Can't use new monitor / odd screen

I was hoping perhaps someone here could help me. I recently was given
a nice 20 inch monitor by a guy who was going to a flatscreen, and didn't
have space in his apartment for the older monitor. He was running it on a
mac, with an adapter which had dip switches. The cable ended in RGB and the black sync wire.

After a little digging, I was able to buy a vga cord that had the four
outputs. However, I tried to connect it, and the monitor looks all
scrambled. I checked the inputs, and they're all set.

My computer is a P3-500, running with a Voodoo3-3000 card. There are no
distinguishing marks on the monitor to tell me who makes it, or what model #
it is. There's a serial #, 1894470020, with a small DM subscript
underneath, on the back. Digital Machines? The controls on the bottom of
the monitor are v-stat,h-stat,v-cent, brightness,contrast, power.

I'm hoping to find out what make/model this monitor is, and what the
refresh,resolution, and such should be. There's a utility where I can
change the refresh of my video card to a few seperate settings. It might only work for windows, but that's all I work in anyway...I can stand it garbling until windows boots. If I have to, I'll see about getting a Gemini card, but I'd rather not if I can avoid it.

I've included links to some quick pictures I took of the monitor, as well as
the adapter for the mac, in case that'd jog anyone memory. Thanks for your
help in advance. I was toying with the idea of getting an adapter that allows mac monitors to run on a VGA card, and just attatching it using the old macintosh cable and adapter, but I'd like to get it running with what I have now, if I can.

http://members.cox.net/ixijimixipictures/monitor/monitorfront.jpg
http://members.cox.net/ixijimixipictures/monitor/monitor bottom.jpg
http://members.cox.net/ixijimixipictures/monitor/monitorback.jpg
http://members.cox.net/ixijimixipictures/monitor/adapter.jpg

If anyone knows what model this monitor is, or has a solution, I'd appreciate it.