I'm about a week late with this update ...
I purchased another IBM PC Compact printer from eBay to have another spare. For those of you who are not familiar with it, it is a small serial printer running at 1200 bps that prints on fax paper. The print quality is atrocious but it never needs ribbons, so that is a plus. Originally designed for use with the PCjr, these could be used on PCs with an adapter cable. They were also often found on C64s after IBM dumped a load of them onto the secondary market.
These printers are not all bad. Here is a sample of a JPG that I printed on it:

This particular printer had a D shell 25 pin male connector on it wired as DTE (Data Terminal Equipment) which is wrong for interfacing with a computer. The original PCjr connector had been hacked off and crudely replaced. I corrected the gender and the wiring so now it has a D shell 25 pin female connector wired as DCE (Data Communications Equipment). I used an RS232 breakout box to do the debugging, which I found to be mesmerizing to watch while it prints. If you want to enjoy the blinky lights there is a video linked the page where I describe the printer.
That led to some fun with an oscilloscope trying to find bits on the wire. It was a little tricky with a 20 year old analog oscilloscope with no buffering, but I was able to clearly capture three full bytes at 4800 bps and decode by hand just by looking at the voltages on the scope.

("SOS" at 4800 bps, no parity, 8 data bits, one stop bit on an analog oscilloscope.)
It was a good day ...