In ANSI X12, each type of document has its own transaction set with a defined list of segments, which of them are required and in what order. The three-digit code tells the receiving system what it is reading. The equivalent in EDIFACT is called a message and uses a name instead of a number, such as ORDERS or INVOIC.
Each transaction set starts with an ST segment and ends with an SE segment, which carries a count of the segments included. Related transaction sets are grouped in a functional group (GS/GE), and groups travel inside an interchange envelope (ISA/IEA). The receiver confirms each functional group with a functional acknowledgment. Common supply chain transaction sets include:
- 850 purchase order and 855 purchase order acknowledgment
- 860 purchase order change request (buyer initiated) and 865 purchase order change acknowledgment/request (seller initiated)
- 856 ship notice/manifest and 810 invoice
- 820 payment order/remittance advice and 832 price/sales catalog
- 204 motor carrier load tender, 214 shipment status and 210 freight invoice
- 940 warehouse shipping order and 945 warehouse shipping advice
Knowing the codes is the easy part. Each trading partner can use a different version and its own implementation guide, so the same 856 can look different from one retailer to the next. Supporting a new transaction set with a trading partner means mapping, testing and certification before it can go live.