First of all, you must have an electrical controlled door lock, either mechanical or electromagnetic lock. Our reader is built-in with a relay and which can be controlled by the response from the web server. So, when a RFID card is swiped on the reader, it will sent a HTTP request to the web server, the server will lookup from a database to check whether the RFID card is authorized to access. If yes, the server will response with a GRNT command to engage the relay inside the reader hence the reader will unlock the door lock. If not, the server will response with a DENY command and the relay will remain silence.