The Dead Time in the Detection menu defines the minimum time between two reads of the same chip.
In the passive legacy mode Detection every dt ms and when using the active system, the decoder simply ignores further reads of the same chip for the duration of the dead time, after a first read has been stored.
In the First detection only, Last detection only, First + last detection modes that were introduced in more recent versions of the firmware, the decoder checks if the chip is still in range for the duration of the dead time after a first read has been stored.
The default value of the dead time is 5000ms. It can be set to value between 0 and 9999ms.