ublox SARA does not connect

[ron]

Hi

Since I sent you this, I made some progress-
- Modified ublox plugin to identify this modem as 4g
- found out that the AT+COPS=0 you always send, does not return or return some proprietary CME code. that is because  the modem does auto-registration and sending COPS interferes with that. That is stated in the datasheet. So removed it and it everything started working.
- I do have still problems with specific devices which return error [modem0] couldn't load UE mode of operation for EPS: Serial command timed out.  I guess that’s serial port hung from some previous command?

ron

-----Original Message-----
From: Aleksander Morgado <aleksandermj at chromium.org> 
Sent: Monday, September 4, 2023 11:28 PM
To: ron <ron.jacoby at gmail.com>
Cc: modemmanager-devel at lists.freedesktop.org
Subject: Re: ublox SARA does not connect

Hey

> So its been a few months, and now when we install the product in US, trying to connect to Verizon and tmobile, I face problems again.
> Modem is ublox sara r5, which works through serial port AT commands only.
> The modem seems to be connected, when issuing AT+CGDCONT , but modem 
> manager +network manager do not go ahead to create a connection 
> Attached logs
>

The modem is indeed registered as we can see the initial EPS bearer IP address for the vzwadmin APN, but for some reason MM doesn't know about that. I can see MM trying +CREG? and +CGREG? but they both seem to return the reg state as idle.

Could you run +CEREG? manually in the AT port to see what it returns?

The modem is detected as a 1-port AT generic modem, and none of the capability queries we do end up telling us it may be 4G capable (which is why we don't try +CEREG to check)

ModemManager[573]: <info>  [1692200059.641466] [device /sys/devices/platform/soc at 0/30800000.bus/30860000.serial] creating modem with plugin 'generic' and '1' ports ...

ModemManager[573]: <debug> [1692200059.704189] [modem0/ttymxc0/at] --> 'AT+WS46=?<CR>'
ModemManager[573]: <debug> [1692200059.716311] [modem0/ttymxc0/at] <-- '<CR><LF>+CME ERROR: 100<CR><LF>'

--
Aleksander