Chapter 8: Downstream Cable Access Modules (DCAMs)
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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The maximum per-channel power level is determined by the number of channels assigned to a cable MAC on the same F-
connector. The following factors do not determine the per-channel power levels:
the administrative or operational state of the channels
the frequency of the channels (even 0 MHz)
muting the channel.
For example, if the power level is set to 60 dBmV, and if you try to add a second channel to the same F-connector, then
the CLI will allow this second channel to be added to the same F-connector as long as it has not been added to a cable-
mac. But the command to add this second channel to a cable-mac will fail because 60dBmV is not a valid power level
for two channels on the same connector. If the power level for the first channel has been set to 60 dBmV and the
second channel has already been assigned to a cable-mac, then the CLI will reject the command to assign this second
channel to the 60 dBmV F-connector.
Other operational notes:
If the power level is changed for one channel, the power level for all other channels associated with the same F-
connector is also changed.
The command to reconfigure the power level fails if the chosen power level is outside of the range shown in the table
above.
Enhanced power for Annex A XD CAMs can be enabled using the CLI command configure cable downstream-
enhanced-power.
Note: RF performance may be degraded at the higher output power permitted in the enhanced power mode.
RF Power Monitoring and Recovery
The 16D and XD CAMs monitor the out-of-tolerance power loss on in-service channels. This is accomplished by logging an
event when the actual RF output power deviates either positively or negatively from the provisioned values. A warning is
logged when the monitoring identifies a deviation of +/- 3 dBmV. A recovery, or failover mode, occurs after an RF power
deviation of +/- 6 dBmV.
When recovery is enabled, if the RF power output exceeds the configured recovery value, then the XD CAM automatically
attempts to recover and may go into failover mode.