Since there hasn't been too much technical news lately, here is another thread for the curious about the XLR functions...
The XLRs steering wheel has four forward facing control switches. From left to right the switches have the following function:
1) Left most button is labeled with a "talk icon" on top and SRCE on the bottom. Pushing the top part of the button enables voice commanding, while pushing the bottom part changes the audio/video source.
2) The right button on the left side is labeled "GAP" with a '+' and '-' indicator on the top and bottom, respectively. This sets the gap between cars with the adaptive cruise control.
3) The left button on the right side is labeled by a "wedge icon" with a '+' and '-' indicator on the top and bottom, respectively. This raises and lowers the audio system's volume.
4) The right most button is labeled with "1/6" with a '+' and '-' indicator on the top and bottom, respectively. This allows for seeking of radio stations as well as CD-changer track and DVD chapter changes.
In addition to the steering wheel controls, behind the steering wheel are two GM stalks.
5) The left-most stalk controls enable the cruise control as well as turn signals.
6) The right-most stalk controls wiper functions, including the automatic rain sensing function.
(Note : Edited on 10/8/03 to fix right hand steering wheel button description.)