8 Operation on an SHDSL Access
ARGUS 145
PLUS
125
The ARGUS determines the following SHDSL connection parameters:
SHDSL connection parameters
SNR Margin
Signal-to-noise ratio in dB The SNR margin is a measure of how
much additional noise the transmission can withstand and still
achieve a BER (Bit Error Rate) of at least 10
-7
.
SNR margin = 0 dB -> BER = 10
-7
-> SNR = 23 dB
SNR
SIgnal-to-noise ratio in dB, also see SNR margin.
Attenuation (dB)
The line’s attenuation in dB over its entire length
Output power (dBm)
Output power referenced to 1mW
CRC
Cyclic Redundancy Check
Number of all CRC anomalies (CRC6 checksum errors), also
known as Code Violations (CV). The ARGUS adds up the
number of CRC errors in the one-second periods.
LOSWS
Loss of Sync Word Seconds
The number of seconds in which one or more sync word errors
occurred.
ES
Errored Seconds
The number of seconds in which one or more sync word errors
occurred and/or one or more CRC anomalies occurred.
SES
Severely Errored Second
The number of seconds in which one or more sync word errors
occurred or at least 50 CRC anomalies occurred.
US
Unavailable Seconds
Number of seconds in which the SHDSL connection was not
available. When 10 SESs have occurred in a row, the
connection is no longer available. The 10 SESs are counted as
part of the time that the connection is not available. Once the
connection has become unavailable, it will only be considered to
be available again when 10 seconds pass in which no SESs
occur. The 10 seconds without SESs are not counted as part of
the time that the connection is not available.
