ACKNOWLEDGEMENT

Receipt acknowledgment. Any return from a receiver to an EDI sender — the concept comes in three levels you must not conflate.

Definition

In EDI, the term acknowledgement covers three very distinct families that implementers often confuse:

1. Transport acknowledgement: returned by the transport layer — e.g. a signed AS2 MDN, a signed OFTP2 EERP, an AS4 SOAP receipt. Attests that the receiver received the bytes. Says nothing about conformance or content.
2. Syntactic acknowledgement: returned by the EDI parser — e.g. a CONTRL in EDIFACT, a 997/999 in X12. Attests that the segments conform to the ISO 9735 or X12.5 syntax and that envelope references match. Says nothing about business content.
3. Business acknowledgement: returned by the application — e.g. an ORDRSP in EDIFACT (Purchase Order Response), an 855 in X12 (PO Acknowledgment), an APERAK for business return codes. Attests that the application has accepted or rejected lines for business reasons (invalid price, unknown GLN, quantity above contract).

A robust EDI implementation requires all three: a file that passes AS2, passes CONTRL, and comes back ORDRSP with an accepted code is safely integrated. If any one is missing, the operation remains uncertain.

Origin

The technical/syntactic/business distinction is documented in the earliest UN/CEFACT and ANSI ASC X12 publications of the mid-1980s. Practice has institutionalised: in B2B retail, the DESADV/CONTRL/ORDRSP triplet is contractually required by all major European retailers (Carrefour, Auchan, Casino, Tesco, Edeka, Rewe, Migros). On the US healthcare HIPAA side, the 999 (enhanced functional ack) has been required since 2012 for 270/271/834/835/837 transactions.

Example in context

Full EDIFACT order chain:

1. Buyer sends ORDERS via AS2 — the receiver returns a signed MDN.
2. The receiver's parser validates syntax, returns a CONTRL UCI/UCM all OK.
3. The receiver's application validates the lines, returns an ORDRSP with a 4221 acceptance code on each LIN (29 Accepted, 31 Accepted with modification, 27 Rejected).
4. The buyer closes its control loop once the three acknowledgments are in.

Related terms

• CONTRL — the EDIFACT syntactic acknowledgement.
• Functional Acknowledgement — the X12 syntactic ack (997/999).
• MDN — the AS2 transport ack.
• ORDRSP — the EDIFACT business ack of an order.
• Non-repudiation — property granted by a signed acknowledgement.