SMC Networks SMC7904WBRAS-N2 V2 - QUICK, User Manual

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C
HAPTER
7
| WAN Settings
ADSL Settings
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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.
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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.
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AnnexL Option — 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. Once enabled AnnexL increases the range of DSL service,
enabling the link to work at a distance of 7 kilometers, or 23,000 feet.
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AnnexM Option — 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.
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.
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ADSL Capability — ADSL Capability refers to means of manipulating
the bit loading of a connection to increase quality of signal or
transmission rate.
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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.
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SRA — Enables seamless rate adaptation to set the optimal
transmission rate based on existing line conditions.