A quick look for some professional vocabulary in bluetooth:
Profile can be understood as a specification, a standard communication protocol, which exists in the slave device. The Bluetooth organization specifies some standard profiles, such as HID OVER GATT, anti-lost devices, heart rate monitors, and more. Each profile will contain multiple services, each representing a capability of the slave device.
It can be understood as a service. In a ble peripheral device, there are multiple services, such as a power information service, a system information service, etc., each of which contains a plurality of characteristic feature values. Each specific characteristic feature value is the subject of ble communication. For example, the current power is 80%, so the characteristic value of the battery will exist in the profile of the peripheral device, so that the central device can read 80% of the data through this characteristic.
Characteristic characteristic value, ble master-slave communication is realized by characteristic, can be understood as a label, through which you can get or write the desired content.
UUID, unified identifier, the service and character we just mentioned need a unique uuid to identify
Each slave will have a thing called profile, whether it is the custom simpleprofile above or the standard anti-lost profile, they are composed of some columns of services, and then each service contains more A characteristic, communication between the master and the slave is achieved through the characteristic.