It belongs to the standard-density HD-20 series, which is the workhorse D-sub line for industrial control panels, test equipment, and serial communication ports where a reliable signal interconnect is needed. The 2 A per contact rating and 250VAC voltage rating place it firmly in signal-level duty — think RS-232, instrumentation links, or low-current I/O — not power distribution.
Board Locks and Right-Angle Mounting
Without them, the solder joints take the full mechanical load every time the mating plug is inserted or removed. The 0.411" (10.43mm) backset spacing gives clearance behind the mounting flange for the PCB edge.