Frsky pass through protocol on serial 5

Hi all i have 8 cube’s with Frsky pass through on serial 5 all work fine
i bought 2 more this year for a project on the go
four the life of me i cant get to on theses cubes to work
they all have the same firmware on them same prams file on all of them
so i pulled a cube out of working plane and put in the plane that was not working with no other changes work as it should
so then i put the one thats not working in a plane that works and still not working
have they made any hardware updates on the serial 5 ?

this got me beat over a week trying to fix lol


Ok worked out why there is no power on the Sbus out power pin on both of them
any idea why ?
or is it powered of the servo rail ?


well i found out my answer off servo rail :roll_eyes:

Master Philip may be we need to open up Topic with only wiring diagrams :fu::fu::fu:

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Glad you found your issue!

I will note that as on the middle of this year, serial 5 will be being reassigned, after we move new users to CAN for GPS to free it up.


it was not an issue! just lack good info that was my downfall :fu:


anyway all working great

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HI everyone,

After several years with my Pixhawk 1 I’ve just moved top the new Pixhawk Cube Orange and I’d like to use Yaapu in my Taranis. I’ve already have a cable based on the MAX3232 RS-232 to TTL converter breakout board.

I was wondering how you finally connected it. I guess you’ve connected VCC to a servo rail + pin, but I’d like to double check because my carried board is the last one and these pins seems the same, but there is not COM5 label next to the SBUSo (it’s just not labeled). I guess it is still COM5 but… just in case.


Answering to mysefl. So, I’ve just used Telem2 and it works like a charm. Thanks

On a Cube Orange you should be able to use a configuration like this:

No need for any TTL/RS232 converter board, just requires a single resistor.

Telem5/Serial5 (or COM5 as you say) on the new carrier board is dedicated to the ADSB receiver I think, so it’s not available for external connection.
Regarding the Vcc and Servo rail +, you would never connect from a Vcc pin (or from the power brick) to the Servo rail. Only ever connect an external BEC to the servo rail + to power actual servos or other equipment that would likely be noisy or need it’s own supply.

That’s very interesting!!

I’ve already used successfully a converter board, but I’ll also try this approach. Many thanks @xfacta

have you tested it on serial 4 the only port that i can get to work one is serial 3 ( GPS port one ) with out converter board.

with converter board it works fine on any serial port

I havent tested on a Cube Orange yet, that should be coming soon. Any of the Telem/UART ports should work the same, except port 5 on the Cube Orange.

after many hours of testing it will only work on serial 3 GPS port 1 i got 4 orange cube 3 planes and one chopper and tested it only works on that port on the current Autopilot 4.05 i have tested it with 4.10 Dev as well

If you get the chance, see if that TX_PullDown option works without the external resistor.