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I am using Huawei 3G USB Modem in Ubuntu 12.04 LTS on DELL Inspiron NS5520. I tried every possible solution but had no luck. Whenever my USB Modem disconnects, I can not re-connect it and then I have to restart laptop. On restart, sometimes it detects the USB Modem and sometimes not. In Ubuntu 11.x It was working fine, but now I am using 12.04. This is the lsusb ouput:

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 003 Device 003: ID 12d1:1001 Huawei Technologies Co., Ltd. E169/E620/E800 HSDPA Modem
Bus 001 Device 003: ID 0bda:0129 Realtek Semiconductor Corp. 
Bus 001 Device 004: ID 0c45:648d Microdia 
Bus 002 Device 003: ID 8087:07da Intel Corp

Any help will be greatly appreciated.

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closed as unclear what you're asking by Braiam, cuonglm, slm Jul 26 '14 at 21:48

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question.If this question can be reworded to fit the rules in the help center, please edit the question.

There's been no other real solution for me other than pull the modem out of the box and then put it back in. Am using usb-modeswitch version 1.1.7. This is not difficult, even though it increases wear and tear on the box's USB port. – Deer Hunter Jan 23 '13 at 11:56
While using usb-modeswitch I guess then Network Manager can not be used? – FishEye Jan 23 '13 at 13:08
It can, at least in my case. – Deer Hunter Jan 23 '13 at 18:15
I download and install usb-modeswitch but it could not solve my problem. – FishEye Jan 24 '13 at 18:54
up vote 0 down vote accepted

My answer is only a half solution of the problem. Maybe it could help you somewhat on Ubuntu. I am looking for a better solution.

I have the same problem on OpenSuSE 12.1 . Unplugging the modem and plugging it to a different USB port helps without a need to restart the system.

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There are commands to reset usb devices with an ioctl without unplug – Alex Aug 19 '13 at 14:15

You can run this command to diagnose how the modem is detected:

udevadm trigger --verbose

This won't solve anything but may be a useful first step in your investigation.

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I think you should restart your network manager instead of your machine.

sudo stop network-manager

sudo start network-manager

Rarely chances, might be your machine taking your modem as Mass storage device because now-a-days modem come with memory car option, use Modprobe to switch modem.

sudo modprobe option 

Note : (wait for 10 sec your modem will detect)


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