Mobile Broadband Issues 2


mmcli sees the modem, says it’s registered, discovers the available networks. It says it successfully activated the modem when asked to, but still - no success in establishing a connection.

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Hi, sorry take long to reply. I tried to find my old modem (but with different brand) to replicate. But when I found it, the modem locked by the ISP and the ISP already bankrupt :joy: nothing I can do to replicate it.

But looking to your modem product ID 0031 from vendor ID 19d2, there another page on internet from archlinux wiki that maybe you could try here.

Hello @lyubo ,
Is this an ADSL or VDSL modem? If so I think you will likely need to make a PPOE connection through it to your ISP. At least that is the case whenever I had done it for myself or others. Mostly I would just put a router between the modem and the pc since the network is shared in the house and the modem was normally located far from the desk with the PC.

I’ll answer that as I have the same issue. This is a ‘mobile broadband’ USB modem, ie using the 2G/3G/4G cellular networks. Yes, a PPP connection is required, but up until F35, Network Manager would set that up automatically.
This process is now failing for some reason.
I suppose I could try to do this manually with AT commands, as we would have done 20 years ago but I try and be a normal user these days. :slight_smile:

Possibly …

sudo usb_modeswitch --<mode to apply> --default-vendor <Vendor ID> --default-product <Product ID>

Run lsusb first to get modem id

I need more information on the --<mode to apply> section.

After following the instructions I get Cannot open /dev/ttyUSB0: Device or resource busy. Same goes for ttyUSB1 and ttyUSB2.

I really feel we’re looking in the wrong direction here. We’re trying to configure a device that was already automatically properly configured by the system. It seems to me that either some package went broken or was removed or replaced, or something corrupted the communication between two or more software instances.

If you’re sure it’s already configured properly, the last part should be configuring the dial service. On Fedora default configuration, with network manager and modem manager you could run nm-connection-editor. From there you could add new connection, select mobile broadband and after that it will show up some configuration specified for each countries and specified for each ISP operator.

If you still having the problem then you could try to run systemctl status ModemManager or systemctl status NetworkManager to see if there any error reported.

I’ve tested on a live Fedora 35 WS installation out of a USB stick to see if it would connect or give some other information – I got the exact same result, errors, and output. The modem still works on the other laptop and at this point I officially have no idea what might be going on so I will just remove wvdial and set usb_modeswitch back to its defaults and leave it. Maybe some future system update will make it work again. I will also consider getting a new modem as this one is pretty old already and only supports 2G/3G networks.
Thank you all for your help!

Interesting that a new install doesn’t work, but I suspect a new modem won’t help much either as my 4G modem is comparatively new.
I’m away from my modem for a couple of weeks but will try to do some more experiments when I get back.
If this was going to be fixed, I would have thought it would be done by now, but it strikes me that we may be the only 2 people in the world that use a dedicated USB Mobile Broadband modem with Fedora. I suppose most people use their mobile phones with wifi hotspot these days.

Hello @mikew02 & @lyubo ,
As @oprizal pointed out, for this you use ModemManager and the documents for a cellular modem connection can be found at Pay no attention to F17 release level since the instructions have not changed since for this particular technology (2G&3G). It should be really just making the final part of the connection, the account negotiation, to get connected. Since you both can query your hardware from the system level.

I just upgraded my system to Fedora 36 and straight away, without me doing anything about it, the modem works again just as it should and as if there was never any problem.
So I confirm that my issue (inability to connect to the internet and have mobile broadband via my USB modem) was introduced with the upgrade from F34 to F35 and is no longer present after upgrading from F35 to F36.

Thanks for the update and I was really, really hoping that upgrading to F36 would work for me as well, but unfortunately not. I get the same behaviour as with F35. :frowning: