Have you had any luck using a Wacom Artpad II serial tablet with an unpatched Ubuntu around 17.10? All the google results seem to be about obsolete software, or for more modern (Intuos-era) tablets.
A trivial execution of inputattach -w8001 /dev/ttyS0
does not produce a new input device, and I'm not certain that this is the right protocol for this device... nor whether the wacom_serial4.ko kernel driver even supports it.
If you have had success, please share your xorg.conf.d and any kernel and userland configuration you had to do.