Recommendation ITU-T P.56 describes an easy to implement method to objectively determine the active speech level. It also acts as a reference against which other methods can be compared. The purpose of this Recommendation is not to exclude any other method but to ensure that results from different methods give the same result.
In the early 2011 revision Annex B was added providing the necessary information on how to use the active speech level meter for super-wideband (SWB) signals.
This second 2011 revision adds Annex C, which provides the necessary information on how to use the active speech level meter for full band (FB) signals.