Comparison of EDI envelopes (X12, EDIFACT and Tradacoms)

Aspect	X12	EDIFACT	Tradacoms
Hierarchy Levels	3 Levels: Interchange, Functional Group, Transaction Set	3 Levels: Interchange, Functional Group (optional), Message	3 Levels: Transmission, Batch, Message
Interchange Header	ISA (Interchange Control Header)	UNB (Interchange Header)	STX (Start of Transmission)
Interchange Trailer	IEA (Interchange Control Trailer)	UNZ (Interchange Trailer)	END (End of Transmission)
Functional Group Header	GS (Group Header)	UNG (Group Header, optional)	BAT (Batch Header)
Functional Group Trailer	GE (Group Trailer)	UNE (Group Trailer, optional)	EOB (End of Batch)
Message Header	ST (Transaction Set Header)	UNH (Message Header)	MHD (Message Header)
Message Trailer	SE (Transaction Set Trailer)	UNT (Message Trailer)	MTR (Message Trailer)
Envelope Flexibility	Fixed, strict hierarchy	Flexible, group header optional	Simpler and flatter hierarchy
Control Numbers	ISA/IEA, GS/GE, ST/SE control numbers for tracking	UNB/UNZ and UNH/UNT control numbers	STX/END and MHD/MTR identifiers
Data Format	ASCII	ISO 9735	Fixed-width ASCII
Regions of Use	Primarily North America	Global (Europe, Asia, and others)	Primarily UK and retail industries
Main Applications	Retail, healthcare, supply chain	International trade, shipping, logistics	Retail and grocery sectors
Validation	Comprehensive control number validation	Message-level validation	Batch-level validation
Complexity	Moderate complexity, widely adopted	High complexity, globally scalable	Simple structure, industry-specific