Terminate The Ends - Adaptec AAA-130SA SERIES Installation And Hardware Manual

Installing the AAA-13xSA RAID Card and Connecting SCSI Peripherals

Terminate the Ends

To ensure reliable communication on the SCSI bus, terminators must
be installed (or enabled) on the peripherals at the physical ends of
each SCSI channel. The peripherals between the physical ends of
each SCSI channel must have the terminator removed (or disabled).
Terminating SCSI Channels on the AAA-13xSA RAID Card
Termination on the AAA-13xSA RAID card itself is controlled via
™
the SCSISelect
on the AAA-13xSA RAID card set to its default setting of Auto Mode
(the terminators are enabled or disabled according to the SCSI con-
nectors in use). If you want to manually disable the AAA-13xSA
RAID card termination setting, see Chapter A, Configuring the
AAA-13xSA RAID Card with SCSISelect.
Terminating SCSI Peripherals
On most internal SCSI peripherals the termination setting is con-
trolled by setting a jumper or a switch, or by physically removing or
installing a resistor module(s). On most external SCSI peripherals,
termination is controlled by installing or removing a terminating
plug (see Figures 2-14 and 2-15). Read the peripheral's documenta-
tion to determine how to enable or disable termination on your par-
ticular peripheral.
The internal SCSI cables supplied in Adaptec AAA-13xSA RAID
card kits have attached terminators, so you should disable termina-
tion on all internal SCSI peripherals connected to the cable. In gen-
eral, we recommend that you terminate the internal cable instead of
terminating the SCSI peripherals. If you are using an external array
enclosure, we recommend that you terminate the SCSI backplane or
install an active terminator on the second SCSI connector on the rear
panel instead of terminating the individual SCSI peripherals. If you
follow these recommendations, SCSI bus termination will not be
affected when you remove or replace SCSI peripherals.
Note:
We recommend that you enable termination power on
all SCSI peripherals in the server so that termination power
will still be supplied if you replace one or more drives on
the SCSI bus.
utility. We recommend that you leave each channel
2-7