User manual states “Specify a time(in Seconds) you wish to keep the authentication and display for”, but I do not understand what it means?

The purpose of authentication lock:

Air traffic control room is in highly security site.  In case there is any disruption(Power outage, cable disconnected etc) of KE, customer wants it can back to service as soon as possible without needing to login and select the serve once the situation is clear.

1. The function is disabled by default. Please note after you enable the function, the Rx needs to logout and login to have the feature.
2. A Rx needs around 35-40 seconds to bootup after plugin power, so we suggest to set the value equal or greater than 50 seconds.
For example if we set it to 180 seconds, it means after power cut on a Rx, the Rx will connect back to the Tx if the power was backed in 180 seconds.
If the power was backed after 180 seconds, then the Rx shows OSD login screen rather than backs to the Tx. 

Please refer attachment for the setting.