Tandberg Data VXA-320 (VXA-3) - Manual (Page 55)

O CTOBER 2006 VXA-320 T APE D RIVE 41
SCSI I
NTERFACE
R
EQUIREMENTS
I
NTERNAL
T
APE
D
RIVE
This section describes the cable, connector, and terminator requirements for
the internal High-density, 68-pin LVD SCSI tape drive.
SCSI Cable Requirements
The cable connected to the tape drive SCSI connector must meet the SCSI-3
specifications listed in Table 6-3 .
Caution
Using a noncompliant SCSI cable will degrade VXA-320 performance and can
cause random, nonreproducible errors. Tandberg Data recommends using shielded
cables.
Table 6-3 SCSI cable and connector specifications
Specification Requirement
General Wide, LVD SCSI-3
Connector High-density, 68-pin, male
Maximum length
a
12 meters (39.2 feet)
Stub length ƒ No greater than 0.1 meters should be used off the mainline connection within any
connected equipment.
ƒ The stub length within the tape drive is less than 2.5 centimeters (1 inch).
Impedance Between 90 and 140 ohms.
An impedance of greater than 100 ohms is recommended. To minimize
discontinuities and signal reflections, all cables on the bus should have the same
impedance.
Conductor size 28 AWG (0.08097 mm
2
)
A minimum of 28 AWG will minimize noise effects and ensure proper distribution of
terminator power.
a The maximum length of 12 meters only applies to an LVD SCSI bus. If a single-ended device is connected anywhere on the bus, all devices
on the bus operate in single-ended mode. When operating in single-ended mode, the maximum allowable bus length is 3 meters
(9.8 feet), terminator to terminator. Exceeding the maximum cable length will result in unstable and unpredictable operation.