But, to start the communication, it is necessary to establish a connection through an App or a specific website. QR code reading QR codes also allow you to connect with customers. This strategy is more passive than the previous ones, since potential phone number list consumers must make the decision to scan the barcode with their smartphone. Beacons Beacons are small devices that emit a Bluetooth signal, whose maximum range is 50 meters and are capable of defining a location and detecting or locating other devices, such as a Smartphone that has a Bluetooth signal tracking application. beacon.