USB extender cable with notch

[xtempo]

I found what appears to be an extension USB cable but I can't plug any thing into it as there is a notch in the female end. I've not been able to take any good pictures but this one seems the best.
any ideas what this was used for?

 

[satinsilverem2]

its the extension cable that came with the wired versions of the Apple Keyboard. Judging by the way the connectors looks its from a pre 2007 keyboard. they are standard cables with just a notch. I just filed the notch down or crimped it with a pair of pliers to make it a usable cable.

 

[xtempo]

thanks