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Cisco Broadband Cable Command Reference Guide
OL-1581-08
Chapter 2 Cisco CMTS Configuration Commands
cable downstream if-output
cable downstream if-output
To activate a downstream port on a cable interface and to generate either a standard modulated signal or
a test signal, use the
cable downstream if-output
command in cable interface configuration mode. To
disable all signal output on the intermediate frequency (IF) carrier and to shut down the interface, use
the
no
form of this command.
cable downstream if-output
[
continuous-wave
|
prbs
]
no cable downstream if-output
Syntax Description
Defaults
The downstream interface is enabled for normal data use (
cable downstream if-output
).
Command Modes
Interface configuration (cable interface only)
Command History
Usage Guidelines
Typically, a downstream is configured to output a modulated signal, using the
cable downstream if-
output
command, allowing data transmissions to be sent over the HFC cable network. However, this
command can also be used to test the cable plant or to shut down the interface completely:
•
cable downstream if-output continuous-wave
—Generates an unmodulated, continuous sine wave
on the downstream interface. You can use a spectrum analyzer to verify the frequency, amplitude,
and power of the wave. The test signal continues on the downstream until you resume normal
modulated operations using the
cable downstream if-output
command.
•
cable downstream if-output prbs
—Generates a PRBS test signal on the downstream interface. You
can use a spectrum analyzer to verify the frequency, amplitude, and power of the wave. The test
signal continues on the downstream until you resume normal modulated operations using the
cable
downstream if-output
command.
•
no cable downstream if-output
—Terminates all signal output and shuts down the downstream
interface. The interface remains shut down until you reactive the downstream using the
cable
downstream if-output
command.
continuous-wave
Outputs an unmodulated carrier signal on the downstream, shutting down
normal data network operations.
prbs
Outputs a Pseudo Random Bit Stream (PRBS) test signal on the downstream,
shutting down normal data network operations.
Release
Modification
11.3 XA
This command was introduced.
12.0(7)XR2, 12.0(7)T,
12.(0)SC,12.1(2)EC1
This command was modified to support Annex A (EuroDOCSIS)
downstreams, and the
continuous-wave
and
prbs
options were added.
