In operation, Bluetooth Smart beacons use advertising packets that include fields to indicate the beacons' identity. The smartphones use internal Received Signal Strength Indication (RSSI) to estimate distance between handset and beacons. Whilst beacons themselves only relay advertising to the smartphones and not contextual information, the smartphones use the advertising packets to determine the beacon's identity (using, for example, the phone app), and decide upon the information and/or actions that should be associated with that beacon's location.
Permitted actions will vary between phone vendors, depending on imposed limitations, but may include audible alerts, vibrations, and triggering of other apps. The nRF51822 Beacon Kit can be configured for iBeacon compatibility. The full kit includes one beacon and full access to software and design files. It leverages the ability of the nRF51822 SoC to support full Over-The-Air Device Firmware Upgrade (OTA-DFU) enabling all beacon firmware to be updated in-situ in a transparent manner.