Hello, my name is Cyril HAENEL, and I am new on this mailing list :)
I subscribed to this list because I was looking for informations on
Quectel LTE modem, and yesterday I found this fantastic video :
https://media.ccc.de/v/33c3-8151-dissecting_modern_3g_4g_cellular_modems#t=690
I actually work on the Quectel LTE SC20 Smart module, which is
proposed with Android, but also Linux without all Android layers.
We want to use the Linux version and we use the official Quectel
Linux SDK, based on Yocto.
We can successfully build and flash the image in the module, no
problem from this side.
But the goal of this module is not to be used just as an LTE modem
for an external host, it's a standalone module and we embed our IoT
application inside.
The problem we are facing is that we don't know how to start a
broadband connection !! There is absolutely no Quectel documentation
about that, and their support is really bad, they don't help us at
all...
So we done some reverse engineering to understand how the internal
Modem is connected to main processor, how to send him AT command,
how to start data connection, etc...
We finally found and understood all methods they use (Shared Memory
Devices, qmuxd, qmi proxy, QMI protocol, etc.....).
But we are stuck to the same point, we don't find any easy way with
scripts or some utilities with config file (to set the APN for
example) to start a broadband connection :(
We flashed an Android version in the SC20 to see how it works, and
they have Android applications which connect to netmgrd, qmuxd,
etc....
But we don't have these tools under Yocto Linux, so we wondering how
we can easily set our broadband connection.
Any help or comment will be great :)
Best regards,
Cyril
--
Cyril Haenel
Registered Linux User #332632