I know it's strange, but it's like that. You receive their card, and you need to use it in their own set-top-box (which you need to buy or rent). Even more, you cannot even swap your card into the decoder of eg. your neighbour which uses the exact same set-top-box (because, as said, telenet's the only cable provider in Belgium), that also doesn't work. They do this like so because you can subscribe to more digital channels. If the card would be swappable between set-top-boxes, you could 'rent' your card to your neighbour if you wanted to. That's their explanation at least, which I find total BS BTW.