The TE Connectivity 5750678-1 is a 9-position D-Sub receptacle from the AMPLIMITE HD-20 series, with a DE-9 shell size — the standard layout for RS-232 serial ports and similar signal interfaces. It mounts vertically through the PCB and terminates via solder tails, accepting the matching male D-Sub plug with 4-40 screwlocks for a vibration-resistant mate.
Board locks and what they do on the assembly line
Without them, the connector can shift from the cable insertion force, and the solder joints on the outer pins take the shear. The board locks keep the alignment through reflow and resist the strain from a mated cable bundle in a panel or enclosure.