The scope of this standard is to define the services needed to support AI-ESTATE. It provides a formal definition of the encapsulated services that an AI-ESTATE-conformant diagnostic reasoner shall provide to the other elements of the architecture constituting an AI-ESTATE-conformant system. The services defined in this standard are applicable to the domain of system test and diagnosis, independent of the reasoning approach. The purpose of this component standard is to provide the formal specifications of the services, transactions, and protocols necessary to insure the interoperability of AI-ESTATE compliant systems. It provides a formal specification of the encapsulated services required of a diagnostic reasoner, which directs system test and diagnosis, and ensures the interchangeability of diagnostic reasoners within AI-ESTATE-conformant systems. This standard will specify the services required of a diagnostic reasoner by the other architectural components of an AI-ESTATE-conformant system. New IEEE Standard - Superseded. Formal software interfaces to system diagnosis tools and applications are defined. As part of the AI-ESTATE set of standards, this standard defines services to manipulate information models as defined in IEEE Std 1232.1-1997 and to control a diagnostic reasoner. This standard includes a new information model to manipulate dynamic information obtained during the process of system diagnosis. Service bindings to ANSI C and ANSI Ada are also provided.