Description for EDI Envelope Structure

The envelope structure hierarchy is as follows:

  • UNA: Service String Advice (Optional)
  • UNB: Interchange Header
    • UNG: Functional Group Header (Optional)
      • UNH: Message Header
        • Data Segments
      • UNT: Message Trailer
      • … Additional UNH - UNT pairs
    • UNE: Functional Group Trailer (Optional)
    • UNG: Functional Group Header (Optional)
    • … One or more UNH - UNT pairs
    • UNE: Functional Group Trailer (Optional)
  • UNZ: Interchange Trailer