Some dc5800 desktop PC were delivered with a paralell port as an option. Most were not.
Since yours does not have a paralell port, you will need is to install a low profile paralell port adapter. They are available in PCI and PCIe x1 versions.
There are examples on the following Google web search that I did.
https://www.google.nl/?ion=1&espv=2#q=parallel%20port%20adapter%20low%20profile