DOKK / manpages / debian 12 / xserver-xorg-input-synaptics / syndaemon.1.en
syndaemon(1) General Commands Manual syndaemon(1)

syndaemon - a program that monitors keyboard activity and disables the touchpad when the keyboard is being used.

syndaemon [-i idle-time] [-m poll-inverval] [-d] [-p pid-file] [-t] [-k] [-K] [-R]

Disabling the touchpad while typing avoids unwanted movements of the pointer that could lead to giving focus to the wrong window.

How many seconds to wait after the last key press before enabling the touchpad. (default is 2.0s).
How many milliseconds to wait between two polling intervals. If this value is too low, it will cause unnecessary wake-ups. If this value is too high, some key presses (press and release happen between two intervals) may not be noticed. This switch has no effect when running with -R. Default is 200ms.
Start as a daemon, ie in the background.
Create a pid file with the specified filename. A pid file will only be created if the program is started in daemon mode.
Only disable tapping and scrolling, not mouse movements, in response to keyboard activity.
Ignore modifier keys when monitoring keyboard activity.
Like -k but also ignore Modifier+Key combos.
Use the XRecord extension for detecting keyboard activity instead of polling the keyboard state.
-?
Show the help message.

Specifies the X server to contact.

If syndaemon exists with a return code other than 0, the error encountered is as below.

Invalid commandline argument.
The connection to the X sever could not be established or no touchpad device could be found.
The fork into daemon mode failed or the pid file could not be created.
XRECORD requested but not available or usable on the server.

It doesn't make much sense to connect to a remote X server, because the daemon will then monitor the remote server for keyboard activity, but will disable the touchpad on the local machine.

Peter Osterlund <petero2@telia.com>.

Xorg(1), synclient(1), synaptics(4)

xf86-input-synaptics 1.9.2 X Version 11