The Institute for Electrical and Electronics Engineers (IEEE), through its Standards Coordinating Committee 20 (SCC20), is developing interface standards focusing on Automatic Test System-related elements in cooperation with a Department of Defense (DoD) initiative to define, demonstrate, and mandate such standards. One of these standards-IEEE Std 1232-2002 Artificial Intelligence Exchange and Service Tie to All Test Environments (AI-ESTATE)-has been chosen for demonstration prior to mandate. In this paper, we discuss the results of the first phase of the AI-ESTATE demonstration, focusing on semantic interoperability of diagnostic models. The results of this demonstration successfully showed the effectiveness of semantic modeling in information exchange. In addition, the engineering burden was demonstrated to be manageable: all applications were constructed in less than four months by three graduate students working part time. 1,2 TABLE OF CONTENTS 1. INTRODUCTION.