Most cards don't even use the clock signals. Anyway AEN is what you need to play with, it is going to make the card not respond to most cycles present on the bus. You cannot simply disconnect it though, it needs to be tied high on the card in question (floating pins do not assume a fixed state for the most part and will toggle to the tune of whatever is going on nearby).

Thank you for the fast response!

It sounds like the AEN pin is the signal of interest. If I understand you correctly, I should disconnect from the ISA bus, and pull high (+5V) on the card.

-Brian

Yup, exactly.

As far as I remember, you need to decode AEN only for I/O cycles (to prevent false decodings during DMA), but AEN decoding is not needed for memory cycles. So disconnecting AEN is fine for disabling cards that only use I/O, but will not work properly on cards with ROM extensions (SCSI cards with BIOS) or shared memory (graphics cards, some high-performance network cards). Furthermore, disabling ALE does not change whether the device drives IRQ or DRQ lines, so it won't solve conflicts on these lines. Remember that IRQ lines should be driven by a totem-pole drive if the IRQ is enabled, and disconnecting AEN does not disable the totem-pole driver if it had been enabled while AEN was connected. A typical example for a card that has a totem-pole driver that can be enabled/disabled under software control is the standard IBM serial port.