> The 4500 doesn't seem to have a SCSI-Controller so what for is the
> SCSI-Cabeling ? How to use it with the 4500 ?

  The BA400 chassis was redesigned to allow piping SCSI up into the
backplane for the configurations that included a TZ* tape drive in
the right-hand bay (instead of the default TK70, or a TF* drive).

  The idea is that a KZQSA board would be installed in one of the Q-
bus slots and a double-right-angle SCSI cable would connect it to the
connector you found.

> And what about the small Slot between the two right Drive-bays ?
> There's only one small PCB (PCC1V0) plugged into the slots
> backplane-connector . What's that for ?

  If it's between the (fatter) tape bay and the disk bay, it's probably
to select/terminate the SCSI bus rather than the DSSI bus for the tape
drive. But I'd have to open up a system to be sure.

Terry Kennedy <terry@tmk.com> http://www.tmk.com