Skoda octavia vrs new kenwood headunit and k line?

Hi all I have just fitted a kenwood double stereo, which is superb. Installed a aerial amplifier for headunit and I have been Reading about the k line thing. From what I gather it's a diagnostics thing for the original skoda symphony headunit. Would anyone be able to shed some light on what the k line is about? The wiring harness supplied with the kenwood doesn't have any wires for pins 1,2 and 3. Ross tech article showed that k line was pin 3 on black connector. As there is no wire on the harness supplied by kenwood I'm guessing all is fine, as I read somewhere u had to make sure nothing was connected to it, I,e by taking pin 3 out etc...

Many thanks Daniel