I have finish building the electronics for the GCU-478 from FSD. I have been able to program MobiFlight to perform all of the 478 functions in MSFS. Including the XPDR mode. Press the XPDR button and the duel encoder changes the code. Press the duel encoder and it sets VFR code. Press and hold the XPNDR button for .5 seconds to set IDT on. Press and hold the XPDR button for 1.5 seconds sets distress code 7700. Also press and hold the swap button sets COM1 active freq to 127.1. Using the keypad to enter a long flight plan is so much easier with the GCU. This one is in the default Cessna 172. I also use in in the G 36. The COM, FMS, and NAV functions all perform there designed functions when selected. I have posted the MobiFlight files on the FlightSimDIY Discord. All the hardware needed to build a GCU-478 are also available at simforyou.etsy.com. A 478 kit is only $75 for all the electronic parts needed. If you have a 3D printer you can get the stl files to print your own case
Didn’t know what that was till I googled it. I wasn’t aware that the default Cessna 172 had one of these. Can’t wait to see your finished product.
It doesn’t have one in the sim.
But I added it to mine because I do a lot of long distance flight plans (700 to 1000 miles) and I use a lot of victor airways and waypoints. Sooo much easier entering things via a keypad instead of using the FMS knob. It’s in the picture on the right. I also have a GCU-478 full functional in MSFS
Might be the wrong place to say this but. I also have them fully functional in X-Plane.