Extended UNIX Code (EUC) Code Set

The EUC code set uses control characters to identify characters in some of the character sets. The encoding rules are based on the ISO2022 definition for the encoding of 7-bit and 8-bit data. The EUC code set uses control characters to separate some of the character sets.

The term EUC denotes these general encoding rules. A code set based on EUC conforms to the EUC encoding rules but also identifies the specific character sets associated with the specific instances. For example, eucJP for Japanese refers to the encoding of the JIS characters according to the EUC encoding rules.

The first set (CS0) always contains an ISO646 character set. All of the other sets must have the most-significant bit (MSB) set to 1, and they can use any number of bytes to encode the characters. In addition, all characters within a set must have:

• Same number of bytes to encode all characters

• Same column display width (number of columns on a fixed-width terminal)

Each character in the third set (CS2) is always preceded with the control character SS2 (single-shift 2, 0x8e). Code sets that conform to EUC do not use the SS2 control character other than to identify the third set.

Each character in the fourth set (CS3) is always preceded with the control character SS3 (single-shift 3, 0x8f). Code sets that conform to EUC do not use the SS3 control character other than to identify the fourth set.