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# HMCharacteristicValueSecuritySystemAlarmType

Possible trigger states for an alarm.

```
enum HMCharacteristicValueSecuritySystemAlarmType
```

## Topics

### Alarm Types

[`HMCharacteristicValueSecuritySystemAlarmType.noAlarm`](/documentation/HomeKit/HMCharacteristicValueSecuritySystemAlarmType/noAlarm)

The alarm isn’t triggered.

[`HMCharacteristicValueSecuritySystemAlarmType.unknown`](/documentation/HomeKit/HMCharacteristicValueSecuritySystemAlarmType/unknown)

An alarm has been triggered with an unknown cause.


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