Drive PX2 uart communication

How can I use the UART adapter on the Drive PX2 AutoCruise harness to send simple messages from host to a simple app listening on the target?

I can see the /dev/ttyTHS1 and /dev/ttyTCU0 along with all /dev/ttyS

Is it possible to send a simple msg from my host’s /dev/ttyS0 to one of these devices?
I have tried to configure ttyS01 on the host via
stty -F /dev/ttyS0 cs8 -parenb -cstopb -echo speed 115200
and echo “test” > /dev/ttyS0
while the target app simply listens on one of the above devs?

Thanks in advance

Dear @hermann.fuerntratt,
How you are connecting host and target to establish connection(via debug cable?) and Can you clarify, you want to send message from host to target?

I can see the /dev/ttyTHS1 and /dev/ttyTCU0 along with all /dev/ttyS

is it on target?