Actually, 'your' phone line is shared with atleast 5 other people.
In Physics were learnt that the line switches between user's every couple milliseconds, so your data is sent, then ur neighbour's, then all the other people using their phones down your street, then eventually it gets back to you, ofcourse, you don't notice it, because you can't here at the millihertz level.
Apparantly, that has something to do with physics