Modem UTC Time Not Correct When Connected To Verzion Network

[JLCIOT]

We have an issue with the UTC Time being the correct time when we initially connect to the Verizon network.  However, after some period of time the UTC Time changes and our time for logging events is not correct.  This only happens when the nr9160 is connected to the Verizon Network.

See debug information below for correct and incorrect UTC Time.  The 0 UTC Time Is Not Correct for our time zone which is EST!!

Modem date-time: 25/04/03,13:49:08+00
RTC date-time: 04/03/2025 09:49:06 (-4 UTC)
uptime date-time: 04/03/2025 09:49:06 (-4 UTC) 1743673746

Modem date-time: 25/04/03,13:45:11+00
RTC date-time: 04/03/2025 13:45:10 (0 UTC)
uptime date-time: 04/03/2025 13:45:10 (0 UTC) 1743687910

[dejans]

Hi,

Can you provide information about your application? Is it based on any of our samples?

Which SIM card do you use?

How many devices do you have and how many are affected by this issue?

after some period of time the UTC Time changes and our time for logging events is not correct. 

Is this incorrect reporting of time random? How often does this happen? After this issue happens, when do you start getting correct values again?

Best regards,
Dejan

[JLCIOT]

Our application uses the nrf9160 asset tracker example from the DK board.  We have used this code for several years with various SDK versions.  We recently updated our software application code to SDK Version 2.9.

We are using the Hologram Global SIM card which supports the major cellular networks in the US (i.e. Verizon, T-Mobile, AT&T).  

We have tested approximately 10 of our units that are affected by this issue.  When we initially connect to the Verizon Network, the UTC time is usually correct.  After a random period of time, the UTC time is not correct.

This issue is repeatable on all 10 of the sensors that were tested.   When this issue occurs, the only way for us to correct the issue is to perform a software or hard reset our board.

Note that we also have SIM cards from Verizon.  This also happens when using the Verizon supplied SIM cards.

[JLCIOT]

I need to make an update to the information in this ticket.

It is not the UTC time provided by the modem that is incorrect.  It is the RTC time zone settings that are associated with the modem UTC time that is not correct.  On initial power on after we connect to the Verizon Network, both the modem UTC time and RTC time zone (-4 UTC) are correct.  After some random period of time, the modem UTC time is correct but the RTC time zone changes to (0 UTC).  Note we are in the EST time zone.

Our question is why is the RTC time zone changing?

[dejans]

Hi,

JLCIOT said:

We recently updated our software application code to SDK Version 2.9.

From which NCS version did you update to v2.9.0?
Was there the same problem with your previously used NCS version?

Which modem firmware version do you use?

Best regards,
Dejan

[JLCIOT]

We updated from SDK Version 1.7.0 to SDK Version 2.9.

The same problem existed with SDK Version 1.7.0.

We are using modem firmware Version 1.3.5.