In the early stages of military infrared technology development, common modules were formed by standardizing the key components of thermal imaging systems in Europe and America. These common modules decreased the scope of choice between different technical proposals. However, it reduced the costs of researching, developing, operating, and maintaining infrared systems, and was beneficial to mass production. The SADA-series assembly was established in America based on the first-generation common module. The implementation of the horizontal technology integration (HTI) program based on the SADA assembly met the requirements of mass production and equipment for military thermal imaging. In this paper, the history and status of the common module in Europe and America is introduced. Common modules have become critical to the advancement of detector, microelectronics, and other related technologies.