If you are a windows user and recently shifted to Linux [Ubuntu] Platform.You have a uphill task to find which method works for you perfectly and you might have tried most of the menthods using google search.Here is a simple tutorial on how to use any Datacard in Ubuntu 14.04 / 15.04.The following method works with almost all Data-card manufacturers like [Huawei Data Card, D-link Data-card,Zoook Data card ,micromax data-card,airtel 3g datacard,Basnl 3g Datacard and so on].
Steps to install or Use datacard on Ubuntu
1) Switch on the Ubuntu and plug the Datacard to your Laptop/computer
2) Now click on "Edit Connections"
3) Click on "Add" Button under network Connection window
4) Choose " Mobile Broadband"
5) Choose the "country" & "Network Operator" from the list
Note:- Don't change any setting just click on "Continue" & "Apply" whenecer required
6) A New Pop up will be shown with General , Mobile Broadband ,PPP Settings ,IPV4 Settings tabs.
7) Under "General" tab select "Automatically connect to this network" & click on "save" button for saving the settings
8) open the Dash and type "Disks" to open "Disk Utility"
9) You will have two modem Disk's named "Drive" & "CD Drive" respectively
10) Eject the one having name "CD/DVD drive"
11) Now wait for approx. 10-20 seconds "Enable mobile Broadband" will be displayed in Network manager Applet
12) Now click on Network Manager Applet & click on "Enable Mobile Broadband"
13) That's it , you are now connected to internet using Datacard/Internet Dongle
Note:- By Default Enable Mobile Broadband is not shown in the "Network Manager Applet".To get this in network Manager Applet you have to plug in the Datacard/Internet dongle in your Laptop/Computer and follow the above instructions.