C
HAPTER
4
| Status Information
DSL Statistics
– 54 –
The following items are displayed on this page:
Mode — Displays the connection mode for the ADSL Router, which is
fixed at ADSL2+.
Latency — Displays the hop-count - the number of routers your
packets must navigate before they reach the destination.
Trellis Coding — Displays Trellis modulation (also known as trellis
coded modulation, or simply TCM) - a modulation scheme which allows
highly efficient transmission of information over band-limited channels
such as your telephone line.
Status — Displays the ADSL connection status (“activating”, “up” or
null).
Power Level — Displays the power level employed for ADSL port
filtering.
DOWNSTREAM/UPSTREAM
Refers to statistics either downloaded or uploaded from the ADSL Router
SNR Margin (dB) — Displays the current signal-to-noise margin
expressed in decibels (dB). SNR is the ratio of signal power to the noise
power corrupting the signal.
Attentuation (dB) — Displays the amount of attenuation in signal
strength due to conductive losses in transmission medium. Attenuation
affects the propagation of waves and signals in electrical circuits,
expressed in decibels (dB).
Output Power (dBm) — Displays the current input/output power at
the ADSL Router’s DSL interface, expressed in decibels (dB) of the
measured power referenced to one milliwatt (mW).
Attainable Rate (Kbps) — Displays the maximum attainable payload
on the downstream and upstream channels, expressed in kilobits per
second.
Rate — Displays the actual payload carried on the downstream and
upstream channels.
K (number of bytes in DMT frame) — Displays the number of bytes
in a DMT frame. DMT (discrete multi-tone modulation) - is a frequency-
division multiplexing (FDM) scheme utilized as a digital multi-carrier
modulation method.
R (number of check bytes in RS code word) — Displays the
number of redundancy bytes used for error correction. Redundancy bits
are the number of bits used to transmit a message minus the number
of bits of actual information in the message.