Efm noise-margin – Accton Technology VS4512DC User Manual
Page 253
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