Wire Color
Lead Designation
(DC Power Supply)
Red
RTN
Green/Yellow
GND
Black
-48 V
Cooling Components
The Acme Packet 3900 must remain well ventilated for reliable and continuous
operation. The cooling features of the chassis include:
•
Fan module
•
Fan Filter
Fans
Cooling Fans
The Acme Packet 3900 chassis pulls cool ambient air into the chassis through two
front-installed intake fans and exhausts heated air through perforated air outlets
located along the rear of the chassis. To avoid overheating the system, do not block
the air intake or exhaust or otherwise obstruct airflow to the unit in any way.
Each individual fan attaches to the chassis with two captive screws, and is powered by
a connector that joins the fan to the motherboard when screwed into the chassis.
Intake Fans
The intake fans are hot-pluggable and are covered by an air filter that prevents excess
dust and contaminants from entering the system. The air filter is retained by the
removable front bezel.
The Acme Packet 3900 automatically adjusts the fan speed based on the current
operational status and environmental conditions. Fan speed regulation is an
automated process that requires no user intervention. You can monitor the status of
the fan speed from the Environment menu.
Each fan is a user-replaceable, hot-swappable component. If the Acme Packet 3900
experiences a fan malfunction and generates an alarm, you must remove the existing
fan and replace it with a fully functioning fan.
Air Filter
The Acme Packet 3900 foam air filter removes airborne particles before they are
drawn into the system chassis. The air filter, which is located behind the front bezel,
can be easily removed for maintenance. The air filter is a field replaceable unit that
should be replaced once every three months.
Chapter 2
Cooling Components
2-10