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CHAPTER 3: Before You Install: Getting Started
NOTE
If you mix Wide and Narrow devices on the same side (internal or
external) of a SCSI bus attached to the Adapter, we strongly recommend
that all of the Narrow devices be attached to the bus
closer to the
Adapter
than all of the Wide devices. If you attach any Narrow devices at
the far end of the bus, beyond any Wide devices, you’ll have to be
very
careful
to terminate the Wide lines (Pins 51 to 68) of the last Wide device.
Alternatively, you can “hardwire” the Adapter so that termination is always ON by
installing jumpers on the Adapter’s circuit board. The most common application
for which you would hardwire-enable termination is this: installing multiple
Adapters in multiple PCs, but attaching them to the same bus in order to share
peripherals. In such situations, you might want to hardwire termination ON for any
Adapters that are on the end of the bus, so that you can turn off the computers in
which those Adapters are installed without losing termination power and disabling
the SCSI bus. If for this (or whatever) reason you do want to hardwire termination
ON, you need to install a jumper on the Adapter before you put it in your PC.
(Once this jumper is installed, it will override the termination setting in the
Adapter’s firmware.) The jumper should be installed at location JP1, as shown in
Figure 3-3 below.
Figure 3-3. Hardwiring termination.
SE
L
V
D
TERM
A
C
T
VCC
LED
+
LED
–
VCC
1
4
JP1 TERMINATION
1–2
NO JMP
SW CNTRL
< Default >
Always OFF
JP1:
Termination
Jumper