ISO 9735-3:2002

Overview

ISO 9735-3:2002 - part of the EDIFACT application-level syntax rules - specifies syntax rules specific to interactive EDI (I‑EDI). It defines how interactive (conversational) EDIFACT messages are structured and exchanged between application systems in administration, commerce and transport. The standard uses Syntax version number: 4 and Syntax release number: 01 and is intended for message-level interoperability; communication protocols themselves are explicitly out of scope.

Key topics

• Scope and conformance
  • Rules for I‑EDI interchange and message structures and conformance requirements that reference ISO 9735-1 and ISO 9735-10.
  • Use of syntax version and release identifiers (for backward compatibility across ISO 9735 releases).
• I‑EDI interchange structure
  • Ordered sequence of service string advice, interactive interchange header and trailer, and optional message content.
  • Reference to interactive header/trailer segments (defined in ISO 9735-10).
• I‑EDI message and transaction model
  • Definition of message composition within a transaction: interactive message header (UIH), message body (segments and segment groups), and interactive message trailer (UIT).
  • Segment, composite and component data element nesting and repetition rules.
• Dialogue control and transactional flow
  • Rules describing dialogues as paired initiator/responder interchanges, message pairing, allowable message sequences, and options for combining messages with headers/trailers.
  • Provisions for interleaving service segments (e.g. UIR) and for premature dialogue termination.
• Informative annexes
  • Examples illustrating segment sequences, function/state models and a conceptual I‑EDI process model to aid implementation.

Applications

ISO 9735-3:2002 is used by:

• EDI implementers and system integrators building interactive (real‑time or conversational) message exchanges using EDIFACT.
• Software vendors developing middleware, gateways or EDI translators that must support I‑EDI syntax rules (UIB/UIZ/UIH/UIT semantics).
• Business sectors such as transport, logistics, retail and public administration that require short-response interactive exchanges tied to a single business transaction.
• Standards and compliance teams validating conformance to EDIFACT interactive syntax as part of interoperability testing.

Practical benefits include consistent message structure for interactive transactions, predictable dialogue control, and alignment with the UN Trade Data Interchange Directory (UNTDID) message design guidelines.

Related standards

• ISO 9735-1: Syntax rules common to all parts (mandatory for conformance)
• ISO 9735-2: Batch EDI rules (for batch vs interactive comparisons)
• ISO 9735-10: Syntax service directories and interactive header/trailer definitions
• UN/EDIFACT and UNTDID message design guidance maintained by UN/CEFACT

Keywords: ISO 9735-3, EDIFACT, interactive EDI, I‑EDI, application level syntax, UIH, UIT, UIB, UIZ, UNTDID, syntax version 4.