HEX keypad is essentially a collection of 16 keys arranged in the form of a 4 x 4 matrix. HEX keypad usually have key representing numeric 0 to 9 and character A to F. The hex keypad has 8 communication lines namely R1, R2, R3, R4, C1, C2, C3, and C4, R1 to R4 represent four and C1 and C4 represent four column. The hex keypad is interfaced to port 1 and seven segment LED display is interfaced to port 0 of the micro controller resistor R1 to R8 limits the current through the corresponding segments of the LED display.