IBM RT User's Setup Manual page 321

functions in the SCSI Adapter may be affected. See "Adapter
Conflicts" on page 1-19.
Switch Bank 1
AJZIF161
When 4-port and 8-port adapters are used together, each
Note:
type of adapter must be set to a different interrupt level.
Adapters installed in the RT PC should not be set to the same
interrupt level as those installed in the IBM 6192 Expansion Unit.
6-34 Options Installation