HDSL4 for General Distribution Installation and Maintenance Practice
HDSL4 System Testing
61223HDSL4L2-5C
17
H4TU-R Front Panel Pushbuttons
Two front-panel pushbuttons, labeled
LOC
and
REM
, provide hardware control of the
loopbacks.
Pressing the
LOC
pushbutton causes a bidirectional loopback (toward the customer and the
H4TU-C) to occur at the H4TU-R. If a bidirectional loopback is active, pressing the pushbutton
a second time disables the loopback.
Pressing the
REM
pushbutton activates a bidirectional loopback at the H4TU-C (toward the
H4TU-R and network). If the loopback is active, pressing the pushbutton a second time
disables the loopback.
Front Panel LED Indicators
LED indicators mounted on the front panel of the unit provide status of the HDSL4 circuit.
Each indicator is described in
for the H4TU-C and
Table 8. H4TU-C Front Panel LED Indicators
Module
Label
Condition
Description
DSL 1
DSL 2
z
Green
z
Red
DSL Loop 1 and Loop 2 sync, no errors currently
detected, signal margin
≥
3 dB
No DSL Loop 1/ Loop 2 sync, errors being detected, or
signal margin < 3 dB
DSX/DS1
z
Green
z
Red
DSX-1 signal is present, and no errors currently being
detected
In framed mode, denotes loss of framing or loss of sync at
the DSX/DS1 input; in unframed mode, denotes loss of
signal at DSX/DS1 input
ALM
{
Off
z
Red
z
Yellow
No active alarm present
Loss of DSX-1 signal to the unit
Loss of DS1 signal to the remote
ESF/SF
{
Off
z
Yellow
z
Green
Unit is provisioned for unframed data
Unit is provisioned for ESF data
Unit is provisioned for SF data
B8ZS/AMI
z
Yellow
z
Green
Unit is provisioned for B8ZS line code
Unit is provisioned for AMI line code
LBK
{
Off
z
Yellow
Unit is
not
in loopback
Unit is in loopback (network and/or customer)
DSL
1
DSL
2
TX
E
Q
RX
TX
M
O
N
R
S
2
3
2
RX
DSX
DSX
/DS1
ALM
LBK
ESF
/SF
B8ZS
/AMI