Re: TV teletext [and Unicode]

From: Alain LaBont\i\ (
Date: Tue Oct 13 1998 - 14:08:29 EDT

At 08:50 98-10-13 -0700, Markus Kuhn wrote:
>"M.T. Carrasco Benitez" wrote on 1998-10-13 13:39 UTC:
>> Looking for information on the character sets
>> used by "TV teletext" and in particular a
>> mapping to Unicode.

[Markus] :
>I thought, TV teletext character sets were considered to be outside the scope
>of Unicode, as their numerous colorful block graphic characters are a very
>specialized application, and especially the block graphics characters make
>only sense together with color control commands since much of the displayed
>information is encoded in the color. However I am sure someone will put
>them one day in plane 1 or so.
>Which country? There are a number of different teletext and videotext
>standards around. One standard is ITU-T Recommendation T.101/T.107
> <http://www/itu/ch/>, another is NAPLPS (CSA T 500-1983).

[Alain] :
By the way, when we made the latest edition of Canadian standard CAN/CSA
Z243.4.1 (ordering standard), we documented a mapping between CSA T.500
character set (used for NAPLPS, i.e. a protocol used on TV sets essentially
nowadays) and ISO/IEC 10646-1 (Unicode). CSA T.500 character répertoire is
practically identical to ISO/IEC 6937 for text (it alsoincludes a
supplement for alpha-geometric characters like those used for line drawings).

If this can be of help, even if the standard is not about this, we had to
take a decision about this mapping, as we wanted to decouple ordering from
particular coding and we refered to the largest of the character sets for
the repertoire, i.e. the UCS.

So: see CAN/CSA Z243.4.1-1998 (the standard was revised during the last 2
years and republished last March).

You can also see, for an extra mapping reference, standard CAN/CSA
Z243.230-1998 (Canadian minimum software localization parameters), which
documents locales for English and for French according to Canadian habits,
using the above ordering standard in both locales for the LC_COLLATE part.
These locales, also decoupled from coding, are based on the use of 3
repertoires, one of which is NAPLPS.

These two standards are national standards of Canada (i.e. these are CSA
standards *but* also standards adopted by Standards Council of Canada --
both with versions in English and in French, like *all* national standards
of Canada -- national standards of Canada are refrenced using the prefix
"CAN/" in front of the standard's number, each standard document being
issued by one of many standards organizations under Standards Council of
Canada [manager of the "Canadian system of standards"], the main ones being
CSA [Canadian Standards Organization], BNQ [Bureau des normes du Québec],
ONGC [Office des normes générales du Canada; not sure about the English
name, I quote this one from memory]).

In passing we also have a national keyboard standard that is consistent
with these standards for text entry (CAN/CSA Z243.200, under revision [1st
edition 1988, second edition 1992]). We plan to include full support of
Latin 9, including EURO, in the revision (<OE>, <oe> and <Y DIAERESIS> are
already upported, as it is also a user interface standard not dependent on
an actual encoding -- that is the keyboard which I use, the version I use
supports all of Latin 1 plus <OE>, <oe> and <Y DIAERESIS>, it only needs to
support the EURO SIGN to support the Latin 9 répertoire).

Alain LaBonté
CAN/CSA Z243.4.1 (Ordering) Project editor
CAN/CSA Z243.230-1998 (Localization) coeditor
CAN/CSA Z243.200 (Keyboard) project leader

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