SMC Networks BARRICADE SMC7901WBRA2 B1, User Manual

Page: 66 / 150

C
HAPTER
5
| WAN Configuration
ADSL Settings
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G.dmt — A standard that defines full-rate ADSL, and utilizes Discrete
Multi-Tone (DMT) signaling to transmit data at up to 8 Mbps
downstream and 640 Kbps upstream.
◆
T1.413 — ANSI standard that defines the requirements for ADSL for
the interface between the telecommunications network and the
customer installation in terms of their interaction and electrical
characteristics. (The Gateway complies with Issue 2 of this standard.)
◆
ADSL2 — This standard extends the capability of basic ADSL data rates
to 12 Mbit/s downstream and 3 Mbit/s upstream (with a mandatory
capability of ADSL2 transceivers of 8 Mbit/s downstream and 800 Kbit/s
upstream.
◆
ADSL2+ — This standard extends the capability of basic ADSL data
rates to 24 Mbit/s downstream and 1.4 Mbit/s upstream depending on
the distance from the DSLAM to the customer's home.
A
NNEX
L O
PTION
Annex L is an optional specification in the ITU-T ADSL2 recomendation
G.992.3 titled “Specific requirements for a Reach Extended ADSL2
(READSL2) system operating in the frequency band above POTS.” It is
often referred to as Reach Extended ADSL2 or READSL2.
◆
Enabled — Once enabled AnnexL increases the range of DSL service,
enabling the link to work at a distance of 7 kilometers, or 23,000 feet.
A
NNEX
M O
PTION
Annex M is an optional specification in ITU-T recomendations G.992.3
(ADSL2) and G.992.5 (ADSL2+), also referred to as ADSL2 M and ADSL2+
M. This specification extends the capability of commonly deployed Annex A
by more than doubling the number of upstream bits.
◆
Enabled — Once enabled AnnexM increases upload speeds by the
shifting the upstream/downstream frequency split from 138 kHz up to
276 kHz, allowing the maximum upstream bandwidth to be increased
from 1.4 Mbit/s to 3.3 Mbit/s.
ADSL C
APABILITY
ADSL Capability refers to means of manipulating the bit loading of a
connection to increase quality of signal or transmission rate.
◆
Bitswap — Enables bit swapping. Bit swapping is a way of swapping
the bit-loading of a noisy tone with another tone in the symbol which is
not as noisy. The bit loading from a specific tone can be increased or
decreased. In addition, the TX power can be increased or decreased for
a specific tone. However, there is no change in the overall payload rate
after the bit swap operation.
◆
SRA — Enables seamless rate adaptation to set the optimal
transmission rate based on existing line conditions.