I'm seeking confirmation or correction. The GTX manual shows a bi-directional 232 connection to a GSU73, and an incoming 232 from a 650's 232 output. The notes say the output is the ADS-B GPS data. Is the bi-directional 232 the "control" connection for pilot manipulation of the GTX through the 370? A GDL39 is part of "paneling up" if that makes any difference. It's output connects to one of the 650's inputs, yes?
I ask because I get wrapped around the axle over the communications, generally because I don't kin which signals carry what information and have priority over other similar connections. E.g., ARINC trumps 232, but does the equipment know,or can it be made to know, that? 1,000 pages of manuals get a bit overwhelming.
John Siebold
Hello John,
Radomir and Brantel typed faster than I and helped you out, but I thought I would go ahead and post this anyway.
We try very hard to always show every wire needed between the G3X components and any other Garmin product to which G3X can be connected in the G3X Installation manual. Customers often think that that they need to refer to the transponder or other installation manual, but that is seldom the case.
To answer your first question, yes, the single bi-directional RS-232 connection shown on page D-3 of the Rev. G G3X Installation manual between GSU73 port 3 and GTX23ES port 1 is the only connection needed to have a fully functional transponder. Customers that have a VFR G3X aircraft without a GNS or GTN can even have a fully functional (but non 2020 compliant) 1090ES ADS-B Out solution that wakes up the ground stations and provides traffic and weather to their GDL39
with this single RS-232 interface to the GTX23ES.
You don't need either of those A429 transmitters on the transponder connected to the GSU73. These are only used if you want to send TIS-A traffic data to a GNS or GTN unit. The GSU73 provides pressure and GPS data, control data, and even receives TIS-A data over that single do-it-all RS-232 link.
Since you have a GTN, you will provide the 2020 compliant position data from any unused RS-232 output on the GTN (configured to ADS-B Out) to RS-232 Port 2 on the GTX23ES. As Radomir indicates, this is a single one-way connection between the GTN and the GTX23ES.
With regard to the GDL39, please follow the drawing on page D-12 to add a single bi-directional RS-232 connection from the GDL39 to either Port 1 or Port 2 (both options shown) on the GDU 37X MFD. Traffic received by the MFD will be shared with the PFD(s) enabling ADS-B traffic to be shown both on the MFD map and traffic page on on the PFD(s) in the synthetic vision presentation.
Please let us know if you have further questions.
Thanks,
Steve
