Technical information

ADC Telecommunications, Inc.
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HAPTER 18: CONFIGURING AND MONITORING CABLE MODEM TERMINATION SYSTEMS
Table 18-5 Downstream Window Parameters.
Parameter Description
Channel Status Normally, displays the current status of the downstream
channel, and allows you to set the status of the channel. Up
indicates that the channel is active; Down indicates that the
channel is inactive.
To set the channel to a different state, from the drop-down
menu choose the channel state that you want.
Channel ID Each Cuda 12000 DOCSIS and EuroDOCSIS has a single
downstream channel, so the Channel ID is fixed at 1.
Downstream
Center
Frequency
(MHz)
Sets the downstream signal for the RF carrier. Following are
default and range values for DOCSIS and EuroDOCSIS
configuration. By default, Center Frequency is set at 507.0
MHz. The acceptable values are:
■ DOCSIS — 93.0 MHz to 855 MHz.
■ EuroDOCSIS — 91.0 MHz to 858 MHz.
Channel Width
(MHz)
Read-only. The fixed channel width, which is based on
DOCSIS and EuroDOCSIS standards and defined by the NTSC
channel plan. A DOCSIS module is set at 6 MHz, and a
EuroDOCSIS module is set at 8 MHz.
Channel Power
(TenthdBmV)
Sets the nominal output transmit power level. By default,
Channel Power is set at 550 TenthdBmV. Acceptable values
are 0-650.
Downstream
Channel
Modulation
Ty pe
Sets the modulation rate for a downstream port. The CMTS
supports the following two modulation types. The options
are:
■ qam 64 - sets the interface speed at 30 Mbps
■ qam 256 - sets the interface speed at 40 Mbps
WARNING: You should know the following about setting
Downstream Channel Modulation:
Before issuing a downstream modulation change, changes
made to any other CMTS parameters should first be
persisted.
Setting a new downstream modulation to a DOCSIS or
EuroDOCSIS module causes the new downstream
modulation value to be saved in flash and the module to
reset. After the module completes reset, it runs with the new
downstream modulation.