what is interface control document
(Redirected from Interface Control Document). An interface control drawing or interface control document (ICD) in systems engineering and software engineering, describes the interface or interfaces between subsystems or to a system or subsystem.n application programming interface is a form of ICD for a software system, in that it describes how to access the functions and services provided by a system via an interface. If a system producer wants others to be able to use the system, an ICD (or equivalent) is a worthwhile investment.