Abstract: A device for testing the interface to periscope inboard electronics is provided with an enclosure having a cable connector for a plurality of cables from a periscope mast. Each cable includes electric wires, fiber optic lines, radio frequency lines, and video lines. A plurality of interface panels are mounted on the enclosure. Each interface panel is associated with a cable of the plurality of cables. Each interface panel has test points for each voltage conducting cable, video path, and fiber optic line for the associated cable and status indicators for the device and inboard electronics. A multi-position switch is mounted on the enclosure and can be selected for one of a plurality of periscope mast types.