Jetson UART connection to TELEM1 or TELEM2

Hi All,

I am facing an quite odd error.
I am using seeed studio A603 companion board, along with cubepilot orange plus. 
Both have connected with each other through Telem 2 on FC and uart connection on the companion. 
 
I am able to see heart beat from FC, but I am not able to send any commands to the FC.
 
With Ardupilot it is working, but with PX4 is it not working, i verified with latest version of PX4 and version 1.14 . 
 
It would be great if any could help me out here, I am clueless , why such behaviour is observed.