Thanks, when the system is fitted the locks in the hotel are mapped onto the front desk unit. You can issue keys for various levels with the lowest level being the guest's keycard which is only valid for their room and then individual floor access for housekeepers, then master keys for management and maintenance right up to the emergency key which is used by security which does everywhere in the hotel even secure areas like finance offices and bar cellars. The emergency keys open the rooms even if they're locked from the inside (in case the guest has collapsed).

If you lose or wipe your room key the receptionist will issue either a duplicate key or a "one shot key" (clue is in the name) but when a new guest checks in they get issued a new key. The front desk unit has a set of "rolling access codes" which match the memory in the lock so when the new arrival swipes their key the memory on the lock moves on to the next code making the old code invalid. Once this has been done 999 times it starts from the beginning again.