July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Controlling Functions And Menu Selection Using The Steering Wheel Buttons

See:

Design and Function, audio module (AUM) Applies to the S60, V70, XC70 and S80
Design and Function, Road traffic information system (RTI). Applies to the S60, V70, XC70 and S80
Design and Function, multimedia module (MMM). Applies to XC90
Design and Function, engine management system
Design and Function, phone module (PHM).