Recommendation ITU-T J.1201 specifies the functional requirements of a smart TV operating system. The smart TV operating system is intended to be installed in IBB capable cable STB and TV and to enable broadcasting and IP-based interactive services provided by cable television operators and third-party providers. By running the smart TV operating system, the IBB capable cable STB and TV will be able to intelligently provide subscribers with advanced and personalized services by downloading and installing advanced and personalized Apps from cable operators' platforms and third-party platforms, which are interconnected with the related cable operators' platforms. This Recommendation is the first Recommendation of a smart TV operating system series. The Recommendations for this smart TV operating system will cover functional requirements, architecture, security and APIs