Thanks guys for the quick reply!
I have 2003 A6 4.2 with On-Star, factory (useless) navigation and integrated phone cradle (in arm rest compartment), but no actual Motorola phone (missing).
I am planning in the future to upgrade my Navi to RNS-E and would like to have Bluetooth module as well. I saw this module (4E0 862 233 B) on e-Bay and its say that this is telephone/Bluetooth module from Motorola for Audi's. There are a few similar modules for sale; some of them with Motorola phone as well, some w/out. Part numbers 4E0910333C, 4E0910333B or 4E0862233B. Can I use one of those modules? What is MOST stands for? Any help will be greatly appreciated!
Thanks in advance!
You have a "old style" A6 (called C5 or 4B platform) and any 4E0 or 4F0 part will be completely useless in your car. Check the quick links, there are several references to replacing OnStar with Bluetooth.