Hi - welcome to the board.
Please know that this board is for users of Avolites products (lighting consoles). Only a very limited number of users - and many years ago - used this graphic tablet for their lighting console. But this is years ago.
However, here come some hints:
- originally the 1212 HR came with serial connection on a Sub-D 25 (which you call a parallel connector - but it isn't: it's just a 25pin connector which was used for both, serial and parallel data transfer - see
https://en.wikipedia.org/wiki/D-submini ... ions_ports: "RS-232 devices originally used the DB25, but for many applications the less common signals were omitted, allowing a DE-9 to be used.")
- later models of the 1212 didn't have the cable directly attached, but used an RJ-45 connector (which you call 'Ethernet' - but again, it is just a connector with 8 pins, commonly used for Ethernet, but suitable for many other uses, too), and came with a cable RJ-45 - DB-25
- that being said, I would think your tablet still has a standard serial interface, only lacks the connector you need for your Dad's computer
- there are adaptors for serial connections which interconnect between a DB25 and DE-9. Either you get the parts and try soldering one yourself, or you fetch such a ready-made adaptor somewhere (I fear I got rid of my last such adaptor many years ago). See
https://allpinouts.org/pinouts/cables/s ... in-serial/ for pinout, see
https://www.google.de/webhp?sourceid=ch ... r+DB25+de9 for complete adaptors.