Board Lock and Solder Joint Reliability
The FX2CA2-20P-1.27DSAL(71): The board lock — a pair of metal tabs that solder into plated through-holes — takes the shear and peel stress off the signal pins during mating and unmating. Without it, the narrow 1.27 mm pitch leaves little copper pad area to resist the lever force of a cable or another board being plugged in. This is the difference between a joint that lasts through field service and one that cracks after a few cycles.