JDS Uniphase SC-ADSL-A, Руководство пользователя

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Chapter 9 Troubleshooting
Resolving problems
SmartClass ADSL/Copper Tester User’s Guide 67
General testing
The following section addresses questions about testing in general using
SmartClass Testers.
Issue
Inconsistent test results.
Resolution
Verify that your test leads are good and are connected properly for the test you
are performing.
Turn the unit off then back on, and then try again.
ADSL testing
The following section addresses questions about ADSL testing.
Issue
The modem cannot achieve synchronization with the Central Office (CO).
Resolution
Inability to sync can have many causes. Perform the following steps to trouble-
shoot:
Disconnect the customer's ADSL modem.
Verify you are connected to the correct pair.
Make sure that you are connected on pins 3 and 4 instead of 2 and 5.
Isolate the premise wiring.
Check for a premise alarm system.
Verify that the copper pair is provisioned for ADSL at the CO.
Try testing at the CO/Exchange on the customer pair.
Check the DSLAM modem vendor and software version to verify compatibility
with the ADSL/Copper Tester.
Issue
The modem gets sync with the CO, but the rate is lower than expected.
Resolution
Verify that you are on an ADSL2 or ADSL2+ line.
Check the Bits per Tone (BPT) and the Signal to Noise Ratio (SNR) per tone
graphs for areas of the spectrum with low throughput. This could be caused by
bridged taps, cable crosstalk, or AM radio.
Check whether the max rate on the DSLAM is limited.
Check for a premise alarm system on the same pair.
Check the attenuation.