Garmin 530 TCAS
We have the Garmin 430/530 stackup with TCAS on the 530 which comes through the Garmin GTX 330 transponder. It's not actually called TCAS on that system, but Traffic Information Service (TIS). I'm not sure what the distinction is. Anyway, it works great. The TIS displays up to 8 responding aircraft within 7nm horizontally within a block of airspace 3,000 ft below to 3,500 ft above your aircraft. It gives a projected flight track of the aircraft and a trend, up or down. There are limitations. The system only picks up aircraft that are responding to ATC TIS radar sites and/or have a transponder onboard and operating. If the target aircraft is too low or does not have a transponder, it's invisible to the TIS. The Garmin 430/530 can also accept weather datalink info and Terrain Avoidance info as well. The whole setup is expensive, but one of the best packages that I've seen.