ShoreGuy,
6.04->7.0 should be a software update. According to the following FAA document, it can even be done in the field:
http://www.faa.gov/AVR/AFS/FSAW/FSW0102A.DOC
The document above also shows the difference in callouts. Another way to tell software version is if you get a "traffic" TA between FL 310 and 420. Version 6.04 will give you one, 7.0 will not (RVSM).
TCAS I = TA only
TCAS II = TA/RA
TCAS III = TCAS II with azimuth advisories
Regarding TCAS III, it is not yet implemented. TCAS II only gives pitch advisory/resolutions, whereas TCAS III also can give azimuth (turning) advisories.
ADS-B and GPS-squitter are some of the terms used in the development of a system, where a GPS is added to the collosion avoidance system. This will allow especially smaller aircraft to "participate" in TCAS, as it is a lot cheaper, more precise and less space and weight consuming.
The major problem here is agreeing on a standard, because as usually there is a faster and cheaper way, and then there is a more expensive and slower path to follow, but the latter being more capable.
Read more about ADS-B, TCAS and GPS squitter implementation:
http://www.faa.gov/and/and300/datalink/navsur/gps.htm
http://www.faa.gov/and/and300/datalink/navsur/cdti1.htm
http://web.mit.edu/6.933/www/Fall200...ouilhet2a.html
http://web.mit.edu/6.933/www/Fall2000/mode-s/links.html
http://www.honeywelltcas.com/faq/whi...ointpaper.html
TCAS history/background:
http://www.caasd.org/proj/tcas/
Most important,
I would still say we should take it very serious as to find out whether certain screwd individuals are setting up transponders on the ground and faking the mode charley to reply with FLXXX returns, so any aircraft crossing that FL will get a TA or RA - which ATC will not see.