•
Check the power at your site before router installation (and periodically after installation) to ensure clean
power (free of spikes and noise) is being received.
•
Always disconnect the power source and unplug the power cable before working on the router.
•
Install proper grounding for the site to avoid damage from lightning and power surges.
To avoid electric shock, do not connect safety extra-low voltage (SELV) circuits to telephone-network
voltage (TNV) circuits. LAN ports contain SELV circuits, and WAN ports contain TNV circuits. Some
LAN and WAN ports both use RJ-45 connectors. Use caution when connecting cables. Statement 1021
Warning
Environmental Monitoring Temperature Sensor
The Cisco ASR 901S Series Aggregation Services Router has three temperature sensors on board to detect
over temperature conditions inside the chassis.
•
Inlet temperature sensor
—
Monitors the local air temperature of the board.
The term
inlet
used here refers to the air circulating from the bottom to the top within
the router chassis; inlet
does not
refer to air entering through an inlet or through the fans
because there are no air vents or fans on the router.
Note
•
Board temperature sensor
—
Monitors the air temperature exiting the chassis.
•
CPU temperature sensor
—
Monitors the air temperature on the CPU.
When over temperature is detected it is reported to the processor as an interrupt, where the software generates
the appropriate alarms. If the router reaches a temperature of 248°F (120°C), the power supply cycles itself
to prevent the router from exceeding the maximum temperature while being powered up.
The following table provides the over temperature alert settings.
Description
Threshold
Sensor
Warning
Syslog
Critical
When this limit is reached,
a syslog is generated.
—
—
185°F (85°C)
Inlet
temperature
When this limit is reached,
a syslog is generated.
—
—
185°F (85°C)
Board
temperature
Cisco ASR 901S Series Aggregation Services Router Hardware Installation Guide
OL-29732-01
11
Introduction
Environmental Monitoring Temperature Sensor