Some cable systems rely on the fact that they can use frequencies over the cable
which are not permitted for over-the-air broadcast use, and which cannot be received on an ordinary receiver.
This a cable company might transmit premium programs on a different frequency beloew the normal television
band, and provide subscribers to the service with a descrambler, which is just a frequency convertor, which
will provide the proper output frequency suitable for use with a normal television receiver. The risk with
this method is that viewers may be able to get ahold of multi-band receivers which could tune directly to
the cable frequency, thus being able to receive the service.
