A user interface 4 for a communication system 2 in a motor vehicle 1 which, in a restricted operating mode, restricts a functionality of a radio interface 3 for wireless connection to a radio communication network and to a communication system 2 for a motor vehicle 1 with a radio interface 3 for wireless connection to a radio communication network and for setting up a corresponding communication link, and to an associated operating method. The user interface 4 activates a waiting function 4.1 for an incoming call in the restricted operating mode, which informs the caller of the cause and/or expected duration of the operation with restricted functionality.