Noob question

Looking at the decoded data flowing by, I see the word CrossLink quite a bit..
Can someone give me a short (and simple) explanation of what data is being crosslinked and what is the path??

It might be TIS-B??

What is TIS-B?

Traffic Information Services-Broadcast, or TIS-B, is a component of the ADS-B technology that provides free traffic reporting services to aircraft equipped with ADS-B Receivers. TIS-B allows non-ADS-B transponder equipped aircraft that are tracked by radar to have their location and track information broadcast to ADS-B equipped aircraft."

So, I assume the FAA has some ground stations with ADS-B transmitters around here.. Maybe at the local Radar sites? Or Airports?

If I lived within range of one of those ground stations, it seems like I could have non-ADS-B transponder equipped aircraft, showing up on my display..
Looking just like planes with ADS-B signals..?. Or, is that data send on a different freq?