I always heard the ringing. Not only that, but when you hit "end call" on the TomTom, you even hear the sound the cell phone usually makes when you hang up. I thought that was pretty cool.
I just found that when I initiate the call from the TomTom screen, I can hear the ringing through the TomTom speaker.
But when I initiate the call from my iPhone, I hear silence when it should be ringing, then the TomTom speaker only makes sound after the other person answers.
Why would it matter which device initiates the call?