If PMDF probes and finds that the message is to be reformatted, it will proceed to check each part of the message. Any text parts are found and their character set parameters are used to generate the second probe. Only when PMDF has checked and found that conversions may be needed does it ever perform the second probe. The input string in this second case looks like this:
out-channelare the same as before, and the
in-char-setis the name of the character set associated with the particular part in question. If no match occurs for this second probe, no character set conversion is performed (although message reformatting, e.g., changes to MIME structure, may be performed in accordance with the keyword matched on the first probe). If a match does occur it should produce a string of the form:
out-char-setspecifies the name of the character set to which the
in-char-setshould be converted. Note that both of these character sets must be defined in the character set definition table,
charsets.txt, located in the PMDF table directory. No conversion will be done if the character sets are not properly defined in this file. This is not usually a problem since this file defines several hundred character sets; most of the character sets in use today are defined in this file. See the description of the
PMDF CHBUILD(OpenVMS) or
pmdf chbuild(UNIX and NT) utility in Chapter 31 and Chapter 32 for further information on the
If all the conditions are met, PMDF will proceed to build the character set mapping and do the conversion. The converted message part will be relabelled with the name of the character set to which it was converted.
6.2.1 Converting DEC-MCS to ISO-8859-1 and Back
Suppose that DEC-MCS is used locally, but this needs to be converted to
ISO-8859-1 for use on the Internet. In particular, suppose the
connection to the Internet is via a set of TCP channels (including but
not limited to
d channels are in use locally. The table shown in
Example 6-1 brings such conversions about.
|Example 6-1 Converting DEC-MCS to and from ISO-8859-1|
CHARSET-CONVERSION IN-CHAN=l;OUT-CHAN=tcp_*;CONVERT Yes IN-CHAN=d;OUT-CHAN=tcp_*;CONVERT Yes IN-CHAN=tcp_*;OUT-CHAN=l;CONVERT Yes IN-CHAN=tcp_*;OUT-CHAN=d;CONVERT Yes IN-CHAN=*;OUT-CHAN=*;CONVERT No IN-CHAN=l;OUT-CHAN=tcp_*;IN-CHARSET=DEC-MCS OUT-CHARSET=ISO-8859-1 IN-CHAN=d;OUT-CHAN=tcp_*;IN-CHARSET=DEC-MCS OUT-CHARSET=ISO-8859-1 IN-CHAN=tcp_*;OUT-CHAN=l;IN-CHARSET=ISO-8859-1 OUT-CHARSET=DEC-MCS IN-CHAN=tcp_*;OUT-CHAN=d;IN-CHARSET=ISO-8859-1 OUT-CHARSET=DEC-MCS
6.2.2 Converting DEC-KANJI to ISO-2022-JP and Back
The table shown in Example 6-2 specifies a conversion between local
usage of DEC Kanji and the ISO 2022 based JP code used on the Internet.
|Example 6-2 Converting DEC-Kanji to and from ISO-2022-JP|
CHARSET-CONVERSION IN-CHAN=l;OUT-CHAN=l;CONVERT No IN-CHAN=l;OUT-CHAN=d;CONVERT No IN-CHAN=d;OUT-CHAN=l;CONVERT No IN-CHAN=d;OUT-CHAN=d;CONVERT No IN-CHAN=l;OUT-CHAN=*;CONVERT Yes IN-CHAN=d;OUT-CHAN=*;CONVERT Yes IN-CHAN=*;OUT-CHAN=l;CONVERT Yes IN-CHAN=*;OUT-CHAN=d;CONVERT Yes IN-CHAN=l;OUT-CHAN=*;IN-CHARSET=DEC-KANJI OUT-CHARSET=ISO-2022-JP IN-CHAN=d;OUT-CHAN=*;IN-CHARSET=DEC-KANJI OUT-CHARSET=ISO-2022-JP IN-CHAN=*;OUT-CHAN=l;IN-CHARSET=ISO-2022-JP OUT-CHARSET=DEC-KANJI IN-CHAN=*;OUT-CHAN=d;IN-CHARSET=ISO-2022-JP OUT-CHARSET=DEC-KANJI