Control Numbers

The X12 standard includes a control number for each enveloping layer, as follows:

• ISA13: Interchange

• GS06: Functional Group

• ST02: Transaction Set

The control numbers act as identifiers. These numbers are used for message identification and tracking. eXchange includes a flag for each control number. This feature allows you to choose not to assign control numbers to outgoing messages and not to store control numbers on incoming messages.

The remainder of this section provides a brief explanation of each of these control numbers’ usage.

ISA13 (Interchange)

The ISA13 control number is assigned by the message sender. It must be unique for each interchange. This is the primary means used by eXchange Integrator to identify an individual interchange.

GS06 (Functional Group)

The GS06 control number is assigned by the sender. It must be unique within the Functional Group assigned by the originator for a Transaction Set.

eXchange ensures that the Functional Group control number GS06 in the header must be identical to the same data element in the associated Functional Group trailer, GE02.

ST02 (Transaction Set)

The ST02 control number is assigned by the sender and is stored in the Transaction Set header. It must be unique within the Functional Group.

eXchange ensures that the control number in ST02 is identical with the SE02 element in the Transaction Set trailer and is unique within a Functional Group (GS-GE). Once you have defined a value for ST02, eXchange always uses that same value for SE02.