Hdsl System Testing; Figure 5. Htu-C Bantam Jack Arrangement; Figure 6. Hdsl Loopbacks - ADTRAN 3192 HTU-C Installation And Maintenance Manual

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. 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 DSX EQ Bantam Jacks
The front panel of HTU-C 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
T
DSX-1
R
EQ
RX
EQ
TX
T1
DSX-1
R1

Figure 5. HTU-C Bantam Jack Arrangement

HTU-C Loopbacks
The HTU-C 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, HTU-R, and
HRE loopbacks will be described in subsection 5 of
this practice.
Secondly, the HTU-C responds to the industry defacto
standard for HDSL loopbacks. A detailed description
of these loopback sequences is given in Appendix A.
6
HDSL
HDSL
LOOP 1
LOOP 1
HTU-C
HDSL
DATA
SPAN POWER
PUMP
HDSL HDSL
LOOP 2 LOOP 2
Section 61245004L6-5, Issue 4
The loopback condition imposed in both cases is a
logic level loopback at the point within the HTU-C
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
provides customer-side loopbacks initiated by using
either the terminal control port or in-band loopback
control code sequences (refer to Appendix A of this
practice). In this mode, either an AIS signal or
customer data is supplied to the network.
HTU-C M R Network-Side Loopback
DSX-1
HTU-C M R
HTU-R Network-Side Loopback and/or
HTU-R NIU Loopback
DSX-1
HTU-C M R
HTU-R Customer-Side Loopback
X
AIS
HTU-C M R
HTU-C Customer-Side Loopback
X
AIS
HTU-C M R
HRE Network-Side Loopback
DSX-1
HTU-C M R
HRE Customer-Side Loopback
X
AIS
HTU-C M R
Dual HRE Network-Side Loopback
DSX-1
HTU-C M R HRE
X = Signal Inactive
D = Data Sent

Figure 6. HDSL Loopbacks

AIS
LOCAL
DS1
LOOP
X
HTU-R
AIS
LOCAL
DS1
LOOP
X
HTU-R
LOCAL
DS1
LOOP
HTU-R
LOCAL
DS1
LOOP
HTU-R
AIS
DS1
X
HRE HTU-R
DS1
HTU-R
HRE
AIS
X
X
HRE HTU-R DS1
61245004L6-5D