Recommendation ITU-T H.721 describes and specifies the functionalities of the IPTV terminal devices for the IPTV basic services defined in Recommendation ITU-T H.720. This Recommendation is targeted at IPTV terminal devices capable of receiving linear TV service and video-on-demand services, with additional data content (such as text) using a managed content delivery network. The service definition takes into consideration conditions on content delivery such as QoS. The expected types of IPTV terminal devices are set-top boxes and digital TV sets with embedded IPTV capabilities.

Amendment 1 introduces new Appendix II, which describes implementation examples that support ITU-T H.721 terminal device specifications.