Segment: ST Transaction Set Header Position: 010 Loop: Level: Heading Usage: Mandatory Max Use: 1 Purpose: To indicate the start of a transaction set and to assign a control number Syntax Notes: Semantic Notes: 1 The transaction set identifier (ST01) is used by the translation routines of the interchange partners to select the appropriate transaction set definition (e.g., 850 selects the Purchase Order Transaction Set and the 810 selects the Invoice Transaction Set). Comments: Notes:   Example: ST*855*0012|     Data Element Summary                                                          Ref. Data   Des. Element Name Attributes M ST01 143 Transaction Set Identifier Code M ID 3/3   Code uniquely identifying a Transaction Set       855    Purchase Order Acknowledgment   M ST02 329 Transaction Set Control Number M AN 4/9   Identifying control number that must be unique within the transaction set functional group assigned by the originator for a transaction set     The data interchange control number must be identical to the same data element in the associated transaction set trailer, SE02.   Previous Up Next                   855I4010 (004010) November 3, 1999