IBM RT PC, Options Installation, Page: 187 / 254

Section 6. Communication and Network Adapter Options 6-39
Interrupt Level Switches
Use the following diagram to set the interrupt level on IBM 8-port
adapters; use an opened paper clip or a ball-point pen to set the
switches.
Note:
Set all 8-port adapters to the same interrupt level to ensure
optimum performance. When used together, 4-port and 8-port
adapters must be set to different interrupt levels.
Adapters installed in the RT PC must be set to different interrupt
levels from those installed in the IBM 6192 Expansion Unit.