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Connecting my Windows PC to a Linux system (Wheezy) via the serial port (RS232) basically works except one problem when sending a message from the the PC terminal the Linux system.

The reception of that message can be observed on the linux system using

cat /dev/ttyO1

But then that same message is echoed back to the PC terminal. I've verified that this is not due to some setting of the terminal. Also when the cat is aborted the messages are not echoed back any more.

Could anyone give an explanation and tell me how to stop the Linux system from relaying received messages?

I found a solution to this by disabling the echo:

stty -F /dev/ttyO1 -echo
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If you do cat < /dev/tty01 > /dev/null, do you have the same problem? –  lgeorget Apr 11 '14 at 10:43

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