Unit installation

61223026L2-5A Issue 1, November 2003 5
When the circuit pack is installed in any of the H2TU-R
enclosures, all connections are made through the
enclosure backplanes.
NOTE
Ensure that the chassis ground is properly
connected for either standalone or shelf
mounted applications.
4. HDSL2 SYSTEM TESTING
The T200 H2TU-R provides diagnostic, loopback, and
signal monitoring capabilities.
The six front-panel LEDs provide diagnostics for
HDSL2 loops, DS1 signals, alarms, provisioning, and
loopbacks. See Table 4 on page 4 of this practice for
details.
The H2TU-R provides local and remote loopback
capabilities via the loopback pushbutton on the front
panel.
The DS1
MON jacks provide access for DS1 signal
monitoring.
DS1 MON Bantam Jacks
The
MON jack provides a non-intrusive access point for
monitoring the characteristics of the transmit and
receive signals at the DS1 interface point. For example,
the DS1
MON jack on the H2TU-R could be used to
connect to a bit error rate tester to monitor for synchro-
nization, test patterns, etc. Figure 2 is an illustration of
specific jack detail.
l
Figure 2. H2TU-R MON Diagram
H2TU-R Network Loopbacks
The H2TU-R responds to multiple loopback activation
processes in the following order.
• First, loopback activation may be accomplished
using the control port of the H2TU-C or H2TU-R.
• Second, the H2TU-R will respond to the industry
standard HDSL loopback codes as designated in the
ANSI document T1E1.4/92. A synopsis of the
method described by ANSI is presented in Appen-
dix A of this practice.
• Third, the H2TU-R responds to T1 Network
Interface Unit smartjack loopback codes as
described in Bellcore TR-TSY-000312 if the
H2TU-R is optioned for smartjack loopback
enabled. The smartjack loopback codes are also
provided in Appendix A, HDSL2 Loopbacks.
This unit contains smartloop technology. That is, it
constantly monitors the DSX-1 for a framing pattern.
The unit will initiate the proper loopback regardless of
how the loopback control sequence is sent (framed or
unframed).
Receiving the in-band codes for more than five seconds
or the ESF codes four consecutive times will cause the
appropriate loopback action.
The H2TU-R will respond to the loopback codes by
activating the smartjack loopback from either the
disarmed or armed state. The loop down codes will
return the unit to its previous state (armed or normal).
Refer to Appendix A, HDSL2 Loopbacks for more
details on loopbacks and loopback arming sequences.
Customer Loopbacks
In addition to the loopbacks in the direction of the
network, the H2TU-R may also be looped back in the
direction of the customer using any one of the following
methods:
• the terminal control port of the H2TU-C,
• the terminal control port of the H2TU-R, or
• the front-panel
LOC LBK button of the H2TU-R.
The H2TU-C can be looped using the
REM LBK button
on the front panel of the H2TU-R.
The H2TU-C and H2TU-R Customer Side Loopbacks
are illustrated in Figure 3.
Tx
Rx
DS1
MON
CPE
DS1
INTERFACE
H2TUR
T
R
T1
R1