AT command for resetting the TRB142 / EC21

Networking Solutions Question
1

Due to project reason, I can’t connect the TRB142 gateway to the PC USB port to issue a gsmctl, so I’ve been trying to reset the TRB142 through the SERIAL PORT using AT command after issuing a at+QCFG=“ims”,1/2, but have not found a way that works reliably after trying for many days.

I’ve tried the following commands with different intervals and in various combinations, but they don’t work consistently.

AT+CFUN=1,1 → usual method does not work or at least does not reset the unit for at+QCFG changes to work.
AT+CFUN=4 / AT+CFUN=0, followed by AT+CFUN=1 after an interval.
AT+QPOWD=0 → returns ERROR
AT+CGATT=0, followed by AT+COPS=2, followed by AT+COPS=0 and then AT+CGATT=1

My EC21 firmware - EC21EUGAR06A07M4G

A workaround method I have used before is to make use of an AT command watchdog but the TRB142 don’t seem to have a watchdog feature that works using the the SERIAL port.

Would be greatful for any tip.

grinning_face

3

Hello @cnd75,

Our apologies for the delayed response.

If connecting the TRB142 via USB to issue gsmctl commands is not possible due to your project constraints, you could consider the following options:

  • Performing a full reboot of the TRB142 (power cycle or software reboot through the device itself) after changing the AT+QCFG="ims" setting.

  • Reboot the device remotely using the Mobile Utilities feature by sending an SMS reboot command.

  • Access the device’s CLI or WebUI remotely through RMS and perform the reboot from there.

  • You can also try executing the following AT commands:

    AT+QMBNCFG="AutoSel",0
AT+QCFG="ims",1
AT&W
AT+CFUN=0
AT+CFUN=1

The AT+CFUN=0 → AT+CFUN=1 sequence performs a modem functional restart, which is more graceful than AT+CFUN=1,1, but it is not equivalent to a full modem reboot. However, based on Quectel’s documentation and our experience with the EC21 series, it is not guaranteed to apply AT+QCFG="ims" changes, as these settings typically require a full modem reboot.

Additionally, when configuring Serial Utilities, you can create a new Console instance. This provides access to both the modem and the device’s CLI through the serial connection, which may be useful.

Please let us know whether any of these suggestions helped resolve the issue.

We appreciate your patience and look forward to your response.

Best regards,
P.