Abstract: The invention relates to a retaining device for the purpose of mechanically and electrically connecting a mobile user device, in particular a mobile radio telephone or a PDA, to a vehicle.

Abstract: The invention discloses a mobile telephone device as part of a hands-free device in a motor vehicle. Known mobile telephone devices can be expanded only to a limited extent in their functions and functionalities by connecting peripheral devices such as for example headphone-microphone combinations. The new mobile telephone device is to be flexibly expandable by components or functionalities. For that purpose a base member (1) has a receiving means (8) for receiving a module unit (20). The module unit (20) is conductingly connected to the control device by a connecting device (21) with contact elements at the module side and contact elements at the receiving means side. The module unit (20) has analog and/or digital function units and/or analog memory units. The module unit can be for example in the form of an expansion card or memory card. By inserting a module unit (20) into the mobile telephone device it is expanded by the function which is predetermined by the respective module unit (20).