Cable Fit — Belden 4731R and 4731P
The 031-70560-12G: This plug is dimensionally matched to Belden 4731R and 4731P cables — the ferrule ID and center contact pin diameter are cut for those specific jacket and dielectric diameters. Using it on a different 75 Ohm cable (e.g., Belden 1855A or 4694R) will not crimp correctly and will likely degrade the impedance match or pull-out strength.
75 Ohm vs 50 Ohm — Why It Matters
The 75 Ohm impedance is standard for video, broadcast, and SDI signal paths — HD-SDI runs at 75 Ohm. A 75 Ohm plug on a 50 Ohm jack will mate physically (same bayonet lock) but the impedance mismatch will cause signal reflections above a few hundred MHz. The 12 GHz frequency rating only holds when both the plug and the mating jack are 75 Ohm.
Crimp Termination and Field Assembly
The center contact crimps onto the cable's center conductor; the ferrule crimps over the braid and jacket. No solder, no clamp — just a standard hex crimp tool with the correct die for Belden 4731R/P.