IBM RT PC Options Installation page 139

TNL SN20-9864 (May 1987) to 75X0217
• mM Monochrome Display and Printer Adapter not used
The first adapter jumper modules should be set to the primary
(Interrupt Level 4 for the serial jumper and Interrupt Level 7 for the
parallel jumper) position.
The second adapter jumper modules should be set to the alternate
positions (Interrupt Level 3 for the serial jumper and Interrupt Level
5 for the parallel jumper).
• IBM Monochrome Display and POOter Adapter used
6-6 Options Installation
With one IBM Personal Computer AT Serial/Parallel Adapter:
Set the jumper modules to the alternate position (Interrupt Level 3
for the serial jumper and Interrupt Level 5 for the parallel jumper).
With two IBM Personal Computer AT Serial/Parallel Adapters:
The first adapter jumper modules should be set to the alternate
positions (Interrupt Level 3 for the serial jumper and Interrupt Level
5 for the parallel jumper).
The second adapter jumper modules should be set to the primary
position (Interrupt Level 4 for the serial jumper and Interrupt Level
7 for the parallel jumper).
Note: The parallel port of the second serial/parallel adapter is not
used in this case. Ensure that the parallel port of the second adapter
is not activated by the AIX DEVICES command, or a conflict
will
exist on Interrupt Level 7.