DTMF Issues

Diagnose and resolve problems with DTMF tone detection during calls.

If your auto attendant intermittently fails when callers press menu selections, the issue is likely caused by DTMF (Dual-Tone Multi-Frequency) problems. Ensure your system supports RFC2833 rather than older inband DTMF.

  • Inband: Digits are transmitted as audio tones without special coding or markers. On VoIP and SIP networks, inband DTMF is unreliable and is often the cause of menu failures.

  • RFC2833: The preferred standard for signalling DTMF tones, fax-related tones, and country-specific subscriber line tones.