This standard provides the techniques for objective measurement of electroacoustic characteristics of analog and digital telephones, handsets and headsets. Application is in the frequency range from 100 Hz to 8500 Hz. Although not specifically within the scope of this standard, the methods described are generally applicable to a wide variety of other communications equipment, including cordless, wireless and mobile communications devices. Digital devices that have audio characteristics of a digital telephone can be tested as a digital telephone, even if they do not have a dialpad or other similar telephone functions. USB headsets are one example of devices in this class. Telephones with speakerphone features are covered by IEEE Std 1329(TM). Due to the various characteristics of these devices and the environments in which they operate, not all of the test procedures in this standard are applicable to all types of telephones, handsets or headsets. Application of the test procedures to atypical telephones should be determined on an individual basis.