D-Link DVS-210-1 User Manual page 36

Trigger D/O:
Select this option to trigger the digital output for a specific number of seconds when an event occurs.
Server: Specify the location where the event information should be saved to. This option will not be available for the Network
Lost trigger.
SD:
Select this option to record to an SD card that has been inserted into the device.
D-Link DVS-210-1 User Manual 36