Abbott FreeStyle Libre 2 User Manual page 187

prevents unauthorized devices from accessing the data if they are within range and intercept the
transmission. Under normal operation, the industry standard BLE protocols allow for many users to
be in the same vicinity. In the case where the connection is lost due to out-of-range or interference,
reconnection is only possible with the authenticated Reader that activated the Sensor.
The communication between the App and Sensor during a scan is a short range Near Field
Communication (NFC) method which makes it difficult to interfere with or intercept during
transmission. The transmitted data is protected by a proprietary data format, encryption, and
memory map. The integrity of transmitted data is ensured by a cyclic redundancy check (CRC)
generated by the Sensor and verified by the App. The communication between the App and
Sensor for Alarm data is a standard Bluetooth Low Energy (BLE) connection. The pairing of the
Sensor to the App is accomplished during activation with an authenticated login procedure that
uses an Out-of-band key exchange (NFC). This prevents unauthorized devices from connecting to
the Sensor. The transmitted data is protected by a proprietary data format and encryption. This
prevents unauthorized devices from accessing the data if they are within range and intercept the
transmission. Under normal operation, the industry standard BLE protocols allow for many users to
be in the same vicinity. In the case where the connection is lost due to out-of-range or interference,
reconnection is only possible with the authenticated App logged in to the same LibreView account
that activated the Sensor.
Quality of Service (QoS):
QoS for the FreeStyle Libre 2 Reader and Sensor wireless communications using NFC is assured
within the effective range of 4 cm between the Sensor and Reader that is specified to occur within
15 seconds. QoS for the wireless communication using BLE is assured between the Reader and
Sensor at regular 1-minute intervals. If connection is lost between the Reader and Sensor for
5-minutes, the connection lost symbol displays. If connection is lost for 20 minutes, the Reader
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