TIA ANSI/TIA-470.230-D

This standard establishes criteria and procedures for evaluating the DTMF, Pulse Dial, and Flash network signaling performance of analog telephones and terminals. Such equipment may be connected to the Public Switched Telephone Network (PSTN) to provide traditional narrowband (300 to 3300 Hz) wireline telephone service. It may also be connected to Analog Terminal Adapters (ATAs) and Voice Gateways (VGs) that provide packet-based services such as Voice over Internet Protocol (VoIP), some of which are capable of supporting wideband (100 to 7000 Hz) voice transmission.

These requirements should ensure compatibility and satisfactory performance to the user in a high percentage of installations.