The CB/Comm System is two different functions, combined. The intercom is your helmet-to-helmet communications. The CB is an external Citizens Band radio, so you can talk to other radio operators, either fixed-base units, autos/trucks, or other CB equipped bikes. The two have separate settings and separate functions, which are integrated into one control, one display, and one audio system, in the Spyder.
Where you put your settings is pretty much up to your particular local conditions, and your preferences. The first thing you need to do is to go into the Preferences screen to get to your settings, to make sure your headsets are enabled. The choices are the speakers, helmets, or both. I am not sure, but I think the rear helmet volume is controlled separately, from the rear grip control. Make sure it is set up loud enough to be heard. Set your audio source (radio or iPod) speaker volume to the desired level, as a reference point. You can then turn off the audio source, if you wish. Now you are ready to set up the CB and Intercom settings.
Switch the display to the CB screen, via the multifunction control on the left handlebar. You will see four sliding scales...CB Squelch, CB Volume, Microphone VOX Level, and Intercom Volume. The scale selected, and the adjustments, are made from the multifunction switch. Squelch is usually adjusted to the point where static is heard over the CB, then back just a little, so it is quiet. This gives maximum sensitivity. If you wish to cut down some of the weaker chatter, you can set it even higher, but this makes longer distance communication spotty. CB Volume should be set to your liking, where the CB can be heard...or it can be turned down altogether...to ignore the CB and just use the intercom feature.
VOX stands for Voice Operated Transmission. Basically, when you speak into the microphone, the sound triggers the mike, and the other rider can hear you. Too high of a sensitivity, and wind noise and other stray sounds can trigger the system. Also if too high, there may be a delay before the other rider can be heard, or they may not be able to be heard at all. Too low, and your voice may not trigger the VOX, especially over the sound of the wind or engine. Adjust to where it works well for you. It may have to be changed slightly, under different riding conditions. The Intercom Volume sets the voice level heard over the intercom. If all the way down, the other rider will not be heard, basically turning the intercom off. Adjust to your liking.
I have a different comm system, so I cannot provide any additional tips or details, but this should give you an idea of what does what, so you can play with your system and get things to work for you. If these features do not work, or the CB screen in not available, see your dealer.