Sneaker is right about the external connector. Leave it set for "Auto", then it'll terminate if there's nothing outside, or (it will) leave termination OFF if you connect an external cable.
My Cyberstorm II with CyberSCSI would malfunction with the Auto settings. I had to manually set to OFF and then use active terminators. (If I unplug my external CD, I have to plug in an active block) I'm not sure what it's deal was, but it seemed unable to handle the Auto setting in my case. The error I was recieving was a "Phased Frame SCSI Error", if I remember correctly. (It was a LOOOONG time ago!)
