DBCS code scheme

IBM® supports two DBCS code schemes: one for the host systems, the other for personal computers.

The IBM-host code scheme has the following code-range characteristics:

First byte: Hexadecimal 41 to hexadecimal FE
Second byte: Hexadecimal 41 to hexadecimal FE
Double-byte blank: Hexadecimal 4040

In Figure 1, using the first byte as the vertical axis and the second byte as the horizontal axis, 256 x 256 intersections or code points are expressed. The lower-right code area is designated as the valid double-byte code area and x is assigned to the double-byte blank.

Figure 1. IBM-host code scheme

Graphic depicting the IBM host code scheme

By assigning the values hexadecimal 41 to hexadecimal FE in the first and second bytes as the DBCS codes, the codes can be grouped in wards with 192 code points in each ward. For example, the code group with the first byte starting with hexadecimal 42 is called ward 42. Ward 42 has the same alphanumeric characters as those in a corresponding single-byte EBCDIC code page, but with double-byte codes. For example, the character A is represented in single-byte EBCDIC code as hexadecimal C1 and in IBM-host code as hexadecimal 42C1.

The IBM i operating system supports the following double-byte character sets:

IBM Japanese character set
IBM Korean character set
IBM Simplified Chinese character set
IBM Traditional Chinese character set

The following tables show the code ranges for each character set and the number of characters supported in each character set.

Table 1. IBM Japanese character set
Wards	Content	Number of characters
40	Space in 4040	1

41 to 44	Non-Kanji characters Greek, Russian, Roman numeric (Ward 41) Alphanumeric and related symbols (Ward 42) Katakana, Hiragana, and special symbols (Ward 43-44)	549

45 to 55	Basic Kanji characters	3226

56 to 68	Extended Kanji characters	3487

69 to 7F	User-defined characters	Up to 4370

80 to FE	Reserved

Total number of IBM-defined characters: 7263

Table 2. IBM Korean character set
Wards	Content	Number of characters
40	Space in 4040	1

41 to 46	Non-Hangeul/Hanja characters (Latin alphabet, Greek, Roman, Japanese Kana, numeric, special symbols)	939

47 to 4F	Reserved

50 to 6C	Hanja characters	5265

6D to 83	Reserved

84 to D3	Hangeul characters (Jamo included)	2672

D4 to DD	User-defined characters	Up to 1880

DE to FE	Reserved

Total number of IBM-defined characters: 8877

Table 3. IBM Simplified Chinese character set
Wards	Content	Number of characters
40	Space in 4040	1

41 to 47	Non-Chinese characters (Latin alphabet, Greek, Russian, Japanese Kana, numeric, special symbols)	712

48 to 6F	Chinese characters: Level 1 and Level 2	3755 and 3008

70 to 75	Reserved

76 to 7F	User-defined characters	Up to 1880

80 to FE	Reserved

Total number of IBM-defined characters: 7476

Table 4. IBM Traditional Chinese character set
Wards	Content	Number of characters

40	Space in 4040	1

41 to 49	Non-Chinese characters (Latin alphabet, Greek, Roman, Japanese Kana, numeric, special symbols)	1003

4A to 4B	Reserved

4C to 68	Primary Chinese characters	5402

69 to 91	Secondary Chinese characters	7654

92 to C1	Reserved

C2 to E2	User-defined characters	Up to 6204

E3 to FE	Reserved

Total number of IBM-defined characters: 14060

This code scheme applies to the System i®, System/36, System/38, as well as the System/370 platform. A different DBCS code scheme, called the IBM Personal Computer DBCS code scheme, is used on the Personal System/55. For details of the IBM Personal Computer DBCS code scheme, refer to IBM PS/55 publications.