IBM IntelliStation A Pro 6224, Руководство по техническому обслуживанию и ремонту, Страница: 69 / 172

Serial connectors
There are two serial connectors on the rear of the computer. Use these connectors
to connect serial devices. The following illustration shows a serial connector.
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Ultra320 SCSI connector
The computer has an integrated SCSI controller. This dual-channel controller
supports two independent, Ultra320 SCSI channels that support up to 15 SCSI
devices each. The SCSI connectors for the channels are on the system board. The
controller has the following features:
v
Double-transition clocking to achieve up to 320 MBps (megabytes per second)
data-transfer rates
v
Domain name validation to negotiate compatible data-transfer speeds with each
device
v Cyclic-redundancy checking (CRC) to improve data reliability
v
An active terminator for SCSI bus termination
The following illustration shows a SCSI connector.
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SCSI cabling requirements
You can install four internal SCSI devices using the SCSI signal cable that comes
with some computer models. If you plan to attach external SCSI devices, you can
order an additional SCSI cable, remove the SCSI knockout from the rear of the
computer, and connect the new cable from the SCSI channel B connector on the
system board to this opening. To select and order the correct cables for use with
external devices, contact your IBM reseller or IBM marketing representative. See
“System-board internal connectors” on page 77 for the locations of the SCSI
connectors.
If you want to attach external SCSI devices to the computer without using the
internal SCSI channel B, you must install an optional SCSI adapter.
Setting SCSI IDs
Each SCSI device that is connected to a SCSI controller must have a unique SCSI
ID. This ID enables the SCSI controller to identify the device and ensure that
different devices on the same SCSI channel do not attempt to transfer data
simultaneously. SCSI devices that are connected to different SCSI channels can
have duplicate SCSI IDs. See the information that comes with the device for
instructions for setting its SCSI ID.
Chapter 4. Customer replaceable units
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