phone retrofit

Can anyone tell me what a mobile phone compensator is and a mobile phone control unit ? I understand, I need both these items as my car is not prewired. Also, where I can get the cables(wiring harness) in order to wire a phone cradle ? If there is anything else I would need, please...

I have a C280 Estate 2006 with dvd based comand APS incorporating steering wheel controls. However, the system is not pre-wired. I have bought a Viseeo MB-2 with a view to installing in centre arm rest where I see there is a square to punch out for the contact platter of wiring to be installed...