The 031-5538-10RFX: It's the kind of connector you see on test equipment, RF distribution panels, and instrumentation where a quick, secure bayonet mate is the norm. The right-angle PCB tail and front-side nut bulkhead mount let you land the signal perpendicular to the board and lock it against the panel face — handy when the enclosure wall is the strain relief.
Mounting Hardware and What Comes in the Box
The lockwasher and nut are the front-side mounting hardware for the bulkhead — you don't need to chase down a separate hardware kit for the panel install.
Mating Cycles and Field Service
The bayonet lock gives a positive engagement that resists vibration better than a push-pull, and the gold-plated center contact on phosphor bronze handles the repeated wipe without fretting. The polypropylene dielectric keeps the impedance stable through the cycles.
The 31-5640-1010 is the closest functional peer — same BNC jack, same 50 Ohm, 1 GHz, 500 V, same zinc die-cast nickel body, same bayonet lock, same gold center contact. The difference is the 031-5538-10RFX carries the 'Isolated' feature and comes in a black/silver housing, while the 31-5640-1010 is silver only and lacks the isolated designation. If your application needs the isolation or the black insulator, this is the one; otherwise the 31-5640-1010 is a drop-in for the footprint and electricals.