U620L Novatel

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Config Background

Available modes of the device are RNDIS and CDC-ECM.

RNDIS is a Microsoft proprietary protocol used mostly on top of USB. It provides a virtual Ethernet link to most versions of the Windows and Linux operating systems. A partial RNDIS specification is available from Microsoft, but Windows implementations have been observed to issue requests not included in that specification, and to have undocumented constraints.

CDC-ECM is Ethernet over USB.[1]

Device Modes

End-User Mode: Enumerating CDC-ECM interface - In this mode, the device is used for a WWAN connection to the Internet for such activities as browsing or connecting to a VPN.

pacman -Sv usb_modeswitch
sudo usb_modeswitch -v 0x1410 -p 0x9020 -u 2
ip link
sudo dhcpd in73rf4c3

Enterprise Mode: Enumerating CDC-ECM and Modem interfaces (Optional) - In this mode, the Modem interface allows users to send AT commands to the device to configure, query, or manage the Internet connection.

I do not understand Enterprise mode, they say CDC-ECM AND modem interfaces? Does it give both interfaces at once? The guide asks you to compile option.c and usb-wwan.h which are definitions for USB serial mobile broadband cards. It just involves adding a driver line that associates the device with the driver.

udev rule

nano /etc/udev/rules.d/99-vzw_u620l.rules
SUBSYSTEM=="usb", ATTR{idVendor}=="1410", ATTR{idProduct}=="9020", ATTR{bConfigurationValue}=="1", ATTR{bConfigurationValue}="2"


sudo udevadm control --reload

Notes: https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=121326&p=819522


Creating an Auto-eject rule: http://sysmagazine.com/posts/187702/

U620L - Set CDC-ECM Permanently

I contacted Novatel and they would not tell me how to do this/Said that their was no way to do this.

Put into CDC-ECM Mode

  1. Go to:
  2. Click Debug Mode
  3. You will have to restart your modem so unplug and re plug I usually wait at least 10 seconds before unplugging and 15-30 seconds before plugging back in
  4. By default the modem will not work in Windows as Windows does not like this mode. Plug into a linux box or BSD box though and ask for a DHCP request and everything is cool!

You should still be able to access the web interface after this.

Take out of CDC-ECM Mode

  1. Plug into linux box or a box that interacts with CDC-ECM mode.
  2. Grab a DHCP release so we have access to the correct network (I think it uses NAT redirection)
  3. Go to:
  4. Click End User Mode

Research Study

I hope that they do not disable this feature in an update. I also wonder if having the modem in diagnostic mode disables firmware upgrades so I am going to track some firmware versions:

Modem A

Current Software Version: 1.3 (L1.218.1 M9x25MET-2.44.3 1 [2015-05-13 13:56:54])

Configuration Version: I14.NVT,USB620.0

Modem S

Current Software Version: 1.3 (L1.218.1 M9x25MET-2.44.3 1 [2015-05-13 13:56:54])

Configuration Version: I14.NVT,USB620.0


  • I do not see a way to tell if the device is in debug mode
    • This also gives you serial access too: screen /dev/ttyACM0 115200
    • I do not know the password
  • https://en.wikipedia.org/wiki/Ethernet_over_USB