R20 series supports two input triggers Input A/B(DOOR A/B),
and go to Intercom->Input to configure.
Input Service: To enable or disable input trigger service.
Trigger Option: To choose open circuit trigger or closed
circuit trigger. Low means that connection between Door
terminal and GND is closed, while High means the connection
is opened.
Action to execute: To choose which action to execute after
triggering.
Http URL: To configure URL, If HTTP action is chosen.
Open relay: To configure relay to open
Door status: To show the status of input signal.