I was using google maps today as I drove back home from school and I received a call. Not realizing google maps was still running, I started to conversate. While talking, I heard the robotic voice of the navigation coming through the earpiece. This could be a good thing for some and a bad thing for some. In my case it was good because I would have missed a turn if it didn't keep running in the background. When the voice comes on, you will be able to hear it, but the other person on the line will not. Just thought I would share. I am not sure if this has been mentioned.