Thomas Borchert wrote:
Gerry,


TIS is entirely Mode S based. It uses Mode S as a source to identify the
traffic near you and Mode S datalink service to uplink the data to your
aircraft.



Uhm, not quite, AFAIK. It does use Mode S datalink for the uplink, but all
traffic information is derived from center radar data.

None of the info is derived from the Center. Center doesn't have mode S
equipment. Only approach controls have mode S. A center may use an
approach controls mode S radar, that happens with Salt Lake and our
radar here at Billings.