Mode S communicates to our ATC consoles through various commercial VHF or satellite datalinks. Updating us regularly (can be set at various times, practically 5-30 minutes) on the current and projected position of the aircraft. We trust such information on our screens a little more than the spoken word, and can use marginally less restrictive separation standards than full procedural control.
ADS/B sends the position information (without the projection) through the transponder signal direct to recievers maintained by your ANSP. The update rate is measured in seconds rather than minutes, the plan is that it will be equivalent to radar, and radar separation standards will apply.
http://www.airservicesaustralia.com/...sb/default.asp
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