Dsl And Plm; Figure 3-2: Typical Dsl Setup - Focal 922-DSLH User Manual

3.1 DSL and PLM

The Digital Subscriber Line (DSL) used in the 922-DSLH design is the Symmetrical High-speed Digital
Subscriber Line (SHDSL). This SHDSL signaling uses a base band transmission scheme with equal transmit
and receive data rates over a single pair of wires. SHDSL supports twisted or untwisted wire pairs. For the
remainder of the document, SHDSL will simply be referred to as DSL.
To pass the DSL communications on the same wire as 50/60 Hz AC power, the Power Line Module (PLM) must
be used as well as a power line filter. This PLM couples, with capacitors, the DSL signal onto the power line
cable and blocks the AC power 50/60 Hz signal from affecting the DSL circuit. In addition to the PLM the AC
noise and harmonics need to be isolated from the DSL link. In most cases all that is needed to give this isolation
are inductors (3.3 mH) as shown in the figure below. Inductors are needed at both the AC source and the AC
load as shown. Since most systems will specify different amperage levels and the power line noise levels may
be different, the power line inductor requirements could be custom for each setup.
The figure below shows a typical DSL setup using the 922-DSLH cards. Note that one card is configured as
console (STU-C) and the other card is configure as remote (STU-R). The card configuration is done via an
Ethernet connection to the card using the sample GUI. Note that the as-shipped factory default configuration is
STU-C.
DSL MODEM (CONSOLE)
3300uH
AC POWER
SOURCE
3300uH
The DSL daughter card acts as a media converter and converts Ethernet to DSL and DSL to Ethernet. The
Ethernet communication link can operate at 10 or 100 Mbps and the DSL communication link can operate
between 64 Kbps to 15296 Kbps. The DSL daughter card has limited data storage; therefore, the data throughput
on the Ethernet link should be controlled (flow control) to ensure that it does not exceed the throughput of the
DSL link speed; otherwise data will be lost. The Ethernet and DSL speeds are controlled through the diagnostics
GUI (P/N: 922-0414-00).
On power up of the 922-DSLH board the DSL daughter card will attempt to link to a connected DSL interface.
Link negotiation may take 1 to 2 minutes before completion, at which point data traffic can start.
Focal Technologies Corporation
A Moog Inc. Company
DSL
PLM

Figure 3-2: Typical DSL Setup

Model 922-DSLH – User Manual
DSL MODEM (REMOTE)
DSL
PLM
Document No. 922-0677-00, Rev 1.0
3300uH LINE
TO
LOAD
NEUTRAL
3300uH
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