowledge ACK
    07 Bell BEL
    08 Backspace BS
    09 Horizontal Tab HT
    0A Line Feed LF
    0B Vertical Tab VT
    0C Form Feed FF
    0D Carriage Return CR
    0E Shift Out SO
    0F Shift In SI
    10 Data Link Escape DLE
    11 Device Control 1 DC1
    12 Device Control 2 DC2
    13 Device Control 3 DC3
    14 Device Control 4 DC4
    15 Negative Acknowledge NAK
    16 Synchronous idle SYN
    17 End of Transmission Block ETB
    18 Cancel CAN
    19 End of Medium EM
    1A Substitute (character) SUB
    1B Escape character ESC
    1C File separator FS
    1D Group separator GS
    1E Record separator RS
    1F Unit separator US
    7F Delete DEL
     
    Code point Control character Abbreviation
    80 Padding Character PAD
    81 High Octet Preset HOP
    82 Break Permitted Here BPH
    83 No Break Here NBH
    84 Index IND
    85 Next Line NEL
    86 Start of Selected Area SSA
    87 End of Selected Area ESA
    88 Character Tabulation Set HTS
    89 Character Tabulation with Justification HTJ
    8A Line Tabulation Set VTS
    8B Partial Line Forward PLD
    8C Partial Line Backward PLU
    8D Reverse Line Feed RI
    8E Single Shift 2 SS2
    8F Single Shift 3 SS3
    90 Device Control String DCS
    91 Private Use 1 PU1
    92 Private Use 2 PU2
    93 Set Transmit State STS
    94 Cancel Character CCH
    95 Message Waiting MW
    96 Start of Guarded Area SPA
    97 End of Guarded Area EPA
    98 Start of String SOS
    99 Single Graphic Character Introducer SGCI
    9A Single Character Introducer SCI
    9B Control Sequence Introducer CSI
    9C String Terminator ST
    9D Operating System Command OSC
    9E Privacy Message PM
    9F Application Program Command APC

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    Note that most of these control characters are not made for use in portable ISO-8859-1 encoded plain text documents, but only within specific protocols or devices, except a few ones whose behavior are standardized: TAB (09), LF (0A), CR (0D) and NEL (85); all but the first one are used to encode end of lines or to separate paragraphs, and TAB is often considered equivalent to whitespace. However FF (0C) is commonly accepted in some applications interpreting plain-text documents as an additional ignorable whitespace at the beginning of lines, to mark the position of an explicit page break when printing.

    However, some encodings allow using BS (08) to create additional characters by emulating the superposition of multiple characters on printing devices.

    Some ISO standards assign specific functions to some controls (for example in ISO 2022) where SO (0E), SI (0F), DLE (10), ESC (1B) and SS2 (8E) are used to control the encoding of characters after them or to switch between multiple encodings.

    The NUL character (00) is commonly used as a string terminator in some programming languages, or as a filler in database records that must be ignored and is not part of the encoded text. STX (02) and ETX (03) are commonly used for delimiting frames in some transmission protocols. SUB (1A) is also commonly used as a replacement character to mark errors detected in input transmission streams, and it may be rendered graphically. DC1 (11) and DC3 (13) are commonly used in the XON/XOFF protocol for controlling the transmission speed. Finally, EM (19) or EOT (04) may be used as an end-of-file marker in some text file formats.

    The ISO-8859-1/Windows-1252 mixup

    It is very common to mislabel text data with the charset label ISO-8859-1, even though the data are really Windows-1252 encoded. In Windows-1252, codes between 0x80 and 0x9F are used for letters and punctuation, whereas they are control codes in ISO-8859-1. Many web browsers and e-mail clients will interpret ISO-8859-1 control codes as Windows-1252 characters in order to accommodate such mislabeling but it is not a standard behaviour and care should be taken to avoid generating these characters in ISO-8859-1 labeled content.

    HTML 5 requires that documents advertised as ISO-8859-1 actually use the Windows-1252 encoding. If the document uses any character with different meaning in ISO-8859-1 and Windows-1252, that is considered a parse error.

    Similar character sets

    The Apple Macintosh computer introduced a character encoding called Mac Roman, or Mac-Roman, in 1984. It was meant to be suitable for Western European desktop publishing. It is a superset of ASCII, like ISO-8859-1, and has most of the characters that are in ISO-8859-1 but in a totally different arrangement. A later version, registered with IANA as "Macintosh", replaced the generic currency sign ¤ with the euro sign €. The few printable characters that are in ISO 8859-1 but not in this set are often a source of trouble when editing text on websites using older Macintosh browsers (including the last version of Internet Explorer for Mac). However the extra characters that Windows-1252 has in the C1 codepoint range are all supported in MacRoman and except for the few missing ISO-8859-1 characters a Macintosh can send/receive files (and email) that are encoded/marked as ISO-8859-1 (with the C1 Control Characters) and Windows-1252 by remapping the glyph's codepoint numbers.

    DOS had code page 850, which had all printable characters that ISO-8859-1 had (albeit in a totally different arrangement) plus the most widely used graphics characters from code page 437.

    See also

    Notes

    External links

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