Send/Receive SMS asset tracker v2

[danimalia]

Hi there

We managed to send/receive SMS on the nRF91Dk using the asset_tracker_v1 example, which contains the at_client. 

However, with the asset_tracker_v2 we never get the at command indicating SMS message received. (+CMT). 

Setup that worked with asset tracker v1: 

AT+CNUM

AT+CNMI=3.2.0.1

Sending an SMS to the number provided by CNUM: 

Is there any additional setup required for asset_tracker_v2? 

Same sim card, same dev kit. 

Kind regards

Dan

[Markus Tacker (he/him)]

However, this is caused by the AT host library being disabled by default in asset_tracker_v2, so it won't process AT commands sent to it. It can be enabled like this:

CONFIG_UART_INTERRUPT_DRIVEN=y
CONFIG_AT_HOST_LIBRARY=y

Depending on the content of the SMS AT command you send and the configuration of the line termination characters on the PC side, you may also need to set CONFIG_CR_LF_TERMINATION=y or CONFIG_LF_TERMINATION=y (By default CR termination is used to work with most PC applications, but this may cause issues with SMS commands, as CR also is used as a control character within the command when adding a payload to it).

[danimalia]

Sorry for the delayed response. Enabling the uart interrupt didn't make a difference, but changing the project settings as below did. 

We now receive the sms's but not consistently. The sms seems to always come through if sent during an active connection, but only intermittently on reconnect if sent during either gps fix or idle. If we reset the modem the sms's sent during these times also comes through. 

Any ideas?

[danimalia]

I also want to ask if we should check the eDRX settings as in this thread: 

https://devzone.nordicsemi.com/f/nordic-q-a/49379/how-to-receive-sms-message-in-standby-mode-in-nrf9160

However we're running a custom version of asset_tracker_v2 with ncs 1.5.1; I'm not sure how to set eDRX setting with no AT commands. 

[Markus Tacker (he/him)]

Hei,

you can use the Link Controller to enable eDRX: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.5.1/nrf/include/modem/lte_lc.html#c.lte_lc_edrx_req

~Markus

[danimalia]

just to close out this loop for anyone searching for the answer. eDRX must be enabled in the prj.conf file (CONFIG_LTE_EDRX_REQ=y). the default eDRX interval is 163.84 seconds which if you're unaware of, can look like you're not receiving an sms for almost 3 minutes. this can be changed iby adjusting the definition of edrx_param. 

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fref_at_commands%2FREF%2Fat_commands%2Fnw_service%2Fcedrxrdp.html