Second Power Connector on older PSUs? (Just Curious)

MceraWV

Honorable
Jan 29, 2016
28
0
10,540
Hello all,

From my time in working on computers, both new and old, I've seen PSUs with what appears to be a second form of AC power connector, in addition to the standard universal 3-pronged one that plugs into the wall (the other connector circled in red in this image: http://i.imgur.com/CXRj1CK.jpg ). It looks like it's identical to the female version of the PSU power cable ( http://cdn.overclock.net/d/dc/350x700px-LL-dcd2a813_10w1-012.jpeg ) but I have absolutely no idea what it is, and have not been able to find an explanation on it.

I've been curious as to what this connector is/was used for, and would be happy with any explanation regarding its purpose!
-MC