Клавиатура 4х4 в Ардуино

Может кто-нибудь объяснить мне, что означает этот код:

byte rowPins[numRows] = {9, 8, 7, 6}; //Rows 0 to 3
byte colPins[numCols]= {5, 4, 3, 2}; //Columns 0 to 3

Как они получают количество {9, 8, 7, 6} а также {5, 4, 3, 2}, Вот полный код:

/*4x4 Matrix Keypad connected to Arduino
This code prints the key pressed on the keypad to the serial port*/
#include <Keypad.h>
const byte numRows= 4; //number of rows on the keypad
const byte numCols= 4; //number of columns on the keypad

//keymap defines the key pressed according to the row and columns just as appears on the keypad
char keymap[numRows][numCols]= {
{'1', '2', '3', 'A'},
{'4', '5', '6', 'B'},
{'7', '8', '9', 'C'},
{'*', '0', '#', 'D'}
};

//Code that shows the the keypad connections to the arduino terminals
byte rowPins[numRows] = {9, 8, 7, 6}; //Rows 0 to 3
byte colPins[numCols]= {5, 4, 3, 2}; //Columns 0 to 3

//initializes an instance of the Keypad class
Keypad myKeypad= Keypad(makeKeymap(keymap), rowPins, colPins, numRows, numCols);

void setup() {
Serial.begin(9600);
}
//If key is pressed, this key is stored in 'keypressed' variable
//If key is not equal to 'NO_KEY', then this key is printed out
//if count=17, then count is reset back to 0 (this means no key is pressed during the whole keypad scan process

void loop() {
char keypressed = myKeypad.getKey();
if (keypressed != NO_KEY) {
Serial.print(keypressed);
}
}