I'd previously built a parallel port for the Ace on veroboard from TTL logic, based on a design a friend of mine came up with for his ZX Spectrum, so I could use the Ace to ride around on a micromouse. To drive the ASR-33, I had a 24v smoothed power supply that I'd scavenged from a skip when my mother's employer had scrapped some prototype ATMs (cash dispensers), so I wired that up to give +/- 12V and switched that from one line on the parallel board using some power transistors desoldered from the ATM. Then I wrote code to bit-bang 110baud RS232 in Forth on the Ace. It took a lot of trial and error, as there wasn't exactly a lot of documentation available in the town library, but I got there in the end.
I'm not sure if I was the only person who ever had a printer connected to a Jupiter Ace, but I'm pretty sure I was the only person to print Ace code listings to an ASR-33. I wish I still had that ASR-33 but somewhere along the way my parents decided they were fed up with storing all my junk, asked what I wanted saving, and I didn't think to save that.