Hey there

YES it's a Dual Page Display card.

I own the same card but for the SE/30. It has the same 9 pin connector as well.

I checked the Mac Driver Museum. And I don't think the driver for this card is on it. It could be the DisplayServer II - DPD but I'm not sure.

Anyway here is the link A collection of 16 Lapis drivers

BUT maybe the driver is the same for both SE and SE/30 ? Who knows?

I can't start mine up (its PSU is off to Uni) but as soon as I get it back I'll make an archive of the CDEV and I'll put it on Mega so you could try it.

I hope it still works, since it was left in the woods for quite some time, I think it may need some new caps (Especially C31!)

It surely is a great find, and you have the Video cable as well as I can see from your other post!