Forcing SG-SMS on EG915U

Hi Quectel Forums,

We have a device using an EG915U-EU module on an m2m network with IMS VoLTE support, but not SMS over IP. As a result, the module often tries to send on SMS over IP for long period, rendering it unusable while waiting for the CMGS reply from the module, until it falls back to SG-SMS. These waits stall the AT port for 1-3 minutes at a time.
I see in other AT references that there was at command to change sms domain pref:

AT+QNVFW=“/nv/item_files/modem/mmode/sms_domain_pref”,00

But this doesn’t appear to be present on the EG915U modules, and I could not find an equivalent command in the EG9x reference.
The device needs both voice (VoLTE) and SMS. Does someone know of a way to force SG-SMS on the EG9x series?

Hi @cameron-apt
Do you want to send SMS over SGs? If so, please try AT+QIMS=“DISABLE” command.

Hi Hayes, thanks for the response, I will give it a shot, but we still need VoLTE support which I believe AT+QIMS=“DISABLE” will break. I will try this out though to confirm, thanks.

Hi Hayes, unfortunately, while AT+QIMS=“DISABLE” does cause SMS to work correctly, it also disables VoLTE. We are hoping to get the EG915U to send SMS over SG while still supporting VoLTE, since our m2m provider doesn’t yet support SMS over IP.

This can only be achieved if the operator does not support IMS, as VOLTE must use IMS. So these two functions cannot be implemented simultaneously.