Recommendation ITU-T P.1100 describes performance requirements and test methods for narrow-band hands free communication in vehicles. This Recommendation covers: - build-in hands-free systems; - after-market hands-free car kits; - corded headsets; and - wireless headsets; to be used in vehicles for communication while driving. This Recommendation addresses the test of complete systems as well as the subsystems of hands free microphone and telephone with short-range wireless transmission link used to interconnect the hands-free system to the mobile network. For testing, the test set-up and the recommended environmental conditions are described. The methods, the analysis and the performance parameters described in this Recommendation are based on test signals and test procedures as defined in Recommendations ITU-T, ITU-T P.501, ITU-T P.502, ITU-T P.340 and ITU-T P.380.