Where is the ground connection on the RCP itself?

[alangbaker]

I was looking at the wiring instructions for the CoilX:

http://www.autosportlabs.net/CoilX

And it shows a "Ground" on the "To RaceCapture/Pro" box.

So where is it? Do I need to make up an RJ45 pigtail, because that's the only place I see a ground listed on the quick reference diagram?

[gizmodo]

I tied it into the negative terminal on the RCP.