IBM eServer 342 xSeries, User Reference Manual

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IBM xSeries 342: User’s Reference
SCSI cabling requirements
If you plan to attach external SCSI devices, you must order a PCI SCSI adapter and
additional SCSI cables. To select and order the correct cables for use with external
devices, contact your IBM reseller or IBM marketing representative.
For information about the maximum length of SCSI cable between the terminated
ends of the cable, refer to the American National Standards Institute (ANSI) SCSI
standards. Adhering to these standards will help ensure that your server operates
properly.
Setting SCSI IDs
Each SCSI device 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.
The hot-swap-drive backplane controls the SCSI IDs for the internal hot-swap drive
bays. However, when you install an internal SCSI device in a non-hot-swap bay, you
might need to set a unique ID for the device. Refer to the information that is provided
with the device for instructions to set its SCSI ID.
SCSI connector pin-number assignments
The following table shows the pin-number assignments for the 68-pin SCSI
connectors.
Pin Signal Pin Signal
1 +Data 12 35 -Data 12
2 +Data 13 36 -Data 13
3 +Data 14 37 -Data 14
4 +Data 15 38 -Data 15
5 +Data P1 39 -Data P1
6 +Data 0 40 -Data 0
7 +Data1 41 -Data 1
8 +Data 2 42 -Data 2
9 +Data 3 43 -Data 3
10 +Data 4 44 -Data 4
11 +Data 5 45 -Data 5
12 +Data 6 46 -Data 6
13 +Data 7 47 -Data 7
14 +Data P 48 -Data P
15 Ground 49 Ground
16 DIFFSENS 50 Ground
17 Term power 51 Term power
18 Term power 52 Term power
19 Reserved 53 Reserved
20 Ground 54 Ground
Table 10. 68-pin SCSI connector pin-number assignments.
34
1
68 35