The standard defines formal specifications for supporting system diagnosis. These specifications support the exchange and processing of diagnostic information, and the control of diagnostic processes. Diagnostic processes include, but are not limited to, testability analysis, diagnosability assessment, diagnostic reasoning, maintenance support and diagnostic maturation. This standard provides formal models of diagnostic information to ensure unambiguous access to and understanding of the information supporting system test and diagnosis. The standard unifies and expands upon the specifications published in IEEE Std 1232-1995, IEEE Std 1232.1-1997, and IEEE Std 1232.2-1998. Revision Standard - Superseded. Superseded by IEC/IEEE 62243-2005. AI-ESTATE is a set of specifications for data interchange and for standard services for the test and diagnostic environment. The purpose of AI-ESTATE is to standardize interfaces between functional elements of an intelligent diagnostic reasoner and representations of diagnostic knowledge and data for use by such diagnostic reasoners. Formal information models are defined to form the basis for a format to facilitate exchange of persistent diagnostic information between two reasoners, and also to provide a formal typing system for diagnostic services. This standard then defines the services to manipulate diagnostic information and to control a diagnostic reasoner.