Digital Equipment VAX 4000 500A Operation page 26

System
DSSI VAXcluster systems should not be configured with a Power Bus.
Inadvertently shutting off a system defeats the added reliability of a DSSI
VAXcluster configuration.
The main out (MO) connector sends the power control bus
signal to an expander. One end of a Power Bus cable is
connected here; the other end is connected to the secondary
in (SI) connector on the expander power supply.
The secondary in (SI) connector receives the power control
bus signal from the main power supply. In a Power Bus with
more than one expander, the power control bus signal is passed
along, using the secondary in and out connectors.
The secondary out (SO) connector sends the power control
bus signal down the Power Bus for configurations of more than
one expander.
1–18 System Overview
Expander 1 Expander 2
Note
MLO-004041