Installation guide

3-3
Cisco uBR7100 Series Universal Broadband Router Software Configuration Guide
OL-2238-03
Chapter 3 Configuring the Cisco Cable Interface
Configuring the Downstream Cable Interface
Verifying the Downstream Carrier
To determine if the downstream carrier is active (up), enter the show controllers cable command for the
downstream port that you just configured. For NTSC 6 MHz operations, see the following example:
CMTS01# show controllers cable1/0 downstream
Cable1/0 Downstream is up
Frequency=96000000, 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
Setting the Integrated Upconverter
The Cisco uBR7100 series router supports an integrated upconverter that outputs a DOCSIS RF signal
on the DS0 RF downstream port. To enable the integrated upconverter, you must do the following:
• Set the downstream frequency—The integrated upconverter must be configured for the digital
carrier frequency, which is the center frequency of the downstream RF carrier (the channel) for the
downstream port. The cable downstream frequency command configures the downstream center
frequency for the integrated upconverter.
Note The cable downstream frequency command has no effect on external upconverters. If you are using an
external upconverter, this command is informational only and you must configure the external
upconverter separately, using its own command procedures.
• Enable the integrated upconverter—The integrated upconverter is disabled by default and must be
enabled with the no cable downstream rf-shutdown command.
• Enable the cable interface—The cable interface on the Cisco uBR7100 series router must be enabled
before the integrated upconverter will output an RF signal.
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
Command Purpose
ubr7100(config)# interface cable 1/0
Enter interface configuration mode for the cable
interface on the Cisco uBR7100 series router.
ubr7100(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).
ubr7100(config-if)# no cable downstream
rf-shutdown
Enable the integrated upconverter.
ubr7100(config-if)# no shutdown
Enable the cable interface.