3Com DSA-3CV1100-02 service manual SNR, signal to noise ratio, Reset All Counters

68 MANAGING THE VCN ACCESS CONCENTRATOR

Figure 41 VDSL QAM Channel Status Report

QAM channel status

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QAM status:	In lock
VDSL restarts:	1
VDSL warm starts:	0
Downstream parameters
DS Symbol rate:	1.964	Mbaud
DS Constellation:	2^5
DS Bit rate:	9.820	Mbps
SNR(@QPSK):	40.250 dB
Upstream parameters
US Symbol rate:	4.910	Mbaud
US Constellation:	2^2
US Bit rate:	9.820	Mbps
SNR(@QPSK):	36.932 dB
SNR Estimate:	36.27	dB

Press <Enter> to continue ...

Figure 41 contains the following information:

■QAM Status: In lock—the line to the VCN AP is connected.

The alternate state is Out of lock—the line to the VCN AP is not connected.

■Restarts, the number of times the line to the VCN AP undergoes a cold restart. A cold restart occurs when there is a prolonged break in the line.

■Warm restart, a restart using information that existed the previous time the link was operational. A warm start occurs when the line is briefly disconnected or line noise occurs over a period of time.

■SNR, signal to noise ratio.

Reset All Counters

To reset all traffic counters, type 4 in the Management Menu (Figure 31) and press <Enter>; the message appears:

Do you want to proceed (Y/[N])?