I'm continuing my thread here since it no longer concerns 7-segment display.

I've started looking for a small, affordable BCD coded rotary switch, and I'm wondering if anyone has any suggestions.  So far I think I've figured out that I need an 8 position, BCD (i.e. not grey) coded switch with adjustable stops.  The intended use is to control XPDR_Mode, which normally has 5 positions, which is why it is important for it to be adjustable.



May 8 in Input Controls by

1 Answer


All you need is these cheap 8-position switches ($0.8  for a piece):

Link to AliExpress (example)

Then, simply assign it for selected XPDR type and it will be functioning exactly in the order required by this transponder type (the mode order is automatically assigned by the plugin based on the selected transponder type).

So, from a users point of view, this switch works the same way as a simple rotary switch, just using only 3 inputs.
Doesn't matter that it has 8 positions - you use only the first 5 (0-4).
It has 4 pins  marked as 1,2,4,8.   You should connect the first 3 (1,2,4) in this order to the digital inputs, that's all.
("C" is the central pole, goes to the GND):


May 8 by


Fixed, please use the updated version 9.57c

Now, the plugin sets order correctly depending on the selected transponder type.


Hi Vlad,

Thanks for taking a look at it.  I tested this morning and the order looks correct, however position #2 on my switch doesn't select TEST mode.  I assigned XPDR_TEST to an LED (along with XPDR_ON, XPDR_STBY, and XPDR_ALT).  I was able to select TEST mode (out of sequence, of course) on 0.9.55c.


Oh...  I see,...  (we tested seems everything before uploading, but didn't noticed this)

It's the "GND" position, not test,
The plugin mess it with type 4  rotary switch.... (taking the GND from type4 and skipped GND in type4)..

OK, one more  small fix need to done.

Update 2:

Corrected, download again the same, but updated version 9.57c 


Thanks for the 2nd update, Vlad.  Works great!