This Recommendation deals with electro-acoustic performance parameters of portable digital cordless and mobile terminals. The requirements given below should ensure satisfactory voice service in a high percentage of installations under normal conditions@ but other factors impacting the performance@ such as the radio link@ are not included. This Recommendation could be used as the baseline text of requirements and test methods for mobile or cordless telephony@ e.g.@ when developing new telephony systems. It is not intended to override other acoustic specifications that have been developed for specific telephony systems. This Recommendation includes specifications for handsets@ headsets and speakerphone sets of mobile terminals. These specifications may be applicable to digital cordless handsets@ headsets and speakerphone sets. The requirements contained in this Recommendation apply only to narrowband systems (3.1 kHz) and wideband systems (7 kHz) regardless of the coding algorithm used. Specifications for speakerphone sets are recommended for handheld terminals and desktops. Specifications for car mounted hands-free terminals will be included in a separate Recommendation. Requirements are given for handsets@ headsets and speakerphone sets in conjunction with a 0 dBr 4-wire reference (see Figure 1) base station having an appropriate air interface@ and are specified irrespective of the particular technology and air interface.