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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CAUTION: The C4 CMTS generates a significant amount of heat. Allow enough space around the C4 CMTS for adequate
ventilation and do not block the air vents. Inadequate ventilation could cause the system to overheat.
Clearance
Allow sufficient clearance around the rack for maintenance. If the rack is mobile (not recommended), place the C4 CMTS
near a wall or cabinet for normal operation and pull it out for maintenance (installing or moving port adapters, connecting
cables, and replacing or upgrading components). Be sure there is enough cable length available to pull the C4 CMTS out for
repairs or adjustments if necessary.
Power Requirements
The C4 CMTS uses dual redundant -48V power feeds to supply electrical power to the system. The system is capable of
operating from a single feed in case one of the feeds fails.
The system consumes a maximum of 2800W of power when equipped with the maximum number (16) of CAMs.
The supply voltage should be a nominal -48V. The operating range is -44 to -72V. The system will shut down if the voltage
is outside these limits.
The -44V guaranteed operating limit translates to a maximum current draw of 64A at 2800W. Circuit breakers on the
power feeds should be sized accordingly. The Power Conditioning Modules in the C4 CMTS will limit the startup current to
prevent false tripping of the circuit breakers.
Cooling Requirements
The C4 CMTS should be installed in a location with adequate ventilation. It is designed for long-term operation at ambient
air temperatures ranging from 5-40
C and an area that is between 5 to 95 percent relative humidity, non-condensing.
To determine cooling requirements, assume 2800W for worst-case power dissipation. These values assume the worst-case
cooling requirements when the maximum number of CAMs (16) is used.
The C4 CMTS draws cooling air in through the front, sides, and back at the bottom of the unit and expels it out the sides
and back at the top of the unit. Clear airflow must be maintained in these areas to ensure adequate ventilation. If the C4