IIx and IIcx differences, IIcx has 3 less slots, no rom slot in the IIcx?,

SE/30, has no nubus, but a PDS slot, however its like a IIcx, then the IIsi, that has one slot that is NuBus or PDS, depending on the adaptor?

8-o

hard to keep track of all this.

the IIx,IIci,IIsi,SE/30 all have ROM slots, i'm not sure why they skipped the IIcx,