# Device-based Network IDs

### Managing device registries in the mediarithmics platform

**Device-based Network IDs** refer to **Device Registries** because each device is assigned a "registry" where its identifiers are stored.

#### **How to active a Device Registry on a datamart**

Here are common steps to activate a Device registry on a specific datamart:

* **If you have a single datamart**, the Device Registry is automatically activated, and you can go to the next step.
* **If you have multiple datamarts**, you must manually activate the Device Registry:
  1. Go to **Navigator > Settings > Organisation > Device Registries.**
  2. Select your Device Registry.
  3. Click **More** button to open the menu.
  4. Choose **Edit linked datamarts.**
  5. **Select all datamarts** where you want to activate the Device Registry.