EC25-J Mini PCIe + Rakuten Mobile SIM: ATD Voice Call (CS/VoLTE) Support and Recommended Firmware?

Dear Alvin,

Sorry for the very late reply, and thank you for your answer.

We enabled IMS using:

AT+QCFG=“ims”,1,1

After further testing, we have made progress. With EC25-J Mini PCIe and a Rakuten Mobile SIM, VoLTE voice calling by ATD is now working in our environment, and the remote party can hear the prompt audio.

I would still like to request the latest firmware you mentioned:

EC25JFAR06A06M4G_01.009.01.009

Our module part numbers are:

  • EC25JFA-512-KJC
  • EC25JFA-512-DJC
  • EC25JFA-512-SJC

The remaining issue is incoming DTMF during VoLTE calls. I opened a separate topic for the DTMF details here:

In short:

  • VoLTE call audio is working
  • AT+QTONEDET is enabled
  • The remote party presses one keypad digit during the prompt
  • The host side does not observe +QTONEDET URC
  • Asterisk / chan_quectel also does not receive any DTMF event

We can provide sanitized AT command flow and diagnostic summaries privately if needed. We cannot share IMEI/IMSI/SIM identifiers, phone numbers, credentials, or raw QLog/SIP/IMS captures publicly.

Thank you.