can anyone explain me the application of a Cable set top box?

Question

There are other STBs like IP, satellite, terrestrial. I can be happy with the application of the basic Cable one. The way it works, why it is useful.

Answer 1

A basic cable box has a cable tuner and software or a card that allows you to see scrambled cable channels.
(TVs have cable tuners, but you can't see scrambled channels without a special Cablecard)
More advanced boxes connect to the phone line so you can order pay per view movies
There is the option to get a set-top box with a hard disc (PVR).