Thanks for the very useful explanation, it clears up a lot of stuff.
However, being the noob that I am, I still don't understand the following:
I have a sat subscription but the receiver provided by the operator is quite weak (ok, it's crap).
I just bought a new hd receiver and thought that I could just use the card in the new receiver and that would be that (I knew beforehand that the card was not paired to the box). However this is not the case, I still had to install CCcam to be able to read my card on the new receiver. I don't quite understand why... Someone care to explain?
Also, I read that CCcam is an emulator; what is it emulating?
