Brief description of components: Identifiers
WARNING: This page is about a different car, the 2013 BMW X5, 2012 BMW X5, and 2011 BMW X5. However, it is still accessible from the selected car via links, so may be relevant.
Alongside the normal functions of the radio remote control, the identifiers have a radio receiver. The radio receiver enables a response on the part of the identifier to a radio signal from the transmitter antennas of the vehicle.