# Is modemmanager on VOXL1?

Source: https://forum.modalai.com/topic/1464/is-modemmanager-on-voxl1
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2022-10-18 12:49:18 UTC by Ed Sutter
Replies: 1 · Views: 547

## Ed Sutter · 2022-10-18 12:49:18 UTC

I'm struggling to understand how the modem link is managed/maintained in VOXL; so I have a few questions...

As best I can tell, modemmanager is not used, true?
I see the sierra.py script runs at startup (assuming voxl-configure-modem has been run prior) polling for /dev/ttyUSB2.  That's fine for startup, but what about runtime...  Is anything monitoring the link status?  
What facility/service is actually using qmi_wwan0.c in VOXL? 
Finally...
After voxl-build completes, I can see several different qmi_wwan0.c files
under the workspace.  Which one is actually used?

Thanks for your patience!

## Reply by tom (ModalAI staff) · 2022-10-18 16:32:24 UTC

@Ed-Sutter That is correct, modemmanager is not used.

As you can see in the patch here: https://gitlab.com/voxl-public/system-image-build/meta-voxl/-/blob/master/recipes-kernel/linux-quic/files/qmi_wwan2.patch

The path to the `qmi_wwan.c` file that is being modified / used is `drivers/net/usb/qmi_wwan.c`