EDI and GS1: Electronic Data Interchange Standards

1. What Is EDI and GS1?

1.1 What Is EDI?

Electronic Data Interchange (EDI) is the computer-to-computer exchange of business documents in a standardised electronic format between trading partners. EDI replaces paper-based processes like purchase orders, invoices, and despatch advices with structured electronic messages, reducing manual data entry, errors, and processing time.

EDI is not email attachments or PDFs — it is a structured, machine-readable format where each piece of information (item code, quantity, price, date) occupies a defined position in the message, allowing the receiver's system to process it automatically.

1.2 What Is GS1?

GS1 is a neutral, not-for-profit organisation that develops and maintains global standards for business communication. GS1 standards operate on three layers:

GS1 EDI sits in the Share layer. It integrates electronic information sent between trading partners with the physical flow of goods by using GS1 identification keys (GTIN, GLN, SSCC) as the common language across all messages.

1.3 Common Use Cases

2. GS1 EDI Standards Overview

2.1 EANCOM (UN/EDIFACT Subset)

GS1 EANCOM is a GS1 subset of the UN/EDIFACT standard (United Nations Electronic Data Interchange for Administration, Commerce and Transport). It contains only the message elements required by business applications and mandated by the syntax — omitting optional elements not relevant to GS1 users.

Key characteristics:

• Based on UN/EDIFACT D.16B syntax
• Two active syntax editions: Syntax 3 (2022) and Syntax 4
• Integrates GS1 identification keys (GTIN, GLN, SSCC) so that codes are recognised globally
• Used across retail, healthcare, transport, and technical industries
• Ready-to-use — eliminates the work of adapting the full UN/EDIFACT standard

Data format: EANCOM messages use the UN/EDIFACT syntax — variable-length records with segment tags and element separators (typically + for element separation and ' for segment termination). The messages are transmitted as plain text files, often compressed and sent via AS2, AS4, or SFTP.

2.2 GS1 XML

GS1 XML is an alternative XML-based EDI standard that provides the same business semantics as EANCOM but uses XML syntax. It is designed for organisations that prefer XML-based integration, offering:

• Well-formed XML documents with XSD schemas
• Same GS1 business message definitions as EANCOM
• SOAP and REST-based transport options
• Support for Syntax 3 and Syntax 4 message versions

2.3 GS1 eCom

GS1 eCom is the umbrella term covering both EANCOM and GS1 XML. Both standards carry the same business content — the choice is purely a syntax preference. GS1 provides implementation guidelines for both forms.

2.4 Comparison

3. EANCOM Message Structure

3.1 Hierarchy

An EANCOM transmission follows a four-level hierarchy:

Interchange (UNB ... UNZ)
  ├── Message (UNH ... UNT)
  │     ├── Segment Group (SG)
  │     │     ├── Segment (e.g. NAD, LIN, QTY)
  │     │     │     ├── Data Element (e.g. 7140, C186)
  │     │     │     │     ├── Element Value (e.g. "54012345678901")
  │     │     │     │     └── (more elements)
  │     │     └── Nested Segment Groups
  │     └── (more messages)
  └── (more interchanges)

3.2 Interchange Level

3.3 Message Level

3.4 Segment Groups

Segments are grouped into logical clusters called Segment Groups (SG). For example, the ORDERS message uses SG1 for party identification (NAD segments), SG7 for line item detail (LIN, QTY, PRI, MOA), and so on.

3.5 GS1 Keys as Identifiers

A defining feature of EANCOM is the use of GS1 keys to identify entities in the data elements:

4. GS1 EDI Messages by Business Process

The EANCOM Syntax 3 standard defines the following messages, grouped by business process:

4.1 Master Data

4.2 Ordering

4.3 Transport and Delivery

4.4 Financial

4.5 Report and Planning

4.6 System

5. Key Messages in Detail

5.1 ORDERS — Purchase Order

The most widely used EANCOM message. A buyer sends ORDERS to a supplier to order goods or services.

Key segments:

Example (simplified):

UNB+UNOC:3+5401234567890:14+5098765432109:14+220622:1200+REF001'
UNH+1+ORDERS:D:16B:UN:EAN011'
BGM+220::9+PO-20260622+9'
DTM+137:20260622:102'
NAD+BY+5401234567890::9'
NAD+SE+5098765432109::9'
LIN+1++54012345678901:SRV'
QTY+21:500:PCE'
PRI+AAA:12.50'
MOA+203:6250.00'
LIN+2++54012345678918:SRV'
QTY+21:200:PCE'
PRI+AAA:8.75'
MOA+203:1750.00'
CNT+2:2'
UNT+15+1'
UNZ+1+REF001'

Key point: Each line item ships the GTIN of the product. The buyer and seller are identified by their GLNs in the NAD segments. No textual product descriptions are needed — the GTIN is the master key.

5.2 DESADV — Despatch Advice

The supplier sends DESADV when goods are shipped. It informs the buyer what was shipped, when, how, and on which logistic units.

Key segments:

Example (simplified):

UNB+UNOC:3+5098765432109:14+5401234567890:14+220622:1400+DES002'
UNH+1+DESADV:D:16B:UN:EAN010'
BGM+351::9+DES-20260622-001+9'
DTM+11:20260622:102'
NAD+SF+5098765432109::9'
NAD+ST+5401234567890::9'
RFF+ON+PO-20260622'
CPS+1'
PAC+1+201:::CT'
PCI+33E'
GIN+SSCC+354012345678901234'
CPS+2+1'
PAC+2+201:::CT'
LIN+1++54012345678901:SRV'
QTY+12:500:PCE'
UNT+15+1'
UNZ+1+DES002'

The CPS/PAC/PCI segments describe the packaging hierarchy — which SSCCs contain which GTINs and quantities. This enables the receiver to verify deliveries against SSCC scans.

5.3 RECADV — Receiving Advice

The buyer sends RECADV after receiving and checking the goods. It confirms what was received, what was accepted, and what was rejected or damaged.

Key segments:

5.4 INVOIC — Invoice

The supplier sends INVOIC to bill for goods or services delivered.

Key segments:

5.5 PRICAT — Price/Sales Catalogue

The supplier sends PRICAT to publish their current product catalogue — GTINs, descriptions, prices, and effective dates.

Key segments:

5.6 PARTIN — Party Information

Trading partners exchange PARTIN to share GLNs and party details. This is typically exchanged once (or updated when changes occur) before any transaction messages flow.

Key segments:

6. EDI Communication Protocols

EDI messages must be transported between trading partners. The following protocols are commonly used:

AS2 is the dominant protocol in North American retail. AS4 is increasingly mandated for European healthcare and public procurement. OFTP2 is widely used in the German automotive supply chain.

7. Implementation

7.1 Getting Started

The GS1 implementation roadmap follows these steps:

1. Obtain a GLN for your organisation — this is your identifier in all EDI messages
2. Assign GTINs to your products (GS1 Company Prefix → GTIN allocation)
3. Choose your EDI standard — EANCOM (UN/EDIFACT) or GS1 XML
4. Select a communication protocol — AS2, AS4, OFTP2, or SFTP
5. Set up an EDI translator — commercial or open-source solution that maps between your internal data format and EDI messages
6. Exchange PARTIN with your trading partner to share GLNs and contact details
7. Test and certify — typically an end-to-end test of message pairs (ORDERS ↔ ORDRSP, DESADV ↔ RECADV)
8. Go live — migrate from parallel paper/EDI to live-only EDI

Implementation guidelines are available at gs1.org/ecom-implementation. GS1 recommends working with a GS1 Member Organisation for local support and certification.

7.2 EDI Translator Architecture

ERP/WMS (your internal system)
    |
    v
EDI Translator (maps data / EDI format)
    |
    +-- Outbound: Internal format → EANCOM/XML → send
    +-- Inbound: Receive → EANCOM/XML → Internal format
    |
    v
Communication Adapter (AS2, AS4, SFTP, ...)
    |
    v
Trading Partner (buyer/supplier)

7.3 Best Practices

7.4 Common Pitfalls

8. References

• GS1 EANCOM Standard: https://www.gs1.org/standards/eancom — Official GS1 EANCOM page with specification and message definitions
• How GS1 EANCOM Works: https://www.gs1.org/how-gs1-eancom-works — Business context and benefits of EANCOM
• GS1 EANCOM Syntax 3 (2022): https://www.gs1.org/eancom/syntax-3 — Full message catalogue for UN/EDIFACT D.16B-based edition
• GS1 EANCOM Syntax 4: https://www.gs1.org/standards/edi/eancom — Next-generation EANCOM syntax edition
• GS1 EDI Implementation: https://www.gs1.org/standards/ecom-implementation — Getting started guide and implementation resources
• GS1 EDI Standards Overview: https://www.gs1.org/standards/edi — Full GS1 EDI portfolio including EANCOM and GS1 XML
• GS1 Identification Keys: https://www.gs1.org/id-keys — GTIN, GLN, SSCC and other GS1 key standards
• GTIN (Global Trade Item Number): https://www.gs1.org/standards/id-keys/gtin — GTIN specification and allocation rules
• UN/EDIFACT Standard: https://unece.org/trade/uncefact — United Nations rules for EDI for Administration, Commerce and Transport
• GS1 General Specifications: https://www.gs1.org/genspecs — Barcode and data carrier standards (Capture layer)