I'm wondering what the difference is between the two and if a separate software card is required for each? I've got a few CICS' and Plus' I need to test but I cant get any of them to boot. I've got Compact Plus CS flash cards of every release from 1.0 to 7.0 but none of them seem to work. I plug in the KSU with a flash card installed and the phones just continuously blink the triangles next to the line keys. I've left them plugged in for an hour just to make sure. Not sure what I'm doing wrong, or if its an issue with the motherboard but any help is appreciated.