GDL-90 Protocol

Hi Everybody,

I'm studying the data stream between a NavWorx and an AFS-4500 that's installed in my -7A. It looks to be GDL-90 ( http://www.faa.gov/nextgen/programs/adsb/wsa/media/GDL90_Public_ICD_RevA.PDF ). According to section 2.2.2, I'm not so see any Message IDs with the most significant bit set to 1.

What's throwing me off is that I am seeing Message IDs with the most signification bit set to 1. Below are three examples. Anybody know what these messages are or better yet have an updated GDL-90 protocol spec handy (I can't seem to find one on the interwebs)? The FAA's copy looks to be Revision A from circa 2007.

7e8301ff03e9a17e

7e8601010109babc1500a1b5ba001d02000038000000ffffffff01000000df07081e102d3300000000000000000000000809030000000000000000004000000003000000030001000200000000000000449c00000001006ec17e

7e8d4e0c0010a981b72b7975756b4203b8800928880800000000000000000000000003e000000060af7e

7e87000280ff000000004e373131565a0000a981b70300a8a07e

Thanks,
/\/elson

PS. Any spaces that may be inserted into the above hex strings are being done by the forum; they aren't in the original strings.

David,

How about a vendor-specific message outside of the specification? It seems likely that Navworx might throw a few of those in for diagnostics, device status reporting, etc.

David

Hi David,

I guess I could see that. Seems like a lot of bytes for diags, though. I managed to get some of the Stratux's ( http://www.vansairforce.com/community/showthread.php?t=128742 ) and dump978's code recompiled on X86. I then dumped out some included sample data to the console looking for '7e8...' data and didn't find any.

Anyway, thought I'd ask.

Thanks,
/\/elson