Example of an ANSI ASC X12 Message Structure

 

Here’s a simplified example of a Purchase Order (850) document:

ISA*00*          *00*          *ZZ*SENDERID       *ZZ*RECEIVERID     *210707*1234*U*00401*000000001*0*P*>
GS*PO*SENDERID*RECEIVERID*20210707*1234*1*X*004010
ST*850*0001
BEG*00*SA*123456789**20210707
REF*DP*038
N1*ST*ACME INDUSTRIES*92*12345
PO1*1*100*EA*9.99**BP*123456
CTT*1
SE*8*0001
GE*1*1
IEA*1*000000001

• ISA (Interchange Control Header): Identifies the start of the interchange and contains sender/receiver information.
• GS (Functional Group Header): Groups related transaction sets.
• ST (Transaction Set Header): Indicates the start of a transaction set.
• BEG (Beginning Segment for Purchase Order): Contains information specific to the purchase order.
• REF (Reference): Includes references such as order numbers.
• N1 Loop (Name and Address): Identifies the buyer.
• PO1 (Purchase Order Line Item): Details each line item in the purchase order.
• CTT (Transaction Totals): Summary of the transaction.
• SE (Transaction Set Trailer): Indicates the end of the transaction set.
• GE (Functional Group Trailer): Indicates the end of the functional group.
• IEA (Interchange Control Trailer): Indicates the end of the interchange.