Abstract: A flexible DUT interface assembly is presented. The DUT interface assembly includes a DUT interface board with a plurality of slots to accommodate inserted circuit cards for providing a plurality of different test functions, a socket adapter card to accommodate a plurality of DUTs via a plurality of sockets and to provide the interface between the DUTs and the DUT interface board, and an interposer to provide the required space for the inserted circuit cards between the DUT interface board and a test head module. The modular characteristics of the assembly parts (i.e., DUT interface board, socket adapter, and interposer) and their sub-components allows configuration (e.g., DUTs, test functions, etc.) and repair to be rapidly and easily carried out. The interposer allows external environmental factors around close-coupled instruments, such as temperature, humidity, and electrical noise, to be easily monitored and controlled.