3
Expanding Your System
This chapter provides information on installing and using external add-on disk
storage devices. An InfoServer 150 system can support 5 external SCSI devices
on SCSI bus A and 7 external SCSI devices on SCSI bus B.
Digital qualifies the external expansion boxes recommended for use with the
InfoServer 150 system, to ensure that they meet system requirements.
The chapter explains how to perform the following tasks:
•
Connect one or two expansion boxes of the same type to your system unit
•
Verify the SCSI ID default (factory) setting
•
Reset the SCSI ID number
The chapter also provides some specific information for the RRD42 expansion
box.
3.1 Guidelines for Connecting Expansion Boxes
Use the following guidelines when connecting expansion boxes:
•
You can connect any combination of external expansion boxes, as long as
you do not connect more than 12 expansion boxes.
•
You must attach the 50-pin terminator that comes with your expansion box
to an unused bottom SCSI connector on the back of an expansion box.
•
You should plug all expansion boxes into the same grounded power strip or
electrical outlet.
CAUTION
Some expansion boxes are restricted to either 110 Vac or 220 Vac
operation. Make sure the voltage requirement of any expansion box
is compatible with the supply voltage. The RRD42 expansion box
accepts power inputs in the ranges of 100 Vac to 120 Vac and 200 Vac
to 240 Vac, at 50 or 60 Hertz. Within these limits the power supply
3–1
