Product manual

50 Barracuda 2LP Product Manual, Rev. D
10.1.2 ST31250W/WD and ST32550W/WD configuration
Figure 20 illustrates ST31250W/WD and ST32550W/WD option select
jumper connectors.
SCSI I/O
Connector
DC Power
Connector
ST31250W and
ST32550W
J1 Connector
ST31250WD and
ST32550WD
J1 Connector
J5
Pin 1
Pin 1
J4
Fault LED pin (–)
Vendor unique
SSREF (+) 
spindle sync
Unit Active
LED pin (–)
Enable SCSI
terminator*
Ground
+5V
SCSI ID bit 1
SCSI ID bit 2
J4
J1
Pin 4
Pin 3
Pin 2
Pin 1
Pin 1
Pin 1
SCSI ID bit 0
SCSI ID bit 3
(front view of J4)
Pin 2
Disable SCSI Parity
Write Protect
J2
Pin 1
Enable Motor Start
Pin 2
Delay Motor Start
Term. power from
drive (default)
J1
Pin 1
Pin 2Pin 6
Pin 4
Pin 2
Pin 1
Pin 3
Pin 1
ST31250WD and
ST32550WD
ST31250W and
ST32550W
Term. power to 
SCSI Bus (default)
Term. power to 
SCSI bus
Term. power from 
SCSI bus
Term. power to 
SCSI bus and drive
Enable SCSI 
terminator (default)
Reserved
No connection
Reserved
J2
SCSI ID = 1
SCSI ID = 2
J5
SCSI ID = 3
Pin 1
SCSI ID = 4
SCSI ID = 0 (default)
SCSI ID = 6
SCSI ID = 7
SCSI ID = 8
SCSI ID = 9
SCSI ID = 5
SCSI ID = 11
SCSI ID = 12
SCSI ID = 13
SCSI ID = 14
SCSI ID = 10
SCSI ID = 15
Remote LED Connector
Spindle Sync 
Cable Connector
SSREF
*ST31250W and ST32550W only (internal 
termination is not available on ST31250WD 
and ST32550WD drives).
Cathode (–)
Anode (+)
Pin 1 End
Figure 20. ST31250W/WD and ST32550W/WD jumper connectors