byte xonxoffstate = 0; // 1 means don't send data

void setup() {

Serial.begin(9600);

}

void loop() {

unsigned char udaj = Serial.read();
if(udaj == 0x13) {xonxoffstate = 1;}
if(udaj == 0x11) {xonxoffstate = 0;}
if(xonxoffstate == 1) {return;}
if(xonxoffstate == 0) {Serial.println("Sent some data!!!");}

Serial.println("This shouldn't appear if xoff");
delay(1000);
}