[Milsurplus] Save me the effort

[CL in NC]

The SCR 522 installed in B17's, was mounted on a wooden shelf in the ball turret section, near the bulkhead where  IFF and PE73 for the BC375, and next to the BC375 trailing wire antenna reel.  Some pics show a junction box mounted vertically on the side of the frame holding the SCR522, some don't.  Does anyone know what the junction box was combining??  Did some B17's have dual controls for it like the RDF had?

Charlie, W4MEC in NC