From the in-estimable Chad Micheal:
Follow up to this weekends phone call…..
The L3 NXT transponders are DO-181E compliant. Which means they do not accept “All Call” transmission on the ground. The aircraft has to be weight off wheels for”All Call” to work.
If atc at an airport wants to see the aircraft on ground or if a tech wants to check ground transmission with an IFR6000, they must ping the hex code for the aircraft to receive a reply.
In order to do a ground check using the IFR6000 box, you must configure the hex code in the settings block.
So take that!