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Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide
OL-2239-03
Chapter3 Configuring Cable Modem Interface Features
Configuring the Upstream Cable Modem Interface
Router(config-if)# no cable upstream usport power-adjust noise
To return the upstream power-adjustment threshold value to the default of 1dB, enter the following
command in cable interface configuration mode:
Router(config-if)# no cable upstream usport power-adjust threshold
Verifying Upstream Power Adjustment
To determine if upstream power adjustment is configured and activated, enter the showrunning-config
command and look for the cable interface configuration information. If upstream power adjustment is
enabled, any or all three of the continue, noise, and threshold power-adjustment entries appear in the
show running-config command output. If all three upstream power adjustments are disabled, no
power-adjustment entry appears in the showrunning-config command output.
Activating the Upstream Scrambler
The scrambler on the upstream RF carrier enables CMs on the HFC network to use built-in scrambler
circuitry for upstream data transmissions. The scrambler circuitry improves reliability of the upstream
receiver on the cable interface line card.
Caution The upstream scrambler is activated by default and should not be disabled under normal circumstances.
Disabling it can result in corrupted packets. Disable it only for prototype modems that do not support
the upstream scrambler.
To activate the upstream scrambler, use the following command in cable interface configuration mode.
The upstream scrambler is enabled by default.
Router(config-if)# cable upstream usport scrambler
Verifying the Upstream Scrambler
To determine if the upstream scrambler is activated, enter the moresystem:running-config command
and look for the cable interface configuration information. Perform these steps if you are having
difficulty with verification:
Step1 Ensure that the cable connections are not loose or disconnected.
Step2 Ensure that the cable interface line card is firmly seated in its chassis slot.
Step3 Ensure that the captive installation screws are tight.
Step4 Verify that you have entered the correct slot and port numbers.
Step5 Verify that you selected a valid frequency for your router.
Activating Upstream Timing Adjustment
To enable upstream timing adjustment for a specified cable interface, use one of the following commands
in cable interface configuration mode.