IBM 8239 Token-Ring Stackable Hub, Setup And User Manual

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6. Use the DISPLAY INVENTORY terminal interface command to verify that the
8239 recognizes the 16-Port Expansion Feature.
RI/RO Module
To install or remove a Ring In/Ring Out Module, follow the directions in this section.
Attention: You must power off the 8239 before installing or removing a Ring
In/Ring Out Module.
You do not need to remove the 8239 from a rack to remove or install a RI/RO
Module.
Figure 3-2. RI/RO Module
Removing a RI/RO Module
1. Remove power from the 8239 by unplugging the power cord.
2. If you intend to replace the RI/RO Module, label the cables attached to it. This
precaution will ensure that you reconnect the cables correctly.
3. Disconnect the cables from the RI/RO Module.
4. Loosen the two thumbscrews by turning them counterclockwise until the screws
are loose enough to remove the module from the 8239.
5. Pull the RI/RO Module along the grooves of the guide rail and remove it from
the 8239.
6. If you are not replacing the RI/RO Module immediately, install a slot cover and
provide power to the 8239.
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8239 Setup and User’s Guide