RJ45 Jack for Cat3 Ethernet — Vertical Through-Hole with Board Locks
The Molex 0428788506 is an 8p8c (RJ45, Ethernet) jack from the 42878 series, wired for Cat3 performance. It carries 8 positions and 8 contacts in a single-row vertical orientation, terminated by through-hole solder. Board locks on the housing hold the jack steady during wave solder and take the shear load from repeated cable insertion and strain at the panel face.
This jack is rated Cat3, which limits its usable frequency to 16 MHz. That makes it a fit for 10BASE-T and 100BASE-T4 Ethernet, or for POTS/analog phone lines running over the same RJ45 form factor. The 8p8c pinout is standard RJ45, so the mechanical mate is the same; the difference is in the signal integrity the twisted-pair cabling can deliver through this connector.
Board Locks and Vertical Mount — Installation Context
The vertical orientation means the RJ45 plug inserts perpendicular to the PCB — typical for edge-mounted ports on a network interface card, a wall-plate PCB, or an industrial control board where the cable enters from above. The board locks (two metal tabs that solder into plated through-holes) anchor the jack against the push-pull force of a patch cable. Without them, the solder joints on the signal pins take the full mechanical load and eventually crack.