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SoG Compatibility List

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SoG_Data_Excel5.sit (75.46 KB)
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[www].se [ftp].se [mirror].us [mirror].de (74.59 KB)
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[www].se [ftp].se [mirror].us [mirror].de (849.57 KB)
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[www].se [ftp].se [mirror].us [mirror].de
Guides on emulating older applications

This is not an app.
Still this info may be useful for classic Macintosh users looking for a replacement LCD monitor.
There are three obstacles when connecting, e.g. a Centris with a non Apple display.

PC displays will only have a 15/3 VGA connector.
An Apple DB15 to VGA adapter with DIP switches is needed.

Macs do have uncommon screen resolutions for PC monitors.
Make sure that both Mac and PC monitor do support a 640x480 resolution or better.

Old Macs video output has the sync signals on the same pin as used for Green in RGB.
Some PC display devices do support sync on green (SoG), many don´t.

The DL files are SoG compatibility listings from the PlayStation 2 Linux community.
If you can add a display working with SoG, please feel free to do so there -
and also in the short list below.

Monitors working with Mac SoG not listed in the above DL:

Fujitsu L 3190T (working with my iMac Bondi blue, 1024x768, black stripes at the sides)
Samtron 73V (as stated in manual)
Seiko (SII) CM1445 (working well with IIsi & LC)
SyncMaster A650 (as stated in manual)
SyncMaster 710TM / 910TM / 713BM / 913TM (SoG compatibility stated in manual)
SyncMaster 940NW (SoG compatibility stated in manual)
SyncMaster 943BM (see pictures)



lilliputian's picture
by lilliputian - 2019, December 16 - 10:03am

A dipswitch converter is not absolutely required for connecting an old Mac to a VGA monitor. I have not tried one, so maybe it will have more flexibility in terms of configuration, but the adapter below is what I've been using with my PB540c and LCIII connected to an LG Flatron (E2242T) and a small Philips LCD TV (19PFL3504D/F7) with great success:

All that said, this is technically about "Sync-on-green" monitors, and I don't have the expertise to know if this is applicable or not, or if one or the other is preferable.

24bit's picture
by 24bit - 2019, December 15 - 3:55pm

I did not expect finding only old Samsung SyncMasters to be listed here.
Maybe they were quite common, documentation is still available, which helps of course.

soudesune's picture
by soudesune - 2019, December 9 - 9:31pm

Mine was shamelessly copied too. It doesn't seem to be as informative now as it was when I first copied it though.

24bit's picture
by 24bit - 2019, December 8 - 5:01pm

Thanks soudesune!
Shamelessly copied together something.

Usually, there are 5 important signals coming out from a VGA card. The colors (Red, Green,Blue) and Sync (H-Sync and V-Sync). The voltage on the color signals is proportional at the brightness of the color at a given moment. The Sync signals are generally kept high, with short low pulses when retrace must occur.

Composite Sync (C-SYNC):
Some monitors support or need Composite Sync (C-Sync). C-Sync is both H-Sync and V-Sync pulses combined together with a simple circuit (dont try connecting the 2 wires together). The monitor can differentiate between H-Sync and V-Sync by looking at the pulse width. The V-Sync pulse is longer. Old sun monitors required C-Sync, for example.

Some monitors require the C-Sync pulses to be combined with the Green color signal.
In case you are wondering, the sync pulse does not interferate with the green signal because the pulses always occur at the end of a line or at the bottom of the screen.

soudesune's picture
by soudesune - 2019, December 7 - 9:39pm

SoG = Sync-on-Green: A composite horizontal and vertical signal sync for the green signal in RGB. Typically, monitors use 5 signals, one for red, green and blue, and one for each horizontal and vertical sync. Sync-on-green monitors utilize three connections, one for red, one for blue and two synced horizontal and vertical signals that are counted as one green video signal.