H2Tu-R Front Panel Pushbuttons; Figure 8. Hdsl2 Loopbacks; Table 8. Front Panel Loopback Pushbuttons - ADTRAN HDSL2 Installation And Maintenance Practice

HDSL2 for General Distribution Installation and Maintenance Practice
In addition to network-side loopbacks, an H2TU-C module provides customer-side loopbacks
initiated by using either the terminal control port or in-band loop codes. For more infor-
mation, refer to "Appendix A, HDSL2
supplied to the network.

H2TU-R Front Panel Pushbuttons

Two loopback ( ) pushbuttons are accessible from the front panel of the H2TU-R. The
LBK
loopback button controls a customer loopback at the H2TU-C. The
controls a bidirectional loopback at the H2TU-R.
operation.
Switch Label Function
Pressing this button changes the H2TU-C loopback state as follows:
REM
• If the H2TU-C is not in loopback, pressing this button will activate a bilateral
• If the H2TU-C is in loopback, pressing this button will deactivate the bilateral
Pressing this button changes the H2TU-R loopback state as follows:
LOC
• If the H2TU-R is not in loopback, pressing this button will activate a bilateral
• If the H2TU-R is in loopback, pressing this button will deactivate the bilateral
61223HDSL2L2-5B
Loopbacks". In this mode, an AIS signal (all ones) is
H2TU-C Network-Side Loopback
DSX-1
H2TU-C
H2TU-R Network-Side Loopback or
DSX-1
H2TU-C
H2TU-R Customer-Side Loopback
X
DSX-1
AIS
H2TU-C
H2TU-C Customer-Side Loopback
X
DSX-1
AIS
H2TU-C
DSX-1
H2TU-C

Figure 8. HDSL2 Loopbacks

Table 8. Front Panel Loopback Pushbuttons

loopback.
loopback.
loopback.
loopback.
AIS
LOCAL
DS1
LOOP
X
H2TU-R
H2TU-R NIU Loopback
AIS
LOCAL
DS1
LOOP
X
H2TU-R
LOCAL
DS1
LOOP
H2TU-R
LOCAL
DS1
LOOP
H2TU-R
H2TU-R Bilateral Loopback
LOCAL
DS1
LOOP
H2TU-R
X = Signal Inactive
Table 8 details the loopback pushbutton
HDSL2 System Testing
loopback button
LOC
REM
15