New Group Value API is here. Using BinaryValue, you can easily read and write binary values (eg. Lights ON/OFF). Blink over KNX now looks really simple. No more hassles with telegrams 😃.

Short example follows (setup, includes etc. omitted).

BinaryValue binaryGroup001(0, 0, 1, &changeListener); // binary group 0/0/1 defined

void loop() {
  delay(5000);
  binaryGroup001.setValue(!binaryGroup001.getValue()); // toggle binary group 0/0/1
  bcu.loop();
}