"Bob Noel" wrote in message
...
In article Pe%vk.431$Dj1.271@trnddc02, "Mike"
wrote:

I'm not sure what "system" or "field" you're referring. The computers at
the centers and tracons have no idea if the transponder is ModeS or not.
They only process the beacon code and display the ACID that's in the
flight
plan.

The centers and tracons don't have Mode S radars yet?

The centers never have and never will other than a few terminal radars which
are piped into the centers for low level coverage in some areas. The ModeS
systems themselves are located all over the US, but there's no datalink
capability between the sensor and the automation system. So the only thing
forwarded to the TRACON from the transponder is the 4 digit octal beacon
code and the 3 digit altitude.