JEF is a stateful EBCDIC

EBCDIC

Extended Binary Coded Decimal Interchange Code is an 8-bit character encoding used mainly on IBM mainframe and IBM midrange computer operating systems....

 charset used in Fujitsu

Fujitsu

is a Japanese multinational information technology equipment and services company headquartered in Tokyo, Japan. It is the world's third-largest IT services provider measured by revenues....

 mainframe

Mainframe computer

Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

 systems called FACOM and some OASYS series personal word processors. JEF is an acronym for "Japanese processing Extended Feature". It was introduced by Fujitsu in April 1979, but the implementation actually predates JIS C 6226-1978

JIS X 0208

JIS X 0208 is a 2-byte character set specified as a Japanese Industrial Standard, containing 6879 graphic characters suitable for writing text, place names, personal names, and so forth in the Japanese language. The official title of the current standard is...

.

Encoding structure

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

Byte Range Purpose	Byte Range in Hexadecimal Hexadecimal In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...	Comment
single byte	41-F9	Includes graphic characters. Does not include unassigned characters nor ISO control characters.
shift to single byte mode	29
shift to double byte mode	28
first byte of double byte	40, 41-7D, 7F-FE	A1-FE are JIS C 6226-1978 JIS X 0208 JIS X 0208 is a 2-byte character set specified as a Japanese Industrial Standard, containing 6879 graphic characters suitable for writing text, place names, personal names, and so forth in the Japanese language. The official title of the current standard is... characters. 41-7D, 7F are extended characters. 80-A0 are user defined characters. Byte 40 is only valid when followed by byte 40.
second byte of double byte	40, A1-FE	40 is only valid when preceded by byte 40. 0x40 0x40 makes the ideographic space character.

External links

• The Japanese Language Information System JEF