ZyXEL Communications IES-1248 VDSL-SWITCH User Manual page 179

LABEL
QLN The Quiet Line Noise for a DMT sub-carrier is the rms (root mean square) level of the noise
present on the line, when no ADSL signals are present. It is measured in dBm/Hz. The QLN can
be used in analyzing crosstalk.
SNR This is the upstream and downstream Signal-to-Noise Ratio (in dB). A DMT sub-carrier's SNR is
the ratio between the received signal power and the received noise power. The SNR can be
used in analyzing time dependent changes in crosstalk levels and line attenuation (such as
those caused by temperature variations and moisture).
Diagnostic
Table 25-4 Line Diagnostics Test Parameters
DESCRIPTION
IES-1248 Ethernet Switch
25-5