ZyXEL Communications Cable Modem, Руководство пользователя

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Chapter 1 VLC Overview
VLC1324G User’s Guide
16
VDSL2 Compliance
• ITU-T
-G.993.2
-G.994.1
Discrete Multi-Tone (DMT) Modulation
The VLC is a DMT-based VDSL2 solution which dynamically adapts the bit transfer rate to
conditions on the local loop. This allows the line card to sustain high performance even over
noisy lines.
Transmit PSD Notches
The VLC supports the transmission of PSD (Power Spectral Density) notches at RFI (Radio
Frequency Interference) bands. This reduces the effects of strong radio sources nearby.
Upstream Power Backoff
Upstream Power Backoff (UPBO) methods can be applied to VDSL2 networks, in order to
solve FEXT (Far End Cross (X) Talk) noise effects in distributed environments.
Downstream Power Back-Off
The VLC1324G-51 supports the downstream power back-off (DPBO) in ITU-T G.997.1 to
reduce far-end crosstalk.
Band Plan Support
The VLC supports the band plans defined in ITU-T G.993.2.
Alarm Profiles
The system allows you to customize the priority levels of individual alarms and the alarm
severity threshold for recording alarms on an individual port(s). The VLC also includes a DSL
error (ES, SES, UAS) monitoring and alarm reporting mechanism.
VDSL2 Profiles
Profiles allow you to configure VDSL2 ports efficiently. You can configure all of the VDSL2
ports with the same profile, thus removing the need to configure the VDSL2 ports one-by-one.
You can also change an individual VDSL2 port by assigning it a different profile. The VLC
supports the following VDSL2 profiles:
• The DS1 frequency band of the 17a profile starts at 138 kHz and the edge frequency of the
upper band of the 17a profile is 17.664 MHz.
• The VDSL2 profiles are programmable and automatically adapt according to the line
condition of each VDSL2 line.
• 8a • 8b
• 8c • 8d
• 12a • 12b
• 17a