ADTRAN 1245001L6, Руководство по установке и обслуживанию

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6 Section 61245001L6-5, Issue 7 61245001L6-5G
4. HDSL SYSTEM TESTING
The ADTRAN HDSL system provides the ability to
monitor the status and performance of the DSX-1
signals, DS1 signals, and HDSL loop signals.
Detailed performance monitoring is provided by the
faceplate mounted RS-232 Control Port or the
ADTRAN HDSL Fuse/Alarm/Control Unit (HFAC)
Shelf Controller. These features are valuable in
troubleshooting and isolating any system level
problems that may occur at installation or during
operation of the HDSL system. The following
subsections describe additional testing features.
HTU-C M R EQ Bantam Jacks
The front panel of HTU-C M R contains metallic
splitting bantam jacks for access to DSX-1 Tx and
Rx from the local loop. This permits intrusive
testing of the DSX-1 traffic on the HDSL local loop.
Figure 5
shows access provided by the DSX EQ
bantam jacks.
HTU-C M R Loopbacks
The HTU-C M R responds to two different loopback
activation processes. First, loopback may be
activated using the craft interface. The Loopback
Options Screen which provides for the HTU-C M R,
HTU-R, and HRE loopbacks are described in
subsection 5 of this practice
Secondly, the HTU-C M R responds to the industry
defacto standard for HDSL loopbacks. A detailed
description of these loopback sequences is given in
Appendix A.
This unit contains smartloop technology. That is, if
the unit is optioned to operate in an unframed mode,
it constantly monitors the DSX-1 for a framing
pattern. If a framed loopback control sequence is
sent, then the unit will initiate the proper loopback
command (see Appendix A of this practice).
The loopback condition imposed in both cases is a
logic level loopback at the point within the
HTU-C M R where the DSX-1 signal passes into the
HDSL modulators.
Figure 6
depicts all of the
loopback locations possible with ADTRAN HDSL
equipment.
In addition to network-side loopbacks, the
HTU-C M R provides customer-side loopbacks
initiated by using either the terminal control port or
inband loop codes (see Appendix A). In this mode,
an AIS signal is supplied to the network.
HTU-C
DATA
PUMP
HDSL
SPAN POWER
DSX-1
T
R
DSX-1
T1
R1
HDSL
LOOP 1
HDSL
LOOP 2
HTU-C M R
HDSL
LOOP 1
HDSL
LOOP 2
EQ
RX
EQ
TX
Figure 5. HTU-C Bantam Jack Arrangement
Figure 6. HDSL Loopbacks
DSX-1
HTU-C
LOCAL
LOOP
HTU-C Network-Side Loopback
HTU-R
HTU-C
LOCAL
LOOP
HTU-R Customer-Side Loopback
HTU-R
HTU-C
LOCAL
LOOP
HTU-C Customer-Side Loopback
HTU-R
X
X
DS1
DSX-1
HTU-C
LOCAL
LOOP
HTU-R Network-Side Loopback and/or
HTU-R NIU Loopback
HTU-R
X
DS1
DS1
DS1
X
AIS
AIS
X
HRE Customer-Side Loopback
DS1 AIS
HTU-C
HRE Network-Side Loopback
HTU-R
DS1 DSX-1
HRE
AIS
AIS
AIS
X
HTU-C HTU-R HRE
X = Signal Inactive
D = Data Sent
HTU-C
Dual HRE Network-Side Loopback
HRE
DSX-1
HRE HTU-R
X
X
DS1
AIS
HTU-C
LOCAL
LOOP
Bilateral Loopback
DS1 DSX-1
HTU-R