If this is like my S8000 (model 30 I think) system, then yse, 1/4"
cartridges, DC300s IIRC. I believe the format is 4 track QIC11.
--
I don't think they had more than one kind of cart controller.
Have you archived the tapes, or the eproms from your system?
I know it's pointless to ask, since you don't have any way to
copy them, but do you have the hardware manuals for any of the
cards in the system other than the CPU (which I have scanned
already)