Don:
From the SkyView System Installation Guide, Rev R, page 15-16:
The Video Input Adapter includes various connectors for multiple input sources, but in SkyView, only the Composite Video (the middle cable in the illustration at right – Yellow, single RCA connector) and the SVideo (the left cable in the illustration at
right left, 4-pin mini-DIN) inputs are functional.
So, yes, you're correct, we don't make reference to that particular connector because it doesn't do anything in SkyView.
Did all that. There is a receptacle on the end of the black box, no idea what it is for, never seems to be mentioned.