What are the Serial Ports Connected to?

So in the /etc/default/arducopter file you can set the telemetry options but I was hoping to find some more information because I am looking at forwarding Mavlink data from the GCS through a USB port on the Navio2 to a second raspberry pi.

In the options menus you have your TELEM# options like so:
TELEM1="-A udp:"

We set our radio to 115k baud rate and it seemed like the way to do this was to set our second telem as an “-A”
TELEM2="-A /dev/ttyAMA0" since I wanted to use the UART port on the Navio2 to connect our telemetry radio with. However now I want to have telemetry data received by the radio on TELEM2 to be sent to a USB port to be forwarded to a second raspberry pi.

This leads to my system not connecting to my GCS. So I have a question as to which Telemetry is what Serial# in the parameters list?

Is it based on the lettering? like:
“-A” is for Serial0,
“-B” Serial1
“-C” Serial2
“-D” Serial 3
“-E” Serial 4

In that case how would i set a Baud rate besides my default one for that option as it says that “-A” is 115k baud rate while “-C” is 57k

On another note, how would I then get this mavlink data forwarded out the USB port.
I noticed in Mission Planner I have a Serial_PASS1 and Serial_PASS2 option so if I set one serial port as the input from my radio module and the second as my USB port would that forward the telemetry data out that USB port?

Hi Brandon,

You need to use different flags for each individual TELEM parameters. -A flag is usually used for TCP or UPD connection. For your UART radio, you can choose -C or -D. Your path to the serial connection looks fine.

Yes, you got it right. If you need a more detailed reference, there’s a part of the guide describing the mapping between switches and ports.

Mission Planner needs a direct connection with the port. So, it will receive the data on a USB port in case there’s a connected telemetry device.


How would I go about setting a different baud rate for each serial port in the /etc/default/arducopter file without having to change it in the GCS?

Hi Brandon,

The baud rate on Navio2 is controlled by parameters in the GCS app. It won’t be possible to change it in the launching file.

Ah ok
Thank you.

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