Why do many subscription agreements oblige a subscriber to use a STB made available by the satellite, cable, terrestrial or IPTV company?
In order to guarantee the quality and integrity of the service to their subscribers, service providers will often specify the features and fundamental specifications of STBs. In particular these will include conditional access for content protection (and to ensure the subscriber receives the services to which he is entitled) and middleware for interactive services which allows differentiation between service providers. Service providers may choose the manufacturers who make the STBs or allow any manufacturer to do so, subject to them complying with the required features. STBs can be made available directly from the service provider or in retail outlets. Whilst normally a STB is linked to a subscription some service providers allow the STBs to be solely for free to air viewing.
