Specifications

2-14 Reference Guide
Model No.
Running Head
System Power and Ground Connections System Installation
2.5.1 Two-Sided Chassis
Figure 2-9 shows the power connector block on the front-loading chassis with power supplies
on the side, and on the two-sided chassis.
Connect the grounds and DC power signals to this block by inserting the wires in the proper
slots, then tightening the screws adjacent to the slots to secure the connections. For safety
reasons, no more than one-eighth inch (0.125") of each connecting wire should be exposed.
No uninsulated wire should be visible from the power connector block.
The power connector block also provides dual power connections at
V
A
and
V
B
where
redundant power feeds are required. The
V
A
pins feed power supply slot F1, and the
V
B
pins
feed power supply slot F2.
In addition, you can connect the
V
N
pins of the block to an external -48V source for powering
voice cards and their circuits. The
COM
(common) pin is for a signal ground connection, and
the
RGR
(ringer) pin is for an external 20 Hz ringing input to the chassis. The ringing voltage
bias is selected by a connection to V
N
+ or V
N
-.
Note:
If -48 VDC is applied to V
A
or V
B
, DO NOT connect external power to V
N
.