Request to enable IMS-SMS support in Commercial-LGU MBN profile

IoT Modules GSM Module
1

Hello,

I am currently using the Commercial-LGU MBN profile on a Quectel EC25/EG25 module.
SMS sending over the LGU+ LTE network fails with +CMS ERROR: 350 or “NO CARRIER” unless the network supports CS fallback. As you know, LGU+ operates LTE-only without CS domain, so SMS must be sent over IMS (SMS over IMS).

However, it seems that the current Commercial-LGU MBN does not enable IMS-SMS, and there is no smsdomain configuration available in AT+QIMSCFG. This prevents forcing SMS to be sent over IMS or allowing PS fallback for SMS.

Could you please provide a patched Commercial-LGU MBN or updated firmware that:

  1. Enables SMS over IMS (IMS-SMS) in the Commercial-LGU profile, and/or
  2. Allows AT+QIMSCFG="smsdomain" access, or enables PS fallback for SMS in LTE-only environments.

This feature is critical for sending SMS on LGU+ and LGU+ MVNO networks where CS domain is unavailable.

Thank you for your support.

2

Please provide your current detailed version.

AT+QGMR

3

the firmware version is
[EC25EFAR08A05M4G_KR_01.001.01.001]

4

this is the latest one

5

I purchased the EC25-EAF and am using it with the KR firmware version EC25EFAR08A05M4G_KR_01.001.01.001 and an LGU+ SIM card.
When selecting the LGU+ MBN, the module freezes and becomes unresponsive when sending SMS.

Additionally, when switching to the 3GPP MBN, the SMS issue is resolved, but:
• The call quality appears to be degraded, and
• About 4 out of 10 outgoing calls result in the message, “We’re sorry, the recipient’s device cannot be connected,” and the call fails.

I would like to inquire about the following:

  1. How to achieve perfectly clear and stable call quality for both parties.
  2. The model name of a module that can operate with the LGU+ MBN and have both VoLTE calls and SMS working properly.

Thank you for your confirmation and reply.