As far as I understand the ST, you need a special cable that is vired (reset signal I think) so the ST "knows" that is connected to a monitor that can show 640x400 in black and white. The SM124 for instance have the cable built ind for the factory.
Both the OSSC and the RetroTink 5X can show that resolution so I an looking for a cable with the correct adjustment. Preferably a scart cable since both the OSSC and the RetroTink can handle that.
If such a cable exits
