Electrical built-in installation device for a mobile audio device

The device (1) has a built-in insert (3) comprising a supporting ring (4) and a built-in flap (5) connected with the ring. A holder (15) is provided with a hole for accommodating a centering mandrel and a holding device for a mobile audio device. A printed circuit board is arranged at a lower side of a base plate (26) that connects a front plate (16) and a counter plate (17), and a central disk (27) has a recess for clamping the holding device. The circuit board has an electrical connection with the audio device over a plug device and with the insert over another plug device.