Hello Quectel team,
I would like to confirm the expected EC25 behavior for incoming DTMF during a VoLTE / IMS voice call.
Environment:
- Module family: EC25
- Voice call: VoLTE / IMS
- AT+QTONEDET is enabled
- Downlink audio from the module to the remote phone is audible
- The remote party presses one valid keypad digit during the prompt using a standard smartphone phone app
- Host side does not observe +QTONEDET URC
- Asterisk / chan_quectel also does not receive any DTMF event
- RX PCM / DSP frame counters advance, but no DTMF candidate or accepted event is observed
- AT+QAUDCFG=“voltedtmfcfg” write is accepted, but readback only returns OK, so the effective value cannot be confirmed from AT response
Questions:
- Does EC25 generate +QTONEDET URC for incoming DTMF during VoLTE / IMS calls?
- If the network uses RFC2833/RFC4733 telephone-event for IMS DTMF, does EC25 convert it into +QTONEDET URC?
- Does EC25 convert IMS telephone-event into an in-band PCM DTMF tone on the audio path?
- Are there required AT settings, firmware conditions, MBN conditions, or URC output port requirements for incoming VoLTE DTMF detection?
- Is AT+QAUDCFG=“voltedtmfcfg” relevant for incoming VoLTE DTMF detection, or only for DTMF sending / another path?
- Which QLog/QXDM events or decoder package should be used to confirm whether telephone-event reaches the module?
- Are there known EC25 firmware/MBN limitations for incoming VoLTE DTMF / QTONEDET?
I can provide sanitized diagnostic summaries privately if needed, but I cannot share IMEI/IMSI/SIM identifiers, phone numbers, credentials, or raw QLog/SIP/IMS captures publicly.
Thank you.