ISO/IEC 10021-9:1995/Amd 1:1998

INTERNATIONAL ISO/IEC
STANDARD 10021-9
First edition
1995-08-01
AMENDMENT 1
1998-07-01
Information technology — Message
Handling Systems (MHS) —
Part 9:
Electronic Data Interchange Messaging
System
AMENDMENT 1: Compression extension
Technologies de l’information — Systèmes de messagerie (MHS) —
Partie 9: Système de messagerie avec échange de données informatisé
AMENDEMENT 1: Extension de compression
B C Reference number
ISO/IEC 10021-9:1995/Amd.1:1998(E)

ISO/IEC 10021-9:1995/Amd.1:1998(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the
International Electrotechnical Commission) form the specialized system
for worldwide standardization. National bodies that are members of ISO
or IEC participate in the development of International Standards through
technical committees established by the respective organization to deal
with particular fields of technical activity. ISO and IEC technical
committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO
and IEC, also take part in the work.
In the field of information technology, ISO and IEC have established a
joint technical committee, ISO/IEC JTC 1. Draft International Standards
adopted by the joint technical committee are circulated to national bodies
for voting. Publication as an International Standard requires approval by at
least 75 % of the national bodies casting a vote.
Amendment 1 to ISO/IEC 10021-9:1995 was prepared by Joint Technical
Committee ISO/IEC JTC 1, Information technology.
This Amendment is also published by ITU-T, but not as identical text.
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ISO/IEC ISO/IEC 10021-9:1995/Amd.1:1998(E)
Information technology — Message Handling Systems (MHS) —
Part 9: Electronic Data Interchange Messaging System
AMENDMENT 1: Compression extension
1. Insert at the end of clause 2
" CCITT Recommendation V.42 bis (1990), Data Compression Procedures for data circuit terminating equipment (DCE) using
error correction procedures"
2. Insert new subclauses at the end of 8.2.19 as follows :
8.2.19.1 Compression Extension introduction
The following extension describes the parameters that need to be exchanged when the primary body part is transferred in a
compressed mode. The absence of this parameter implies that the content of the primary body part is not compressed.
primary-body-part-compression-indication EDIM-EXTENSION
CompressionParameter--as defined for P2 File Transfer Body Part
CRITICAL FOR DELIVERY
::= id-edi-compression
The syntax of this parameter is that of the corresponding parameter in the file transfer body-part defined in ITU-T Rec.
X.420/ISO/IEC 10021-7.
The following macro gives a notation to express an instance of the compression extension.
COMPRESSION-ALGORITHM MACRO ::=
BEGIN
TYPE NOTATION ::= type | empty
VALUE NOTATION ::= value ( VALUE OBJECT IDENTIFIER )
END
NOTE: Although this specification identifies V.42 bis compression, other compression algorithms may be used.
8.2.19.2 V.42bis compression
The following instance of the COMPRESSION-ALGORITHM macro defines the parameters needed to perform V.42 bis
compression as stated in the CCITT Recommendation V.42 bis(1990).
V42BisCompression COMPRESSION-ALGORITHM V42BisCompressionParameter
::= id-e
...