Abstract: Method for transmitting a data stream between a mobile data carrier and a playback device, in which authentication data for setting up a second transmission channel from the data carrier to the playback device is transmitted via a first transmission channel set up between the data carrier and the playback device by an electromagnetic field emitted by the playback device. Following verification of authentication data, the second transmission channel is set up, via which the data stream is transmitted from the data carrier to the playback device by a radio signal from a transmitting antenna of the data carrier. The power supply to the transmitting antenna is provided via the first transmission channel, and the second transmission channel is maintained only as long as the first transmission channel is maintained.