Enabling multiple notifications characteristic


I am a bit confused with "client characteristic configuration" that is used to enable notifications (at least in Android).

To enable the notifications I have to write to BLE device "00002902-0000-1000-8000-00805f9b34fb"

As per UART example

    mBluetoothGatt.setCharacteristicNotification(TxChar, true);
    BluetoothGattDescriptor descriptor = TxChar.getDescriptor(BleDefines.CLIENT_CHARACTERISTIC_CONFIG);

The questions are:

  1. can I controll the UUID och client configuration?
  2. how does it work with multiple notification a) with the same service b) with the different services

I was trying to find more documentation about how it work without further results. Thank you!

  • The UUID is configured on the GATT server (this can be on both a peripheral or central device). If the characteristic supports notifications or indications if will also have the CCCD (Client Characteristic Configuration Descriptor). The CCCD can be written to by a GATT client to let the server know it wants to receive notifications or indications. If you have several characteristics with a CCCD you have to enable notifications/indications on each and every one of them.