How to send a sequence of AT commands to a serial port in bash?

linux bash serial-port at-command
Alex picture Alex · Feb 14, 2013 · Viewed 26.1k times · Source

In Linux I need to send a sequence of AT commands to a serial port on e.g. /dev/ttyS0, which has to wait for an OK answer before the next command is sent. I could imagine doing something like

echo 'AT' > /dev/ttyS0
echo 'ATS0=0' > dev/ttyS0
...

but this does not evaluate the answer from the device on that port.

Is there a very simple way to automate this within a bash script, probably with the help of socat and/or microcom but no tools which cannot found on the most simple linux system.

Answer

Keith picture Keith · Feb 14, 2013

If you install the PPP package you can use the chat program that comes with it. Or you can use kermit. Or the cu program that comes with uucp. But to do it with pure shell is trickier. You might be able to use the read and printf functions, with stdio redirected to the port.

some snippet:

stty -F /dev/ttyS0 38400 raw
chat -f script.txt < /dev/ttyS0 > /dev/ttyS0

Should get you started.

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