External keyboard for Galaxy tablet 2 7.0

I'm trying to use an external keyboard with my Galaxy tablet 2 7.0. My tablet isn't detecting the keyboard, but it works when I plug it into my computer. This keyboard uses a normal USB male to connect, but my tablet uses samsung 30-pin to male. So, I bought a female-to-female adapter. I'm assuming this is the equivalent of a USB OTG adapter but still no joy. How do I get this keyboard to work?