Switching ONVIF mode to “Undiscoverable,” and it means users
must program ONVIF’s URL manually.
The ONVIF’s URL is:
http://IP_address:8090/onvif/device_service.
Go to Intercom - Relay to configure relay settings.
There are three terminals of relay: NO, NC and COM. NO stands
for normally open contact. NC stands for normally closed contact.
Relay ID: E21A/V supports two relays. Users can configure them
respectively.
Relay Type: Default state means NC and COM are normally closed,
while Invert state means NC and COM are normally opened.
Relay Delay: To configure the duration of opened relay. Over the
value, the relay would be closed again.