The present document specifies test methods to allow the minimum performance requirements for the electro-acoustic characteristics of GSM, 3G, LTE, NR and WLAN terminals when used to provide narrowband, wideband, super-wideband or fullband telephony to be assessed. The objective for narrowband services is to reach a quality as close as possible to ITU-T standards for PSTN circuits. However, due to technical and economic factors, there cannot be full compliance with the general characteristics of international telephone connections and circuits recommended by the ITU-T. The performance requirements are specified in TS 26.131; the test methods and considerations are specified in the main body of the text.

The present document is applicable to any terminal capable of supporting narrowband, wideband, super-wideband or fullband telephony, either as a stand-alone service or as the telephony component of a multimedia service. The present document specifies test methods to allow the minimum performance requirements for the electro-acoustic characteristics of GSM, 3G, LTE, NR and WLAN terminals when used to provide narrowband, wideband, super-wideband or fullband telephony to be assessed.