Bluetooth version 2.1 adds the function of Sniff Subrating to save power by setting the interval between the two devices to confirm the signal transmission. Generally, after two connected Bluetooth devices enter the standby state, Bluetooth devices still need to make mutual calls to determine whether each other is still online. Of course, because of this, the Bluetooth chip must be kept at all times. Working status, even if other components of the phone have entered sleep mode. In order to improve such a situation, Bluetooth 2.1 will extend the signal transmission interval between devices to 0.1 seconds from the old version to about 0.5 seconds, which can greatly reduce the workload of the Bluetooth chip, and also allow Bluetooth to have more More time can sleep completely. According to the official report, after using this technology, the standby time of the Bluetooth device after the Bluetooth connection is turned on can be effectively extended by more than 5 times.