Two frameworks, one goal

Every outbound EDI message starts as a decision inside the application: this sales order needs a confirmation, this delivery needs a ship notice, this invoice needs to go to the customer. That decision is called output determination. It answers what to send, to whom, through which channel and when. Only after it has produced an output does the IDoc interface (course sap-edi-201) build and send the IDoc. So when Maria asks why Great Lakes Fleet Services did not get an 855 for sales order 1000457, the first question is not about ports or middleware. It is whether output determination produced an EDI output at all.

SAP S/4HANA has two frameworks for this, and a converted system like Contoso's uses both.

Classic message control

Message control, also called output determination or NAST after its main table, has run SAP output since R/3. It uses the same condition technique as pricing: an output determination procedure lists output types; each output type has an access sequence; each access reads condition tables; and condition records say, for a given key such as sales organization and customer, which partner function, medium and dispatch time to use. For EDI the medium is 6 (EDI), and the processing routine for that medium hands the output to the IDoc interface, which finds the partner profile and builds the IDoc.

SAP S/4HANA output control

SAP S/4HANA output control (often called output management) determines output with business rules in decision tables, maintained in the Output Parameter Determination app. For each business application it runs determination steps in order, including output type, receiver, channel, printer or email settings, form template and output relevance. SAP Learning describes it as the successor to the earlier frameworks. For electronic messages, SAP's documentation is precise: output control supports the channels IDOC, XML and EDI; the IDOC channel is designed for intercompany billing only; the EDI channel, available since 2019, is the default for electronic communication with business receivers and supports IDoc and SOA (XML) formats depending on the application; and output control does not handle system integration such as ALE.

Which one does a document use?

The choice is made per application object type (for example SALES_DOCUMENT, BILLING_DOCUMENT or PURCHASE_ORDER) in Customizing under Cross-Application Components > Output Control > Manage Application Object Type Activation, where each object is either left at its default or set to "Application Inactive" so that NAST is used. The defaults differ by object and by source: SAP's billing documentation states that output control is active for billing documents after a conversion, while SAP Learning's purchasing course says NAST remains the default on premise and recommends that converted systems keep their existing NAST setup. Never assume; open the activity in the system you are testing.

Why does this matter for testing? Because the two frameworks fail differently. A NAST problem usually shows up as a missing or red output line on the document, with a processing log and a determination analysis to explain it. An output control problem shows up as a missing or stuck output item, explained by the rules in OPD and the item's log. A tester who knows which framework a document uses goes straight to the right screen; a tester who does not wastes the first hour of every defect.