The disclosure relates to a converter device which has a housing that can be installed into a motor vehicle. The converter device is designed to adapt an impedance of an external antenna which can be positioned outside of the housing to an impedance of at least one additional electric device via a conversion path such that a specified impedance is provided at an electric converter output. An antenna device which is independent of the conversion path is integrated into the housing of the converter device, said antenna device providing a Bluetooth and/or WLAN connection to a device, and at least one antenna device connection which is electrically connected to the antenna device is provided on the housing of the converter device as the electric output and/or electric input of the antenna device. The disclosure additionally relates to a motor vehicle comprising a converter device.