Computer Testing
So printing a self test is good and all, but will the thing actually print from a computer? How do you even hook it up to a computer? Is it serial? Parallel? Let’s find out.
The printer itself had the typical vintage gray cabling with a DB25 male plug at the end. In reading the manual, I found out the interface was serial, and some settings are set by dip switches on the printer INTERFACE board. Since the plug was male when most serial ports are also male, I needed a gender changer, and for good measure also used a null-modem adapter.
Note: There are two “sets” of settings; some jumpers (jumper wires) on the main logic board, and dip switches on the “interface” board, which is the smaller of the 2 boards mounted on the door inside the stand. The jumpers on the larger board pertain to how the smaller board talks to IT, and then the dip switches on the smaller board define how IT talks to the computer, so if you’re following along, disregard the jumpers on the big board; they’re probably fine, just go by the dip switches instead.
In looking up the dip switches, I found that the printer was set for 2400 baud, xon/xoff flow control, and no parity. I ended up pulling out an old laptop with Windows 98 on it, and for fun, added a “generic/text” printer using those settings. (I admit I tried several different settings and variations before settling on this! It’s a printer after all!). I pointed it at the com port, set the baud, 8 bits, 1 stop bit, no parity, and xon/xoff flow control, and tried printing a simple text file to it. IT WORKED! I was amazed that a 42 year old printer printed fairly well for what it is.
Some time later I got it all back together, even found some decent stainless steel screws for the cover, and the printer was sold at #VCFEAST in Oct 2021, supposedly to be paired up with a DEC PDP/8.