Difference between PDA MI3 and NB1 I have this message in my keis, telling me to upgrade which says

current firmware : PDA:MI3/Phone MI4/CSC MI3

latest firmware : PDA NB1 /Phone NB1 / CSC :NB1


I am totally new to andriod apps or tabs. So don't know what does that mean, does it mean it will upgrade my tab to latest 'Kitkat'? How can i read what does the PDA,Phone,CSC code and abbrv. means?
These codes are just Samsung's own version codes, and as far as I know, they have no logic, except that they increase alphabetically and numerically with each new release. You'll have to either install and check the version they correspond to, or search for news of new firmware releases for your device to see what they upgrade.

As for the PDA/Phone/CSC, PDA is the OS itself, Phone means the Radio firmware (GSM/CDMA/UMTS/LTE radio chip) and CSC stands for Country Specific Customization (or Carrier Specific Customization), which provides regional customizations such as carrier APNs, available languages etc.