It's about as mechanical as it gets! Fortunately there's no lock or anything on my board at least. Protocol (if you can call it that) is very, very simple. It's basically raw parallel output from the photo-transistors with each key giving a unique 1/0 combination by blocking different light channels and triggering a strobe channel. Downside is that apart from CTRL/Shift keys it's 1kro.headphone_jack wrote: ↑30 May 2022, 22:37Whoa, that Viatron. How close did you ever get to figuring out the protocol? I've seen more than a few of those now and would love to see one in actual operation. From what I understand the keys are locked without power, like a Selectric. Did you ever manage to get them to unlock?
The board needs 120V input to power the bulbs. 5V seems to work fine for the photo-transistors but they were intended to run at -14V from what I can tell in the manuals. The indicator bulb needs around 14V to get reasonable brightness.
I got it working with a proof of concept converter but the KRO limitation really just makes it a show-piece.
