# VOXL2 RC uart failure

Source: https://forum.modalai.com/topic/4068/voxl2-rc-uart-failure
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2025-01-08 03:24:55 UTC by tkddnjs825
Replies: 4 · Views: 919

## tkddnjs825 · 2025-01-08 03:24:55 UTC

We are currently using VOXL2 products.
I'm connecting voxl-elrs now, but elrs is not recognized.
I have several voxl2. When I connect elrs to another voxl2, it recognizes the connection. But the other one is not recognized. It seems to me that the elrs uart port is broken.
So I don't use GNSS so I want to connect els using that port.
Is there a way?

## Reply by Alex Kushleyev (ModalAI staff) · 2025-01-08 18:29:58 UTC

Hi @tkddnjs825 ,

Can you please provide more details:
- which ELRS receiver are you using?
- which connector / port are you connecting the receiver to?
- does the receiver appear to power on (LED on, etc) when you connect it to VOXL2 that is unable to communicate to it?
- does the same receiver work on another VOXL2?
- how exactly are you testing ability to communicate to ELRS receiver?

Alex

## Reply by tkddnjs825 · 2025-01-09 00:31:22 UTC (in reply to Alex Kushleyev)

Hi @Alex-Kushleyev ,
Q1. which ELRS receiver are you using?
A1. I am currently using BetaFPV Nano RX.

Q2. which connector / port are you connecting the receiver to?
A2. I'm using port J19 for VOXL2. It is connected to ports 1, 10, 11, and 12.

Q3. does the receiver appear to power on (LED on, etc) when you connect it to VOXL2 that is unable to communicate to it?
A3. The receiver is powered on because the LED is on and the controller binds the receiver to display the antenna.

Q4. does the same receiver work on another VOXL2?
A4. Yes.

Q5. how exactly are you testing ability to communicate to ELRS receiver?
A5. It's time to fly by connecting to another VOXL, and it comes out exactly when you scan voxl-elrs --scan, but in the problem voxl2, when you scan voxl-elrs --scan, ERROR comes out.

## Reply by Alex Kushleyev (ModalAI staff) · 2025-01-13 21:04:44 UTC (in reply to tkddnjs825)

@tkddnjs825 ,

The voxl-elrs utility only works if px4 is not running. Can you please confirm that it's not running on the voxl2 board where `voxl-elrs` is not working?

I will also forward this question to my colleagues who should have more info.

Alex

## Reply by Maxwell Schaefer (ModalAI staff) · 2025-01-13 21:30:46 UTC (in reply to tkddnjs825)

Hi @tkddnjs825,

In addition to Alex's question above, could you also please share which version of `voxl-elrs` is being used on each voxl2? The `voxl-version` command should list the versions of each installed package.

Can you also please confirm that in the voxl-px4 configuration file on the voxl2 that is not able to communicate with the ELRS receiver that the RC type is set to CRSF_RAW, like this: `RC=CRSF_RAW`.

Furthermore, if you could share the output of `voxl-elrs --scan` from the voxl which is unsuccessful that would be helpful.

Thanks,
Max