NV-600LI/RI Managed Industrial Grade VDSL2 CO/CPE Router USER’S MANUAL Ver. A4
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SNR is commonly quoted for electrical signals, it can be applied to any form of signal (such as
isotope levels in an ice core or biochemical signaling between cells). The ratio is usually measured
in decibels(dB)
The signal-to-noise ratio, the bandwidth, and the channel capacity of a communication channel are
connected by the Shannon–Hartley theorem.
In digital communications, the SNR will probably cause a reduction in data speed because of
frequent errors that require the source (transmitting) computer or terminal to resend some packets of
data. SNR measures the quality of a transmission channel over a network channel. The greater the
ratio, the easier it is to identify and subsequently isolate and eliminate the source of noise.
6. Symptom:
Connected the CO Router with CPE Router within 300 meters RJ-11 phone cable got only less than
10 Mbit/s.
Cause:
Some testing program which is base on TCP/IP protocol such as FTP, Iperf, NetIQ, the bandwidth of
testing outcome will be limited by TCP window size.
Solution:
We recommend to test VDSL2 bandwidth best by Smartbit equipment, if you don't have Smartbit,
we recommend test that by IPERF program, and TCP window size must be settled max. 64k, the
parameter as iperf –c server IP address –i 1 –t 50 –w 65535 for client side.
7. Symptom:
VDSL2 CO router cannot link with CPE router.
Cause:
1. The VDSL2 CO/CPE mode settings of VDSL2 router become unknown.
VDSL2 CO and CPE router tone mode is different due to mixed use of new and old hardware
