Connected to LTE with Twilio SuperSIM

[JWizard]

Hello,

I can connect to LTE with the iBasis SIM that came with the nRF9160DK but have been unable to connect with any other SIM.

Here is what happens in the LTE Link Monitor when I reset the DK with a Twilio SuperSIM inserted:


I checked the APN afterwards to see if it was getting that but it looks like it is not. The APN has been given to me as just "super."

How can I troubleshoot this inability to connect to LTE?

[Didrik Rokhaug]

Hi.

First, are you certain that the SIM card/your subscription supports LTE-M?

Which modem firmware version are you using?

A new one, v1.1.1, was released recently. If you are using an older one, could you try to upgrade, and see if that solves your problem?

If not, I will need a modem trace to identify your problem. You can follow this guide to learn how to take a modem trace: https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/how-to-get-modem-trace-using-trace-collector-in-nrf-connect

Best regards,

Didrik

[JWizard]

Hi Didrik,

1) Twilio is assuring me that my card supports LTE-M

2) I updated my Modem Frimware to v1.1.1 but saw no change

3) I setup the asset Tracker App to take a modem trace. It just kept growing so I stopped it at 500 kB. My thought was that it was probably recording the same kind of thing over and over again. I will attach the trace here.

Please let me know steps to produce a different set of trace data if required.

Thank you very much for the support.

trace-2020-02-13T17-31-56.020Z.bin

[Didrik Rokhaug]

It looks like the modem is able to find some networks, but is not allowed to connect.

I'll double-check with the modem team to be sure.

Does Twilio have roaming agreements with your local operators?

[JWizard]

Didrik Rokhaug said:

Does Twilio have roaming agreements with your local operators?

The operator Twilio has agreements with is T-Mobile. We have T-Mobile coverage and use Twilio cards in other devices. I'm unsure of the significance of "roaming" here. I am under the impression that we are not roaming as we are in a metropolitan area with coverage provided by T-Mobile.

That being said. I believe the direct answer to your question is: no, Twilio does not have roaming agreements with local operators.

[Didrik Rokhaug]

"Roaming" simply means that you are connected to the network of a different network provider than "your own", i.e. Twilio.

Some network providers, such as iBasis, do not have their own base stations and are therefore always roaming.

The modem team agrees with my analysis. The nRF91 finds the correct network (AT&T), but the tracking area is not allowed.

Should you have service in your area?

If so, you should check with Twilio.

[JWizard]

Oh man. They told us that they sent us already activated cards. We just went through the activation steps and now it appears to work.

LED 4 remains lit.

AT+CGDCONT? returns the expected APN and an IP address.

If I look in nRFCloud I get an "Asset Orientation" report each time I flip Switch 1.

I think this is resolved. Thank you for your time in looking into this matter. I should have verified the SIM card sooner.