Setting The Snr-Margin - HP ProCurve Secure 7000dl Series Basic Management And Configuration Manual

Table 7-4. Training Modes Supported by the ProCurve Secure Router
Command Option
training-mode ADSL2
training-mode ADSL2+
training-mode G.DMT
training-mode G.LITE
training-mode Multi-Mode
training-mode READSL2
training-mode T1.413
To define the training mode, enter the following command from the ADSL
interface configuration mode context.
Syntax: training-mode [ADSL2 | ADSL2+ | G.DMT | G.LITE | Multi-Mode | READSL2 |
T1.413]
For example, to set the training mode for ADSL2, enter:
ProCurve(config-adsl 2/1)# training-mode ADSL2
The default setting for both the ADSL2+ Annex A module and the ADSL2+
Annex B module is Multi-Mode.

Setting the SNR-Margin

Because ADSL connections are affected by line interference, you must specify
the level at which the quality of the signal on the ADSL line is acceptable. This
quality of the signal is determined by the signal-to-noise ratio (SNR) margin.
The SNR margin is calculated logarithmically. An SNR margin of 15 means the
signal is approximately 5.6 times stronger than background noise, while a
signal with an SNR margin of 1 is only marginally stronger than the background
noise.
Because transmission speeds on ADSL lines are affected by line interference,
you want to maximize the signal and minimize the background noise. When
you narrow the signaling band to maximize the signal, however, you also
decrease the transmission rate.
ADSL WAN Connections
ADSL Modules for the ProCurve Secure Router
ADSL2+ Annex A ADSL2+ Annex B
Yes Yes
Yes Yes
Yes Yes
Yes No
Yes Yes
Yes No
Yes No
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