I switched from Huawei LTE modules to Quectel EC25.
With the Huawei modules, I could easily establish data connections over Internet only with AT commands. Is it possible to do it with Quectel ? I can establish a connection by entering some AT commands and then running Quectel-CM but I can’t do it without this software.
I’m on Linux 4.14. My device is shown like this : Bus 001 Device 009: ID 2c7c:0125 Quectel Wireless Solutions Co., Ltd. EC25 LTE modem
Modules used when EC25 is connected are : usb_wwan, usbnet, cdc_wdm, qmi_wwan, option, mii.
It is recommended to use quectel-CM.
If you do not use quectel-CM, in the case of usbnet=0, use GobiNet driver and configure qcrmcall_mode to 1, you can use AT$QCRMCALL=1,1 to set up data call, and quectel-CM can also be replaced with some open source tools like ModemManager、libqmi.
I will stick with qmi_wwan and quectel-CM. My issue is that I’m launching my wwan0 interface through ifup command and this last command from NodeJS exec() in a X11 application. Due to X11, the callback of exec() is never called because quectel-CM never exits (even tried with &, nohup, disown, sh -c). I don’t know why but it’s not specific to quectel-CM, it would happen why any software running forever in background.
But I’ve found I could use udevd to start it instead of a script in if-pre-up.d/. So it seems fine now.
Note for users wanting to use ECM (usbnet=1) :
EC25ECGAR06A06M1G → This firmware version doesn’t work well with ECM.
EC25ECGAR06A08M1G → This firmware version and newer is OK with ECM.
I didn’t try ‘07’ as I don’t have it.
That’s why I didn’t go with ECM. Updating remotely the firmware (55MB) on thousands of devices would be a pain.
I get some warnings after a few minutes from udev that it will kill the quectel-cm process because it has not exited but, in fact, it does not kill it. I use this trick on >2500 devices.