[Skylaw]

Knucklehead - I believe the confusion is resolved by knowing that ordering the "hands free option" gets you the wiring harnesses and the installed phone system electronics, to the point you need only to add either a puck or cradle and a compatible phone to complete the system.

Mercedes used to make prewiring for the phone system standard equipment on most of its cars. However, it stopped making it standard on many models starting with the '06 model year, and offered prewiring (only) as an option (in addition to offering the full "handsfree phone" as a second, more expensive option). Cars having the "prewiring" option still do not have the installed electronics necessary for the phone system - the Portable Support Electronics, the linear compensator for the antenna, or the mounting point (contact plate) for the puck or cradle. However, the electronics can be added later, much more easily if prewiring is present than if it is not.

To get directly to your question: You are correct in your understanding of "hands-free communication system." As to the other two, there is no difference.

Not the easiest labeling for tracking, and frankly, most sales people don't know the differences either. I don't wonder that you and many others are confused. Hope that helps.