usart A13 <->PC

[anra]

Hi
I am using a usart communication between my computer and A13 using a usb-serial converter (cable F). When I send a message from A13 to my computer it works correctly. Ex:

In a A13 terminal: stty -F /dev/ttyS0 9600 and echo "hello" > /dev/ttyS0 I can send hello to my Pc. I read correctly hello.

On the other hand I send "helloPC\n" from my Pc to A13. I use  cat /dev/ttyS0  to get the helloPC but I got nothing. Only a line return. And then the cat /dev/ttyS0 stay blocked: If I send other helloPC there is not other line return.

If I connect the TX of the A13 with the RX of the A13 I can read correctly what I send. Does anyone what is the problem reading what is coming from the PC? thanks