Segment group

The Segment group type in the Control category represents the envelope segments. Envelope segments are used:

To surround functional groups within an ANSI X12 interchange, the ISA, and IEA segments in X12.
For interchange acknowledgments, the TA1 segment.
To specify interchange delivery and handling requirements, the ISB, and ISE segments.

Each Segment envelope type begins with a set of letters that identifies the segment, for example IEA. These same sets of letters (IEA) are also used in the Properties window of the Type Designer to define the value of the initiator.