What is a Digital TV Descrambler?
A digital TV descrambler is a device, usually built into a set top box, which decodes encrypted channels. This allows customers to watch subscription-based channels or pay-per-view events. Usually the television service supplier will give subscribers a smartcard which allows the descrambler to work for the duration of their subscription. Some independent traders offer unofficial descramblers designed to allow viewers to watch subscription channels without paying, though this is both illegal and unreliable. Descramblers can be used in both satellite and cable systems. In some countries, they are also used with digital terrestrial broadcasting: that is, digital channels broadcast over the air and received with a standard TV aerial. While some countries have all digital terrestrial broadcasts available without charge, other countries have systems where some premium channels are scrambled as with cable or satellite.