Ubuntu 22.04 LTS Linux and the Dell Wireless 5808e Gobi 4G LTE Modem

So I recently needed a broadband modem in a Dell Latitude system to work under Linux. Typically Linux does a fairly nice job of making cellular modems work in a variety of devices from embedded systems all the way up to servers. In this case, it didn’t work out of the box.

When I attempted to ask the mmcli command about the modems installed I got the dreaded “No modems found” error message. Ok. Odd. I’ve used this type of modem on a number of systems over the years with no problems under Linux. Digging a little deeper, the syslog stated:

“[base-manager] couldn’t check support for device ‘/sys/devices/pci0000:00/0000:00:14.3’: not supported by any plugin.”

Well, that’s certainly not good. Turns out that the usb_modeswitch udev rules didn’t have the exact modem device identifiers in the default ruleset. However, if I added the following to “/usr/lib/udev/rules.d/40-usb_modeswitch.rules”, everything works like a champ:

# Dell DW5808e
ATTR{idVendor}=="413c", ATTR{idProduct}=="81a9", RUN+="usb_modeswitch '/%k'"

I hope this helps some other poor sap out there who has that dreaded “e” after the 5808 identifier in their Gobi modem.