Seagate ST136475LW/LC manual Terminator power, Circuits and data path widths

22 Barracuda 36 Installation Guide, Rev. B

For information about how to terminate your drive, refer to the appropriate drive-specific section.

Internal SCSI cable

Internal	Internal
SCSI device	SCSI device

Controller

Terminate

Internal SCSI cable

Internal	Internal	Controller
SCSI device	SCSI device

External

SCSI cable

External

SCSI device

External

SCSI device

Terminate

Figure 2. SCSI bus termination

Terminator power

You usually will not need to change this option and can normally leave the drive configured as it was shipped from the factory. For information about how to change the terminator power option on your drive, refer to the appropriate drive-specific section.

I/O circuits and data path widths

•“LW” and “LC” models use SCSI multimode I/O circuits. Multi- mode circuits operate either in single-ended mode or low volt- age differential mode. No high voltage differential devices should be connected in the I/O daisy chain with “LW” or “LC” model drives. The state of the I/O “DIFFSNS” line determines whether the devices on the SCSI bus operate their I/O circuits in single-ended or low voltage differential mode. The host device on the SCSI bus operates the “DIFFSNS” line. How- ever, the SE jumper on J2 forces “DIFFSNS” to nominal