scope:

This standard establishes voice performance requirements for wideband digital, wireline telephones where transmission is in digital format. A telephone is defined as a device that terminates networks and provides telephony voice service. Transmission may be over Local Area Networks, Firewire/IEEE-1394, Universal Serial Bus (USB), public ISDN or digital over twisted pair wire. Applications include Voice over Internet Protocol (VoIP), and PCM-based telephones, whether connected through modems, gateways, or PBXs and personal computer-based telephones, which may or may not have handsets.

Technical requirements are set for handset, headset and handsfree (speakerphone) modes of operation. These requirements apply regardless of the technology used to couple the handset or headset to the telephone. Coupling may be by a cord, a short-range air-interface such as, but not limited to, a radio interface, an electric field interface, a magnetic field interface or an infra-red interface.