RFID (Radio Frequency IDentification) is the process of using a radio wave to unlock a door – at least in this case. There are other uses, but I will focus on the door aspect. RFID requires an RFID card, or RFID chip to be placed over a reader. If the system recognizes the RFID code, it will unlock the door for 5 seconds so you can enter. If it doesn’t recognize the code, then the door will not unlock, and access is denied. In addition, RFID systems allows for time settings. For example, if you had a dog walker, you could give the walker a key card, and set it to unlock with that code only between the hours of 8AM – 12PM. Before 8AM, and after 12PM, the door will not unlock for the walker. There are a number of options that can be used, but I am sure you get the picture.