Track the mobile calls without an internet connection

We all have got missed calls from an unknown number and wondered from whom it was or from where it originated.No more guess with true caller (India).This app for android ,which works only in India,tells you the location from where the call originated :not just the state or city,but even the telecom circle and telecom operator  of the caller.There is no need for internet connection for this app to work.It also syncs with your all google contacts .you can also find out the STD or ISD code of cities ,and conversely find out the city from the STD or ISD code.