Indian Script Code for Information Interchange (ISCII) is a coding scheme for representing various writing systems of India. It encodes the main Indic scripts and a Roman transliteration. The supported scripts are: Bengali–Assamese, Devanagari, Gujarati, Gurmukhi, Kannada, Malayalam, Odia, Tamil, and Telugu. ISCII does not encode the writing systems of India that are based on Persian, but its writing system switching codes nonetheless provide for Kashmiri, Sindhi, Urdu, Persian, Pashto and Arabic. The Persian-based writing systems were subsequently encoded in the PASCII encoding.
ISCII has not been widely used outside certain government institutions, although a variant without the mechanism was used on classic Mac OS, Mac OS Devanagari, and it has now been rendered largely obsolete by Unicode. Unicode uses a separate block for each Indic writing system, and largely preserves the ISCII layout within each block.
Background
The Brahmi-derived writing systems have similar structure. So ISCII encodes letters with the same phonetic value at the same code point, overlaying the various scripts. For example, the ISCII codes 0xB3 0xDB represent [ki]. This will be rendered as കി in Malayalam, कि in Devanagari, as ਕਿ in Gurmukhi, and as கி in Tamil. The writing system can be selected in rich text by markup or in plain text by means of the code described below.
One motivation for the use of a single encoding is the idea that it will allow easy transliteration from one writing system to another. However, there are enough incompatibilities that this is not really a practical idea.
ISCII is an 8-bit encoding. The lower 128 code points are plain ASCII, the upper 128 code points are ISCII-specific. In addition to the code points representing characters, ISCII makes use of a code point with mnemonic that indicates that the following byte contains one of two kinds of information. One set of values changes the writing system until the next writing system indicator or end-of-line. Another set of values select display modes such as bold and italic. ISCII does not provide a means of indicating the default writing system.
Code page layout
The following table shows the character set for Devanagari. The code sets for Assamese, Bengali, Gujarati, Gurmukhi, Kannada, Malayalam, Oriya, Tamil, and Telugu are similar, with each Devanagari form replaced by the equivalent form in each writing system. Each character is shown with its decimal code and its Unicode equivalent.
Special code points
INV character—code point D9 (217) The INV (invisible consonant) character is used as a pseudo-consonant to display combining elements in isolation. For example, क (ka) + ् (halant) + INV = क् (half ka). The Unicode equivalent is (). However, as noted below, the ISCII halant character can be doubled or combined with the ISCII nukta to achieve effects created by or ZWJ in Unicode. For this reason, Apple maps the ISCII INV character to the Unicode , so as to guarantee round-tripping. ATR character—code point EF (239) The ATR (attribute) character followed by a byte code is used to switch to a different font attribute (such as bold) or to a different ISCII or PASCII language (such as Bengali), up to the next ATR sequence or the end of the line. This has no direct Unicode equivalent, as font attributes are not part of Unicode, and each script has a distinct set of code points. + Presentational attributes ATR + byteMnemonicFormatting option0x30BLDBold0x31ITAItalics0x32ULUnderlining0x33EXPExpanded0x34HLTHighlight0x35OTLOutline0x36SHDShadow0x37TOPTop half of character (used with LOW to create double-height characters)0x38LOWBottom half of character (used with TOP to create double-height characters)0x39DBLEntire row double-width and double-height + Shifts to ISCII scripts ATR + byteMnemonicISCII script0x40DEFDefault script (i.e. the script which will be switched back to after a line break)0x41RMNRomanised transliteration0x42DEVDevanagari0x43BNGBengali script0x44TMLTamil script0x45TLGTelugu script0x46ASMAssamese script0x47ORIOdia script0x48KNDKannada script0x49MLMMalayalam script0x4AGJRGujarati script0x4BPNJGurmukhī + Shifts to PASCIIATR + byteMnemonicPASCII locale0x71ARBArabic alphabet0x72PESPersian alphabet0x73URDUrdu alphabet0x74SNDSindhi alphabet0x75KSMKashmiri alphabet0x76PSTPashto alphabet EXT character—code point F0 (240) The EXT (extensions for Vedic) character followed by a byte code indicates a Vedic accent. This has no direct Unicode equivalent, as Vedic accents are assigned to distinct code points. Halant character ्—code point E8 (232) The halant character removes the implicit vowel from a consonant and is used between consonants to represent conjunct consonants. For example, क (ka) + ् (halant) + त (ta) = क्त (kta). The sequence ् (halant) + ् (halant) displays a conjunct with an explicit halant, for example क (ka) + ् (halant) + ् (halant) + त (ta) = क्त. The sequence ् (halant) + ़ (nukta) displays a conjunct with half consonants, if available, for example क (ka) + ् (halant) + ़ (nukta) + त (ta) = क्त. + Correspondences between ISCII and Unicode halent/virama behaviour ISCII Unicode single halant E8 halant 094D halant + halant E8 E8 halant + ZWNJ 094D 200C halant + nukta E8 E9 halant + ZWJ 094D 200D Nukta character ़—code point E9 (233) The nukta character after another ISCII character is used for a number of rarer characters which don't exist in the main ISCII set. For example क (ka) + ़ (nukta) = क़ (qa). These characters have precomposed forms in Unicode, as shown in the following table. + Single Unicode characters corresponding to ISCII nukta sequences ISCIIcode point Originalcharacter Characterwith nukta Unicodecode point A1 (161) ँ ॐ 0950 A6 (166) इ ऌ 090C A7 (167) ई ॡ 0961 AA (176) ऋ ॠ 0960 B3 (179) क क़ 0958 B4 (180) ख ख़ 0959 B5 (181) ग ग़ 095A BA (186) ज ज़ 095B BF (191) ड ड़ 095C C0 (192) ढ ढ़ 095D C9 (201) फ फ़ 095E DB (219) ि ॢ 0962 DC (220) ी ॣ 0963 DF (223) ृ ॄ 0944 EA (234) । ऽ 093D
Code pages for ISCII conversion
To convert from Unicode (UTF-8) to an ISCII / ANSI coding, the following code pages may be used:
57002: Devanagari (Hindi, Marathi, Sanskrit, Konkani) 57003: Bengali 57004: Tamil 57005: Telugu 57006: Assamese 57007: Odia 57008: Kannada 57009: Malayalam 57010: Gujarati 57011: Punjabi (Gurmukhi)
Code points for all languages