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Description of the technology
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3.4 Topologies
SHDSL connections are exclusively point-to-point connections (a characteristic they share
with Ethernet connections). Multi-point connections as with an RS-485 bus system are not
possible. Branch lines are not permitted, because they cause reflections. The reflections
cause high interference or make it impossible to establish a connection.
3.4.1 Point-to-point connection
Figure 3-10 Point-to-point connection
A point-to-point connection is a direct connection between two devices without an interme-
diate station. The line is reserved for both devices during communication.
Data rates for a point-to-point connection
– in 2-wire operation up to 15.3 Mbps
– in 4-wire operation up to 30 Mbps
The 2-wire operation is sufficient for a simple point-to-point application.
The 4-wire operation is recommended for applications with high bandwidth requirements
and applications that require high reliability. You can also route the SHDSL lines A and B
separately from each other. The lines can be of different lengths and be operated at different
data rates.
SH
D
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E TH
SH
D
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SH D S L 4 Wire
m a x. 3 0 M B it/s
SH
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SH
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SH D S L 2 Wire
m a x. 1 5, 3 M B it/s