Interface control document

An interface control document, commonly identified by the acronym ICD, is a technical document used to record, define and control interface information between systems, subsystems, equipment, hardware components or software components.

In systems engineering, an interface can be understood as a shared boundary between functional units, defined by characteristics related to functions, physical exchanges of signals and other technical attributes. The control of such interfaces is relevant in projects in which different parts of a system need to be developed, integrated, tested and maintained in a compatible way.

An ICD is used mainly in contexts where the integration of technical elements requires a precise definition of shared information. This information may include signals, messages, data formats, communication protocols, physical characteristics, compatibility requirements and responsibilities between the parties involved. For this reason, this type of document is associated with integration, verification, validation, configuration management and change control activities in engineering projects.