One note:
We found that most users like to set the tilt stand to a very flat position, that way they see the screen better. If you look at the phone you will note that the microphone is on the bottom, this is bad for reception. The more the phone is perpendicular to the surface it sits on, the worse we have found the mic quality to be. I also remeber this being noted somewhere in some documentation on the 7660. Try setting the phones so that the microphone is not facing directly into the table.
