Abstract: In a launcher control system (12), a missile interface unit (29) for controlling a ground launched active radar guided missile (GLA) which is modular in construction. The missile interface unit (29) provides target position information and control signals for test and launch of the GLA, and power for activating the GLA, as well as determining the status of the GLA. It employs a plurality of cards (56-70), each card having a specific function and being interconnected by a backplane bus system (55) which also couples the cards (56-70) to other components of the launcher control system (12).