====== Debian Linux: Enable a Serial Console ======

Edit service:
<code>nano /etc/systemd/system/getty.target.wants/serial-getty@ttyS0.service</code>

Find the line starting with ExecStart, make a copy and comment it out (as a backup / retreat path), then edit the active line. Remove --keep-baud and perhaps also leave just your one desired baud rate = reduce the comma-separated list to a single item. Like this:

<code>#ExecStart=-/sbin/agetty -o '-p -- \\u' --keep-baud 115200,57600,19200,9600 %I $TERM
ExecStart=-/sbin/agetty -o '-p -- \\u' 115200 %I $TERM</code>


Note: you have hereby edited a systemd unit file. You will need to tell the systemd superdaemon to reload it. (If you forget to do this, systemctl will suggest you to do it.)
<code>systemctl daemon-reload</code>

Time to start the already altered service unit:

<code>systemctl start serial-getty@ttyS0
systemctl status serial-getty@ttyS0</code>

To test if it works, use your favourite terminal emulator. An example how to start minicom:

<code>minicom -b 115200 -D /dev/ttyS0</code>

 To enable screen while system is loading, need to enable it in GRUB bootloader:

<code>nano /etc/default/grub</code>

Edit or append lines:
<code>GRUB_CMDLINE_LINUX='console=tty0 console=ttyS0,115200n8'
GRUB_TERMINAL=serial
GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"</code>{{:screenshot_2024-11-04_14-52-34.jpg?400|}}


 Then update Grub
<code>update-grub</code>


 ====== Connect ======

 When connecting from another Linux, can use minicom
<code>apt install minicom</code>

Detect connection 
<code>ls /dev/tty*</code>

For example, /dev/ttyUSB0

Then connect to remote PC
<code>minicom -b 115200 -D /dev/ttyUSB0</code>


== P.s ==

I prefer to use byobu as failsafe if have problems to exit minicom

<code>apt install byobu</code>

Sources:

[[https://www.reddit.com/r/linuxquestions/comments/s6m11l/how_to_enable_serial_with_debian_11/|Reddit]]

[[https://www.cyberciti.biz/faq/howto-setup-serial-console-on-debian-linux/|cyberciti.biz]]