Hi Kushal,
What method do you use to create the connection for your usb modem?
The general method for Tata Photon + is to first plug in the device and wait till its "CD" icon comes up. Unmount the "CD" from your desktop itself and wait for about half a minute. Then right click on the network icon on the top bar of your desktop and amongst the various lines there will be one line that says "Create a mobile broadband connection". Follow that option and create your connection with the appropriate settings. Then again right click on the network icon. This time since there exists a connection you made, you will not get the earlier "Create....." option. Now simply select "Edit Connections" and in the mobile broadband section and check that the user name and password match your service provider's requirements. For CDMA (Tata Photon or Reliance Netconnect) your dialling number should be #777. For Tata the username and password is 'internet' for both. For Reliance it is 'device mobile number' for both. Now simply left click on the network icon and among the various connections, select the one you made for Tata and it should get you on-line.