Just read the following from MB UK site, which answered my question
"The new C-Class Saloon is the first Mercedes-Benz to receive Bluetooth voice connectivity as standard. Even while you are on the road, you can remain fully contactable.
This uncomplicated system allows quick connection to most Bluetooth compatible handsets. Any incoming calls can be accepted at the touch of a button for safe and clear calls over the vehicle’s speaker system. You can also make calls using the call list, keypad, previously stored business cards, or by entering the required number on the headunit.
With the addition of optional telephone pre-wiring and an accessory cradle you’ll enjoy even further convenience. Whilst in its cradle your mobile phone will be charged, you’ll be able to make and receive calls, and access the sim telephone address book automatically to make calls using the central controller dial, multi-function steering wheel or Linguatronic voice control (where fitted). "
"The new C-Class Saloon is the first Mercedes-Benz to receive Bluetooth voice connectivity as standard. Even while you are on the road, you can remain fully contactable.
This uncomplicated system allows quick connection to most Bluetooth compatible handsets. Any incoming calls can be accepted at the touch of a button for safe and clear calls over the vehicle’s speaker system. You can also make calls using the call list, keypad, previously stored business cards, or by entering the required number on the headunit.
With the addition of optional telephone pre-wiring and an accessory cradle you’ll enjoy even further convenience. Whilst in its cradle your mobile phone will be charged, you’ll be able to make and receive calls, and access the sim telephone address book automatically to make calls using the central controller dial, multi-function steering wheel or Linguatronic voice control (where fitted). "