GeoVision GV-EBX1100 Series Firmware Manual page 99

6. To trigger an alarm when the scene turns dark, e.g. when the lens of
camera is covered, make sure the Alarm for Dark Images option is
enabled. By default, this function is enabled.
7. Click Apply to save all the settings.
8. Start monitoring to enable the function. To have output alarm, it is
required to start Input monitoring. See 4.5 Monitoring.
When the camera has been tampered, the output device can be activated.
To turn off the output device immediately, return to this setting page, and
click Restart Detection.
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