This revised version of Recommendation ITU-T P.581 covers hands-free (including speakerphone, loudspeaking and headset) and handset terminals and includes clauses for the calibration and use of the head and torso simulator (HATS) for handset and headset terminals. This Recommendation specifies the use of the HATS for speakerphone terminal subjective and objective evaluations (e.g., Recommendation ITU T P.340). It defines the test arrangements, the mouth calibration, the binaural equalization and loudness summation, as well as the method for headphone calibration to be applied for subjective third-party listening tests as described in Recommendation ITU-T P.832.