Extended UNIX Code (EUC)
This is a fixed ISO 2022 configuration with G1
(and possibly G2 and/or G3) pre-defined for a particular locale.
No designator sequences or locking shifts are used,
and the 8-bit single shifts are used to access G2 and G3.
Moreover, the glyphs of the 2-byte sets in G1 and G3 are
assumed to be twice as wide as those of the 1-byte set in G2
(and the US-ASCII characters in G0).
Thus the sets and their byte representations are as follows:
- set 0: 00-7F
- US-ASCII (narrow)
- set 1: GR GR
- 2-byte characters (wide)
- set 2: 8E GR
- extra 1-byte set (narrow)
- set 3: 8F GR GR
- extra 2-byte set (wide)
Some examples:
- SHIFT-GB
- G1 = GB 2312-80
- Chinese EUC
- G1 = GB 2312-80,
G2 = row 8 of GB 2312-80 (half width)
- Japanese EUC
- G1 = JIS X0208-1990,
G2 = right half of JIS X0201-1976,
G3 = JIS X0212-1990
- Korean EUC
- G1 = KSC 5601-1987
Somewhat different is
- Taiwanese EUC
- G1 = CNS 11643-1986 level 1,
G2 = 3-byte form of CNS 11643-1986
Part of Notes on CJK Character Codes and Encodings.