SMC Networks BARRICADE SMC7901WBRA2 B1, User Manual

Page: 54 / 150

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.
D
OWNSTREAM
/U
PSTREAM
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.