Triple-Play Service Deployment

Chapter 9: Troubleshooting High Speed Data Service
– If synchronization at the test set cannot be gained, a check for
dial tone will determine if the network is connected to the
central office.
– If there is no dial tone, it is necessary to check for an open using
a loop-troubleshooting tool with a TDR to locate the fault.
– If a dial tone is available, then a check for load coils on the span
is needed. If none are present, the technician must move up the
loop to the next access point, typically the pedestal.
– The technician can disconnect the circuit from the pedestal to
the customer premises equipment and connect the test set to
the loop facing the central office or digital loop carrier.
– If synchronization is successful, the problem is on the loop
between the pedestal and the NID.
– The technician may continue this process, as needed, along the
complete copper span, to check the splice case, cross box, and
main distribution frame.
If synchronization is successful at the NID, the in-home wiring to
the modem or residential gateway (RG) most likely is the cause of
the problem.Typically, this problem is isolated with a simple digital
volt ohmmeter test. An alternative solution is to install a new cable
directly from the NID to the wall outlet at the modem/RG location.
If synchronization is possible in the house but the performance is
poor, the technician must move the test set to the NID to check for
improved performance. If performance shows an improvement,
the cause of the problem likely is faulty in-home wiring. If synchronization
is possible at the NID but performance is poor, the source
of the problem most likely is on the span. The technician should
look at a bits carried per DMT tone graph, and then compare the
bits per DMT tone to the SNR per DMT tone data. Unusual dips in
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