ADTRAN Total Access SHDSL LTU, Установка и эксплуатация

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61182118L1-5B Issue 2, July 2004 11
Loopbacks
There are five types of local loopbacks and five types of
remote loopbacks available for each of the two line
interfaces (G.703, and SHDSL). When initiating a
loopback, the first step is choosing a line interface.
When G.703 is chosen, the loopback will occur at the
G.703 drivers and receivers. When SHDSL is chosen,
the loopback will occur at the SHDSL drivers and
receivers. The loopback descriptions and illustrations
are shown in
Table 7 .
NOTE
All remote loopbacks are initiated at the local
2W/4W SHDSL LTU unit.
Table 7. Loopback Types
Loopback Type Description Illustration
Local Dual Sided
Loopback Provides a bidirectional loopback at the LTU.
Remote Dual Sided
Loopback Initiated at the LTU and provides bidirectional
loopback at the NTU.
Local Network
Transparent
Loopback Provides a loopback at the LTU in the network
direction. Data is passed transparently to the
customer side.
Remote Network
Transparent
Loopback Initiated at the LTU and provides a loopback at
the NTU in the network direction. Data is
passed transparently to the customer side.
Local Network
Nontransparent
Loopback Provides a loopback at the LTU in the network
direction. AIS signal is injected into the
customer side.
Remote Network
Nontransparent
Loopback Initiated at the LTU and provides a loopback at
the NTU in the network direction. AIS signal is
injected into the customer side.
Local Customer
Transparent
Loopback Provides a loopback at the LTU in the
customer direction. Data is passed
transparently to the network side.
LTU NTU
LTU NTU
LTU
TX Data
NTU
LTU
TX Data
NTU
LTU
TX AIS
NTU
LTU
TX AIS
NTU
LTU
TX Data
NTU