Why Promptlink Automated STB Solution is Right for You - The set-top box (STB), also known as a cable box in layman's terms, is one of the most important pieces of hardware for any person setting up a home cable or satellite television system. The STB serves to receive, interpret, as well as decode digital images on a television screen. When a user switches to his or her favorite television channel, the STB filters through all the signals being received to find the appropriate signals for the requested channel or service; this is then displayed on the television set.