A set-top box (STB) is an electronic device that enables a TV set to receive and decode digital television (DTV) broadcasts. It is also known as a cable box, receiver, or television decoder. The device converts video content to analog or digital TV signals. The primary purpose of a set-top box is to stream movies and television series, and it allows users to view video content from specific internet video providers via the internet. It is necessary for viewers who want to use their analog television sets to receive digital broadcasts. Set-top boxes also enable closed captioning on older sets in North America, before this became a mandated inclusion in new TV sets. Some set-top boxes include a V-chip that allows only programs of some television content ratings. Hybrid set-top boxes, such as those used for Smart TV programming, enable viewers to access multiple TV delivery methods (including terrestrial, cable, internet, and satellite).