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.

Nagravision CAMs are famous for their BoxKey, in the multi-satellite world, when Nagravision is one of the few systems around where the smart card is mated to the CAM. This means that the CAM will expect to see a matching BoxKey value when the card is inserted or else the card may not work and will generate an error message instead.

So before you can use card and CAM together then they will need to be mated. Subscribers can often do this by telling their service provider their CAM's serial number. Another possibility is that the brand new subscription card will lock on to the first BoxKey that it sees. And for other people then you will need to convert this serial BoxKey value into the Hex version (just use a calculator) and then make sure that your card contains this Hex value BoxKey.

So once the card and CAM are mated then your system should work not unlike any other with the exception that you cannot then use this card in a different CAM. Well that is if your service provider is making full use of the Nagravision card mating system when they may also ignore it instead.