X12 envelopes

An X12 file is organized in several nested envelopes, which are pairs composed of header and trailer segments:

• Interchange envelope (ISA and IEA segments)
  • Sender + Receiver
• Functional Group envelope (GS and GE segments)
  • Sender + Receiver + Transaction type
• Transaction Set envelope (ST and SE segments)
  • Transaction type
  • Contains Transaction details

An X12 file can contain several envelopes.

Interchange envelope

The Interchange envelope is composed of ISA and IEA segments. It also contains:

• Sender identification with ISA ID Qualifier and ISA ID
• Receiver identification with ISA ID Qualifier and ISA ID
• Transaction identification with interchange control number

Functional Group envelope

The Functional Group envelope is composed of GS and GE segments. It also contains:

• Functional Identifier Code (Transaction Type)
• Sender’s Code
• Receiver’s Code
• Group Control Number

Transaction Set envelope

The Transaction Set envelope is composed of the ST and SE segments. It also contains:

• Transaction Identifier Code (Transaction Type)
• Transaction Control Number