AT&T 3B2 Maintenance Reference Manual page 275

Feature Cards
Expansion Disk Controller Card
The expansion disk controller (XDC) is an I/O expansion card that allows up to two additional
hard disks to be added to the system. The XDC is designated CM195K and uses the same
hard disk controller chip as the system board, allowing any drives available as integral disks to
be connected as expansion disks. The supported growth limits are two XDC cards in the
300/310 and four XDC cards in the 400, with a maximum of 6 and 10 hard disk drives,
respectively. Figure 8-21 represents the XDC card.
HARD DISK DATA 1
HARD DISK DATA 0
HARD DISK
CONTROL
CONNECTOR
(DAISY-CHAINED)
STRAIN
RELIEF
SCREWS
Figure 8-21. Expansion disk controller (XDC) card CM195K
110
Feature
Cards 8-35