What happen to smart card access door during electrical break down?

Magnetic Electrical Plug Scam or The Real Deal?:
Query by Kelvin: What come about to sensible card access door throughout electrical break down?
You know those secured doors with wise card or magnetic card access? where you have to flash or swipe to get in?

I often wonder what will take place if there is any electrical break down?

are those point powered by battery or electrical plug?

if by battery? what come about if the battery died? will dismounting the point trigger any alarm?


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