When the channels are sent to you through satellite/digital cable, they are all sent in scrambled form. Whatever channels you have access to are then descrambled at the box, through another signal running along side the channels. A descrambler will send a virtual descramble signal through the box, thus descrambling the channels. Also, it will stop any PPV orders from being sent out, so you basically get the movies for free. Although, on satellite, you usually have to remove the phone line from the back for this. And trust me, never plug the phone line back in. It will send all unsent orders through to PPV.

I DONT WANT A SIG!!!!
Your REALLY gonna want to click this