KEIS

KEIS is a stateful EBCDIC charset used in Hitachi mainframe systems. KEIS is an acronym for "Kanji processing Extended Information System".

Encoding structure

Here are the valid ranges of bytes according to its encoding structure.

Byte Range Purpose	Byte Range in Hexadecimal	Comment
single byte	41-F9	Includes graphic characters. Does not include unassigned characters nor ISO control characters.
full width space	40 40 or A1 A1
shift to single byte mode	0A 41
shift to double byte mode	0A 42
first byte of double byte	40, 41-FE	A1-CF is the basic set. D0-FE is extended set 1. 59-80 is extended set 2. 81-A0 are user defined characters. Byte 40 is only valid when followed by byte 40.
second byte of double byte	40, 41-FE	40 is only valid when preceded by byte 40. 0x40 0x40 makes the ideographic space character. Normally only A1-FE is used.

References

• Lunde, Ken. CJKV Information Processing. Sebastopol, Calif.: O'Reilly & Associates, 1998. ISBN 1-56592-224-7. (Note that Appendix D has a typo for the hexadecimal ranges for KEIS. The decimal ranges were used for the encoding structure.)