VDSL Commands
4-107
efm noise-margin
This command sets the noise margin of the selected VDSL port. Use the no form of
this command to disable this feature.
Syntax
efm noise-margin [downstream noise margin] [upstream noise margin]
no efm noise-margin
• downstream noise margin - A measure of the amount of noise that the
downstream VDSL line can tolerate before the signal is affected.
Range: 0-9
• upstream noise margin - A measure of the amount of noise that the
upstream VDSL line can tolerate before the signal is affected.
Range: 0-9
Default Setting
0 (disabled)
Command Mode
Interface Configuration
Command Usage
When rate adaptation is enabled, (see “efm rate-adapt” on page 4-108) the
Signal-to-Noise Ratio (SNR) is an indicator of link quality. The switch itself has
no internal functions to ensure link quality. To ensure a stable link, you should
add a margin to the theoretical minimum Signal-to-noise ratio (SNR). The table
below lists theoretical minimum SNR’s for the VDSL profiles configurable on this
switch.
Profile Name Theoretical Minimum Signal-to-Noise Ratio (dB)
DS1 DS2 US1 US2
Default 10 Not Used 10 Not Used
A1-02OAG-R1 17 Not Used 14 Not Used
A2-02OAG-R1 20 Not Used 14 Not Used
A3-01OAG-R1 23 10 17 Not Used
A4-01OAG-R1 26 20 20 Not Used
S1-03OAG-R1 17 Not Used 20 10
S2-03OAG-R1 20 Not Used 20 14
S3-00OAG-R1 23 10 23 20
S1-16-16 20 10 20 17
A1-34-11 29 20 17 14
S2-16-16A 20 10 20 17
A2-34-11A 29 20 17 14
A3-25-3 26 10 17 Not used
A4-45-5 32 23 17 10
A5-50-7 35 26 23 14
