Abstract: The invention relates to a marker element, in particular a medical or surgical marker element, for a referencing unit of a navigation system, which marker element is configured to be reflective to electromagnetic radiation, further comprising a layer comprising a multitude of retroreflective elements. An improved referencing unit and an improved navigation system are also provided.

Abstract: A data communication device includes: a computation unit and data unit which includes a first radio communication module for wireless data exchange with an external radio device or is connected to the first radio communication module, a second radio communication module which communicates wirelessly with the external radio device, and a memory that stores identification data from the first radio communication module. The first radio communication module is operated in a receiving mode in which the first radio communication module is not detectable by the external radio device. Upon receiving identification data for the first radio communication module from the external radio device, the first radio communication module can establish a connection and for subsequent data exchange with the external radio device. The second radio communication module is operated in standby mode in which the second radio communication module waits for a communication query from the external radio device.

Abstract: A data communication device includes: a computation unit and data unit which includes a first radio communication module for wireless data exchange with an external radio device or is connected to the first radio communication module, a second radio communication module which communicates wirelessly with the external radio device, and a memory that stores identification data from the first radio communication module. The first radio communication module is operated in a receiving mode in which the first radio communication module is not detectable by the external radio device. Upon receiving identification data for the first radio communication module from the external radio device, the first radio communication module can establish a connection and for subsequent data exchange with the external radio device. The second radio communication module is operated in standby mode in which the second radio communication module waits for a communication query from the external radio device.