The authors discuss information transmission errors occurring between design engineers involved in software development and describe an interface design documentation system that can prevent them. The equivalence of human errors in software design and hardware manufacturing activities is established. The characteristics that must be included in an interface documentation system to prevent communication errors in software design activities, based on foolproofing principles that were identified for hardware manufacturing, are discussed. Utilizing these characteristics, an example of an interface documentation system for software products which control measuring equipment is presented. Its effects on the resultant number of communication errors between hardware and software engineers is subsequently experimentally evaluated.>