EP06-E (EP06ELAR04A22M4G): VoLTE call fails on Free Mobile (France) – need French MBN / IMS registration check

IoT Modules LTE-A Module
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Hello,

I’m using an EP06-E, firmware EP06ELAR04A22M4G (release notes V0422), connected over USB to Windows 11, with a Free Mobile SIM (MCC/MNC 208/15). Outgoing voice calls fail immediately and I would like to know which MBN to use for France, and how to check IMS registration on this module.

Network state (all OK)

  • AT+COPS? → +COPS: 0,0,"Free Free",7
  • AT+CEREG? → +CEREG: 0,1, AT+CSQ → +CSQ: 31,99
  • AT+QENG="servingcell" → LTE FDD, 208/15, EARFCN 3350, RSRP -82, state NOCONN

IMS / MBN

  • AT+QCFG="ims" → +QCFG: "ims",1,1
  • AT+QMBNCFG="AutoSel" → 1. Active MBN: ROW_Generic_3GPP (0x06010821, 202307171). The list contains only Telstra-Commercial_VoLTE, Volte_OpenMkt-Commercial-CMCC, OpenMkt-Commercial-CU, TW_Mobile-Commercial_VoLTE, Commercial-DT-VOLTE, Commercial-KT, Commercial-Reliance. No French operator MBN.
  • AT+CGDCONT? → cid1 IPV4V6 “free”, cid2 IPV4V6 “ims”, cid3 IPV4V6 “sos”, cid4 IP “free”
  • AT+CGACT? → cid1 and cid2 active (1,1, 2,1), cid3 and cid4 inactive. AT+CGPADDR → cid2 has an IPv6 address.

Call test

  • AT+QPCMV=1,2 → OK (this command is not in the EP06 AT manual)
  • ATD<number>; (national and +33 format) → NO CARRIER after ~65 ms
  • AT+CLCC → only 2 PS entries (+CLCC: 1,1,0,1,0,"",128 and 2,1,0,1,0,"",128), no voice call
  • AT+CEER → +CEER: 5,36 (PS LTE cause 36, “regular deactivation”, according to the LTE Standard error code list). Before, it returned +CEER: 0,-1.
  • AT+COLP? → +COLP: 0,2

Context
Free Mobile has shut down its own 3G, and normal voice calls require VoLTE (only emergency calls fall back to Orange 3G), so there is no CS fallback. The call seems to fail locally, before any signalling, which makes me think IMS is not registered.

Questions

  1. Is there an official MBN (or IMS profile) for France (Free, Orange, SFR, Bouygues) for the EP06-E and firmware R04A22M4G? If so, could you provide it (for example “Bouygues_France_VoLTE”, which I saw listed on EC25-EUX)?
  2. Is ROW_Generic_3GPP expected to register on IMS with French operators, or is an operator MBN required?
  3. How can I check the IMS/SIP registration status on EP06 (AT+CIREG? returns ERROR)?
  4. Is voice over USB (AT+QPCMV=1,2, UAC) officially supported on EP06-E R04A22M4G? The EVB user guide lists “voice over USB*” as under development.
  5. Which logs do you need (QLog, IMS/SIP)? I can provide them.

Thanks in advance.

2

Hi @BugDroid

Please find our feedback below:

  1. The R04A22M4G firmware (latest version) does not support MBN or IMS profiles for France. Therefore, the requested France operator profiles are not available for this firmware version.
  2. The ROW_Generic_3GPP MBN contains baseline 3GPP non-volatile parameter settings. When automatic MBN selection is enabled using AT+QMBNCFG=“AutoSel”,1, and no matching carrier MBN is found for the SIM card’s IMSI, the module will automatically use ROW_Generic_3GPP.
  3. AT+CIREG? is not supported on EP06 modules and will return ERROR. For EP06 series modules, the IMS registration status can be queried using AT+QCFG=“ims”.
  4. Currently, UAC is not supported on the EP06-E firmware.