Indian Script Code for Information Interchange

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: Assamese, Bengal (Bangla), Devanagari, Gujarati, Gurmukhi, Kannada, Malayalam, Oriya, Tamil, and Telugu. ISCII does not encode the writing systems of India 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 ATR mechanism was used on classic Mac OS,[1] 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 ATR 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 ATR 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.

Codepage 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.

ISCII Devanagari
_0 _1 _2 _3 _4 _5 _6 _7 _8 _9 _A _B _C _D _E _F
0_
0		 NUL
0000		 SOH
0001		 STX
0002		 ETX
0003		 EOT
0004		 ENQ
0005		 ACK
0006		 BEL
0007		 BS
0008		 HT
0009		 LF
000A		 VT
000B		 FF
000C		 CR
000D		 SO
000E		 SI
000F
1_
16		 DLE
0010		 DC1
0011		 DC2
0012		 DC3
0013		 DC4
0014		 NAK
0015		 SYN
0016		 ETB
0017		 CAN
0018		 EM
0019		 SUB
001A		 ESC
001B		 FS
001C		 GS
001D		 RS
001E		 US
001F
2_
32		 SP
0020		 !
0021		 "
0022		 #
0023		 $
0024		 %
0025		 &
0026		 '
0027		 (
0028		 )
0029		 *
002A		 +
002B		 ,
002C		 -
002D		 .
002E		 /
002F
3_
48		 0
0030		 1
0031		 2
0032		 3
0033		 4
0034		 5
0035		 6
0036		 7
0037		 8
0038		 9
0039		 :
003A		 ;
003B		 <
003C		 =
003D		 >
003E		 ?
003F
4_
64		 @
0040		 A
0041		 B
0042		 C
0043		 D
0044		 E
0045		 F
0046		 G
0047		 H
0048		 I
0049		 J
004A		 K
004B		 L
004C		 M
004D		 N
004E		 O
004F
5_
80		 P
0050		 Q
0051		 R
0052		 S
0053		 T
0054		 U
0055		 V
0056		 W
0057		 X
0058		 Y
0059		 Z
005A		 [
005B		 \
005C		 ]
005D		 ^
005E		 _
005F
6_
96		 `
0060		 a
0061		 b
0062		 c
0063		 d
0064		 e
0065		 f
0066		 g
0067		 h
0068		 i
0069		 j
006A		 k
006B		 l
006C		 m
006D		 n
006E		 o
006F
7_
112		 p
0070		 q
0071		 r
0072		 s
0073		 t
0074		 u
0075		 v
0076		 w
0077		 x
0078		 y
0079		 z
007A		 {
007B		 |
007C		 }
007D		 ~
007E		 DEL
007F
8_
128
9_
144
A_
160		 ँ
0901		 ं
0902		 ः
0903		 अ
0905		 आ
0906		 इ
0907		 ई
0908		 उ
0909		 ऊ
090A		 ऋ
090B		 ऎ
090E		 ए
090F		 ऐ
0910		 ऍ
090D		 ऒ
0912
B_
176		 ओ
0913		 औ
0914		 ऑ
0911		 क
0915		 ख
0916		 ग
0917		 घ
0918		 ङ
0919		 च
091A		 छ
091B		 ज
091C		 झ
091D		 ञ
091E		 ट
091F		 ठ
0920		 ड
0921
C_
192		 ढ
0922		 ण
0923		 त
0924		 थ
0925		 द
0926		 ध
0927		 न
0928		 ऩ
0929		 प
092A		 फ
092B		 ब
092C		 भ
092D		 म
092E		 य
092F		 य़
095F		 र
0930
D_
208		 ऱ
0931		 ल
0932		 ळ
0933		 ऴ
0934		 व
0935		 श
0936		 ष
0937		 स
0938		 ह
0939		 INV
 		 ा
093E		 ि
093F		 ी
0940		 ु
0941		 ू
0942		 ृ
0943
E_
224		 ॆ
0946		 े
0947		 ै
0948		 ॅ
0945		 ॊ
094A		 ो
094B		 ौ
094C		 ॉ
0949		 ्
094D		 ़
093C		 ।
0964		 ATR
 
F_
240		 EXT
 		 ०
0966		 १
0967		 २
0968		 ३
0969		 ४
096A		 ५
096B		 ६
096C		 ७
096D		 ८
096E		 ९
096F

  Letter   Number   Punctuation   Symbol   Other   Undefined

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 U+200D ZERO WIDTH JOINER (ZWJ). However, as noted below, the ISCII halant character can be doubled or combined with the ISCII nukta to achieve effects created by ZWNJ or ZWJ in Unicode. For this reason, Apple maps the ISCII INV character to the Unicode left-to-right mark, so as to guarantee round-tripping.[1]
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 option
0x30BLDBold
0x31ITAItalics
0x32ULUnderlining
0x33EXPExpanded
0x34HLTHighlight
0x35OTLOutline
0x36SHDShadow
0x37TOPTop 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 script
0x40DEFDefault script (i.e. the script which will be switched back to after a line break)
0x41RMNRomanised transliteration
0x42DEVDevanagari
0x43BNGBengali script
0x44TMLTamil script
0x45TLGTelugu script
0x46ASMAssamese script
0x47ORIOdia script
0x48KNDKannada script
0x49MLMMalayalam script
0x4AGJRGujarati script
0x4BPNJGurmukhī
Shifts to PASCII
ATR + byteMnemonicPASCII locale
0x71ARBArabic alphabet
0x72PESPersian alphabet
0x73URDUrdu alphabet
0x74SNDSindhi alphabet
0x75KSMKashmiri alphabet
0x76PSTPashto 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
ISCIIUnicode
single halantE8halant094D
halant + halantE8 E8halant + ZWNJ094D 200C
halant + nuktaE8 E9halant + ZWJ094D 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
ISCII
code point		Original
character		Character
with nukta		Unicode
code point
A1 (161)ँॐ0950
A6 (166)इऌ090C
A7 (167)ईॡ0961
AA (176)ऋॠ0960
B3 (179)कक़0958
B4 (180)खख़0959
B5 (181)गग़095A
BA (186)जज़095B
BF (191)डड़095C
C0 (192)ढढ़095D
C9 (201)फफ़095E
DB (219)िॢ0962
DC (220)ीॣ0963
DF (223)ृॄ0944
EA (234)।ऽ093D

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 language

References
  1. Apple (2005-04-05) [1998-02-05]. "Map (external version) from Mac OS Devanagari encoding to Unicode 2.1 and later". Unicode Consortium.
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