Each computer (host) and terminal operates using a set of letters, numbers and characters from which words and other elementary components of a language are built up, namely the character set.
These character sets can be extended to offer country-specific character representations, such as umlauts (German) or accents (French), at one and the same time within one character set. Unicode is the “fully-developed” form of an extended character set and includes all known text characters in the world in a single character set (see the chapter “Use of UNICODE character sets in PERCON”).
A coded character set (CCS) is the unambiguous representation of the characters of a character set in binary form. The contents of a coded character set and its rules (for example, the sorting sequence and conversion rules) are laid down in international standards.
Example: | The “ä” character is represented in the coded character set |
Each coded character set, or code for short, is defined by its unambiguous name (coded character set name, CCSN).
Example: | The code EBCDIC.DF.03-IRV (International Reference Version) has the |
A list of the existing codes can be found in the appendix of manual [2] "XHCS".
Extended codes supplement the existing
7-bit codes | EBCDIC.DF.03 for hosts and |
with 8-bit codes | EBCDIC.DF.04-x for hosts and |
It is possible to use several codes in parallel.
Requirements
The software product XHCS (eXtended Host Code Support, subsystem XHCS-SYS) is required for generating extended codes in the host and for transferring data between the host and terminal. The manual [2] "XHCS" contains a detailed description of the principles and functions of XHCS and a list of the code tables and names of standard codes.
The terminal emulation should emulate an 8-bit capability terminal. The 8-bit capability of terminal emulation is tested using the software component VTSU.