Often need to reboot before USB modem is recognised on laptop

frank4360 · 06-18-2010, 11:21 AM

I run Ubuntu 9.10 on a PackardBell laptop with a Zoom USB modem for dial-up Internet access.

Many times the modem is not recognised by Gnome PPP and the only solution I have found is to reboot the computer.

Has anyone got a better idea how to get the system to find the modem without rebooting?

Thanks in advance

mazinoz · 06-18-2010, 04:39 PM

Have you tried just turning modem off, unplug, replug, turn modem on? Sometimes works for me - it may take a few seconds to do it though.

frank4360 · 06-18-2010, 11:40 PM

Yes - the modem is powered by the USB connection. Unplugging, replugging either to the same USB port or another makes no difference!

Is there anything I can use on the command line to force Linux to rescan the device, I wonder?

mazinoz · 06-19-2010, 08:52 PM

Could try: lsusb and see if modem is listed.

Also maybe post output of: dmesg that then occurs.

If you like maybe try installing kppp the KDE brother of gnome-ppp. It has a tab on modems and shows the output when a modem tries to connect.

Another gotcha is you may need to create a symbolic link as follows:

ln -sf /dev/ttyS0 /dev/modem (from memory) to create a serial connection, before running gnome-ppp.

frank4360 · 06-20-2010, 11:59 AM

Thanks Mazinoz

I tried installing kppp, but I get the same problem; the system says there is no modem on the system, so there is no information from attempts by the modem to connect to the ISP!

Next time the problem occurs I will run lsusb.