Seagate ST39173N/W/WD/LW/WC/LC manual Cable characteristics for differential I/O circuits

26Barracuda 9LP Installation Guide, Rev. E

Table 4b. Cable characteristics for differential I/O circuits

	Maximum distance between
	terminators (meters) [1] [3]
Interconnect	Fast-5	Fast-10	Fast-20	Fast-40
Point-to-point interconnect
(2 devices)	25	25	25	25 [2]
Daisy-chain interconnect
(up to 16 devices)	25	25	25	12 [4]

[1]For environments where all elements of the bus (cables, device inter- faces, environmental noise and other parameters) are controlled to be better than minimally required, it may be possible to extend the path length and device count.

[2]SCSI devices shall be within a stub length of the termination (.1 meter).

[3]Values specified by data rate shall apply even if a slower data rate is negotiated.

[4]Low voltage differential (LVD) devices only (“LW” models).

Twisted pair cable should be used with differential transceivers.