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V
ERIFICATION
After the H4TU-R is installed, verify that it is operating properly by monitoring the status
LEDs on the front panel.
LED Status
ALM LED (red)
Blinking LOS condition at the T1 input of the line unit.
LP1 and LP2 LEDs (green)
Blinking Once per second = HDSL4 loop is trying to acquire sync.
(a)
ESF and SF LEDs
(green)
ESF
SF
ESF and SF
Blinking
ESF and SF
(a) (b)
B8ZS and AMI LEDs
(green)
B8ZS LED
Blinking Once per second = String of excessive zeros detected.
AMI LED
Blinking Once per second = Bipolar Violation (BPV) detected.
LBK LED (yellow)
Blinking Once per second = Customer Local (CLOC) loopback state.
(a) If DS1 signals are not detected, the ESF, SF, B8ZS, and AMI LEDs do not illuminate.
(b) When optioned for AUTO LINE CODE, these LEDs indicate when an AMI or B8ZS DS1 code is detected.
R
EACH
The maximum reach of the H4TU-R-402 is based on a maximum signal loss over span 1 of
47 dB@196 kHz and a a maximum signal loss over spans 2 and 3 of 43 dB@196 kHz. The
following table lists the reach as a function of cable gauge.
Cable Gauge
26 (0.4 mm)
24 (0.51 mm)
22 (0.61 mm)
19 (0.91 mm)
(a) Insertion Loss = 1.38 times loop attenuation
L
OGGING ON TO THE
The H4TU-R-402 supports local and remote logon through a maintenance terminal (VT100
or a PC running VT100 terminal-emulation software). In HDSL4 systems equipped with the
H4TU-C, the maintenance terminal connects to the H4TU-C front panel craft port. In
HDSL4 systems equipped with the H4LXC, the maintenance terminal connects to the front
panel craft port of the Shelf Control Unit (SCU) controlling the H4LXC.
Remote login creates menus and screens for the H4TU-R that are identical to those viewed
at the H4TU-C or H4LXC. Once logged on, you can view system settings and inventory,
initiate loopbacks, monitor performance, and provision the circuit.
Status LED Descriptions
Description
Indicates alarm state for remote and local Loss of Signal (LOS).
Solid Loss of Signal (LOS) condition at the T1 input of the HRU.
Indicates HDSL4 Loop 1 (LP1) and Loop 2 (LP2) condition.
Solid Solid green = HDSL4 loop is in sync.
4 times per second = Margin alarm condition on HDSL4 loop.
10 times per second = Cyclical Redundancy Check (CRC) error on HDSL4 loop.
OFF No activity on HDSL4 loop.
Indicates framing patterns.
Solid
Extended Super Frame (ESF) framing pattern.
Solid
Super Frame (SF) framing pattern.
Once per second = Frame error detected.
OFF
Unframed or no signal.
Indicates DS1 code options.
Solid
DS1 line code option is set to Bipolar with 8-Zero Substitution (B8ZS).
Solid
User DS1 line code option is set to Alternate Mark Inversion (AMI).
Shows loopback states to and from the network and to and from the Customer
Interface (CI).
Solid Network Remote (NREM), SmartJack (SMJK), or Transmit Loss of Signal
(TLOS) loopback.
4 times per second = HRU in Armed state.
HDSL4 Maximum Reach Chart
Reach (kft.)
Span 1
Spans 2 and 3
12
11.0
16
15.0
21
20.6
29
27.8
Loop Attenuation
(dB per kft.)
@196 kHz (dB per kft.)
2.8
2.0
1.6
1.1
M
M
AIN
(a)
Insertion Loss
3.88
2.84
2.18
1.54
ENU
Ω /
kft.
83
52
32
16
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