EM> Hапомните пожалуйста по кладжам CHRS и CHARSET. Чем например CHRS: EM> IBMPC отличается от CHRS: IBMPC 2 с двойкой на конце?
2. Character set identification line ------------------------------------
The character encoding of a message is specified in the "CHRS" control line.
The CHRS control line is formatted as follows:
^ACHRS: <identifier> <level>
Where <identifier> is a character string of no more than eight (8) ASCII characters identifying the character set or character encoding scheme used, and level is a positive integer value describing what level of CHRS the message is written in.
For backwards compatibility, "CHARSET" may be treated as a synonym for "CHRS".
Some implementations do not add the <level> field and some implementations erroneously present "UTF-8 2" instead of "UTF-8 4". Well mannered implementations should gracefully handle this situation when reading messages. The recommended way of doing this is to ignore the level parameter and only use the name of the identifier. In future the level parameter may become obsolete.
Incoming messages without "CHRS" control lines should be considered as being written in pure ASCII, but may be treated as being written in some default character set or character encoding scheme. Such as IBM codepage 437, IBM codepage 866 or UTF-8. It is recommended that message readers offer the user the option of manually selecting a different character set or encoding scheme for these messages on a per-area, per-message or other basis.
3. Supported levels -------------------
These levels are the ones that are implemented in current software:
Level 0 -------
This level is for messages containing pure seven bit ASCII only. Outgoing messages in pure ASCII need not be identified by a "CHRS" control line, but if they are, they should be indicated as "ASCII 1" (not "ASCII 0").
Level 1 -------
First level of internationalisation, using seven bit character sets. Most of these are based on US ASCII, with minor internationalisation variations.
Level 2 -------
Second level of internationalisation, using eight bit character sets.
This level adds support for character sets that use "extended ASCII", i.e codes with the most significant bit set. The character sets in level two are all based on ASCII (the codes 0-127 coincide with ASCII).
Level 3 -------
Level 3 is included just for completeness as it was mentioned in the proposals (FSC-0054 and FSP-1013, now FRL-1020) that this standard is based on.
It seems level 3 was originally meant for 16 bit character sets but there never was an implementation and there may never be. This may have to do with the NULL byte being reserved in the Fidonet specifications as a termination character.
Level 3 is "reserved".
Level 4 -------
Level 4 is for multi byte character encodings. The only presently known implementation is UTF-8.
Eugene
--- GoldED+/LNX 1.1.5-b20160827 * Origin: FireFox Station (2:5075/35)
