0-5V signal output to start 230V DC circuit
I assume you will be activating a normally open relay to switch the 230VAC, and these relay will be activated by a 24VDC signal. Somehow you need to amplify the TTL level signal from your parallel port to the 24VDC. I have often seen in CNC machines large relays for the mains power that are activated by smaller relays. You can probably drive such a smaller relay with a transistor and possibly a few resistors, depending upon the current requirements of the smaller relay.
I don't know what the current requirements are for the large relay, but https://www.ixysic.com/home/pdfs.nsf/www/LCA110.pdf/$file/LCA110.pdf is able to drive 200mA drawing only 2mA input. Do you know if that is sufficient?