<![CDATA[USB Modem is always down]]>I am trying to setup a multi-WAN setup using USB mobile broadband.

The modem I am using is Huawei E5372 and it is listed in the known working modems.

I tried to connect the device but seems to be always down.
OPT2-down.png

I also tried to connect directly to the device using a smartphone to verify the connection and it is connected to the internet.

Did I miss something that was not on the modems documentation?

Looking forward to any help on this from you guys.

]]>https://forum.netgate.com/topic/164146/usb-modem-is-always-downRSS for NodeMon, 16 Mar 2026 20:59:09 GMTWed, 02 Jun 2021 13:11:08 GMT60<![CDATA[Reply to USB Modem is always down on Fri, 04 Jun 2021 14:11:41 GMT]]>Further investigation

I issued the statement via shell

usbconfig

It then displayed:

ugen0.1: <Marvell XHCI root HUB> at usbus0, cfg=0 md=HOST spd=SUPER (5.0Gbps) pwr=SAVE (0mA)
ugen1.1: <Marvell EHCI root HUB> at usbus1, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=SAVE (0mA)
ugen0.2: <HUAWEI Technology HUAWEI Mobile> at usbus0, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=ON (500mA)

I then checked those devices:

ls -l /dev/ugen*

It then displayed:

lrwxr-xr-x  1 root  wheel  9 Jun  4 21:44 /dev/ugen0.1 -> usb/0.1.0
lrwxr-xr-x  1 root  wheel  9 Jun  4 21:43 /dev/ugen0.2 -> usb/0.2.0
lrwxr-xr-x  1 root  wheel  9 Jun  4 21:44 /dev/ugen1.1 -> usb/1.1.0

The USB device is on /dev/ugen0.2 but the Netgate device's PPP is only acknowledging /dev/cuau0

I also tried editing the file /etc/ppp/ppp.conf and tried to replace anything the says "cuau*" into "ugen*" to test if it is about the configurations. I rebooted the device and after it was on, Netgate still just recognizes /dev/cuau0 on the PPP lists and not /dev/ugen0.2

Do you guys know what could be done to solve this? Any hint or direction is much appreciated 😄

]]>https://forum.netgate.com/post/986214https://forum.netgate.com/post/986214Fri, 04 Jun 2021 14:11:41 GMT<![CDATA[Reply to USB Modem is always down on Thu, 03 Jun 2021 19:18:40 GMT]]>@abelcallejo
"Device busy" let me suspect that any other process had accessed it before and occupies it still. So possibly there might be something in the log accessing /dev/cuau0?

Maybe @stephenw10 can tell, what's going wrong with it. He is the hardware guru here. 🙂

]]>https://forum.netgate.com/post/986129https://forum.netgate.com/post/986129Thu, 03 Jun 2021 19:18:40 GMT<![CDATA[Reply to USB Modem is always down on Thu, 03 Jun 2021 00:09:13 GMT]]>@viragomann

Some hints from the logs:

MODEM: Fail to open serial port /dev/cuau0 on speed 115200

can't open /dev/cuau0: Device busy

Here is the full version of a certain batch

Jun 3 08:02:07	ppp	43386	[opt2_link0] Link: reconnection attempt 23 in 2 seconds
Jun 3 08:02:07	ppp	43386	[opt2_link0] LCP: Down event
Jun 3 08:02:07	ppp	43386	[opt2_link0] Link: DOWN event
Jun 3 08:02:07	ppp	43386	[opt2_link0] MODEM: Fail to open serial port /dev/cuau0 on speed 115200
Jun 3 08:02:07	ppp	43386	[opt2_link0] can't open /dev/cuau0: Device busy

I looked it up online but found nothing useful. Is this something that needs to be overridden via shell?

]]>https://forum.netgate.com/post/986021https://forum.netgate.com/post/986021Thu, 03 Jun 2021 00:09:13 GMT<![CDATA[Reply to USB Modem is always down on Wed, 02 Jun 2021 17:52:24 GMT]]>@abelcallejo
Take a look in the logs for hints what's the issue.

]]>https://forum.netgate.com/post/985963https://forum.netgate.com/post/985963Wed, 02 Jun 2021 17:52:24 GMT