RES655 – 372 – ADD RESOLUTION 655 (WRC-15) Definition of time scale and dissemination of time signals via radiocommunication systems The World Radiocommunication Conference (Geneva, 2015), considering a) that the ITU Radiocommunication Sector (ITU-R) is responsible for defining the standard frequency and time signal service and the standard frequency and time signal-satellite service for the dissemination of time signals via radiocommunication; b) that the International Bureau of Weights and Measures (BIPM) is responsible for establishing and maintaining the second of the International System of Units (SI) and its dissemination through the reference time scale; c) that the definition of reference time scale and dissemination of time signals via radiocommunication systems are important for applications and equipment that require a time traceable to the reference time, considering further a) that ITU-R is an organization member of the Consultative Committee for Time and Frequency (CCTF) and participates in the General Conference on Weights and Measures (CGPM) as an observer; b) that BIPM is a Sector Member of ITU-R and participates in the relevant activities of ITU-R, noting a) that the international reference time scale is the legal basis for time-keeping for many countries, and de facto is the time scale used in the majority of countries; b) that disseminated time signals are used not only in telecommunications but also in many industries and practically all areas of human activities; c) that time signals are disseminated by both wired communications covered by Recommendations of the ITU Telecommunication Standardization Sector (ITU-T) and by systems of different radiocommunication services (space and terrestrial), including the standard frequency and time signal service for which ITU-R is responsible, recognizing a) that No. 26.1 states that: “Attention should be given to the extension of this service to those areas of the world not adequately served”; b) that No. 26.6 states that: “In selecting the technical characteristics of standard frequency and time signal transmissions, administrations shall be guided by the relevant ITU-R Recommendations”;