This ITU-T Recommendation describes methods and procedures for conducting subjective performance evaluations of hands-free terminals. The use of hands-free terminals in communication has numerous advantages for the telephone users, especially for all non-traditional types of terminals such as car phones, computer/laptop-type terminals and others. Due to the complex acoustical situation a big variety of signal processing which may be non-linear and/or time variant is expected. ITU-T Recommendation P.340 describes measurement techniques for hands-free terminals, ITU-T Recommendation P.581 describes the use of the HATS for the evaluation of terminals, ITU-T Recommendations P.501 and P.502 describe measurement signals and analysis procedures. Using these methods a minimum performance of hands-free terminals should be ensured. However, there is always the possibility that those tests do not address fully the impact of all kinds of signal processing in a hands-free terminal and their impact on speech transmission quality. Subjective testing is a commonly used method of assessing the performance of terminals, including digital speech codecs, voice-operated signal processing, echo cancellation, noise reduction and other types of signal processing. This ITU-T Recommendation defines methods for the subjective evaluation all kinds of hands-free terminals.