#include <Keypad.h>
const byte ROWS = 4;       //four rows
const byte COLS = 3;       //three columns
char keys[ROWS][COLS] = {
  {'1','2','3'},
  {'4','5','6'},
  {'7','8','9'},
  {'*','0','#'}
};
byte rowPins[ROWS] = {12,11,10,9};    //connect to the row pinouts of the keypad
byte colPins[COLS] = {8,7,6};         //connect to the column pinouts of the keypad
Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );
void setup()
{
     Serial.begin(9600);
}
void loop()
{
     char key = keypad.getKey();
     if (key)
     {
           Serial.println(key);
     }
}