# Alarm types

Alarm types are represented by icons.

### Communication alarm

No reading was received within the period defined by the communication alarm filter.

You can check the filter in the object’s [Properties tab](https://help.boomerang3.com/boomerang-3-user-manual/dashboard/object_view/detailed-object-view/properties-tab).

<figure><img src="https://3588014471-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FEANwXRnuP0ug8971viyg%2Fuploads%2FQO5zPby9A287nYv8XGgZ%2Fimage.png?alt=media&#x26;token=d971bc80-2d34-4a2e-b4cf-d7d26426b3c4" alt="Communication alarm icon"><figcaption><p>Communication alarm</p></figcaption></figure>

### Value outside warning limits

Readings are outside **warning limits** and the [Alarm Filter](https://help.boomerang3.com/boomerang-3-user-manual/dashboard/alarms_and_warnings/alarm-filter) conditions are met.

<figure><img src="https://3588014471-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FEANwXRnuP0ug8971viyg%2Fuploads%2FIZQaYg7js3i2i7WHQpG6%2Fimage.png?alt=media&#x26;token=fad8f501-7276-435e-a29c-5d0d3fe304f3" alt="Warning limit alarm icon"><figcaption><p>Outside warning limits</p></figcaption></figure>

### Value outside alarm limits

Readings are outside **alarm limits** and the [Alarm Filter](https://help.boomerang3.com/boomerang-3-user-manual/dashboard/alarms_and_warnings/alarm-filter) conditions are met.

<figure><img src="https://3588014471-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FEANwXRnuP0ug8971viyg%2Fuploads%2FslZqwgL4tK73koHVEscf%2Fimage.png?alt=media&#x26;token=5246875e-3882-4adb-bd2f-0a9820fcf604" alt="Alarm limit alarm icon"><figcaption><p>Outside alarm limits</p></figcaption></figure>