Advantech PCA-6005-B, User Manual

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PCA-6005-B User’s Manual 70
• In Windowsc 95/98, you can use the Device Manager to determine
which SCSI ID is assigned to each installed SCSI device.
6.4 Terminating the SCSI Bus
To ensure reliable communication on the SCSI bus, the ends of the SCSI
bus must be properly terminated. This is accomplished when the device at
the end of the each cable, or the end of the cable itself, has a terminator
installed (or enabled). Terminators must be removed, or termination must
be disabled, on devices between the ends of each cable.
Since the method for terminating a SCSI device can vary widely, refer to
the device.s documentation for instructions on how to enable or disable
termination. Here are some general guidelines for termination:
• Internal Ultra 160 and Ultra 2 SCSI devices come from the factory with
termination disabled and cannot be changed. Proper termination for
internal Ultra 160 and Ultra2 SCSI devices is provided by a 68-pin
Internal LVD (low voltage differential) SCSI cable, which has a built-
in terminator at its end.
• Termination on non-Ultra 160 and Ultra2 internal SCSI devices usually
is controlled by manually setting a jumper or a switch on the device, or
by physically removing or installing one or more resistor modules on
the device.
• Termination on most external SCSI devices is controlled by installing
or removing a SCSI terminator. However, termination on some exter-
nal SCSI devices is enable or disabled by setting a swetich on the back
of the SCSI device.
The last external Ultra160 or Ultra2 SCSI device must be terminated with
an LVD/SE (low voltage differential/single ended) terminator plug to
ensure that the device will operate at its maximum speed. If you use a dif-
ferent kind of terminator plug, the data I/O rate will decrease.
By default, termination on the SCSI controller itself is set to Automatic
(the preferred method). We recommend that you do not change this
default setting.