Many a time we get missed calls/calls /SMS from unknown number , we can use this app to find the location and service provider of caller.(without Internet Connection) Get the Telecom Circle (State / Metro) and the Operator of any mobile number by just entering first 4 digit of your Mobile Number. It doesn't tell only the telecom circle but also tells which area that telecom circle includes. see the screenshot. Get the STD code of any city in India. Get the ISD code of all the countries.