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Chapter 4: C4 CMTS General Installation Requirements

STANDARD Revision 1.0 C4® CMTS Release 8.3 User Guide

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

Arris C4C User Manual

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