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I am using Ubuntu 12.04 . I will explain my situation first .

I am using A USB modem which frequently disconnect for an hour or so. Then i will plug off it from ports and will insert again .Then it will search again and connect .

My idea is , is there anything i can do else without plugoff the modem from USB ports , i mean restarting powersupply to modem or USB port .

One more point: I can't restart total USB's power-supply because my speakers are USB and sometimes i used to work by attaching the USB devices .

Help me guys , if i got this then you are going to save me from an daily exercise .

Thank you .

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up vote 3 down vote accepted

usb-modeswitch Install usb-modeswitch

We can try if a reset of our USB device helps resurrecting it. We first need to find out the vendor ID, and the product ID easiest by


This will give information e.g. like follows:

Bus 003 Device 002: ID 04f9:0224 Brother Industries, Ltd

In this example the vendor ID is 04f9, product ID is 0224 (right, its my printer).

To reset the device we may then issue

sudo usb_modeswitch -R -v <vendor ID> -p <product ID>

For more options read the manpage or the project homepage.

Install via the software center

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I have looked in synaptic , i got it installed already . – Raja Sep 25 '12 at 18:55
Sorry for that - now it should do. – Takkat Sep 25 '12 at 18:58
Just a note - in case the modem hangs it may not even react on a reset command - but worth a try anyway. – Takkat Sep 25 '12 at 18:59
hey , if device rstarted means again it have to ask me password of gsm sim but its not asking . i think its not doing . here is the link – Raja Sep 25 '12 at 19:02
Sorry to read that. It did reset: OK, device was reset. If that did not help I have no really good further idea. I hope someone knows if it is possible to power-off an USB-port by software. I doubt it will work (e.g. my USB-ports here are always powered ON even when I powered my machine off). – Takkat Sep 25 '12 at 19:09

You are probably using usbserial driver to activate the usb modem, it's a driver used for testing

Try the option driver

USB driver for GSM and CDMA modems (USB_SERIAL_OPTION)


Say Y here if you have a GSM or CDMA modem that's connected to USB.

This driver also supports several PCMCIA cards which have a built-in OHCI-USB adapter and an internally-connected GSM modem. The USB bus on these cards is not accessible externally.

Supported devices include (some of?) those made by: Option, Huawei, Audiovox, Novatel Wireless, or Anydata.

To compile this driver as a module, choose M here: the module will be called option.

If this driver doesn't recognize your device, it might be accessible via the FTDI_SIO driver.

You can use it like this:

modprobe option
echo VENDORID PRODUCTID > /sys/bus/usb-serial/drivers/option1/new_id
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