I can make out where someone is calling dad from by how loud his voice gets when talking on phone. If its his friends here in USA, his voice is normal, while family in Bangalore a bit louder by 10 decibels. But if its his cousins from towns or his village his voice is almost 20 decibels louder. I suppose its some mental distance to voice gymnastics he plays in his head and assumes longer the distance the louder he needs to speak on the phone!