Compaq AA-RHGWB-TE manual Scsi Signal Converters

Table 2–2: RAID Controller SCSI IDs (cont.)

RAID Controller	Number of SCSI IDs Supported
HSZ80	15
HSG80	N/A

2.7 SCSI Signal Converters

If you are using a standalone storage shelf with a single-ended SCSI interface in your cluster configuration, you must connect it to a SCSI signal converter. SCSI signal converters convert wide, differential SCSI to narrow or wide, single-ended SCSI and vice versa. Some signal converters are standalone desktop units and some are StorageWorks building blocks (SBBs) that you install in storage shelves disk slots.

______________________ Note _______________________

The UltraSCSI hubs could probably be listed here as they contain a DOC (DWZZA on a chip) chip, but they are covered separately in Section 2.8.

The restrictions for SCSI signal converters are as follows:

•If you remove the cover from a standalone unit, be sure to replace the star washers on all four screws that hold the cover in place when you reattach the cover. If the washers are not replaced, the SCSI signal converter may not function correctly because of noise.

•If you want to disconnect a SCSI signal converter from a shared SCSI bus, you must turn off the signal converter before disconnecting the cables. To reconnect the signal converter to the shared bus, connect the cables before turning on the signal converter. Use the power switch to turn off a standalone SCSI signal converter. To turn off an SBB SCSI signal converter, pull it from its disk slot.

•If you observe any “bus hung” messages, your DWZZA signal converters may have the incorrect hardware. In addition, some DWZZA signal converters that appear to have the correct hardware revision may cause problems if they also have serial numbers in the range of CX444xxxxx to CX449xxxxx.

To upgrade a DWZZA-AA or DWZZA-VA signal converter to the correct revision, use the appropriate field change order (FCO), as follows:

–DWZZA-AA-F002

–DWZZA-VA-F001

2–8Hardware Requirements and Restrictions