What ID is identical for all devices connected to one IoT Central app?

The Scope ID is a unique identifier that is assigned to an Azure IoT Central application. It stays constant across all devices connected to that specific IoT Central app, making it critical for scenarios where your devices must connect to the same application instance. This identifier is used for authorization when devices attempt to connect to the IoT Central application and helps ensure that devices are properly scoped to the correct application, allowing them to interact with the services and data associated with that specific application.

In contrast, the Device ID is unique for each device connected to IoT Central, meaning each device will have its own distinct identification. The Primary Key serves as a shared secret for the device primarily used for authentication, and each device also has its own unique Primary Key. The Gateway ID applies to devices that communicate through a gateway, distinguishing them from the direct device connection scenario handled by the Scope ID. Each of these identifiers has its purpose, but the Scope ID's role in uniquely identifying all devices connected to a single IoT Central instance sets it apart in this context.