# Bluetooth LE Characteristic Set Notification

Subscribe to a characteristic provided by a BLE device.

Action available for the following operating systems:

![](/files/kfMeq0OanEe5OOx5RmUn)

### Parameters

*Targets*

* Service UUID *\<string>*
* Characteristic UUID *\<string>*
* Notification State:
  * 0 - *Disabled*
  * 1 - *Notify* - Notification don't need acknowledged, so they are faster. Hence, server does not know if the message reach to the client.
  * 2 - *Indicate* - Indication need acknowledged to communicated. The client sent a confirmation message back to the server, this way server knows that message reached the client. One interesting thing defined by the ATT protocol is that a Server can't send two consecutive indications if the confirmation was not received. In other words, you have to wait for the confirmation of each indication in order to send the next indication.
* **Target for Service UUID** <*unquoted string*> - Control or variable.
* **Target for Characteristic UUID** <*unquoted string*> - Control or variable.
* **Target Value** <*unquoted string*> - Control or variable.

{% hint style="info" %}
If monitoring multiple characteristics, targets must be the same for all characteristics.
{% endhint %}

{% hint style="info" %}
For more information that helps the use of this action you can consult the following links:

<https://www.bluetooth.com/specifications/gatt/services/>\
<https://www.bluetooth.com/specifications/gatt/characteristics/>
{% endhint %}


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