A beacon is a small transmitter that transmits signals with a range of up to 40 meters on the Bluetooth low-energy standard. Beacons send a signal at a specific time interval that can be assigned by the correct receiving device. In most cases, the device is a smartphone or tablet with the corresponding app. In the signal, an ID is transmitted with which each beacon can be identified. There is a distinction between the standards iBeacon (Apple) and Eddystone beacon (Google). Eddystone beacons can, unlike iBeacons, send an URL.