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Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide
OL-2239-03
Chapter3 Configuring Cable Modem Interface Features
Configuring the Downstream Cable Modem Interface
To configure the integrated upconverter, use the following commands in cable interface configuration mode.
Verifying the Integrated Upconverter Configuration
To verify the configuration for the integrated upconverter, enter the show controllers cable downstream
command. The following is a typical display with a correctly configured center frequency:
Router# show controllers cable1/0 downstream
Cable1/0 Downstream is up
Frequency=525000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 Msps
FEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4
Downstream channel ID: 0
Then enter the show controllers cable command, which also displays the center frequency, along with
the power levels and whether the integrated upconverter is enabled. The following is a typical display
when these values have been correctly configured:
Router# show controllers cable1/0
Interface Cable1/0
Hardware is IMC11
BCM3210 revision=0x56B2
Cable1/0 Upconverter is Enabled Output is Enabled
Model: 74-2094-01 Serial Number: 0WAV04480010 CLEI Code: CLEI#
HW Rev: PC2D0107 SW Rev: 007, NVRAM Rev: 006 ECI number 123456
Downstream Frequency 525.0000 MHz
IF Power 0.3 dBmv RF Power 51.0 dBmv
...
If the center frequency has not been configured, the frequency is shown as “not set” as shown in the
following example:
Router# show controllers cable1/0 downstream
Cable1/0 Downstream is up
Frequency is not set. Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 Msps
FEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4
Downstream channel ID: 0
If you are having trouble, make sure the cable connections are not loose or disconnected, and that you
have calculated and entered the center frequency for your router accurately.
Assigning the Downstream Channel ID
To assign a numeric channel ID to the downstream port on the Cisco cable interface line card, use the
following command in cable interface configuration mode. The acceptable range is 0 to 255.
Router(config-if)# cable downstream channel-id id
Command Purpose
Router(config)# interface cable 1/0
Enter interface configuration mode for the cable interface
on the CiscouBR7200series router.
Router(config-if)# cable downstream
frequency down-freq-hz
Enter the fixed center frequency for your downstream RF
carrier in Hz. Allowable DOCSIS center frequencies are
91,000,000 to 857,000,000 Hz (the default is 500,000,000 Hz).
Router(config-if)# no cable
downstream rf-shutdown
Enable the integrated upconverter.
Router(config-if)# no shutdown
Enable the cable interface.