Bad Splice Detection (Tscan); Managing Tscan; Bad Splice Detection (Tscan) Menu - ADTRAN 6540 Installation And Maintenance Manual

Bad Splice Detection (TScan)

The SHDSL 2-Wire/4-Wire NTUs provide bad splice protection using the ADTRAN propri-
etary Runtime TScan
algorithm that enables SHDSL 2-Wire/4-Wire NTUs to detect anomalies (bad splices) in the
copper pair. This feature can aid in troubleshooting the distribution plant.
Data transmission transceivers (especially echo-cancelled technologies) are subject to perfor-
mance degradations and errors in the presence of bad splice connections. A splice may be
benign for a period of time, allowing a circuit to behave appropriately for portions of the day.
Over time the splice can oxidize and incur small, rapid changes in impedance. This inconsis-
tency in behavior makes the problem difficult to locate. Additionally, an impedance change
that is large enough to cause the transceiver trouble may still be small enough to be
undetected by test equipment used on the copper pairs.
The splice detection algorithm is designed to detect bad splices in data mode. The detector
runs periodically after a SHDSL 2-Wire/4-Wire NTU achieves synchronization. The SHDSL
transceiver monitors the loop for impedance changes that are of a magnitude to degrade the
received signal of the transceiver. When the transceiver detects a significant impedance
change, the approximate distance from that transceiver to the anomaly is recorded on a menu
screen, the Bad Splice Detection (TSCAN) 24 Hour Counts menu screen, by incrementing the
appropriate counter. When enough counts are accumulated at a particular distance, this
distance is reported on the Bad Splice Detection (TSCAN) menu screen.
NOTE
The Splice Detection Feature is included with this product as an aid to
troubleshooting. Due to inconsistency in environmental conditions and their
effect on telecommunications plant, ADTRAN cannot guarantee the accuracy
of the measurements. Comparison to existing engineering drawings should
provide exact locations of suspect splices indicated by ADTRAN algorithms.

Managing TScan

The VT100 local management port allows access to the splice detection menus through the
TSCAN selection from the Main Menu (refer to
Wire NTU Main Menus provide access to the module. The Main Menu options have several
functions and submenus that identify and provide access to specific operations and param-
eters.

Bad Splice Detection (TSCAN) Menu

The Bad Splice Detection (TSCAN) menu displays a summary of the bad splice results (see
Figure
• If a SHDSL loop is in good condition, a "No Trouble Found" status appears in the results
• If a count register exceeds a certain threshold, a bad splice is predicted to exist at this
• If more than one count register exceeds the threshold, then the count that is larger displays
61230001E1-5E

2.0 splice protection feature. TScan splice detection is a non-intrusive
17).
column.
distance and displays in the results column.
as a bad splice.
Figure 14 on page 26). The SHDSL 2-Wire/4-
Troubleshooting
33