Android bluetooth what is the difference between linked and paired

I am busy with android project in eclipse to connect samsung galaxy s4 with bluetooth to random other bluetooth device. I want to start with HTC incredible.

My question is what is the difference between linked and paired. As android says it is the same but in my application they don't act the same.

I have red when you start Discovery (). you can see all paired devices. this works fine, but if i call device.getBondState (); then it means that the device is not connected.

And if the device is not connected, I cannot connect to the device.