I am pretty much certain that it's for an SE, having now taken one of mine apart for the first time. The slot is the right size, and the board would fit across the logic board and inside the case nicely.

Click to expand...

The SE/30 and IIsi have a 120 pin (40 pins X 3 rows) PDS connector. The SE used the 96 pin (32 pins X 3 rows) connector. So what you have there is either an SE PDS slot card or one truly bizarre NuBus card (why would you ever lay a NuBus card on its side?). Hmmmm, I think the LC PDS slot also used the 96 pin connector, but then the backplane connectors would be on the main card and not on a cabled daughter card.

BTW, the card you displayed next to it is an E-Machines Futura IISX, which you may have already known. The daughter cards available for it were a DSP card (to speed Photoshop type stuff) and an Ethernet card. They could not be used simultaneously. The ethernet daughter board has a bug in its driver which is incompatible with Open Transport and only works with Classic Networking. So I find it less than totally enchanting. I wish I knew enough programming to disassemble it and correct the bug...