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Converting a GTX-327 from Parallel to Serial Altitude Encoding

Posted: Mon Mar 15, 2021 12:50 pm
by christoph.glomski
Hello,

I decided to join the 21st Century and change the altitude encoding inputs to my Garmin GTX-327 transponder from parallel to serial, driven by my Efis Xtreme. So far so good. Garmin supports the serial input, now i have to connect it now. At first, does somebody has experience with this issue? I found a description for Dydnon D-6, there are some differences with wiring, but finally it works.

After i readed the manual of the MGL Efis, i have question regirding the data output. In the altitude setup i can switch on / of the serial output. But witch port / should i connect to Garmin? Is it Pin 5 (RS232 Port 2 Transmit), or Pin 7 (RS232 Port 1 Transmit)? Wchich of them is sending the altitude signal?

Greetings
Krzysztof

Re: Converting a GTX-327 from Parallel to Serial Altitude Encoding

Posted: Wed Mar 17, 2021 4:37 am
by hpmicrowave
Did you get your question answered? If not ill send you my GTX-327 wiring diagram!

Cecil

Re: Converting a GTX-327 from Parallel to Serial Altitude Encoding

Posted: Wed Mar 17, 2021 7:24 am
by christoph.glomski
Hi, I just see that my question may have been misunderstood. I have the operating instructions for the GTX 327. I have to feed pin 19 with serial altitude data.

Now the question is which of the two outputs on the Xtreme Efis delivers me the altitude data. Is that pin 7 or pin 5. I can do the rest.
Many greetings

Re: Converting a GTX-327 from Parallel to Serial Altitude Encoding

Posted: Fri Mar 19, 2021 9:08 am
by christoph.glomski
Ok i was sloppy with reading the manual. It is described in deatil: "SERIAL OUTPUT: Select “ON” to enable the RS232 serial altitude output. This formatted serial RS232 message can be directly interfaced to various RS232 serial input transponders. If a parallel Gillham output is required then a CNV-ALT2 can be purchased from your MGL Avionics distributor to convert the RS232 output to a parallel Gillham output. The RS232 is output on PIN 7 (RS232 port 1 TXD).

Sorry
Christoph