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Part 1: Introduction

1. Trade facilitation deals with the requirements and procedures related to the flow of information needed for the international movement of goods. Traditionally, these requirements have been substantiated in the form of paper documents and procedures carried out through handling such documents; it was therefore only natural that initial facilitation efforts should focus on the simplification and standardization of external trade documents.
 2. Technological developments, however, have made alternative information handling and transmission methods feasible; in addition, the scope of international co-operation has been extended from document harmonization to more profound research on the identification of basic information requirements and the development of an entirely new methodology to satisfy them. It is significant that the UN/ECE Working Party on the Simplification and Standardization of External Trade Documents, set up in 1960, became in 1972 the Working Party on Facilitation of International Trade Procedures, with terms of reference extended to cover, inter alia, the development of a standard international trade data terminology and a uniform system for use in automatic processing and transmission of trade data.
 3. As a result of efforts to bring order into the field of paper documentation, the almost universal acceptance of the United Nations (previously ECE) Layout Key for Trade Documents, besides offering substantial cost reductions in paper handling, created a sound basis for further international standardization in trade data interchange. Through the United Nations layout key, discipline was introduced in the size and format of international trade documentation, establishing maximum dimensions of data elements to be shown on documents, defined in terms of number of characters per line and number of lines per box. The field headings to be shown on aligned documents were grouped by broad function (e.g. parties, transport information, references, goods details, etc.), thus facilitating their analysis with a view to rationalization and standardization of information accompanying international trade. 
4. The handling of trade data includes two major types of activity, processing and transmission. As to the processing of information, the development of automatic data processing equipment which can be used for commercial applications has introduced a powerful rationalization tool for those involved in international trade. Although data processed automatically can, without difficulty, be presented in normal paper documents, subsequently to be forwarded and handled in the traditional way, the obvious and very desirable alternative is to make the information directly available to exchange partners having data processing equipment at their disposal.
 5. This introduces--quite apart from the method used for processing data prior to transmission--a need to rationalize the physical transmittal of data, from the slow and cumbersome mailing of documents to more direct and rapid information exchange. It is evident that, when using automatic data interchange, a much more rigid discipline needs to be exercised regarding data presentation and exchange rules than in the case of paper documents.
 6. Even though the required technology and services are available, this does not suffice to make data interchange of this type an operational reality. There is an equally important requirement to develop and agree on standards, procedures, and other essential elements of data handling methodologies to ensure intelligible communications between different systems used by trade and trans- port operators.
 7. The first steps in rationalization aiming at the use of automatic data processing and transmission were the development of agreed standards for the representation of data used to service international trade movements and of methods whereby the exchange of data between data processing systems would be made possible without the need for costly and error-prone re-transcription.
 8. When data are interchanged between trade partners by means other than paper documents, e.g. by teletransmission methods including direct exchange between computer systems, a common "language" should be used with an agreed mode of expressing it, i.e. common protocols, message identification, agreed abbreviations or codes for data representation, message and data element separators, etc. If a universally-accepted standard is not used, the "language" has to be agreed bilaterally between each pair of interchange partners. Taking into account the large number of parties exchanging data for an international trade transaction and the ever increasing number of potential users of teletransmission techniques, it is obvious that such a bilateral approach is not viable.
 9. Besides using compatible systems, interchange partners should follow uniform rules in respect of communication procedures which include the types of messages acceptable, identification of parties, reference to previously-agreed protocols or agreements on character set, language, transliteration and interchange structure (specification of the various parts of the message, identification of the data elements, codes used).
 10. International co-ordination in the development of uniform communication protocols for various types of communication networks (both private and public) is ensured through such specialized international bodies as the International Telecommunication Union (ITU), International Telegraph and Telephone Consultative Committee (CCITT), ISO TC 97/SC 6 "Data Communication", etc. Reference should also be made to the Basic Reference Model for Open Systems Interconnection (OSI), ISO 7498.
 11. As for the Working Party on Facilitation of International Trade Procedures, its programme of work includes the preparation of recommendations on data elements and their structure and on standard message formats. In the framework of the Working Party, Meetings of Experts deal with the rationalization of data (GE.l) and the establishment of optimal conditions for the application of automated data transmission methods (GE.2).
 12. Much credit for the pioneering work in the field of interchange of international trade data must be given to the United Kingdom. As early as 1974, in a report to the Working Party on Facilitation of International Trade Procedures (document TRADE/WP.4/GE.l/R.38), the delegation of the United Kingdom described "proposals for providing standard ways of representing information in messages passing between partners in international trade". In April 1975, an ad hoc meeting was held in Stockholm with the aim of setting out basic principles and of defining requirements for trade data interchange. The conclusions agreed upon at that time (document TRADE/WP.4/GE.l/R.54, 1 May 1975) may be summarized as follows:
  •  12.1 The rules to be established for the structuring of data should be independent of system, machine and media constraints and should allow for human interpretation of the data transferred.
  •  12.2 The character set used for transmission should be limited to that sub-set of International Alphabet 2 which is universally available and the equivalent characters in International Alphabet 5 (ISO 646); for the time being the characters "+", "=", ":", "'" should be used as separating characters. It was later found that the character "=" would not be required as a separator.
  •  12.3 The definition, size and format of data elements should be established on the basis of existing aligned documents.
  •  12.4 The data elements or groupings which are part of standard messages should be independent of each other so that one part may be changed without affecting any other part.
  •  12.5 Provision should be made for the requirements of organizations with specialized needs such as the mass transfer of data.

 13. Aware of interest in the matter and the urgency for a solution, the Working Party set up two ad hoc task teams under the Group of Experts on Automatic Data Processing and Coding, one with the task of "establishing the standard data elements required in international trade and to identify those which need coded representation" (document TRADE/WP.4/GE.l/R.60), the other to establish "a set of standards for data exchange between inter- national trade partners over data communication links, and for computer exchange using various media (for example the physical exchange of magnetic tapes)" (document TRADE/WP.4/GE.l/R.6l).
 14. After three years of work, and taking into account parallel studies conducted in individual countries and other organizations, in 1978 the task teams reached the stage where a major part of the data elements study had been accomplished and where a number of principles for data transmission, including a set of interchange rules, had been decided on. It had been very forcefully argued that the goal would be to agree on one system only, even if that implied the need to accept a solution which would not be the ideal one for each particular field of application.
 15. During a certain period of time, however, owing to the limited amount of experience gained in electronic data interchange on an international basis and the different requirements and capabilities of the various national entities taking an interest in the subject, the co-existence of a number of trade data interchange protocols, corresponding to particular user's needs, had to be accepted whilst efforts towards a unique standard continued within the Working Party.
 16. A first set of interchange rules was developed and published in 1981 in the form of "Guidelines for Trade Data Interchange" (GTDI) which offered potential users a basis for developing their systems. Later on, in the light of experience gained by the many users of GTDI and the various projects under way, the Guidelines were enhanced with a view to permitting their wider acceptance.
 17. The next stage in the work towards a common universal set of interchange rules for trade data was a reconciliation, carried out by a joint European/North American ad hoc Group, known as UN-JEDI, commissioned by the Working Party on Facilitation of International Trade Procedures, to bring together the enhanced GTDI and a set of standards for Electronic Business Data Interchange developed in the United States. The recommendations of the UN-JEDI Group were agreed by the Working Party at its September 1986 session. They led to the development of the United Nations Electronic Data Interchange for Administration, Commerce and Transport (UN/EDIFACT) syntax rules, which are incorporated in Part 4 of the present Trade Data Interchange Directory (UNTDID).

Principles for trade data interchange

18. The principles for the establishment of any trade data interchange method or system may be summarized as follows:
  •  18.1 The basis for any trade data interchange is the United Nations Trade Data Elements Directory (UNTDED), where data elements are uniquely named, tagged and defined, and where the representation of data entries is specified both as regards expression and syntax. From this directory, data elements required to fulfill specific documentary functions are selected both for UNLK based forms and to form messages for transmission. Data elements from UNTDED used in UN Standard Message types are also part of a separate directory (EDED) in UNTDID.
  •  18.2 Data elements can be grouped in various sets, systematically arranged according to agreed rules. These groups (or "segments"), which are designated by a common denominator (a segment tag), can be arranged as specified in United Nations Standard Message types (UNSM's) or by agreement between interchange partners. Each data elements is implicitly identified by its position in the segment.

 19. Data elements in the United Nations Trade Data Elements Directory (UNTDED) are used in the segments specified in the present United Nations Trade Data Interchange Directory (UNTDID) and are also, in a condensed form for this purpose, included in a special directory (UNEDED).

Presentation of the UN Trade Data Interchange Directory (UNTDID)

 20. Part 2 of UNTDID contains the "Uniform Rules of Conduct for Interchange of Trade Data by Teletransmission" (UNCID), jointly developed by the Working Party on Facilitation of International Trade Procedures, UNCITRAL, the Nordic Legal Committee, the Customs Co-operation Council and other international organizations, in the framework of a Special Joint Committee of the International Chamber of Commerce.
 21. Part 3 will define the terminology used and contains a list of technical standards and recommendations which form the basis for the technical solutions accounted for in the Directory.
 22. Part 4 includes the general UN/EDIFACT rules and guidelines for syntax, syntax implementation and message design and a general introduction to UNSM descriptions. 
 23. Part 5 includes the approved UNSM specifications in the message type directory (UNEDMD) and in supporting directories, segments (UNEDSD), composite data elements (UNEDCD), data elements (UNEDED) and code lists (UNCL).
 24. An additional part is foreseen to include Guidelines for users of the UN/EDIFACT Data base.

Definition of UN/EDIFACT

 25. At its meeting 1990-03, Working Party 4 agreed on the following definition of UN/EDIFACT:
 26. United Nations rules for Electronic Data Interchange For Administration, Commerce and Transport. They comprise a set of internationally agreed standards, directories and guidelines for the electronic interchange of structured data, and in particular that related to trade in goods and services between independent, computerized information systems.
 27. Recommended within the framework of the United Nations, the rules are approved and published by UN/ECE in the (this) United Nations Trade Data Interchange Directory (UNTDID) and are maintained under agreed procedures.