Domotique Arduino Side

void setup() {
  Serial.begin(115200);
  for (byte i = 2; i <= 13; ++i)
    pinMode(i, OUTPUT);
  }

void loop() {
  if (Serial.available()) {
    byte cmd = Serial.read();
    switch (cmd) {
    case '1':
      Serial.println();
      for (byte i = 2; i <= 13; ++i){
        Serial.print(digitalRead(i));
        if (i != 13)
        Serial.write(';');
      }
      break;

    case '2':
      for (byte i = 0; i < 24; ++i) {
        Serial.println();
        Serial.print("BOOT");
      }

    case 'a'...'l': // GCC only (Not C standard)
      byte pin = cmd - 'a' + 2;
      if (digitalRead(pin) == LOW)
        digitalWrite(pin, HIGH);
      else
        digitalWrite(pin, LOW);
      break;
    }
  }
}