Setting master/slave jumpers
Two drives may be controlled through a single drive controller
cable with two connectors. In this case, one drive is designated
as the master and the other is designated as the slave. As shown
in Figure 1 on page 4, the jumpers on each drive must be set to
identify which drive is master and which is slave.
Connecting cables
ST9100A and ST9100AG drives use a 44-pin AT interface con-
nector cable with two rows of 22 female contacts on 0.079-inch
(2 mm) centers (see Figure 1). Pin assignments for the AT
interface are listed in Appendix A.
Most cables have a stripe down one side, which designates pin
1. Make sure pin 1 on the interface cable connector is aligned to
pin 1 on the drive interface connector and pin 1 on the host
connector. To assist in cable alignment, pin 20 has been removed
on the male interface connector on the drive. This type of
connector is designed to be used with a keyed cable connector
having a plug in place of pin 20.
Before mounting the drive, be sure that the connecting cable is
long enough to reach the drive, but not so long that it will be
pinched when the system enclosure is replaced. Connecting
cables for the ST9100A and ST9100AG must be no longer than
18 inches (457 mm).

Power connections

Power for the ST9100A and ST9100AG is supplied through the
44-pin interface connector (see Appendix A for specific pin as-
signments).
Caution. These drives can accept only +5 volts DC power. Do
not use +12 volts DC power.
ST9100A and ST9100AG Installation Guide, Rev. A 3