l have the buttons there in the car on the console and near the radio.There is a dial pad and there are the call and end buttons and also on the steering wheel.l also have a bluetooth cell phone. l am confused to how to set it up so that when my phone rings l can pick it up with the keys in my car?
Thank You for your help.

What year C240 first of all?

The vehicle has to have a Benz phone kit installed first ( & not all phone kits r compatible with Bluetooth phones ). The buttons u see on the radio & on the steering wheel just mean that ur Benz is prewired for the phone kit but the kit itself is a dealer installed option.
One the phone kit is installed, u need a Bluetooth puck & that will enable any Bluetooth phone to pair with the system in the car. It is a nice system to have but l will warn u now that it is expensive.

As Jay said, the main question is how old is ur car. Only the latest models r ready for digital phones (not even mention the Bluetooth.) Older models r pre-wired for older analog phones. Start with calling Mercedes at 1-800- FOR MERCEDES & ask them about the phone system in ur car. It very well may be that u need a new kit installed, which will cost u about $2,000 at a dealer.
If u have a new car with everything installed, it is still not that simple. Some phones simply do not work with Mercedes whatever u do. Motorola works best. Call Mercedes & ask them.
l have a 2000 E320 & instead of spending $2,000 on that kit, l got a portable Bluetooth adapter for $60 & it works fine. It is not as good as the ''real'' system, but it is not bad.

Both of the previous r partially correct. A lot of the answer to ur question depends not just on the age of ur C, but on the original equipment installed. The phone buttons on the steering wheel & the keypad on the dash r standard features.

You're car is a 2005 or older (MB switched to the 280 in the '06 model year), & that would lead me to believe that u do not have the car prewired for a cell phone connection as that was a rare option on those vehicles.

Mercedes phone setups had 2 main parts back then. The first is what MB calls ''cell phone prewiring,'' which is the actual wiring from the arm rest to the head unit. If this is already installed in ur C, the rest is a lot easier (not to mention cheaper). The second part of the system is the bluetooth ''puck,'' or cradle (depending upon model year). This is the part that makes the whole system work.

The C240 would have originally needed a Motorola V60 cradle. This was an old Motorla phone that used analog signals, & u would have had to have purchased a new phone from MB for the system to work. If this cradle is already in ur center arm rest, you're in good shape. If not, some parts will need to be installed.

Mercedes now makes an adapter for the old V60 cradle that will allow MB approved bluetooth phones to work with the cradle.

Mercedes has a website that will help u address what equipment u will need to make ur car compatible, as well as which phones will work best with their system (although, l will tell u that many non-MB approved phones will work with the system).

http://wireless4mb.com/index.html

However, in all honesty, it would more than likely be a lot easier & cheaper just to buy a simple bluetooth adapter at ur local electronics or phone store.

Hope this all helps!