I have a Bluetooth USB adapter from MediaLink [originally bought for my desktop PC to give it Bluetooth capability). On my Samsung Galaxy Tab (Wifi only) I can plug it in [with the use of a Samsung adapter, yes--an adapter for an adapter] (and of course if I do so, I can't charge the tablet). Its blue LED light comes on when I plug it in (so I know it's getting power), but I can't find any way to have it "supercede/override" the built in Bluetooth capability of my tablet (in fact I can't even find a way to tell what version of Bluetooth my tablet is running [using Settings, etc.,]. I put a great deal of time into this via the usual trial and error to find a workaround.
So unless someone tells me how to get my tablet to recognize the adapter, I'm at a dead end with it [by the way it works fine on my PC desktop]. While I'm at it, I would like to be able to upgrade my tablet's Bluetooth to Ver 4, and I haven't found any way of getting the drivers for that either (even if I could get the adapter to be recognized)---upgrading to Ver 4 was the whole point of my efforts.