X.400 registered body parts
There is no complete list of body parts available for X.400.
The parts listed here are of 3 kinds:
- Body parts listed in the standards
- Body parts listed by the EMA report and registry
- Body parts that are known from other sources.
For each body part, the source of the specification is noted.
Basic body parts
All these are defined in the [X.420] standard.
- [0] IA5Text
- The most commonly used body part. According to the spec, this
can only carry the ASCII alphabet; in practice, it is often
used to carry 8-bit text; there is no way of finding out which
character set is actually used.
- [3] G3Facsimile
- Used for interworking with fax units, and for moving images
around. See [T.4] and [T.30].
- [4] G4Class1
- A more advanced Fax format. I don't know how much it is
actually used.
- [5] Teletex
- The de facto standard for shipping messages with extended
character sets around in systems using X.400/84.
- [6] Videotex
- I do not know if this is ever used.
- [7] NationallyDefined
- Use of this body part is discouraged. In the first place, few
national body parts were ever used; in the second place,
nations are uninteresting units of standardization for E-mail.
- [9] Message
- Used for forwarding messages.
- [11] MixedMode
- Also a Group 4 fax format, but allows mixing of pictures and
text on a page.
- [14] BilaterallyDefined
- There is almost universal agreement (that is, everyone I know
of except for some very early DEC MailBus implementations) that
this body part contains a single Octet String with the content
of an attached file. There's nowhere to put the filename.
- [15] ExternallyDefined
- See next section
Numbers 1 and 10 (telex and simple formattable documents) are removed
from the 1988 standard, but were in the 1984 standard.
Number 2 (Voice) and 8 (Encrypted) are "for further study" in the 1988
standards; I don't believe they will ever be usd.
Extended body parts
These are standard body part no. 15. Some are defined in the standard,
some are defined outside it. Few public sources for definitions
outside the standard exist.
- GeneralText (n.n.n.n)
- Defined in [X.420]. Used to carry "plain text" with a
richer character set. May be used for Unicode/[ISO 10646].
- FTAM (n.n.n.n)
- Defined in [X.420]. See below.
- mime-body-part (n.n.n.n.1)
- Defined in [RFC 1494]. Not believed to be in use, but may be
generated by gateways written to that spec.
- postscript-body-part (n.n.n.n.2)
- Defined in [RFC 1494]. Not believed to be in use.
- JPEGBodyPart (n.n.n.n.3)
- Defined in RFC 1494. Not believed to be in use.
- gif-body-part (n.n.n.n.4)
- Defined in RFC 1494. Not believed to be in use.
FTAM body parts
These are extended body parts, defined by the OID (n.n.n.n.n)
Most of the data below are from the EMA MAWG report.
- ema-unknown-body (n.n.n.n)
- Defined in [MAWG]. Used for transporting any content for which
there is no proper label.
- MS-Word (n.n.n.n.n)
- Defined in [MAWG]. Microsoft contact is Sukhvinder Singh Gill
<mailaddress@microsoft.com>
Harald.T.Alvestrand@uninett.no
Last modified: Wed Jul 3 13:42:08 1996