Yes, it depends on your settings of the router. Today's N routers can be set to allow B, G, N and almost any combination so if you decided to only allow N clients, that's your choice.
I have a question that applies both to this router specifically and to N routers in general.
Background info - Just bought a wifi enabled bluray player and need to upgrade routers for streaming video (previous on is a g router that's 7 years old).
The question - Will this (or any other 802.11 n router) work with older devices (ones which were purchased when 802.11 g was the standard)?
This router research is incredibly confusing, so any help would be greatly appreciated.