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Your hotel room lock has no network and never asks reception whether your card is valid. It runs on four AA batteries, and your card carries a sequence number. The lock opens only if that number beats the highest it has seen, then stores yours as its new high-water mark. That is what kills the previous guest's card. #techtok #hereswhatyouneedtoknow #hotelkeycards #accesscontrol #learnontiktok