Here you go:
http://olivettim24.hadesnet.org/docs/video_pinout.pdf

Note: it's pretty proprietary, not used in other systems (other than AT&T 6300 which was just M24 in other case - even the later Olivetti M240 uses a 'normal' EGA card and monitor), you can find a description of its operation here:
http://olivettim24.hadesnet.org/docs/Theoryof … %22Fit%22%7D%5D

But good news: it uses analog output which means you can convert it to DB15 ("VGA"):
http://olivettim24.hadesnet.org/docs/video_converter.pdf

Thanks for the links, my idea was to use it connected to an EGA card

So I wanted to make a DB25 -> DB9 + power adapter

The DB25 to DB9 adapter works, I was able to get it to work but only with a video card that has an output at 31.5Khz, 70Hz (MCGA ?)

Getting the Olivetti M24 monitor working with an EGA card has been a long-term project of mine as well!

This monitor actually expects a 25 kHz signal, which some EGA cards support with a jumper setting, notably the STB Multires and the EGA Wonder 800 (although not the 800 Plus, AFAIK).

By the way, it's crazy how you got it working with a VGA signal too! 🤣 How did you manage the analog/digital conversion for the color signals, since the Olivetti monitor is a TTL monitor? Or is that not necessary when you're just sending it a monochrome signal?

By the way, there is also a color monitor for the Olivetti M24, which has the same DB25 connector. One notable difference is that the monochrome monitor is also powered by that same connector, whereas the color monitor has a separate 230V cable and uses the DB25 connector only for the video signal.

Not having many technical references on the monitor and above on the cards in my possession I simply created a DB9 to DB25 cable and tried several video cards with DB9 output, then playing with the trimmers inside the monitor. In the end with a card with the frequencies 31.5Khz, 70Hz worked fine. with other cards you could see half the screen or nothing.