Asterisk VoLTE support

I am using EC20CEFAG on Raspberry Pi 4B with kernel system of arm64.
The card is recognized under the system.
I didn’t compile the drivers for it.
Right now my issue is Voice support.
It shows “Dongle has NO voice support”
How can I turn it on?

My step


+QPCMV: (0,1),(0-2)




+QPCMV: (0,1),(0-2)



First, I want to enable voice on USB, make /dev/ttyUSB1 can used be voice, then I would like to use VoLTE as voice function, not CS.
By the way, sms service center is empty,
I sent this, it is empty the same.
So, I can not make calls and send sms.
Pls help!
Reply in Chinese that is appreciate.

/dev/ttyUSB0 is a diagnostic port
/dev/ttyUSB1 is the GPS/USB Audio Data port
/dev/ttyUSB2 is the control port that you want to send the AT command to
/dev/ttyUSB3 is a duplicate control port, can’t remember why it exists but it’s basically the same as USB2
/dev/cdc-wdm0 is your data port for QMI mode
/dev/ttyATH0 is the internal serial port of the MiFi itself, nothing to do with the modem.

So to test you need to do a few things:

  1. send command AT+QGPSCFG=“outport”,“none” to /dev/ttyUSB2 to make sure GPS output is disabled. Voice over USB uses the same port as GPS, so you need to make sure GPS output is off.
  2. send command “AT+QPCMV=1,0” on /dev/ttyUSB2
  3. Verify with command “AT+QPCMV?” on /dev/ttyUSB2. If it works, you should get “+QPCMV:0,0”

If that all goes well, then time for a test call
4) Open a terminal program to monitor /dev/ttyUSB1 (this is where the audio should be sent)
5) Use command “ATDYYYYYYYYYY;” where YYYYYYYYYY is a phone number you want to try calling out to. Command should return OK straight away. Call should go through once dialing completes though
6) Answer call, and say something on phone you dialed. You should immeidately see traffic appearing in the terminal monitoring /dev/ttyUSB1

the above is copied from other website.
Is that available?

crw-rw---- 1 root dialout 204, 64 Jul 24 15:25 /dev/ttyAMA0
crw-rw-rw- 1 root dialout 188, 0 Jul 24 15:25 /dev/ttyUSB0
crw-rw-rw- 1 root dialout 188, 1 Jul 24 15:25 /dev/ttyUSB1
crw-rw-rw- 1 root dialout 188, 2 Jul 24 15:30 /dev/ttyUSB2
crw-rw-rw- 1 root dialout 188, 3 Jul 24 15:33 /dev/ttyUSB3
crw-rw-rw- 1 root dialout 188, 4 Jul 24 15:32 /dev/ttyUSB4

and after some commands, USB devices change from 0-3 to 0-4, is that means ttyUSB4 is Voice?

Audio : /dev/ttyUSB1
Data : /dev/ttyUSB3

-------------- Status -------------
Device : dongle0
State : Free
Audio : /dev/ttyUSB1
Data : /dev/ttyUSB3
Voice : No
SMS : Yes
Manufacturer : Quectel
Model : EC20F
Firmware : EC20CEFAGR06A15M4G
IMEI : 869xxxxxx
IMSI : 460xxxxxx
GSM Registration Status : Registered, home network
RSSI : 20, -73 dBm
Mode : No Service
Submode : No service
Provider Name : CHN-UNICOM
Location area code : “231C”
Cell ID : "A5CB60
Subscriber Number : +86186xxxxx
SMS Service Center :
Use UCS-2 encoding : Yes
USSD use 7 bit encoding : No
USSD use UCS-2 decoding : Yes
Tasks in queue : 0
Commands in queue : 0
Call Waiting : Disabled
Current device state : start
Desired device state : start
When change state : now
Calls/Channels : 0
Active : 0
Held : 0
Dialing : 0
Alerting : 0
Incoming : 0
Waiting : 0
Releasing : 0
Initializing : 0


Do you have Teamviewer? We can have a remote session.

Best Regards,


Hello copperfiled, Willie,

If this was resolved please could the solution be summarised and published here.

If possible I wish to achieve the following:

Summary: Analog phone FXS calls over VoLTE with Quectel EC25, EP06 and >Cat6 modems

Equipment Bill of Materials

Is this feasible and likely to be successful?

I look forward to hearing from you.

Many thanks,

i glad i found this topic. the quote as answer above “from another forum” is was for me, its from gl-inet forum.
i still trying to resolve my problem too. today i finally get in idea my EC25-AF modemd’s firmware is possible too old and need’s upgrade first. anyone here can help with this? so i can continue with driver after modem can get voice working first.

this forum is simply dead? or just very low activity here… i did’n expecting that :face_with_raised_eyebrow:

Hi, pl4sm0nk,

you need to upgrade the firmware of EC25-AF, right?

Could you create a new post for me to tracking on your question?

And have you ever tried downloading the firmware from our home website?

if you can not get the firmware, you could let me know , I will try to send you the latest version firmware.

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thanks @Job.Bao-Q!

Anyway, i compiled fresh driver, everyone please test it!
i did applied the patches of ca4ti and others but surely its not done yet (needs your feedback)

the limitation is for limiting some unrelated people and some person who want to post some unrelated info.

any solution?
volte support

Code for Quectel modules with Asterisk here

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