Don't know European rules, but the Trig TT21 installation manual says
in Table 3.1 that the altitude is 35,000 feet.

-John

On Sep 12, 8:08 am, cernauta wrote:
The factory brochurehttp://www.trig-avionics.com/library/tt21brochure.pdf
indicates that this Class 2 Transponder complies with the European
rules for "flying below 15.000 ft". Was it certified for flying up to
35.000 ft in the US? Lucky guys...