I have just installed fedora 21. I want to know how can I use my tata docomo fton wifi in fedora 21?

Configure wifi in the network manager.

This similar question has been asked and answered MANY times on this site already....please try to use the LQ search function, or check Google. That dongle is typical of most wireless devices, in that it needs to be 'flipped' to become a modem first. Install usb_modeswitch from the Fedora repositories, and run it. It will turn the device from a storage device to a communications device. From there, you will be able to use network manager or another program (wvdialconf, for example) to configure it.

---------- Post added 02-05-15 at 10:17 AM ----------

..which will NOT WORK, since the device is a storage device when inserted, and as such, won't show up under network manager until it's flipped.

He said wifi and not 2g or 3g dongle.

...and if you bothered reading or understanding the answer, you would have seen the term 'wireless'. Neither 3g or Wifi have wires, do they??? The Tata device is STILL a storage device when inserted. Before using network manager or ANYTHING ELSE, you need to flip it to become a communications device.

Read ANY of the ample documentation on these Tata devices and how to make them work with many versions/distros of Linux.

Do usb wifi cards not 2/3G need to use usb_modeswitch. Most wifi b/g/n/ac in laptops don't need usb_modeswitch.

..and the OP is NOT ASKING about most wifi; the device they posted about needs to do this. Again, there is MUCH documentation on that device, ALL of it says you need to do this. AGAIN, Tata puts their drivers on a storage device embedded in the unit...when you plug it in, it shows up as a storage device, NOT WIFI, NOT MODEM, NOT COMMUNICATIONS OF ANY TYPE. Running network manager at that point WILL DO NOTHING, so telling the OP to do this won't get them anywhere, until the device is able to function.

Please, don't post misleading/incorrect answers.