On first turning the machine on it would simply beep and display some odd glitches on the screen. After referring to the manual and simply resetting the DIP switches on the unit to correspond with the display that was attached it booted up.
The unit is currently booting from ROM, it can also be set to boot from floppy but I’ve yet to get the disk unit working, there’s also a 26 pin connector in the disk unit which I assume is some sort of proprietary HDD connection.
I’m having a fair amount of difficulty tracking down much information on the PX-16. From what I can tell it was mainly used in Europe and often by field service engineers. Its modular design allows you to swap out the keyboard and screen for alternative versions and like the PX-4 it has a removable cartridge on the right of the machine which can house various peripherals.