Framework EDI Reference. SEFManager Utility
.SEGS Section

The .SEGS section lists all the data segments that are implemented in the version of the EDI standard.  The list is not always in alphabetical order.  In some implementation not all the data segments of the version are listed, and only those data segments that are implemented in the transaction sets or message listed in the same SEF file are defined.  It is recommended that all data segments should be listed so that if additional segments are required in other sections, the definition for those data segments already exist.

The EDI standard define the data segments as consisting of data elements and/or composite elements, and so, in following that line, the SEF file displays them in that way.  Each data segment definition is followed by an ordered list data elements and/or composite elements that makes it.  Example,

AAA=[1073,M][559][901][889]
 

which means that data segment with ID "AAA" is made up of data elements with the following IDs: "1073", "559", "901" and "889".  The order in which the data elements and composite elements occur in the data segment is crucial because their position corresponds to the position of the actual values of the data segment in the document.