Exchange/RJE Manual

Modifying Your Translation Table
Character Set Translation
B–10 104698 Tandem Computers Incorporated
Modifying Your
Translation Table
This section explains how to modify the translation tables that Exchange/RJE uses to
translate from ASCII to EBCDIC and back when sending and receiving transparent
data. You may want to modify these tables to support a national character set other
than USASCII or to implement a translation other than the supplied translation.
When Text Is Translated Normal text is translated by Envoy or CP6100, rather than by Exchange/RJE. If you
are transmitting normal text, modifying the translation tables as described in this
section will not change the translation of the text you are transmitting.
Transparent text is translated by Exchange/RJE only when you elect the translation by
specifying the TRANSLATE parameter on the appropriate SEND or RECEIVE
command. Normally, you do not transmit textual data as transparent text, and it may
be inappropriate to translate other types of data, such as binary numbers. However, if
you need to modify the translation tables for Exchange/RJE, you can follow the
guidelines in this section.
How to Modify the
Translation Tables
The Exchange/RJE line server (RJESV) uses two tables for translating from ASCII to
EBCDIC and back. The array ASCII^TO^EBCDIC contains the ASCII code for each
EBCDIC character. The array EBCDIC^TO^ASCII contains the EBCDIC code for each
ASCII character. For both of the tables, the nth byte of the table contains the translated
code for the nth character. For example, in ASCII^TO^EBCDIC, the forty-eighth
character (%H30), which is the ASCII code for 0 (zero), contains %HF0 which is the
EBCDIC code for 0. In EBCDIC^TO^ASCII, the two-hundred-fortieth character
(%HF0) contains the ASCII code for 0, %H30. Note that the index for each table begins
with 0 (rather than 1).
You can use the BINDER program to examine and modify both ASCII^TO^EBCDIC
and EBCDIC^TO^ASCII. To examine the tables, use the BINDER DUMP command.
To modify the tables, use the BINDER MODIFY command. After you modify the
tables, use the BINDER BUILD command to build a new version of the line server that
contains the modified tables.
When you use the BINDER program, you reference each table by its name (which
specifies the base of the table) and then specify an offset into the table. The offset is
interpreted as an octal value and is a word offset. You must modify the table one
word (two bytes) at a time. To modify only one byte, specify the new value for that
byte and the old value for the other byte in that word.
If after you build a new line server with the modified translation tables, you need to
run Exchange/RJE with the original translation tables, simply start the line server
from an unmodified version of the object file.