Cebek DA-04 module is a intelligent circuit, that when connected to the bell push of a front door it is able to memorise a melody played on it and to record it. Once this operation done, the module will only allow the door to open when the person who press the bell plays the exact melody previously recorded. Otherwise, the bell will act and ring as a normal bell. The output time is adjustable between 1 and 4 sec. It includes an auto-blocking against failed access attempts, outputs to open door, push button for the ring and LED's.