ITU-T G.109

This Recommendation defines five categories of end-to-end speech transmission quality for 3.1 kHz handset telephony. These categories are defined as ranges of speech transmission quality in terms of user satisfaction, tied to the ratings given by the transmission planning tool of Recommendation G.107 which takes into account the combined effects of various transmission impairments. The definitions provided here are independent of any specific technology that may be used in different types of network scenarios under consideration.