The complexity of signal processing in modern communications requires advanced test procedures. This goes both for telecommunication networks and for terminal equipment. Hands-free telephones (HFT) are a typical example of telecommunication equipment showing a nonlinear, time-variant, and speech-controlled transmission characteristic. In addition, the performance depends heavily on the environmental conditions like test rooms or ambient noise. New test procedures, both auditory and instrumental, have been developed during the last few years to determine quality aspects of HFT’s. The principles of auditory tests as conversational tests, specific double-talk tests, and a new realization of listening-only tests are discussed. These procedures are used for both parameter identification and value selection. The parameters found to be auditory relevant have been identified, and advanced tests for quality parameters—determining the auditory quality—were developed.