How do I set up serial communication between two Holybro Telemetry Radios?
I faced the exact same problem as I am working with a HolyBro V3. It gave me a headache for a while...
Finally, I figured it out that the Baudrate must be set to &quot;57600&quot; as it is the default baudrate for HolyBro chipset. Bingo was his namo!
If you want to change the baudrate, you have to somehow update the HolyBro firmware.
Here is my code for Receiver:
# Receiver
import serial

ser = serial.Serial(port='/dev/ttyUSB0',baudrate=57600,timeout=1)
while True:
    b = ser.read(50)
    print(b.decode())

and the Transmitter:
import serial
import time

ser = serial.Serial(port='/dev/ttyUSB2',baudrate=57600)
while True:
    ser.write(b'Hi There!')
    time.sleep(2.0)

Remember to set your serial port per your setup.