ISO-2022-JP Encoding

This section provides a quick introduction of ISO-2022-JP encoding, which maps a JIS X0208 character to a 2-byte sequence by using both bytes of the character's code value directly.

ISO-2022-JP: An encoding for JIS X0208 character set. It is a 7-bit encoding with 1 or 2 bytes per character:

Number Of   Valid Range
Bytes       Byte 1        Byte 2       

   1        0x21 - 0x7F
   2        0x21 - 0x7E   0x21 - 0x7E

Of course, 1-byte encoding sequences are used for ASCII characters.

2-byte encoding sequences are used for JIS X0208 characters. The mapping schema is simple. The first byte of a encoding sequence is the high byte value of the character code value. The second byte of a encoding sequence is the low byte value of the character code value.

In another word, ISO-2022-JP encoding maps a JIS X0208 character to a 2-byte sequence with both byte values in the range of from 0x21 to 0x7E.

Escape sequences are used to switch between the 1-byte sequenc mode for ASCII characters and the 2-byte sequence mode for JIS X0208 characters:

<Esc>(J - Escape sequence for ASCII characters
<Esc>$B - Escape sequence for JIS X0208 characters

The advantage of ISO-2022-JP encoding is that it uses 7-bit bytes, which are safe to transmit through any communication interfaces.

The disadvantage of ISO-2022-JP encoding is that it uses escape sequences to mix ASCII characters with JIS X0208 characters.

Last update: 2009.

Table of Contents

 About This Book

 Character Sets and Encodings

 ASCII Character Set and Encoding

 GB2312 Character Set and Encoding

 GB18030 Character Set and Encoding

JIS X0208 Character Set and Encodings

 JIS X0208 Character Set for Japanese Characters

 JIS X0208 Character Code Values

 EUC-JP Encoding

ISO-2022-JP Encoding

 Shift-JIS Encoding

 Unicode Character Set

 UTF-8 (Unicode Transformation Format - 8-Bit)

 UTF-16, UTF-16BE and UTF-16LE Encodings

 UTF-32, UTF-32BE and UTF-32LE Encodings

 Java Language and Unicode Characters

 Character Encoding in Java

 Character Set Encoding Maps

 Encoding Conversion Programs for Encoded Text Files

 Using Notepad as a Unicode Text Editor

 Using Microsoft Word as a Unicode Text Editor

 Using Microsoft Excel as a Unicode Text Editor

 Unicode Fonts

 Unicode Code Point Blocks - Code Charts

 Outdated Tutorials

 References

 PDF Printing Version