I would guess that any GPS that outputs RS232 sentences would work with a TT22.

6.1.9 GPS/TIS Line Speed
If a GPS input or TIS output has been configured, you should select the appropriate line speed using the rotary knob. Traffic displays using the Garmin protocol run at 9600 bps. Panel mount GPS units with Aviation format outputs generally also run at 9600 bps. NMEA GPS units generally run at 4800 bps. Freeflight 1201 and NexNav 3101 GPS receivers generally run at 19200 bps.

Of course only for Experimental.

Richard
www.craggyaero.com.