A mounting plate having at least two L-shaped mounting flanges alternatively offset from a centerline defined to bisect the mounting flanges. A mounting system including a plurality of mounting plates with interlocking mounting flanges positioned horizontally on a mounting frame of one standard rack unit (1.75 inches) height. A mounting system including a plurality of mounting footprints with overlapping fastener flanges positioned horizontally on a mounting frame of one standard rack unit width. A method of mounting plates configured and dimensioned to receive a fiber optic coupler or adapter including a mounting a plurality of plates having at least two L-shaped mounting flanges into a mounting frame such that the mounting flanges of adjacent plates are configured to interlock or overlap.