In article ,
Andrew Gideon wrote:

I understand that mode S transponders have unique identifiers, thus
eliminating the need for beacon "codes" as we use them today.

It *could* eliminate the need for beacon codes, but only if everyone
switched to Mode S transponders and all secondary radars were Mode S.


TIS travels via the mode S data link. TIS-B uses ADS-B's data link. So
no mode S transponder is required.

no mode S required for ADS-B (still required for other reasons - for example
a TCAS II system still requires Mode S)


So, in an ADS-B world, what's the story on transponders. Is mode C still
required? Does the ADS-B UAT replace a transponder? Something else?

The ADS-B UAT provides an alternate datalink in lieu of the Mode $ tran$ponder's
datalink.

The transponder is still required at this time. In theory, we could dump
transponders but that would require a change in how aircraft are located and
identified. Numerous issues have to be addressed (no pun), including
problems with spoofing.

--
Bob Noel
Looking for a sig the
lawyers will hate