A system for transmitting signals, including a device for transmitting data between a movable and stationary portion of a windmill, to be installed on either portion, and including: connection elements for connecting at least one wireline to a plurality of groups to receive a plurality of respective data flows, each flow coming from a corresponding apparatus installed on the mobile portion or stationary portion; elements for processing the received streams, configured to assign a priority parameter value to each received stream, and in the event of concomitant reception of multiple streams, to compare the values of the priority parameter that are associated with the received streams and transmit by priority to a module for transceiving the radiofrequency signals, with a view to a radiofrequency transmission to the other of mobile or stationary portion, the stream associated with the value of the priority parameter corresponding to the highest degree of priority.