Product specifications

61223006L1-5C Issue 3, December 2003 7
4. HDSL2 SYSTEM TESTING
The ADTRAN HDSL2 system provides the ability to
monitor the status and performance of the DSX-1
signals, DS1 signals, and HDSL2 loop signals. Detailed
performance monitoring is provided by the front panel-
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 HDSL2 system. The following subsec-
tions describe additional testing features.
H2TU-C Bantam Jacks
The front panel of the H2TU-C contains both
monitoring and metallic splitting Bantam jacks. In
general, the monitoring jacks provide a non-intrusive
tap onto a signal line that permits the connection of test
equipment to monitor the characteristics of that signal.
For example, the DSX-1 monitor jack can be used to
connect to a bit error rate tester to monitor for synchro-
nization, test patterns, etc. The metallic splitting jacks
provide an intrusive, signal interrupting access to the
line. It is very important to know the direction of the
access provided by a metallic splitting jack.
Figure 5 illustrates the complete Bantam jack
arrangement and details for specific jacks.
Figure 5. H2TU-C Bantam Jack Arrangement
H2TU-C Loopbacks
The H2TUC responds to two different loopback
activation processes.
• First, loopbacks may be activated using the craft
interface. The Loopback Options Screen that
provides for the H2TU-C and H2TU-R loopbacks is
described in the Control Port Operation section of
this Practice.
• Second, the H2TU-C responds to the industry
standard patterns for HDSL loopbacks. A detailed
description of these loopback sequences is given in
Appendix A.
This unit contains smartloop technology. That is, the
unit will initiate the proper loopback regardless of how
the loopback control sequence is sent (framed or
unframed).
The loopback condition imposed in each case is a logic
level loopback at the point within the H2TU-C where
the DSX1 signal passes into the HDSL2 modulators.
Figure 6 depicts all of the loopback locations possible
with ADTRAN HDSL2 equipment.
Figure 6. HDSL2 Loopbacks
In addition to network side loopbacks, the H2TU-C
provides customer side loopbacks initiated by using
either the terminal control port or in-band loop codes
(see Appendix A). In this mode, an AIS signal is trans-
mitted to the network.
DSX-1
MON
RX
H2TU-C
Data
Pump
D
SX-1
T1
R1
D
SX-1
T
R
HDSL2
EQ
RX
DSX-1
MON
TX
EQ
TX
Power
DSX-1
H2TU-C
LOCAL
LOOP
H2TU-C Network-Side Loopback
H2TU-R
H2TU-C
LOCAL
LOOP
H2TU-R Customer-Side Loopback
H2TU-R
H2TU-C
LOCAL
LOOP
H2TU-C Customer-Side Loopback
H2TU-R
X
X
DS1
DSX-1
H2TU-C
LOCAL
LOOP
H2TU-R Network-Side Loopback or
H2TU-R NIU Loopback Smartjack
H2TU-R
X
DS1
DS
1
DS
1
X
AIS
AIS
AIS
AIS
X = Signal Inactive
D = Data Sent
H2TU-C
LOCAL
LOOP
H2TU-R Bidirectional Loopback
DS1
D
SX-1
H2TU-R