RS485 using Serial.available() only scans one character

Projects Programming
4

Yes. That makes sense. How should the Slave know how much and when data is arriving?

I wrote a listener as soon as a Serial.available() is true

void loop() {

  // unsigned int incoming = rs485.scan(data);
  
  // if(incoming>0) {
  //   Logger::log(data,incoming);
  // }

  // delay(5);

  if(Serial.available()) {

    while(true) {

      byte r = Serial.read();
      if(r==120 || r==49 || r==50) {
        Serial.println(r);
      }
      
    }
  }

  delay(1000);

}

The while loop is constantly scanning the serial line. There should not be a timing issue, since I am constantly listening. Here also only '120' is detected.

Removing the if and constantly reading results in the output

120 // for the send character(s)
-1
-1
-1
...
120
-1
-1
...

but never '49' or '50'.

Shouldnt at least sometimes the other characters appear?