Re: Revision of RFC 1494 - Teletex mapping?

"Carl S. Gutekunst" <csg@hideji.worldtalk.com> Mon, 09 January 1995 23:33 UTC

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Date: Mon, 9 Jan 1995 15:14:05 -0800
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From: "Carl S. Gutekunst" <csg@hideji.worldtalk.com>
Message-Id: <199501092314.PAA25456@hideji.worldtalk.com>
To: Harald.T.Alvestrand@uninett.no
Cc: mime-mhs@surfnet.nl
Subject: Re: Revision of RFC 1494 - Teletex mapping?
In-Reply-To: Your message of Fri, 06 Jan 1995 11:10:34 +0100 <199501061010.LAA00394@dale.uninett.no>

>Teletex -> Text/plain; charset="T.61" (with pagebreaks being
>converted to formfeeds).
>Text/plain; charset="T.61" -> GeneralText
>Downgrade from GeneralText to Teletex when going from '88 to '84
>
>Do you all think this would be an useful extension of the standard?

Like it or not, yes; but, I'd go with ISO 6937 as the basis rather than T.61,
as it is a superset.  (You can support T.61 bodies in 6937, but not the other
way around.)  6937 also seems to be more widespread, at least in the Western
Hemisphere.  Downgrading to a 1984 Teletex part is possible, usually without
degradation.

I am not crazy about putting Teletex in MIME bodies or header strings; I would
rather gateways mapped to a "native" MIME site, i.e., ISO 8859.1.  And vendors
should be strongly encouraged to do this when they can.  But, alas, there are
widely used characters in T.61 and ISO 6937 that don't map to 8859.1, or
(worse) require character set switching among several 8859.x sets, something
we don't yet support in MIME bodies.  You can solve that problem with Unicode,
but UCS-2 does not have a lot of penetration yet.  (I am also very unhappy
with the current drafts for UCS-2 in MIME, but that's a different issue....)

Also, the mapping of preference should be to '84 Teletex, if it fits, or to
the ISO 6937, if it's available; GeneralText should be used only as a last
resort, since support for it in the marketplace is extremely poor.

<csg>