Apple Workgroup Server 9150/120 - Manual (Page 47)

6 If you are installing a PDS card, remove the termination card from the PDS slot.
Remember that the processor-direct slot must always be occupied by either the
PDS termination card or a functional PDS expansion card. Be sure to keep the
termination card in a safe place so that you can replace it if you remove the
PDS expansion card.
7 Remove the card from its static-proof bag.
Hold the card by its edges to avoid touching the connector on the bottom of
the card.
Connector
Installing an expansion card 31