:lol: Found'em! It turns out that my three different IIsi NICs are actually three different revs of the Asante MacCon NIC! :

The most recently acquired one had a Math CoPro in the socket and a 10bT connector in between the Thin-n-ThickNet Connectors, so that's the one I grabbed.

Testing done for powerup/boot: NoPro.

Testing with (known good) SuperMac Spectrum/8si v 1.0 PDS card installed yielded boot, but no video out of the PDS VidCard . . .

. . . which is the same result I got with the (each known good) Radius Color Pivot II IIsi Riser Card/Color Pivot II SE/30 Direct Slot combo . . .

. . . addressing conflict for sure . . .

. . . time to head to gamba to brush up on my MultiCard SE/30 Hacking Lore! }