Part 4. UN/EDIFACT Rules - Chaper 1. Introduction
All references to the UNTDID (UN/EDIFACT Standard directory) made inthe following text apply equally to the Standard (UNTDID) and theDraft directory with the following exceptions:
a) All references to "UNSM" (United Nations Standard Message) should be replaced with "Draft message"
b) All file and directory names should be changed from EDXX or UNEDXX to TRXX or UNTRXX for the Draft directory (where XX changes depending upon the file/directory in question)
c) All information found in Part 5 of the Draft directories is presented in a draft and NOT a standard version
Chapter 1 - Introduction
This part of UNTDID has been prepared by the UN/EDIFACT Rapporteurs teams with representation from interested WP.4 members and is approved by UN/ECE/TRADE/WP.4 in accordance with the procedure outlined in chapter 2.1.
It contains in chapter 2 the rules and general information on the establishment and use of EDIFACT message types. Together with Part 5 which contains the directories, it constitutes a UNSM manual.
The EDIFACT Rapporteurs are responsible for proposing to WP.4 for agreement, additions, changes and deletions to maintain this part of UNTDID. The EDIFACT syntax in chapter 2.2 is ISO standard 9735. Parts of the UN Trade data elements directory (UNTDED), of which the EDIFACT data elements in Part 5 are an excerpt, is ISO 7372. For ISO 9735 the ISO maintenance rules apply for ISO 7372 an agreement on a Maintenance Agency is in force.
The message types in Part 5, chapter 2, and their supporting material in the chapters thereafter, are based on business requirements; representatives from interested industries and organizations have participated in their preparation.
EDIFACT favors the principle of general usefulness. A UNSM should be generally usable in all applications within its defined function. The same applies for segments in relation to messages and for composite- and simple data elements in relation to segments. To ascertain such alignment, each message type and its components, new or amended, are checked by Maintenance Advisory Groups (MAG) and Technical Assessment Groups (TAG), often combined, within the respective Rapporteurs' Teams and before submitting to WP.4 by its Directories Reference Group (DRG).
In order to be generally useful in all application areas within its defined function, it is evident that a UNSM will allow for more data than will normally be used in any single message. This might discourage some prospective users fearing a large overhead; however, since sub-sets of message types can be defined, messages can be reduced in size to meet user requirements. Similarly, since the syntax rules allow for omission and truncation of unused units remaining in the UNSM, the number of characters transmitted can be reduced significantly.
* Part 5 of this manual includes the UN Standard Message types (UNSM) agreed by WP.4 and their supporting material. New issues of UNTDID will be published two months after WP.4 agreement. Additions, changes and deletions in reference to the previous issue will be marked.