Glossary · System coordination, integration and orchestration
Interface definition
Also known as: interface description
German: Schnittstellendefinition
In systems engineering and integration, an interface definition is the description of an interface between two systems or components, stating the exchanged data, signals or services, their formats, timing, protocols and the behavior expected from each side.
- System integration
- Technical documentation
In one sentence
An interface definition describes what two systems exchange across an interface: data, signals, formats, timing, protocols and expected behavior.
Example
The interface definition between filler and capper lists twelve signals with addresses, data types, meanings, timing and the reaction to communication loss.
How it applies
- Engineering: Define interfaces early and from both sides. An interface definition should cover normal operation, error cases, start-up and restart, not only the list of signals.
- Change: Interface definitions are shared agreements. Put them under version control and change them only with the agreement of both sides.
- Documentation: Technical writers can help make interface definitions unambiguous: consistent terms, one meaning per signal name, tables instead of prose for signal lists, and diagrams for sequences. Machine-readable formats, such as OpenAPI for web APIs or OPC UA information models, allow documentation to be generated and checked.
Interface definition vs. interface specification
The terms are often used interchangeably. Where both exist, the interface definition is the description of the interface content, while an Interface specification or Interface control document (ICD) is the formally controlled document that contains it and states requirements.