This Recommendation provides 3.1 kHz telephony speech transmission performance requirements for the whole range of packet-based gateways and terminals, including wireless and softphones. Measurement methodologies are not covered by this Recommendation, however, work on this topic is under way in Study Group 12 and is planned to be incorporated in a future revision or, alternatively, in a separate new Recommendation. Also, requirements for wideband telephony may be added in a future version of this Recommendation.