Good Morning Gentlemen,
I'm hoping that the description of this problem proves more difficult that the solution. Any help will be very much appreciated.
2 systems set up in different aircraft and configured exactly the same way except for the Hex ID and Reg-ID.
Hardware: Pilot Aware, Farnell Cable, Funke TRT800
Software: August 2016
The transponders in both systems are getting GPS data as evidenced by accurate position report in transponder setup screen.
System 1:
Can see itself on its "traffic" screen as C,S,A and P in mode column with SIL 0 and SILs 0. There is nothing in the final column (aircraft and owner)
Can be seen on system 2 as C,S,A etc etc
In summary system 1 appears to function properly
One strange thing has been the occasional appearance of system 2 Reg on system 1 traffic screen EVEN WHEN SYSTEM TWO IS ENTIRELY SHUT DOWN. We presume that at some stage during testing we have put system 2 reg into system one (why would we do that?

) and this is now cached. Can't remember doing this however.
System 2:
Cannot see itself on its "traffic" screen at all
Can be seen on system 1 traffic report as a PA, but no C,S or A. In the last column of the traffic report a full description of the aircraft and the fact it is privately owned is given.
Our first thought was that system 2 transponder may not be emitting but:
The Mode S can be seen by B'ham ATC (haven't asked them about ADS B since fitment not yet approved)
Both Mode S and ADS B can be seen on a POWER FLARM both close to and 1/2 mile from the Aircraft. On the face of it therefore the System 2 transponder is working.
We are considering a software reload onto the SD cards of both systems but wonder if there's anything else to consider.
Thanks
David