Why does cat < /dev/ttyS0 send output to ttyS0? [closed]

Question

When I use cat < /dev/ttyS0 and data is received, it doesn't display on the terminal that I typed the command into but instead gets sent back to to ttyS0 where it came from. How can I make it not do that?

Answer 1

It's not sent back but echoed, try

stty -echo </dev/ttyS0
cat </dev/ttyS0

and echo should be suppressed.