Chapter 4: C4 CMTS General Installation Requirements
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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CMTS is installed in a closed or multi-unit rack assembly, the inlet air temperature could exceed the room ambient air
temperature and/or the air flow may be reduced. In these cases, the C4 CMTS requires a colder room temperature be
maintained to compensate for this type of installation.
CAUTION: As with all electrical equipment, operation at excessive temperature accelerates the deterioration of
components and adversely effects performance. Prevent excessive heat buildup in the rack.
Temperature Monitoring
The C4 CMTS monitors module temperatures at approximately 90-second intervals. If the temperature of a front module
falls below, or rises above its operating range, a TempOutOfRangeNotification SNMP trap is generated for that module. If
the temperature continues to rise to the module’s thermal limit, the card is powered down and a card
TempOverHeatNotification SNMP trap is generated.
The temperature value read during the last 90-second poll is accessible via both the CLI and SNMP. The
show
environment
CLI command will display the current temperature of modules in equipped slots. The card Temperature
object in the cardTable table in the cadEquipmentMib MIB module contains the current temperature of the associated
slot.
As shown the figure below, the Fan Trays circulate the air that cools the chassis. Air is drawn in through the intake vent at
the bottom of the chassis It then moves across the internal components, cooling them as it passes. The warm air is
exhausted through the vent at the top rear of the chassis.
To ensure the proper air flow, make sure blank filler panels are installed in unoccupied front and rear chassis slots. It is also
important to change the fan filter at least every three months, and more often if the air at the site is dusty.
