Laird Connectivity is now EzurioAnswer
In Bluetooth, "class" refers to the three levels of power for Bluetooth devices: Class 1, 2, and 3. The following table compares power and range of these three classes:
| BT Class | >Maximum Power | Operating Range |
|---|---|---|
| Class 1 | 100 mW (20 dBm) | 100 meters |
| Class 2 | 2.5 mW (4 dBm) | 10 meters |
| Class 3 | 1 mW (0 dBm) | 1 meter |
To communicate over the 100 meter range, a class 1 BT device is required at both ends. To communicate over the 10 meter range, a class 1 or class 2 device is required at both ends.
Note: Class 3 devices are uncommon due to their very limited range.