Interesting.

reading it without clicking the links, I was already suspecting the pinout to be for an M24, which has something like CGA output if i recall correctly.

Can you share some more details on the monitor you have, if any are available?
Worst case, i think, opening up the monitor and figuring out the pinout of the connector from where all the wires end up.

edit: nevermind. I don't know what to do with the SR and SB.

Highlight should correspond to Intensity and it appears that since there are no other intensity inputs, the monitor cannot show full 64 colors of EGA in the high resolution mode...

Tiido wrote on Yesterday, 21:31:

Highlight should correspond to Intensity and it appears that since there are no other intensity inputs, the monitor cannot show full 64 colors of EGA in the high resolution mode...

Correct. The manual states 16 color in 640x350. I'd assume that means 16 colors at the same time out of a palette of 64, that matches the specifications of the Olivetti with the Display Enhancement Board (DEB) installed which the monitor is designed to run with.

I btw found the pinouts in an old usenet post here: https://groups.google.com/g/comp.sys.att/c/x6 … /m/77DQS7kOHUIJ

Subject: Pinout for Taxan 9 pin Bob Eberly / George Wilkin to 25 pin AT&T cable […]
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Subject: Pinout for Taxan 9 pin Bob Eberly / George Wilkin
to 25 pin AT&T cable

How to make a cable to connect the 318 to the TAXAN or STB Card.

The connections for a 318 to these cards should follow this example which
is for a TAXAN 557 Gold Card. (The Paradise Card will NOT work with the
318 monitor.

The pinouts to connect the AT&T 318 monitor with the 25 pin connector to
a Taxan Gold Card (9 pin) are as follows:

25 9 Lead
PIN PIN Designation

1 8 H. Sync
2 1 SG
3 9 V. Sync
4 3 Red
5 4 Green
6 5 Blue
7 6 Intensity
8 7 NC
9 - NC
10 - NC
11 - NC
12 - NC
13 - Degauss
14 2 SG
15 2 SG
16 2 SG
17 2 SG
18 2 SG
19 2 SG
20 - NC
21 - NC
22 - NC
23 - NC
24 - NC
25 - NC

SG = Signal Ground
NC = No Connection

vetz wrote on Yesterday, 21:44:

I'd assume that means 16 colors at the same time out of a palette of 64

With only 4 digital signal lines it could only support a fixed palette of 16 colors rather than a custom palette.

DEB does temporal dithering on the 4 RGBI TTL pixels from the internal LUT dictated by the palette choice.
It is the same principle as EGA cards outputting to MDA monitors, just used in colour scenario.

Likewise, M19 uses same approach to achieve a fixed 16-shade CGA palette on its MDA-standard monitor in M24 640x400 compatible programming.

The DEB itself is 4 bit output so a normal RGBI monitor is fine, the card will do its magic in showing more than 16 colours on it (could flicker tho)

Ah, a personal holy grail that I have been seeking for decades as well! 😄

A number of years back, I acquired an ATI EGA Wonder 800 (non-plus) card for the exact same reason. Like the STB Multires, it supports Olivetti M24 (and M28?) 25kHz ("400 line" ) monitors.

According to the manual of the EGA Wonder (which as far as I understand also applies to the EGA Wonder 800 non-plus), it actually supports the different EGA palettes beyond the standard 16-color CGA palette, and it apparently uses pulse-width modulation (PWM) techniques to accomplish this. @zb10948, is this the same as the temporal dithering technique you mentioned? I believe so, because indeed, it's the same technique that some EGA cards (including the EGA Wonder) use to show 16 shades of grey on MDA monitors.

In addition to that, it also supports the Hercules monochrome graphics mode on these monitors.

And to top all of that off, the EGA Wonder even supports a non-standard higher 752x410 resolution mode on these 25kHz Olivetti monitors. Drivers for this mode exist for Windows, GEM and AutoCAD.

I'm not sure if the STB Multires supports a similar higher resolution mode.

Years before that, long before I even got a suitable card for it, and before the internet had become common, we had even soldered a 9-pin/25-pin adapter based on a pin-out that we got from someone. But I never came around to trying all of this out.

And the PSU of my Dad's M24 stopped working a few years ago, so I haven't been able to test it on that machine. I've always wanted to see how 16-color graphics (especially high-resolution 16-color graphics!) would look on the monitor that came with that M24. The M24's built-in graphics adapter never took full advantage of the monitor's true capabilities, and that was something that always frustrated me as a kid.

I guess I could try the monitor with the EGA Wonder card in another computer, but the monitor hasn't been turned on in years. We have preserved it, but I hope it will turn on without any black smoke if we try it. 🤞🏼

This was actually one piece of the puzzle for getting EGA to work in the M24. Apparently we were lucky to have the newer revision of the M24 that allows the on-board graphics to be switched off with a jumper setting. It also requires a BIOS update to fix EGA compatibility, but I managed to obtain the BIOS chips for those.

I should probably verify with a multimeter if the wiring of that that soldered adapter is correct.

This is really a project that I'd like to finally complete. I really should get that PSU fixed. Likely a matter of replacing caps. Not something that I have experience with. Maybe I should just replace and bypass the original PSU. It's an older PSU, and quite noisy.

Happy to continue sharing more knowledge and experiences on this topic here.