HP 748 Owner's Manual page 54

NOTE:
5-2
PCI Card Installation
This chapter describes installing a PCI card in the Model 748 workstation's
PCI tray.
The PCI tray accommodates up to four user installed PCI cards. The PCI
cards must be standard +5 Vdc bus signalling cards.
Your system must be running version 10.20 or later of the HP-UX operating
system.
The PCI module does not support HIL devices.