How do they do that?

[Coxall8395]

My E46 M3 had a great device which bleeped through the sat nav stereo as you approached a fixed speed camera and bleeped even louder if you were going so fast you would get flashed. It even knew when new temporary average speed cameras were put in from time to time and would bleep madly if you went too fast.

Some might think this annoying but it saved me loads of times.

What was it, how did they do it and how did it learn new sites?