How to access UART channel under modem manager

Embedded Linux Discussions
1

Hi,

This is a general Linux driver question. I have a cellular modem on UART port. And it is connected through modem manager. So the UARTport is opened and locked by the modem manager. Is there a way to send serial AT+ commands over the uart port while the modem manager is loaded and started, or we have to stop and quit the modem manger, and then to regain the uart port control and to send serial commands?

Thank you
David

2

Hi @dzhou, sorry i’ve never used modem manger, but taking a look at:

https://www.freedesktop.org/software/ModemManager/man/latest/mmcli.1.html

–command=COMMAND Send an AT COMMAND to the given modem. For example, COMMAND could be ‘AT+GMM’ to probe for phone model information. This operation is only available when ModemManager is run in debug mode.

Since that is debug mode only, which AT commands are you needing to send, i wonder if those are already built-into networkmanager…

Regards,

3

Hi Robert,

This is very useful and I briefly scroll down the commands there are a lot settings and configurations are on the list. I think mmcli is the answer, although it may not cover everything because new features from cell modem. Thank you for your help.

Best Regards,
David