i would like to know how to install a usb modem. while plugging it. linux doesn't recognize it and no action is done. i use ubuntu and mandriva. my modem is a zte corporation one.

Is this a dialup, DSL, cable, or wireless modem? Provide as much detail as you can.
After plugging in the problematic usb modem run the lsusb command from the terminal and post the output here. This will tell us if Ubuntu sees the usb modem or not.

And welcome to the LQ fourums!

If any USB device is attached to the system, there will almost 100% of the time be something which appears in the system's log files.

Can you plug the device in, and then run the following commands:

And then post the output here?

Hello and welcome to LinuxQuestions,

Please refrain from using words like urgent in your posts, it's only urgent to you and not to us who are all volunteers putting in our free time to help out Linux users with their questions and problems. As another advice, search the internet first to see if a manual is available. LQ is not the place to turn to looking for step by step guides and howtos. You'll find those on the internet in abundant numbers, for example:
setup ZTE modem Ubuntu
on the Ubuntu forums

If you have problems following a guide you've found on the internet, that's when you'll encounter LQ users at their best.

Looking forward to your participation in the forums. Have fun with Linux.

Kind regards,

Eric

2 members found this post helpful.

Please use a descriptive title for your thread excluding words like 'urgent' or 'help'. Using a proper title makes it easier for members to help you. I have changed it for you, this time.

Moreover, this thread is more suitable in Linux - Hardware and has been moved accordingly to help your thread/question get the exposure it deserves.