pH/ORP stamp using UART port

Hello,

I followed Paul's instructions using this little sketch, but when I run it I get always the same value in the Port Monitor: 16961
What's wrong ?

void setup() {
Serial.begin(9600);
}

void loop() {
char inData[24];
byte index = 0;
int ORP;
while (Serial.available() && index <24)
{
inData[index] = Serial.read();
index++;
inData[index] = '\0';
ORP = atoi(inData);
}
Serial.println(ORP);
delay(1000);
}

Many thanks,
Marian