Voice Over USB + VoLTE + RM502Q-GL

Dear all,

i’ve followed the Quectel_EC2x_EG9x_Voice_Over_USB_and_UAC_Application_Not_V1.0.pdf to enable UAC on my RM502Q-GL (fw version: RM502QGLAAR11A02M4G).

Using AirScreen tool, on the DIAG port I can see that VoLTE is successfully registered, but if i’m trying an inbound call I got:

  • SIP Invite
  • SIP 100 - Trying
  • SIP 486 - Busy Here

So looks like that the module itself doens’t permit to answer the call. I’ve also tried to put it in WCDMA mode, and still no way to get a call. Trying an outgoing call with ATD command give me “NO CARRIER” error (both LTE/CS mode).

Interesting part is that and incoming call (both LTE/CS mode) doesn’t generate “RING” urc on AT port.

May i’m missing something special, or is a problem of the firmware that i’m running?

Thanks in advance

Dear @stich86
Please query firmware via AT+QGMR.