nRF9160 LTE-M, SMS problems

[Babarskas]

Hello, I am not able to send sms, and probably connect to LTE-m. I am using at_client example, modem version mfw_nrf9160_1.3.0, nRF connect SDK v1.5.1, v1.6 tried on both.  

For sending message I am using this example https://devzone.nordicsemi.com/f/nordic-q-a/41755/sending-sms-using-at_client-example. 

> AT%XSYSTEMMODE=1,1,0,0
OK
> AT+CFUN=1
OK
> AT+CFUN?
OK
> AT+CNUM
+CME ERROR: 0
AT+CEREG?
+CEREG: 0,1,"19C8","09C4D267",9
OK

In this example for me CNUM always is error even though LTE link monitor shows all greens.

I live in Lithuania tried changing sim cards but can't get this working. Also if I use AT+CMGS I always get error 301. 

[Heidi]

Hi!

You're getting +CME error 0 (phone failure) from +CNUM and +CSM error 301 (SMS service of ME reserved) from +CMGS. 

I see you're connected to an NB-IoT cell.

Have you tried %XSYSTEMMODE=1,1,0,1, i.e specifying that LTE-M is your preferred connection protocol?

If you are able to take a modem trace that would help us get to the root of the issue.

Best regards,

Heidi

[Babarskas]

Sorry for late response but i am currently on vacation. However i tried your suggestion but result is still the same so I am sending Trace Collector .bin file to you. Am i correct to asume that i can't use this file for my own debuging because when i open it, text is unreadable.trace-2021-07-15T06-27-05.617Z.bin 

[Babarskas]

Hello, no I didn't try to take a new log because I can't connect to LTE-M network. nRF9160 searches network for a while and then grays out and that is it. Do you have any tips how to connect to LTE-M? And why can't I get my phone number when I use CNUM command I always get failed: phone failure. 

[Heidi]

Hi, I will need more information to know why the device isn't able to connect to LTE-M. 

Please take a modem trace using the Trace Collector application in nRF Connect for Desktop while the device is trying to connect to a network and I will be able to see why it isn't able to. Make sure to enable the config CONFIG_NRF_MODEM_LIB_TRACE_ENABLED in your application before taking the trace.

[Babarskas]

trace-2021-08-19T12-35-24.478Z.bin

Hope you will find something.

[Babarskas]

trace-2021-08-20T11-45-07.061Z.binI made trace collector with asset tracker example also maybe this will give you more information.

[Heidi]

Hi! Both traces are empty. Make sure that the size of the trace increases in the Trace Collector app as you are running the application. Additionally, if you are running a custom application, make sure UART1 isn't being used by something else.