This combination lock can be "unlocked" by entering a 3-digit secret code (720 possible combinations)
HOW TO USE :
To lock : ( energizing the relay) Press any key except the key corresponding to the first digit of the secret code.
To unlock : (de-energizing the relay) Enter the secret code thru the keypad. Each digit must be entered with the correct sequence. The relay will be de-energized once the correct code is entered