Re: Revision of RFC 1494 - Teletex mapping?

Ned Freed <> Wed, 11 January 1995 02:32 UTC

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From: Ned Freed <>
Subject: Re: Revision of RFC 1494 - Teletex mapping?
In-reply-to: Your message dated "Tue, 10 Jan 1995 08:42:36 +0100" <>
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> a problem with using the ISO 6937 body part, which I think you are talking
> about, is that the spec is simply not available.

There's an easy way to address this -- simply provide the ASN.1 definition
of the damn thing in the MIME-MHS specifications!

We really need to do this, I think, if only because the 6937 stuff does
exist in practice and as such gateways have to be able to deal with it.

FYI, I have similar problems with the FTBP specification. The ASN.1 is for it
is available, in that you can get copies of the X.400-1992 specifications.
However, it is incomplete, in that it depends almost entirely on FTAM, X.500,
and several other sources to complete the definition. (It also isn't completely
consistent with the X.400-1988 FTAM specifications, which leads to real trouble
figuring out what is going on.) I had no choice but to reiterate the full ASN.1
because without it I could not talk sensibly about how to map things.

> Mapping to the ISO 6937 character set rather than the T.61 character set
> might be a good idea, IF we can avoid a mandatory requirement for scanning
> the whole body of a text/plain; charset=ISO6937 body part in order to find
> out whether it can be turned into Teletex or not.

Yeah, this is a real problem, I agree.

> Another problem is that the Teletex body part *allows* character set
> switching; perhaps I (shudder!) need to register a new character set
> like iso-2022-* to match its properties!

It depends. If memory serves, somewhere in the OIW or someplace else there's
some wording that prohibits this. (The actual reference that allows it
in T.61 is fairly obscure in its own right, I believe.)

> Strange thing about GeneralText: It is in fact mandated by the EWOS
> profiles. Its non-support may be indicative of the death of profiling....

Indicative but not causative, I think.