Usb keyboard for nexus tablet

I tried hooking up a physical keyboard to a nexus 7 or nexus 10, but without a special cable, I tried using a usb hub and normal charging cables. It seems like it should have worked, but it didn't. I tried fiddling with settings on the nexus and rooting it, but couldn't get a physical keyboard to be recognized. I saw some posts that made it appear that other people had made it work, so I tried ordering a specialty adapter cable to go directly to the nexus without a usb hub. That worked.

The part that did the trick for me was:

Adelle Inc
1204 Avenue U, Ste #2029
Brooklyn, NY 11229
NQ-R6S9-R832
eForCity Micro USB OTG to USB 2.0 Adapter compatible with Google Nexus 7
$3.10