I installed ND-BT1 for my Z1 (updated to Z3). I got it paired with my phone (Casio G'z One Bolulder) and my wife's phone (Blackberry Storm) on the first try and even uploaded both of our phone books without any problems. The calls are loud and clear on both ends (I had to relocate my mic).
But, I am not getting a ring through the car speakers with either phone. I even turned the ringer volume all the way upon on the headunit and still nothing. Anybody have any ideas?