PRICING AND AVAILABILITY 800.827.0807
TECH SUPPORT 800.726.8663
RETURN FOR REPAIR 256.963.8722
www.adtran.com
61223024L2-22B
Warranty: ADTRAN will replace or repair this product within the warranty period if it does not meet its published specifications or fails while in service.
Warranty information can be found online at www.adtran.com/warranty.
T200 H2TU-R, Locally Powered
TROUBLESHOOTING HDSL2
This ADTRAN HDSL2 unit is equipped with troubleshooting-at-a-glance LEDs (identified on the
reverse side of this document) that provide customers with a simple means of identifying the location
of certain faults. Additionally, screens available via the craft interface simplify the trouble isolation
process. These screens and their associated benefits are described below.
Troubleshooting Screen
Available via the Main Menu - This screen provides ADTRAN contact information and access to the
Troubleshooting Guidance and General Information screens.
Troubleshooting Guidance Screens
Available via the Troubleshooting screen - The firmware detects and displays errors and/or alarms at
any of the monitored inputs (DSX1, DS1 and HDSL). Guidance on the fault(s) detected includes
possible cause(s) and suggested actions, including those shown below:
General Information Screen
Available via the Troubleshooting screen – This is a reference page that displays the minimum
acceptable signal margin, maximum attenuation, and other deployment parameters for this HDSL2
circuit. A sample display of this screen is shown below:
Non-loaded cable pair
Single bridge tap < 2 kft
Total bridge taps < 2.5 kft
Bridge tap within 1000ft of transceiver may affect performance.
Impulse noise < 50 dBrnF (F filter)
Wideband noise < 31 dBrnF (F filter)
Power influence ≤80 dBrnC
Longitudinal Balance ≥60 dB (If using Wideband test at 196 kHz ≥40 dB)
Foreign DC Voltage (t-r, t-g, r-g) < 3 VDC
Loop Resistance ≤775 ohms
Margin ≥6 dB
Attenuation ≤28 dB
Along with the Troubleshooting screens, the Detailed Status screen and Performance History screen,
also available via the craft access port, provide both real-time and historical views of this circuit.
DSX-1/DS1:
LOS Loss of signal (Red Alarm) at the
DSX-1/DS1 receiver
CLK T1 receive clock is out of range
RAI Remote Alarm Indication (Yellow
Alarm) detected at DSX-1/DS1
receiver
AIS Alarm Indication Signal (Blue
Alarm) detected at DSX-1/DS1
receiver
ERR Errors recorded at DSX-1/DS1
receiver
Facility:
GROUND Ground Fault on span (facility pair
grounded)
SHORT Short circuit (or low impedance)
between pairs
OPEN Open circuit between facility pairs
DSL:
LOS Loss of HDSL sync
MARG Margin has exceeded the alarm
threshold
ATTEN Attenuation has exceeded the alarm
threshold
ERR Errors recorded at the HDSL receiver
HIST Performance History of the DSL units
FEATURES
TScan
This module is equipped to function with Central Office units (H2TU-C) having the TScan™feature.
TScan allows for remote retrieval of circuit diagnostics and performs advanced fault location. For more
information about TScan refer to the Installation and Maintenance practice.
Bad Splice Detection
The Runtime TScan splice detection feature is an ADTRAN proprietary non-intrusive method for
detection of anomalies (poor splice connections) in the copper plant.
Data transmission transceivers, especially echo-cancelled technologies, such as HDSL2 (or HDSL4)
are subject to degraded performance in the presence of deteriorating splice connections. This
deterioration is often undetected by normal testing methods. Often, these splices present no problem
for the data transmission equipment until the point at which oxidation within the splice itself causes a
rapid impedance change. Such a change in impedance may cause errors, signal margin fluctuation, and/
or a retrain of the DSL transceivers. To address the difficulty in identifying deteriorating splice
connections, ADTRAN has developed the splice detection feature, which non-intrusively monitors the
cable pair during runtime for the presence of deterioration.
The screen below, accessed from the troubleshooting screen, shows a suspect splice 250 feet from the
H2TU-C.
Fast Retrain
Fast Retrain is an ADTRAN proprietary feature that minimizes downtime due to an intermittent
impairment (bad splice, noise burst, etc.) which due to its duration cannot be bridged.
When such impairments occur after HDSL synchronization has been achieved, the fast retrain feature
will be invoked to restore service within 5 to 7 seconds. This short retrain time allows for reduced
downtime compared to the traditional 25 to 30 second retrain duration.
NOTE: Fast-Retrain capable units must be installed on both ends of the HDSL2 circuit for this
feature to function properly. Also, if there is a failure, for any reason, of a Fast Retrain
attempt then the traditional (25-30 second) retrain will be initiated.
Circuit ID: 06/06/04 09:29:45
Press ESC to return to previous menu
* Note: Chronic Circuit Results are only valid after all other circuit *
* qualification tests have been performed and failed to show a trouble !! *
Splice Detector Version 1 Result Definitions:
---------------------------------------------
NTF - No Trouble Found yet.
LOS - Unit not in sync.
Number - Distance from Reference point (in ft.) of suspect splice.
Reference Splice Detection Version Result Shown
Point Results Number for date
--------- ---------------- ------- MM/DD/YY
H2TUC 250 01 --------
H2TUR NTF -- 06/06/04
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