International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The US Government originally funded the development of the Common Airborne Instrumentation System (CAIS) to address industry-wide compatibility, maintenance, and commonality issues. Although initially targeted for US Department of Defense (DoD) programs, CAIS is also being used throughout the world in many commercial applications. This paper provides a fresh look at the evolution of the CAIS concept starting with some historical background of the CAIS Program, an overview of the CAIS System Architecture and recent trends in the use of “Commercial Off The Shelf (COTS)” products and technology.