Revision Standard – Superseded.Practical methods for making laboratory measurements of electroacoustic characteristics of analog and digital telephones, handsets, and headsets are provided in this revised standard. The methods may also be applicable to a wide variety of other communications equipment, including cordless, wireless, and mobile communications devices. Measurement results may be used to evaluate these devices on a standardized basis. Application is in the frequency range 100¿¿¿8500 Hz.