ZyXEL Communications MSC1024G Series User Manual page 801

[snrmodeds disable|enable]
[snrmodeus disable|enable]
[refvnds <tone_index> <vn_psd>
[...]
[refvnus <tone_index> <vn_psd>
[...]
[dpboescma <escma>]
[dpboescmb <escmb>][dpboescmc
<escmc>]
[dpboesel <esel>]
[dpbomus <mus>]
[dpbofmax <fmax>]
[dpbofmin <fmin>]]
MSC1000G/1024G/1224G Series User's Guide
Chapter 32 profile Commands
= Enables or disables the downstream (ds) or
upstream (us) transmitter reference virtual noise.
= Adds virtual noise levels on downstream (ds) or
upstream (us) tones where actual noise may
occur.
If there is too much noise on a line, the allowed line
speed may be reduced or the line may not
initialized. Virtual noise is the noise allowed before
adjustment occurs. Switch then uses lower data
rate on tones which you added a noise level for the
line initialization. Lower data rate increases a line's
stability and avoid the line to be easily dropped
when actual noise occurs. The Switch adds pre-
configured virtual noise on specified set of
breakpoints. used to avoid a VDSL line assigning
an overly optimistic number of bits to a sub-carrier.
When the actual noise increased, the actual SNR
margin is enough to maintain the bit-loading, and
not leads to line drop. That is, the virtual noise
adding can increase the line's stability.
<tone_Index>: 1~4096 in units of 4.3125 kHz, 0
means not used
<vn_psd>: 0~200 (representing a PSD of -
140+psd/2 dBm/Hz)
= These parameters define a cable model that is
used to describe the frequency dependent loss of
exchange-side cables.
<escma>: DPBO A parameter, 0~640 represent -
1~1.5 in step of 1/256
<escmb>: DPBO B parameter, 0~640 represent -
1~1.5 in step of 1/256
<escmc>: DPBO C parameter, 0~640 represent -
1~1.5 in step of 1/256
= Specify the electrical length of the cable between
the system and CPE devices.
<esel>: Electrical length of DPBO, 0~511 (in units
of 0.5dB)
See Section 11.2.9 on page
= Set the assumed minimum usable received PSD
mask (in dBm/Hz) for exchange based services,
used to modify parameter DPBOFMAX defined
below. Enter from 0 to 255 to set the PSD to 0~-
127.5 dBm/Hz in steps of -0.5 dBm.
= This defines the maximum frequency at which
DPBO may be applied.
<fmax>: 32~6956 (units of 4.3125kHz)
= This defines the minimum frequency from which
the DPBO shall be applied.
<fmin>: 0~2048 (units of 4.3125kHz)
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