To indicate the start of a transaction set and to assign a control number
Code identifying a Transaction Set
The transaction set identifier (ST01) is used by the translation routines of the interchange partners to select the appropriate transaction set definition (e.g., 810 selects the Invoice Transaction Set).
Identifying control number that must be unique within the transaction set functional group assigned by the originator for a transaction set
Reference assigned to identify Implementation Convention
The implementation convention reference (ST03) is used by the translation routines of the interchange partners to select the appropriate implementation convention to match the transaction set definition. When used, this implementation convention reference takes precedence over the implementation reference specified in the GS08.
