can make it difficult to distinguish the DTMF tones, or can also lead to duplicate tones being detected (if a noise chops a single DTMF sound into two parts). This could be because of the settings in the handset, manufacturing defect, speaker/earphone mode, etc.Ĭarrier Issues: One or more carriers involved during the transmission of DTMF tones fail to transmit it properly (This could be due to a combination of the handset, operators, location/cell towers involved).Įnvironmental Factors: Any factor which can cause sound (DTMF tone) to be altered or lost, such as background noise, poor reception, poor audio quality, etc. Handset Issues: The handset is not sending the DTMF tones correctly over the telephony lines. Possible reasons why DTMF is not captured correctly: In the rarest of rare cases, the alphabet (A, B, C, D) can also appear instead of digits as they are part of the DTMF tones. For example, the user presses ‘12345’, but the digits captured appear like ‘22345’.

For example - The user presses ‘12345’, but the digits captured are like ‘1345’ĭigits are recognized wrongly. For example - The user presses ‘12345’, but the digits captured are ‘123455’Ī few digits are missing. For example - The user presses 1, but no digits are captured.ĭuplicate digits appear in a few cases. Scenarios: What can go wrong in DTMF capture-ĭigits are not captured at all even after key presses from the users of a specific handset. Such tones are passed from the handset across one or more intermediate operator lines before it finally reaches Exotel.ĭTMF can be sent across phone networks in multiple ways, one is “In-Band Signalling”, where the DTMF tones are played in the audio channel of the call whereas in the case of “Out-of-Band Signalling”, the tones are sent in a separate signalling channel. Modified on: Sun, 5 Mar, 2023 at 10:12 PMĭTMF ( Dual-tone multi-frequency signalling) uses voice frequency which is transmitted over telephone lines for capturing digits upon key press. Solution home Voice & Phone Calls Call Docs Troubleshooting with DTMF (Gather / IVR)

Dtmf sound